Lunar bulk chemical composition: a post-Gravity Recovery and Interior Laboratory reassessment.

PubMed

Taylor, G Jeffrey; Wieczorek, Mark A

2014-09-13

New estimates of the thickness of the lunar highlands crust based on data from the Gravity Recovery and Interior Laboratory mission, allow us to reassess the abundances of refractory elements in the Moon. Previous estimates of the Moon fall into two distinct groups: earthlike and a 50% enrichment in the Moon compared with the Earth. Revised crustal thicknesses and compositional information from remote sensing and lunar samples indicate that the crust contributes 1.13-1.85 wt% Al2O3 to the bulk Moon abundance. Mare basalt Al2O3 concentrations (8-10 wt%) and Al2O3 partitioning behaviour between melt and pyroxene during partial melting indicate mantle Al2O3 concentration in the range 1.3-3.1 wt%, depending on the relative amounts of pyroxene and olivine. Using crustal and mantle mass fractions, we show that that the Moon and the Earth most likely have the same (within 20%) concentrations of refractory elements. This allows us to use correlations between pairs of refractory and volatile elements to confirm that lunar abundances of moderately volatile elements such as K, Rb and Cs are depleted by 75% in the Moon compared with the Earth and that highly volatile elements, such as Tl and Cd, are depleted by 99%. The earthlike refractory abundances and depleted volatile abundances are strong constraints on lunar formation processes. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

The isotope composition of selenium in chondrites constrains the depletion mechanism of volatile elements in solar system materials

NASA Astrophysics Data System (ADS)

Vollstaedt, Hauke; Mezger, Klaus; Leya, Ingo

2016-09-01

Solar nebula processes led to a depletion of volatile elements in different chondrite groups when compared to the bulk chemical composition of the solar system deduced from the Sun's photosphere. For moderately-volatile elements, this depletion primarily correlates with the element condensation temperature and is possibly caused by incomplete condensation from a hot solar nebula, evaporative loss from the precursor dust, and/or inherited from the interstellar medium. Element concentrations and interelement ratios of volatile elements do not provide a clear picture about responsible mechanisms. Here, the abundance and stable isotope composition of the moderately- to highly-volatile element Se are investigated in carbonaceous, ordinary, and enstatite chondrites to constrain the mechanism responsible for the depletion of volatile elements in planetary bodies of the inner solar system and to define a δ 82 / 78 Se value for the bulk solar system. The δ 82 / 78 Se of the studied chondrite falls are identical within their measurement uncertainties with a mean of - 0.20 ± 0.26 ‰ (2 s.d., n = 14, relative to NIST SRM 3149) despite Se abundance depletions of up to a factor of 2.5 with respect to the CI group. The absence of resolvable Se isotope fractionation rules out a kinetic Rayleigh-type incomplete condensation of Se from the hot solar nebula or partial kinetic evaporative loss on the precursor material and/or the parent bodies. The Se depletion, if acquired during partial condensation or evaporative loss, therefore must have occurred under near equilibrium conditions to prevent measurable isotope fractionation. Alternatively, the depletion and cooling of the nebula could have occurred simultaneously due to the continuous removal of gas and fine particles by the solar wind accompanied by the quantitative condensation of elements from the pre-depleted gas. In this scenario the condensation of elements does not require equilibrium conditions to avoid isotope fractionation. The results further suggest that the processes causing the high variability of Se concentrations and depletions in ordinary and enstatite chondrites did not involve any measurable isotope fractionation. Different degrees of element depletions and isotope fractionations of the moderately-volatile elements Zn, S, and Se in ordinary and enstatite chondrites indicate that their volatility is controlled by the thermal stabilities of their host phases and not by the condensation temperature under canonical nebular conditions.

An experimental investigation of agglutinate melting mechanisms - Shocked mixtures of sodium and potassium feldspars

NASA Technical Reports Server (NTRS)

Simon, S. B.; Papike, J. J.; Horz, F.; See, T. H.

1985-01-01

The results of an experiment designed to test the validity of the model for agglutinate formation involving fusion of the finest fraction or F3 are reported. Impact glasses were formed from various mixes of orthoclase and albite powders, which were used as analogs for soils with chemically constrasting coarse and fine fractions. The results showed that the single most important factor displacing the composition of a small-scale impact melt from the bulk composition of the source regolith is the fractionated composition of the finest soil fraction. Volatile loss and the amount of melting, which in turn are determined by the degree of shock, are also important. As predicted by the model, the lower pressure melts are the most fractionated, and higher pressure is accompanied by increased melting causing glass compositions to approach the bulk. In general, the systematics predicted by the model are observed; the model appears to be valid.

Ag Isotopic Evolution of the Mantle During Accretion: New Constraints from Pd and Ag Metal-Silicate Partitioning

NASA Technical Reports Server (NTRS)

Righter, K.; Schonbachler, M.

2018-01-01

Decay of (sup 107) Pd to (sup 107) Ag has a half-life of 6.5 times 10 (sup 6) mega-annums. Because these elements are siderophile but also volatile, they offer potential constraints on the timing of core formation as well as volatile addition. Initial modelling has shown that the Ag isotopic composition of the bulk silicate Earth (BSE) can be explained if accretion occurs with late volatile addition. These arguments were tested for sensitivity for pre-cursor Pd/Ag contents, and for a fixed Pd/Ag ratio of the BSE of 0.1. New Ag and Pd partitioning data has allowed a better understanding of the partitioning behavior of Pd and Ag during core formation. The effects of S, C and Si, and the effect of high temperature and pressure has been evaluated. We can now calculate D(Ag) and D(Pd) over the wide range of PT conditions and variable metallic liquid compositions that are known during accretion. We then use this new partitioning information to revisit the Ag isotopic composition of the BSE during accretion.

To melt is not enough: Retention of volatile species through internal processing in icy bodies

NASA Astrophysics Data System (ADS)

Sarid, G.; Stewart-Mukhopadhyay, S.

2014-07-01

The outer Solar System hosts a vast population of small icy bodies, considered to be primitive remnants from the planet-formation epoch. Early thermal and collisional processes affected such planetesimals to varying degrees depending on the time scale and dynamics of early planet growth. Recent observations have revealed that many large (>˜1000 km in diameter) transneptunian objects (TNOs) exhibit features of crystalline water ice in their surface spectra [1], as well as spectral features of more volatile ices, such as methane or hydrated ammonia [2]. These telltale observations should be accounted for when considering the alteration history and bulk processing of dwarf planets and their icy progeny. We will discuss preliminary calculations of early evolution scenarios for small icy-rocky bodies formed beyond the water-ice snow line. Such objects should also contain non-negligible fractions of pre-organic volatile compounds. The volatile composition and interior structure of these objects may change considerably due to internal heating and/or collisional modification prior to settling in their current (relatively quiescent) dynamical niches. Our initial model for the objects in question is that of a porous aggregate of various volatile compounds (as ices or trapped gases) and refractory silicate-metal solid grains, comprising the bulk matrix [3]. Chemical compositions for these objects are taken from existing simulations of chemical and dynamical evolution of disk material [4]. The key volatile species (e.g., H_2O, CO, CO_2, NH_3, CH_4, and CH_3OH) are also the most commonly observed in comets [5], which are remnants of such an early planetesimal population. Thermal and chemical internal evolution is examined self-consistently, as the abundances and locations of all species evolve, and we record mass ratios, temperatures, pressures, and porosity variations. The presence of volatile species in the interior can affect the overall heat balance and accompanied phase transitions [6,7]. Another important factor involving volatiles, mostly water ice, is the effect of shock- induced melting and vaporization on the fragmentation and flow regimes within the body, during massive collision events [8]. To explore the effects of collisions on the internal distributions of volatiles, we conduct 3D numerical simulations of collisions between porous icy bodies using the CTH shock-physics code [9]. The spatially heterogeneous effects of shock-induced heating, pore compaction, and bulk brecciation and redistribution of materials are used to estimate the post-impact re-equilibration of internal volatiles following collisions between similarly-sized bodies. We follow a long-term thermal evolution calculation (> 700 Myr), through the bulk alteration of temperature, porosity and composition for icy dwarf planets (>1000 km in diameter). Some initial configurations result in a complex, differentiated structure, where the deep interior holds a few percent of water melt fraction, while there are shallower layers that can retain conditions for volatile-ice preservation (CO_2 and HCN, for this specific model). There exists a distinct separation between the warmer interior, which is much more compacted and hydrous, and the colder exterior, which is much more porous and stratified. If an evolved object, such as this, is subject to a massive collision, the effects of partial melting and porosity quenching may actually serve to trap more volatile species. We show that for massive collisions of icy bodies, the effect of melting may be grossly over-estimated, if extrapolated from that of cratering events. Interestingly, oblique impacts (> 45 deg) will result in less than half of the volume experiencing pressures corresponding to water-ice melting. This means that the deep interior will not necessarily experience extreme alteration. Such an effect could even be more pronounced for porous or partially-differentiated objects. We focus on understanding the effects of different collision regimes (e.g., merging, disruption, hit-and-run, and graze-and-merge) on early volatile preservation. These regimes include potential moon-forming collisions between large TNOs. In the future, such results can be used to estimate the cumulative effects of multiple impacts. For that purpose, we need to understand the survival of water and more volatile species, as a function of their initial phases, objects' size and density (porosity), and the relative timing of collisional and thermo-chemical evolution.

Proceedings of the MECA Workshop on The Evoluation of the Martian Atmosphere

NASA Technical Reports Server (NTRS)

Carr, M. (Editor); James, P. (Editor); Conway, L. (Editor); Pepin, R. (Editor); Pollack, J. (Editor)

1985-01-01

Topics addressed include: Mars' volatile budget; climatic implications of martian channels; bulk composition of Mars; accreted water inventory; evolution of CO2; dust storms; nonlinear frost albedo feedback on Mars; martian atmospheric evolution; effects of asteroidal and cometary impacts; and water exchange between the regolith and the atmosphere/cap system over obliquity timescales.

The Chlorine Isotopic Composition Of Lunar UrKREEP

NASA Technical Reports Server (NTRS)

Barnes, J. J.; Tartese, R.; Anand, M.; McCubbin, F. M.; Neal, C. R.; Franchi, I. A.

2016-01-01

Since the long standing paradigm of an anhydrous Moon was challenged there has been a renewed focus on investigating volatiles in a variety of lunar samples. Numerous studies have examined the abundances and isotopic compositions of volatiles in lunar apatite, Ca5(PO4)3(F,Cl,OH). In particular, apatite has been used as a tool for assessing the sources of H2O in the lunar interior. However, current models for the Moon's formation have yet to fully account for its thermal evolution in the presence of H2O and other volatiles. For ex-ample, in the context of the lunar magma ocean (LMO) model, it is anticipated that chlorine (and other volatiles) should have been concentrated in the late-stage LMO residual melts (i.e., the dregs enriched in incompatible elements such as K, REEs (Rare Earth Elements), and P, collectively called KREEP, and in its primitive form - urKREEP, given its incompatibility in mafic minerals like olivine and pyroxene, which were the dominant phases that crystallized early in the cumulate pile of the LMO. When compared to chondritic meteorites and terrestrial rocks, lunar samples have exotic chlorine isotope compositions, which are difficult to explain in light of the abundance and isotopic composition of other volatile species, especially H, and the current estimates for chlorine and H2O in the bulk silicate Moon (BSM). In order to better understand the processes involved in giving rise to the heavy chlorine isotope compositions of lunar samples, we have performed a comprehensive in situ high precision study of chlorine isotopes in lunar apatite from a suite of Apollo samples covering a range of geochemical characteristics and petrologic types.

Elemental Compositions of Extrasolar Planetesimals

NASA Astrophysics Data System (ADS)

Xu, Siyi; Jura, M.

2014-01-01

The composition of extrasolar rocky planets is essential for understanding the formation and evolution of these alien worlds. Studying externally-polluted white dwarfs provides the only method to directly measure the elemental compositions of extrasolar planetesimals, the building blocks of planets. The standard model is that some planetesimals can survive to the white dwarf phase, get perturbed, enter into the tidal radius of the white dwarf and get accreted, polluting its pure hydrogen or helium atmosphere. We have been performing high-resolution spectroscopic observations on a number of polluted white dwarfs to measure the bulk compositions of the accreted objects. To have a full picture of the abundance pattern, we gathered data from both Keck/HIRES and HST/COS. I will present the analysis for one of the most interesting objects -- G29-38. It is the first white dwarf identified with an infrared excess from debris of pulverized planetesimals and among the very first identified polluted hydrogen atmosphere white dwarfs. Our analysis indicates that the accreted extrasolar planetesimal is enhanced in refractory elements and depleted in volatile elements. A detailed comparison with solar system objects show that the observed composition can be best interpreted as a blend of chondritic object with some refractory-rich material, a result from post-nebular processing. When all polluted white dwarfs are viewed as an ensemble, we find that the elemental compositions of accreted extrasolar planetesimals resemble to those of solar system objects to zeroth order. (i) The big four elements, O, Fe, Mg and Si are also dominant. Objects with exotic compositions, e.g. diamond planets and refractory-dominated planets, are yet to be found. (ii) Volatiles, such as carbon and water, are only trace constituents. In terms of bulk composition, solar system objects are essentially normal.

Theoretical predictions of volatile bearing phases and volatile resources in some carbonaceous chondrites

NASA Technical Reports Server (NTRS)

Ganguly, Jibamitra; Saxena, Surendra K.

1989-01-01

Carbonaceous chondrites are usually believed to be the primary constituents of near-Earth asteroids and Phobos and Diemos, and are potential resources of fuels which may be exploited for future planetary missions. The nature and abundances are calculated of the major volatile bearing and other phases, including the vapor phase that should form in C1 and C2 type carbonaceous chondrites as functions of pressure and temperature. The results suggest that talc, antigorite plus or minus magnesite are the major volatile bearing phases and are stable below 400 C at 1 bar in these chondritic compositions. Simulated heating of a kilogram of C2 chondrite at fixed bulk composition between 400 and 800 C at 1 bar yields about 135 gm of volatile, which is made primarily of H2O, H2, CH4, CO2 and CO. The relative abundances of these volatile species change as functions of temperature, and on a molar basis, H2 becomes the most dominant species above 500 C. In contrast, Cl chondrites yield about 306 gm of volatile under the same condition, which consist almost completely of 60 wt percent H2O and 40 wt percent CO2. Preliminary kinetic considerations suggest that equilibrium dehydration of hydrous phyllosilicates should be attainable within a few hours at 600 C. These results provide the framework for further analyses of the volatile and economic resource potentials of carbonaceous chondrites.

Microscale Variations in the 13C Content of the Murchison Meteorite

NASA Astrophysics Data System (ADS)

Romanek, C.; Gibson, E.; Socki, R.; Burkett, P. J.

1993-07-01

Heretofore unresolved micrometer-scale carbon isotopic zonation in the Murchison meteorite (CM3) is documented using a laser microprobe mass spectrometer. High-resolution isotopic gradients and heterogeneities between high- and low-temperature textural components help to constrain the processes that have shaped the physiochemical character of this carbonaceous chondrite. Previous bulk samples of Murchison yield an average delta ^13C value of - 5.7 +/- 4.3 per mil [1] while individual components such as micrometer-sized mineral separates (e.g., C(sub)graphite , C(sub)diamond, and SiC), acid- soluble extracts (e.g., CaCO3 and polar hydrocarbons), and insoluble residues (e.g., polycyclic aromatic hydrocarbons) are isotopically diverse (delta ^13C of -1000 to 29,000 per mil). While these studies shed light on the origin and occurrence of C-bearing phases, they fail to constrain intrinsic spatial isotopic heterogeneities. The power of the laser microprobe lies in the fact that in situ chemical and isotopic compositions are measured simultaneously for volatiles extracted from extremely small sample volumes (i.e., 0.025 mm^3 for 5 wt% C). Nd-YAG laser irradiation (1.06 micrometers) is directed onto texturally defined targets (>=50 micrometers wide) from which solid material is volatilized. Condensible gaseous phases are collected in a variable-temperature cold trap while the more volatile species (CH4 and CO) are quantified using an ion trap mass spectrometer. All gases are then converted to CO2 in a CuO furnace (containing Pt) held at 600 degrees C and analyzed for carbon and oxygen isotope ratios. The concentration and isotopic composition of condensed species are determined by stepped sublimation of unstable components and conversion to CO2. Preliminary isotopic analyses of the total volatile C content (i.e., bulk microanalysis) from distinct textural components at least 0.05 mm^3 in volume are described below. The most ^13C-depleted components within Murchison reside within the cores of chondrules and/or aggregates. Three typical cores were analyzed, with an average bulk composition of -21.0 +/- 0.5 per mil (n = 7). The bulk ^13C content of C-bearing phases increases monotonically outward in all directions within 100 to 200 micrometers of each core (i.e., within dust mantles) to a constant matrix value of -12.5 +/- 0.5 per mil (n = 40). The most isotopically enriched textural component found in Murchison is a regolith breccia clast without chondrules that has an average bulk delta ^13C value of -10 +/-0.5 per mil (n = 5). The clast was originally detectable only under cathodoluminescence, but with the aid of the laser microprobe it is now characterized by an unusually low volatile content and enriched ^13C composition. In general, the most isotopically enriched components also produce the lowest yield of gas (normalized to sampling volume). This trend of isotopic enrichment from chondrule to matrix has been documented previously for oxygen isotopes in carbonaceous chondrites [2]. Carbon isotopic gradients and heterogeneities within Murchison reflect fundamental changes in the chemical speciation and/or isotopic content of the main C-bearing components (i.e., acid-soluble and insoluble hydrocarbon fractions) within the meteorite. Perhaps core interiors and dust mantles are responding to environmental changes reflected in the speciation of C-bearing species distributed within the solar nebula or the parent body. Inverse correlations between hydrocarbon atomic mass number and ^13C abundance in the acid-soluble [3] and insoluble residues [4] of Murchison have been documented. Alternatively, micrometer-scale isotopic gradients may reflect fundamental changes in the isotopic composition of individual C-bearing species through time. Enrichments may represent kinetically controlled processes related to hydrocarbon formation. In contrast, assuming an equilibrium fractionation mechanism, isotopic enrichments may record a temperature-dependent component to hydrocarbon delta ^13C values. These opposing alternatives will be discussed in light of the isotopic composition of individual C-bearing components volatilized from tightly constrained sample volumes within Murchison. References: [1] Kerridge J. F. (1985) GCA, 49, 1707-1714. [2] Clayton R. N. and Mayeda T. K. (1984) EPSL, 67, 151-161. [3] Yuen G. et al. (1984) Nature, 307, 254. [4] Gilmour I. et al. (1991) Meteoritics, 26, 337-338.

Volatile element depletion and K-39/K-41 fractionation in lunar soils

NASA Technical Reports Server (NTRS)

Church, S. E.; Tilton, G. R.; Wright, J. E.; Lee-Hu, C.-N.

1976-01-01

Evidence for selective loss and isotopic fractionation (in the case of K) of volatile elements during formation of agglutinates by micrometeoritic bombardment of lunar soils is presented. Concentrations and isotopic compositions of volatile elements (K, Rb, Pb) and nonvolatile elements (U, Th, Ba, Sr, rare earths) in separates taken from soils 14163, 14259, 15041, 68501, and 71500 are examined. Rayleigh fractionation calculations applied to K-39/K-41 isotopic data indicate ten-fold recycling of bulk soil, to account for observed isotopic anomalies. The lunar soil fines fraction seems to be a site of deposition for volatile or labile Pb produced during agglutination. Local fines (below 75 microns) are viewed as representative of the parent material for agglutinates formed in situ by micrometeoritic impact. Magnetic separation of agglutinates from soil 68501 revealed a bimodal population, with one class comprising welded blocky magnetic glasses.

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)

NASA Astrophysics Data System (ADS)

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.

Copper and Zinc isotope composition of CR, CB and CH-like meteorites.

NASA Astrophysics Data System (ADS)

Russell, S.; Zhu, X.; Guo, Y.; Mullane, E.; Gounelle, M.; Mason, T.; Coles, B.

2003-04-01

Copper and zinc isotopes have recently been shown to be variable in isotopic composi-tion among terrestrial and extraterrestrial materials [1-3]. For this study, we have se-lected samples (bulk meteorite and chondrule separates) from the CR meteorite clan: Bencubbin (CB), Renazzo (CR2), NWA 801 (CR2), and HaH237 (CH-like). These meteorites were selected because meteorites from this clan have experienced very little alteration since their initial formation [4] and for their extremely high refrac-tory/volatile element ratios. The latter characteristic may allow a test of the correlation observed by [2] between element ratios and Cu isotope composition. Measurements were performed on NHM/IC Micromass Isoprobe and Oxford Nu MC-ICP-MS using techniques described elsewhere [1,5]. Each of the meteorites measured so far for Cu and Zn are isotopically light compared to the terrestrial mantle. This suggests that the terrestrial value may have been altered from the pristine solar system value, or else there were multiple early solar system components. Zinc isotopic com-positions lie on a fractionation line and range from δ66ZnNIST = -1.4±0.1ppm (bulk NWA801) to -1.9±0.1ppm (separated chondrule, NWA 801). Copper isotope compositions vary from δ65CuNIST976 = -1.5±0.1ppm (bulk Renazzo) to -3.1±0.1ppm (separated chondrule, NWA 801). Two chondrules from NWA 801 have differing Cu isotope values (-3.1±0.1 and -2.0±0.1ppm) and both are lighter than the bulk meteorite (-1.9±0.1ppm), suggesting a lack of equilibration with respect to Cu in this meteorite. The light values for the two separated chondrules, compared the bulk meteorite, hints that chondrules may be isotopically lighter than co-existing matrix, metal and sulphides with respect to Cu. The copper isotope compositions are not as isotopically light as expected for the high refractory/volatile element ratio observed in these chondrites. Thus a model to account for the Cu isotopes in chondrites may require greater com-plexity than one involving simple mixing of two primordial components. References: [1] Zhu et al., Chem. Geol. 163,139-149 (2000). [2] Luck et al., GCA 67 143 (2002). [3] Luck et al., MAPS 35 A100 (2000) [4] Krot et al., MAPS 37 1451-1490 (2002) [5] Mason et al. EOS Trans. AGU abstract V21A-0966 82 (2001)

A volatile rich Earth's core?

NASA Astrophysics Data System (ADS)

Morard, G.; Antonangeli, D.; Andrault, D.; Nakajima, Y.

2017-12-01

The composition of the Earth's core is still an open question. Although mostly composed of iron, it contains impurities that lower its density and melting point with respect to pure Fe. Knowledge of the nature and abundance of light elements (O, S, Si, C or H) in the core has major implications for establishing the bulk composition of the Earth and for building the model of Earth's differentiation. Geochemical models of the Earth's formation point out that its building blocks were depleted in volatile elements compared to the chondritic abundance, therefore light elements such as S, H or C cannot be the major elements alloyed with iron in the Earth's core. However, such models should be compatible with the comparison of seismic properties of the Earth's core and physical properties of iron alloys under extreme conditions, such as sound velocity or density of solid and liquid. The present work will discuss the recent progress for compositional model issued from studies of phase diagrams and elastic properties of iron alloys under core conditions and highlight the compatibility of volatile elements with observed properties of the Earth's core, in potential contradiction with models derived from metal-silicate partitioning experiments.

40 CFR 60.502 - Standard for Volatile Organic Compound (VOC) emissions from bulk gasoline terminals.

Code of Federal Regulations, 2014 CFR

2014-07-01

... (VOC) emissions from bulk gasoline terminals. 60.502 Section 60.502 Protection of Environment... SOURCES Standards of Performance for Bulk Gasoline Terminals § 60.502 Standard for Volatile Organic Compound (VOC) emissions from bulk gasoline terminals. On and after the date on which § 60.8(a) requires a...

40 CFR 60.502 - Standard for Volatile Organic Compound (VOC) emissions from bulk gasoline terminals.

Code of Federal Regulations, 2012 CFR

2012-07-01

... (VOC) emissions from bulk gasoline terminals. 60.502 Section 60.502 Protection of Environment... SOURCES Standards of Performance for Bulk Gasoline Terminals § 60.502 Standard for Volatile Organic Compound (VOC) emissions from bulk gasoline terminals. On and after the date on which § 60.8(a) requires a...

40 CFR 60.502 - Standard for Volatile Organic Compound (VOC) emissions from bulk gasoline terminals.

Code of Federal Regulations, 2013 CFR

2013-07-01

... (VOC) emissions from bulk gasoline terminals. 60.502 Section 60.502 Protection of Environment... SOURCES Standards of Performance for Bulk Gasoline Terminals § 60.502 Standard for Volatile Organic Compound (VOC) emissions from bulk gasoline terminals. On and after the date on which § 60.8(a) requires a...

40 CFR 60.502 - Standard for Volatile Organic Compound (VOC) emissions from bulk gasoline terminals.

Code of Federal Regulations, 2011 CFR

2011-07-01

... (VOC) emissions from bulk gasoline terminals. 60.502 Section 60.502 Protection of Environment... SOURCES Standards of Performance for Bulk Gasoline Terminals § 60.502 Standard for Volatile Organic Compound (VOC) emissions from bulk gasoline terminals. On and after the date on which § 60.8(a) requires a...

40 CFR 60.502 - Standard for Volatile Organic Compound (VOC) emissions from bulk gasoline terminals.

Code of Federal Regulations, 2010 CFR

2010-07-01

... (VOC) emissions from bulk gasoline terminals. 60.502 Section 60.502 Protection of Environment... SOURCES Standards of Performance for Bulk Gasoline Terminals § 60.502 Standard for Volatile Organic Compound (VOC) emissions from bulk gasoline terminals. On and after the date on which § 60.8(a) requires a...

METHANE AND NITROGEN ABUNDANCES ON PLUTO AND ERIS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tegler, S. C.; Cornelison, D. M.; Abernathy, M. R.

We present spectra of Eris from the MMT 6.5 m Telescope and Red Channel Spectrograph (5700-9800 A, 5 A pixel{sup -1}) on Mt. Hopkins, AZ, and of Pluto from the Steward Observatory 2.3 m Telescope and Boller and Chivens Spectrograph (7100-9400 A, 2 A pixel{sup -1}) on Kitt Peak, AZ. In addition, we present laboratory transmission spectra of methane-nitrogen and methane-argon ice mixtures. By anchoring our analysis in methane and nitrogen solubilities in one another as expressed in the phase diagram of Prokhvatilov and Yantsevich, and comparing methane bands in our Eris and Pluto spectra and methane bands in ourmore » laboratory spectra of methane and nitrogen ice mixtures, we find Eris' bulk methane and nitrogen abundances are {approx}10% and {approx}90% and Pluto's bulk methane and nitrogen abundances are {approx}3% and {approx}97%. Such abundances for Pluto are consistent with values reported in the literature. It appears that the bulk volatile composition of Eris is similar to the bulk volatile composition of Pluto. Both objects appear to be dominated by nitrogen ice. Our analysis also suggests, unlike previous work reported in the literature, that the methane and nitrogen stoichiometry is constant with depth into the surface of Eris. Finally, we point out that our Eris spectrum is also consistent with a laboratory ice mixture consisting of 40% methane and 60% argon. Although we cannot rule out an argon-rich surface, it seems more likely that nitrogen is the dominant species on Eris because the nitrogen ice 2.15 {mu}m band is seen in spectra of Pluto and Triton.« less

Chondritic models of 4 Vesta: Implications for geochemical and geophysical properties

NASA Astrophysics Data System (ADS)

Toplis, M. J.; Mizzon, H.; Monnereau, M.; Forni, O.; McSween, H. Y.; Mittlefehldt, D. W.; McCoy, T. J.; Prettyman, T. H.; De Sanctis, M. C.; Raymond, C. A.; Russell, C. T.

2013-11-01

Simple mass-balance and thermodynamic constraints are used to illustrate the potential geochemical and geophysical diversity of a fully differentiated Vesta-sized parent body with a eucrite crust (e.g., core size and density, crustal thickness). The results of this analysis are then combined with data from the howardite-eucrite-diogenite (HED) meteorites and the Dawn mission to constrain Vesta's bulk composition. Twelve chondritic compositions are considered, comprising seven carbonaceous, three ordinary, and two enstatite chondrite groups. Our analysis excludes CI and LL compositions as plausible Vesta analogs, as these are predicted to have a negative metal fraction. Second, the MELTS thermodynamic calculator is used to show that the enstatite chondrites, the CV, CK and L-groups cannot produce Juvinas-like liquids, and that even for the other groups, depletion in sodium is necessary to produce liquids of appropriate silica content. This conclusion is consistent with the documented volatile-poor nature of eucrites. Furthermore, carbonaceous chondrites are predicted to have a mantle too rich in olivine to produce typical howardites and to have Fe/Mn ratios generally well in excess of those of the HEDs. On the other hand, an Na-depleted H-chondrite bulk composition is capable of producing Juvinas-like liquids, has a mantle rich enough in pyroxene to produce abundant howardite/diogenite, and has a Fe/Mn ratio compatible with eucrites. In addition, its predicted bulk-silicate density is within 100 kg m-3 of solutions constrained by data of the Dawn mission. However, oxidation state and oxygen isotopes are not perfectly reproduced and it is deduced that bulk Vesta may contain approximately 25% of a CM-like component. Values for the bulk-silicate composition of Vesta and a preliminary phase diagram are proposed.

From Dust to Planets: The Tale Told by Moderately Volatile Element Depletion (MOVED)

NASA Technical Reports Server (NTRS)

Yin, Qing-Zhu

2004-01-01

The pronounced depletion of moderately volatile elements (MOVE, that condense or evaporate at temperatures in the range 1350-650K) relative to the average solar composition is a characteristic feature in most primitive chondrites and bulk terrestrial planets. It differs from the composition of the Sun and from the materials further away from the Sun (CI chondrites). None of the remaining planets or even meteorites shows an enrichment of volatile elements that would balance the depletion in the inner Solar System. Whether this depletion occurred in solar nebular stage or in planetary formation stage has been the subject of long lasting debate. The search for mysterite initiated in 1973 continues today in search of lost planets. Here I show that the MOVED patterns demonstrate a clear connection between the rocky materials of the inner solar system and the interstellar dust. The inheritance of interstellar materials by the solar system is not only documented by the presence of presolar grains, various isotopic anomalies, but also expressed in the chemical element distribution in the inner solar system.

A multi-component evaporation model for beam melting processes

NASA Astrophysics Data System (ADS)

Klassen, Alexander; Forster, Vera E.; Körner, Carolin

2017-02-01

In additive manufacturing using laser or electron beam melting technologies, evaporation losses and changes in chemical composition are known issues when processing alloys with volatile elements. In this paper, a recently described numerical model based on a two-dimensional free surface lattice Boltzmann method is further developed to incorporate the effects of multi-component evaporation. The model takes into account the local melt pool composition during heating and fusion of metal powder. For validation, the titanium alloy Ti-6Al-4V is melted by selective electron beam melting and analysed using mass loss measurements and high-resolution microprobe imaging. Numerically determined evaporation losses and spatial distributions of aluminium compare well with experimental data. Predictions of the melt pool formation in bulk samples provide insight into the competition between the loss of volatile alloying elements from the irradiated surface and their advective redistribution within the molten region.

The provenances of asteroids, and their contributions to the volatile inventories of the terrestrial planets.

PubMed

Alexander, C M O'D; Bowden, R; Fogel, M L; Howard, K T; Herd, C D K; Nittler, L R

2012-08-10

Determining the source(s) of hydrogen, carbon, and nitrogen accreted by Earth is important for understanding the origins of water and life and for constraining dynamical processes that operated during planet formation. Chondritic meteorites are asteroidal fragments that retain records of the first few million years of solar system history. The deuterium/hydrogen (D/H) values of water in carbonaceous chondrites are distinct from those in comets and Saturn's moon Enceladus, implying that they formed in a different region of the solar system, contrary to predictions of recent dynamical models. The D/H values of water in carbonaceous chondrites also argue against an influx of water ice from the outer solar system, which has been invoked to explain the nonsolar oxygen isotopic composition of the inner solar system. The bulk hydrogen and nitrogen isotopic compositions of CI chondrites suggest that they were the principal source of Earth's volatiles.

Gallium isotopic evidence for the fate of moderately volatile elements in planetary bodies and refractory inclusions

NASA Astrophysics Data System (ADS)

Kato, Chizu; Moynier, Frédéric

2017-12-01

The abundance of moderately volatile elements, such as Zn and Ga, show variable depletion relative to CI between the Earth and primitive meteorite (chondrites) parent bodies. Furthermore, the first solar system solids, the calcium-aluminum-rich inclusions (CAIs), are surprisingly rich in volatile element considering that they formed under high temperatures. Here, we report the Ga elemental and isotopic composition of a wide variety of chondrites along with five individual CAIs to understand the origin of the volatile elements and to further characterize the enrichment of the volatile elements in high temperature condensates. The δ71Ga (permil deviation of the 71Ga/69Ga ratio from the Ga IPGP standard) of carbonaceous chondrites decreases in the order of CI >CM >CO >CV and is inversely correlated with the Al/Ga ratio. This implies that the Ga budget of the carbonaceous chondrites parent bodies were inherited from a two component mixing of a volatile rich reservoir enriched in heavy isotope of Ga and a volatile poor reservoir enriched in light isotope of Ga. Calcium-aluminum-rich inclusions are enriched in Ga and Zn compared to the bulk meteorite and are both highly isotopically fractionated with δ71Ga down to -3.56‰ and δ66Zn down to -0.74‰. The large enrichment in the light isotopes of Ga and Zn in the CAIs implies that the moderately volatile elements were introduced in the CAIs during condensation in the solar nebula as opposed to secondary processing in the meteorite parent body and supports a change in gas composition in which CAIs were formed.

On the Impact Origin of Phobos and Deimos. IV. Volatile Depletion

NASA Astrophysics Data System (ADS)

Hyodo, Ryuki; Genda, Hidenori; Charnoz, Sébastien; Pignatale, Francesco C. F.; Rosenblatt, Pascal

2018-06-01

Recent works have shown that the Martian moons Phobos and Deimos may have accreted within a giant impact-generated disk whose composition is about an equal mixture of Martian material and impactor material. Just after the giant impact, the Martian surface heated up to ∼3000–6000 K and the building blocks of moons, including volatile-rich vapor, were heated up to ∼2000 K. In this paper, we investigate the volatile loss from the building blocks of Phobos and Deimos by hydrodynamic escape of vapor and radiation pressure on condensed particles. We show that a non-negligible amount of volatiles (>10% of the vapor with temperature >1000 K via hydrodynamic escape, and moderately volatile dusts that condense at ∼700–2000 K via radiation pressure) could be removed just after the impact during their first single orbit from their pericenters to apocenters. Our results indicate that bulk Phobos and Deimos are depleted in volatile elements. Together with future explorations such as the Japan Aerospace eXploration Agency’s Martian Moons eXploration mission, our results could be used to constrain the origin of Phobos and Deimos.

Questionable inheritance: What Processes on Planetesimals Mean for the Bulk Composition of the Earth

NASA Astrophysics Data System (ADS)

Elkins-Tanton, L. T.

2015-12-01

Interrogating Earth's interior is limited to indirect means, such as seismic or magnetic fields, and relies heavily on modeling. A large body of literature either attempts to constrain the composition of the deep mantle by mass balancing the Earth with a chondritic composition, or to demonstrate that the Earth does not have a chondritic composition. These models provide predictions for the composition and density of the ultra-low shear wave provinces and for the D" layer, among others, and compare their results to structures resulting from seismic studies. The bulk composition of the Earth, however, remains an open question. We now know that the planets accreted from embryos that were already differentiated. The complexity of processes that occurred on planetesimals and planetary embryos are just beginning to come to light. Heating by radiogenic 26Al likely produced waves of hydration and dehydration in planetesimals. These free fluids may have carried a wide range of volatiles, moving them from the interior to the lid, or even losing them to space. Simultaneously, the first free fluids may have reacted with metals, producing oxides or sulfides. Further heating is required to reduce these to metals and made core formation possible; or perhaps the earliest cores are not fully metallic. These planetesimals and the embryos they were growing into were subjected to a series of impacts. As the work of Asphaug and his group have demonstrated, some of these are accretionary impacts, and some are hit-and-run, or destructive impacts. These destructive impacts may have reduced the thickness of Mercury's mantle, and stripped the mantle off the metal asteroid Psyche. Where, then would the shattered silicates from such collisions go? Asphuag suggests that at least in part they are added to the growing terrestrial planets. If the planetesimals and planetary embryos were compositionally heterogeneous because of interior fluid and magma movement, then the silicates blown off them by impacts would not have a bulk chondritic composition. The growing planets would not then have a bulk chondritic composition. This talk will discuss the possible ramifications of this model and its application to bulk Earth models.

Constraining the volatile budget of the lunar interior

NASA Astrophysics Data System (ADS)

Potts, N. J.; Bromiley, G. D.

2017-12-01

Measurements of volatiles (F, Cl, S, H2O) in a range of lunar samples confirm the presence of volatile material in lunar magmas. It remains unknown, however, where this volatile material is stored and when it was delivered to the Moon. On Earth, point defects within mantle olivine, and its high-pressure polymorphs, are thought to be the largest reservoir of volatile material. However, as volatiles have been cycled into and out of the Earth's mantle throughout geological time, via subduction and volcanism, this masks any original volatile signatures. As the Moon has no plate tectonics, it is expected that any volatile material present in the deep lunar interior would have been inherited during accretion and differentiation, providing insight into the delivery of volatiles to the early Earth-Moon system. Our aim was, therefore, to test the volatile storage capacity of the deep lunar mantle and determine mineral/melt partitioning for key volatiles. Experiments were performed in a primitive lunar mantle composition and run at relevant T, P, and at fO2 below the IW buffer. Experiments replicated the initial stages of LMO solidification with either olivine + melt, olivine + pyroxene + melt, or pyroxene + melt as the only phases present. Mineral-melt partition coefficients (Dx) derived for volatile material (F, Cl, S, H2O) vary significantly compared to those derived for terrestrial conditions. An order of magnitude more H2O was found to partition into lunar olivine compared to the terrestrial upper mantle. DF derived for lunar olivine are comparable to the highest terrestrial derived values whilst no Cl was found to partition into lunar olivine under these conditions. Furthermore, an inverse trend between DF and DOH hints towards coupled-substitution mechanisms between H and F under low-fO2/lunar bulk composition. These results suggest that if volatile material was present in the LMO a significant proportion could be partitioned into the lower lunar mantle. The implications of this are not only important for understanding the behaviour of volatiles during planetary differentiation but would impact any future seismic study of the Moon.

Chemical composition of Mars

USGS Publications Warehouse

Morgan, J.W.; Anders, E.

1979-01-01

The composition of Mars has been calculated from the cosmochemical model of Ganapathy and Anders (1974) which assumes that planets and chondrites underwent the same 4 fractionation processes in the solar nebula. Because elements of similar volatility stay together in these processes, only 4 index elements (U, Fe, K and Tl or Ar36) are needed to calculate the abundances of all 83 elements in the planet. The values chosen are U = 28 ppb, K = 62 ppm (based on K U = 2200 from orbital ??-spectrometry and on thermal history calculations by Tokso??z and Hsui (1978) Fe = 26.72% (from geophysical data), and Tl = 0.14 ppb (from the Ar36 and Ar40 abundances measured by Viking). The mantle of Mars is an iron-rich [Mg/(Mg + Fe) = 0.77] garnet wehrlite (?? = 3.52-3.54 g/cm3), similar to McGetchin and Smyth's (1978) estimate but containing more Ca and Al. It is nearly identical to the bulk Moon composition of Morgan et al. (1978b). The core makes up 0.19 of the planet and contains 3.5% S-much less than estimated by other models. Volatiles have nearly Moon-like abundances, being depleted relative to the Earth by factors of 0.36 (K-group, Tcond = 600-1300 K) or 0.029 (Tl group, Tcond < 600 K). The water abundance corresponds to a 9 m layer, but could be higher by as much as a factor of 11. Comparison of model compositions for 5 differentiated planets (Earth, Venus, Mars, Moon, and eucrite parent body) suggests that volatile depletion correlates mainly with size rather than with radial distance from the Sun. However, the relatively high volatile content of shergottites and some chondrites shows that the correlation is not simple; other factors must also be involved. ?? 1979.

Relationships between Microbial Activities and Subduction-related Outgassing and Volatile Flux at Aleutian Arc Volcanoes

NASA Astrophysics Data System (ADS)

Miller, H.; Lopez, T. M.; Fischer, T. P.; Schrenk, M. O.

2016-12-01

Subduction-related processes, including the movement and alteration of carbon compounds, are an important component of global geochemical cycles. Actively degassing volcanoes of the Aleutian Island arc offer interesting opportunities to not only characterize the composition and abundance of volatiles, but also to identify the origin of the discharging gases (e.g. mantle, organic matter, or carbonates). Taking this approach a step further, microbial activities in and around volcanic fumarole areas may impact the composition and flux of reduced volcanic gases, either through their modification or their assimilation into fixed biomass. Microbiological studies of these systems can be used to develop predictive models to complement those based upon geochemical data while providing greater understanding of the causal relationships between microbial populations and their environment, and ultimately refine estimates of volcanic outgassing. Coupled fumarole soil and gas samples were collected from several Aleutian Island volcanoes in 2015 (Gareloi, Kanaga, Kiska, Little Sitkin) and 2016 (Okmok, Resheschnoi). DNA was extracted from the soil and used to describe microbial community composition, while gas samples were analyzed through chromatography and mass spectrometry. Preliminary data suggests a relationship between the abundance of specific groups of prokaryotes known to metabolize reduced gases, such as sulfur-oxidizers and methanotrophs, and the abundances of the degassing volatiles, including sulfur dioxide and methane. Ongoing studies aimed at investigating the relationship between the genomic composition of the fumarolic microbial community and the physical and chemical properties of the soil (i.e. mineralogy, bulk geochemistry, nutrient concentration, gas flux, and environmental measurements) are underway. These data will be used to evaluate the potential for microbial communities to remove volcanic carbon and store it as biomass, or to modify the volatile carbon flux through metabolic activities. When holistically considered, these data will help to refine estimates of volatile flux and outgassing from the Aleutian Arc, particularly those involving carbon compounds, and potentially provide a novel predictive tool that can be applied in high throughput to volcanoes worldwide.

Mass Spectrometry in Jupiter's Atmosphere: Vertical Variation of Volatile Vapors

NASA Astrophysics Data System (ADS)

Wong, Michael H.; Atreya, Sushil K.; Mahaffy, Paul R.

2014-05-01

The Galileo Probe made the first and only in situ measurements of composition in Jupiter's atmosphere, led by the Galileo Probe Mass Spectrometer, or GPMS [1]. The major contribution from this instrument was the measurement of abundances and isotope ratios of the noble gases, as well as the volatile gases CH4, NH3, H2O, and H2S [2,3]. These initial results were further refined by detailed laboratory calibrations for the noble gases [4] and the volatiles [5]. The probe measurements resulted in the first determination of the heavy element abundances (except carbon that was known previously) and He/H ratio, which provide critical constraints to models of the formation of Jupiter and the origin of its atmosphere [6,7]. The condensable volatiles, or CVs (ammonia, H2S, and water), increased with depth in the probe entry site. This vertical variation was observed at levels much deeper than the modeled cloud bases, as predicted by one-dimensional chemical equilibrium models. The discrepancy is due to the probe's entry into a dry region known as a 5-μm hot spot. The 5-μm hot spots are part of an atmospheric wave system that encircles Jupiter just north of the equator. Despite the anomalous meteorology, the bulk abundances of NH3 and H2S were measured by the probe, and found to be enriched with respect to solar composition (similarly to the non-condensable volatile CH4). The deepest water mixing ratio, however, was observed to be depleted relative to solar composition. We review an updated context for the CV vertical profiles measured by the GPMS, based on the latest results from remote sensing, simulation, and reinterpretation of Galileo Probe measurements. In particular, we find that (1) the bulk abundance of water in Jupiter's atmosphere must be greater than the subsolar abundance derived from the deepest GPMS measurements [8], and that (2) CV mixing ratios are controlled by a range of processes in addition to condensation of the ices NH3, NH4SH, and H2O [5-9]. Both bulk abundances and spatial variation of these species will be further constrained by the Juno mission, scheduled to arrive at Jupiter in 2016. References: [1] Niemann, H.B. et al. 1992, SSRv 60, 111-142 [2] Niemann, H.B. et al. 1996, Science 272, 846-849 [3] Niemann, H.B. et al. 1998, JGR 103, 22831-22845 [4] Mahaffy, P.R. et al. 2000, JGR 105, 15061-15071 [5] Wong, M.H. et al. 2004, Icarus 171, 153-170 [6] Atreya, S.K. et al., 1999, Planet. Space Sci. 47, 1243-1262 [7] Atreya, S.K. et al., 2003, Planet. Space Sci. 451, 105-112 [8] Wong, M.H. et al., 2008, in Reviews in Mineralogy and Geochemistry, vol. 68. Mineralogical Society of America, Chantilly, VA, pp. 219-246 [9] Wong, M.H., 2009, Icarus 199, 231-235

Potassium isotopic evidence for a high-energy giant impact origin of the Moon.

PubMed

Wang, Kun; Jacobsen, Stein B

2016-10-27

The Earth-Moon system has unique chemical and isotopic signatures compared with other planetary bodies; any successful model for the origin of this system therefore has to satisfy these chemical and isotopic constraints. The Moon is substantially depleted in volatile elements such as potassium compared with the Earth and the bulk solar composition, and it has long been thought to be the result of a catastrophic Moon-forming giant impact event. Volatile-element-depleted bodies such as the Moon were expected to be enriched in heavy potassium isotopes during the loss of volatiles; however such enrichment was never found. Here we report new high-precision potassium isotope data for the Earth, the Moon and chondritic meteorites. We found that the lunar rocks are significantly (>2σ) enriched in the heavy isotopes of potassium compared to the Earth and chondrites (by around 0.4 parts per thousand). The enrichment of the heavy isotope of potassium in lunar rocks compared with those of the Earth and chondrites can be best explained as the result of the incomplete condensation of a bulk silicate Earth vapour at an ambient pressure that is higher than 10 bar. We used these coupled constraints of the chemical loss and isotopic fractionation of K to compare two recent dynamic models that were used to explain the identical non-mass-dependent isotope composition of the Earth and the Moon. Our K isotope result is inconsistent with the low-energy disk equilibration model, but supports the high-energy, high-angular-momentum giant impact model for the origin of the Moon. High-precision potassium isotope data can also be used as a 'palaeo-barometer' to reveal the physical conditions during the Moon-forming event.

Asteroid resources

NASA Technical Reports Server (NTRS)

Lewis, John S.

1992-01-01

There are three types of possible asteroidal materials that appear to be attractive for exploitation: (1) volatiles, (2) free metals, and (3) bulk dirt. Because some of the near-Earth asteroids are energetically more accessible than the Moon (require a round-trip total change in velocity less than 9 km/sec, though the trip time would be measured in years not days), such an asteroid might be chosen as the source of any useful material, even if that material was also available on the Moon. Provided that the asteroid was minable, it might therefore be chosen as the source of bulk dirt needed for shielding in low Earth orbit (LEO) or elsewhere in near-Earth space. And the near-Earth asteroids may offer materials that are rare or absent on the surface of the Moon. The relationship between asteroids and meteorites is discussed. A brief overview of the entire range of meteorite compositions, with emphasis on the occurrence of interesting resources is presented. Focus is on materials useful in space, especially volatiles, metals, and raw dirt. Those few materials that may have sufficiently high market value to be worth returning to Earth will be mentioned.

Chemical Composition of the Semi-Volatile Grains of Comet 67P/Churyumov-Gerasimenko

NASA Astrophysics Data System (ADS)

Wurz, P.; Altwegg, K.; Balsiger, H. R.; Berthelier, J. J.; De Keyser, J.; Fiethe, B.; Fuselier, S. A.; Gasc, S.; Gombosi, T. I.; Korth, A.; Mall, U.; Reme, H.; Rubin, M.; Tzou, C. Y.

2017-12-01

Rosetta was in orbit of comet 67P/Churyumov-Gerasimenko from August 2014 to September 2016. On board is the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) experiment that has been continuously collecting data on the chemical composition and activity of the coma from 3.5 AU to pericentre at 1.24 AU and out again to 3.5 AU. ROSINA consists of two mass spectrometers, the Double Focusing Mass Spectrometer (DFMS) and the Reflectron-type Time-Of-Flight (RTOF), as well as the COmet Pressure Sensor (COPS). ROSINA recorded the neutral gas and thermal plasma in the comet's coma. The two mass spectrometers have high dynamic ranges and complement each other with high mass resolution, and high time resolution and large mass range. COPS measures total gas densities, bulk velocities, and gas temperatures. Occasionally, a dust grain of cometary origin enters the ion source of a ROSINA instrument where the volatile part evaporates since these ion sources are hot. The release of volatiles from cometary dust grains was observed with all three ROSINA instruments on several occasions. Because the volatile content of such a dust grain is completely evaporated after a few seconds, the RTOF instrument is best suited for the investigation of its chemical composition since complete mass spectra are recorded during this time. During the mission 9 dust grains were observed with RTOF during the October 2014 to July 2016 time period. It is estimated that these grains contain about 10-15 g of volatiles. The mass spectra were interpreted with a set of 75 molecules, with the major groups of chemical species being hydrocarbons, oxygenated hydrocarbons, nitrogen-bearing molecules, sulphur-bearing molecules, halogenated molecules and others. About 70% of these grains are depleted in water compared to the comet coma, thus, can be considered as semi-volatile dust grains, and the other about 30% are water grains. The chemical composition varies considerably from grain to grain, indicating large chemical heterogeneity at these scales. In contrast, the elemental abundances vary much less.

Early inner solar system origin for anomalous sulfur isotopes in differentiated protoplanets.

PubMed

Antonelli, Michael A; Kim, Sang-Tae; Peters, Marc; Labidi, Jabrane; Cartigny, Pierre; Walker, Richard J; Lyons, James R; Hoek, Joost; Farquhar, James

2014-12-16

Achondrite meteorites have anomalous enrichments in (33)S, relative to chondrites, which have been attributed to photochemistry in the solar nebula. However, the putative photochemical reactions remain elusive, and predicted accompanying (33)S depletions have not previously been found, which could indicate an erroneous assumption regarding the origins of the (33)S anomalies, or of the bulk solar system S-isotope composition. Here, we report well-resolved anomalous (33)S depletions in IIIF iron meteorites (<-0.02 per mil), and (33)S enrichments in other magmatic iron meteorite groups. The (33)S depletions support the idea that differentiated planetesimals inherited sulfur that was photochemically derived from gases in the early inner solar system (<∼2 AU), and that bulk inner solar system S-isotope composition was chondritic (consistent with IAB iron meteorites, Earth, Moon, and Mars). The range of mass-independent sulfur isotope compositions may reflect spatial or temporal changes influenced by photochemical processes. A tentative correlation between S isotopes and Hf-W core segregation ages suggests that the two systems may be influenced by common factors, such as nebular location and volatile content.

Kinetic multi-layer model of aerosol surface and bulk chemistry (KM-SUB): the influence of interfacial transport and bulk diffusion on the oxidation of oleic acid by ozone

NASA Astrophysics Data System (ADS)

Shiraiwa, Manabu; Pfrang, Christian; Pöschl, Ulrich

2010-05-01

Aerosols are ubiquitous in the atmosphere and have strong effects on climate and public health. Gas-particle interactions can significantly change the physical and chemical properties of aerosols such as toxicity, reactivity, hygroscopicity and radiative properties. Chemical reactions and mass transport lead to continuous transformation and changes in the composition of atmospheric aerosols ("chemical aging"). Resistor model formulations are widely used to describe and investigate heterogeneous reactions and multiphase processes in laboratory, field and model studies of atmospheric chemistry. The traditional resistor models, however, are usually based on simplifying assumptions such as steady state conditions, homogeneous mixing, and limited numbers of non-interacting species and processes. In order to overcome these limitations, Pöschl, Rudich and Ammann have developed a kinetic model framework (PRA framework) with a double-layer surface concept and universally applicable rate equations and parameters for mass transport and chemical reactions at the gas-particle interface of aerosols and clouds [1]. Based on the PRA framework, we present a novel kinetic multi-layer model that explicitly resolves mass transport and chemical reaction at the surface and in the bulk of aerosol particles (KM-SUB) [2]. The model includes reversible adsorption, surface reactions and surface-bulk exchange as well as bulk diffusion and reaction. Unlike earlier models, KM-SUB does not require simplifying assumptions about steady-state conditions and radial mixing. The temporal evolution and concentration profiles of volatile and non-volatile species at the gas-particle interface and in the particle bulk can be modeled along with surface concentrations and gas uptake coefficients. In this study we explore and exemplify the effects of bulk diffusion on the rate of reactive gas uptake for a simple reference system, the ozonolysis of oleic acid particles, in comparison to experimental data and earlier model studies. We demonstrate how KM-SUB can be used to interpret and analyze experimental data from laboratory studies, and how the results can be extrapolated to atmospheric conditions. In particular, we show how interfacial transport and bulk transport, i.e., surface accommodation, bulk accommodation and bulk diffusion, influence the kinetics of the chemical reaction. Sensitivity studies suggest that in fine air particulate matter oleic acid and compounds with similar reactivity against ozone (C=C double bonds) can reach chemical life-times of multiple hours only if they are embedded in a (semi-)solid matrix with very low diffusion coefficients (~10-10 cm2 s-1). Depending on the complexity of the investigated system, unlimited numbers of volatile and non-volatile species and chemical reactions can be flexibly added and treated with KM-SUB. We propose and intend to pursue the application of KM-SUB as a basis for the development of a detailed master mechanism of aerosol chemistry as well as for the derivation of simplified but realistic parameterizations for large-scale atmospheric and climate models. References [1] Pöschl et al., Atmos. Chem. and Phys., 7, 5989-6023 (2007). [2] Shiraiwa et al., Atmos. Chem. Phys. Discuss., 10, 281-326 (2010).

Isotopes and Minor Volatiles in the Coma of Comet 67P/Churyumov-Gerasimenko Observed by the Rosetta/ROSINA Instrument: Planetary Implications

NASA Astrophysics Data System (ADS)

Marty, B.; Altwegg, K.; Balsiger, H. R.; Calmonte, U.; Hässig, M.; Le Roy, L.; Rubin, M.; Bieler, A. M.; Fuselier, S. A.; De Keyser, J. M.; Mousis, O.

2015-12-01

The Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) instrument suite is part of the payload of the European Space Agency's Rosetta spacecraft. Part of this suite, the Double Focusing Mass Spectrometer (DFMS) has been analyzing major (e.g., H2O,) as well as minor (CO, CO2, N2, NHx, noble gases) species and elements and some of their isotopes thanks to its high mass resolution of 3,000 at 1% peak height and its high sensitivity. In parallel to the presentation by Rubin et al. (this meeting) who discuss temporal variation of the coma composition as a function of heliospheric distance, we present here the on-going measurements done on the above species and isotopes. Besides temporal variability, one of the goals of ROSINA is to document the composition of cometary volatiles in the context of the formation of planets and of the origin of atmospheres. The first detection of a noble gas, Ar, in a cometary coma (Balsiger et al, in press), together with the measured D/H isotope ratio and carbon species, constrains the origin of the inner planet atmospheres and the terrestrial oceans. Assuming that 67P is representative of the cometary reservoir, major volatiles (H, C, N) of the inner planets are unlikely to have originated from comets, but a cometary origin for atmospheric noble gases is a viable hypothesis. However, these cometary measurements were done during a short interval of time (in autumn 2014) when the comet was at 3.5 AU from the Sun, which raises the question of how well they represent the bulk cometary composition. Further measurements of the bulk composition are planned close to the perihelion. Also of interest is the isotope composition of nitrogen in N-bearing compounds. Spectroscopic measurements of cometary HCN and NH2+ done so far indicate a two-fold enrichment in 15N, that needs to be confirmed by in-situ mass spectrometry. Measurements of other noble gases, in particular Xe (a very difficult measurement), may set stringent constraints on the nature (clathrate vs. amorphous) of cometary ice. Results from these measurements before and after the perihelion will be presented.

The thermal evolution and dynamo generation of Mercury with an Fe-Si core

NASA Astrophysics Data System (ADS)

Knibbe, Jurrien

2017-04-01

The present day partially liquid (as opposed to fully solidified) Fe-rich core of Mercury is traditionally explained by assuming a substantial amount of S to be present in the core (e.g. Grott et al., 2011), because S lowers the core's melting temperature. However, this assumption has problematic implications: Mercury's large Fe-rich core and measured low FeO surface content are indicative of an oxygen poor bulk composition, which is consistent with the volatile-poor material that is expected to have condensed from the solar nebula close to the Sun. In contrast, S is a moderately volatile element. Combined with the high S content of Mercury's crust and (likely) mantle, as indicated by the measured high S/Si surface fraction, the resulting high planetary S abundance is difficult to reconcile with a volatile poor origin of the planet. Additionally, the observed low magnetic field strength is most easily explained if compositional buoyancy fluxes are absent [Manglik et al., 2010], yet such fluxes are produced upon solidifying a pure Fe inner core from Fe-S liquid. Alternatively, both Mercury's high S/Si and Mg/Si surface ratios (Nittler et al., 2011) may indicate that a siderophile fractionation of Si and lithophile fractionation of S took place during Mercury's core-mantle differentiation. This fractionation behaviour of these elements is supported by metal/silicate partitioning experiments that have been performed at the low oxygen conditions inferred for Mercury [e.g. Chabot et al., 2014]. Mercury's bulk composition, in terms of S/Si and Fe/Si ratios, would also approach that of meteorites that are considered as potential building blocks of the planet if the core is Si-rich and S-poor. Here we simulate the thermal evolution of Mercury with an Fe-Si core. Results show that an Fe-Si core can remain largely molten until present, without the need for S. An Fe-Si core also has interesting implications for Mercury's core-convection regime and magnetic field generation. The non-preferential Si fractionation between solid and liquid metal does not produce a compositional gradient, such that compositional buoyancy fluxes are negligible. Additionally, thermally driven core convection is more efficient as a result of a high latent heat release upon solidifying Si-rich metal. Implications of this scenario for Mercury's magnetic field strength and geometry need to be further examined.

Implications of the observed Pluto-Charon density contrast

NASA Astrophysics Data System (ADS)

Bierson, C. J.; Nimmo, F.; McKinnon, W. B.

2018-07-01

Observations by the New Horizons spacecraft have determined that Pluto has a larger bulk density than Charon by 153 ± 44 kg m-3 (2σ uncertainty). We use a thermal model of Pluto and Charon to determine if this density contrast could be due to porosity variations alone, with Pluto and Charon having the same bulk composition. We find that Charon can preserve a larger porous ice layer than Pluto due to its lower gravity and lower heat flux but that the density contrast can only be explained if the initial ice porosity is ≳ 30%, extends to ≳100 km depth and Pluto retains a subsurface ocean today. We also find that other processes such as a modern ocean on Pluto, self-compression, water-rock interactions, and volatile (e.g., CO) loss cannot, even in combination, explain this difference in density. Although an initially high porosity cannot be completely ruled out, we conclude that it is more probable that Pluto and Charon have different bulk compositions. This difference could arise either from forming Charon via a giant impact, or via preferential loss of H2O on Pluto due to heating during rapid accretion.

Carbonate-derived CO 2 purging magma at depth: Influence on the eruptive activity of Somma-Vesuvius, Italy

NASA Astrophysics Data System (ADS)

Dallai, Luigi; Cioni, Raffaello; Boschi, Chiara; D'Oriano, Claudia

2011-10-01

Mafic phenocrysts from selected products of the last 4 ka volcanic activity at Mt. Vesuvius were investigated for their chemical and O-isotope composition, as a proxy for primary magmas feeding the system. 18O/ 16O ratios of studied Mg-rich olivines suggest that near-primary shoshonitic to tephritic melts experienced a flux of sedimentary carbonate-derived CO 2, representing the early process of magma contamination in the roots of the volcanic structure. Bulk carbonate assimilation (physical digestion) mainly occurred in the shallow crust, strongly influencing magma chamber evolution. On a petrological and geochemical basis the effects of bulk sedimentary carbonate digestion on the chemical composition of the near-primary melts are resolved from those of carbonate-released CO 2 fluxed into magma. An important outcome of this process lies in the effect of external CO 2 in changing the overall volatile solubility of the magma, enhancing the ability of Vesuvius mafic magmas to rapidly rise and explosively erupt at the surface.

Volatile element loss during planetary magma ocean phases

NASA Astrophysics Data System (ADS)

Dhaliwal, Jasmeet K.; Day, James M. D.; Moynier, Frédéric

2018-01-01

Moderately volatile elements (MVE) are key tracers of volatile depletion in planetary bodies. Zinc is an especially useful MVE because of its generally elevated abundances in planetary basalts, relative to other MVE, and limited evidence for mass-dependent isotopic fractionation under high-temperature igneous processes. Compared with terrestrial basalts, which have δ66Zn values (per mille deviation of the 66Zn/64Zn ratio from the JMC-Lyon standard) similar to some chondrite meteorites (∼+0.3‰), lunar mare basalts yield a mean δ66Zn value of +1.4 ± 0.5‰ (2 st. dev.). Furthermore, mare basalts have average Zn concentrations ∼50 times lower than in typical terrestrial basaltic rocks. Late-stage lunar magmatic products, including ferroan anorthosite, Mg- and Alkali-suite rocks have even higher δ66Zn values (+3 to +6‰). Differences in Zn abundance and isotopic compositions between lunar and terrestrial rocks have previously been interpreted to reflect evaporative loss of Zn, either during the Earth-Moon forming Giant Impact, or in a lunar magma ocean (LMO) phase. To explore the mechanisms and processes under which volatile element loss may have occurred during a LMO phase, we developed models of Zn isotopic fractionation that are generally applicable to planetary magma oceans. Our objective was to identify conditions that would yield a δ66Zn signature of ∼+1.4‰ within the lunar mantle. For the sake of simplicity, we neglect possible Zn isotopic fractionation during the Giant Impact, and assumed a starting composition equal to the composition of the present-day terrestrial mantle, assuming both the Earth and Moon had zinc 'consanguinity' following their formation. We developed two models: the first simulates evaporative fractionation of Zn only prior to LMO mixing and crystallization; the second simulates continued evaporative fractionation of Zn that persists until ∼75% LMO crystallization. The first model yields a relatively homogenous bulk solid LMO δ66Zn value, while the second results in a stratification of δ66Zn values within the LMO sequence. Loss and/or isolation mechanisms for volatiles are critical to these models; hydrodynamic escape was not a dominant process, but loss of a nascent lunar atmosphere or separation of condensates into a proto-lunar crust are possible mechanisms by which volatiles could be separated from the lunar interior. The results do not preclude models that suggest a lunar volatile depletion episode related to the Giant Impact. Conversely, LMO models for volatile loss do not require loss of volatiles prior to lunar formation. Outgassing during planetary magma ocean phases likely played a profound role in setting the volatile inventories of planets, particularly for low mass bodies that experienced the greatest volatile loss. In turn, our results suggest that the initial compositions of planets that accreted from smaller, highly differentiated planetesimals were likely to be severely volatile depleted.

Redox States of Initial Atmospheres Outgassed on Rocky Planets and Planetesimals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schaefer, Laura; Fegley, Bruce Jr., E-mail: lschaefer@asu.edu

2017-07-10

The Earth and other rocky planets and planetesimals in the solar system formed through the mixing of materials from various radial locations in the solar nebula. This primordial material likely had a range of oxidation states as well as bulk compositions and volatile abundances. We investigate the oxygen fugacity produced by the outgassing of mixtures of solid meteoritic material, which approximate the primitive nebular materials. We find that the gas composition and oxygen fugacity of binary and ternary mixtures of meteoritic materials vary depending on the proportion of reduced versus oxidized material, and also find that mixtures using differentiated materialsmore » do not show the same oxygen fugacity trends as those using similarly reduced but undifferentiated materials. We also find that simply mixing the gases produced by individual meteoritic materials together does not correctly reproduce the gas composition or oxygen fugacity of the binary and ternary mixtures. We provide tabulated fits for the oxygen fugacities of all of the individual materials and binary mixtures that we investigate. These values may be useful in planetary formation models, models of volatile transport on planetesimals or meteorite parent bodies, or models of trace element partitioning during metal-silicate fractionation.« less

Defining the chemical role of H2O in mantle melts: Effect of melt composition and H2O content on the activity of SiO2

NASA Astrophysics Data System (ADS)

Moore, G.; Roggensack, K.

2007-12-01

Quantifying the influence of volatiles (H2O, CO2) on the chemistry of mantle melts is a critical aspect of understanding the petrogenesis of arc magmas. A significant amount of experimental work done on the effect of H2O on the solidii of various mantle compositions, as well as on multiple saturation points of various primitive melts, has shown that H2O stabilizes olivine with respect to orthopyroxene. Or, in other words, at constant activity of SiO2, the presence of H2O decreases the activity coefficient of SiO2 in the melt, potentially leading to mantle melts that have suprisingly high SiO2 contents (Carmichael, 2002). Quantification and modelling of this behavior in hydrous silicate melts in equilibrium with the mantle have proven problematic, due mainly to a relatively small set of experiments that allow this type of thermodynamic analysis, and because of the experimental and analytical difficulties of dealing with hydrous high P-T samples (e.g. quench to a glass, rapid melt-solid reaction on quench, electron beam sensitivity of resulting glass, volatile content determination, etc). A further complication in the existing data includes co-variance of important experimental parameters (e.g. T and H2O content), making robust statistical regression analysis difficult and potentially misleading. We present here results of high P-T experiments conducted at a single pressure and temperature (1.0 GPa, 1200 deg C) that have the specific goal of quantifying the effect of H2O, as well as other melt components, on the activity coefficient of SiO2 in mantle melts. Using a "sandwich" type experiment, basaltic melts are saturated with an olivine plus orthopyroxene mineral assemblage with varying H2O and CO2 contents. The resulting samples have their bulk solid phase and glass compositions determined using EPMA, and the volatile content of the glass is determined by FTIR. The activity of SiO2 is then calculated using the olivine and orthopyroxene compositions. This value is then used, along with the mole fraction of SiO2 that is measured in the glass, to calculate an activity coefficient for SiO2 in that particular melt. The results show that for two starting compositions, H2O clearly has a strong negative effect on the activity coefficient of SiO2, consistent with some earlier intepretations. Further work is being conducted on differing starting compositions, as well as increasing the range of volatile contents, in order to better quantify their influence on this important chemical parameter of mantle melts. Ultimately, these experiments will help determine whether hydrous arc lavas, including high-Mg andesites, can be attributed to a primitive mantle origin, or whether other magmatic processes are necessary to generate their observed bulk compositions. It will also quantify the amount of H2O necessary to generate such magmas, giving insight into the potential H2O content present in the sub-arc mantle source regions, and allowing a more precise estimate of volatile fluxes in volcanic arc settings.

Tomographic location of potential melt-bearing phenocrysts in lunar glass spherules

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ebel, D.S.; Fogel, R.A.; Rivers, M.L.

2005-02-04

Apollo 17 orange glass spherules contain olivine phenocrysts with melt inclusions from depth. Tomography (<2micron/pxl) of >200 spherules located 1 phenocryst. We will try to find melt inclusions and obtain original magma volatiles and compositions. In 1971, Apollo 17 astronauts collected a 10 cm soil sample (74220) comprised almost entirely of orange glass spherules. Below this, a double drive-tube core sampled a 68 cm thick horizon comprised of orange glass and black beads (crystallized equivalents of orange glass). Primitive lunar glass spherules (e.g.-A17 orange glasses) are thought to represent ejecta from lunar mare fire fountains. The fire-fountains were apparently drivenmore » by a combination of C-O gas exsolution from orange glass melt and the oxidation of graphite. Upon eruption, magmas lost their volatiles (e.g., S, CO, CO{sub 2}) to space. Evidence for volatile escape remains as volatile-rich coatings on the exteriors of many spherules. Moreover, it showed that Type I and II Fe-Ni-rich metal particles found within orange glass olivine phenocrysts, or free-floating in the glass itself, are powerful evidence for the volatile driving force for lunar fire fountains. More direct evidence for the volatile mechanism has yet to be uncovered. Issues remaining include: the exact composition of magmatic volatiles; the hypothesized existence of graphite in the magma; the oxygen fugacity of the magma and of the lunar interior. In 1996 reported a single {approx}450 micron, equant olivine phenocryst, containing four glassy melt inclusions (or inclusion cores), the largest {approx}30micron in size, in a thin section of the 74001/2 drill core. The melt is assumed to sample the parent magma of the lunar basalts at depth, evidenced by the S content of the inclusion (600 ppm) which is 400 ppm greater than that of the orange glass host. Such melts potentially contain a full complement of the volatile components of the parent magma, which can be analyzed by infrared spectroscopy. Although the A17 orange glass magma is thought to derive from {approx} 400 km depth, the calculations imply a 4 km depth of graphite oxidation (and melt saturation in C-O volatiles) during ascent. We have imaged several hundred similar orange glass spherules, from sample 74220,764, using synchrotron x-ray computer-aided microtomography (XRCMT). Our goals: (1) locate similar phenocrysts containing melt inclusions; (2) analyze phenocrysts to understand the evolution of the magma; (3) analyze melt and fluid inclusions using EPMA and FTIR to obtain direct evidence of magmatic volatiles and pristine bulk compositions.« less

Worldwide occurrence of silica-rich melts in sub-continental and sub-oceanic mantle minerals

NASA Astrophysics Data System (ADS)

Schiano, P.; Clocchiatti, R.

1994-04-01

ROCK samples derived from the Earth's upper mantle commonly show indirect evidence for chemical modification. Such modification, or 'metasomatism', can be recognized by the precipitation of exotic minerals such as phlogopite, amphibole or apatite1, and by the overprinting of the bulk compositions of the mantle rocks by a chemical signature involving the enrichment of potassium and other 'incompatible' elements2. Here we study the composition of the metasomatic agents more directly by examining melt and fluid inclusions trapped in mantle minerals. These inclusions are secondary, forming trails along healed fracture planes. A systematic study of the chemical compositions and entrapment temperatures and pressures of inclusions from 14 ultramaflc peridotites from both continental and oceanic intraplate regions shows that volatile- and silica-rich metasomatic melts are present throughout the litho-sphere. Their compositions, which differ dramatically from those of erupted, mantle-derived magmas, are more akin to continental than to oceanic crust.

Observational Constraints on Modeling Growth and Evaporation Kinetics of Isoprene SOA

NASA Astrophysics Data System (ADS)

Zaveri, R. A.; Shilling, J. E.; Zelenyuk, A.; Liu, J.; Wilson, J. M.; Laskin, A.; Wang, B.; Fast, J. D.; Easter, R. C.; Wang, J.; Kuang, C.; Thornton, J. A.; Setyan, A.; Zhang, Q.; Onasch, T. B.; Worsnop, D. R.

2014-12-01

Isoprene is thought to be a major contributor to the global secondary organic aerosol (SOA) budget, and therefore has the potential to exert a significant influence on earth's climate via aerosol direct and indirect radiative effects. Both aerosol optical and cloud condensation nuclei properties are quite sensitive to aerosol number size distribution, as opposed to the total aerosol mass concentration. Recent studies suggest that SOA particles can be highly viscous, which can affect the kinetics of SOA partitioning and size distribution evolution when the condensing organic vapors are semi-volatile. In this study, we examine the growth kinetics of SOA formed from isoprene photooxidation in the presence of pre-existing Aitken and accumulation mode aerosols in: (a) the ambient atmosphere during the CARES field campaign, and (b) the environmental chamber at PNNL. Each growth episode is analyzed and interpreted with the updated MOSAIC aerosol box model, which performs kinetic gas-particle partitioning of SOA and takes into account diffusion and chemical reaction within the particle phase. The model is initialized with the observed aerosol size distribution and composition at the beginning of the experiment, and the total amount of SOA formed in the model at any given time is constrained by the observed total amount of SOA formed. The variable model parameters include the number of condensing organic species, their gas-phase formation rates, their effective volatilities, and their bulk diffusivities in the Aitken and accumulation modes. The objective of the constrained modeling exercise is then to determine which model configuration is able to best reproduce the observed size distribution evolution, thus providing valuable insights into the possible mechanism of SOA formation. We also examine the evaporation kinetics of size-selected particles formed in the environmental chamber to provide additional constraints on the effective volatility and bulk diffusivity of the organic species. Our results suggest that SOA formed from isoprene photooxidation is semi-volatile, and the resulting size distribution evolution is highly sensitive to the phase state (bulk diffusivity) of the pre-existing aerosol. Implications of these findings on further SOA model development and evaluation strategy will be discussed.

Co-composting of vegetable wastes and carton: Effect of carton composition and parameter variations.

PubMed

Rawoteea, Soonita Anjeena; Mudhoo, Ackmez; Kumar, Sunil

2017-03-01

The aim of the study was to investigate the effects of carton in the composting process of mixed vegetable wastes using an experimental composter of capacity 80L. Three different mixes were set-up (Mixes 1, 2 and 3) which consisted of vegetable wastes, 2.0kg paper and bulking agents, vegetable wastes, 1.5kg carton and bulking agents, vegetable wastes, 4.5kg carton and bulking agents, respectively. Temperature evolution, pH trends, moisture levels, respiration rates, percentage volatile solids and electrical conductivity were monitored for a period of 50days. The system remained under thermophilic conditions for a very short period due to the small size of the reactor. The three mixes did not exceed a temperature of 55°C, where sanitization takes place by the destruction of pathogens. The highest peak of CO 2 evolution was observed in Mix 2 indicating that maximum microbial degradation took place in that mix. Copyright © 2016. Published by Elsevier Ltd.

From source to surface: Tracking magmatic boron and chlorine input into the geothermal systems of the Taupo Volcanic Zone, New Zealand

NASA Astrophysics Data System (ADS)

Bégué, Florence; Deering, Chad D.; Gravley, Darren M.; Chambefort, Isabelle; Kennedy, Ben M.

2017-10-01

The magmatic contribution into geothermal fluids in the central Taupo Volcanic Zone (TVZ), New Zealand, has been attributed to either andesitic, 'arc-type' fluids, or rhyolitic, 'rift-type' fluids to explain the compositional diversity of discharge waters. However, this model relies on outdated assumptions related to geochemical trends associated with the magma at depth of typical arc to back-arc settings. Current tectonic models have shown that the TVZ is situated within a rifting arc and hosts magmatic systems dominated by distinct rhyolite types, that are likely to have evolved under different conditions than the subordinate andesites. Therefore, a new appraisal of the existing models is required to further understand the origin of the spatial compositional diversity observed in the geothermal fluids and its relationship to the structural setting. Here, we use volatile concentrations (i.e. H2O, Cl, B) from rhyolitic and andesitic mineral-hosted melt inclusions to evaluate the magmatic contribution to the TVZ geothermal systems. The andesite and two different types of rhyolites (R1 and R2) are each distinct in Cl/H2O and B/Cl, which will affect volatile solubility and phase separation (vapor vs. hydrosaline liquid) of the exsolved volatile phase. Ultimately, these key differences in the magmatic volatile constituents will play a significant role in governing the concentration of Cl discharged into geothermal systems. We estimate bulk fluid compositions (B and Cl) in equilibrium with the different melt types to show the potential contribution of 'parent' fluids to the geothermal systems throughout the TVZ. The results of this analysis show that the variability in fluid compositions partly reflects degassing from previously unaccounted for distinct magma source compositions. We suggest the geothermal systems that appear to have an 'arc-type' andesitic fluid contribution are actually derived from a rhyolite melt in equilibrium with a highly crystalline andesite magma. This model is in better agreement with the current understanding of magma petrogenesis in the central TVZ and its atypical rifted-arc tectonic setting, and show that the central TVZ records an arc, not back-arc, fluid signature.

Lunar volatiles: a clue for understanding the evolution of the Moon and a resource to its exploration

NASA Astrophysics Data System (ADS)

Gerasimov, Mikhail

Introduction: The discovery of noticeable hydrogen concentration (believed to be in the form of water) in the polar regions was among the most exciting recent events in the exploration of the Moon. Concentration of water in polar regolith was estimated at a level of 4-6 wt.% [1,2]. Such high concentration of water in polar regolith on volatiles depleted Moon is probably a result of migration of water molecules from its hot equatorial latitudes to cold traps of the northern and southern polar regions. These depositions of volatiles on one hand contain important information on the evolution of the Moon and on the other hand their utilization can be a bases for the future human exploration. The question about diversity and source of the volatiles is still open. Sources of lunar volatiles: Three main possible sources of the Lunar polar volatiles are: Degassing of the interior. Endogenous source of volatiles is provided by degassing of heated interior of planetary bodies. In this case chemical composition of released gases reflects thermodynamic equilibrium of gases over typical magmas at temperatures around 1000°C. The composition of such gas mixtures is characterized by domination of H2O, CO2, and SO2 over other H, C, and S containing components. CO/CO2 ratio here is typically far below 0.1 level. Hydrocarbons are mainly aromatic hydrocarbons, alkanes, and cycloalkanes. Sulfur containing gases are mainly SO2, H2S, and Sx. Isotopic ratios of volatile elements should be the same as for the bulk Moon. Interaction of solar wind protons with surface rocks. Energetic solar wind protons with the absence of an atmospheric shield can react with oxygen of surface rocks and produce water molecules as end product. Such a mechanism provides a source of mainly water on the Moon with solar hydrogen isotopes and Moon rocks oxygen isotopes. Degassing of impacting meteorites and comets. Volatiles of impacting meteorites and comets are released into transient atmosphere. It was shown experimentally [3] that the forming gases are qualitatively similar for various rocky materials including meteorites of different classes. Such gas mixtures have the following characteristics: the CO/CO2 ratio is ³1, hydrocarbons are presented mainly by alkenes and PAHs, sulfur containing gases are presented by SO2, CS2, H2S, and COS in decreasing sequence, production of HCN, and noticeable release of water. Isotopic composition of volatile elements reflects the projectile to target proportion of their source. Gas-analytic package (GAP) of the Lunar-Resource mission: It is very important to investigate all the inventory of polar volatiles as well as isotopic composition of volatile elements to understand the real source of lunar volatiles and to evaluate their validity as a resource for the Moon exploration. The GAP is aimed on comprehensive investigation of the inventory of volatiles in the regolith of polar regions. It consists of three instruments: 1) Thermal Analyzer; 2) Gas Chromatograph with Tunable Diode Laser Absorption Spectrometer for isotopic measurements of H, O, and C in evolved gases; and 3) Neutral Gas Mass-Spectrometer. References: [1] Mitrofanov, I. G. et al. 2010. Science 330: 483-486. [2] Colaprete, A. et al. 2010. Science 330: 463-468. [3] Gerasimov, M.V. 2002. Geological Society of America Special Paper 356: 705-716. Acknowledgements: This work was supported by P-22 Program of the RAS.

Sub-Micrometer Scale Minor Element Mapping in Interplanetary Dust Particles: A Test for Stratospheric Contamination

NASA Technical Reports Server (NTRS)

Flynn, G. J.; Keller, L. P.; Sutton, S. R.

2004-01-01

Combined X-ray microprobe (XRM), energy dispersive x-ray fluorescence using a Transmission Electron Microscope (TEM), and electron microprobe measurements have determined that the average bulk chemical composition of the interplanetary dust particles (IDPs) collected from the Earth s stratosphere is enriched relative to the CI meteorite composition by a factor of 2 to 4 for carbon and for the moderately volatile elements Na, K, P, Mn, Cu, Zn, Ga, Ge, and Se, and enriched to approximately 30 times CI for Br. However, Jessberger et al., who have reported similar bulk enrichments using Proton Induced X-ray Emission (PIXE), attribute the enrichments to contamination by meteor-derived atmospheric aerosols during the several weeks these IDPs reside in the Earth s atmosphere prior to collection. Using scanning Auger spectroscopy, a very sensitive surface analysis technique, Mackinnon and Mogk have observed S contamination on the surface of IDPs, presumably due to the accretion of sulfate aerosols during stratospheric residence. But the S-rich layer they detected was so thin (approximately 100 angstroms thick) that the total amount of S on the surface was too small to significantly perturb the bulk S-content of a chondritic IDP. Stephan et al. provide support for the contamination hypothesis by reporting the enrichment of Br on the edges of the IDPs using Time-of-Flight Secondary-Ion Mass-Spectrometry (TOFSIMS), but TOF-SIMS is notorious for producing false edge-effects, particularly on irregularly-shaped samples like IDPs. Sutton et al. mapped the spatial distribution of Fe, Ni, Zn, Br, and Sr, at the approximately 2 m scale, in four IDPs using element-specific x-ray fluorescence (XRF) computed microtomography. They found the moderately volatile elements Zn and Br, although spatially inhomogeneous, were not concentrated on the surface of any of the IDPs they examined, suggesting that the Zn and the Br enrichments in the IDPs are not due to contamination during stratospheric residence.

Chondritic Mn/Na ratio and limited post-nebular volatile loss of the Earth

NASA Astrophysics Data System (ADS)

Siebert, Julien; Sossi, Paolo A.; Blanchard, Ingrid; Mahan, Brandon; Badro, James; Moynier, Frédéric

2018-03-01

The depletion pattern of volatile elements on Earth and other differentiated terrestrial bodies provides a unique insight as to the nature and origin of planetary building blocks. The processes responsible for the depletion of volatile elements range from the early incomplete condensation in the solar nebula to the late de-volatilization induced by heating and impacting during planetary accretion after the dispersion of the H2-rich nebular gas. Furthermore, as many volatile elements are also siderophile (metal-loving), it is often difficult to deconvolve the effect of volatility from core formation. With the notable exception of the Earth, all the differentiated terrestrial bodies for which we have samples have non-chondritic Mn/Na ratios, taken as a signature of post-nebular volatilization. The bulk silicate Earth (BSE) is unique in that its Mn/Na ratio is chondritic, which points to a nebular origin for the depletion; unless the Mn/Na in the BSE is not that of the bulk Earth (BE), and has been affected by core formation through the partitioning of Mn in Earth's core. Here we quantify the metal-silicate partitioning behavior of Mn at deep magma ocean pressure and temperature conditions directly applicable to core formation. The experiments show that Mn becomes more siderophile with increasing pressure and temperature. Modeling the partitioning of Mn during core formation by combining our results with previous data at lower P-T conditions, we show that the core likely contains a significant fraction (20 to 35%) of Earth's Mn budget. However, we show that the derived Mn/Na value of the bulk Earth still lies on the volatile-depleted end of a trend defined by chondritic meteorites in a Mn/Na vs Mn/Mg plot, which tend to higher Mn/Na with increasing volatile depletion. This suggests that the material that formed the Earth recorded similar chemical fractionation processes for moderately volatile elements as chondrites in the solar nebula, and experienced limited post nebular volatilization.

The origin of inner Solar System water

NASA Astrophysics Data System (ADS)

Alexander, Conel M. O'D.

2017-04-01

Of the potential volatile sources for the terrestrial planets, the CI and CM carbonaceous chondrites are closest to the planets' bulk H and N isotopic compositions. For the Earth, the addition of approximately 2-4 wt% of CI/CM material to a volatile-depleted proto-Earth can explain the abundances of many of the most volatile elements, although some solar-like material is also required. Two dynamical models of terrestrial planet formation predict that the carbonaceous chondrites formed either in the asteroid belt (`classical' model) or in the outer Solar System (5-15 AU in the Grand Tack model). To test these models, at present the H isotopes of water are the most promising indicators of formation location because they should have become increasingly D-rich with distance from the Sun. The estimated initial H isotopic compositions of water accreted by the CI, CM, CR and Tagish Lake carbonaceous chondrites were much more D-poor than measured outer Solar System objects. A similar pattern is seen for N isotopes. The D-poor compositions reflect incomplete re-equilibration with H2 in the inner Solar System, which is also consistent with the O isotopes of chondritic water. On balance, it seems that the carbonaceous chondrites and their water did not form very far out in the disc, almost certainly not beyond the orbit of Saturn when its moons formed (approx. 3-7 AU in the Grand Tack model) and possibly close to where they are found today. This article is part of the themed issue 'The origin, history and role of water in the evolution of the inner Solar System'.

Mars

NASA Astrophysics Data System (ADS)

McSween, H. Y., Jr.; McLennan, S. M.

Of all the planets, Mars is the most Earthlike, inviting geochemical comparisons. Geochemical data for Mars are derived from spacecraft remote sensing, surface measurements and Martian meteorites. These analyses of exposed crustal materials enable estimates of bulk planet composition and inferences about its iron-rich mantle and core, as well as constraints on planetary differentiation and crust-mantle evolution. Mars probably had an early magma ocean, but there is no evidence for plate tectonics or crustal recycling any time in its history. The crust is basaltic in composition and lithologically heterogeneous, with radiometric crystallization ages ranging from ~4 billion years to within the last several hundred million years. Mantle sources for magmas vary considerably in incompatible element abundances. Although Mars is volatile element-rich, estimations of the amount of water delivered to the surface by volcanism are controversial. Low-temperature aqueous alteration affected the ancient Martian surface, producing clay minerals, sulfates, and other secondary minerals. Weathering and diagenetic trends are distinct from terrestrial chemical alteration, indicating different aqueous conditions. Organic matter has been found in Martian meteorites, but no geochemical signal of life has yet been discovered. Dynamic geochemical cycles for some volatile elements are revealed by stable isotope measurements. Long-term secular changes in chemical and mineralogical compositions of igneous rocks and sediments have been documented but are not well understood.

The Prospect of Y2SiO5-Based Materials as Protective Layer in Environmental Barrier Coatings

NASA Astrophysics Data System (ADS)

García, E.; Miranzo, P.; Osendi, M. I.

2013-06-01

Bulk yttrium monosilicate (Y2SiO5) possesses interesting properties, such as low thermal expansion coefficient and stability in water vapor atmospheres, which make it a promising protective layer for SiC-based composites, intended for the hottest parts in the future gas turbines. Because protective layers are commonly applied by thermal spraying techniques, it is important to analyze the changes in structure and properties that these methods may produce in yttrium silicate coatings. In this work, two SiO2-Y2O3 compositions were flame sprayed in the form of coatings and beads. In parallel, the beads were spark plasma sintered at relatively low temperature to obtain partially amorphous bulk specimens that are used as model bulk material. The thermal aging—air and water vapor atmosphere—caused extensive nucleation of Y2SiO5 and Y2Si2O7 in both the bulk and coating. The rich water vapor condition caused the selective volatilization of SiO2 from Y2Si2O7 at the specimen surface leaving a very characteristic micro-ridged Y2SiO5 zones—either in coatings or sintered bodies. An important increase in the thermal conductivity of the aged materials was measured. The results of this work may be used as a reference body for the production of Y2SiO5 coatings using thermal spraying techniques.

Geological Mapping of Pluto and Charon Using New Horizons Data

NASA Astrophysics Data System (ADS)

Moore, J. M.; Spencer, J. R.; McKinnon, W. B.; Howard, A. D.; White, O. M.; Umurhan, O. M.; Schenk, P. M.; Beyer, R. A.; Singer, K.; Stern, S. A.; Weaver, H. A.; Young, L. A.; Ennico Smith, K.; Olkin, C.; Horizons Geology, New; Geophysics Imaging Team

2016-06-01

Pluto and Charon exhibit strikingly different surface appearances, despite their similar densities and presumed bulk compositions. Systematic mapping has revealed that much of Pluto's surface can be attributed to surface-atmosphere interactions and the mobilization of volatile ices by insolation. Many mapped valley systems appear to be the consequence of glaciation involving nitrogen ice. Other geological activity requires or required internal heating. The convection and advection of volatile ices in Sputnik Planum can be powered by present-day radiogenic heat loss. On the other hand, the prominent mountains at the western margin of Sputnik Planum, and the strange, multi-km-high mound features to the south, probably composed of H2O, are young geologically as inferred by light cratering and superposition relationships. Their origin, and what drove their formation so late in Solar System history, is under investigation. The dynamic remolding of landscapes by volatile transport seen on Pluto is not unambiguously evident in the mapping of Charon. Charon does, however, display a large resurfaced plain and globally engirdling extensional tectonic network attesting to its early endogenic vigor.

The Geology of Pluto and Charon as Revealed by New Horizons

NASA Astrophysics Data System (ADS)

Moore, Jeffrey M.; Spencer, John R.; McKinnon, William B.; Stern, S. Alan; Young, Leslie A.; Weaver, Harold A.; Olkin, Cathy B.; Ennico, Kim; New Horizons GGI Team

2016-04-01

NASA's New Horizons spacecraft has revealed that Pluto and Charon exhibit strikingly different surface appearances, despite their similar densities and presumed bulk compositions. Much of Pluto's surface can be attributed to surface-atmosphere interactions and the mobilization of volatile ices by insolation. Many valley systems appear to be the consequence of glaciation involving nitrogen ice. Other geological activity requires or required internal heating. The convection and advection of volatile ices in Sputnik Planum can be powered by present-day radiogenic heat loss. On the other hand, the prominent mountains at the western margin of Sputnik Planum, and the strange, multi-km-high mound features to the south, probably composed of H2O, are young geologically as inferred by light cratering and superposition relationships. Their origin, and what drove their formation so late in Solar System history, is under investigation. The dynamic remolding of landscapes by volatile transport seen on Pluto is not unambiguously evident on Charon. Charon does, however, display a large resurfaced plain and globally engirdling extensional tectonic network attesting to its early endogenic vigor.

The Geology of Pluto and Charon as Revealed by New Horizons

NASA Technical Reports Server (NTRS)

Moore, Jeffrey M.; Spencer, John R.; McKinnon, William B.; Stern, S. Alan; Young, Leslie A.; Weaver, Harold A.; Olkin, Cathy B.; Ennico, Kim

2016-01-01

NASA's New Horizons spacecraft has revealed that Pluto and Charon exhibit strikingly different surface appearances, despite their similar densities and presumed bulk compositions. Much of Pluto's surface can be attributed to surface-atmosphere interactions and the mobilization of volatile ices by insolation. Many valley systems appear to be the consequence of glaciation involving nitrogen ice. Other geological activity requires or required internal heating. The convection and advection of volatile ices in Sputnik Planum can be powered by present-day radiogenic heat loss. On the other hand, the prominent mountains at the western margin of Sputnik Planum, and the strange, multi-km-high mound features to the south, probably composed of H2O, are young geologically as inferred by light cratering and superposition relationships. Their origin, and what drove their formation so late in Solar System history, is under investigation. The dynamic remolding of landscapes by volatile transport seen on Pluto is not unambiguously evident on Charon. Charon does, however, display a large resurfaced plain and globally engirdling extensional tectonic network attesting to its early endogenic vigor.

El Chichon - Composition of plume gases and particles

NASA Technical Reports Server (NTRS)

Kotra, J. P.; Finnegan, D. L.; Zoller, W. H.; Hart, M. A.; Moyers, J. L.

1983-01-01

Aircraft measurements were made of trace gases, atmospheric particles, and condensed acid volatiles in the plume of El Chichon volcano, Chiapas, Mexico, in November 1982. Hydrogen sulfide was the primary gaseous sulfur species in the plume at the time of collection. Concentrations of 28 elements were determined by neutron activation analysis of particulate material from the plume. The volatile elements sulfur, chlorine, arsenic, selenium, bromine, antimony, iodine, tungsten, and mercury were enriched relative to bulk pyroclastic material by factors of 60 to 20,000. Arsenic, antimony, and selenium were associated predominantly with small (not greater than 3 micrometer) particles. Calcium and sodium were present almost exclusively on larger particles and aluminum and manganese were bimodally distributed. Ashladen particulate material injected into the stratosphere during the early violent eruptions was enriched by factors of 10 to 30 relative to ash in some of the same elements observed in the quiescent plume.

Partitioning of U, Th and K Between Metal, Sulfide and Silicate, Insights into the Volatile-Content of Mercury

NASA Technical Reports Server (NTRS)

Habermann, M.; Boujibar, A.; Righter, K.; Danielson, L.; Rapp, J.; Righter, M.; Pando, K.; Ross, D. K.; Andreasen, R.; Chidester, B.

2016-01-01

During the early stages of the Solar System formation, especially during the T-Tauri phase, the Sun emitted strong solar winds, which are thought to have expelled a portion of the volatile elements from the inner solar system. It is therefore usually believed that the volatile depletion of a planet is correlated with its proximity to the Sun. This trend was supported by the K/Th and K/U ratios of Venus, the Earth, and Mars. Prior to the MESSENGER mission, it was expected that Mercury is the most volatile-depleted planet. However, the Gamma Ray Spectrometer of MESSENGER spacecraft revealed elevated K/U and K/Th ratios for the surface of Mercury, much higher than previous expectations. It is possible that the K/Th and K/U ratios on the surface are not a reliable gauge of the bulk volatile content of Mercury. Mercury is enriched in sulfur and is the most reduced of the terrestrial planets, with oxygen fugacity (fO2) between IW-6.3 and IW-2.6 log units. At these particular compositions, U, Th and K behave differently and can become more siderophile or chalcophile. If significant amounts of U and Th are sequestered in the core, the apparent K/U and K/Th ratios measured on the surface may not represent the volatile budget of the whole planet. An accurate determination of the partitioning of these elements between silicate, metal, and sulfide phases under Mercurian conditions is therefore essential to better constrain Mercury's volatile content and assess planetary formation models.

Reactive processing and mechanical properties of polymer derived silicon nitride matrix composites and their use in coating and joining ceramics and ceramic matrix composites

NASA Astrophysics Data System (ADS)

Stackpoole, Margaret Mary

Use of preceramic polymers offers many advantages over conventional ceramic processing routes. Advantages include being able to plastically form the part, form a pyrolized ceramic material at lower temperatures and form high purity microstructures which are tailorable depending on property requirements. To date preceramic polymers are mostly utilized in the production of low dimensional products such as fibers since loss of volatiles during pyrolysis leads to porosity and large shrinkage (in excess of 30%). These problems have been partially solved by use of active fillers (e.g. Ti, Cr, B). The reactive filler converts to a ceramic material with a volume expansion and this increases the density and reduces shrinkage and porosity. The expansion of the reactive filler thus compensates for the polymer shrinkage if the appropriate volume fraction of filler is present in a reactive atmosphere (e.g. N2 or NH3). This approach has resulted in structural composites with limited success. The present research investigates the possibility of using filled preceramic polymers to form net shaped ceramic composite materials and to investigate the use of these unique composite materials to join and coat ceramics and ceramic composites. The initial research focused on phase and microstructural development of bulk composites from the filled polymer/ceramic systems. A processing technique was developed to insure consistency between different samples and the most promising filler/polymer choices for this application have been determined. The processing temperatures and atmospheres have also been optimized. The work covers processing and characterization of bulk composites, joints and coatings. With careful control of processing near net shape bulk composites were fabricated. Both ambient and high temperature strength and fracture toughness was obtained for these composite systems. The potential of using reactively filled preceramic polymers to process joints and coatings was also investigated. A critical thickness below which crack free joints/coatings could be processed was determined. Finally, mechanical properties of the joints and coatings at ambient and elevated temperatures (including oxidation studies) have been evaluated. The interfacial fracture behavior of the joints and coatings was also evaluated.

A volatile topic: Parsing out the details of Earth's formation through experimental metal-silicate partitioning of volatile and moderately volatile elements

NASA Astrophysics Data System (ADS)

Mahan, B. M.; Siebert, J.; Blanchard, I.; Badro, J.; Sossi, P.; Moynier, F.

2017-12-01

Volatile and moderately volatile elements display different volatilities and siderophilities, as well as varying sensitivity to thermodynamic controls (X, P, T, fO2) during metal-silicate differentiation. The experimental determination of the metal-silicate partitioning of these elements permits us to evaluate processes controlling the distribution of these elements in Earth. In this work, we have combined metal-silicate partitioning data and results for S, Sn, Zn and Cu, and input these characterizations into Earth formation models. Model parameters such as source material, timing of volatile delivery, fO2 path, and degree of impactor equilibration were varied to encompass an array of possible formation scenarios. These models were then assessed to discern plausible sets of conditions that can produce current observed element-to-element ratios (e.g. S/Zn) in the Earth's present-day mantle, while also satisfying current estimates on the S content of the core, at no more than 2 wt%. The results of our models indicate two modes of accretion that can maintain chondritic element-to-element ratios for the bulk Earth and can arrive at present-day mantle abundances of these elements. The first mode requires the late addition of Earth's entire inventory of these elements (assuming a CI-chondritic composition) and late-stage accretion that is marked by partial equilibration of large impactors. The second, possibly more intuitive mode, requires that Earth accreted - at least initially - from volatile poor material preferentially depleted in S relative to Sn, Zn, and Cu. From a chemical standpoint, this source material is most similar to type I chondrule rich (and S poor) materials (Hewins and Herzberg, 1996; Mahan et al., 2017; Amsellem et al., 2017), such as the metal-bearing carbonaceous chondrites.

The Plumbing System of a Highly Explosive Basaltic Volcano: Sunset Crater, AZ

NASA Astrophysics Data System (ADS)

Allison, C. M.; Roggensack, K.; Clarke, A. B.

2015-12-01

We seek to better understand highly explosive basaltic eruptions with specific focus on magmatic volatile solubility in alkali basalts and the magma plumbing system. Sunset Crater, an alkali basalt (~3.7 wt.% alkalis) scoria cone volcano, erupted explosively in 1085 AD. We analyzed 125 primary melt inclusions (MIs) from Sunset Crater tephra deposited by 2 subplinian phases and 1 Strombolian explosion to compare magma volatiles and storage conditions. We picked rapidly quenched free olivine crystals and selected large volume MIs (50-180 μm) located toward crystal cores. MIs are faceted and exhibit little major element composition variability with minor post entrapment crystallization (2-10%). MIs are relatively dry but CO2-rich. Water content varies from 0.4 wt.% to 1.5 wt.% while carbon dioxide abundance ranges between 1,150 ppm and 3,250 ppm. Most MIs contain >1 wt.% H2O and >2,150 ppm CO2. All observed MIs contain a vapor bubble, so we are evaluating MI vapor bubbles with Raman spectroscopy and re-homogenization experiments to determine the full volatile budget. Because knowledge of volatile solubility is critical to accurately interpret results from MI analyses, we measured H2O-CO2 solubility in the Sunset Crater bulk composition. Fluid-saturated experiments at 4 and 6 kbar indicate shallower entrapment pressures for these MIs than values calculated for this composition using existing models. Assuming fluid saturation, MIs record depths from 6 km to 14 km, including groupings suggesting two pauses for longer-term storage at ~6 km and ~10.5 km. We do not observe any significant differences in MIs from phases exhibiting different eruptive styles, suggesting that while a high CO2 content may drive rapid magma ascent and be partly responsible for highly explosive eruptions, shallower processes may govern the final eruptive character. To track shallow processes during magma ascent from depth of MI-entrapment up to the surface, we are examining MI re-entrants.

Ca-,Al-rich inclusions in the unique chondrite ALH85085 - Petrology, chemistry, and isotopic compositions

NASA Technical Reports Server (NTRS)

Kimura, Makoto; El-Goresy, Ahmed; Palme, Herbert; Zinner, Ernst

1993-01-01

A comprehensive study is performed for the Ca-,Al-rich inclusions (CAIs) in the unique chondrite ALH85085. The ALH85085 inclusions are smaller (5-80 microns) and more refractory than their counterparts in carbonaceous chondrites. The study includes 42 inclusions for petrography and mineralogy, 15 for bulk major and minor element chemical composition, six for Mg-Al isotopic systematics, 10 for Ca isotopes, nine for Ti isotopes, and six for trace element abundances. In addition, oxygen-isotopic compositions were determined in minerals from a single inclusion. No correlation is found between mineralogy, major element chemistry, and trace element abundances. It is further shown that the high-temperature geochemical behavior of ultrarefractory trace elements is decoupled from that of the major elements Ca and Ti (Ti is correlated with the relatively volatile elements Nb and Yb) implying that perovskite is of only minor importance as carrier of ultrarefractories.

The mini-CIDEX GC/IMS: Analysis of cometary ice and dust

NASA Technical Reports Server (NTRS)

Kojiro, Daniel R.; Carle, Glenn C.; Humphry, Donald E.; Shao, Maxine; Takeuchi, Nori

1995-01-01

Comets are recognized as among the most scientifically important objects in the solar system. They are presumed relics of the early primitive material in the solar nebula and are believed to have provided a general enrichment of volatiles to the inner solar system. The Cometary Coma Chemical Composition (C4) Mission, a proposed Discovery-Class Mission, will analyze materials released into the coma, providing information leading to the understanding of the chemical composition and make-up of the cometary nucleus. As one of two scientific instruments in the C4 spacecraft, an advanced and streamlined version of the Cometary Ice and Dust Experiment (CIDEX), a mini-CIDEX, will employ an X-Ray Fluorescence (XRF) spectrometer to determine bulk elemental composition of cometary dust grains and a Gas Chromatograph/Ion Mobility Spectrometer (GC/IMS) for determination of the molecular composition of dust and ices following stepwise pyrolysis and combustion. A description of the mini-CIDEX IMS will be provided as well as data from analyses conducted using the mini-CIDEX breadboard instrument.

The origin of inner Solar System water.

PubMed

Alexander, Conel M O'D

2017-05-28

Of the potential volatile sources for the terrestrial planets, the CI and CM carbonaceous chondrites are closest to the planets' bulk H and N isotopic compositions. For the Earth, the addition of approximately 2-4 wt% of CI/CM material to a volatile-depleted proto-Earth can explain the abundances of many of the most volatile elements, although some solar-like material is also required. Two dynamical models of terrestrial planet formation predict that the carbonaceous chondrites formed either in the asteroid belt ('classical' model) or in the outer Solar System (5-15 AU in the Grand Tack model). To test these models, at present the H isotopes of water are the most promising indicators of formation location because they should have become increasingly D-rich with distance from the Sun. The estimated initial H isotopic compositions of water accreted by the CI, CM, CR and Tagish Lake carbonaceous chondrites were much more D-poor than measured outer Solar System objects. A similar pattern is seen for N isotopes. The D-poor compositions reflect incomplete re-equilibration with H 2 in the inner Solar System, which is also consistent with the O isotopes of chondritic water. On balance, it seems that the carbonaceous chondrites and their water did not form very far out in the disc, almost certainly not beyond the orbit of Saturn when its moons formed (approx. 3-7 AU in the Grand Tack model) and possibly close to where they are found today.This article is part of the themed issue 'The origin, history and role of water in the evolution of the inner Solar System'. © 2017 The Author(s).

Tight coupling of particle size and composition in atmospheric cloud droplet activation

NASA Astrophysics Data System (ADS)

Topping, D.; McFiggans, G.

2011-09-01

The substantial uncertainty in the indirect effect on radiative forcing in large part arises from the influences of atmospheric aerosol particles on (i) the brightness of clouds, exerting significant shortwave cooling with no appreciable compensation in the longwave, and on (ii) their ability to precipitate, with implications for cloud cover and lifetime. Predicting the ambient conditions at which aerosol particles may become cloud droplets is largely reliant on an equilibrium relationship derived in 1936. However, the theoretical basis of the relationship restricts its application to particles solely comprising involatile compounds and water, whereas a substantial fraction of particles in the real atmosphere will contain potentially thousands of semi-volatile organic compounds in addition to containing semi-volatile inorganic components such as ammonium nitrate. We show that equilibration of atmospherically reasonable concentrations of organic compounds with a growing particle as the ambient humidity increases has larger implications on cloud droplet formation than any other equilibrium compositional dependence, owing to inextricable linkage between the aerosol composition and a particles size under ambient conditions. Whilst previous attempts to account for co-condensation of gases other than water vapour have been restricted to one inorganic condensate, our method demonstrates that accounting for the co-condensation of any number of organic compounds substantially decreases the saturation ratio of water vapour required for droplet activation. This effect is far greater than any other compositional dependence; moreso even than the unphysical effect of surface tension reduction in aqueous organic mixtures, ignoring differences in bulk and surface surfactant concentrations.

Search for Nucleosynthetic Cadmium Isotope Variations in Bulk Carbonaceous Chondrites

NASA Astrophysics Data System (ADS)

Toth, E. R.; Schönbächler, M.; Friebel, M.; Fehr, M. A.

2016-08-01

New high-precision Cd isotope data will be presented for bulk carbonaceous chondrites, such as Allende and Murchison. Volatile element isotope anomalies and their potential nucleosynthetic sources will be discussed.

Inward migration of the TRAPPIST-1 planets as inferred from their water-rich compositions

NASA Astrophysics Data System (ADS)

Unterborn, Cayman T.; Desch, Steven J.; Hinkel, Natalie R.; Lorenzo, Alejandro

2018-04-01

Multiple planet systems provide an ideal laboratory for probing exoplanet composition, formation history and potential habitability. For the TRAPPIST-1 planets, the planetary radii are well established from transits1,2, with reasonable mass estimates coming from transit timing variations2,3 and dynamical modelling4. The low bulk densities of the TRAPPIST-1 planets demand substantial volatile content. Here we show, using mass-radius-composition models, that TRAPPIST-1f and g probably contain substantial (≥50 wt%) water/ice, with TRAPPIST-1 b and c being significantly drier (≤15 wt%). We propose that this gradient of water mass fractions implies that planets f and g formed outside the primordial snow line whereas b and c formed within it. We find that, compared with planets in our Solar System that also formed within the snow line, TRAPPIST-1b and c contain hundreds more oceans of water. We demonstrate that the extent and timescale of migration in the TRAPPIST-1 system depends on how rapidly the planets formed and the relative location of the primordial snow line. This work provides a framework for understanding the differences between the protoplanetary disks of our Solar System versus M dwarfs. Our results provide key insights into the volatile budgets, timescales of planet formation and migration history of M dwarf systems, probably the most common type of planetary host in the Galaxy.

Compositional Imprints in Density–Distance–Time: A Rocky Composition for Close-in Low-mass Exoplanets from the Location of the Valley of Evaporation

NASA Astrophysics Data System (ADS)

Jin, Sheng; Mordasini, Christoph

2018-02-01

We use an end-to-end model of planet formation, thermodynamic evolution, and atmospheric escape to investigate how the statistical imprints of evaporation depend on the bulk composition of planetary cores (rocky versus icy). We find that the population-wide imprints like the location of the “evaporation valley” in the distance–radius plane and the corresponding bimodal radius distribution clearly differ depending on the bulk composition of the cores. Comparison with the observed position of the valley suggests that close-in low-mass Kepler planets have a predominantly Earth-like rocky composition. Combined with the excess of period ratios outside of MMR, this suggests that low-mass Kepler planets formed inside of the water iceline but were still undergoing orbital migration. The core radius becomes visible for planets losing all primordial H/He. For planets in this “triangle of evaporation” in the distance–radius plane, the degeneracy in composition is reduced. In the observed planetary mass–mean density diagram, we identify a trend to more volatile-rich compositions with an increasing radius (R/R ⊕ ≲ 1.6 rocky; 1.6–3.0 ices, and/or H/He ≳3: H/He). The mass–density diagram contains important information about formation and evolution. Its characteristic broken V-shape reveals the transitions from solid planets to low-mass core-dominated planets with H/He and finally to gas-dominated giants. Evaporation causes the density and orbital distance to be anticorrelated for low-mass planets in contrast to giants, where closer-in planets are less dense, likely due to inflation. The temporal evolution of the statistical properties reported here will be of interest for the PLATO 2.0 mission, which will observe the temporal dimension.

Formation of Apollo 16 impactites and the composition of late accreted material: Constraints from Os isotopes, highly siderophile elements and sulfur abundances

NASA Astrophysics Data System (ADS)

Gleißner, Philipp; Becker, Harry

2017-03-01

Fe-Ni metal-schreibersite-troilite intergrowths in Apollo 16 impact melt rocks and new highly siderophile element (HSE) and S abundance data indicate that millimeter-scale closed-system fractional crystallization processes during cooling of impactor-derived metal melt droplets in impact-melts are the main reason for compositional variations and strong differences in abundances and ratios of HSE in multiple aliquots from Apollo 16 impact melt rocks. Element ratios obtained from linear regression of such data are therefore prone to error, but weighted averages take into account full element budgets in the samples and thus represent a more accurate estimate of their impactor contributions. Modeling of solid metal-liquid metal partitioning in the Fe-Ni-S-P system and HSE patterns in impactites from different landing sites suggest that bulk compositions of ancient lunar impactites should be representative of impact melt compositions and that large-scale fractionation of the HSE by in situ segregation of solid metal or sulfide liquid in impact melt sheets most likely did not occur. The compositional record of lunar impactites indicates accretion of variable amounts of chondritic and non-chondritic impactor material and the mixing of these components during remelting of earlier ejecta deposits. The non-chondritic composition appears most prominently in some Apollo 16 impactites and is characterized by suprachondritic HSE/Ir ratios which increase from refractory to moderately volatile HSE and exhibit a characteristic enrichment of Ru relative to Pt. Large-scale fractional crystallization of solid metal from sulfur and phosphorous rich metallic melt with high P/S in planetesimal or embryo cores is currently the most likely process that may have produced these compositions. Similar materials or processes may have contributed to the HSE signature of the bulk silicate Earth (BSE).

Efficient mixing of the solar nebula from uniform Mo isotopic composition of meteorites.

PubMed

Becker, Harry; Walker, Richard J

2003-09-11

The abundances of elements and their isotopes in our Galaxy show wide variations, reflecting different nucleosynthetic processes in stars and the effects of Galactic evolution. These variations contrast with the uniformity of stable isotope abundances for many elements in the Solar System, which implies that processes efficiently homogenized dust and gas from different stellar sources within the young solar nebula. However, isotopic heterogeneity has been recognized on the subcentimetre scale in primitive meteorites, indicating that these preserve a compositional memory of their stellar sources. Small differences in the abundance of stable molybdenum isotopes in bulk rocks of some primitive and differentiated meteorites, relative to terrestrial Mo, suggest large-scale Mo isotopic heterogeneity between some inner Solar System bodies, which implies physical conditions that did not permit efficient mixing of gas and dust. Here we report Mo isotopic data for bulk samples of primitive and differentiated meteorites that show no resolvable deviations from terrestrial Mo. This suggests efficient mixing of gas and dust in the solar nebula at least to 3 au from the Sun, possibly induced by magnetohydrodynamic instabilities. These mixing processes must have occurred before isotopic fractionation of gas-phase elements and volatility-controlled chemical fractionations were established.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jura, M.; Xu, S.; Klein, B.

Using ultraviolet spectra obtained with the Cosmic Origins Spectrograph on the Hubble Space Telescope, we extend our previous ground-based optical determinations of the composition of the extrasolar asteroids accreted onto two white dwarfs, GD 40 and G241-6. Combining optical and ultraviolet spectra of these stars with He-dominated atmospheres, 13 and 12 polluting elements are confidently detected in GD 40 and G241-6, respectively. For the material accreted onto GD 40, the volatile elements C and S are deficient by more than a factor of 10 and N by at least a factor of 5 compared to their mass fractions in primitivemore » CI chondrites and approach what is inferred for bulk Earth. A similar pattern is found for G241-6 except that S is undepleted. We have also newly detected or placed meaningful upper limits for the amount of Cl, Al, P, Ni, and Cu in the accreted matter. Extending results from optical studies, the mass fractions of refractory elements in the accreted parent bodies are similar to what is measured for bulk Earth and chondrites. Thermal processing, perhaps interior to a snow line, appears to be of central importance in determining the elemental compositions of these particular extrasolar asteroids.« less

Phase Equilibrium Experiments on Potential Lunar Core Compositions: Extension of Current Knowledge to Multi-Component (Fe-Ni-Si-S-C) Systems

NASA Technical Reports Server (NTRS)

Righter, K.; Pando, K.; Danielson, L.

2014-01-01

Numerous geophysical and geochemical studies have suggested the existence of a small metallic lunar core, but the composition of that core is not known. Knowledge of the composition can have a large impact on the thermal evolution of the core, its possible early dynamo creation, and its overall size and fraction of solid and liquid. Thermal models predict that the current temperature at the core-mantle boundary of the Moon is near 1650 K. Re-evaluation of Apollo seismic data has highlighted the need for new data in a broader range of bulk core compositions in the PT range of the lunar core. Geochemical measurements have suggested a more volatile-rich Moon than previously thought. And GRAIL mission data may allow much better constraints on the physical nature of the lunar core. All of these factors have led us to determine new phase equilibria experimental studies in the Fe-Ni-S-C-Si system in the relevant PT range of the lunar core that will help constrain the composition of Moon's core.

Elemental depletions in Antarctic micrometeorites and Arctic cosmic spherules: Comparison and relationships

NASA Technical Reports Server (NTRS)

Presper, T.; Kurat, G.; Koeberl, C.; Palme, H.; Maurette, Michel

1993-01-01

Antarctic micrometeorites (MM's) and Arctic cosmic spherules (CS's) have bulk compositions comparable to those of chondritic meteorites. However, abundance of Na, Ca, Mn, Ni, Co, and S are commonly lower in MM's and CS's as compared to chondrites. Our SEM, EMP, and INAA studies suggest that these elemental depletions in unmelted MM's are likely to be due to leaching of soluble components from the MM's in the upper atmosphere and the melt ice water. Depletions in CS's appear to be mainly due to volatilization during melting in the atmosphere or to sampling bias during aggregate formation or parent rock break-up.

The properties and behavior of α-pinene secondary organic aerosol particles exposed to ammonia under dry conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bell, David M.; Imre, Dan; T. Martin, Scot

Chemical transformations and aging of secondary organic aerosol (SOA) particles can alter their physical and chemical properties, including particle morphology. Ammonia, one of the common atmospheric reactive constituents, can react with SOA particles, changing their properties and behavior. At low relative humidity NH3 uptake by α-pinene SOA particles appears to be limited to the particle surface, which suggests that the reacted particles might not be homogeneous and have complex morphology. Here, we present a study aimed at detailed characterization of the effect of ammonia on the composition, density, morphology, shape, and evaporation kinetics of α-pinene SOA particles. We find thatmore » a small amount of NH3 diffuses and reacts throughout the particles bulk, while most of the ammoniated products result from the reaction of NH3 with carboxylic acids on the particle surface, leading to a slight increase in particle size. We show that the reaction products form a solid semi-volatile coating that is a few nanometers thick. This solid coating prevents coagulating particles from coalescing for over two days. However, when the gas phase is diluted this semi-volatile coating evaporates in minutes, which is ensued by rapid coalescence. The ammoniated products in the particle bulk affect particles evaporation kinetics, more so for the smaller particles that contain higher fraction of ammoniated products.« less

Bulk Viscosity of Bubbly Magmas and the Amplification of Pressure Waves

NASA Astrophysics Data System (ADS)

Navon, O.; Lensky, N. G.; Neuberg, J. W.; Lyakhovsky, V.

2001-12-01

The bulk viscosity of magma is needed in order to describe the dynamics of a compressible bubbly magma flowing in conduits and to follow the attenuation of pressure waves travelling through a compressible magma. We developed a model for the bulk viscosity of a suspension of gas bubbles in an incompressible Newtonian liquid that exsolves volatiles (e.g. magma). The suspension is modeled as a close pack of spherical cells, consisting of gas bubbles centered in spherical shells of a volatile-bearing liquid. Following a drop in the ambient pressure the resulting dilatational motion and driving pressure are obtained in terms of the two-phase cell parameters, i.e. bubble radius and gas pressure. By definition, the bulk viscosity of a fluid is the relation between changes of the driving pressure with respect to changes in the resulted expansion strain-rate. Thus, we can use the two-phase solution to define the bulk viscosity of a hypothetical cell, composed of a homogeneously compressible, one-phase, continuous fluid. The resulted bulk viscosity is highly non-linear. At the beginning of the expansion process, when gas exsolution is efficient, the expansion rate grows exponentially while the driving pressure decreases slightly. That means that bulk viscosity is formally negative. The negative value reflects the release of the energy stored in the supersaturated liquid (melt) and its conversion to mechanical work during exsolution. Later, when bubbles are large enough and the gas influx decreases significantly, the strain rate decelerates and the bulk viscosity becomes positive as expected in a dissipative system. We demonstrate that amplification of seismic wave travelling through a volcanic conduit filled with a volatile saturated magma may be attributed to the negative bulk viscosity of the compressible magma. Amplification of an expansion wave may, at some level in the conduit, damage the conduit walls and initiate opening of new pathways for magma to erupt.

Imaging of the CO snow line in a solar nebula analog.

PubMed

Qi, Chunhua; Öberg, Karin I; Wilner, David J; D'Alessio, Paola; Bergin, Edwin; Andrews, Sean M; Blake, Geoffrey A; Hogerheijde, Michiel R; van Dishoeck, Ewine F

2013-08-09

Planets form in the disks around young stars. Their formation efficiency and composition are intimately linked to the protoplanetary disk locations of "snow lines" of abundant volatiles. We present chemical imaging of the carbon monoxide (CO) snow line in the disk around TW Hya, an analog of the solar nebula, using high spatial and spectral resolution Atacama Large Millimeter/Submillimeter Array observations of diazenylium (N2H(+)), a reactive ion present in large abundance only where CO is frozen out. The N2H(+) emission is distributed in a large ring, with an inner radius that matches CO snow line model predictions. The extracted CO snow line radius of ~30 astronomical units helps to assess models of the formation dynamics of the solar system, when combined with measurements of the bulk composition of planets and comets.

Noble gases recycled into the mantle through cold subduction zones

NASA Astrophysics Data System (ADS)

Smye, Andrew J.; Jackson, Colin R. M.; Konrad-Schmolke, Matthias; Hesse, Marc A.; Parman, Steve W.; Shuster, David L.; Ballentine, Chris J.

2017-08-01

Subduction of hydrous and carbonated oceanic lithosphere replenishes the mantle volatile inventory. Substantial uncertainties exist on the magnitudes of the recycled volatile fluxes and it is unclear whether Earth surface reservoirs are undergoing net-loss or net-gain of H2O and CO2. Here, we use noble gases as tracers for deep volatile cycling. Specifically, we construct and apply a kinetic model to estimate the effect of subduction zone metamorphism on the elemental composition of noble gases in amphibole - a common constituent of altered oceanic crust. We show that progressive dehydration of the slab leads to the extraction of noble gases, linking noble gas recycling to H2O. Noble gases are strongly fractionated within hot subduction zones, whereas minimal fractionation occurs along colder subduction geotherms. In the context of our modelling, this implies that the mantle heavy noble gas inventory is dominated by the injection of noble gases through cold subduction zones. For cold subduction zones, we estimate a present-day bulk recycling efficiency, past the depth of amphibole breakdown, of 5-35% and 60-80% for 36Ar and H2O bound within oceanic crust, respectively. Given that hotter subduction dominates over geologic history, this result highlights the importance of cooler subduction zones in regassing the mantle and in affecting the modern volatile budget of Earth's interior.

Gas phase acid, ammonia and aerosol ionic and trace element concentrations at Cape Verde during the Reactive Halogens in the Marine Boundary Layer (RHaMBLe) 2007 intensive sampling period

NASA Astrophysics Data System (ADS)

Sander, R.; Pszenny, A. A. P.; Keene, W. C.; Crete, E.; Deegan, B.; Long, M. S.; Maben, J. R.; Young, A. H.

2013-07-01

We report mixing ratios of soluble reactive trace gases sampled with mist chambers and the chemical composition of bulk aerosol and volatile inorganic bromine (Brg) sampled with filter packs during the Reactive Halogens in the Marine Boundary Layer (RHaMBLe) field campaign at the Cape Verde Atmospheric Observatory (CVAO) on São Vicente island in the tropical North Atlantic in May and June 2007. The gas-phase data include HCl, HNO3, HONO, HCOOH, CH3COOH, NH3, and volatile reactive chlorine other than HCl (Cl*). Aerosol samples were analyzed by neutron activation (Na, Al, Cl, V, Mn, and Br) and ion chromatography (SO42-, Cl-, Br-, NH4+, Na+, K+, Mg2+, and Ca2+). Content and quality of the data, which are available under doi:10.5281/zenodo.6956, are presented and discussed.

Gas phase acid, ammonia and aerosol ionic and trace element concentrations at Cape Verde during the Reactive Halogens in the Marine Boundary Layer (RHaMBLe) 2007 intensive sampling period

NASA Astrophysics Data System (ADS)

Sander, R.; Pszenny, A. A. P.; Keene, W. C.; Crete, E.; Deegan, B.; Long, M. S.; Maben, J. R.; Young, A. H.

2013-12-01

We report mixing ratios of soluble reactive trace gases sampled with mist chambers and the chemical composition of bulk aerosol and volatile inorganic bromine (Brg) sampled with filter packs during the Reactive Halogens in the Marine Boundary Layer (RHaMBLe) field campaign at the Cape Verde Atmospheric Observatory (CVAO) on São Vicente island in the tropical North Atlantic in May and June 2007. The gas-phase data include HCl, HNO3, HONO, HCOOH, CH3COOH, NH3, and volatile reactive chlorine other than HCl (Cl*). Aerosol samples were analyzed by neutron activation (Na, Al, Cl, V, Mn, and Br) and ion chromatography (SO42-, Cl-, Br-, NH4+, Na+, K+, Mg2+, and Ca2+). Content and quality of the data, which are available under doi:10.5281/zenodo.6956, are presented and discussed.

Fractionation of highly siderophile and chalcogen elements in components of EH3 chondrites

NASA Astrophysics Data System (ADS)

Kadlag, Yogita; Becker, Harry

2015-07-01

Abundances of highly siderophile elements (HSE: Re, platinum group elements and Au), chalcogens (Te, Se and S), 187Os/188Os and the major and minor elements Mg, Ca, Mn, Fe, Ni and Co were determined in the components of Sahara 97072 (EH3, find) and Kota Kota (EH3, find) in order to understand the element fractionation processes. In a 187Re-187Os isochron diagram, most magnetic components lie close to the 4.56 Ga IIIA iron meteorite isochron, whereas most other components show deviations from the isochron caused by late redistribution of Re, presumably during terrestrial weathering. Metal- and sulfide rich magnetic fractions and metal-sulfide nodules are responsible for the higher 187Os/188Os in bulk rocks of EH chondrites compared to CI chondrites. The HSE and chalcogens are enriched in magnetic fractions relative to slightly magnetic and nonmagnetic fractions and bulk compositions, indicating that Fe-Ni metal is the main host phase of the HSE in enstatite chondrites. HSE abundance patterns indicate mixing of two components, a CI chondrite like end member and an Au-enriched end member. Because of the decoupled variations of Au from those of Pd or the chalcogens, the enrichment of Au in EH metal cannot be due to metal-sulfide-silicate partitioning processes. Metal and sulfide rich nodules may have formed by melting and reaction of pre-existing refractory element rich material with volatile rich gas. A complex condensation and evaporation history is required to account for the depletion of elements having very different volatility than Au in EH chondrites. The depletions of Te relative to HSE, Se and S in bulk EH chondrites are mainly caused by the depletion of Te in metal. S/Se and S/Mn are lower than in CI chondrites in almost all components and predominantly reflect volatility-controlled loss of sulfur. The latter most likely occurred during thermal processing of dust in the solar nebula (e.g., during chondrule formation), followed by the non-systematic loss of S during terrestrial weathering.

Heterogeneously entrapped, vapor-rich melt inclusions record pre-eruptive magmatic volatile contents

NASA Astrophysics Data System (ADS)

Steele-MacInnis, Matthew; Esposito, Rosario; Moore, Lowell R.; Hartley, Margaret E.

2017-04-01

Silicate melt inclusions (MI) commonly provide the best record of pre-eruptive H2O and CO2 contents of subvolcanic melts, but the concentrations of CO2 and H2O in the melt (glass) phase within MI can be modified by partitioning into a vapor bubble after trapping. Melt inclusions may also enclose vapor bubbles together with the melt (i.e., heterogeneous entrapment), affecting the bulk volatile composition of the MI, and its post-entrapment evolution. In this study, we use numerical modeling to examine the systematics of post-entrapment volatile evolution within MI containing various proportions of trapped vapor from zero to 95 volume percent. Modeling indicates that inclusions that trap only a vapor-saturated melt exhibit significant decrease in CO2 and moderate increase in H2O concentrations in the melt upon nucleation and growth of a vapor bubble. In contrast, inclusions that trap melt plus vapor exhibit subdued CO2 depletion at equivalent conditions. In the extreme case of inclusions that trap mostly the vapor phase (i.e., CO2-H2O fluid inclusions containing trapped melt), degassing of CO2 from the melt is negligible. In the latter scenario, the large fraction of vapor enclosed in the MI during trapping essentially serves as a buffer, preventing post-entrapment modification of volatile concentrations in the melt. Hence, the glass phase within such heterogeneously entrapped, vapor-rich MI records the volatile concentrations of the melt at the time of trapping. These numerical modeling results suggest that heterogeneously entrapped MI containing large vapor bubbles represent amenable samples for constraining pre-eruptive volatile concentrations of subvolcanic melts.

First experimental observations on melting and chemical modification of volcanic ash during lightning interaction.

PubMed

Mueller, S P; Helo, C; Keller, F; Taddeucci, J; Castro, J M

2018-01-23

Electrification in volcanic ash plumes often leads to syn-eruptive lightning discharges. High temperatures in and around lightning plasma channels have the potential to chemically alter, re-melt, and possibly volatilize ash fragments in the eruption cloud. In this study, we experimentally simulate temperature conditions of volcanic lightning in the laboratory, and systematically investigate the effects of rapid melting on the morphology and chemical composition of ash. Samples of different size and composition are ejected towards an artificially generated electrical arc. Post-experiment ash morphologies include fully melted spheres, partially melted particles, agglomerates, and vesiculated particles. High-speed imaging reveals various processes occurring during the short lightning-ash interactions, such as particle melting and rounding, foaming, and explosive particle fragmentation. Chemical analyses of the flash-melted particles reveal considerable bulk loss of Cl, S, P and Na through thermal vaporization. Element distribution patterns suggest convection as a key process of element transport from the interior of the melt droplet to rim where volatiles are lost. Modeling the degree of sodium loss delivers maximum melt temperatures between 3290 and 3490 K. Our results imply that natural lighting strikes may be an important agent of syn-eruptive morphological and chemical processing of volcanic ash.

Chemical systematics of the Shergotty meteorite and the composition of its parent body (Mars)

NASA Technical Reports Server (NTRS)

Laul, J. C.; Smith, M. R.; Waenke, H.; Jagoutz, E.; Dreibus, G.

1986-01-01

Sixty elements in two bulk samples of Shergotty meteorite and 30 elements in various mineral separates of Shergotty were identified, using mainly INAA and RNAA techniques. In addition, elements leached out from powdered samples of Shergotty and EETA 79001 meteorites by 0.1 N HCl, as well as the elements of their residues, were analyzed. The results have indicated that Shergotty meteorite is homogeneous in its major element composition, but heterogeneous with respect to large-ion lithophile elements, such as K, Ba, Sr, Zr, Hf, Ta, Th, and rare-earth elements (REEs). It is even more heterogeneous with respect to volatile elements, such as Cd, Te, Tl, and Bi, and the siderophiles Au and Ag. The REE patterns of the Shergotty and EETA 79001 residues are identical, indicating that the parent magmas of both meteorites are compositionally similar. However, their leachate (phosphate) patterns are different, suggesting two components for the Shergotty, one of which is similar to the EETA 79001 leachate.

Elemental compositions of two extrasolar rocky planetesimals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, S.; Jura, M.; Klein, B.

2014-03-10

We report Keck/HIRES and Hubble Space Telescope/COS spectroscopic studies of extrasolar rocky planetesimals accreted onto two hydrogen atmosphere white dwarfs, G29-38 and GD 133. In G29-38, eight elements are detected, including C, O, Mg, Si, Ca, Ti, Cr, and Fe while in GD 133, O, Si, Ca, and marginally Mg are seen. These two extrasolar planetesimals show a pattern of refractory enhancement and volatile depletion. For G29-38, the observed composition can be best interpreted as a blend of a chondritic object with some refractory-rich material, a result from post-nebular processing. Water is very depleted in the parent body accreted ontomore » G29-38, based on the derived oxygen abundance. The inferred total mass accretion rate in GD 133 is the lowest of all known dusty white dwarfs, possibly due to non-steady state accretion. We continue to find that a variety of extrasolar planetesimals all resemble to zeroth order the elemental composition of bulk Earth.« less

Collisional erosion and the non-chondritic composition of the terrestrial planets.

PubMed

O'Neill, Hugh St C; Palme, Herbert

2008-11-28

The compositional variations among the chondrites inform us about cosmochemical fractionation processes during condensation and aggregation of solid matter from the solar nebula. These fractionations include: (i) variable Mg-Si-RLE ratios (RLE: refractory lithophile element), (ii) depletions in elements more volatile than Mg, (iii) a cosmochemical metal-silicate fractionation, and (iv) variations in oxidation state. Moon- to Mars-sized planetary bodies, formed by rapid accretion of chondrite-like planetesimals in local feeding zones within 106 years, may exhibit some of these chemical variations. However, the next stage of planetary accretion is the growth of the terrestrial planets from approximately 102 embryos sourced across wide heliocentric distances, involving energetic collisions, in which material may be lost from a growing planet as well as gained. While this may result in averaging out of the 'chondritic' fractionations, it introduces two non-chondritic chemical fractionation processes: post-nebular volatilization and preferential collisional erosion. In the latter, geochemically enriched crust formed previously is preferentially lost. That post-nebular volatilization was widespread is demonstrated by the non-chondritic Mn/Na ratio in all the small, differentiated, rocky bodies for which we have basaltic samples, including the Moon and Mars. The bulk silicate Earth (BSE) has chondritic Mn/Na, but shows several other compositional features in its pattern of depletion of volatile elements suggestive of non-chondritic fractionation. The whole-Earth Fe/Mg ratio is 2.1+/-0.1, significantly greater than the solar ratio of 1.9+/-0.1, implying net collisional erosion of approximately 10 per cent silicate relative to metal during the Earth's accretion. If this collisional erosion preferentially removed differentiated crust, the assumption of chondritic ratios among all RLEs in the BSE would not be valid, with the BSE depleted in elements according to their geochemical incompatibility. In the extreme case, the Earth would only have half the chondritic abundances of the highly incompatible, heat-producing elements Th, U and K. Such an Earth model resolves several geochemical paradoxes: the depleted mantle occupies the whole mantle, is completely outgassed in (40)Ar and produces the observed (4)He flux through the ocean basins. But the lower radiogenic heat production exacerbates the discrepancy with heat loss.

Chemical and mineralogical size segregation in the impact disruption of inhomogeneous, anhydrous meteorites

NASA Astrophysics Data System (ADS)

Flynn, George J.; Durda, Daniel D.

2004-10-01

We performed impact disruption experiments on pieces from eight different anhydrous chondritic meteorites - four weathered ordinary chondrite finds from North Africa (NWA791, NWA620, NWA869 and MOR001), three almost unweathered ordinary chondrite falls (Mbale, Gao, and Saratov), and an almost unweathered carbonaceous chondrite fall (Allende). In each case the impactor was a small (1/8 or 1/4 in) aluminum sphere fired at the meteorite target at ˜5km/s, comparable to the mean collision speed in the main-belt. Some of the ˜5 to ˜150μm debris from each disruption was collected in aerogel capture cells, and the captured particles were analyzed by in situ synchrotron-based X-ray fluorescence. For each meteorite, many of the smallest particles ( <10μm up to 35μm in size, depending on the meteorite) exhibit very high Ni/Fe ratios compared to the Ni/Fe ratios measured in the larger particles (>45μm), a composition consistent with the smallest debris being dominated by matrix material while the larger debris is dominated by fragments from olivine chondrules. These results may explain why the ˜10μm interplanetary dust particles (IDPs) collected from the Earth's stratosphere are C-rich and volatile-rich compared to the presumed solar nebula composition. The ˜10μm IDPs may simply sample the matrix of an inhomogeneous parent body, structurally and mineralogically similar to the chondritic meteorites, which are inhomogeneous assemblages of compact, strong, C- and volatile-poor chondrules that are distributed in a more porous, C- and volatile-rich matrix. In addition, these results may explain why the micrometeorites, which are ˜50μm to millimeters in size, recovered from the polar ices are Ni- and S-poor compared to chondritic meteorites, since these polar micrometeorites may preferentially sample fragments from the Ni- and S-poor olivine chondrules. These results indicate that the average composition of the IDPs may be biased towards the composition of the matrix of the parent body while the average composition of the polar micrometeorites may be more heavily weighted towards the composition of the chondrules and clasts. Thus, neither the IDPs nor the polar micrometeorites may sample the bulk composition of their respective parent bodies. We determined the threshold collisional specific energy (QD*) for these chondritic meteorites to be 1419 J/kg, about twice the value for terrestrial basalt. Comparison of the mass of the largest fragment produced in the disruption of an ˜100g sample of the porous ordinary chondrite Saratov with the largest fragment produced in the disruption of an ˜100g sample of the compact ordinary chondrite MOR001 when each was struck by an impactor having approximately the same kinetic energy confirms that it requires significantly more energy to disrupt a porous target than a non-porous target. These results may also have important implications for the design of spacecraft missions intended to sample the composition and mineralogy of the chondritic asteroids and other inhomogeneous bodies. A Stardust-like spacecraft intended to sample asteroids by collecting only the small debris from a man-made impact onto the asteroid may collect particles that over-sample the matrix of the target and do not provide a representative sample of the bulk composition. The impact collection technique to be employed by the Japanese HAYABUSA (formerly MUSES-C) spacecraft to sample the asteroid Itokawa may result in similar mineral segregation.

Early and long-term mantle processing rates derived from xenon isotopes

NASA Astrophysics Data System (ADS)

Mukhopadhyay, S.; Parai, R.; Tucker, J.; Middleton, J. L.; Langmuir, C. H.

2015-12-01

Noble gases, particularly xenon (Xe), in mantle-derived basalts provide a rich portrait of mantle degassing and surface-interior volatile exchange. The combination of extinct and extant radioactive species in the I-Pu-U-Xe systems shed light on the degassing history of the early Earth throughout accretion, as well as the long-term degassing of the Earth's interior in association with plate tectonics. The ubiquitous presence of shallow-level air contamination, however, frequently obscures the mantle Xe signal. In a majority of the samples, shallow air contamination dominates the Xe budget. For example, in the gas-rich popping rock 2ΠD43, 129Xe/130Xe ratios reach 7.7±0.23 in individual step-crushes, but the bulk composition of the sample is close to air (129Xe/130Xe of 6.7). Thus, the extent of variability in mantle source Xe composition is not well-constrained. Here, we present new MORB Xe data and explore constraints placed on mantle processing rates by the Xe data. Ten step-crushes were obtained on a depleted popping glass that was sealed in ultrapure N2 after dredge retrieval from between the Kane-Atlantis Fracture Zone of the Mid Atlantic Ridge in May 2012. 9 steps yielded 129Xe/130Xe of 7.50-7.67 and one yielded 7.3. The bulk 129Xe/130Xe of the sample is 7.6, nearly identical to the estimated mantle source value of 7.7 for the sample. Hence, the sample is virtually free of shallow-level air contamination. Because sealing the sample in N2upon dredge retrieval largely eliminated air contamination, for many samples, contamination must be added after sample retrieval from the ocean bottom. Our new high-precision Xe isotopic measurements in upper mantle-derived samples provide improved constraints on the Xe isotopic composition of the mantle source. We developed a forward model of mantle volatile evolution to identify solutions that satisfy our Xe isotopic data. We find that accretion timescales of ~10±5 Myr are consistent with I-Pu-Xe constraints, and the last giant impact occurred 45-70 Myr after the start of the solar system. After the giant impact stage, the Pu-U-Xe system indicates that degassing of the planet via solid-state mantle convection and plate tectonics continued to liberate volatiles to the atmosphere and has led to between ~5-8 mantle turnovers over the age of the Earth.

Some aspects of composition of the lower Martian atmosphere: input for MIRA

NASA Astrophysics Data System (ADS)

Moroz, V.; Korablev, O.; Krasnopolsky, V.; Rorin, A.

Recent spacecraft missions and high-resolution spectroscopic observations from the Earth-based, airborne and spaceborne observatories have justified the chemical contents of the Martian atmosphere at a new level of confidence. Both the lower and middle atmosphere of Mars reveal very limited chemical activity, while the variations of the abundance of minor constituents may be attributed to phase transitions of volatiles. Water vapor, which mixing ratio is controlled by complex hydrological cycle in the lower atmosphere and at the surface of the planet, affects seasonally varying depletion of ozone. Measured ratio of D/H can be explained with general models of the early evolution of the planet, though this estimate in the bulk atmosphere may not be ultimately representative due to altitude dependant fractionation of water isotopes. CO, as a chemically passive nonvolatile component, reveals increase of mixing ratio in the vicinity of winter polar caps during active condensation of the bulk CO2 atmosphere. No reliable evidence o any organicf matter in the atmosphere of Mars has been obtained.

Volatile composition of coffee berries at different stages of ripeness and their possible attraction to the coffee berry borer Hypothenemus hampei (Coleoptera: Curculionidae).

PubMed

Ortiz, Américo; Ortiz, Aristófeles; Vega, Fernando E; Posada, Francisco

2004-09-22

The analysis of volatile emissions of coffee berries in different physiological states of ripeness was performed using dynamic headspace and gas chromatography/mass spectrometry analysis for Coffea arabica, var. Colombia. The composition of the volatiles emitted by coffee berries is dominated by very high levels of alcohols, mainly ethanol, in all stages of ripeness in comparison with other compounds. Overripe coffee berries have high volatile emissions and show a composition dominated mainly by esters followed by alcohols, ketones, and aldehydes. The lowest level compounds were monoterpenes. 2-Methyl furan was detected in various ripening stages; this compound has not been previously reported as a coffee berry volatile. The presence of ethanol and other alcohols in the volatile composition might explain the effectiveness of using traps with mixed alcohols for detection and capture of coffee berry borers.

Resource Prospector, the Decadal Survey and the Scientific Context for the Exploration of the Moon

NASA Technical Reports Server (NTRS)

Elphic, R. C.; Colaprete, A.; Andrews, D. R.

2017-01-01

The Inner Planets Panel of the Planetary Exploration Decadal Survey defined several science questions related to the origins, emplacement, and sequestration of lunar polar volatiles: 1. What is the lateral and vertical distribution of the volatile deposits? 2. What is the chemical composition and variability of polar volatiles? 3. What is the isotopic composition of the volatiles? 4. What is the physical form of the volatiles? 5. What is the rate of the current volatile deposition? A mission concept study, the Lunar Polar Volatiles Explorer (LPVE), defined a approximately $1B New Frontiers mission to address these questions. The NAS/NRC report, 'Scientific Context for the Exploration of the Moon' identified he lunar poles as special environments with important implications. It put forth the following goals: Science Goal 4a-Determine the compositional state (elemental, isotopic, mineralogic) and compositional distribution (lateral and depth) of the volatile component in lunar polar regions. Science Goal 4b-Determine the source(s) for lunar polar volatiles. Science Goal 4c-Understand the transport, retention, alteration, and loss processes that operate on volatile materials at permanently shaded lunar regions. Science Goal 4d-Understand the physical properties of the extremely cold (and possibly volatile rich) polar regolith. Science Goal 4e-Determine what the cold polar regolith reveals about the ancient solar environment.

A Simulated Chlorine-Saturated Lunar Magmatic System at the Surface and At Depth

NASA Astrophysics Data System (ADS)

DiFrancesco, N.; Nekvasil, H.; Lindsley, D. H.

2016-12-01

Analysis of igneous minerals present in lunar rocks has provided evidence that volatiles such as water, chlorine and fluorine were concentrated in melts present at or near the lunar surface. While at depth, pressure on a magma allows these gases to remain dissolved in a silicate liquid, however as the magma ascends and depressurizes, these components become saturated and begin exsolving. While at pressure, it's possible for these components, specifically Cl, to form complexes in the melt with major cations such as Na, K, and Fe as well as trace elements such as Zn and Li. While dissolved in the melt, it may be possible for the Cl to inhibit the ability for these cations to enter into crystalline phases such as olivine, plagioclase, or pyroxene, potentially altering the composition of minerals associated with the melt. As the magma rises, these compounds are able to boil off from the magma, changing its bulk composition by effectively removing these cations as halides in a vapor phase. The goals of this project are to experimentally ascertain the nature of minerals sublimated by this degassing, and the effects that this process may have on the evolution and liquid line of decent for a cooling lunar magma. This is accomplished by crystallizing volatile-rich synthetic lunar basalts both at high and zero pressure and analyzing both vapor deposits and solidified liquids. Experimental data simulating volatile-rich magma degassing and crystallization at the lunar surface, and within the lunar crust has demonstrated that typical KREEP basalts (potentially rich in Cl) will crystallize more magnesian and calcic phases at high pressure, and subsequently lose alkalis and iron to a vapor phase at low pressure. We see evidence of vapor deposits and volatile element enrichment in returned Apollo samples such as "Rusty Rock", and on the surface of orange glass beads.

Thermodynamic Parameterization of Subduction-Zone Devolatilization and Application to Quantify Carbon Fluxes from Slab

NASA Astrophysics Data System (ADS)

Tian, M.; Katz, R. F.; Rees Jones, D. W.; May, D.

2017-12-01

Compared with other plate-tectonic boundaries, subduction zones (SZ) host the most drastic mechanical, thermal, and chemical changes. The transport of carbon through this complex environment is crucial to mantle carbon budget but remains the subject of active debate. Synthesis of field studies suggests that carbon subducted with the incoming slab is almost completely returned to the surface environment [Kelemen and Manning, 2015], whereas thermodynamic modelling indicates that a significant portion of carbon is retained in the slab and descends into the deep mantle [Gorman et al., 2006]. To address this controversy and quantify the carbon fluxes within SZs, it is necessary to treat the chemistry of fluid/volatile-rock interaction and the mechanics of porous fluid/volatile migration in a consistent modelling framework. This requirement is met by coupling a thermodynamic parameterization of de/re-volatilization with a two-phase flow model of subduction zones. The two-phase system is assumed to comprise three chemical components: rock containing only non-volatile oxides, H2O and CO2; the fluid phase includes only the latter two. Perple_X is used to map out the binary subsystems rock+H2O and rock+CO2; the results are parameterised in terms of volatile partition coefficients as a function of pressure and temperature. In synthesising the binary subsystems to describe phase equilibria that incorporate all three components, a Margules coefficient is introduced to account for non-ideal mixing of CO2/H2O in the fluid, such that the partition coefficients depend further on bulk composition. This procedure is applied to representative compositions of sediment, MORB, and gabbro for the slab, and peridotite for the mantle. The derived parameterization of each rock type serves as a lightweight thermodynamic module interfaceable with two-phase flow models of SZs. We demonstrate the application of this thermodynamic module through a simple model of carbon flux with a prescribed flow direction through (and out of) the slab. This model allows us to evaluate the effects of flow path and lithology on carbon storage within the slab.

Characterisation of nano- and micron-sized airborne and collected subway particles, a multi-analytical approach.

PubMed

Midander, Klara; Elihn, Karine; Wallén, Anna; Belova, Lyuba; Karlsson, Anna-Karin Borg; Wallinder, Inger Odnevall

2012-06-15

Continuous daily measurements of airborne particles were conducted during specific periods at an underground platform within the subway system of the city center of Stockholm, Sweden. Main emphasis was placed on number concentration, particle size distribution, soot content (analyzed as elemental and black carbon) and surface area concentration. Conventional measurements of mass concentrations were conducted in parallel as well as analysis of particle morphology, bulk- and surface composition. In addition, the presence of volatile and semi volatile organic compounds within freshly collected particle fractions of PM(10) and PM(2.5) were investigated and grouped according to functional groups. Similar periodic measurements were conducted at street level for comparison. The investigation clearly demonstrates a large dominance in number concentration of airborne nano-sized particles compared to coarse particles in the subway. Out of a mean particle number concentration of 12000 particles/cm(3) (7500 to 20000 particles/cm(3)), only 190 particles/cm(3) were larger than 250 nm. Soot particles from diesel exhaust, and metal-containing particles, primarily iron, were observed in the subway aerosol. Unique measurements on freshly collected subway particle size fractions of PM(10) and PM(2.5) identified several volatile and semi-volatile organic compounds, the presence of carcinogenic aromatic compounds and traces of flame retardants. This interdisciplinary and multi-analytical investigation aims to provide an improved understanding of reported adverse health effects induced by subway aerosols. Copyright © 2012 Elsevier B.V. All rights reserved.

Temporal and Spatial Aspects of Gas Release During the 2010 Apparition of Comet 103P/Hartley-2

NASA Technical Reports Server (NTRS)

Mumma, M. J.; Bonev, B. P.; Villanueva, G. L.; Paganini, L.; DiSanti, M. A.; Gibb, E. L.; Keane, J. V.; Meech, K. J.; Blake, G. A.; Ellis, R. S.;

Comparative analysis of juice volatiles in selected mandarins, mandarin relatives and other citrus genotypes.

PubMed

Yu, Yuan; Bai, Jinhe; Chen, Chunxian; Plotto, Anne; Baldwin, Elizabeth A; Gmitter, Frederick G

2018-02-01

Citrus fruit flavor is an important attribute prioritized in variety improvement. The present study compared juice volatiles compositions from 13 selected citrus genotypes, including six mandarins (Citrus reticulata), three sour oranges (Citrus aurantium), one blood orange (Citrus sinensis), one lime (Citrus limonia), one Clementine (Citrus clementina) and one satsuma (Citrus unshiu). Large differences were observed with respect to volatile compositions among the citrus genotypes. 'Goutou' sour orange contained the greatest number of volatile compounds and the largest volatile production level. 'Ponkan' mandarin had the smallest number of volatiles and 'Owari' satsuma yielded the lowest volatile production level. 'Goutou' sour orange and 'Moro' blood orange were clearly distinguished from other citrus genotypes based on the analysis of volatile compositions, even though they were assigned into one single group with two other sour oranges by the molecular marker profiles. The clustering analysis based on the aroma volatile compositions was able to differentiate mandarin varieties and natural sub-groups, and was also supported by the molecular marker study. The gas chromatography-mass spectrometry analysis of citrus juice aroma volatiles can be used as a tool to distinguish citrus genotypes and assist in the assessment of future citrus breeding programs. The aroma volatile profiles of the different citrus genotypes and inter-relationships detected among volatile compounds and among citrus genotypes will provide fundamental information on the development of marker-assisted selection in citrus breeding. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Characterization of Inorganic Filler Content, Mechanical Properties, and Light Transmission of Bulk-fill Resin Composites.

PubMed

Fronza, B M; Ayres, Apa; Pacheco, R R; Rueggeberg, F A; Dias, Cts; Giannini, M

The aims of this study were to characterize inorganic content (IC), light transmission (LT), biaxial flexural strength (BFS), and flexural modulus (FM) of one conventional (layered) and four bulk-fill composites at different depths. Bulk-fill composites tested were Surefil SDR flow (SDR), Filtek Bulk Fill (FBF), Tetric EvoCeram Bulk Fill (TEC), and EverX Posterior (EXP). Herculite Classic (HER) was used as a control. Energy dispersive x-ray analysis and scanning electron microscopy were used to characterize filler particle composition and morphology. The LT through different composite thicknesses (1, 2, 3, and 4 mm) was measured using a laboratory-grade spectral radiometer system (n=5). For the BFS and FM tests, sets of eight stacked composite discs (0.5-mm thick) were prepared simulating bulk filling of a 4-mm-thick increment (n=8). SDR demonstrated larger, irregular particles than those observed in TEC or HER. Filler particles in FBF were spherical, while those in EXP were composed of fiberglass strands. The LT decreased with increased composite thickness for all materials. Bulk-fill composites allowed higher LT than the HER. Furthermore, HER proved to be the unique material, having lower BFS values at deeper regions. SDR, FBF, and TEC bulk-fill composites presented reduced FM with increasing composite depth. The bulk-fill composites investigated exhibited higher LT, independent of different filler content and characteristics. Although an increase in composite thickness reduced LT, the BFS of bulk-fill composites at deeper layers was not compromised.

The Sands of the Bagnold Dunes, Mars and Volatiles in Mars Soils

NASA Astrophysics Data System (ADS)

Ehlmann, B. L.; Edgett, K. S.; Sutter, B.; Achilles, C.; Litvak, M. L.; Lapotre, M. G. A.; Sullivan, R. J., Jr.; Fraeman, A. A.; Arvidson, R. E.; Blake, D. F.; Bridges, N. T.; Conrad, P. G.; Cousin, A.; Downs, R. T.; Gabriel, T. S. J.; Gellert, R.; Hamilton, V. E.; Hardgrove, C. J.; Johnson, J. R.; Kuhn, S.; Mahaffy, P. R.; Maurice, S.; Meslin, P. Y.; McHenry, M.; Ming, D. W.; Minitti, M. E.; Morookian, J.; Morris, R. V.; O'Connell-Cooper, C.; Pinet, P. C.; Rowland, S. K.; Schröder, S.; Siebach, K. L.; Stein, N.; Thompson, L. M.; Vaniman, D.; Vasavada, A. R.; Wellington, D. F.; Wiens, R. C.; Yen, A.

2017-12-01

The Mars Science Laboratory Curiosity rover performed coordinated measurements to examine the textures and compositions of aeolian sands in an active portion of the Bagnold dune field. The composition and grain size information were reviewed in Ehlmann et al. [2017, JGR-Planets and papers referenced therein]. The Bagnold sands are rounded to subrounded, very fine to medium sized ( 45-500 μm) with ≥6 distinct grain colors. In contrast to sands examined by Curiosity in a dust-covered, inactive bedform called Rocknest and soils at other landing sites, Bagnold sands are darker, less red, better sorted, have fewer silt-sized or smaller grains, and show no evidence for cohesion. Nevertheless, Bagnold mineralogy and Rocknest mineralogy are similar with plagioclase, olivine, and pyroxenes in similar proportions comprising >90% of crystalline phases, along with a substantial amorphous component (35% ± 15%) [Achilles et al., 2017]. Like Rocknest, release of CO2 and NO is higher than Gale rocks, implying enrichment in the carrier phases of these volatiles [Sutter et al., 2017]. Yet Bagnold and Rocknest bulk chemistries differ. Bagnold sands are Si-enriched relative to other soils at Gale crater [Cousin et al., 2017; O'Connell-Cooper et al., 2017], and H2O, S, and Cl are lower relative to all previously measured Martian soils and most Gale crater rocks. Mg, Ni, Fe, and Mn are enriched in the coarse-sieved fraction of Bagnold sands [Cousin et al., 2017; O'Connell-Cooper et al., 2017], corroborated by visible/near-infrared spectra that suggest enrichment of olivine [Johnson et al., 2017]. Collectively, patterns in major element chemistry and volatile release data indicate two distinctive volatile reservoirs in Martian soils: (1) amorphous components in the sand-sized fraction (represented by Bagnold) that are Si-enriched, hydroxylated alteration products and/or impact or volcanic glasses and (2) amorphous components in the fine fraction (<40 μm; represented by Rocknest and other bright soils) that are Fe, S, and Cl enriched with low Si and adsorbed and structural H2O. This has implications for the origins of the volatiles and their potential extractability. Future isotopic measurements of later-acquired sand samples may help elucidate the origins and timing of the volatiles sequestration in Martian sands and soils.

Abundances of sodium, sulfur, and potassium in lunar volcanic glasses: Evidence for volatile loss during eruption

NASA Technical Reports Server (NTRS)

Delano, J. W.; Mcguire, J.

1992-01-01

Six varieties of lunar volcanic glass are known to occur within the Apollo 17 sample collection. Investigations have shown that 25 volatile elements are known to be concentrated on the exterior surfaces of individual volcanic glass spheres. Since bulk analyses of volcanic glass provide an integrated abundance of an element on and with the glass spherules, other methods must be relied on to determine the interior abundance of an element. The interior abundance of an element with a volcanic glass sphere establishes the abundance of that element in the melt at the time of quench. The current study is part of a comprehensive attempt to measure the abundance of three volatile elements (Na, S, and K) within representative spheres of the 25 varieties of lunar volcanic glass currently known to exist at the Apollo landing sites. Comparison of the measured abundances of these elements within the interiors of individual glasses with bulk analyses and crystalline mare basalts will furnish new constraints on the geochemical behavior of volatile elements during lunar mare volcanism.

Earth’s Earliest Atmospheres

PubMed Central

Zahnle, Kevin; Schaefer, Laura; Fegley, Bruce

2010-01-01

Earth is the one known example of an inhabited planet and to current knowledge the likeliest site of the one known origin of life. Here we discuss the origin of Earth’s atmosphere and ocean and some of the environmental conditions of the early Earth as they may relate to the origin of life. A key punctuating event in the narrative is the Moon-forming impact, partly because it made Earth for a short time absolutely uninhabitable, and partly because it sets the boundary conditions for Earth’s subsequent evolution. If life began on Earth, as opposed to having migrated here, it would have done so after the Moon-forming impact. What took place before the Moon formed determined the bulk properties of the Earth and probably determined the overall compositions and sizes of its atmospheres and oceans. What took place afterward animated these materials. One interesting consequence of the Moon-forming impact is that the mantle is devolatized, so that the volatiles subsequently fell out in a kind of condensation sequence. This ensures that the volatiles were concentrated toward the surface so that, for example, the oceans were likely salty from the start. We also point out that an atmosphere generated by impact degassing would tend to have a composition reflective of the impacting bodies (rather than the mantle), and these are almost without exception strongly reducing and volatile-rich. A consequence is that, although CO- or methane-rich atmospheres are not necessarily stable as steady states, they are quite likely to have existed as long-lived transients, many times. With CO comes abundant chemical energy in a metastable package, and with methane comes hydrogen cyanide and ammonia as important albeit less abundant gases. PMID:20573713

Earth's earliest atmospheres.

PubMed

Zahnle, Kevin; Schaefer, Laura; Fegley, Bruce

2010-10-01

Earth is the one known example of an inhabited planet and to current knowledge the likeliest site of the one known origin of life. Here we discuss the origin of Earth's atmosphere and ocean and some of the environmental conditions of the early Earth as they may relate to the origin of life. A key punctuating event in the narrative is the Moon-forming impact, partly because it made Earth for a short time absolutely uninhabitable, and partly because it sets the boundary conditions for Earth's subsequent evolution. If life began on Earth, as opposed to having migrated here, it would have done so after the Moon-forming impact. What took place before the Moon formed determined the bulk properties of the Earth and probably determined the overall compositions and sizes of its atmospheres and oceans. What took place afterward animated these materials. One interesting consequence of the Moon-forming impact is that the mantle is devolatized, so that the volatiles subsequently fell out in a kind of condensation sequence. This ensures that the volatiles were concentrated toward the surface so that, for example, the oceans were likely salty from the start. We also point out that an atmosphere generated by impact degassing would tend to have a composition reflective of the impacting bodies (rather than the mantle), and these are almost without exception strongly reducing and volatile-rich. A consequence is that, although CO- or methane-rich atmospheres are not necessarily stable as steady states, they are quite likely to have existed as long-lived transients, many times. With CO comes abundant chemical energy in a metastable package, and with methane comes hydrogen cyanide and ammonia as important albeit less abundant gases.

Volatile components of vine leaves from two Portuguese grape varieties (Vitis vinifera L.), Touriga Nacional and Tinta Roriz, analysed by solid-phase microextraction.

PubMed

Fernandes, Bruno; Correia, Ana C; Cosme, Fernanda; Nunes, Fernando M; Jordão, António M

2015-01-01

The purpose of this work was to study the volatile composition of vine leaves and vine leaf infusion prepared from vine leaves collected at 30 and 60 days after grape harvest of two Vitis vinifera L. species. Eighteen volatile compounds were identified by gas chromatography-mass spectrometry in vine leaves and in vine leaf infusions. It was observed that the volatile compounds present in vine leaves are dependent on the time of harvest, with benzaldehyde being the major volatile present in vine leaves collected at 30 days after harvesting. There are significant differences in the volatile composition of the leaves from the two grape cultivars, especially in the sample collected at 60 days after grape harvest. This is not reflected in the volatile composition of the vine leaf infusion made from this two cultivars, the more important being the harvesting date for the volatile profile of vine leaf infusion than the vine leaves grape cultivar.

Microtensile bond strength of bulk-fill restorative composites to dentin.

PubMed

Mandava, Jyothi; Vegesna, Divya-Prasanna; Ravi, Ravichandra; Boddeda, Mohan-Rao; Uppalapati, Lakshman-Varma; Ghazanfaruddin, M D

2017-08-01

To facilitate the easier placement of direct resin composite in deeper cavities, bulk fill composites have been introduced. The Mechanical stability of fillings in stress bearing areas restored with bulk-fill resin composites is still open to question, since long term clinical studies are not available so far. Thus, the objective of the study was to evaluate and compare the microtensile bond strength of three bulk-fill restorative composites with a nanohybrid composite. Class I cavities were prepared on sixty extracted mandibular molars. Teeth were divided into 4 groups (n= 15 each) and in group I, the prepared cavities were restored with nanohybrid (Filtek Z250 XT) restorative composite in an incremental manner. In group II, III and IV, the bulk-fill composites (Filtek, Tetric EvoCeram, X-tra fil bulk-fill restoratives) were placed as a 4 mm single increment and light cured. The restored teeth were subjected to thermocycling and bond strength testing was done using instron testing machine. The mode of failure was assessed by scanning electron microscope (SEM). The bond strength values obtained in megapascals (MPa) were subjected to statistical analysis, using SPSS/PC version 20 software.One-way ANOVA was used for groupwise comparison of the bond strength. Tukey's Post Hoc test was used for pairwise comparisons among the groups. The highest mean bond strength was achieved with Filtek bulk-fill restorative showing statistically significant difference with Tetric EvoCeram bulk-fill ( p < 0.003) and X-tra fil bulk-fill ( p <0.001) composites. Adhesive failures are mostly observed with X-tra fil bulk fill composites, whereas mixed failures are more common with other bulk fill composites. Bulk-fill composites exhibited adequate bond strength to dentin and can be considered as restorative material of choice in posterior stress bearing areas. Key words: Bond strength, Bulk-fill restoratives, Configuration factor, Polymerization shrinkage.

Passive degassing at Nyiragongo (D.R. Congo) and Etna (Italy) volcanoes: the chemical characterization of the emissions and assessment of their uptake of trace elements emissions on the local environment

NASA Astrophysics Data System (ADS)

Calabrese, Sergio; Scaglione, Sarah; Milazzo, Silvia; D'Alessandro, Walter; Bobrowski, Nicole; Giuffrida, Giovanni; Tedesco, Dario; Parello, Francesco

2014-05-01

Volcanoes are well known as an impressive large natural source of trace elements into the troposphere. Among others, Etna (Italy) and Nyiragongo (D.R. Congo), two noteworthy emitters on Earth, are two stratovolcanoes located in different geological settings, both characterized by persistent passive degassing from their summit craters. Here, we present some results on trace element composition in volcanic plume emissions, atmospheric bulk deposition (rainwater) and their uptake of the surrounding vegetation, with the aim to compare and identify differences and similarities between this these two volcanoes. Volcanic emissions were sampled by using active filter-pack for acid gases (sulfur and halogens) and specific teflon filters for particulates (major and trace elements). The impact of the volcanogenic deposition in the surrounding of the crater rims was investigated by using different sampling techniques: bulk rain collectors gauges were used to collect atmospheric bulk deposition, and biomonitoring technique was carried out to collect gases and particulates by using endemic plant species. Concentrations of major and trace elements of volcanic plume emissions (gases and particulates) were obtained by elution and microwave digestion of the collected filters: sulfur and halogens were determined by ion chromatography and ICP-MS, and untreated filters for particulate were acid digested and analysed by ICP-OES and ICP-MS. Rain water and plant samples were also analysed for major and trace elements by using ICP-OES and ICP-MS. In total 55 elements were determined. The estimates of the trace element fluxes confirm that Etna and Nyiragongo are large sources of metals to the atmosphere, especially considering their persistent state of passive degassing. In general, chemical composition of the volcanic aerosol particles of both volcanoes is characterized by two main components: one is related to the silicic component produced by magma bursting and fragmentation, enriching the plume in Si, Al, Fe, Ti, Mg, Ca, Na, K and other trace elements like Ni, Cr, Co, Th and U; another one components, is dominated by volatile trace elements (As, Bi, Cd, Cu, Hg, Se, Te, Tl) related to the gas volatile phase (H2O, CO2, SO2, HCl, HF) and transported to the atmosphere mainly as hydro-soluble salts and/or in gaseous form in some cases. The large amount of emitted trace elements have a strong impact on the close surrounding of both volcanoes. This is clearly reflected by in the chemical composition of rain water collected at the summit areas both for Etna and Nyiragongo. In fact, rain water samples have low pH values (<2) and high concentrations of dissolved toxic metals. Moreover, the biomonitoring results highlight that bioaccumulation of trace elements is extremely high in the proximity of the crater rim and decreases with the distance from the active craters. In particular, we found a good correlation between volatile elements (Tl, As, Bi, Cd, Se, Cu) concentrations in the leaves of Senecio species collected in on both volcanoes, showing a clear influence of volcanic deposition.

Microencapsulation of Nigella sativa oleoresin by spray drying for food and nutraceutical applications.

PubMed

Edris, Amr E; Kalemba, Danuta; Adamiec, Janusz; Piątkowski, Marcin

2016-08-01

Oleoresin of Nigella sativa L. (Black cumin) was obtained from the seeds using hexane extraction at room temperature. The oleoresin was emulsified in an aqueous solution containing gum Arabic/maltodextrin (1:1 w/w) and then encapsulated in powder form by spray drying. The characteristics of the obtained powder including moisture content, bulk density, wettability, morphology, encapsulation efficiency were evaluated. The effect of the spray drying on the chemical composition of the volatile oil fraction of N. sativa oleoresin was also evaluated using gas chromatographic-mass spectroscopic analysis. Results indicated that the encapsulation efficiency of the whole oleoresin in the powder can range from 84.2±1.5% to 96.2±0.2% depending on the conditions of extracting the surface oil from the powder. On the other hand the encapsulation efficiency of the volatile oil fraction was 86.2% ±4.7. The formulated N. sativa L. oleoresin powder can be used in the fortification of processed food and nutraceuticals. Copyright © 2016 Elsevier Ltd. All rights reserved.

Finite-size effect and the components of multifractality in transport economics volatility based on multifractal detrending moving average method

NASA Astrophysics Data System (ADS)

Chen, Feier; Tian, Kang; Ding, Xiaoxu; Miao, Yuqi; Lu, Chunxia

2016-11-01

Analysis of freight rate volatility characteristics attracts more attention after year 2008 due to the effect of credit crunch and slowdown in marine transportation. The multifractal detrended fluctuation analysis technique is employed to analyze the time series of Baltic Dry Bulk Freight Rate Index and the market trend of two bulk ship sizes, namely Capesize and Panamax for the period: March 1st 1999-February 26th 2015. In this paper, the degree of the multifractality with different fluctuation sizes is calculated. Besides, multifractal detrending moving average (MF-DMA) counting technique has been developed to quantify the components of multifractal spectrum with the finite-size effect taken into consideration. Numerical results show that both Capesize and Panamax freight rate index time series are of multifractal nature. The origin of multifractality for the bulk freight rate market series is found mostly due to nonlinear correlation.

A numerical model to simulate foams during devolatilization of polymers

NASA Astrophysics Data System (ADS)

Khan, Irfan; Dixit, Ravindra

2014-11-01

Customers often demand that the polymers sold in the market have low levels of volatile organic compounds (VOC). Some of the processes for making polymers involve the removal of volatiles to the levels of parts per million (devolatilization). During this step the volatiles are phase separated out of the polymer through a combination of heating and applying lower pressure, creating foam with the pure polymer in liquid phase and the volatiles in the gas phase. The efficiency of the devolatilization process depends on predicting the onset of solvent phase change in the polymer and volatiles mixture accurately based on the processing conditions. However due to the complex relationship between the polymer properties and the processing conditions this is not trivial. In this work, a bubble scale model is coupled with a bulk scale transport model to simulate the processing conditions of polymer devolatilization. The bubble scale model simulates the nucleation and bubble growth based on the classical nucleation theory and the popular ``influence volume approach.'' As such it provides the information of bubble size distribution and number density inside the polymer at any given time and position. This information is used to predict the bulk properties of the polymer and its behavior under the applied processing conditions. Initial results of this modeling approach will be presented.

Volatility and leachability of heavy metals and radionuclides in thermally treated HEPA filter media generated from nuclear facilities.

PubMed

Yoon, In-Ho; Choi, Wang-Kyu; Lee, Suk-Chol; Min, Byung-Youn; Yang, Hee-Chul; Lee, Kune-Woo

2012-06-15

The purpose of the present study was to apply thermal treatments to reduce the volume of HEPA filter media and to investigate the volatility and leachability of heavy metals and radionuclides during thermal treatment. HEPA filter media were transformed to glassy bulk material by thermal treatment at 900°C for 2h. The most abundant heavy metal in the HEPA filter media was Zn, followed by Sr, Pb and Cr, and the main radionuclide was Cs-137. The volatility tests showed that the heavy metals and radionuclides in radioactive HEPA filter media were not volatilized during the thermal treatment. PCT tests indicated that the leachability of heavy metals and radionuclides was relatively low compared to those of other glasses. XRD results showed that Zn and Cs reacted with HEPA filter media and were transformed into crystalline willemite (ZnO·SiO(2)) and pollucite (Cs(2)OAl(2)O(3)4SiO(2)), which are not volatile or leachable. The proposed technique for the volume reduction and transformation of radioactive HEPA filter media into glassy bulk material is a simple and energy efficient procedure without additives that can be performed at relatively low temperature compared with conventional vitrification process. Copyright © 2012 Elsevier B.V. All rights reserved.

Comparison of the constituents of two jet engine lubricating oils and their volatile pyrolytic degradation products.

PubMed

van Netten, C; Leung, V

2000-03-01

Leaking oil seals in jet engines, at locations prior to the compressor stage, can be a cause of smoke in the cabins of BAe-146 aircraft. Compressed combustion air is bled off to pressurize the cabin and to provide a source of fresh air. Bleed air is diverted from a location just prior to the combustion chamber at a temperature around 500 degrees C. To prevent oil breakdown products from entering the cabin air, catalytic converters have been used to clean the air. During an oil seal failure this device becomes overloaded and smoke is observed in the cabin. Some aircraft companies have removed the catalytic converters and claim an improvement in air quality. During an oil seal failure, however, the flight crew is potentially exposed to the thermal breakdown products of the engine oils. Because very little is known regarding the thermal breakdown products of jet engine lubrication oils, two commercially available oils were investigated under laboratory conditions at 525 degrees C to measure the release of CO, CO2,NO2, and HCN as well as volatiles which were analyzed using GC-Mass spectrometry in an attempt to see if the neurotoxic agents tricresyl phosphates (TCPs) and trimethyl propane phosphate (TMPP) would be present or formed. TMPP was not found in these experiments. Some CO2 was generated along with CO which reached levels in excess of 100 ppm. HCN and NO2 were not detected. GC compositions of the two bulk oils and their breakdown products were almost identical. The presence of TCPs was confirmed in the bulk oils and in the volatiles. Localized condensation in the ventilation ducts and filters in the air conditioning packs are likely the reason why the presence of TCPs has not been demonstrated in cabin air. It was recommended that this needed to be verified in aircraft.

Neutron Spectrometer Prospecting in the Mojave Volatiles Project Analog Field Test

NASA Technical Reports Server (NTRS)

Elphic, R. C.; Heldmann, J. L.; Colaprete, A.; Hunt, D. R.; Deans, M. C.; Lim, D. S.; Foil, G.; Fong, T.

2015-01-01

We know that volatiles are sequestered at the poles of the Moon. While we have evidence of water ice and a number of other compounds based on remote sensing, the detailed distribution, and physical and chemical form are largely unknown. Additional orbital studies of lunar polar volatiles may yield further insights, but the most important next step is to use landed assets to fully characterize the volatile composition and distribution at scales of tens to hundreds of meters. To achieve this range of scales, mobility is needed. Because of the proximity of the Moon, near real-time operation of the surface assets is possible, with an associated reduction in risk and cost. This concept of operations is very different from that of rovers on Mars, and new operational approaches are required to carry out such real-time robotic exploration. The Mojave Volatiles Project (MVP) was a Moon-Mars Analog Mission Activities (MMAMA) program project aimed at (1) determining effective approaches to operating a real-time but short-duration lunar surface robotic mission, and (2) performing prospecting science in a natural setting, as a test of these approaches. Here we describe some results from the first such test, carried out in the Mojave Desert between 16 and 24 October, 2014. The test site was an alluvial fan just E of the Soda Mountains, SW of Baker, California. This site contains desert pavements, ranging from the late Pleistocene to early-Holocene in age. These pavements are undergoing dissection by the ongoing development of washes. A principal objective was to determine the hydration state of different types of desert pavement and bare ground features. The mobility element of the test was provided by the KREX-2 rover, designed and operated by the Intelligent Robotics Group at NASA Ames Research Center. The rover-borne neutron spectrometer measured the neutron albedo at both thermal and epithermal energies. Assuming uniform geochemistry and material bulk density, hydrogen as either hydroxyl/water in mineral assemblages or as moisture will significantly enhance the return of thermalized neutrons. However, in the Mojave test setting there is little uniformity, especially in bulk material density. We find that lighter toned materials (immature pavements, bar and swale, and wash materials) have lower thermal neutron flux, while mature, darker pavements with the greatest desert varnish development have higher neutron fluxes. Preliminary analysis of samples from the various terrain types in the test area indicates a prevailing moisture content of 2-3 wt% H2O. However, soil mineralogy suggests that the welldeveloped Av1 soil horizon beneath the topmost dark pavement clast layer contains the highest clay content. Structural water (including hydroxyl) in these clays may explain the enhanced neutron albedo over dark pavements. On the other hand, surface and subsurface bulk density can also play a role in neutron albedo - lower density of materials found in washes, for example, can result in a reduction in neutron flux. Analysis is ongoing.

Volatiles in Inter-Specific Bacterial Interactions

PubMed Central

Tyc, Olaf; Zweers, Hans; de Boer, Wietse; Garbeva, Paolina

2015-01-01

The importance of volatile organic compounds for functioning of microbes is receiving increased research attention. However, to date very little is known on how inter-specific bacterial interactions effect volatiles production as most studies have been focused on volatiles produced by monocultures of well-described bacterial genera. In this study we aimed to understand how inter-specific bacterial interactions affect the composition, production and activity of volatiles. Four phylogenetically different bacterial species namely: Chryseobacterium, Dyella, Janthinobacterium, and Tsukamurella were selected. Earlier results had shown that pairwise combinations of these bacteria induced antimicrobial activity in agar media whereas this was not the case for monocultures. In the current study, we examined if these observations were also reflected by the production of antimicrobial volatiles. Thus, the identity and antimicrobial activity of volatiles produced by the bacteria were determined in monoculture as well in pairwise combinations. Antimicrobial activity of the volatiles was assessed against fungal, oomycetal, and bacterial model organisms. Our results revealed that inter-specific bacterial interactions affected volatiles blend composition. Fungi and oomycetes showed high sensitivity to bacterial volatiles whereas the effect of volatiles on bacteria varied between no effects, growth inhibition to growth promotion depending on the volatile blend composition. In total 35 volatile compounds were detected most of which were sulfur-containing compounds. Two commonly produced sulfur-containing volatile compounds (dimethyl disulfide and dimethyl trisulfide) were tested for their effect on three target bacteria. Here, we display the importance of inter-specific interactions on bacterial volatiles production and their antimicrobial activities. PMID:26733959

Compositional Data for Bengal Delta Sediment Collected from a Borehole at Rajoir, Bangladesh

USGS Publications Warehouse

Breit, George N.; Yount, James C.; Uddin, Md. Nehal; Muneem, Ad. Atual; Lowers, Heather; Berry, Cyrus J.; Whitney, John W.

2007-01-01

Processes active within sediment of the Bengal basin have attracted world concern because of the locally high content of arsenic dissolved in ground water drawn from that sediment. Sediment samples were collected from a borehole in the town of Rajoir, Rajoir upazila, Madaripur district, Bangladesh, to investigate the processes contributing to arsenic contamination. The samples were mineralogically and chemically analyzed to determine compositional variations related to the arsenic content of the sediment. Mineralogy of the sediment was determined using powder X-ray diffraction. Bulk chemical composition was measured by Combustion; Inductively Coupled Plasma Atomic Emission Spectroscopy; Energy Dispersive X-ray Fluorescence; and Hydride Generation Atomic Absorption Spectrophotometry. Sediment was treated with 0.5 N HCl and resulting solutions were analyzed, primarily to evaluate the abundance and oxidation state of acid-soluble iron. Acid-volatile sulfide, acid-soluble sulfate, and reducible sulfide were also measured on a few samples. Sediment sampled at Rajoir is typically unlithified, gray, micaceous, feldspathic arenaceous sand with a few silt and clay layers. Arsenic content of the sediment ranges from 0.6 to 21 ppm with a median of 1.2 ppm.

Effect of volatile removal during molding on the properties of two phenolic-fiber composites

NASA Technical Reports Server (NTRS)

Price, H. L.; Lucy, M. H.

1974-01-01

A comparison has been made of the effect of three volatile-removing techniques during molding on the properties of phenolic-fiber composites. The first technique involved heating the molding compound from one side, initiating the volatile-producing reactions, and driving these volatiles through the compound toward the cooler side. The second technique involved the application of a vacuum to the molding cavity before and during the cure cycle. The third technique was a combination of the first two. These techniques were used in the compression molding of phenolic-asbestos and phenolic-glass composites. The effects of both the individual and combined techniques on the mechanical, thermal, and sorption properties of the composites are reported.

Neon isotopes show that Earth was accreted from irradiated material

NASA Astrophysics Data System (ADS)

Moreira, M. A.

2015-12-01

Since the 1980s, the notion that the Earth's mantle has a "solar" isotopic signature for neon has been favoured. Indeed, the 20Ne/22Ne ratio is above 12.5 in the mantle sources of OIB and MORB, close to the solar composition (13.4 for the Sun or 13.8 for the solar wind) and different from both atmospheric and chondritic compositions (Phase Q, Neon A). The most well accepted process invoked to explain this observed solar composition in the mantle is dissolution into a magma ocean of solar gases captured by gravity around the proto-Earth. However, Earth was accreted after gas from the proto-planetary disk had evaporated, suggesting that Earth itself could not have captured such a solar primordial atmosphere. Only planetary embryos were formed when the gas was still present in the disk. However, these planetary embryos with the mass of Mars are not massive enough to capture a solar dense atmosphere able to incorporate enough neon into the mantle. New estimates of the neon isotopic compositions of both the Earth's mantle and of the implanted solar wind into grains suggest that the origin of the neon on Earth is related to solar wind irradiation on μm grains before planetary accretion started and not dissolution. Although incorporation of solar ions by this process is only significant for very volatiles (depleted) elements, the irradiation by x-rays has important consequences for the bulk chemistry of irradiated grains as it has been demonstrated that it produces depletion in Mg and Si, relatively to O (e.g Bradley et al., 1994), a pattern also observed for the Bulk silicate Earth. References Bradley, J. (1994). "Chemically Anomalous, Preaccretionally irradiated Grains in Interplanetary fust from Comets." Science 265: 925-929.

Element Abundances in Meteorites and the Earth: Implication for the Accretion of Planetary Bodies

NASA Astrophysics Data System (ADS)

Mezger, K.; Vollstaedt, H.; Maltese, A.

2017-12-01

Essentially all known inner solar system materials show near chondritic relative abundances of refractory elements and depletion in volatile elements. To a first approximation volatile element depletion correlates with the respective condensation temperature (TC) of the elements. Possible mechanisms for this depletion are incomplete condensation and partial loss by evaporation caused by heating prior to or during the planetesimal accretion. The stable isotope compositions of almost all moderately volatile elements in different meteorite classes show only minor, or no evidence for a Rayleigh-type fractionation that could be attributed to partial condensation or evaporation. The different classes of meteorites also show that the degree of depletion in their parent bodies (i.e. mostly planetesimals) is quite variable, but nevertheless systematic. For primitive and least disturbed carbonaceous chondrites the element depletion pattern is a smooth function of TC. The accessible silicate Earth also shows this general depletion pattern, but in detail it is highly complex and requires differentiation processes that are not solely controlled by TC. If only highly lithophile elements are considered the depletion pattern of the silicate Earth reveals a step function that shows that moderately volatile lithophile elements have abundances that are ca. 0.1 times the chondritic value, irrespective of their TC. This element pattern observed for bulk silicate Earth can be modelled as a mixture of two distinct components: ca. 90% of a strongly reduced planetary body that is depleted in highly volatile elements and ca. 10% of a more volatile element rich and oxidized component. This mixture can account for the apparent Pb- paradox observed in melts derived from the silicate Earth and provides a time constraint for the mixing event, which is ca. 70 My after the beginning of the solar system. This event corresponds to the giant impact that also formed the Moon.

On the Departure from Isothermality of Pluto's Volatile Ice due to Local Insolation and Topography

NASA Astrophysics Data System (ADS)

Trafton, Laurence M.; Stansberry, John A.

2015-11-01

Pluto’s atmosphere is known to be supported by the vapor pressure of ices that are volatile at low temperature, primarily N2 and secondarily CH4 and CO. The atmospheric bulk is regulated by the globally average temperature of the ice, which is determined by a radiative balance between the diurnally average insolation absorbed globally by the volatile ice and the global volatile ice thermal radiation. This bulk is sufficient that Pluto’s atmosphere is close to hydrostatic equilibrium, though this may not remain so as Pluto continues to move towards aphelion. With the weight of the atmosphere currently distributed evenly around the body, the ice temperature is expected to be globally isothermal in absence of topographic variations, due to the transport of latent heat from regions of high insolation to low insolation through sublimation and condensation. Images returned from the New Horizons spacecraft show topographical features, including mountain ranges that extend above 3.5 km, with albedo variations that suggest a topographical dimension or dependence of the volatile ice deposits. In general, the conditions often applied to a volatile atmosphere of hydrostatic equilibrium and vapor-solid phase equilibrium are approximations that may not always both be appropriate. This is particularly the case in the presence of topography when the atmospheric lapse rate differs from the wet adiabat. We present our results of an investigation of the effect of variable insolation and topography on Pluto’s local ice temperature assuming an atmosphere close to hydrostatic equilibrium.

Evaluating Volatility-controlled Isotope Fractionation During Planet Formation: Kinetics versus Equilibrium

NASA Astrophysics Data System (ADS)

Young, E. D.

2017-12-01

Recent advances in our ability to measure stable isotope ratios of light, rock-forming elements, including those for Zn, K, Fe, Si, and Mg, among others, has resulted in an emerging hypothesis that collisions among rocky planetesimals, planetary embryos, and/or proto-planets caused losses of moderately volatile elements (e.g., K) and "common" or moderately refractory elements (e.g., Mg and Si). The primary evidence is in the form of heavy isotope enrichments in rock-forming elements relative to the chondrite groups that are thought to be representative of planetary precursors. Equilibrium volatility-controlled isotope fractionation for planetesimal magma oceans might have occurred for bodies larger than 0.1% of an Earth mass (½ the mass of Pluto) as these bodies had sufficient gravity to overpower the escape velocities of hot gas at 2000K. Both Jean's escape and viscous drag hydrodynamic escape can obviate the escape velocity limit but will fractionate by mass, not by volatility. Equilibrium vapor/melt fractionation is qualitatively consistent with the greater disparity in 29Si/28Si between Earth and chondrites than in 25Mg/24Mg. However, losses of large masses of vapor are required to record the fractionation in the melts. We consider that if Earth was derived from E chondrite-like materials, the bulk composition of the Earth, assuming refractory Ca was retained, requires > 60% loss of Mg. This is a lot of vapor loss for a process relying on at least intermittent equilibrium, although it comports with the isotopic lever-rule requirements. Paradoxically, the alternative of evaporative loss of rock-forming elements requires less total mass loss. For example, the calculated Mg and Si isotopic compositions of residues resulting from evaporation of chondritic melts can fit the Mg and Si isotopic compositions of Earth, Mars, and angrites with varying background pressures and with total mass losses of near 5% or less. These mass losses are closer to, and even lower than, those suggested by Ca concentrations relative to CI chondrite. Equilibrium models achieve greater Si than Mg isotope fractionation by large mass losses while evaporation models produce this effect for small mass losses. Additional constraints involving other isotope systems as well as models for vapor loss can distinguish between the two scenarios.

Difference in volatile composition between the pericarp tissue and inner tissue of tomato (Solanum lycopersicum) fruit

USDA-ARS?s Scientific Manuscript database

Numerous studies have reported the volatile profiles in the whole fruit or pericarp tissue of tomato (Solanum lycopersicum) fruit; however, information is limited on the volatile composition in the inner tissue and its contribution to tomato aroma. For this, the pericarps and inner tissues of “Money...

49 CFR 173.24a - Additional general requirements for non-bulk packagings and packages.

Code of Federal Regulations, 2010 CFR

2010-10-01

... subchapter. (b) Non-bulk packaging filling limits. (1) A single or composite non-bulk packaging may be filled... gross mass marked on the packaging. (3) A single or composite non-bulk packaging which is tested and... marked on the packaging, or 1.2 if not marked. In addition: (i) A single or composite non-bulk packaging...

49 CFR 173.24a - Additional general requirements for non-bulk packagings and packages.

Code of Federal Regulations, 2012 CFR

2012-10-01

... subchapter. (b) Non-bulk packaging filling limits. (1) A single or composite non-bulk packaging may be filled... gross mass marked on the packaging. (3) A single or composite non-bulk packaging which is tested and... marked on the packaging, or 1.2 if not marked. In addition: (i) A single or composite non-bulk packaging...

49 CFR 173.24a - Additional general requirements for non-bulk packagings and packages.

Code of Federal Regulations, 2013 CFR

2013-10-01

... subchapter. (b) Non-bulk packaging filling limits. (1) A single or composite non-bulk packaging may be filled... gross mass marked on the packaging. (3) A single or composite non-bulk packaging which is tested and... marked on the packaging, or 1.2 if not marked. In addition: (i) A single or composite non-bulk packaging...

Model Atmospheres and Transit Spectra for Hot Rocky Planets

NASA Astrophysics Data System (ADS)

Lupu, Roxana

We propose to build a versatile set of self-consistent atmospheric models for hot rocky exoplanets and use them to predict their transit and eclipse spectra. Hot rocky exoplanets will form the majority of small planets in close-in orbits to be discovered by the TESS and Kepler K2 missions, and offer the best opportunity for characterization with current and future instruments. We will use fully non-grey radiative-convective atmospheric structure codes with cloud formation and vertical mixing, combined with a self-consistent treatment of gas chemistry above the magma ocean. Being in equilibrium with the surface, the vaporized rock material can be a good tracer of the bulk composition of the planet. We will derive the atmospheric structure and escape rates considering both volatile-free and volatile bearing compositions, which reflect the diversity of hot rocky planet atmospheres. Our models will inform follow- up observations with JWST and ground-based instruments, aid the interpretation of transit and eclipse spectra, and provide a better understanding of volatile loss in these atmospheres. Such results will help refine our picture of rocky planet formation and evolution. Planets in ultra-short period (USP) orbits are a special class of hot rocky exoplanets. As shown by Kepler, these planets are generally smaller than 2 Earth radii, suggesting that they are likely to be rocky and could have lost their volatiles through photo-evaporation. Being close to their host stars, these planets are ultra-hot, with estimated temperatures of 1000-3000 K. A number of USP planets have been already discovered (e.g. Kepler-78 b, CoRoT-7 b, Kepler-10 b), and this number is expected to grow by confirming additional planet candidates. The characterization of planets on ultra-short orbits is advantageous due to the larger number of observable transits, and the larger transit signal in the case of an evaporating atmosphere. Much advance has been made in understanding and characterizing hot Jupiters in similar transit configurations. For example, Na has been the first species to be detected in an exoplanet atmosphere, by observing the evaporating hotJupiter HD209458b. Understanding the interplay between the magma outgassing and volatile loss will be an important part of this project. Our team has the expertise in the chemistry, radiative transfer, and atmospheric escape modeling at these exotic temperatures. Our recent work has analyzed the emerging atmospheres of terrestrial planets after giant impacts, using a well-established radiativeconvective atmospheric structure code, with an extensive opacity database for all relevant molecules, and the chemistry self-consistently calculated for continental crust and bulk silicate earth compositions. We will expand on this work by considering a wider range of chemical compositions, assessing the importance of clouds and generating cloudy models, and developing dis-equilibrium models by taking into account vertical mixing and photochemistry. Photo-evaporation will be considered in the energy balance between heating, cooling and mass loss. We also have in-house codes to generate high-resolution eclipse spectra and predict transit depths and observable signatures. The development of the atmospheric code, the molecular opacity updates, the atmospheric structure calculations and the high resolution eclipse spectra will be performed by R. Lupu, M. Marley, and R. Freedman at NASA Ames. The atmospheric chemistry grids will be provided by B. Fegley and K. Lodders at Washington University. The transit spectra and observational features will be computed by J. Fortney at UCSC, and the atmospheric escape calculations will be performed by K. Zahnle at NASA Ames. This proposal addresses the following goals of the Exoplanet Research program: explain observations of exoplanetary systems, and understand the chemical and physical processes of exoplanets. Our results will also inform future JWST observations.

Ambient Effects on Basalt and Rhyolite Lavas under Venusian, Subaerial, and Subaqueous Conditions

NASA Technical Reports Server (NTRS)

Bridges, Nathan T.

1997-01-01

Both subaerial and subaqueous environments have been used as analog settings for Venus volcanism. To assess the merits of this, the effects of ambient conditions on the physical properties of lava on Venus, the seafloor, and land on Earth are evaluated. Rhyolites on Venus and on the surface of Earth solidify before basalts do because of their lower eruption temperatures. Rhyolite crust is thinner than basalt crust at times less than about an hour, especially on Venus. At later times, rhyolite crust is thicker because of its lower latent heat relative to basalt. The high pressure on the seafloor and Venus inhibits the exsolution of volatiles in lavas. Vesicularity and bulk density are proportional, so that lavas of the same composition should be more dense on the seafloor and less dense on land. Because viscosity depends partly upon the fraction of unvesiculated water in a melt, basalts with the same initial volatile abundance will be least viscous on the seafloor and most viscous on land. Assuming the same preeruptive H2O contents, molten rhyolites on Venus will have viscosities approx. 10% that of rhyolites on land. Despite lower expected viscosities, under-water flows are more buoyant and should have heights like subaerial and Venusian lavas of the same composition and extrusive history. In cases where the influence of crust is insignificant, a volume of rhyolite will have a higher aspect ratio than the same volume of basalt, no matter what the environment. If flow rheology is dominated by the presence of strong crust, aspect ratios differ little among environments or between compositions. These analyses support a rhyolitic interpretation for the composition of Venusian festooned flows and a basaltic interpretation for the composition of Venusian steep-sided domes. Although ambient effects are significant, extrusion rate and eruption history must also be considered to explain analogous volcanic landforms on Earth and Venus.

Economic manufacturing of bulk metallic glass compositions by microalloying

DOEpatents

Liu, Chain T.

2003-05-13

A method of making a bulk metallic glass composition includes the steps of:a. providing a starting material suitable for making a bulk metallic glass composition, for example, BAM-11; b. adding at least one impurity-mitigating dopant, for example, Pb, Si, B, Sn, P, to the starting material to form a doped starting material; and c. converting the doped starting material to a bulk metallic glass composition so that the impurity-mitigating dopant reacts with impurities in the starting material to neutralize deleterious effects of the impurities on the formation of the bulk metallic glass composition.

Chemical composition of volatile oils from the pericarps of Indian sandalwood (Santalum album) by different extraction methods.

PubMed

Zhang, Xin Hua; da Silva, Jaime A Teixeira; Jia, Yong Xia; Zhao, Jie Tang; Ma, Guo Hua

2012-01-01

The chemical composition of volatile compounds from pericarp oils of Indian sandalwood, Santalum album L., isolated by hydrodistillation and solvent extraction, were analyzed by GC and GC-MS. The pericarps yielded 2.6 and 5.0% volatile oil by hydrodistillation and n-hexane extraction, and they were colorless and yellow in color, respectively. A total of 66 volatile components were detected. The most prominent compounds were palmitic and oleic acids, representing about 40-70% of the total oil. Many fragrant constituents and biologically active components, such as alpha- and beta-santalol, cedrol, esters, aldehydes, phytosterols, and squalene were present in the pericarp oils. This is the first report of the volatile composition of the pericarps of any Santalum species.

Compositional data for Bengal delta sediment collected from boreholes at Srirampur, Kachua, Bangladesh

USGS Publications Warehouse

Breit, George N.; Yount, James C.; Uddin, Md. Nehal; Muneem, Ad. Atual; Lowers, Heather; Driscoll, Rhonda L.; Whitney, John W.

2006-01-01

Processes active within sediment of the Bengal delta have attracted world concern because of the locally high content of arsenic dissolved in ground water drawn from that sediment. Sediment samples were collected from two boreholes in Srirampur village, Kachua upazila, Chandphur district, Bangladesh, to investigate the processes contributing to arsenic contamination. The samples were mineralogically and chemically analyzed to determine compositional variations related to the arsenic content of the sediment. Mineralogy of the sediments was determined using powder X-ray diffraction. Bulk chemical composition was measured by Combustion, Inductively Coupled Plasma Atomic Emission Spectroscopy, Energy Dispersive X-ray Fluorescence, and Hydride Generation Atomic Absorption Spectrophotometry. Solutions produced by four chemical extractions-0.1 molar strontium chloride, 0.5 normal hydrochloric acid, titanium(III)-EDTA, and a solution of hydrogen peroxide and hydrochloric acid-were analyzed to evaluate the chemical reactivity of the sediment with an emphasis on arsenic residence. Acid-volatile sulfide, acid-soluble sulfate, and reducible sulfide were also measured. Sediment sampled at Srirampur is typically unlithified, gray, micaceous, feldspathic, arenaceous silt and sand. Arsenic content of the sediment ranges from <1 to 210 ppm, with the highest contents measured in sediment collected at a depth of 320 meters. Samples with high arsenic contents typically contain high concentrations of sulfur. The greatest amount of arsenic was extracted using the oxidative hydrogen peroxide and hydrochloric acid extraction solution. The extraction results are consistent with the apparent association of arsenic in sulfur in the bulk chemical analyses. Pyrite is typically the most abundant form of sulfur in the sediment and is dissolved by the oxidative extraction.

USArray Imaging of Continental Crust in the Conterminous United States

NASA Astrophysics Data System (ADS)

Ma, Xiaofei; Lowry, Anthony R.

2017-12-01

The thickness and bulk composition of continental crust provide important constraints on the evolution and dynamics of continents. Crustal mineralogy and thickness both may influence gravity anomalies, topographic elevation, and lithospheric strength, but prior to the inception of EarthScope's USArray, seismic measurements of crustal thickness and properties useful for inferring lithology are sparse. Here we improve upon a previously published methodology for joint inversion of Bouguer gravity anomalies and seismic receiver functions by using parameter space stacking of cross correlations of modeled synthetic and observed receiver functions instead of standard H-κ amplitude stacking. The new method is applied to estimation of thickness and bulk seismic velocity ratio, vP/vS, of continental crust in the conterminous United States using USArray and other broadband network data. Crustal thickness variations are reasonably consistent with those found in other studies and show interesting relationships to the history of North American continental formation. Seismic velocity ratios derived in this study are more robust than in other analyses and hint at large-scale variations in composition of continental crust. To interpret the results, we model the pressure-/temperature-dependent thermodynamics of mineral formation for various crustal chemistries, with and without volatile constituents. Our results suggest that hydration lowers bulk crustal vP/vS and density and releases heat in the shallow crust but absorbs heat in the lowermost crust (where plagioclase breaks down to pyroxene and garnet resulting in higher seismic velocity). Hence, vP/vS variations may provide a useful proxy for hydration state in the crust.

Diversity among mandarin varieties and natural sub-groups in aroma volatiles compositions.

PubMed

Goldenberg, Livnat; Yaniv, Yossi; Doron-Faigenboim, Adi; Carmi, Nir; Porat, Ron

2016-01-15

Mandarins constitute a large, diverse and important group within the Citrus family. Here, we analysed the aroma volatiles compositions of 13 mandarin varieties belonging to seven genetically different natural sub-groups that included common mandarin (C. reticulata Blanco), clementine (C. clementina Hort. ex. Tan), satsuma (C. unshiu Marcovitch), Mediterranean mandarin (C. deliciosa Tenore), King mandarin (C. nobilis Loureiro), and mandarin hybrids, such as tangor (C. reticulata × C. sinensis) and tangelo (C. reticulata × C. paradisi). We found that mandarin varieties among tangors ('Temple', 'Ortanique'), tangelos ('Orlando', 'Minneola') and King ('King') had more volatiles, at higher levels, and were richer in sesquiterpene and ester volatiles, than other varieties belonging to the sub-groups common mandarin ('Ora', 'Ponkan'), clementine ('Oroval', 'Caffin'), satsuma ('Okitsu', 'Owari') and Mediterranean mandarin ('Avana', 'Yusuf Efendi'). Hierarchical clustering and principal component analysis accurately differentiated between mandarin varieties and natural sub-groups according to their aroma-volatile profiles. Although we found wide differences in aroma-volatiles compositions among varieties belonging to different natural sub-groups, we detected only minor differences among varieties within any natural sub-group. These findings suggest that selecting appropriate parents would enable manipulation of aroma-volatile compositions in future mandarin breeding programmes. © 2015 Society of Chemical Industry.

Concentrations of Volatiles in the Lunar Regolith

NASA Technical Reports Server (NTRS)

Taylor, Jeff; Taylor, Larry; Duke, Mike

2007-01-01

To set lower and upper limits on the overall amounts and types of volatiles released during heating of polar regolith, we examined the data for equatorial lunar regolith and for the compositions of comets. The purpose, specifically, was to answer these questions: 1. Upper/Lower limits and 'best guess' for total amount of volatiles (by weight %) released from lunar regolith up to 150C 2. Upper/Lower limit and 'best guess' for composition of the volatiles released from the lunar regolith by weight %

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bonamici, Chloë E.; Kinman, William S.; Fournelle, John H.

Reprocessed earth material is a glassy nuclear fallout debris from near-surface nuclear tests. A geochemical approach to analysis of glassy fallout is uniquely suited to determine the means of reprocessing and shed light on the mechanisms of fallout formation. An improved understanding of fallout formation is of interest both for its potential to guide post-detonation nuclear forensic investigations and in the context of possible affinities between glassy debris and other glasses generated by high-energy natural events, such as meteorite impacts and lightning strikes. Our study presents a large major-element compositional dataset for glasses within aerodynamic fallout from the Trinity nuclearmore » test (“trinitite”) and a geochemically based analysis of the glass compositional trends. Silica-rich and alkali-rich trinitite glasses show compositions and textures consistent with formation through melting of individual mineral grains—quartz and alkali feldspar, respectively—from the test-site sediment. Furthermore, the volumetrically dominant glass phase—called the CaMgFe glass—shows extreme major-element compositional variability. Compositional trends in the CaMgFe glass are most consistent with formation through volatility-controlled condensation from compositionally heterogeneous plasma. Radioactivity occurs only in CaMgFe glass, indicating that co-condensation of evaporated bulk ground material and trace device material was the main mechanism of radioisotope incorporation into trinitite. CaMgFe trinitite glasses overlap compositionally with basalts, rhyolites, fulgurites, tektites, and microtektites but display greater compositional diversity than all of these naturally formed glasses. Indeed, the most refractory CaMgFe glasses compositionally resemble early solar system condensates—specifically, CAIs.« less

Clouds Composition in Super-Earth Atmospheres: Chemical Equilibrium Calculations

NASA Astrophysics Data System (ADS)

Kempton, Eliza M.-R.; Mbarek, Rostom

2015-12-01

Attempts to determine the composition of super-Earth atmospheres have so far been plagued by the presence of clouds. Yet the theoretical framework to understand these clouds is still in its infancy. For the super-Earth archetype GJ 1214b, KCl, Na2S, and ZnS have been proposed as condensates that would form under the condition of chemical equilibrium, if the planet’s atmosphere has a bulk composition near solar. Condensation chemistry calculations have not been presented for a wider range of atmospheric bulk composition that is to be expected for super-Earth exoplanets. Here we provide a theoretical context for the formation of super-Earth clouds in atmospheres of varied composition by determining which condensates are likely to form, under the assumption of chemical equilibrium. We model super-Earth atmospheres assuming they are formed by degassing of volatiles from a solid planetary core of chondritic material. Given the atomic makeup of these atmospheres, we minimize the global Gibbs free energy of over 550 gases and condensates to obtain the molecular composition of the atmospheres over a temperature range of 350-3,000 K. Clouds should form along the temperature-pressure boundaries where the condensed species appear in our calculations. The super-Earth atmospheres that we study range from highly reducing to oxidizing and have carbon to oxygen (C:O) ratios that are both sub-solar and super-solar, thereby spanning a diverse range of atmospheric composition that is appropriate for low-mass exoplanets. Some condensates appear across all of our models. However, the majority of condensed species appear only over specific ranges of H:O and C:O ratios. We find that for GJ 1214b, KCl is the primary cloud-forming condensate at solar composition, in agreement with previous work. However, for oxidizing atmospheres, where H:O is less than unity, K2SO4 clouds form instead. For carbon-rich atmospheres with super-solar C:O ratios, graphite clouds additionally appear. At higher temperatures, clouds are formed from a variety of materials including metals, metal oxides, and aluminosilicates.

76 FR 41086 - Approval and Promulgation of Air Quality Implementation Plans; Ohio; Volatile Organic Compound...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-13

... Promulgation of Air Quality Implementation Plans; Ohio; Volatile Organic Compound Reinforced Plastic Composites... compound (VOC) emissions from reinforced plastic composites production operations. This rule applies to any facility that has reinforced plastic composites production operations. This rule is approvable because it...

Effect of Vertical Shoot-Positioned, Scott-Henry, Geneva Double-Curtain, Arch-Cane, and Parral Training Systems on the Volatile Composition of Albariño Wines.

PubMed

Vilanova, Mar; Genisheva, Zlatina; Tubio, Miguel; Álvarez, Katia; Lissarrague, Jose Ramón; Oliveira, José Maria

2017-09-08

Viticultural practices influence both grape and wine quality. The influence of training systems on volatile composition was investigated for Albariño wine from Rías Baixas AOC in Northwest Spain. The odoriferous contribution of the compounds to the wine aroma was also studied. Volatile compounds belonging to ten groups (alcohols, C₆-compounds, ethyl esters, acetates, terpenols, C 13 -norisoprenoids, volatile phenols, volatile fatty acids, lactones and carbonyl compounds) were determined in Albariño wines from different training systems, Vertical Shoot-Positioned (VSP), Scott-Henry (SH), Geneva Double-Curtain (GDC), Arch-Cane (AC), and Parral (P) during 2010 and 2011 vintages. Wines from GDC showed the highest total volatile composition with the highest concentrations of alcohols, ethyl esters, fatty acids, and lactones families. However, the highest levels of terpenes and C 13 -norisoprenoids were quantified in the SH system. A fruitier aroma was observed in Albariño wines from GDC when odor activity values were calculated.

'Fortified' wines volatile composition: Effect of different postharvest dehydration conditions of wine grapes cv. Malvasia moscata (Vitis vinifera L.).

PubMed

Urcan, Delia Elena; Giacosa, Simone; Torchio, Fabrizio; Río Segade, Susana; Raimondi, Stefano; Bertolino, Marta; Gerbi, Vincenzo; Pop, Nastasia; Rolle, Luca

2017-03-15

The impact of postharvest dehydration on the volatile composition of Malvasia moscata grapes and fortified wines produced from them was assessed. The ripeness effect of fresh grapes on volatile compounds of dehydrated grapes was evaluated for the first time in this study. Fresh grape berries were densimetrically sorted, and more represented density classes were selected. Dehydration of riper berries (20.5 °Brix) led to volatile profiles richer in terpenes, particularly linalool and geraniol. The effect of dehydration rate on the volatile composition of dehydrated grapes and fortified wines was also evaluated. Fast dehydration grapes were richer in total free terpenes, and the resulting wines contained greater amounts of volatile compounds. The predominant compounds were free esters, but linalool, rose oxide, citronellol and geraniol can also contribute to wine aroma, particularly for fast dehydration. β-Damascenone can be an active odorant, although its contribution was greater in wines made from slow dehydrated grapes. Copyright © 2016 Elsevier Ltd. All rights reserved.

Bulk chemical compositions of Antarctic meteorites in the NIPR collection

NASA Astrophysics Data System (ADS)

Kimura, M.; Imae, N.; Yamaguchi, A.; Haramura, H.; Kojima, H.

2018-03-01

Bulk chemical compositions of meteorites were traditionally analyzed by wet chemical analysis, and NIPR has data for 1162 meteorites as of September 2017. We discuss the classification of meteorites on the basis of these data. Chondrite data are distributed in an anomalously wide range of compositions on the Urey-Craig diagram. One of the reasons for such wide distribution is terrestrial weathering producing Fe2O3-bearing phases from Fe-Ni metal and sulfides. Another important factor affecting the bulk compositional data is brecciation. Our observations indicate that many brecciated chondrites contain anomalously abundant opaque minerals, or are depleted in them, resulting in unusual compositions. In case of enstatite and some carbonaceous chondrites, the bulk compositions are distributed in wider ranges than reported before. The bulk compositions of HED meteorites are consistent with their mineralogy and classification. Our study suggests that wet chemical data are still significant for the meteorite classification. However, petrographic observation is indispensable for evaluating the bulk chemistry and classification of meteorites.

Advances in fruit aroma volatile research.

PubMed

El Hadi, Muna Ahmed Mohamed; Zhang, Feng-Jie; Wu, Fei-Fei; Zhou, Chun-Hua; Tao, Jun

2013-07-11

Fruits produce a range of volatile compounds that make up their characteristic aromas and contribute to their flavor. Fruit volatile compounds are mainly comprised of esters, alcohols, aldehydes, ketones, lactones, terpenoids and apocarotenoids. Many factors affect volatile composition, including the genetic makeup, degree of maturity, environmental conditions, postharvest handling and storage. There are several pathways involved in volatile biosynthesis starting from lipids, amino acids, terpenoids and carotenoids. Once the basic skeletons are produced via these pathways, the diversity of volatiles is achieved via additional modification reactions such as acylation, methylation, oxidation/reduction and cyclic ring closure. In this paper, we review the composition of fruit aroma, the characteristic aroma compounds of several representative fruits, the factors affecting aroma volatile, and the biosynthetic pathways of volatile aroma compounds. We anticipate that this review would provide some critical information for profound research on fruit aroma components and their manipulation during development and storage.

Resolving the potential mantle reservoirs that influence volcanism in the West Antarctic Rift System

NASA Astrophysics Data System (ADS)

Maletic, E. L.; Darrah, T.

2017-12-01

Lithospheric extension and magmatism are key characteristics of active continental rift zones and are often associated with long-lasting alkaline magmatic provinces. In these settings, a relationship between lithospheric extension and mantle plumes is often assumed for the forces leading to rift evolution and the existence of a plume is commonly inferred, but typically only extension is supported by geological evidence. A prime example of long-lasting magmatism associated with an extensive area of continental rifting is the West Antarctic Rift System (WARS), a 2000 km long zone of ongoing extension within the Antarctic plate. The WARS consists of high alkaline silica-undersaturated igneous rocks with enrichments in light rare earth elements (LREEs). The majority of previous geochemical work on WARS volcanism has focused on bulk classification, modal mineralogy, major element composition, trace element chemistry, and radiogenic isotopes (e.g., Sr, Nd, and Pb isotopes), but very few studies have evaluated volatile composition of volcanics from this region. Previous explanations for WARS volcanism have hypothesized a plume beneath Marie Byrd Land, decompression melting of a fossilized plume head, decompression melting of a stratified mantle source, and mixing of recycled oceanic crust with one or more enriched mantle sources from the deep mantle, though researchers are yet to reach a consensus. Unlike trace elements and radiogenic isotopes which can be recycled between the crust and mantle and which are commonly controlled by degrees of partial melting and prior melt differentiation, noble gases are present in low concentrations and chemically inert, allowing them to serve as reliable tracers of volatile sources and subsurface processes. Here, we present preliminary noble gas isotope (e.g., 3He/4He, CO2/3He, CH4/3He, 40Ar/36Ar, 40Ar*/4He) data for a suite of lava samples from across the WARS. By coupling major and trace element chemistry with noble gas elemental and isotopic composition and other volatiles from a suite of volcanic rocks in the WARS, we can better constrain a magmatic source and provide geological evidence that could support or oppose the existence of a mantle plume, HIMU plume, or deconvolve mantle-lithosphere interactions.

A Thermodynamic Approach for Modeling H2O-CO2 Solubility in Alkali-rich Mafic Magmas at Mid-crustal Pressures

NASA Astrophysics Data System (ADS)

Allison, C. M.; Roggensack, K.; Clarke, A. B.

2017-12-01

Volatile solubility in magmas is dependent on several factors, including composition and pressure. Mafic (basaltic) magmas with high concentrations of alkali elements (Na and K) are capable of dissolving larger quantities of H2O and CO2 than low-alkali basalt. The exsolution of abundant gases dissolved in alkali-rich mafic magmas can contribute to large explosive eruptions. Existing volatile solubility models for alkali-rich mafic magmas are well calibrated below 200 MPa, but at greater pressures the experimental data is sparse. To allow for accurate interpretation of mafic magmatic systems at higher pressures, we conducted a set of mixed H2O-CO2 volatile solubility experiments between 400 and 600 MPa at 1200 °C in six mafic compositions with variable alkali contents. Compositions include magmas from volcanoes in Italy, Antarctica, and Arizona. Results from our experiments indicate that existing volatile solubility models for alkali-rich mafic magmas, if extrapolated beyond their calibrated range, over-predict CO2 solubility at mid-crustal pressures. Physically, these results suggest that volatile exsolution can occur at deeper levels than what can be resolved from the lower-pressure experimental data. Existing thermodynamic models used to calculate volatile solubility at different pressures require two experimentally derived parameters. These parameters represent the partial molar volume of the condensed volatile species in the melt and its equilibrium constant, both calculated at a standard temperature and pressure. We derived these parameters for each studied composition and the corresponding thermodynamic model shows good agreement with the CO2 solubility data of the experiments. A general alkali basalt solubility model was also constructed by establishing a relationship between magma composition and the thermodynamic parameters. We utilize cation fractions from our six compositions along with four compositions from the experimental literature in a linear regression to generate this compositional relationship. Our revised general model provides a new framework to interpret volcanic data, yielding greater depths for melt inclusion entrapment than previously calculated using other models, and it can be applied to mafic magma compositions for which no experimental data is available.

Influence of accretion on lead in the Earth

NASA Astrophysics Data System (ADS)

Galer, Stephen J. G.; Goldstein, Steven L.

The Pb abundance and isotope composition of the Earth is fundamentally altered from bulk solar system values by the processes occurring during accretion. The most important of the possible processes are volatile element loss and core formation, or some form of inhomogeneous accretion/condensation. The final result is an Earth highly impoverished in 204Pb and other Pb isotopes in primordial abundance. Depending on the exact timing, some radiogenic Pb is also lost either to space or to the core; the degree of loss occurs in the same order as the parent decay constants, namely 207Pb > 206Pb > 208Pb. In this contribution, we explore the likely effects accretion had on the Pb isotope composition of the present day bulk silicate Earth and its secular isotope evolution. This is used to address a number of questions: (1) What can be learned about accretion from the Pb isotope composition of the bulk silicate Earth? (2) Can effects of accretion reconcile the classical "Pb paradox" of a 206Pb-rich bulk silicate Earth? (3) What exactly is the meaning of the "age of the Earth" within the context of Pb isotopes? By consideration of a number of accretion scenarios it is demonstrated that Pb isotopes yield information only on the following two coupled quantities: Firstly, the accretion interval Δ T, the time between initial condensation of the solar nebula (at 4.566Ga) and when accretion-produced U/Pb fractionation (whether loss of Pb to the core or to space) in the silicate Earth ceased. Secondly, the mean 238U/204 Pb ratio μ during accretion—no details of changes in μ during the accretion interval can be resolved. The effects of accretion are thus adequately considered in terms of a simple two-stage model described by μ over ΔT followed by a postaccretion μ. The systematics of μ and ΔT are then examined for the cases of present day terrestrial reservoirs and Archean leads. These estimates of μ and ΔT for the present and past silicate Earth are not compatible with ΔT = 0; rather, they require ΔT ≥ 50Ma and μ ≥ 0 in all instances, with our best estimate of ΔT being 80±40Ma. From a number of lines of argument it can be demonstrated that the U-Pb "age of the Earth" records an endogenous process actively taking place during accretion. Further, this process cannot be volatile loss of Pb, but rather it actually records the termination of Pb partitioning into the core. This does not necessarily date the endpoint of growth of the Earth for two reasons: Firstly, this core formation "age" may itself in part reflect that occurring on bodies later contributing to the Earth; secondly, later infall of bodies may alter μ but leave the U-Pb "age" of the silicate Earth effectively unaltered. Overall, the Earth can be considerably `younger' than previous single-stage model U-Pb ages for the silicate Earth have suggested. In addition, the "lead paradox" is seen to be a natural consequence of the finite time taken for accretion and core formation on the Earth.

Evaluation of Radiopacity of Bulk-fill Flowable Composites Using Digital Radiography.

PubMed

Tarcin, B; Gumru, B; Peker, S; Ovecoglu, H S

2016-01-01

New flowable composites that may be bulk-filled in layers up to 4 mm are indicated as a base beneath posterior composite restorations. Sufficient radiopacity is one of the several important requirements such materials should meet. The aim of this study was to evaluate the radiopacity of bulk-fill flowable composites and to provide a comparison with conventional flowable composites using digital imaging. Ten standard specimens (5 mm in diameter, 1 mm in thickness) were prepared from each of four different bulk-fill flowable composites and nine different conventional flowable composites. Radiographs of the specimens were taken together with 1-mm-thick tooth slices and an aluminum step wedge using a digital imaging system. For the radiographic exposures, a storage phosphor plate and a dental x-ray unit at 70 kVp and 8 mA were used. The object-to-focus distance was 30 cm, and the exposure time was 0.2 seconds. The gray values of the materials were measured using the histogram function of the software available with the system, and radiopacity was calculated as the equivalent thickness of aluminum. The data were analyzed statistically (p<0.05). All of the tested bulk-fill flowable composites showed significantly higher radiopacity values in comparison with those of enamel, dentin, and most of the conventional flowable composites (p<0.05). Venus Bulk Fill (Heraeus Kulzer) provided the highest radiopacity value, whereas Arabesk Flow (Voco) showed the lowest. The order of the radiopacity values for the bulk-fill flowable composites was as follows: Venus Bulk Fill (Heraeus Kulzer) ≥ X-tra Base (Voco) > SDR (Dentsply DeTrey) ≥ Filtek Bulk Fill (3M ESPE). To conclude, the bulk-fill flowable restorative materials, which were tested in this study using digital radiography, met the minimum standard of radiopacity specified by the International Standards Organization.

Origin and evolution of planetary atmospheres

NASA Technical Reports Server (NTRS)

Lewis, John S.

1992-01-01

This report concerns several research tasks related to the origin and evolution of planetary atmospheres and the large-scale distribution of volatile elements in the Solar System. These tasks and their present status are as follows: (1) we have conducted an analysis of the volatility and condensation behavior of compounds of iron, aluminum, and phosphorus in the atmosphere of Venus in response to publish interpretations of the Soviet Venera probe XRF experiment data, to investigate the chemistry of volcanic gases, injection of volatiles by cometary and asteroidal impactors, and reactions in the troposphere; (2) we have completed and are now writing up our research on condensation-accretion modeling of the terrestrial planets; (3) we have laid the groundwork for a detailed study of the effects of water transport in the solar nebula on the bulk composition, oxidation state, and volatile content of preplanetary solids; (4) we have completed an extensive laboratory study of cryovolcanic materials in the outer solar system; (5) we have begun to study the impact erosion and shock alteration of the atmosphere of Mars resulting from cometary and asteroidal bombardment; and (6) we have developed a new Monte Carlo model of the cometary and asteroidal bombardment flux on the terrestrial planets, including all relevant chemical and physical processes associated with atmospheric entry and impact, to assess both the hazards posed by this bombardment to life on Earth and the degree of cross-correlation between the various phenomena (NO(x) production, explosive yield, crater production, iridium signature, etc.) that characterize this bombardment. The purpose of these investigations has been to contribute to the developing understanding of both the dynamics of long-term planetary atmosphere evolution and the short-term stability of planetary surface environments.

Factors related to the attraction of flies at a biosolids composting facility (Bariloche, Argentina).

PubMed

Laos, F; Semenas, L; Labud, V

2004-07-26

The composting process is used to treat biosolids from the Wastewater Treatment Plant of Bariloche (NW Patagonia, Argentina). Since 1998, an odourless, innocuous and stable organic amendment has been produced at the Biosolids Composting Plant of Bariloche. However, volatile compounds produced during this process, attract different vectors, mainly insects belonging to the Order Diptera, particularly in summer. To evaluate factors associated with the attraction of Diptera to composting windrows, volatile compounds, wind velocity, ambient and windrow temperatures were measured and their relationships with the taxa of flies found were determined. Sampling was conducted several months on newly formed windrows during 3 weeks of the thermophilic composting period. Composite samples from each windrow were taken on the first day of each sampling week, from November 1999 to March 2000 to analyze volatile compounds using an 'electronic nose'. Windrow and ambient temperatures and wind velocity were recorded on three consecutive days of each week, from January to March 2000; also the capture of flies was performed in this period. A weekly mean value was calculated for each environmental variable. Canonical Correspondence Analysis was employed to determine relationships between taxa of flies and the studied factors. The electronic nose discriminated among odours emitted, differentiating windrows by the bulking agent employed and by week of the thermophilic composting period. Ambient temperatures increased slightly during the sampling weeks; the highest values of wind velocity were registered during the second sampling week while windrow temperatures were sustained approximately 60 degrees C. Canonical Correspondence Analysis showed that attraction of flies to composting windrows was related to minimum and maximum ambient temperatures and volatile compounds for Muscina stabulans, Fannia sp. and Acaliptratae and to wind velocity for Ophyra sp., Sarcophaga sp., Cochliomyia macellaria and Phaenicia sericata. Copyright 2004 Elsevier B.V.

Double-Vacuum-Bag Process for Making Resin-Matrix Composites

NASA Technical Reports Server (NTRS)

Bradford, Larry J.

2007-01-01

A double-vacuum-bag process has been devised as a superior alternative to a single-vacuum-bag process used heretofore in making laminated fiber-reinforced resin-matrix composite-material structural components. This process is applicable to broad classes of high-performance matrix resins including polyimides and phenolics that emit volatile compounds (solvents and volatile by-products of resin-curing chemical reactions) during processing. The superiority of the double-vacuum-bag process lies in enhanced management of the volatile compounds. Proper management of volatiles is necessary for making composite-material components of high quality: if not removed and otherwise properly managed, volatiles can accumulate in interior pockets as resins cure, thereby forming undesired voids in the finished products. The curing cycle for manufacturing a composite laminate containing a reactive resin matrix usually consists of a two-step ramp-and-hold temperature profile and an associated single-step pressure profile as shown in Figure 1. The lower-temperature ramp-and-hold step is known in the art as the B stage. During the B stage, prepregs are heated and volatiles are generated. Because pressure is not applied at this stage, volatiles are free to escape. Pressure is applied during the higher-temperature ramp-and-hold step to consolidate the laminate and impart desired physical properties to the resin matrix. The residual volatile content and fluidity of the resin at the beginning of application of consolidation pressure are determined by the temperature and time parameters of the B stage. Once the consolidation pressure is applied, residual volatiles are locked in. In order to produce a void-free, high-quality laminate, it is necessary to design the curing cycle to obtain the required residual fluidity and the required temperature at the time of application of the consolidation pressure.

The Abundance and Isotopic Composition of Hg in Extraterrestrial Materials

NASA Technical Reports Server (NTRS)

Lauretta, D. S.

2004-01-01

During the past three year grant period we made excellent progress in our study of the abundances and isotopic compositions of Hg and other volatile trace elements in extraterrestrial materials. As part of my startup package I received funds to construct a state-of-the-art experimental facility to study gas-solid reaction kinetics. Much of our effort was spent developing the methodology to measure the abundance and isotopic composition of Hg at ultratrace levels in solid materials. In our first study, the abundance and isotopic composition of Hg was determined in bulk samples of the Murchison (CM) and Allende (CV) carbonaceous chondrites. We have continued our study of mercury in primitive meteorites and expanded the suite of meteorites to include other members of the CM and CV chondrite group as well as CI and CO chondrites. Samples of the CI chondrite Orgueil, the CM chondrites Murray, Nogoya, and Cold Bokkeveld, the CO chondrites Kainsaz, Omans, and Isna, and the CV chondrites Vigarano, Mokoia, and Grosnaja were tested. We have developed a thermal analysis ICP-MS technique and applied it to the study of a suite of thermally labile elements (Zn, As, Se, Cd, In, Sn, Sb, Te, Hg, Au, Tl, Pb, and Bi) in geologic materials as well.

Depth of cure, flexural properties and volumetric shrinkage of low and high viscosity bulk-fill giomers and resin composites.

PubMed

Tsujimoto, Akimasa; Barkmeier, Wayne W; Takamizawa, Toshiki; Latta, Mark A; Miyazaki, Masashi

2017-03-31

The purpose of this study was to investigate the depth of cure, flexural properties and volumetric shrinkage of low and high viscosity bulk-fill giomers and resin composites. Depth of cure and flexural properties were determined according to ISO 4049, and volumetric shrinkage was measured using a dilatometer. The depths of cure of giomers were significantly lower than those of resin composites, regardless of photo polymerization times. No difference in flexural strength and modulus was found among either high or low viscosity bulk fill materials. Volumetric shrinkage of low and high viscosity bulk-fill resin composites was significantly less than low and high viscosity giomers. Depth of cure of both low and high viscosity bulk-fill materials is time dependent. Flexural strength and modulus of high viscosity or low viscosity bulk-fill giomer or resin composite materials are not different for their respective category. Resin composites exhibited less polymerization shrinkage than giomers.

Angrites: A Volatile-rich Variety of Asteroidal Basalt (Except for Alkalis and Gallium!)

NASA Astrophysics Data System (ADS)

Warren, P. H.; Kallemeyn, G. W.

1995-09-01

Angrites are commonly viewed as extremely volatile-depleted, and a related notion is that they formed by differentiation of a very CAI-rich material [e.g., 1]. Partial melting experiments reportedly reproduce the bulk compositions (although not fassaite-rich mineralogy) of angrites with Allende as starting material [2], but highly CAI-rich parent materials are difficult to reconcile with isotopic and REE data [3,4]. Mittlefehldt and Lindstrom [5] inferred from the low Na/Al ratios of angrites that outgassing, and thus primordial magmatism, was more intense on their parent body than on the eucrite parent asteroid. Of seven elements that (a) have been adequately determined in angrites, and (b) are far more volatile (solar-nebula 50% condensation T [6] = 690-430 K) than the alkalis (1000-910 K), four are enriched, and none is significantly depleted, in average angrite compared to average eucrite or low-Ti mare basalt (Figure). Gallium, which is of intermediate volatility (830 K), is depleted to roughly the same extent as Na and K. Results for A881371 [3] are incomplete (Zn, 6 micrograms/g, is near INAA detection limit), but even based only on AdoR and the two LEW angrites, this pattern seems firmly established. Apparent gas cavities in A881371 [7] also suggest that volatiles are far from uniformly depleted. The only elements known to be depleted, as volatiles, by clearly significant factors in angrites versus eucrites or lunar basalts, are alkalis plus gallium. Besides being moderately volatile, a noteworthy characteristic shared among Ga and alkalis (and not shared with elements such as Br, Se, and Zn) is that these elements probably tend to partition into crustal feldspar during gross differentiation of small (low-pressure) bodies. If gallium + alkalis were depleted by a single process starting from "normal" chondritic material, that process would seem to require selective exposure of a feldspar-enriched region (i.e., crust) to extremely high temperature. Igneous crystallization of the angrites occurred when the solar system was still extremely young, and apparently <=2 Ma after the volatile-depletion process [4]. The data of [4] eliminate 26Al as a potential heat source for magmatism. The angrite volatile pattern may be the product of heating by an intense, short-lived heat source that melted and partially vaporized the crust of an asteroid(s) (not necessarily the final angrite asteroid), without much affecting the deep interior(s), which later (through mixing and/or magmatism) replenished the angritic materials in most volatiles, but not alkalis and Ga. Exogenic heating, as in the often-conjectured (but hard to test) hypothesis that a major early heat source was enhanced solar luminosity (as in FU-Orionis cycles), would seem to be required. LEW 87051 and A881371 are rich in compositionally diverse olivine xenocrysts, and A881371 contains a possible FeS xenocryst [7]. These, and the angrites' great siderophile diversity [3], tend to suggest that magmatism and intensely disruptive cratering (with mixing of precursor materials) were contemporaneous. This scenario is admittedly speculative, but the volatile-depletion pattern is difficult to rationalize with any other model. References: [1] Prinz M. and Weisberg M. (1995) Antarct. Meteorites, XX, 207-210. [2] Jurewicz A. et al. (1993) GCA, 57, 2123-2139. [3] Warren P. et al. (1995) Antarct. Meteorites, XX, 261-264. [4] Lugmair G. and Galer S. 1992) GCA, 56, 1673-1694. [5] Mittlefehldt D. and Lindstrom M. (1990) GCA, 54, 3209-3218. [6] Wasson J. (1985) Meteorites. [7] Warren P. and Davis A. (1995) Antarct. Meteorites, XX, 257-260.

The Diversity of Anomalous HEDs: Isotopic Constraints on the Connection of EET 92023, GRA 98098, and Dhofar 700 With Vesta

NASA Technical Reports Server (NTRS)

Sanborn, M. E.; Yin, Q.-Z.; Mittlefehldt, D. W.

2016-01-01

The possibility for multiple parent bodies, instead of a common parent body of Vesta, for eucrites has been suggested based on the variable oxygen isotopic composition observed in some eucrites.. Recently, we added an extra dimension to the discussion based on the (epsilon)54Cr composition of the same eucrites with known (delta)17O to compare with the normal eucrites. The combined (delta)17O and (epsilon)54Cr isotope systematics for Pasamonte, PCA 91007, A-881394, and Ibitira indicate their likely origin from multiple different parent bodies than the normal eucrites. Often the qualifier anomalous is used to identify HEDs with (delta)17O values that deviate significantly (>3(sigma)) from the mean HED (delta)17O. However, variations in eucrites and diogenites also include unique geochemical characteristics such as bulk composition, trace element abundances, or volatile concentrations, in addition to (delta)17O. Here, we investigate three such geochemically anomalous HEDs: Elephant Moraine (EET) 92023, Graves Nunataks (GRA) 98098, and Dhofar 700. In addition, to verify the homogeneity of (epsilon)54Cr observed for normal HEDs thus far, a set of seven eucrites and diogenites considered normal samples were also investigated.

Hydrogen and major element concentrations on 433 Eros: Evidence for an L- or LL-chondrite-like surface composition.

PubMed

Peplowski, Patrick N; Bazell, David; Evans, Larry G; Goldsten, John O; Lawrence, David J; Nittler, Larry R

2015-03-01

A reanalysis of NEAR X-ray/gamma-ray spectrometer (XGRS) data provides robust evidence that the elemental composition of the near-Earth asteroid 433 Eros is consistent with the L and LL ordinary chondrites. These results facilitated the use of the gamma-ray measurements to produce the first in situ measurement of hydrogen concentrations on an asteroid. The measured value, 1100-700+1600 ppm, is consistent with hydrogen concentrations measured in L and LL chondrite meteorite falls. Gamma-ray derived abundances of hydrogen and potassium show no evidence for depletion of volatiles relative to ordinary chondrites, suggesting that the sulfur depletion observed in X-ray data is a surficial effect, consistent with a space-weathering origin. The newfound agreement between the X-ray, gamma-ray, and spectral data suggests that the NEAR landing site, a ponded regolith deposit, has an elemental composition that is indistinguishable from the mean surface. This observation argues against a pond formation process that segregates metals from silicates, and instead suggests that the differences observed in reflectance spectra between the ponds and bulk Eros are due to grain size differences resulting from granular sorting of ponded material.

A Comparative Study of Continental vs. Intraoceanic Arc Mantle Melting: Experimentally Determined Phase Relations of Hydrous, Primitive Melts

NASA Astrophysics Data System (ADS)

Weaver, S.; Johnston, A.; Wallace, P. J.

2009-12-01

It is widely recognized that H2O and other volatiles play a crucial role in mantle melting in subduction zones. This work is a comparative study focused on determining the H2O-undersaturated, near-liquidus phase relations for two primitive subduction related compositions with the goal of determining the P-T-H2O conditions of mantle melting beneath arcs. These samples, JR-28, a calc-alkaline basalt from Volcan Jorullo, Mexico, and ID-16, a tholeiitic basalt from Okmok Volcano, Aleutian Islands, have major element compositions that indicate they are primary, mantle-derived melts. H2O-undersaturated piston cylinder experiments have been carried out at upper mantle pressures and temperatures (1.0-2.0 GPa and 1100-1350°C). The near-liquidus mineralogy of these two compositions has been mapped in P-T- H2O space in order to constrain the conditions under which these melts are multiply saturated with a mantle residue (lherzolite or harzburgite). Previous studies of dissolved volatiles in olivine-hosted melt inclusions have provided an estimate of pre-eruptive H2O-contents for JR-28 at ≥5 wt% H2O and experiments have been carried out accordingly. Preliminary results for JR-28 at 5 wt% H2O show olivine ± Cr-rich spinel on the liquidus at 1.0 GPa and enstatite as the liquidus phase at higher pressures (1.3 to 2.0 GPa). Ca-rich pyroxene appears in only one experiment 50°C below the liquidus at 1.5 GPa. These data show that JR-28 melts are multiply saturated with a harzburgite assemblage at ~1175°C and ~1.2 GPa at 5 wt% H2O. Experiments at 7 wt% H2O show similar results, although the olivine/Cr-spinel stability field expands at the expense of the enstatite stability field. Consequently, the olivine-enstatite cotectic is shifted to higher pressures and slightly cooler temperatures. The relatively high SiO2 content in the bulk rock (~52 wt% SiO2) supports the hypothesis that JR-28 last equilibrated with a depleted or harzburgite residue rather than a more fertile mantle assemblage. In contrast, preliminary results for ID-16 at 5 wt% H2O show olivine stable at 1.0 GPa, and Ca-rich clinopyroxene at higher pressures (1.5 and 2.0 GPa). The presence of Ca-rich pyroxene in these experiments likely reflects the higher bulk CaO content of ID-16 (~10.7 wt% CaO) relative to JR-28 (~8.3 wt% CaO). Therefore, it will be explored if ID-16 melts are in equilibrium with a lherzolite source. Experiments at 3 and 5 wt% H2O will be conducted for ID-16 and comparisons for the two compositions will be presented. A comparative study of this nature will allow us to assess the influence of volatiles on mantle melt generation in both continental margin and intra-oceanic arcs.

CO2 driven weathering vs plume driven weathering as inferred from the groundwater of a persistently degassing basaltic volcano: Mt. Etna

NASA Astrophysics Data System (ADS)

Liotta, Marcello; D'Alessandro, Walter

2016-04-01

At Mt. Etna the presence of a persistent volcanic plume provides large amounts of volcanogenic elements to the bulk deposition along its flanks. The volcanic plume consists of solid particles, acidic droplets and gaseous species. After H2O and CO2, S, Cl and F represent the most abundant volatile elements emitted as gaseous species from the craters. During rain events acidic gases interact rapidly with droplets lowering the pH of rain. This process favors the dissolution and dissociation of the most acidic gases. Under these conditions, the chemical weathering of volcanic rocks and ashes is promoted by the acid rain during its infiltration. Subsequently during groundwater circulation, chemical weathering of volcanic rocks is also driven by the huge amount of deep magmatic carbon dioxide (CO2) coming up through the volcanic edifice and dissolving in the water. These two different weathering steps occur under very different conditions. The former occurs in a highly acidic environment (pH < 4) and the reaction rates depend strongly on the pH, while the latter usually occurs under slightly acidic conditions since the pH has been already neutralized by the interaction with volcanics rocks. The high content of chlorine is mainly derived from interactions between the plume and rainwater, while the total alkalinity can be completely ascribed to the dissociation of carbonic acid (H2CO3) after the hydration of CO2. The relative contributions of plume-derived elements/weathering and CO2-driven weathering has been computed for each element. In addition, the comparison between the chemical compositions of the bulk deposition and of groundwater provides a new understanding about the mobility of volatile elements. Other processes such as ion exchange, iddingsite formation, and carbonate precipitation can also play roles, but only to minor extents. The proposed approach has revealed that the persistent plume strongly affects the chemical composition of groundwater at Mt. Etna and probably also at other volcanoes characterized by huge open-conduit degassing activity.

Partial reactive crystallization of variable CO2-bearing siliceous MORB-eclogite-derived melt in fertile peridotite and genesis of alkalic basalts with signatures of crustal recycling

NASA Astrophysics Data System (ADS)

Mallik, A.; Dasgupta, R.

2013-12-01

The presence of heterogeneity in the form of recycled altered oceanic crust (MORB-eclogite) has been proposed in the source of HIMU ocean island basalts (OIBs) [1]. Partial melts of recycled oceanic crust, however, are siliceous and Mg-poor and thus do not resemble the major element compositions of alkalic OIBs that are silica-poor and Mg-rich. In an upwelling heterogenous mantle, MORB-eclogite undergoes melting deeper than volatile-free peridotite, hence, andesitic partial melt derived from eclogite will react with subsolidus peridotite. We have examined the effect of such a melt-rock reaction under volatile-free conditions at 1375 °C, 3 GPa by varying the melt-rock ratio from 8 to 50 wt.% [2]. We concluded that the reacted melts reproduce certain major element characteristics of oceanic basanites, but not nephelinites. Also, the melt-rock reaction produces olivine and garnet-bearing websteritic residue. Because presence of CO2 has been invoked in the source of many HIMU ocean islands, the effect of CO2 on such a melt-rock reaction needs to be evaluated. Accordingly, we performed reaction experiments on mixtures of 25% and 33% CO2-bearing andesitic partial melt and peridotite at 1375 °C, 3 GPa by varying the dissolved CO2 content of the reacting melts from 1 to 5 wt.% (bulk CO2 from 0.25 to 1.6 wt.%) [3, this study]. Owing to melt-rock reaction, with increasing CO2 in the bulk mixture, (a) modes of olivine and cpx decrease while melt, opx and garnet increase, (b) reacted melts evolve to greater degree of Si-undersaturation (from andesite through basanite to nephelinite), (c) enhanced crystallization of garnet take place with higher CO2 in the melt, reducing alumina content of the reacted melts, and (d) CaO and MgO content of the reacted melts increase, without affecting FeO* and Na2O contents (indicating greater propensity of Ca2+ and Mg2+ over Fe2+ and Na+ to enter silicate melt as carbonate). For a given melt-MgO, the CO2-bearing reacted melts are a better match for alkalic basalts in terms of SiO2, Al2O3, CaO and CaO/Al2O3 than the CO2-free ones [3]. Using the experimental data, we have further developed an empirical model to predict mineral modes in residue and reacted melt compositions for olivine-opx saturated lithologies as a function of melt:rock ratio and bulk CO2 content. For example, in case of 5 wt.% eclogite melt infiltrating in fertile peridotite, with bulk CO2 from 0 to 2 wt.%, the derivative melts show an increase in CaO and MgO from 11 to 16 wt.%, 15 to 24 wt.%, respectively and decrease in SiO2 and Al2O3 from 45 to 39 wt.% and 14 to 5 wt.%, respectively. From this model, we have created a major element composition space of MORB-eclogite-derived reactive melt mass vs. bulk CO2 and we predict that primary HIMU-type magmas require <5 to 10 wt.% of MORB-eclogite melt input and up to 0.8 wt.% bulk CO2 in their source. Our model also allows determining the residual lithology at the source of alkalic basalts, produced owing to eclogite melt-peridotite reaction with or without CO2. [1] Jackson & Dasgupta (2008) EPSL 276, 175-186. [2] Mallik & Dasgupta (2012) EPSL 329-330, 97-108. [3] Mallik & Dasgupta (in press) JPetrol.

Physico-Chemical Evolution of Organic Aerosol from Wildfire Emissions

NASA Astrophysics Data System (ADS)

Croteau, P.; Jathar, S.; Akherati, A.; Galang, A.; Tarun, S.; Onasch, T. B.; Lewane, L.; Herndon, S. C.; Roscioli, J. R.; Yacovitch, T. I.; Fortner, E.; Xu, W.; Daube, C.; Knighton, W. B.; Werden, B.; Wood, E.

2017-12-01

Wildfires are the largest combustion-related source of carbonaceous emissions to the atmosphere; these include direct emissions of black carbon (BC), primary organic aerosol (POA) and semi-volatile, intermediate-volatility, and volatile organic compounds (SVOCs, IVOCs, and VOCs). However, there are large uncertainties surrounding the evolution of these carbonaceous emissions as they are physically and chemically transformed in the atmosphere. To understand these transformations, we performed sixteen experiments using an environmental chamber to simulate day- and night-time chemistry of gas- and aerosol-phase emissions from 6 different fuels at the Fire Laboratory in Missoula, MT. Across the test matrix, the experiments simulated 2 to 8 hours of equivalent day-time aging (with the hydroxyl radical and ozone) or several hours of night-time aging (with the nitrate radical). Aging resulted in an average organic aerosol (OA) mass enhancement of 28% although the full range of OA mass enhancements varied between -10% and 254%. These enhancement findings were consistent with chamber and flow reactor experiments performed at the Fire Laboratory in 2010 and 2012 but, similar to previous studies, offered no evidence to link the OA mass enhancement to fuel type or oxidant exposure. Experiments simulating night-time aging resulted in an average OA mass enhancement of 10% and subsequent day-time aging resulted in a decrease in OA mass of 8%. While small, for the first time, these experiments highlighted the continuous nature of the OA evolution as the wildfire smoke cycled through night- and day-time processes. Ongoing work is focussed on (i) quantifying bulk compositional changes in OA, (ii) comparing the near-field aging simulated in this work with far-field aging simulated during the same campaign (via a mini chamber and flow tube) and (iii) integrating wildfire smoke aging datasets over the past decade to examine the relationship between OA mass enhancement ratios, modified combustion efficiency, initial aerosol concentrations and composition, aerosol size, oxidant exposure, VOC:NOx ratios, and emissions and speciation of SOA precursors.

The Amorphous Composition of Three Mudstone Samples from Gale Crater: Implications for Weathering and Diagenetic Processes on Mars

NASA Technical Reports Server (NTRS)

Achilles, C. N.; Downs, R. T.; Rampe, E. B.; Morris, R. V.; Bristow, T. F.; Ming, D. W.; Blake, D. F.; Vaniman, D. T.; Morrison, S. M.; Sutter, B.;

A temporal record of pre-eruptive magmatic volatile contents at Campi Flegrei: Insights from texturally-constrained apatite analyses

NASA Astrophysics Data System (ADS)

Stock, Michael J.; Isaia, Roberto; Humphreys, Madeleine C. S.; Smith, Victoria C.; Pyle, David M.

2016-04-01

Apatite is capable of incorporating all major magmatic volatile species (H2O, CO2, S, Cl and F) into its crystal structure. Analysis of apatite volatile contents can be related to parental magma compositions through the application of pressure and temperature-dependent exchange reactions (Piccoli and Candela, 1994). Once included within phenocrysts, apatite inclusions are isolated from the melt and preserve a temporal record of magmatic volatile contents in the build-up to eruption. In this work, we measured the volatile compositions of apatite inclusions, apatite microphenocrysts and pyroxene-hosted melt inclusions from the Astroni 1 eruption of Campi Flegrei, Italy (Stock et al. 2016). These data are coupled with magmatic differentiation models (Gualda et al., 2012), experimental volatile solubility data (Webster et al., 2014) and thermodynamic models of apatite compositional variations (Piccoli and Candela, 1994) to decipher pre-eruptive magmatic processes. We find that apatite halogen/OH ratios decreased through magmatic differentiation, while melt inclusion F and Cl concentrations increased. Melt inclusion H2O contents are constant at ~2.5 wt%. These data are best explained by volatile-undersaturated differentiation over most of the crystallisation history of the Astroni 1 melt, with melt inclusion H2O contents reset at shallow levels during ascent. Given the high diffusivity of volatiles in apatite (Brenan, 1993), the preservation of volatile-undersaturated melt compositions in microphenocrysts suggests that saturation was only achieved 10 - 103 days before eruption. We suggest that late-stage transition into a volatile-saturated state caused an increase in magma chamber overpressure, which ultimately triggered the Astroni 1 eruption. This has major implications for monitoring of Campi Flegrei and other similar volcanic systems. Piccoli and Candela, 1994. Am. J. of Sc., 294, 92-135. Stock et al., 2016, Nat. Geosci. Gualda et al., 2012. J. Pet., 53, 875-890. Webster et al., 2014. J. Pet., 55, 2217-2248. Brenan, 1993. Chem. Geol., 110, 195-210.

Rubidium Isotope Composition of the Earth and the Moon: Evidence for the Origin of Volatile Loss During Planetary Accretion

NASA Astrophysics Data System (ADS)

Pringle, E. A.; Moynier, F.

2016-12-01

The Earth-Moon system has a variety of chemical and isotopic characteristics that provide clues to understanding the mechanism of lunar formation. One important observation is the depletion in moderately volatile elements in the Moon compared to the Earth. This volatile element depletion may be a signature of volatile loss during the Moon-forming Giant Impact. Stable isotopes are powerful tracers of such a process, since volatile loss via evaporation enriches the residue in heavy isotopes. However, early studies searching for the fingerprint of volatile loss failed to find any resolvable variations [1]. Recent work has now revealed heavy isotope enrichments in the Moon relative to the Earth for the moderately volatile elements Zn [2,3] and K [4]. The purely lithophile nature of Rb (in contrast to the chalcophile/lithophile nature of Zn) and the higher volatility of Rb compared to K make Rb an ideal element with which to study the origin of lunar volatile element depletion. We have developed a new method for the high-precision measurement of Rb isotope ratios by MC-ICP-MS. The Rb isotope compositions of terrestrial rocks define a narrow range, indicating that Rb isotope fractionation during igneous differentiation is limited (<30 ppm/amu). There is a clear signature of Rb loss during evaporation in volatile-depleted achondrites and lunar rocks. In particular, eucrites are significantly enriched in 87Rb (up to several per mil) relative to chondrites. Similarly, lunar basalts are enriched in 87Rb compared to terrestrial basalts, by 200 ppm for 87Rb/85Rb. These data are the first measurements of a resolvable difference in Rb isotope composition between the Earth and the Moon. The variations in Rb isotope composition between the Earth and the Moon are consistent with Rb isotope fractionation due to evaporation. References: [1] Humayun & Clayton GCA 1995. [2] Paniello et al. Nature 2012. [3] Kato et al. Nat. Comm. 2015. [4] Wang and Jacobsen Nature in press.

A geochemical approach to constraining the formation of glassy fallout debris from nuclear tests

DOE PAGES

Bonamici, Chloë E.; Kinman, William S.; Fournelle, John H.; ...

2016-12-15

Reprocessed earth material is a glassy nuclear fallout debris from near-surface nuclear tests. A geochemical approach to analysis of glassy fallout is uniquely suited to determine the means of reprocessing and shed light on the mechanisms of fallout formation. An improved understanding of fallout formation is of interest both for its potential to guide post-detonation nuclear forensic investigations and in the context of possible affinities between glassy debris and other glasses generated by high-energy natural events, such as meteorite impacts and lightning strikes. Our study presents a large major-element compositional dataset for glasses within aerodynamic fallout from the Trinity nuclearmore » test (“trinitite”) and a geochemically based analysis of the glass compositional trends. Silica-rich and alkali-rich trinitite glasses show compositions and textures consistent with formation through melting of individual mineral grains—quartz and alkali feldspar, respectively—from the test-site sediment. Furthermore, the volumetrically dominant glass phase—called the CaMgFe glass—shows extreme major-element compositional variability. Compositional trends in the CaMgFe glass are most consistent with formation through volatility-controlled condensation from compositionally heterogeneous plasma. Radioactivity occurs only in CaMgFe glass, indicating that co-condensation of evaporated bulk ground material and trace device material was the main mechanism of radioisotope incorporation into trinitite. CaMgFe trinitite glasses overlap compositionally with basalts, rhyolites, fulgurites, tektites, and microtektites but display greater compositional diversity than all of these naturally formed glasses. Indeed, the most refractory CaMgFe glasses compositionally resemble early solar system condensates—specifically, CAIs.« less

A geochemical approach to constraining the formation of glassy fallout debris from nuclear tests

NASA Astrophysics Data System (ADS)

Bonamici, Chloë E.; Kinman, William S.; Fournelle, John H.; Zimmer, Mindy M.; Pollington, Anthony D.; Rector, Kirk D.

2017-01-01

Glassy nuclear fallout debris from near-surface nuclear tests is fundamentally reprocessed earth material. A geochemical approach to analysis of glassy fallout is uniquely suited to determine the means of reprocessing and shed light on the mechanisms of fallout formation. An improved understanding of fallout formation is of interest both for its potential to guide post-detonation nuclear forensic investigations and in the context of possible affinities between glassy debris and other glasses generated by high-energy natural events, such as meteorite impacts and lightning strikes. This study presents a large major-element compositional dataset for glasses within aerodynamic fallout from the Trinity nuclear test ("trinitite") and a geochemically based analysis of the glass compositional trends. Silica-rich and alkali-rich trinitite glasses show compositions and textures consistent with formation through melting of individual mineral grains—quartz and alkali feldspar, respectively—from the test-site sediment. The volumetrically dominant glass phase—called the CaMgFe glass—shows extreme major-element compositional variability. Compositional trends in the CaMgFe glass are most consistent with formation through volatility-controlled condensation from compositionally heterogeneous plasma. Radioactivity occurs only in CaMgFe glass, indicating that co-condensation of evaporated bulk ground material and trace device material was the main mechanism of radioisotope incorporation into trinitite. CaMgFe trinitite glasses overlap compositionally with basalts, rhyolites, fulgurites, tektites, and microtektites but display greater compositional diversity than all of these naturally formed glasses. Indeed, the most refractory CaMgFe glasses compositionally resemble early solar system condensates—specifically, CAIs.

Fatty acid composition and volatile compounds of caviar from farmed white sturgeon (Acipenser transmontanus).

PubMed

Caprino, Fabio; Moretti, Vittorio Maria; Bellagamba, Federica; Turchini, Giovanni Mario; Busetto, Maria Letizia; Giani, Ivan; Paleari, Maria Antonietta; Pazzaglia, Mario

2008-06-09

The present study was conducted to characterize caviar obtained from farmed white sturgeons (Acipenser transmontanus) subjected to different dietary treatments. Twenty caviar samples from fish fed two experimental diets containing different dietary lipid sources have been analysed for chemical composition, fatty acids and flavour volatile compounds. Fatty acid make up of caviar was only minimally influenced by dietary fatty acid composition. Irrespective of dietary treatments, palmitic acid (16:0) and oleic acid (OA, 18:1 n-9) were the most abundant fatty acid followed by docosahexaenoic acid (DHA, 22:6 n-3) and eicopentaenoic (EPA, 20:5 n-3). Thirty-three volatile compounds were isolated using simultaneous distillation-extraction (SDE) and identified by GC-MS. The largest group of volatiles were represented by aldehydes with 20 compounds, representing the 60% of the total volatiles. n-Alkanals, 2-alkenals and 2,4-alkadienals are largely the main responsible for a wide range of flavours in caviar from farmed white surgeon.

Volatile elements in and on lunar volcanic glasses: What do they tell us about lunar genesis?

NASA Technical Reports Server (NTRS)

Koeberl, C.

1984-01-01

There are good reasons to believe that lunar volcanic glasses originated from a deep interior source. The presence of a thin layer of surface correlated elements on these glasses may indicate that the Moon has some reservoirs that are enriched in volatiles. Since the glasses themselves do not show similar enrichment, the source should be of limited extent. Three scenarios are advanced for the origin of these elements. The mechanism for lunar volcanism differs from the mechanism for volcanism on Earth since the former produces bubbling and the latter explosive fountaining. From the condensation behavior of the volatile compounds, which leads to heterogeneous condensation, it is concluded that comparing element ratios of surface correlated elements gives little sense. It seems as if the volatile reservoirs are of rather limited extent and that they do not enlarge the volatile content of the bulk Moon significantly.

Toward measurements of volatile behavior at realistic pressure and temperature conditions in planetary deep interiors. (Invited)

NASA Astrophysics Data System (ADS)

McWilliams, R. S.

2013-12-01

Laboratory studies of volatiles at high pressure are constantly challenged to achieve conditions directly relevant to planets. While dynamic compression experiments are confined to adiabatic pathways that frequently exceed relevant temperatures due to the low densities and bulk moduli of volatile samples, static compression experiments are often complicated by sample reactivity and mobility before reaching relevant temperatures. By combining the speed of dynamic compression with the flexibility of experimental path afforded by static compression, optical spectroscopy measurements in volatiles such as H, N, and Ar have been demonstrated at previously-unexplored planetary temperature (up to 11,000 K) and pressure (up to 150 GPa). These optical data characterize the electronic properties of extreme states and have implications for bonding, transport, and mixing behavior in volatiles within planets. This work was conducted in collaboration with D.A. Dalton and A.F. Goncharov (Carnegie Institution of Washington) and M.F. Mahmood (Howard University).

Degassing-induced crystallization of basaltic magma and effects on lava rheology

USGS Publications Warehouse

Lipman, P.W.; Banks, N.G.; Rhodes, J.M.

1985-01-01

During the north-east rift eruption of Mauna Loa volcano, Hawaii, on 25 March-14 April 1984 (Fig. 1), microphenocryst contents of erupted lava increased from 0.5 to 30% without concurrent change in either bulk magma composition or eruption temperature (1,140 ?? 3 ??C). The crystallization of the microphenocrysts is interpreted here as being due to undercooling of the magma 20-30 ??C below its liquidas; the undercooling probably resulted from separation and release of volatiles as the magma migrated 12 km from the primary summit reservoir to the eruption site on the north-east rift zone. Such crystallization of magma during an eruption has not been documented previously. The undercooling and crystallization increased the effective viscosity of the magma, leading to decreased eruption rates and stagnation of the lava flow. ?? 1985 Nature Publishing Group.

Alterations in the morphological, sugar composition, and volatile flavor properties of petai (Parkia speciosa Hassk.) seed during ripening.

PubMed

Asikin, Yonathan; Kusumiyati; Taira, Eizo; Wada, Koji

2018-04-01

Petai seeds are one of the well-known strong-smelling foods of the Southeast Asian region that have been harvested and commercially offered in different ripening forms. The current study focused on alterations in the size, color, sugar composition, and volatile flavor properties of petai seeds in the four ripening stages (unripe, mid ripe, ripe, and over-ripe). The ripening process was mainly indicated by the increase in size and weight as seed color turned paler and less greenish. The total sugar content gradually increased during ripening, and then elevated from 1.60 g/100 g (ripe seed) to the level of 2.82 g/100 g in the over-ripe seed. Ripening also altered the volatile flavor composition of petai seed, wherein the predominant aldehydes (hexanal and acetaldehyde) were decreased, and the sulfuric compounds (hydrogen sulfide, methanethiol, and 1,2,4-trithiolane) tended to increase. Additionally, gas chromatography-olfactometry (GC-O) analysis revealed alterations in the perceived odor strength and sensation of each volatile compound and demonstrated volatile flavor profiles, viz. detection percentages of volatile group odor strengths and descriptive odors, of petai seed. These results provide valuable information for monitoring alterations in the physical appearance, sugar composition, and aroma that represent the flavor quality in seasonal petai seed. Copyright © 2018 Elsevier Ltd. All rights reserved.

Differences in volatile methyl siloxane (VMS) profiles in biogas from landfills and anaerobic digesters and energetics of VMS transformations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tansel, Berrin, E-mail: tanselb@fiu.edu; Surita, Sharon C.

2014-11-15

Highlights: • In the digester gas, D4 and D5 comprised the 62% and 27% if siloxanes, respectively. • In landfill gas, the bulk of siloxanes were TMSOH (58%) followed by D4 (17%). • Methane utilization may be a possible mechanism for TMSOH formation in the landfills. • The geometric configurations of D4 and D5 molecules make them very stable. - Abstract: The objectives of this study were to compare the types and levels of volatile methyl siloxanes (VMS) present in biogas generated in the anaerobic digesters and landfills, evaluate the energetics of siloxane transformations under anaerobic conditions, compare the conditionsmore » in anaerobic digesters and municipal solid waste (MSW) landfills which result in differences in siloxane compositions. Biogas samples were collected at the South District Wastewater Treatment Plant and South Dade Landfill in Miami, Florida. In the digester gas, D4 and D5 comprised the bulk of total siloxanes (62% and 27%, respectively) whereas in the landfill gas, the bulk of siloxanes were trimethylsilanol (TMSOH) (58%) followed by D4 (17%). Presence of high levels of TMSOH in the landfill gas indicates that methane utilization may be a possible reaction mechanism for TMSOH formation. The free energy change for transformation of D5 and D4 to TMSOH either by hydrogen or methane utilization are thermodynamically favorable. Either hydrogen or methane should be present at relatively high concentrations for TMSOH formation which explains the high levels present in the landfill gas. The high bond energy and bond distance of the Si–O bond, in view of the atomic sizes of Si and O atoms, indicate that Si atoms can provide a barrier, making it difficult to break the Si–O bonds especially for molecules with specific geometric configurations such as D4 and D5 where oxygen atoms are positioned inside the frame formed by the large Si atoms which are surrounded by the methyl groups.« less

Compositional dependent partial molar volume and compressibility of CO2 in rhyolite, phonolite and basalt glasses

NASA Astrophysics Data System (ADS)

Lerch, P.; Seifert, R.; Malfait, W. J.; Sanchez-Valle, C.

2012-12-01

Carbon dioxide is the second most abundant volatile in magmatic systems and plays an important role in many magmatic processes, e.g. partial melting, volatile saturation, outgassing. Despite this relevance, the volumetric properties of carbon-bearing silicates at relevant pressure and temperature conditions remain largely unknown because of considerable experimental difficulties associated with in situ measurements. Density and elasticity measurements on quenched glasses can provide an alternative source of information. For dissolved water, such measurements indicate that the partial molar volume is independent of compositions at ambient pressure [1], but the partial molar compressibility is not [2, 3]. Thus the partial molar volume of water may depend on melt composition at elevated pressure. For dissolved CO2, no such data is available. In order to constrain the effect of magma composition on the partial molar volume and compressibility of dissolved carbon, we determined the density and elasticity for three series of carbon-bearing basalt, phonolite and rhyolite glasses, quenched from 3.5 GPa and relaxed at ambient pressure. The CO2 content varies between 0 to 3.90 wt% depending on the glass composition. Glass densities were determined using the sink/float method in a diiodomethane (CH2I2) - acetone mixture. Brillouin measurements were conducted on relaxed and unrelaxed silicate glasses in platelet geometry to determine the compressional (VP) and shear (VS) wave velocities and elastic moduli. The partial molar volume of CO2 in rhyolite, phonolite and basalt glasses is 25.4 ± 0.9, 22.1 ± 0.6 and 26.6 ±1.8 cm3/mol, respectively. Thus, unlike for dissolved water, the partial molar volume of CO2 displays a resolvable compositional effect. Although the composition and CO2/carbonate speciation of the phonolite glasses is intermediate between that of the rhyolite and basalt glasses, the molar volume is not. Similar to dissolved water, the partial molar bulk modulus of CO2 displays a strong compositional effect. If these compositional dependencies persist in the analogue melts, the partial molar volume of dissolved CO2 will depend on melt composition, both at low and elevated pressure. Thus, for CO2-bearing melts, a full quantitative understanding of density dependent magmatic processes, such as crystal fractionation, magma mixing and melt extraction will require in situ measurements for a range of melt compositions. [1] Richet, P. et al., 2000, Contrib Mineral Petrol, 138, 337-347. [2] Malfait et al. 2011, Am. Mineral. 96, 1402-1409. [3] Whittington et al., 2012, Am. Mineral. 97, 455-467.

The Evolution of the EH4 Chondrite Indarch at High Pressure and Temperature: The First Experimental Results

NASA Technical Reports Server (NTRS)

Berthet, S.; Malavergne, V.; Righter, K.; Corgne, A.; Combes, R.

2006-01-01

Chondrite groups are characterized by variations in bulk composition and oxidation state, illustrating in part heterogeneity in the early solar nebula. Planetary accretion could be explained by at least two different scenarios: the homogeneous [1] and heterogeneous accretion models [2, 3]. In particular, for the formation of the Earth, some studies (e.g. [2, 3]) assume that one component is highly reduced material comparable to enstatite chondrites, devoid of volatile elements but containing all other elements in C1 abundance ratios. To derive constraints on the understanding of early differentiation processes, studies of the silicate phase relations and their interactions with metal, at relevant P-T-fO2, are required. Melting relations and equilibrium partitioning behaviour have been studied on peridotitic and chondritic starting compositions at pressures and temperatures corresponding to the transition zone and lower mantle [4, 5, 6]. However, enstatite chondrites, which are highly reduced primitive meteorites, have not yet been studied experimentally under such conditions. Thus, multianvil experiments have been performed at 20-25 GPa and 2000-2400 C on the EH4 chondrite Indarch.

Bulk, rare earth and other trace elements in Apollo 14 and 15 and Luna 16 samples

NASA Technical Reports Server (NTRS)

Laul, J. C.; Wakita, H.; Showalter, D. L.; Boynton, W. V.; Schmitt, R. A.

1971-01-01

The chemical abundances were measured by instrumental and radiochemical neutron activation analysis in a variety of lunar specimens. Apollo 14 soils are characterized by significant enrichments of Al2O3, Na2O and K2O and depletions of TiO2, FeO, MnO and Cr2O3 relative to Apollo 11 and to most of Apollo 12 soils. The uniform abundances in 14230 core tube soils and three other Apollo 14 soils indicate that the regolith is uniform to at least 22 cm depth and within approximately 200 m from the lunar module. Two Luna 16 breccias are similar in composition to Luna 16 soils. Four Apollo 15 soils (LM, STA 4, 9, and 9a) have variable compositions. Interelement correlations between MnO-FeO, Sc-FeO, V-Cr2O3 and K2O-Hf negate the hypothesis that howardite achondrites may be primitive lunar matter, argue against the fission hypothesis for the origin of the moon, and precludes any selective large scale volatilization of alkalies during lunar magmatic events.

Chlorine in Lunar Basalts

NASA Technical Reports Server (NTRS)

Barnes, J. J.; Anand, M.; Franchi, I. A.

2017-01-01

In the context of the lunar magma ocean (LMO) model, it is anticipated that chlorine (and other volatiles) should have been concentrated in the late-stage LMO residual melts (i.e., the dregs enriched in incompatible elements such as K, REEs, and P, collectively called KREEP, and in its primitive form - urKREEP, [1]), given its incompatibility in mafic minerals like olivine and pyroxene, which were the dominant phases that crystallized early in the cumulate pile of the LMO (e.g., [2]). When compared to chondritic meteorites and terrestrial rocks (e.g., [3-4]), lunar samples often display heavy chlorine isotope compositions [5-9]. Boyce et al. [8] found a correlation between delta Cl-37 (sub Ap) and bulk-rock incompatible trace elements (ITEs) in lunar basalts, and used this to propose that early degassing of Cl (likely as metal chlorides) from the LMO led to progressive enrichment in remaining LMO melt in Cl-37over Cl-35- the early degassing model. Barnes et al. [9] suggested that relatively late degassing of chlorine from urKREEP (to yield delta Cl-37 (sub urKREEP greater than +25 per mille) followed by variable mixing between KREEPy melts and mantle cumulates (characterized by delta Cl-370 per mille) could explain the majority of Cl isotope data from igneous lunar samples. In order to better understand the processes involved in giving rise to the heavy chlorine isotope compositions of lunar samples, we have performed an in situ study of chlorine isotopes and abundances of volatiles in lunar apatite from a diverse suite of lunar basalts spanning a range of geochemical types.

76 FR 4835 - Approval and Promulgation of Air Quality Implementation Plans; Ohio; Volatile Organic Compound...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-01-27

... Promulgation of Air Quality Implementation Plans; Ohio; Volatile Organic Compound Reinforced Plastics...) emissions from reinforced plastic composites production operations to Ohio's State Implementation plan (SIP). This rule applies to any facility that has reinforced plastic composites production operations. This...

Sources of volatiles in basalts from the Galapagos Archipelago: deep and shallow evidence

NASA Astrophysics Data System (ADS)

Peterson, M. E.; Saal, A. E.; Hauri, E. H.; Werner, R.; Hauff, S. F.; Kurz, M. D.; Geist, D.; Harpp, K. S.

2010-12-01

The study of volatiles (H2O, CO2, F, S, and Cl) is important because volatiles assert a strong influence on mantle melting and magma crystallization, as well as on the viscosity and rheology of the mantle. Despite this importance, there have been a minimal number of volatile studies done on magmas from the four main mantle sources that define the end member compositions of the Galapagos lavas. For this reason, we here present new volatile concentrations of 89 submarine glass chips from dredges collected across the archipelago during the SONNE SO158, PLUM02, AHA-NEMO, and DRIFT04 cruises. All samples, with the exception of six, were collected at depths greater than 1000m. Major elements (E-probe), and volatile and trace elements (SIMS), are analyzed on the same glass chip, using 4 chips per sample, to better represent natural and analytical variation. Trace element contents reveal three main compositional groups: an enriched group typical of OIB, a group with intermediate compositions, and a group with a depleted trace element composition similar to MORB. The absolute ranges of volatile contents for all three compositional groups are .098-1.15wt% for H2O, 10.7-193.7 ppm for CO2, 61.4-806.5 ppm for F, 715.8-1599.2 ppm for S and 3.8-493.3 for Cl. The effect of degassing, sulfide saturation and assimilation of hydrothermally altered material must be understood before using the volatile content of submarine glasses to establish the primary volatile concentration of basalts and their mantle sources. CO2 has a low solubility in basaltic melts causing it to extensively degas. Based on the CO2/Nb ratio, we estimate the extent of degassing for the Galapagos lavas to range from approximately undegassed to 90% degassed. We demonstrate that 98% of the samples are sulfur undersaturated. Therefore, sulfur will behave as a moderately incompatible element during magmatic processes. Finally, we evaluate the effect of assimilation of hydrothermally altered material on the volatile content of the lavas. This process is evident when volatile/refractory element ratios are compared to the trace elements indicative of interaction between melt and the oceanic lithosphere such as a positive Sr anomaly (Sr*) in a primitive mantle normalized diagram. This is indicative of the interaction of basaltic melts with plagioclase cumulates. For the Galapagos depleted submarine glasses, we find a positive correlation between Sr* and all volatile/refractory element ratios suggesting significant volatile input from melt-lithosphere interaction. These samples, due to their low trace element concentrations, readily show the alteration signature, thus making the establishment of their primitive volatile content difficult. As a result, we will present the primary volatile concentrations for the trace element intermediate and enriched groups after careful consideration for degassing, sulfide saturation, and assimilation of hydrothermally altered material.

Asthenospheric kimberlites: Volatile contents and bulk compositions at 7 GPa

NASA Astrophysics Data System (ADS)

Stamm, Natalia; Schmidt, Max W.

2017-09-01

During ascent, kimberlites react with the lithospheric mantle, entrain and assimilate xenolithic material, loose volatiles and suffer from syn- and post-magmatic alteration. Consequently, kimberlite rocks deviate heavily from their primary melt. Experiments at 7 GPa, 1300-1480 °C, 10-30 wt% CO2 and 0.46 wt% H2O on a proposed primitive composition from the Jericho kimberlite show that saturation with a lherzolitic mineral assemblage occurs only at 1300-1350 °C for a carbonatitic melt with <8 wt% SiO2 and >35 wt% CO2. At asthenospheric temperatures of >1400 °C, where the Jericho melt stays kimberlitic, this composition saturates only in low-Ca pyroxene, garnet and partly olivine. We hence forced the primitive Jericho kimberlite into multiple saturation with a lherzolitic assemblage by adding a compound peridotite. Saturation in olivine, low- and high-Ca pyroxene and garnet was obtained at 1400-1650 °C (7 GPa), melts are kimberlitic with 18-29 wt% SiO2 + Al2O3, 22.1-24.6 wt% MgO, 15-27 wt% CO2 and 0.4-7.1 wt% H2O; with a trade-off of H2O vs. CO2 and temperature. Melts in equilibrium with high-Ca pyroxene with typical mantle compositions have ≥2.5 wt% Na2O, much higher than the commonly proposed 0.1-0.2 wt%. The experiments allow for a model of kimberlite origin in the convective upper mantle, which only requires mantle upwelling that causes melting at the depth where elemental carbon (in metal, diamond or carbide) converts to CO2 (at ∼250 km). If primary melts leading to kimberlites contain a few wt% H2O, then adiabatic temperatures of 1400-1500 °C would yield asthenospheric mantle melts that are kimberlitic (>18 wt% SiO2 + Al2O3) but not carbonatitic (<10 wt% SiO2 + Al2O3) in composition, carbonatites only forming 100-200 °C below the adiabat. These kimberlites represent small melt fractions concentrating CO2 and H2O and then acquire part of their chemical signature by assimilation/fractionation during ascent in the subcratonic lithosphere.

Wintertime aerosol chemical composition, volatility, and spatial variability in the greater London area

NASA Astrophysics Data System (ADS)

Xu, L.; Williams, L. R.; Young, D. E.; Allan, J. D.; Coe, H.; Massoli, P.; Fortner, E.; Chhabra, P.; Herndon, S.; Brooks, W. A.; Jayne, J. T.; Worsnop, D. R.; Aiken, A. C.; Liu, S.; Gorkowski, K.; Dubey, M. K.; Fleming, Z. L.; Visser, S.; Prévôt, A. S. H.; Ng, N. L.

2016-02-01

The composition of PM1 (particulate matter with diameter less than 1 µm) in the greater London area was characterized during the Clean Air for London (ClearfLo) project in winter 2012. Two high-resolution time-of-flight aerosol mass spectrometers (HR-ToF-AMS) were deployed at a rural site (Detling, Kent) and an urban site (North Kensington, London). The simultaneous and high-temporal resolution measurements at the two sites provide a unique opportunity to investigate the spatial distribution of PM1. We find that the organic aerosol (OA) concentration is comparable between the rural and urban sites, but the contribution from different sources is distinctly different between the two sites. The concentration of solid fuel OA at the urban site is about twice as high as at the rural site, due to elevated domestic heating in the urban area. While the concentrations of oxygenated OA (OOA) are well-correlated between the two sites, the OOA concentration at the rural site is almost twice that of the urban site. At the rural site, more than 70 % of the carbon in OOA is estimated to be non-fossil, which suggests that OOA is likely related to aged biomass burning considering the small amount of biogenic SOA in winter. Thus, it is possible that the biomass burning OA contributes a larger fraction of ambient OA in wintertime than what previous field studies have suggested. A suite of instruments was deployed downstream of a thermal denuder (TD) to investigate the volatility of PM1 species at the rural Detling site. After heating at 250 °C in the TD, 40 % of the residual mass is OA, indicating the presence of non-volatile organics in the aerosol. Although the OA associated with refractory black carbon (rBC; measured by a soot-particle aerosol mass spectrometer) only accounts for < 10 % of the total OA (measured by a HR-ToF-AMS) at 250 °C, the two measurements are well-correlated, suggesting that the non-volatile organics have similar sources or have undergone similar chemical processing as rBC in the atmosphere. Although the atomic O : C ratio of OOA is substantially larger than that of solid fuel OA and hydrocarbon-like OA, these three factors have similar volatility, which is inferred from the change in mass concentration after heating at 120 °C. Finally, we discuss the relationship between the mass fraction remaining (MFR) of OA after heating in the TD and atomic O : C of OA and find that particles with a wide range of O : C could have similar MFR after heating. This analysis emphasizes the importance of understanding the distribution of volatility and O : C in bulk OA.

Late Veneer collisions and their impact on the evolution of Venus (PS Division Outstanding ECS Award Lecture)

NASA Astrophysics Data System (ADS)

Gillmann, Cedric; Golabek, Gregor; Tackley, Paul; Raymond, Sean

2017-04-01

During the end of the accretion, the so-called Late Veneer phase, while the bulk of the mass of terrestrial planets is already in place, a substantial number of large collisions can still occur. Those impacts are thought to be responsible for the repartition of the Highly Siderophile Elements. They are also susceptible to have a strong effect on volatile repartition and mantle convection. We study how Late Veneer impacts modify the evolution of Venus and its atmosphere, using a coupled numerical simulation. We focus on volatile exchanges and their effects on surface conditions. Mantle dynamics, volcanism and degassing processes lead to an input of gases in the atmosphere and are modeled using the StagYY mantle convection code. Volatile losses are estimated through atmospheric escape modeling. It involves two different aspects: hydrodynamic escape (0-500 Myr) and non-thermal escape. Hydrodynamic escape is massive but occurs only when the solar energy input is strong. Post 4 Ga escape from non-thermal processes is comparatively low but long-lived. The resulting state of the atmosphere is used to the calculate greenhouse effect and surface temperature, through a one-dimensional gray radiative-convective model. Large impacts are capable of contributing to (i) atmospheric escape, (ii) volatile replenishment and (iii) energy transfer to the mantle. We test various impactor compositions, impact parameters (velocity, location, size, and timing) and eroding power. Scenarios we tested are adapted from numerical stochastic simulations (Raymond et al., 2013). Impactor sizes are dominated by large bodies (R>500 km). Erosion of the atmosphere by a few large impacts appears limited. Swarms of smaller more mass-effective impactors seem required for this effect to be significant. Large impactors have two main effects on the atmosphere. They can (i) create a large input of volatile from the melting they cause during the impact and through the volatiles they carry. This leads to an increase in atmosphere density and surface temperatures. However, early impacts can also (ii) deplete the mantle of Venus and (assuming strong early escape) ultimately remove volatiles from the system, leading to lower late degassing and lower surface temperatures. The competition between those effects depends on the time of the impact, which directly governs the strength of atmospheric losses.

Chemical composition of the semi-volatile grains of comet 67P/Churyumov-Gerasimenko

NASA Astrophysics Data System (ADS)

Wurz, Peter; Altwegg, Kathrin; Balsiger, Hans; Berthelier, Jean-Jacques; Bieler, André; Calmonte, Ursina; De Keyser, Johan; Fiethe, Björn; Fuselier, Stefan; Gasc, Sébastien; Gombosi, Tamas; Jäckel, Annette; Korth, Axel; Le Roy, Lena; Mall, Urs; Rème, Henri; Rubin, Martin; Tzou, Chia-Yu

2017-04-01

The European Space Agency's Rosetta spacecraft (Glassmeier et al., 2007) has been in orbit of the comet 67P/Churyumov-Gerasimenko (67P/C-G) since August 2014. On board is the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) instrument suite (Balsiger et al., 2007). ROSINA consists of two mass spectrometers, the Double Focusing Mass Spectrometer (DFMS) and the Reflectron-type Time-Of-Flight (RTOF) (Scherer et al., 2006), as well as the COmet Pressure Sensor (COPS). ROSINA is designed to detect and monitor the neutral gas and thermal plasma environment in the comet's coma by in situ investigation. The two mass spectrometers have high dynamic ranges and complement each other with high mass resolution (DFMS) and high time resolution and large mass range (RTOF). Especially the unprecedented sensitivity and mass resolution of DFMS together with the large mass range of RTOF allow determining precisely light species (e.g. isotopologues) as well as detecting heavy organic species. The pressure sensor COPS measures total gas densities, bulk velocities, and gas temperatures. ROSINA has been collecting data on the composition of the coma and activity of the comet from 3.5 AU to pericentre and out again to 3.5 AU. The Rosetta mission presents a unique opportunity to directly sample the parent species in the thin cometary atmosphere of a Kuiper-belt object at distances in excess of 2.5 AU from the Sun all the way to the pericentre of the cometary orbit at 1.24 AU. The ROSINA experiment continuously measured the chemical composition of the gases in the cometary coma. Occasionally, a dust grain of cometary origin enters the ion source of a ROSINA instrument where the volatile part evaporates since these ion sources are hot. We will report on the first measurements of the volatile inventory of such dust grains. Volatile release from cometary dust grains was observed with all three ROSINA instruments on several occasions. Because the volatile content of such a dust grain is completely evaporated in such an ion source after a few 100 seconds, the RTOF instrument is best suited for the investigation of its chemical composition since several complete mass spectra are recorded during this time. The rate of dust grains recorded in RTOF is small, and we report on the collection and analysis of 9 dust grains during the October 2014 to July 2016 time period. It is estimated that these grains contain about 1E-15 g of volatiles, which would correspond to a grain of the order of 100 nm in size if made up of volatiles alone. We fitted the recorded mass spectra of RTOF with a set of 61 molecules, and their molecular fragments resulting from the ionisation. The major groups of chemical species are hydrocarbons, oxygenated hydrocarbons, nitrogen-bearing molecules, sulphur-bearing molecules, halogenated molecules and others (including water and CO2). About 70% of these grains are depleted in water compared to the comet coma, thus, can be considered as semi-volatile dust grains, and the other about 30% are water grains. The mineral phase of these grains, if there is any, cannot be investigated in these measurements. However, in an earlier investigation the bulk composition of mineral grains on the surface of the comet was inferred from solar wind sputtering of these grains (Wurz et al., 2015). H. Balsiger, K. Altwegg, P. Bochsler, P. Eberhardt, J. Fischer, S. Graf, A. Jäckel, E. Kopp, U. Langer, M. Mildner, J. Müller, T. Riesen, M. Rubin, S. Scherer, P. Wurz, S. Wüthrich, E. Arijs, S. Delanoye, J. De Keyser, E. Neefs, D. Nevejans, H. Rème, C. Aoustin, C. Mazelle, J.-L. Médale, J.A. Sauvaud, J.-J. Berthelier, J.-L. Ber-taux, L. Duvet, J.-M. Illiano, S.A. Fuselier, A.G. Ghielmetti, T. Magoncelli, E.G. Shelley, A. Korth, K. Heerlein, H. Lauche, S. Livi, A. Loose, U. Mall, B. Wilken, F. Gliem, B. Fiethe, T.I. Gombosi, B. Block, G.R. Carignan, L.A. Fisk, J.H. Waite, D.T. Young, and H. Wollnik, ROSINA - Rosetta Orbiter Spectrometer for Ion and Neutral Analysis, Space Science Review 128 (2007), 745-801. K.-H Glassmeier, H. Boehnhardt, D. Koschny, E. Kührt, and I. Richter, The Rosetta Mission: Flying To-wards the Origin of the Solar System, Space Science Reviews 128 (2007), 1-21. S. Scherer, K. Altwegg, H. Balsiger, J. Fischer, A. Jäckel, A. Korth, M. Mildner, D. Piazza, H. Rème, and P. Wurz, A novel principle for an ion mirror design in time-of-flight mass spectrometry, Int. Jou. Mass Spectr. 251 (2006) 73-81. P. Wurz, M. Rubin, K. Altwegg, H. Balsiger, S. Gasc, A. Galli, A. Jäckel, L. Le Roy, U. Calmonte, C. Tzou, U.A. Mall, B. Fiethe, J. De Keyser, J.J. Berthelier, H. Rème, A. Bieler, V. Tenishev, T.I. Gombosi, and S.A. Fuselier, Solar Wind Sputtering of Dust on the Surface of 67P/Churyumov-Gerasimenko, Astron. Astrophys. 583, A22 (2015) 1-9, DOI: 10.1051/0004-6361/201525980.

High-density volatiles in the system C-O-H-N for the calibration of a laser Raman microprobe

USGS Publications Warehouse

Chou, I.-Ming; Pasteris, J.D.; Seitz, J.C.

1990-01-01

Three methods have been used to produce high-density volatiles in the system C-O-H-N for the calibration of a laser Raman microprobe (LRM): synthetic fluid-inclusion, sealed fused-quartz-tube, and high-pressure-cell methods. Because quantitative interpretation of a Raman spectrum of mixed-volatile fluid inclusions requires accurate knowledge of pressure- and composition-sensitive Raman scattering efficiencies or quantification factors for each species, calibrations of these parameters for mixtures of volatiles of known composition and pressure are necessary. Two advantages of the synthetic fluid-inclusion method are that the inclusions can be used readily in complementary microthermometry (MT) studies and that they have sizes and optical properties like those in natural samples. Some disadvantages are that producing H2O-free volatile mixtures is difficult, the composition may vary from one inclusion to another, the exact composition and density of the inclusions are difficult to obtain, and the experimental procedures are complicated. The primary advantage of the method using sealed fused-quartz tubes is its simplicity. Some disadvantages are that exact compositions for complex volatile mixtures are difficult to predict, densities can be approximated only, and complementary MT studies on the tubes are difficult to conduct. The advantages of the high-pressure-cell method are that specific, known compositions of volatile mixtures can be produced and that their pressures can be varied easily and are monitored during calibration. Some disadvantages are that complementary MT analysis is impossible, and the setup is bulky. Among the three methods for the calibration of an LRM, the high-pressure-cell method is the most reliable and convenient for control of composition and total pressure. We have used the high-pressure cell to obtain preliminary data on 1. (1) the ratio of the Raman quantification factors for CH4 and N2 in an equimolar CH4N2 mixture and 2. (2) the spectral peak position of ??1 of CH4 in that mixture, as well as in pure CH4, at pressures up to 690 bars. These data were successfully applied to natural inclusions from the Duluth Complex in order to derive their compositions and total pressures. ?? 1990.

A POLYMER-CERAMIC COMPOSITE MEMBRANE FOR RECOVERING VOLATILE ORGANIC COMPOUNDS FROM WASTEWATERS BY PERVAPORATION

EPA Science Inventory

A composite membrane was constructed on a porous ceramic support from a block copolymer of styrene and butadiene (SBS). It was tested in a laboratory pervaporation apparatus for recovering volatile organic compounds (VOCs) such a 1,1,1-trichloroethane (TCA) and trichloroethylene ...

Heterogeneous pumice populations in the 2.08-Ma Cerro Galán Ignimbrite: Implications for magma recharge and ascent preceding a large-volume silicic eruption

USGS Publications Warehouse

Wright, Heather M.; Folkes, Christopher B.; Cas, Ray A.F.; Cashman, Katharine V.

2011-01-01

Triggering mechanisms of large silicic eruptions remain a critical unsolved problem. We address this question for the ~2.08-Ma caldera-forming eruption of Cerro Galán volcano, Argentina, which produced distinct pumice populations of two colors: grey (5%) and white (95%) that we believe may hold clues to the onset of eruptive activity. We demonstrate that the color variations correspond to both textural and compositional variations between the clast types. Both pumice types have bulk compositions of high-K, high-silica dacite to low-silica rhyolite, but there are sufficient compositional differences (e.g., ~150 ppm lower Ba at equivalent SiO2 content and 0.03 wt.% higher TiO2 in white pumice than grey) to suggest that the two pumice populations are not related by simple fractionation. Trace element concentrations in crystals mimic bulk variations between clast types, with grey pumice containing elevated Ba, Cu, Pb, and Zn concentrations in both bulk samples (average Cu, Pb, and Zn concentrations are 27, 35, and 82 in grey pumice vs. 11, 19, and 60 in white pumice) and biotite phenocrysts and white pumice showing elevated Li concentrations in biotite and plagioclase phenocrysts. White and grey clasts are also texturally distinct: White pumice clasts contain abundant phenocrysts (44–57%), lack microlites, and have highly evolved groundmass glass compositions (76.4–79.6 wt.% SiO2), whereas grey pumice clasts contain a lower percentage of phenocrysts/microphenocrysts (35–49%), have abundant microlites, and have less evolved groundmass glass compositions (69.4–73.8 wt.% SiO2). There is also evidence for crystal transfer between magma producing white and grey pumice. Thin highly evolved melt rims surround some fragmental crystals in grey pumice clasts and appear to have come from magma that produced white pumice. Furthermore, based on crystal compositions, white bands within banded pumice contain crystals originating in grey magma. Finally, only grey pumice clasts form breadcrusted surface textures. We interpret these compositional and textural variations to indicate distinct magma batches, where grey pumice originated from an originally deeper, more volatile-rich dacite recharge magma that ascended through and mingled with the volumetrically dominant, more highly crystalline chamber that produced white pumice. Shortly before eruption, the grey pumice magma stalled within shallow fractures, forming a vanguard magma phase whose ascent may have provided a trigger for eruption of the highly crystalline rhyodacite magma. We suggest that in the case of the Cerro Galán eruption, grey pumice provides evidence not only for cryptic silicic recharge in a large caldera system but also a probable trigger for the eruption.

Heterogeneous pumice populations in the 2.08-Ma Cerro Galán Ignimbrite: implications for magma recharge and ascent preceding a large-volume silicic eruption

NASA Astrophysics Data System (ADS)

Wright, Heather M. N.; Folkes, Chris B.; Cas, Raymond A. F.; Cashman, Katharine V.

2011-12-01

Triggering mechanisms of large silicic eruptions remain a critical unsolved problem. We address this question for the ~2.08-Ma caldera-forming eruption of Cerro Galán volcano, Argentina, which produced distinct pumice populations of two colors: grey (5%) and white (95%) that we believe may hold clues to the onset of eruptive activity. We demonstrate that the color variations correspond to both textural and compositional variations between the clast types. Both pumice types have bulk compositions of high-K, high-silica dacite to low-silica rhyolite, but there are sufficient compositional differences (e.g., ~150 ppm lower Ba at equivalent SiO2 content and 0.03 wt.% higher TiO2 in white pumice than grey) to suggest that the two pumice populations are not related by simple fractionation. Trace element concentrations in crystals mimic bulk variations between clast types, with grey pumice containing elevated Ba, Cu, Pb, and Zn concentrations in both bulk samples (average Cu, Pb, and Zn concentrations are 27, 35, and 82 in grey pumice vs. 11, 19, and 60 in white pumice) and biotite phenocrysts and white pumice showing elevated Li concentrations in biotite and plagioclase phenocrysts. White and grey clasts are also texturally distinct: White pumice clasts contain abundant phenocrysts (44-57%), lack microlites, and have highly evolved groundmass glass compositions (76.4-79.6 wt.% SiO2), whereas grey pumice clasts contain a lower percentage of phenocrysts/microphenocrysts (35-49%), have abundant microlites, and have less evolved groundmass glass compositions (69.4-73.8 wt.% SiO2). There is also evidence for crystal transfer between magma producing white and grey pumice. Thin highly evolved melt rims surround some fragmental crystals in grey pumice clasts and appear to have come from magma that produced white pumice. Furthermore, based on crystal compositions, white bands within banded pumice contain crystals originating in grey magma. Finally, only grey pumice clasts form breadcrusted surface textures. We interpret these compositional and textural variations to indicate distinct magma batches, where grey pumice originated from an originally deeper, more volatile-rich dacite recharge magma that ascended through and mingled with the volumetrically dominant, more highly crystalline chamber that produced white pumice. Shortly before eruption, the grey pumice magma stalled within shallow fractures, forming a vanguard magma phase whose ascent may have provided a trigger for eruption of the highly crystalline rhyodacite magma. We suggest that in the case of the Cerro Galán eruption, grey pumice provides evidence not only for cryptic silicic recharge in a large caldera system but also a probable trigger for the eruption.

A GC-MS study of the volatile organic composition of straw and oyster mushrooms during maturity and its relation to antioxidant activity.

PubMed

Zhang, Zhuo-Min; Wu, Wen-Wei; Li, Gong-Ke

2008-09-01

Mushrooms are very popular in the market for their nutritional and medicinal use. Mushroom volatiles are not only an important factor in the flavor, but also contain many antioxidant compounds. Antioxidant activity is a very important property for disease prevention. The volatile compositional characteristics of straw mushrooms (Volvariella volvacea [Bull. ex Fr.] Sing.) and oyster mushrooms (Pleurotus ostreatus [Jacq. ex Fr.] Kummer) during maturity and the mushroom antioxidant activity related to the non-volatiles and volatiles are studied by a chromatographic method in combination with a spectrophotometric method. The volatile compounds of straw and oyster mushrooms are sampled and identified by a combination sampling method, including headspace solid phase microextraction and steam distillation, followed by gas chromatography-mass spectrometry detection. Among all the volatile compounds identified, 1-octen-3-ol and 3-octanone are the two main compounds with the highest amounts in the volatile compositions of straw and oyster mushrooms. During maturity time of the straw mushrooms, the unsaturated 1-octen-3-ol peak area is reduced, whereas the saturated 3-octanone peak area is increased. However, during normal maturity time of oyster mushrooms, the peak areas of 1-octen-3-ol and 3-octanone remain at the same level. 1-Octen-3-ol has a different antioxidant activity from 3-octanone. Combining the results of antioxidant experiments of water extract and main volatile components by the use of a phosphomolybdenum spectrophotometric method, the conclusion is drawn that oyster mushrooms might possess stronger antioxidant activities than straw mushrooms.

Condensation and Evaporation of Solar System Materials

NASA Astrophysics Data System (ADS)

Davis, A. M.; Richter, F. M.

2003-12-01

It is widely believed that the materials making up the solar system were derived from a nebular gas and dust cloud that went through an early high-temperature stage during which virtually all of the material was in the gas phase. At one time, it was thought that the entire inner solar nebula was hot, but it is now believed that most material was processed through regions where high temperatures were achieved. Certainly some material, such as presolar grains (cf., Mendybaev et al., 2002a), has never been exposed to high temperatures. As the system cooled, solids and perhaps liquids began to condense, but at some point the partially condensed materials became isolated from the remaining gas. Various lines of evidence support this view. At the largest scale, there is the observation that the Earth, Moon, Mars, and all chondritic meteorites except for the CI chondrites are depleted to varying degrees in the abundances of moderately volatile elements relative to bulk solar system composition. The CI chondrites reflect the bulk composition of the solar system for all but hydrogen, carbon, nitrogen, oxygen, and the rare gases, the most volatile elements (see Chapter 1.03; Palme et al., 1988; McDonough and Sun, 1995; Humayun and Cassen, 2000). The depletions in moderately volatile elements are, to a significant degree, correlated with condensation temperature, suggesting progressive removal of gas as condensation proceeded ( Cassen, 1996). Additional observations that can be explained by partial condensation are that various particularly primitive components of meteorites (e.g., calcium-, aluminum-rich refractory inclusions, and certain metal grains) have mineralogy and/or details of their chemical composition that are remarkably similar to what is calculated for equilibrium condensates from a solar composition gas. For example, the calcium-, aluminum-rich inclusions (CAIs) in chondritic meteorites have compositions very similar to that calculated for the first 5% of total condensable matter (see Chapter 1.08; Grossman, 1973; Wänke et al., 1974; Grossman and Ganapathy, 1976; Grossman et al., 1977), where CI chondrites are taken to represent total condensable matter.Elemental abundance patterns ordered by volatility certainly could have been produced by partial condensation, but they could also have been caused by partial evaporation. The relative importance of these opposite processes is still subject to debate and uncertainty. It should be remembered that condensation calculations typically assume chemical equilibrium in a closed system, in which case the system has no memory of the path by which it arrived at a given state, and thus the chemical and isotopic composition of the condensed phase cannot be used to distinguish between partial condensation and partial evaporation. Humayun and Clayton (1995) have taken a somewhat different view by arguing that condensation and evaporation are distinguishable, in that evaporation, but not condensation, will produce isotopically fractionated residues. With this idea in mind, they carefully measured the potassium isotopic compositions of a broad range of solar system materials with different degrees of potassium depletion and found them to be indistinguishable. This they took as evidence that evaporation could not have been a significant process in determining the diverse elemental abundance patterns of the various solar system materials they measured, because had evaporation been important in fractionating potassium it would have also fractionated the potassium isotopes. We will qualify this line of reasoning by arguing that evaporation and condensation can under certain conditions produce isotopically fractionated condensed phases (i.e., that partial evaporation can produce isotopically heavy residues and that partial condensation can produce isotopically light condensates) but that under other conditions both can produce elemental fractionations without significant isotopic fractionation. The absence of isotopic fractionation in a volatile element-depleted condensed phase is more a measure of the degree to which the system maintained thermodynamic equilibrium than a diagnostic of whether the path involved condensation or evaporation.The pervasive volatile element depletion of inner solar system planets and the asteroidal parent bodies of most meteorites is a major, but by no means the only reason to consider evaporation and condensation processes in the early history of the solar system. Chondrules appear to have been rapidly heated and then cooled over a period of minutes to hours (see Chapter 1.07). If this occurred in a gas of solar composition under nonequilibrium conditions, chondrules should have partially evaporated and an isotopic fractionation record should remain. The absence of such effects can be used to chonstrain the conditions of chondrule formation (e.g., Alexander et al., 2000; Alexander and Wang, 2001). There is good petrologic, chemical, and isotopic evidence suggesting that certain solar system materials such as the coarse-grained CAIs are likely evaporation residues. For example, the type B CAIs are often found to have correlated enrichments in the heavy isotopes of silicon and magnesium ( Figure 1), and these isotopic fractionations are very much like those of evaporation residues produced in laboratory experiments. Condensation also appears to be a major control of elemental zoning patterns in metal grains in CH chondrites (Meibom et al., 1999, 2001; Campbell et al., 2001; Petaev et al., 2001; Campbell et al., 2002). A more contemporary example is the isotopic and chemical compositions of deep-sea spherules that have been significantly affected by evaporative loss during atmospheric entry ( Davis et al., 1991a; Davis and Brownlee, 1993; Herzog et al., 1994, 1999; Xue et al., 1995; Alexander et al., 2002). (7K)Figure 1. Isotopic mass fractionation effects in CAIs. Most coarse-grained CAIs have enrichments of a few ‰ amu-1 in magnesium and silicon, whereas "fractionation and unknown nuclear" (FUN) CAIs are isotopically heavier. The volatile element depletion patterns of planetary size objects and the chemical and isotopic composition of numerous smaller objects such as chondrules and CAIs provide the motivation to consider evaporation and condensation process in the early solar system. The key point is that the processes that led to chondrules and planets appear to have occurred under conditions very close to equilibrium, whereas the processes that led to CAIs involved significant departures from equilibrium.

Local deformation fields and marginal integrity of sculptable bulk-fill, low-shrinkage and conventional composites.

PubMed

Miletic, Vesna; Peric, Dejan; Milosevic, Milos; Manojlovic, Dragica; Mitrovic, Nenad

2016-11-01

To compare strain and displacement of sculptable bulk-fill, low-shrinkage and conventional composites as well as dye penetration along the dentin-restoration interface. Modified Class II cavities (N=5/group) were filled with sculptable bulk-fill (Filtek Bulk Fill Posterior, 3M ESPE; Tetric EvoCeram Bulk Fill, Ivoclar Vivadent; fiber-reinforced EverX Posterior, GC; giomer Beautifil Bulk, Schofu), low-shrinkage (Kalore, GC), nanohybrid (Tetric EvoCeram, Ivoclar Vivadent) or microhybrid (Filtek Z250, 3M ESPE) composites. Strain and displacement were determined using the 3D digital image correlation method based on two cameras with 1μm displacement sensitivity and 1600×1200 pixel resolution (Aramis, GOM). Microleakage along dentin axial and gingival cavity walls was measured under a stereomicroscope using a different set of teeth (N=8/group). Data were analyzed using analyses of variance with Tukey's post-test, Pearson correlation and paired t-test (α=0.05). Strain of TEC Bulk, Filtek Bulk, Beautifil Bulk and Kalore was in the range of 1-1.5%. EverX and control composites showed 1.5-2% strain. Axial displacements were between 5μm and 30μm. The least strain was identified at 2mm below the occlusal surface in 4-mm but not in 2-mm layered composites. Greater microleakage occurred along the gingival than axial wall (p<0.05). No correlation was found between strain/displacements and microleakage axially (r 2 =0.082, p=0.821; r 2 =-0.2, p=0.605, respectively) or gingivally (r 2 =-0.126, p=0.729, r 2 =-0.278, p=0.469, respectively). Strain i.e. volumetric shrinkage of sculptable bulk-fill and low-shrinkage composites was comparable to control composites but strain distribution across restoration depth differed. Marginal integrity was more compromised along the gingival than axial dentin wall. Copyright © 2016 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Aerosol volatility in a boreal forest environment

NASA Astrophysics Data System (ADS)

Häkkinen, S. A. K.; ńijälä, M.; Lehtipalo, K.; Junninen, H.; Virkkula, A.; Worsnop, D. R.; Kulmala, M.; Petäjä, T.; Riipinen, I.

2012-04-01

Climate and health effects of atmospheric aerosols are determined by their properties such as their chemical composition. Aerosol chemical composition can be studied indirectly by measuring volatility of aerosol particles. The volatility of submicron aerosol particles (20-500 nm) was studied in a boreal forest site at SMEAR II (Station for Measuring Ecosystem-Atmosphere Relations II) station (Vesala et al., 1998) in Hyytiälä, Finland, during 01/2008-05/2010. The instrument used for the measurements was VDMPS (Volatility Differential Mobility Particle Sizer), which consists of two separate instruments: DMPS (Differential Mobility Particle Sizer, Aalto et al., 2001) and TD (Thermodenuder, Wehner et al., 2002). Aerosol evaporation was examined by heating the aerosol and comparing the total aerosol mass before and after heating. In the VDMPS system ambient aerosol sample was heated up to temperatures ranging from 80 °C to 280 °C. The higher the heating temperature was the more aerosol material was evaporated. There was a non-volatile residual present in aerosol particles when heated up to 280 °C. This residual explained (20±8)% of the total aerosol mass. Aerosol non-volatile mass fraction was highest during winter and smallest during summer months. The role of black carbon in the observed non-volatile residual was determined. Black carbon explained 40 to 90% of the non-volatile mass. Especially during colder seasons noticeable amount of non-volatile material, something else than black carbon, was observed. According to Kalberer et al. (2004) some atmospheric organic species can form polymers that have high evaporation temperatures. Also low-volatile organic salts may contribute to the non-volatile aerosol (Smith et al., 2010). Aerosol mass composition measured directly with AMS (Aerosol Mass Spectrometer, Jayne et al., 2000) was analyzed in order to examine the properties of the non-volatile material (other than black carbon). The AMS measurements were performed during spring and autumn 2008. Results from the aerosol mass spectrometry indicate that the non-volatile residual consists of nitrate and organic compounds, especially during autumn. These compounds may be low-volatile organic nitrates or salts. During winter and spring the non-volatile core (black carbon removed) correlated markedly with carbon monoxide, which is a tracer of anthropogenic emissions. Due to this, the non-volatile residual may also contain other pollutants in addition to black carbon. Thus, it seems that the amount of different compounds in submicron aerosol particles varies with season and as a result the chemical composition of the non-volatile residual changes within a year. This work was supported by University of Helsinki three-year research grant No 490082 and Maj and Tor Nessling Foundation grant No 2010143. Aalto et al., (2001). Physical characterization of aerosol particles during nucleation events. Tellus B, 53, 344-358. Jayne, et al., (2000). Development of an aerosol mass spectrometer for size and composition analysis of submicron particles. Aerosol Sci. Technol., 33(1-2), 49-70. Kalberer et al., (2004). Identification of Polymers as Major Components of Atmospheric Organic Aerosols. Science, 303, 1659-1662. Smith et al., (2010). Observations of aminium salts in atmospheric nanoparticles and possible climatic implications. P. Natl. Acad. Sci., 107(15). Vesala et al., (1998). Long-term field measurements of atmosphere-surface interactions in boreal forest combining forest ecology, micrometeorology, aerosol physics and atmospheric chemistry. Trends Heat, Mass Mom. Trans., 4, 17-35. Wehner et al., (2002). Design and calibration of a thermodenuder with an improved heating unit to measure the size-dependent volatile fraction of aerosol particles. J. Aerosol Sci., 33, 1087-1093.

Laboratory studies of aqueous-phase oxidation of polyols in submicron particles

NASA Astrophysics Data System (ADS)

Daumit, K. E.; Carrasquillo, A. J.; Hunter, J. F.; Kroll, J. H.

2013-12-01

Aqueous-phase oxidation has received recent attention as a potential pathway for the formation of highly oxidized organic aerosol. However most aqueous oxidation studies are performed in bulk solutions rather than aqueous droplets. Here we describe experiments in which aqueous oxidation is carried out within submicron particles, allowing for gas-particle partitioning of reactants, intermediates, and products. Using Fenton chemistry as a source of hydroxyl radicals, and a high-resolution aerosol mass spectrometer (AMS) for online characterization of particle composition, we find that aqueous oxidation can be quite rapid. The formation of high concentrations of oxalic acid is observed in the particle phase with some loss of carbon to the gas phase, indicating the formation of volatile products. We see a rapid degradation of condensed-phase oxidation products upon exposure to ultraviolet lights (centered at 350 nm) suggesting that these products may exist as iron(III)-oxalate complexes. Similar results are also seen when oxidation is carried out in bulk solution (with AMS analysis of the atomized solution); however in some cases the mass loss is less than is observed for submicron particles, likely due to differences in partitioning of early-generation products. Such products can partition out of the aqueous phase at the low liquid water contents in the chamber but remain in solution for further aqueous processing in bulk oxidation experiments. This work suggests that the product distributions from oxidation in aqueous aerosol may be substantially different than those in bulk oxidation, pointing to the need to carry out aqueous oxidation studies under atmospherically relevant partitioning conditions (with liquid water contents mimicking those of cloud droplets or wet aerosol).

Calcination process for radioactive wastes

DOEpatents

Kilian, Douglas C.

1976-05-04

The present invention provides a method for minimizing the volatilization of chlorides during solidification in a fluidized-bed calciner of liquids containing sodium, nitrate and chloride ions. Zirconium and fluoride are introduced into the liquid, and one-half mole of calcium nitrate is added per mole of fluoride present in the liquid mixture. The mixture is calcined in the fluidized-bed calciner at about 500.degree.C., producing a high bulk density calcine product containing the chloride, thus tying up the chloride in the solid product and minimizing chloride volatilization.

Simulating the behavior of volatiles belonging to the C-O-H-S system in silicate melts under magmatic conditions with the software D-Compress

NASA Astrophysics Data System (ADS)

Burgisser, Alain; Alletti, Marina; Scaillet, Bruno

2015-06-01

Modeling magmatic degassing, or how the volatile distribution between gas and melt changes at pressure varies, is a complex task that involves a large number of thermodynamical relationships and that requires dedicated software. This article presents the software D-Compress, which computes the gas and melt volatile composition of five element sets in magmatic systems (O-H, S-O-H, C-S-O-H, C-S-O-H-Fe, and C-O-H). It has been calibrated so as to simulate the volatiles coexisting with three common types of silicate melts (basalt, phonolite, and rhyolite). Operational temperatures depend on melt composition and range from 790 to 1400 °C. A specificity of D-Compress is the calculation of volatile composition as pressure varies along a (de)compression path between atmospheric and 3000 bars. This software was prepared so as to maximize versatility by proposing different sets of input parameters. In particular, whenever new solubility laws on specific melt compositions are available, the model parameters can be easily tuned to run the code on that composition. Parameter gaps were minimized by including sets of chemical species for which calibration data were available over a wide range of pressure, temperature, and melt composition. A brief description of the model rationale is followed by the presentation of the software capabilities. Examples of use are then presented with outputs comparisons between D-Compress and other currently available thermodynamical models. The compiled software and the source code are available as electronic supplementary materials.

Formation of Metal and Silicate Globules in Gujba: A New Bencubbin-like Meteorite Fall

NASA Technical Reports Server (NTRS)

Rubin, Alan E.; Kallemeyn, Gregory W.; Wasson, John T.; Clayton, Robert N.; Mayeda, Toshiko; Grady, Monica; Verchovsky, Alexander B.; Eugster, Otto; Lorenzetti, Silvio

2006-01-01

Gujba is a coarse-grained meteorite fall composed of 41 vol% large kamacite globules, 20 vol% large light-colored silicate globules with cryptocrystalline, barred pyroxene and barred olivine textures, 39 vol% dark-colored, silicate-rich matrix, and rare refractory inclusions. Gujba resembles Bencubbin and Weatherford in texture, oxygen-isotopic composition and in having high bulk delta N-15 values (approximately +685%0). The He-3 cosmic-ray exposure age of Gujba (26 +/- 7 Ma) is essentially identical to that of Bencubbin, suggesting that they were both reduced to meter-size fragments in the same parent-body collision. The Gujba metal globules exhibit metal-troilite quench textures and vary in their abundances of troilite and volatile siderophile elements. We suggest that the metal globules formed as liquid droplets either via condensation in an impact-generated vapor plume or by evaporation of preexisting metal particles in a plume. The lower the abundance of volatile elements in the metal globules, the higher the globule quench temperature. We infer that the large silicate globules also formed from completely molten droplets; their low volatile-element abundances indicate that they also formed at high temperatures, probably by processes analogous to those that formed the metal globules. The coarse-grained Bencubbin-Weatherford-Gujba meteorites may represent a depositional component from the vapor cloud enriched in coarse and dense particles. A second class of Bencubbin-like meteorites (represented by Hammadah a1 Hamra 237 and QUE 94411) may be a finer fraction derived from the same vapor cloud

EVALUATION OF LOW-VOC LATEX PAINTS

EPA Science Inventory

The paper gives results of an evaluation of four commercially available low-VOC (volatile organic compound) latex paints as substitutes for conventional latex paints by assessing both their emission characteristics and their performance as coatings. Bulk analysis indicated that ...

Effects of Methyl Jasmonate on the Composition of Volatile Compounds in Pyropia yezoensis

NASA Astrophysics Data System (ADS)

He, Lihong; Wang, Liang; Wang, Linfang; Shen, Songdong

2018-04-01

Volatile organic compounds in marine algae have been reported to comprise characteristic flavor of algae and play an important role in their growth, development and defensive response. Yet their biogeneration remain largely unknown. Here we studied the composition of volatile compouds in Pyropia yezoensis and their variations in response to methyl jasmonate (MeJA) and diethyldithiocarbamic acid (DIECA) treatment using gas chromatography-mass spectrometry (GC-MS). A total of 44 compounds belonging to the following chemical classes (n) were identified, including aldehydes (11), alcohols (8), acids and esters (6), alkanes (5), ketones (5), alkenes (3), and S- or N-containing miscellaneous compounds (6). External treatment with plant hormone MeJA increased the content of 1-dodecanol, 4-heptenal, and 2-propenoic acid-2-methyl dodecylester, but decreased the content of phytol, 3-heptadecene, 2-pentadecanone, and isophytol. When pretreated with DIECA, an inhibitor of the octadecanoid pathway leading to the biosynthesis of endogeneous jasmonates and some secondary metabolites, phytol and isophytol were increased, while 4-heptenal, 1-dodecanol, and 2-propenoic acid-2-methyl dodecylester were decreased, both of which were negatively correlated with their variations under MeJA treatment. Collectively, these results suggest that MeJA does affect the volatile composition of P. yezoensis, and the octadecanoid pathway together with endogenous jasmonate pathway may be involved in the biosynthesis of volatile compounds, thereby providing some preliminary envision on the composition and biogeneration of volatile compounds in P. yezoensis.

Solar nebula chemistry - Implications for volatiles in the solar system

NASA Technical Reports Server (NTRS)

Fegley, Bruce, Jr.; Prinn, Ronald G.

1989-01-01

Current theoretical models of solar nebula chemistry which take into account the interplay between chemistry and dynamics are presented for the abundant reactive volatile elements including hydrogen, carbon, nitrogen, oxygen, and sulfur. Results of these models indicate that, in the solar nebula, the dominant carbon and nitrogen gases were CO and NO, whereas, in giant planet subnebulae, the dominant carbon and nitrogen gases were CH4 and NH3; in the solar nebula, the Fe metal grains catalyzed the formation of organic compounds from CO and H2 via the Fischer-Tropsch-type reaction. It was also found that, in solar nebula, bulk FeS formation was kinetically favorable, while FeO incorporation into silicates and bulk Fe3O4 formation were kinetically inhibited. Furthermore, clathrate formation was kinetically inhibited in the solar nebula, while it was kinetically favorable in giant planet subnebulae.

Language of plants: Where is the word?

PubMed

Šimpraga, Maja; Takabayashi, Junji; Holopainen, Jarmo K

2016-04-01

Plants emit biogenic volatile organic compounds (BVOCs) causing transcriptomic, metabolomic and behavioral responses in receiver organisms. Volatiles involved in such responses are often called "plant language". Arthropods having sensitive chemoreceptors can recognize language released by plants. Insect herbivores, pollinators and natural enemies respond to composition of volatiles from plants with specialized receptors responding to different types of compounds. In contrast, the mechanism of how plants "hear" volatiles has remained obscured. In a plant-plant communication, several individually emitted compounds are known to prime defense response in receiver plants with a specific manner according to the chemical structure of each volatile compound. Further, composition and ratio of volatile compounds in the plant-released plume is important in plant-insect and plant-plant interactions mediated by plant volatiles. Studies on volatile-mediated plant-plant signaling indicate that the signaling distances are rather short, usually not longer than one meter. Volatile communication from plants to insects such as pollinators could be across distances of hundreds of meters. As many of the herbivore induced VOCs have rather short atmospheric life times, we suggest that in long-distant communications with plant volatiles, reaction products in the original emitted compounds may have additional information value of the distance to emission source together with the original plant-emitted compounds. © 2015 Institute of Botany, Chinese Academy of Sciences.

Phase Equilibria of a S- and C-Poor Lunar Core

NASA Technical Reports Server (NTRS)

Righter, K.; Pando, K.; Go, B. M.; Danielson, L. R.; Habermann, M.

2016-01-01

The composition of the lunar core can have a large impact on its thermal evolution, possible early dynamo creation, and physical state. Geochemical measurements have placed better constraints on the S and C content of the lunar mantle. In this study we have carried out phase equilibrium studies of geochemically plausible S- and C-poor lunar core compositions in the Fe-Ni-S-C system, and apply them to the early history of the Moon. We chose two bulk core compositions, with differing S and C content based on geochemical analyses of S and C trapped melts in Apollo samples, and on the partitioning of S and C between metal and silicate. This approach allowed calculation of core S and C contents - 90% Fe, 9% Ni, 0.5% C, and 0.375% S by weight; a second composition contained 1% each of S and C. Experiments were carried out from 1473K to 1973K and 1 GPa to 5 GPa, in piston cylinder and multi- anvil apparatuses. Combination of the thermal model of with our results, shows that a solid inner core (and therefore initiation of a dynamo) may have been possible in the earliest history of the Moon (approximately 4.2 Ga ago), in agreement with. Thus a volatile poor lunar core may explain the thermal and magnetic history of the Moon.

Effect of layer thickness on the elution of bulk-fill composite components.

PubMed

Rothmund, Lena; Reichl, Franz-Xaver; Hickel, Reinhard; Styllou, Panorea; Styllou, Marianthi; Kehe, Kai; Yang, Yang; Högg, Christof

2017-01-01

An increment layering technique in a thickness of 2mm or less has been the standard to sufficiently convert (co)monomers. Bulk fill resin composites were developed to accelerate the restoration process by enabling up to 4mm thick increments to be cured in a single step. The aim of the present study is to investigate the effect of layer thickness on the elution of components from bulk fill composites. The composites ELS Bulk fill, SDR Bulk fill and Venus Bulkfill were polymerized according to the instruction of the manufacturers. For each composite three groups with four samples each (n=4) were prepared: (1) samples with a layer thickness of 2mm; (2) samples with a layer thickness of 4mm and (3) samples with a layer thickness of 6mm. The samples were eluted in methanol and water for 24h and 7 d. The eluates were analyzed by gas chromatography/mass spectrometry (GC/MS). A total of 11 different elutable substances have been identified from the investigated composites. Following methacrylates showed an increase of elution at a higher layer thickness: TEGDMA (SDR Bulk fill, Venus Bulk fill), EGDMA (Venus Bulk fill). There was no significant difference in the elution of HEMA regarding the layer thickness. The highest concentration of TEGDMA was 146μg/mL for SDR Bulk fill at a layer thickness of 6mm after 7 d in water. The highest HEMA concentration measured at 108μg/mL was detected in the methanol eluate of Venus Bulk fill after 7 d with a layer thickness of 6mm. A layer thickness of 4mm or more can lead to an increased elution of some bulk fill components, compared to the elution at a layer thickness of 2mm. Copyright © 2016 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Triacylglycerols Composition and Volatile Compounds of Virgin Olive Oil from Chemlali Cultivar: Comparison among Different Planting Densities

PubMed Central

Guerfel, Mokhtar; Ben Mansour, Mohamed; Ouni, Youssef; Guido, Flamini; Boujnah, Dalenda; Zarrouk, Mokhtar

2012-01-01

The present study focused on the comparison the chemical composition of virgin olive oil samples obtained from fruits of the main Tunisian olive cultivar (Chemlali) grown in four planting densities (156, 100, 69, and 51 trees ha−1). Despite the variability in the triacylglycerols and volatile compounds composition, the quality indices (free fatty acids, peroxide value, and spectrophotometric indices K232 and K270) all of the virgin olive oils samples studied met the commercial standards. Decanal was the major constituent, accounting for about 30% of the whole volatiles. Moreover, the chemical composition of the volatile fraction of the oil from fruits of trees grown at the planting density of 156, 100, and 51 trees ha−1 was also characterised by the preeminence of 1-hexanol, while oils from fruits of trees grown at the planting density of 69 trees ha−1 had higher content of (E)-2-hexenal (20.3%). Our results confirm that planting density is a crucial parameter that may influence the quality of olive oils. PMID:22629139

Reconstructing mantle volatile contents through the veil of degassing

NASA Astrophysics Data System (ADS)

Tucker, J.; Mukhopadhyay, S.; Gonnermann, H. M.

2014-12-01

The abundance of volatile elements in the mantle reveals critical information about the Earth's origin and evolution such as the chemical constituents that built the Earth and material exchange between the mantle and exosphere. However, due to magmatic degassing, volatile element abundances measured in basalts usually do not represent those in undegassed magmas and hence in the mantle source of the basalts. While estimates of average mantle concentrations of some volatile species can be obtained, such as from the 3He flux into the oceans, volatile element variability within the mantle remains poorly constrained. Here, we use CO2-He-Ne-Ar-Xe measurements in basalts and a new degassing model to reconstruct the initial volatile contents of 8 MORBs from the Mid-Atlantic Ridge and Southwest Indian Ridge that span a wide geochemical range from depleted to enriched MORBs. We first show that equilibrium degassing (e.g. Rayleigh degassing), cannot simultaneously fit the measured CO2-He-Ne-Ar-Xe compositions in MORBs and argue that kinetic fractionation between bubbles and melt lowers the dissolved ratios of light to heavy noble gas species in the melt from that expected at equilibrium. We present a degassing model (after Gonnermann and Mukhopadhyay, 2007) that explicitly accounts for diffusive fractionation between melt and bubbles. The model computes the degassed composition based on an initial volatile composition and a diffusive timescale. To reconstruct the undegassed volatile content of a sample, we find the initial composition and degassing timescale which minimize the misfit between predicted and measured degassed compositions. Initial 3He contents calculated for the 8 MORB samples vary by a factor of ~7. We observe a correlation between initial 3He and CO2 contents, indicating relatively constant CO2/3He ratios despite the geochemical diversity and variable gas content in the basalts. Importantly, the gas-rich popping rock from the North Atlantic, as well as the average mantle ratio computed from the ridge 3He flux and independently estimated CO2 content fall along the same correlation. This observation suggests that undegassed CO2 and noble gas concentrations can be reconstructed in individual samples through measurement of noble gases and CO2 in erupted basalts.

Method of altering the effective bulk density of solid material and the resulting product

DOEpatents

Kool, Lawrence B.; Nolen, Robert L.; Solomon, David E.

1983-01-01

A method of adjustably tailoring the effective bulk density of a solid material in which a mixture comprising the solid material, a film-forming polymer and a volatile solvent are sprayed into a drying chamber such that the solvent evaporates and the polymer dries into hollow shells having the solid material captured within the shell walls. Shell density may be varied as a function of solid/polymer concentration, droplet size and drying temperature.

The volatile oil composition of fresh and air-dried buds of Cannabis sativa.

PubMed

Ross, S A; ElSohly, M A

1996-01-01

The composition of the steam-distilled volatile oil of fresh and air-dried, indoor-grown marijuana was studied by GC/FID and GC/MS. In all, 68 components were detected of which 57 were fully identified. Drying of the plant material had no effect on the qualitative composition of the oil and did not affect the ability of individuals familiar with marijuana smell to recognize the odor.

Sulfur and sulfides in chondrules

NASA Astrophysics Data System (ADS)

Marrocchi, Yves; Libourel, Guy

2013-10-01

The nature and distribution of sulfides within type I PO, POP and PP chondrules of the carbonaceous chondrite Vigarano (CV3) have been studied by secondary electron microscopy and electron microprobe. They occur predominantly as spheroidal blebs composed entirely of low-Ni iron sulfide (troilite, FeS) or troilite + magnetite but in less abundance in association with metallic Fe-Ni beads in opaque assemblages. Troilites are mainly located within the low-Ca pyroxene outer zone and their amounts increase with the abundance of low-Ca pyroxene within chondrules, suggesting co-crystallization of troilite and low-Ca pyroxene during high-temperature events. We show that sulfur concentration and sulfide occurrence in chondrules obey high temperature sulfur solubility and saturation laws. Depending on the fS2 and fO2 of the surrounding gas and on the melt composition, mainly the FeO content, sulfur dissolved in chondrule melts may eventually reach a concentration limit, the sulfur content at sulfide saturation (SCSS), at which an immiscible iron sulfide liquid separates from the silicate melt. The occurrence of both a silicate melt and an immiscible iron sulfide liquid is further supported by the non-wetting behavior of sulfides on silicate phases in chondrules due to the high interfacial tension between their precursor iron-sulfide liquid droplets and the surrounding silicate melt during the high temperature chondrule-forming event. The evolution of chondrule melts from PO to PP towards more silicic compositions, very likely due to high PSiO(g) of the surrounding nebular gas, induces saturation of FeS at much lower S content in PP than in PO chondrules, leading to the co-crystallization of iron sulfides and low-Ca pyroxenes. Conditions of co-saturation of low-Ca pyroxene and FeS are only achieved in non canonical environments characterized by high partial pressures of sulfur and SiO and redox conditions more oxidizing than IW-3. Fe and S mass balance calculations also suggest the occurrence of an external source of iron, very likely gaseous, during chondrule formation. We therefore propose that enrichments in sulfur (and other volatile and moderately volatile elements) from PO to PP type I bulk chondrule compositions towards chondritic values result from progressive reaction between partially depleted olivine-bearing precursors and a volatile-rich gas phase.

The Abundance and Isotopic Composition of Hg in Extraterrestrial Materials

NASA Technical Reports Server (NTRS)

Blum, J. D.; Klaue, Bjorn

2005-01-01

During the three year grant period we made excellent progress in our study of the abundances and isotopic compositions of Hg and other volatile trace elements in extraterrestrial materials. At the time the grant started, our collaborating PI, Dante Lauretts, was a postdoctoral research associate working with Peter Buseck at Arizona State University. The work on chondritic Hg was done in collaboration with Dante Lauretta and Peter Buseck and this study was published in Lauretta et a1 (2001a). In July, 2001 Dante Lauretta accepted a position as an Assistant Professor in the Lunar and Planetary Laboratory at the University of Arizona. His funding was transferred and this grant has supported much of his research activities during his first two years at the U of A. Several other papers are in preparation and will be published soon. We presented papers on this topic at Goldschmidt Conferences, the Lunar and Planetary Science Conferences, and the Annual Meetings of the Meteoritical Society. The work done under this grant has spurred several new directions of inquiry, which we are still pursuing. Included in this paper are the studies of bulk abundances and isotopic compositions of metreoritic Mercury, and the development of a thermal analysis ICP-MS technique applied to thermally liable elements.

Zinc isotope fractionation during magmatic differentiation and the isotopic composition of the bulk Earth

USGS Publications Warehouse

Chen, Heng; Savage, Paul S.; Teng, Fang-Zehn; Helz, Rosalind T.; Moynier, Frédéric

2013-01-01

he zinc stable isotope system has been successfully applied to many and varied fields in geochemistry, but to date it is still not completely clear how this isotope system is affected by igneous processes. In order to evaluate the potential application of Zn isotopes as a proxy for planetary differentiation and volatile history, it is important to constrain the magnitude of Zn isotopic fractionation induced by magmatic differentiation. In this study we present high-precision Zn isotope analyses of two sets of chemically diverse, cogenetic samples from Kilauea Iki lava lake, Hawaii, and Hekla volcano, Iceland, which both show clear evidence of having undergone variable and significant degrees of magmatic differentiation. The Kilauea Iki samples display small but resolvable variations in Zn isotope composition (0.26‰66Zn66Zn defined as the per mille deviation of a sample's 66Zn/64Zn compositional ratio from the JMC-Lyon standard), with the most differentiated lithologies exhibiting more positive δ66Zn values. This fractionation is likely a result of the crystallization of olivine and/or Fe–Ti oxides, which can both host Zn in their crystal structures. Samples from Hekla have a similar range of isotopic variation (0.22‰66Zn66Zn=0.28±0.05‰ (2s.d.).

The Origin of the Moon Within a Terrestrial Synestia

NASA Astrophysics Data System (ADS)

Lock, Simon J.; Stewart, Sarah T.; Petaev, Michail I.; Leinhardt, Zoë; Mace, Mia T.; Jacobsen, Stein B.; Cuk, Matija

2018-04-01

The giant impact hypothesis remains the leading theory for lunar origin. However, current models struggle to explain the Moon's composition and isotopic similarity with Earth. Here we present a new lunar origin model. High-energy, high-angular-momentum giant impacts can create a post-impact structure that exceeds the corotation limit, which defines the hottest thermal state and angular momentum possible for a corotating body. In a typical super-corotation-limit body, traditional definitions of mantle, atmosphere, and disk are not appropriate, and the body forms a new type of planetary structure, named a synestia. Using simulations of cooling synestias combined with dynamic, thermodynamic, and geochemical calculations, we show that satellite formation from a synestia can produce the main features of our Moon. We find that cooling drives mixing of the structure, and condensation generates moonlets that orbit within the synestia, surrounded by tens of bars of bulk silicate Earth vapor. The moonlets and growing moon are heated by the vapor until the first major element (Si) begins to vaporize and buffer the temperature. Moonlets equilibrate with bulk silicate Earth vapor at the temperature of silicate vaporization and the pressure of the structure, establishing the lunar isotopic composition and pattern of moderately volatile elements. Eventually, the cooling synestia recedes within the lunar orbit, terminating the main stage of lunar accretion. Our model shifts the paradigm for lunar origin from specifying a certain impact scenario to achieving a Moon-forming synestia. Giant impacts that produce potential Moon-forming synestias were common at the end of terrestrial planet formation.

Cuspal Deflection of Premolars Restored with Bulk-Fill Composite Resins.

PubMed

Behery, Haytham; El-Mowafy, Omar; El-Badrawy, Wafa; Saleh, Belal; Nabih, Sameh

2016-01-01

This in vitro study compared cuspal deflection of premolars restored with three bulk-fill composite resins to that of incrementally-restored ones with a low-shrinkage silorane-based restorative material. Forty freshly-extracted intact human upper premolars were used. Reference points at buccal and palatal cusp tips were acid-etched and composite rods were horizontally bonded to them (TPH-Spectra-HV, Dentsply). Two acrylic resin guiding paths were made for each premolar to guide beaks of a digital micrometer used for cuspal deflection measurements. Standardized MOD cavities, 3 mm wide bucco-lingually and 3.5 mm deep, were prepared on each premolar. Prepared teeth were then equally divided into four groups (n = 10) and each group was assigned to one of four composite resin (QuiXX, Dentsply; X-tra fil, Voco; Tetric EvoCeram Bulk Fill, Ivoclar Vivadent; low-shrinkage Filtek LS, 3M/ESPE). Adper Single Bond-Plus, 3M/ESPE was used with all bulk-fill restoratives. LS-System Adhesive, 3M/ESPE was used with Filtek LS. For each prepared premolar, cuspal deflection was measured in microns as the difference between two readings between reference points before and after restoration completion. Means and SDs were calculated and data statistically-analyzed using One-way ANOVA and Tukey's test. Filtek LS showed the lowest mean cuspal deflection value 6.4(0.84)μm followed by Tetric EvoCeram Bulk Fill 10.1(1.2) μm and X-tra fil 12.4(1.35)μm, while QuiXX showed the highest mean 13(1.05)μm. ANOVA indicated significant difference among mean values of groups (p < 0.001). Tukey's test indicated no significant difference in mean values between QuiXX and X-tra fil (p = 0.637). Tetric EvoCeram Bulk Fill had significantly lower mean cuspal deflection compared with the two other bulk-fill composite resins tested. Filtek LS had the lowest significant mean cuspal deflection in comparison to all tested bulk-fill restoratives. The use of Tetric EvoCeram Bulk fill composite resin restorative for class II MOD cavities resulted in reduced cuspal deflection in comparison to the two other bulk-fill composite resins tested. The silorane-based Filtek LS restorative resulted in the least cuspal deflection in comparison to all tested bulk-fill composite restoratives. © 2016 Wiley Periodicals, Inc.

Physico-mechanical characteristics of commercially available bulk-fill composites.

PubMed

Leprince, Julian G; Palin, William M; Vanacker, Julie; Sabbagh, Joseph; Devaux, Jacques; Leloup, Gaetane

2014-08-01

Bulk-fill composites have emerged, arguably, as a new "class" of resin-based composites, which are claimed to enable restoration in thick layers, up to 4mm. The objective of this work was to compare, under optimal curing conditions, the physico-mechanical properties of most currently available bulk-fill composites to those of two conventional composite materials chosen as references, one highly filled and one flowable "nano-hybrid" composite. Tetric EvoCeram Bulk Fill (Ivoclar-Vivadent), Venus Bulk Fill (Heraeus-Kulzer), SDR (Dentsply), X-tra Fil (VOCO), X-tra Base (VOCO), Sonic Fill (Kerr), Filtek Bulk Fill (3M-Espe), Xenius (GC) were compared to the two reference materials. The materials were light-cured for 40s in a 2mm×2mm×25mm Teflon mould. Degree of conversion was measured by Raman spectroscopy, Elastic modulus and flexural strength were evaluated by three point bending, surface hardness using Vickers microindentation before and after 24h ethanol storage, and filler weight content by thermogravimetric analysis. The ratio of surface hardness before and after ethanol storage was considered as an evaluation of polymer softening. Data were analyzed by one-way ANOVA and post hoc Tukey's test (p=0.05). The mechanical properties of the bulk-fill composites were mostly lower compared with the conventional high viscosity material, and, at best, comparable to the conventional flowable composite. Linear correlations of the mechanical properties investigated were poor with degree of conversion (0.090.8). Softening in ethanol revealed differences in polymer network density between material types. The reduction of time and improvement of convenience associated with bulk-fill materials is a clear advantage of this particular material class. However, a compromise with mechanical properties compared with more conventional commercially-available nano-hybrid materials was demonstrated by the present work. Given the lower mechanical properties of most bulk-fill materials compared to a highly filled nano-hybrid composite, their use for restorations under high occlusal load is subject to caution. Further, the swelling behaviour of some of the bulk-fill materials may be a reason for concern, which highlights the critical requirement for a veneering material, not only to improve aesthetic quality of the translucent material, but to reduce the impact of degradation. Copyright © 2014 Elsevier Ltd. All rights reserved.

A correlated nickelate synaptic transistor.

PubMed

Shi, Jian; Ha, Sieu D; Zhou, You; Schoofs, Frank; Ramanathan, Shriram

2013-01-01

Inspired by biological neural systems, neuromorphic devices may open up new computing paradigms to explore cognition, learning and limits of parallel computation. Here we report the demonstration of a synaptic transistor with SmNiO₃, a correlated electron system with insulator-metal transition temperature at 130°C in bulk form. Non-volatile resistance and synaptic multilevel analogue states are demonstrated by control over composition in ionic liquid-gated devices on silicon platforms. The extent of the resistance modulation can be dramatically controlled by the film microstructure. By simulating the time difference between postneuron and preneuron spikes as the input parameter of a gate bias voltage pulse, synaptic spike-timing-dependent plasticity learning behaviour is realized. The extreme sensitivity of electrical properties to defects in correlated oxides may make them a particularly suitable class of materials to realize artificial biological circuits that can be operated at and above room temperature and seamlessly integrated into conventional electronic circuits.

Amplification of seismic waves beneath active volcanoes

NASA Astrophysics Data System (ADS)

Navon, O.; Lensky, N. G.; Collier, L.; Neuberg, J.; Lyakhovsky, V.

2003-04-01

Long-period (LP) seismic events are typical of many volcanoes and are attributed to energy leaking from waves traveling through the volcanic conduit or along the conduit - country-rock interface. The LP events are triggered locally, at the volcanic edifice, but the source of energy for the formation of tens of events per day is not clear. Energy may be supplied by volatile-release from a supersaturated melt. If bubbles are present in equilibrium with the melt in the conduit, and the melt is suddenly decompressed, transfer of volatiles from the supersaturated melt into the bubbles transforms stored potential energy into expansion work. For example, small dome collapses may decompress the conduit by a few bars and lead to solubility decrease, exsolution of volatiles and, consequently, to work done by the expansion of the bubbles under pressure. This energy is released over a timescale that is similar to that of LP events and may amplify the original weak seismic signals associated with the collapse. Using the formulation of Lensky et al. (2002), following the decompression, when the transfer of volatiles into bubbles is fast enough, expansion accelerates and the bulk viscosity of the bubbly magma is negative. New calculations show that under such conditions a sinusoidal P-wave is amplified. We note that seismic waves created by tectonic earthquakes that are not associated with net decompression, do not lead to net release of volatiles or to net expansion. In this case, the bulk viscosity is positive and waves traveling through the magma should attenuate. The proposed model explains how weak seismic signals may be amplified as they travel through a conduit that contains supersaturated bubbly magma. It provides the general framework for amplifying volcanic seismicity such as the signals associated with long-period events.

Resin additive improves performance of high-temperature hydrocarbon lubricants

NASA Technical Reports Server (NTRS)

Johnson, R. L.; Loomis, W. R.

1971-01-01

Paraffinic resins, in high temperature applications, improve strength of thin lubricant film in Hertzian contacts even though they do not increase bulk oil viscosity. Use of resin circumvents corrosivity and high volatility problems inherent with many chemical additives.

Circumventing shallow air contamination in Mid Ocean Ridge Basalts

NASA Astrophysics Data System (ADS)

Mukhopadhyay, Sujoy; Parai, Rita; Tucker, Jonathan; Middleton, Jennifer; Langmuir, Charles

2016-04-01

Noble gases in mantle-derived basalts provide a rich portrait of mantle degassing and surface-interior volatile exchange. However, the ubiquity of shallow-level air contamination frequently obscures the mantle noble gas signal. In a majority of samples, shallow air contamination dominates the noble gas budget. As a result, reconstructing the variability in heavy noble gas mantle source compositions and inferring the history of deep recycling of atmospheric noble gases is difficult. For example, in the gas-rich popping rock 2ΠD43, 129Xe/130Xe ratios reach 7.7±0.23 in individual step-crushes, but the bulk composition of the sample is close to air (129Xe/130Xe of 6.7). Here, we present results from experiments designed to elucidate the source of shallow air contamination in MORBs. Step-crushes were carried out to measure He, Ne, Ar and Xe isotopic compositions on two aliquots of a depleted popping glass that was dredged from between the Kane and Atlantis Fracture Zones of the Mid-Atlantic Ridge in May 2012. One aliquot was sealed in ultrapure N2 after dredge retrieval, while the other aliquot was left exposed to air for 3.5 years. The bulk 20Ne/22Ne and 129Xe/130Xe ratios measured in the aliquot bottled in ultrapure N2 are 12.3 and 7.6, respectively, and are nearly identical to the estimated mantle source values. On the other hand, step crushes in the aliquot left exposed to air for several years show Ne isotopic compositions that are shifted towards air, with a bulk 20Ne/22Ne of 11.5; the bulk 129Xe/130Xe, however, was close to 7.6. These results indicate that lighter noble gases exchange more efficiently between the bubbles trapped in basalt glass and air, suggesting a diffusive or kinetic mechanism for the incorporation of the shallow air contamination. Importantly, in Ne-Ar or Ar-Xe space, step-crushes from the bottled aliquot display a trend that can be easily fit with a simple two-component hyperbolic mixing between mantle and atmosphere noble gases. Step-crushes in the aliquot left exposed to air display significantly more scatter, which makes it difficult to fit a two-component mixing hyperbola and obtain the mantle source value for this aliquot. In summary, our simple and inexpensive experiment demonstrates that at least in some samples, significant air contamination is added after dredge retrieval from the ocean floor. Bottling samples in ultrapure N2 upon dredge retrieval can largely eliminate this component of shallow-level air contamination. As a result, the number of step crushes required to characterize a sample decreases and estimating the mantle source compositions of the basalts becomes significantly easier, which in turn leads to more refined estimates of mantle degassing and regassing rates.

Sensory characteristics and volatile composition of a cereal beverage fermented with Bifidobacterium breve NCIMB 702257.

PubMed

Salmerón, Ivan; Rozada, Raquel; Thomas, Keith; Ortega-Rivas, Enrique; Pandiella, Severino S

2014-04-01

Most of the commercialized lactic acid fermented products are dairy-based. Hence, the development of non-dairy fermented products with probiotic properties draws significant attention within the functional foods industry. The microorganisms used in such products have complex enzyme systems through which they generate diverse metabolites (volatile and non-volatile) that provide significant flavour attributes of importance for fermented foods. The correlation of the volatile flavour compounds of a malt beverage fermented with a Bifidobacterium breve strain with its unique sensory characteristics was performed. The volatile composition analysis exposed the presence of 12 components. Eight of these flavour volatiles were produced through the metabolic activity of the bifidobacteria strain. Notably acetic acid, of reported sour flavour characteristics, exhibited the greatest intensity. Four components of considerable organoleptic characteristics were identified as Maillard-derived products, namely maltol, pyranone, 2 (5H)-furanmethanol and 3-furanmethanol. The sensory evaluation exhibited that the fermented cereal beverage had a sour flavour with mild sweet and malty notes. These results indicate that the volatile compounds identified can be appointed as significant flavour markers of the novel fermented cereal beverage.

Volatiles and primary metabolites profiling in two Hibiscus sabdariffa (roselle) cultivars via headspace SPME-GC-MS and chemometrics.

PubMed

Farag, Mohamed A; Rasheed, Dalia M; Kamal, Islam M

2015-12-01

Hibiscus sabdariffa (roselle) is a plant of considerable commercial importance worldwide as functional food due to its organic acids, mucilage, anthocyanins, macro and micro-nutrients content. Although Hibiscus flowers are emerging as very competitive targets for phytochemical studies, very little is known about their volatile composition and or aroma, such knowledge can be suspected to be relevant for understanding its olfactory and taste properties. To provide insight into Hibiscus flower aroma composition and for its future use in food and or pharmaceutical industry, volatile constituents from 2 cultivars grown in Egypt, viz. Aswan and Sudan-1 were profiled using solid-phase microextraction (SPME) coupled to GCMS. A total of 104 volatiles were identified with sugar and fatty acid derived volatiles amounting for the major volatile classes. To reveal for cultivar effect on volatile composition in an untargeted manner, multivariate data analysis was applied. Orthogonal projection to latent structures-discriminant analysis (OPLS-DA) revealed for 1-octen-3-ol versus furfural/acetic acid enrichment in Aswan and Sudan-1 cvs., respectively. Primary metabolites contributing to roselle taste and nutritional value viz. sugars and organic acids were profiled using GC-MS after silylation. The impact of probiotic bacteria on roselle infusion aroma profile was further assessed and revealed for the increase in furfural production with Lactobacillus plantarum inoculation and without affecting its anthocyanin content. This study provides the most complete map for volatiles, sugars and organic acids distribution in two Hibiscus flower cultivars and its fermented product. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effect of different drying techniques on bioactive components, fatty acid composition, and volatile profile of robusta coffee beans.

PubMed

Dong, Wenjiang; Hu, Rongsuo; Chu, Zhong; Zhao, Jianping; Tan, Lehe

2017-11-01

This study investigated the effect of different drying techniques, namely, room-temperature drying (RTD), solar drying (SD), heat-pump drying (HPD), hot-air drying (HAD), and freeze drying (FD), on bioactive components, fatty acid composition, and the volatile compound profile of robusta coffee beans. The data showed that FD was an effective method to preserve fat, organic acids, and monounsaturated fatty acids. In contrast, HAD was ideal for retaining polyunsaturated fatty acids and amino acids. Sixty-two volatile compounds were identified in the differently dried coffee beans, representing 90% of the volatile compounds. HPD of the coffee beans produced the largest number of volatiles, whereas FD resulted in the highest volatile content. A principal component analysis demonstrated a close relationship between the HPD, SD, and RTD methods whereas the FD and HAD methods were significantly different. Overall, the results provide a basis for potential application to other similar thermal sensitive materials. Copyright © 2017 Elsevier Ltd. All rights reserved.

Propolis volatile compounds: chemical diversity and biological activity: a review

PubMed Central

2014-01-01

Propolis is a sticky material collected by bees from plants, and used in the hive as building material and defensive substance. It has been popular as a remedy in Europe since ancient times. Nowadays, propolis use in over-the-counter preparations, “bio”-cosmetics and functional foods, etc., increases. Volatile compounds are found in low concentrations in propolis, but their aroma and significant biological activity make them important for propolis characterisation. Propolis is a plant-derived product: its chemical composition depends on the local flora at the site of collection, thus it offers a significant chemical diversity. The role of propolis volatiles in identification of its plant origin is discussed. The available data about chemical composition of propolis volatiles from different geographic regions are reviewed, demonstrating significant chemical variability. The contribution of volatiles and their constituents to the biological activities of propolis is considered. Future perspectives in research on propolis volatiles are outlined, especially in studying activities other than antimicrobial. PMID:24812573

Volatile Composition of Some Cultivated and Wild Culinary-Medicinal Mushrooms from Hungary.

PubMed

Csóka, Mariann; Geosel, Andras; Amtmann, Maria; Korany, Kornel

2017-01-01

The volatile constituents of the fruiting bodies of 4 culinary-medicinal mushroom species (Agaricus bisporus, Boletus edulis, Cantharellus cibarius, and Hericium erinaceus) from Hungary were examined to review their aroma composition. Simultaneous distillation/extraction was applied to extract volatile compounds from fungi, and the values were measured with gas chromatography--mass spectrometry. Although the fragrances of fungi are not as characteristic as those of spices, several groups of volatile compounds have been found in mushrooms. The number of identified components ranged between 61 and 100, with a high ratio of 8-carbon volatiles generally occurring in fungi. Beyond common properties, individual attributes have been identified as well: an outstanding ratio of benzene compounds in champignons, numerous N-containing volatiles in boletes, carotenoid degradation products in chanterelles, and esters and fatty acids with a high carbon number in the lion's mane mushroom. The identification of these characteristic fragrance constituents can be very important in differentiating between species and confirming their presence in mushroom products.

40 CFR 761.289 - Compositing samples.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Remediation Waste and Porous Surfaces in Accordance With § 761.61(a)(6) § 761.289 Compositing samples. Compositing is a method of combining several samples of a specific type of bulk PCB remediation waste or... compositing bulk PCB remediation waste samples. These procedures are based on the method for selecting...

40 CFR 761.289 - Compositing samples.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Remediation Waste and Porous Surfaces in Accordance With § 761.61(a)(6) § 761.289 Compositing samples. Compositing is a method of combining several samples of a specific type of bulk PCB remediation waste or... compositing bulk PCB remediation waste samples. These procedures are based on the method for selecting...

From Aeolis Palus to the Bagnold Dunes field: Overview of martian soil analyses performed by ChemCam in Gale Crater

NASA Astrophysics Data System (ADS)

Cousin, A.; Meslin, P. Y.; Dehouck, E.; David, G.; Rapin, W.; Schröder, S.; Forni, O.; Gasnault, O.; Williams, A. J.; Lasue, J.; Stein, N.; Ehlmann, B. L.; Payre, V.; Anderson, R. B.; Blaney, D. L.; Bridges, N. T.; Clark, B. C.; Frydenvang, J.; Gasda, P. J.; Johnson, J. R.; Lanza, N.; l'Haridon, J.; Mangold, N.; Maurice, S.; Newsom, H. E.; Ollila, A.; Pinet, P. C.; Sautter, V.; Thomas, N. H.; Wiens, R. C.

2017-12-01

In situ analysis of the chemical and mineralogical composition of the martian soil, and the determination of its volatile inventory, can provide important constraints on the bulk composition of the martian crust, on its igneous diversity, but also on the physical and chemical weathering processes that have altered its primary igneous constituents. Transport processes that have occurred over long geological time scales, however, make this analysis quite complex, as constituents from different unknown sources are mixed together, and may have been sorted according to grain size or density. A meteoritic contribution is also present. Disentangling the influence of each of these processes requires the use of different analytical techniques, at different spatial scales, and at different locations over the planet. We will present an overview of the soil analyses obtained over the past 5 years by the ChemCam instrument on board MSL/Curiosity. Their specificity lies in their small spatial scale ( 300 μm), close to the average grains' size. At this scale, chemical trends are observed, resulting from the mixing of different end-members with different grain sizes: coarse felsic grains of likely local origin, fine grains with a basaltic composition close to soil compositions observed at other landing sites, but distinct from local rocks, and a fine-grained, Si-poor, volatile-rich component probably associated with the XRD-amorphous component detected by the CheMin instrument. The thin ablation depth associated with each laser shot ( 1 μm) enables us to analyse the surface of the grains, which is characterized by a strong, but variable hydrogen signal. These analyses provide constraints on the composition of a possible alteration rind or coating present at their surface. An extensive, multi-instrument investigation of active dunes (barchan and linear dunes) has also been carried out, revealing slight chemical differences with surrounding soils, and a more homogeneous composition, although chemical variations as a function of grain size are observed, with coarser grains enriched in mafic minerals. These results illustrate the still ongoing influence of aeolian transport on the physical sorting of loose, unconsolidated sediments. These results also provide ground truth for orbital IR observations of aeolian bedforms.

Evaluation of Double-Vacuum-Bag Process For Composite Fabrication

NASA Technical Reports Server (NTRS)

Hou, T. H.; Jensen, B. J.

2004-01-01

A non-autoclave vacuum bag process using atmospheric pressure alone that eliminates the need for external pressure normally supplied by an autoclave or a press is an attractive method for composite fabrication. This type of process does not require large capital expenditures for tooling and processing equipment. In the molding cycle (temperature/pressure profile) for a given composite system, the vacuum application point has to be carefully selected to achieve the final consolidated laminate net shape and resin content without excessive resin squeeze-out. The traditional single-vacuum- bag (SVB) process is best suited for molding epoxy matrix based composites because of their superior flow and the absence of reaction by-products or other volatiles. Other classes of materials, such as polyimides and phenolics, generate water during cure. In addition, these materials are commonly synthesized as oligomers using solvents to facilitate processability. Volatiles (solvents and reaction byproducts) management therefore becomes a critical issue. SVB molding, without additional pressure, normally fails to yield void-free quality composites for these classes of resin systems. A double-vacuum- bag (DVB) process for volatile management was envisioned, designed and built at the NASA Langley Research Center. This experimental DVB process affords superior volatiles management compared to the traditional SVB process. Void-free composites are consistently fabricated as measured by C-scan and optical photomicroscopy for high performance polyimide and phenolic resins.

Silicon isotopes in angrites and volatile loss in planetesimals

PubMed Central

Moynier, Frédéric; Savage, Paul S.; Badro, James; Barrat, Jean-Alix

2014-01-01

Inner solar system bodies, including the Earth, Moon, and asteroids, are depleted in volatile elements relative to chondrites. Hypotheses for this volatile element depletion include incomplete condensation from the solar nebula and volatile loss during energetic impacts. These processes are expected to each produce characteristic stable isotope signatures. However, processes of planetary differentiation may also modify the isotopic composition of geochemical reservoirs. Angrites are rare meteorites that crystallized only a few million years after calcium–aluminum-rich inclusions and exhibit extreme depletions in volatile elements relative to chondrites, making them ideal samples with which to study volatile element depletion in the early solar system. Here we present high-precision Si isotope data that show angrites are enriched in the heavy isotopes of Si relative to chondritic meteorites by 50–100 ppm/amu. Silicon is sufficiently volatile such that it may be isotopically fractionated during incomplete condensation or evaporative mass loss, but theoretical calculations and experimental results also predict isotope fractionation under specific conditions of metal–silicate differentiation. We show that the Si isotope composition of angrites cannot be explained by any plausible core formation scenario, but rather reflects isotope fractionation during impact-induced evaporation. Our results indicate planetesimals initially formed from volatile-rich material and were subsequently depleted in volatile elements during accretion. PMID:25404309

Composition of LHB Comets and Their Influence on the Early Earth Atmosphere Composition

NASA Technical Reports Server (NTRS)

Tornow, C.; Kupper, S.; Ilgner, M.; Kuehrt, E.; Motschmann, U.

2011-01-01

Two main processes were responsible for the composition of this atmosphere: chemical evolution of the volatile fraction of the accretion material forming the planet and the delivery of gasses to the planetary surface by impactors during the late heavy bombardment (LHB). The amount and composition of the volatile fraction influences the outgassing of the Earth mantle during the last planetary formation period. A very weakened form of outgassing activity can still be observed today by examining the composition of volcanic gasses. An enlightenment of the second process is based on the sparse records of the LHB impactors resulting from the composition of meteorites, observed cometary comas, and the impact material found on the Moon. However, for an assessment of the influence of the outgassing on the one hand and the LHB event on the other, one has to supplement the observations with numerical simulations of the formation of volatiles and their incorporation into the accretion material which is the precursors of planetary matter, comets and asteroids. These simulations are performed with a combined hydrodynamic-chemical model of the solar nebula (SN). We calculate the chemical composition of the gas and dust phase of the SN. From these data, we draw conclusions on the upper limits of the water content and the amount of carbon and nitrogen rich volatiles incorporated later into the accretion material. Knowing these limits we determine the portion of major gas compounds delivered during the LHB and compare it with the related quantities of the outgassed species.

A review of volatile compounds in tektites, and carbon content and isotopic composition of moldavite glass

NASA Astrophysics Data System (ADS)

Žák, Karel; SkáLA, Roman; Šanda, Zdeněk.; Mizera, Jiří.

2012-06-01

Tektites, natural silica-rich glasses produced during impact events, commonly contain bubbles. The paper reviews published data on pressure and composition of a gas phase contained in the tektite bubbles and data on other volatile compounds which can be released from tektites by either high-temperature melting or by crushing or milling under vacuum. Gas extraction from tektites using high-temperature melting generally produced higher gas yield and different gas composition than the low-temperature extraction using crushing or milling under vacuum. The high-temperature extraction obviously releases volatiles not only from the bubbles, but also volatile compounds contained directly in the glass. Moreover, the gas composition can be modified by reactions between the released gases and the glass melt. Published data indicate that besides CO2 and/or CO in the bubbles, another carbon reservoir is present directly in the tektite glass. To clarify the problem of carbon content and carbon isotopic composition of the tektite glass, three samples from the Central European tektite strewn field—moldavites—were analyzed. The samples contained only 35-41 ppm C with δ13C values in the range from -28.5 to -29.9‰ VPDB. This indicates that terrestrial organic matter was a dominant carbon source during moldavite formation.

Changes in volatile composition and sensory properties of Iranian ultrafiltered white cheese as affected by blends of Rhizomucor miehei protease or camel chymosin.

PubMed

Soltani, M; Sahingil, D; Gokce, Y; Hayaloglu, A A

2016-10-01

The effect of using various combinations of Rhizomucor miehei protease and camel chymosin (100:0, 75:25, 50:50, 25:75, and 0:100, respectively) on volatile composition and sensory scores in Iranian ultrafiltered white cheese was studied during 90d of ripening. A solid-phase microextraction-gas chromatography-mass spectrometric method was used for determining the volatile compounds of the cheeses. Forty compounds including esters (12), acids (6), ketones (9), alcohols (3), and miscellaneous compounds (10) were identified. The main classes of volatile components in the cheeses are esters, miscellaneous compounds, and ketones. The type and concentration of the coagulants influenced both volatile composition and sensory scores of the cheeses. Principal component analysis separated the cheeses based on the use of 2 coagulants in various combinations and ripening time. The cheeses produced using higher concentrations of R. miehei were separately located on the plot compared with the cheeses produced using higher concentrations of camel chymosin. Sensory evaluation of the cheeses showed that, in general, the cheeses produced using higher concentrations of camel chymosin received higher body and texture and odor and flavor scores than the cheese produced using higher concentrations of R. miehei. In conclusion, 2 combinations of R. miehei and camel chymosin (75:25 and 25:75, respectively) can be successfully used for the production of Iranian ultrafiltered white cheese, considering the results of volatile composition and sensory analysis. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Volatile components and continental material of planets

NASA Technical Reports Server (NTRS)

Florenskiy, K. P.; Nikolayeva, O. V.

1986-01-01

It is shown that the continental material of the terrestrial planets varies in composition from planet to planet according to the abundances and composition of true volatiles (H20, CO2, etc.) in the outer shells of the planets. The formation of these shells occurs very early in a planet's evolution when the role of endogenous processes is indistinct and continental materials are subject to melting and vaporizing in the absence of an atmosphere. As a result, the chemical properties of continental materials are related not only to fractionation processes but also to meltability and volatility. For planets retaining a certain quantity of true volatile components, the chemical transformation of continental material is characterized by a close interaction between impact melting vaporization and endogeneous geological processes.

Volatile transfer and recycling at convergent margins: Mass-balance and insights from high-P/T metamorphic rocks

NASA Astrophysics Data System (ADS)

Bebout, Gray E.

The efficiency with which volatiles are deeply subducted is governed by devolatilization histories and the geometries and mechanisms of fluid transport deep in subduction zones. Metamorphism along the forearc slab-mantle interface may prevent the deep subduction of many volatile components (e.g., H2O, Cs, B, N, perhaps As, Sb, and U) and result in their transport in fluids toward shallower reservoirs. The release, by devolatilization, and transport of such components toward the seafloor or into the forearc mantle wedge, could in part explain the imbalances between the estimated amounts of subducted volatiles and the amounts returned to Earth's surface. The proportion of the initially subducted volatile component that is retained in rocks subducted to depths greater than those beneath magmatic arcs (>100 km) is largely unknown, complicating assessments of deep mantle volatile budgets. Isotopic and trace element data and volatile contents for the Catalina Schist, the Franciscan Complex, and eclogite-facies complexes in the Alps (and elsewhere) provide insight into the nature and magnitude of fluid production and transport deep in subduction zones and into the possible effects of metamorphism on the compositions of subducting rocks. Compatibilities of the compositions of the subduction-related rocks and fluids with the isotopic and trace element compositions of various mantle-derived materials (igneous rocks, xenoliths, serpentinite seamounts) indicate the potential to trace the recycling of rock and fluid reservoirs chemically and isotopically fractionated during subduction-zone metamorphism.

Fabrication and evaluation of low fiber content alumina fiber/aluminum composites

NASA Technical Reports Server (NTRS)

Hack, J. E.; Strempek, G. C.

1980-01-01

The mechanical fabrication of low volume percent fiber, polycrystalline alumina fiber reinforced aluminum composites was accomplished. Wire preform material was prepared by liquid-metal infiltration of alumina fiber bundles. The wires were subsequently encapsulated with aluminum foil and fabricated into bulk composite material by hot-drawing. Extensive mechanical, thermal and chemical testing was conducted on preform and bulk material to develop a process and material data base. In addition, a preliminary investigation of mechanical forming of bulk alumina fiber reinforced aluminum composite material was conducted.

Partial melting of carbonated pelite at 3-7 GPa and deep cycling of CO2 and H2O in subduction zones

NASA Astrophysics Data System (ADS)

Tsuno, K.; Dasgupta, R.; Danielson, L. R.; Righter, K.

2011-12-01

The exchange of water and carbon dioxide between the Earth's crustal rocks and the interior is important for understanding geochemical and geophysical evolution of the planet on geologic timescale. Subduction of pelitic sediments is a key mechanism for volatile introduction to the mantle but the high-pressure behavior of H2O+ CO2 bearing sediments is only constrained for alumina-rich, low-Mg# bulk compositions [1, 2]. However, the ocean-floor sediments for many subduction zones that contain both water and CO2 are alumina-poor and have higher Mg#. To constrain the melting behavior of a model alumina poor carbonated pelite, we performed new experiments. Piston cylinder (3 GPa) and multianvil (5 and 7 GPa) experiments were conducted between 800 and 1150 °C, using a model sediment composition containing 1 wt.% H2O and 5 wt.% CO2 (trace vapor-present at subsolidus conditions). The choice of the bulk composition was aimed to model the loss of siliceous hydrous fluid during the shallow part of subduction. We determined the solidus temperatures between 800 and 850 °C at 3 GPa, 900 and 950 °C at 5 GPa, and <1000 °C at 7 GPa. The subsolidus phases include cpx, garnet, coesite, rutile, phengite, and calcitess at 3 GPa, and kyanite comes in at 5 GPa. Hydrous rhyolitic silicate melt was observed at 3 GPa and up to 1150 °C. The near-solidus melt at 5-7 GPa was K-rich and calcio-carbonatitic, in contrast to the previous experimental results in alumina-rich and low Mg# bulk composition [1, 2], which showed the stability of Al-rich trachyitic silicate melt at near-solidus temperatures up to 5 GPa, and replaced by carbonate melt only at ≥5.5 GPa. Carbonate-silicate melt immiscibility was observed at 5 GPa, 1100 °C in our study. The phengite-out boundary is located between 850 and 900 °C at 3 GPa, between 1000 and 1100 °C at 5 GPa, and <1000 °C at 7 GPa. The crystalline carbonate-out boundary is between 950 and 1000 °C at 3 and 5 GPa, and <1000 °C at 7 GPa. Comparison of our results, in terms of the P-T locations of the solidus, phengite- and carbonate-out boundaries, to the thermal structures of the slab-surface in cold-intermediate subduction zones indicates that most of the phengite-bound H2O and carbonate-bound CO2 are recycled into the deep upper mantle (~200 km depth). On the other hand, substantial amounts of C-O-H volatiles, in the form of either hydrous silicate melt or K-rich calcio-carbonatitic melt, are likely to be released from relatively hot subducting slabs. The observation of carbonate melt inclusion in cpx and garnet in deeply subducted carbonate-rich sediments [3] might be explained by our experimental results that carbonatite is the stable near-solidus sediment melt at deep sub-arc depths. [1] Thomsen, T.B. and Schmidt, M.W. 2008, EPSL 267, 17-31. [2] Grassi, D. and Schmidt, M.W. 2011, J. Petrol. 52, 765-789. [3] Korsakov, A.V., and Hermann, J. 2006, EPSL, 104-118.

Volatile composition and sensory characteristics of onion powders prepared by convective drying.

PubMed

Choi, So Mang; Lee, Dong-Jin; Kim, Jong-Yea; Lim, Seung-Taik

2017-09-15

Volatile composition and sensory characteristics of onion powders prepared by convective drying at different temperatures (50, 70, and 90°C) were investigated. Dipropyl disulfide was the major volatile compound in fresh onion (77.70% of total volatile compounds). However it was considerably lost during drying, reaching 6.93-32.25µg/g solids. Dipropyl disulfide showed a positive correlation with green sensory attribute perceived by descriptive sensory analysis. Thiophenes, which were responsible for caramel and sweet attributes, were produced by drying especially when the drying temperature was high. Aldehydes, another type of volatile compound found in fresh onion, showed a positive correlation with humidity. The aldehyde content in dried onion was the highest at the lowest drying temperature, possibly because the aldehydes were produced by the residual enzymes in fresh onion. Using a low temperature for drying was ideal to retain the aroma of fresh onion. Copyright © 2017 Elsevier Ltd. All rights reserved.

The volatile composition of comets

NASA Technical Reports Server (NTRS)

Weaver, H. A.

1988-01-01

Comets may be our best probes of the physical and chemical conditions in the outer regions of the solar nebula during that crucial period when the planets formed. The volatile composition of cometary nuclei can be used to decide whether comets are the product of a condensation sequence similar to that invoked to explain the compositions of the planets and asteroids, or if comets are simply agglomerations of interstellar grains which have been insignificantly modified by the events that shaped the other bodies in the solar system. Although cometary nuclei are not generally accessible to observation, observations of cometary comae can illuminate at least some of the mysteries of the nuclei provided one has a detailed knowledge of the excitation conditions in the coma and also has access to basic atomic and molecular data on the many species present in comets. Examined here is the status of our knowledge of the volatile composition of cometary nuclei and how these data are obtained.

Characterization of microbial and chemical composition of shuttle wet waste with permanent gas and volatile organic compound analyses

NASA Astrophysics Data System (ADS)

Peterson, B. V.; Hummerick, M.; Roberts, M. S.; Krumins, V.; Kish, A. L.; Garland, J. L.; Maxwell, S.; Mills, A.

2004-01-01

Solid-waste treatment in space for Advanced Life Support, ALS, applications requires that the material can be safely processed and stored in a confined environment. Many solid-wastes are not stable because they are wet (40-90% moisture) and contain levels of soluble organic compounds that can contribute to the growth of undesirable microorganisms with concomitant production of noxious odors. In the absence of integrated Advanced Life Support systems on orbit, permanent gas, trace volatile organic and microbiological analyses were performed on crew refuse returned from the volume F "wet" trash of three consecutive Shuttle missions (STS-105, 109, and 110). These analyses were designed to characterize the short-term biological stability of the material and assess potential crew risks resulting from microbial decay processes during storage. Waste samples were collected post-orbiter landing and sorted into packaging material, food waste, toilet waste, and bulk liquid fractions deposited during flight in the volume F container. Aerobic and anaerobic microbial loads were determined in each fraction by cultivation on R2A and by acridine orange direct count (AODC). Dry and ash weights were performed to determine both water and organic content of the materials. Experiments to determine the aerobic and anaerobic biostability of refuse stored for varying periods of time were performed by on-line monitoring of CO 2 and laboratory analysis for production of hydrogen sulfide and methane. Volatile organic compounds and permanent gases were analyzed using EPA Method TO15 by USEPA et al. [EPA Method TO15, The Determination of Volatile Organic Compounds (VOCs) in Ambient Air using SUMMA, Passivated Canister Sampling and Gas Chromatographic Analysis, 1999] with gas chromatography/mass spectrometry and by gas chromatography with selective detectors. These baseline measures of waste stream content, labile organics, and microbial load in the volume F Shuttle trash provide data for waste subsystem analysis and atmospheric management within the ALS Project.

Characterization of microbial and chemical composition of shuttle wet waste with permanent gas and volatile organic compound analyses

NASA Technical Reports Server (NTRS)

Peterson, B. V.; Hummerick, M.; Roberts, M. S.; Krumins, V.; Kish, A. L.; Garland, J. L.; Maxwell, S.; Mills, A.

2004-01-01

Solid-waste treatment in space for Advanced Life Support, ALS, applications requires that the material can be safely processed and stored in a confined environment. Many solid-wastes are not stable because they are wet (40-90% moisture) and contain levels of soluble organic compounds that can contribute to the growth of undesirable microorganisms with concomitant production of noxious odors. In the absence of integrated Advanced Life Support systems on orbit, permanent gas, trace volatile organic and microbiological analyses were performed on crew refuse returned from the volume F "wet" trash of three consecutive Shuttle missions (STS-105, 109, and 110). These analyses were designed to characterize the short-term biological stability of the material and assess potential crew risks resulting from microbial decay processes during storage. Waste samples were collected post-orbiter landing and sorted into packaging material, food waste, toilet waste, and bulk liquid fractions deposited during flight in the volume F container. Aerobic and anaerobic microbial loads were determined in each fraction by cultivation on R2A and by acridine orange direct count (AODC). Dry and ash weights were performed to determine both water and organic content of the materials. Experiments to determine the aerobic and anaerobic biostability of refuse stored for varying periods of time were performed by on-line monitoring of CO2 and laboratory analysis for production of hydrogen sulfide and methane. Volatile organic compounds and permanent gases were analyzed using EPA Method TO15 by USEPA et al. [EPA Method TO15, The Determination of Volatile Organic Compounds (VOCs) in Ambient Air using SUMMA, Passivated Canister Sampling and Gas Chromatographic Analysis,1999] with gas chromatography/mass spectrometry and by gas chromatography with selective detectors. These baseline measures of waste stream content, labile organics, and microbial load in the volume F Shuttle trash provide data for waste subsystem analysis and atmospheric management within the ALS Project. Published by Elsevier Ltd on behalf of COSPAR.

Molecular structure impacts on secondary organic aerosol formation from glycol ethers

NASA Astrophysics Data System (ADS)

Li, Lijie; Cocker, David R.

2018-05-01

Glycol ethers, a class of widely used solvents in consumer products, are often considered exempt as volatile organic compounds based on their vapor pressure or boiling points by regulatory agencies. However, recent studies found that glycol ethers volatilize at ambient conditions nearly as rapidly as the traditional high-volatility solvents indicating the potential of glycol ethers to form secondary organic aerosol (SOA). This is the first work on SOA formation from glycol ethers. The impact of molecular structure, specifically -OH, on SOA formation from glycol ethers and related ethers are investigated in the work. Ethers with and without -OH, with methyl group hindrance on -OH and with -OH at different location are studied in the presence of NOX and under "NOX free" conditions. Photooxidation experiments under different oxidation conditions confirm that the processing of ethers is a combination of carbonyl formation, cyclization and fragmentation. Bulk SOA chemical composition analysis and oxidation products identified in both gas and particle phase suggests that the presence and location of -OH in the carbon bond of ethers determine the occurrence of cyclization mechanism during ether oxidation. The cyclization is proposed as a critical SOA formation mechanism to prevent the formation of volatile compounds from fragmentation during the oxidation of ethers. Glycol ethers with -CH2-O-CH2CH2OH structure is found to readily form cyclization products, especially with the presence of NOx, which is more relevant to urban atmospheric conditions than without NOx. Glycol ethers are evaluated as dominating SOA precursors among all ethers studied. It is estimated that the contribution of glycol ethers to anthropogenic SOA is roughly 1% of the current organic aerosol from mobile sources. The contribution of glycol ethers to anthropogenic SOA is roughly 1% of the current organic aerosol from mobile sources and will play a more important role in future anthropogenic SOA formation.

Characterization of microbial and chemical composition of shuttle wet waste with permanent gas and volatile organic compound analyses.

PubMed

Peterson, B V; Hummerick, M; Roberts, M S; Krumins, V; Kish, A L; Garland, J L; Maxwell, S; Mills, A

2004-01-01

Solid-waste treatment in space for Advanced Life Support, ALS, applications requires that the material can be safely processed and stored in a confined environment. Many solid-wastes are not stable because they are wet (40-90% moisture) and contain levels of soluble organic compounds that can contribute to the growth of undesirable microorganisms with concomitant production of noxious odors. In the absence of integrated Advanced Life Support systems on orbit, permanent gas, trace volatile organic and microbiological analyses were performed on crew refuse returned from the volume F "wet" trash of three consecutive Shuttle missions (STS-105, 109, and 110). These analyses were designed to characterize the short-term biological stability of the material and assess potential crew risks resulting from microbial decay processes during storage. Waste samples were collected post-orbiter landing and sorted into packaging material, food waste, toilet waste, and bulk liquid fractions deposited during flight in the volume F container. Aerobic and anaerobic microbial loads were determined in each fraction by cultivation on R2A and by acridine orange direct count (AODC). Dry and ash weights were performed to determine both water and organic content of the materials. Experiments to determine the aerobic and anaerobic biostability of refuse stored for varying periods of time were performed by on-line monitoring of CO2 and laboratory analysis for production of hydrogen sulfide and methane. Volatile organic compounds and permanent gases were analyzed using EPA Method TO15 by USEPA et al. [EPA Method TO15, The Determination of Volatile Organic Compounds (VOCs) in Ambient Air using SUMMA, Passivated Canister Sampling and Gas Chromatographic Analysis,1999] with gas chromatography/mass spectrometry and by gas chromatography with selective detectors. These baseline measures of waste stream content, labile organics, and microbial load in the volume F Shuttle trash provide data for waste subsystem analysis and atmospheric management within the ALS Project. Published by Elsevier Ltd on behalf of COSPAR.

Volatile compounds in shergottite and nakhlite meteorites

NASA Technical Reports Server (NTRS)

Gooding, James L.; Aggrey, Kwesi E.; Muenow, David W.

1990-01-01

Since discovery of apparent carbonate carbon in Nakhla, significant evidence has accumulated for occurrence of volatile compounds in shergotties and nakhlites. Results are presented from a study of volatile compounds in three shergottites, one nakhlite, and three eucrite control samples. Shergotties ALHA77005, EETA79001, and Shergotty, and the nakhlite Nakhla, all contain oxidized sulfur (sulfate) of preterrestrial origin; sulfur oxidation is most complete in EETA79001/Lith-C. Significant bulk carbonate was confirmed in Nakhla and trace carbonate was substantiated for EETA79001, all of which appears to be preterrestrial in origin. Chlorine covaries with oxidized sulfur, whereas carbonate and sulfate are inversely related. These volatile compounds were probably formed in a highly oxidizing, aqueous environment sometime in the late stage histories of the rocks that are now represented as meteorites. They are consistent with the hypothesis that shergottite and nakhlite meteorites originated on Mars and that Mars has supported aqueous geochemistry during its history.

Inter-specific variation in headspace scent volatiles composition of four commercially cultivated jasmine flowers.

PubMed

Bera, Paramita; Kotamreddy, Jhansi Narmada Reddy; Samanta, Tanmoy; Maiti, Saborni; Mitra, Adinpunya

2015-01-01

Jasmines are commercially grown for their fragrant flowers and essential oil production. The flowers of jasmine emit sweet-smelling fragrance from evening till midnight. This study was designed to study the composition and inter-specific variation of the emitted scent volatiles from flowers of four commercially cultivated Jasminum species namely, Jasminum sambac, Jasminum auriculatum, Jasminum grandiflorum and Jasminum multiflorum. Gas chromatography-mass spectrometry analysis revealed that the scent volatiles composition of these flowers was predominantly enriched with both terpenoid and benzenoid compounds. Linalool and (3E,6E)-α-farnesene were identified as the major monoterpene and sesquiterpene in all the four species, respectively. The most abundant benzenoid detected in all flowers was benzyl acetate. Comparison of volatile profiles indicated a variation in fragrance contents and types emitted from these four jasmine flowers. The outcome of this study shall help in elucidating the enzymes and genes of fragrance biosynthesis in jasmines and in aiming to create flowers with improved scent quality.

Chemical composition and antimicrobial activity of the volatile fractions from leaves and flowers of the wild Iraqi Kurdish plant Prangos peucedanifolia FENZL.

PubMed

Brusotti, Gloria; Ibrahim, Mohammed Farhad; Dentamaro, Alessandra; Gilardoni, Gianluca; Tosi, Solveig; Grisoli, Pietro; Dacarro, Cesare; Guglielminetti, Maria Lidia; Hussain, Faiq Hama Saeed; Caccialanza, Gabriele; Vidari, Giovanni

2013-02-01

The volatile fractions isolated from Prangos peucedanifolia FENZL leaves and flowers were investigated for their phytochemical composition and biological properties. Flower and leaf hydrodistillation afforded 3.14 and 0.49 g of yellowish oils in 1.25 and 0.41% yields, respectively, from dry vegetable materials. According to the GC-FID and GC/MS analyses, 36 (99.35% of the total oil composition) and 26 compounds (89.12%) were identified in the two oils, respectively. The major constituents in the flower volatile fraction were β-pinene (35.58%), α-pinene (22.13%), and β-phellandrene (12.54%), while m-cresol (50.38%) was the main constituent of the leaf volatile fraction. The antimicrobial activity was evaluated against several bacterial and fungal strains, on the basis of the minimum inhibitory concentration (MIC) by the micro- and macrodilution methods. The two volatile fractions showed moderate antifungal and antibacterial activities, especially against Trichophyton rubrum (MIC of 2×10(3) μg/ml), Streptococcus mutans, Streptococcus pyogenes, and Staphylococcus aureus (MIC≤1.9×10(3) μg/ml for all). Copyright © 2013 Verlag Helvetica Chimica Acta AG, Zürich.

Samples for estimating primary volatiles in Martian magmas and ancient atmospheric pressures on Mars

NASA Technical Reports Server (NTRS)

Anderson, A. T., Jr.

1988-01-01

Inclusions of glass are likely to be present in phenocrysts in volcanic rocks from Mars, because these occur in volcanic rocks from both Earth and Moon. The usefulness of the inclusions depends upon their size and composition. The compositions of tiny inclusions may be modified by diffusion during growth of the enclosing crystal, the modifications increasing with melt viscosity (silica). Slow cooling results in crystallization and possible redistribution of volatiles, the effects increasing with decreasing silica. Primary volatile concentrations are best sought in inclusions larger than about 50 micrometer diameter in olivine or chromite crystals from quickly cooled basaltic scoria. Such crystals may be present in sands, but it would be preferable to extract them from individual rocks which could be dated and compositionally characterized. This would allow eventual understanding of the role of time and place in outgassing and volcanism on Mars. Analyses of volatiles in inclusions of more siliceous glass in non-basaltic rocks will reveal whether deep outgassing occurs and whether surface volatiles are recycled. Most volcanic crystals contain inclusions, but large inclusions can be uncommon. In the case of terrestrial basalts sample masses of several hundred grams are generally sufficient.

Chemistry, Mineralogy, and Grain Properties at Namib and High Dunes, Bagnold Dune Field, Gale Crater, Mars: A Synthesis of Curiosity Rover Observations: Bagnold Dune Sands Composition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ehlmann, B. L.; Edgett, K. S.; Sutter, B.

The Mars Science Laboratory Curiosity rover performed coordinated measurements to examine the textures and compositions of aeolian sands in the active Bagnold dune field. The Bagnold sands are rounded to subrounded, very fine- to medium- sized (~45-500 µm) with ≥6 distinct grain colors. In contrast to sands examined by Curiosity in a dust-covered, inactive bedform called Rocknest and soils at other landing sites, Bagnold sands are darker, less red, better sorted, have fewer silt-sized or smaller grains, and show no evidence for cohesion. Nonetheless, Bagnold mineralogy and Rocknest mineralogy are similar with plagioclase, olivine, and pyroxenes in similar proportions comprisingmore » >90% of crystalline phases, along with a substantial amorphous component (35% ± 15%). Yet, Bagnold and Rocknest bulk chemistry differ. Bagnold sands are Si-enriched relative to other soils at Gale crater, and H 2O, S, and Cl are lower relative to all previously measured martian soils and most Gale crater rocks. Mg, Ni, Fe, and Mn are enriched in the coarse-sieved fraction of Bagnold sands, corroborated by VNIR spectra that suggest enrichment of olivine. Together, patterns in major element chemistry and volatile release data indicate two distinctive volatile reservoirs in martian soils: (1) amorphous components in the sand-sized fraction (represented by Bagnold) that are Si-enriched, hydroxylated alteration products and/or impact or volcanic glasses; and (2) amorphous components in the fine fraction (<40 µm; represented by Rocknest and other bright soils) that are Fe-, S-, and Cl-enriched with low Si and adsorbed and structural H 2O.« less

Chemistry, Mineralogy, and Grain Properties at Namib and High Dunes, Bagnold Dune Field, Gale Crater, Mars: A Synthesis of Curiosity Rover Observations: Bagnold Dune Sands Composition

DOE PAGES

Ehlmann, B. L.; Edgett, K. S.; Sutter, B.; ...

2017-06-12

The Mars Science Laboratory Curiosity rover performed coordinated measurements to examine the textures and compositions of aeolian sands in the active Bagnold dune field. The Bagnold sands are rounded to subrounded, very fine- to medium- sized (~45-500 µm) with ≥6 distinct grain colors. In contrast to sands examined by Curiosity in a dust-covered, inactive bedform called Rocknest and soils at other landing sites, Bagnold sands are darker, less red, better sorted, have fewer silt-sized or smaller grains, and show no evidence for cohesion. Nonetheless, Bagnold mineralogy and Rocknest mineralogy are similar with plagioclase, olivine, and pyroxenes in similar proportions comprisingmore » >90% of crystalline phases, along with a substantial amorphous component (35% ± 15%). Yet, Bagnold and Rocknest bulk chemistry differ. Bagnold sands are Si-enriched relative to other soils at Gale crater, and H 2O, S, and Cl are lower relative to all previously measured martian soils and most Gale crater rocks. Mg, Ni, Fe, and Mn are enriched in the coarse-sieved fraction of Bagnold sands, corroborated by VNIR spectra that suggest enrichment of olivine. Together, patterns in major element chemistry and volatile release data indicate two distinctive volatile reservoirs in martian soils: (1) amorphous components in the sand-sized fraction (represented by Bagnold) that are Si-enriched, hydroxylated alteration products and/or impact or volcanic glasses; and (2) amorphous components in the fine fraction (<40 µm; represented by Rocknest and other bright soils) that are Fe-, S-, and Cl-enriched with low Si and adsorbed and structural H 2O.« less

Un-Earth-like interiors of the Earth-like planets

NASA Astrophysics Data System (ADS)

Shim, S. H. D.; Nisr, C.; Pagano, M.; Chen, H.; Ko, B.; Noble, S.; Leinenweber, K. D.; Young, P.; Desch, S. J.

2015-12-01

A number of exoplanets have been described as "Earth-like" planets (or even exo-earths) based on the mass-radius relations. Yet, significant variations have been documented in elemental abundances of planet-hosting stars, which will result in very different structures and processes in the interiors of rocky exoplanets. Recent data suggest that the Mg/Si ratio can be as small as less than 1 and as large as more than 2, opening the possibilities for the upper mantles to be dominated by pyroxene and olivine, respectively, and the lower mantles to be dominated by bridgmanite and ferropericlase, respectively. The changes in mineralogy will alter key properties, such as discontinuity structures (and therefore scale of mantle mixing), viscosity, and volatiles storage, of the mantle. Partial melting of such mantles would result in different compositions of the crusts, affecting the tectonics. However, the prediction should be made carefully because oxygen fugacity and contents of volatiles can change the mineralogy even for the same bulk composition. In extremely reducing proto-planetary disks, carbides will form instead of oxides and silicates, and become main constituents of planets in the system. Because carbides have high thermal conductivity and low thermal expansivity, internal heat transport of such planets may be dominated by conduction and mantle mixing would be much more limited than that of the Earth. However, the behaviors and properties of carbides need to be understood better at high pressure and high temperature. Some rocky exoplanets may have very thick layers of water and other icy materials. Interactions between ice (or fluid) and rock at extreme conditions would be the key to understand dynamics and habitability of such exoplanets.

The fate of moderately volatile elements during planetary formation in the inner Solar System

NASA Astrophysics Data System (ADS)

Pringle, E. A.; Moynier, F.

2017-12-01

Moderately volatile element abundances are variable among inner Solar System bodies, with differing degrees of depletion compared to chondrites. These variations are a consequence of the processes of planetary formation. The conditions and the specific mechanisms of planetary accretion and differentiation can be investigated by analyzing the stable isotope compositions of terrestrial and extraterrestrial samples. The moderately volatile lithophile elements are particularly useful to distinguish between the effects of accretion and those of core formation. Recent work has shown isotope variations in inner Solar System bodies for the moderately volatile elements Zn and K. The purely lithophile nature of Rb (in contrast to Zn) and the higher volatility of Rb compared to K make Rb an ideal element with which to further study moderately volatile element depletion. We have developed a new method for the high-precision measurement of Rb isotope ratios by MC-ICP-MS. Terrestrial rocks define a narrow range in Rb isotope composition, indicating that Rb isotope fractionation during igneous differentiation is limited (<30 ppm/amu). Larger Rb isotope variations are observed in extraterrestrial materials. Carbonaceous chondrites display a trend toward lighter Rb isotope composition coupled with decreasing Rb/Sr, opposite to the effect expected if their volatile element variations were caused by evaporative loss of Rb. This relationship indicates that the volatile element abundance variations in carbonaceous chondrites are not due to evaporation or condensation, but rather are due to the mixing of chemically and isotopically distinct primordial reservoirs. In contrast, there is a clear signature of Rb loss during evaporation in volatile-depleted achondrites and lunar rocks. Significant heavy isotope enrichments (up to several per mil for 87Rb/85Rb) are found for volatile-depleted planetesimals, including eucrites. In addition, lunar rocks also display heavy Rb isotope enrichments compared to the BSE. The most likely cause of these variations is Rb isotope fractionation due to evaporation during accretion.

A composite system approach to aircraft cabin fire safety

NASA Technical Reports Server (NTRS)

Kourtides, D. A.; Parker, J. A.; Gilwee, W. J., Jr.; Lerner, N. R.; Hilado, C. J.; Labossiere, L. A.; Hsu, M.-T.

1976-01-01

The thermochemical and flammability characteristics of two polymeric composites currently in use and seven others being considered for use as aircraft interior panels are described. The properties studied included: (1) limiting oxygen index of the composite constituents; (2) fire containment capability of the composite; (3) smoke evolution from the composite; (4) thermogravimetric analysis; (5) composition of the volatile products of thermal degradation; and (6) relative toxicity of the volatile products of pyrolysis. The performance of high-temperature laminating resins such as bismaleimides is compared with the performance of phenolics and epoxies. The relationship of increased fire safety with the use of polymers with high anaerobic char yield is shown. Processing parameters of one of the bismaleimide composites is detailed.

A composite system approach to aircraft cabin fire safety

NASA Technical Reports Server (NTRS)

Kourtides, D. A.; Parker, J. A.; Gilwee, W. J., Jr.; Lerner, N. R.; Hilado, C. J.; Labossiere, L. A.; Hsu, M. T. S.

1976-01-01

The thermochemical and flammability characteristics of two polymeric composites currently in use and seven others being considered for use as aircraft interior panels are described. The properties studied included: (1) limiting oxygen index of the composite constituents; (2) fire containment capability of the composite; (3) smoke evolution from the composite; (4) thermogravimetric analysis; (5) composition of the volatile products of thermal degradation; and (6) relative toxicity of the volatile products of pyrolysis. The performance of high temperature laminating resins such as bismaleimides is compared with the performance of phenolics and epoxies. The relationship of increased fire safety with the use of polymers with high anaerobic char yield is shown. Processing parameters of one of the baremaleimide composites are detailed.

Experimental Constraints on Silicic Slab Melt and Depleted Mantle Reaction in the Presence of CO2-H2O: Implications for the Origin of Mid Lithospheric Discontinuity

NASA Astrophysics Data System (ADS)

Saha, S.; Dasgupta, R.; Tsuno, K.

2016-12-01

Seismic shear wave velocity, VS drop (upto 24% and mostly 2-7%) observed globally beneath continents at depths of 60-160 km, known as the Mid Lithospheric Discontinuity (MLD) [e.g., 1], is an enigmatic feature of cratons whose origin is highly debated [e.g., 2, 3]. One of the mechanisms that can explain the MLD is the presence of volatile bearing phases such as partial melts and/or hydrous or carbonate minerals at depths. However, the compositional vector and geodynamic scenario required for their formation and the proportion and composition of infiltrating melt or fluid that may lead to their stability is poorly known at present. We performed high P-T experiments equilibrating a depleted peridotite (Mg# 92) with variable proportion of a H2O-CO2 bearing silicic melt, interaction that could occur during the formation of continents by imbrication of slabs. The first set of experiments were performed with 10 wt.% melt (0.9 wt.% H2O and 0.5 wt.% CO2 in the bulk) at 950-1175 °C at 3 GPa using a piston cylinder and 950-1150 °C at 4 GPa using a multi anvil apparatus. Olivine, opx, cpx, garnet/spinel and phlogopite (5-6%) are present in all runs. Amphibole (3.5-9.5%) is present at 3 GPa and ≤1050 °C. Magnesite ( 1%) is present at ≤1000 °C at 3 and ≤1050 °C at 4 GPa. Trace melt is observed along the grain boundaries above 1000 °C at 3 GPa and 1050 ° C at 4 GPa, respectively. Mineral modes obtained by mass balance calculations, ignoring the presence of melts, were used to calculate VS of the resulting assemblages [4]. The calculated drops in VS at 3 GPa (3.8-4.5%) and 4 GPa (1.6-3.2%) are well within the range of velocity drops for MLDs observed globally. Further experiments on different melt-rock ratios are underway and will constrain how modal proportion of hydrous and carbonate minerals varies as a function of melt:rock ratio and bulk volatile contents. [1] Abt et al., 2010, JGR; [2] Rader et al., 2015, G3; [3] Karato et al., 2015, NatGeo [4] Abers & Hacker, 2016, G3

PROCESS FOR CONTINUOUSLY SEPARATING IRRADIATION PRODUCTS OF THORIUM

DOEpatents

Hatch, L.P.; Miles, F.T.; Sheehan, T.V.; Wiswall, R.H.; Heus, R.J.

1959-07-01

A method is presented for separating uranium-233 and protactinium from thorium-232 containing compositions which comprises irradiating finely divided particles of said thorium with a neutron flux to form uranium-233 and protactinium, heating the neutron-irradiated composition in a fluorine and hydrogen atmosphere to form volatile fluorides of uranium and protactinium and thereafter separating said volatile fluorides from the thorium.

Analysis of Structure and Composition of Bacterial Core Communities in Mature Drinking Water Biofilms and Bulk Water of a Citywide Network in Germany

PubMed Central

Henne, Karsten; Kahlisch, Leila; Brettar, Ingrid

2012-01-01

The bacterial core communities of bulk water and corresponding biofilms of a more than 20-year-old drinking water network were compared using 16S rRNA single-strand confirmation polymorphism (SSCP) fingerprints based on extracted DNA and RNA. The structure and composition of the bacterial core community in the bulk water was highly similar (>70%) across the city of Braunschweig, Germany, whereas all biofilm samples contained a unique community with no overlapping phylotypes from bulk water. Biofilm samples consisted mainly of Alphaproteobacteria (26% of all phylotypes), Gammaproteobacteria (11%), candidate division TM6 (11%), Chlamydiales (9%), and Betaproteobacteria (9%). The bulk water community consisted primarily of Bacteroidetes (25%), Betaproteobacteria (20%), Actinobacteria (16%), and Alphaproteobacteria (11%). All biofilm communities showed higher relative abundances of single phylotypes and a reduced richness compared to bulk water. Only biofilm communities sampled at nearby sampling points showed similar communities irrespective of support materials. In all of our bulk water studies, the community composition determined from 16S rRNA was completely different from the 16S rRNA gene-based community composition, whereas in biofilms both molecular fractions resulted in community compositions that were similar to each other. We hypothesize that a higher fraction of active bacterial phylotypes and a better protection from oxidative stress in drinking water biofilms are responsible for this higher similarity. PMID:22389373

Analysis of structure and composition of bacterial core communities in mature drinking water biofilms and bulk water of a citywide network in Germany.

PubMed

Henne, Karsten; Kahlisch, Leila; Brettar, Ingrid; Höfle, Manfred G

2012-05-01

The bacterial core communities of bulk water and corresponding biofilms of a more than 20-year-old drinking water network were compared using 16S rRNA single-strand confirmation polymorphism (SSCP) fingerprints based on extracted DNA and RNA. The structure and composition of the bacterial core community in the bulk water was highly similar (>70%) across the city of Braunschweig, Germany, whereas all biofilm samples contained a unique community with no overlapping phylotypes from bulk water. Biofilm samples consisted mainly of Alphaproteobacteria (26% of all phylotypes), Gammaproteobacteria (11%), candidate division TM6 (11%), Chlamydiales (9%), and Betaproteobacteria (9%). The bulk water community consisted primarily of Bacteroidetes (25%), Betaproteobacteria (20%), Actinobacteria (16%), and Alphaproteobacteria (11%). All biofilm communities showed higher relative abundances of single phylotypes and a reduced richness compared to bulk water. Only biofilm communities sampled at nearby sampling points showed similar communities irrespective of support materials. In all of our bulk water studies, the community composition determined from 16S rRNA was completely different from the 16S rRNA gene-based community composition, whereas in biofilms both molecular fractions resulted in community compositions that were similar to each other. We hypothesize that a higher fraction of active bacterial phylotypes and a better protection from oxidative stress in drinking water biofilms are responsible for this higher similarity.

Remote detection of widespread indigenous water in lunar pyroclastic deposits

NASA Astrophysics Data System (ADS)

Milliken, Ralph E.; Li, Shuai

2017-08-01

Laboratory analyses of lunar samples provide a direct means to identify indigenous volatiles and have been used to argue for the presence of Earth-like water content in the lunar interior. Some volatile elements, however, have been interpreted as evidence for a bulk lunar mantle that is dry. Here we demonstrate that, for a number of lunar pyroclastic deposits, near-infrared reflectance spectra acquired by the Moon Mineralogy Mapper instrument onboard the Chandrayaan-1 orbiter exhibit absorptions consistent with enhanced OH- and/or H2O-bearing materials. These enhancements suggest a widespread occurrence of water in pyroclastic materials sourced from the deep lunar interior, and thus an indigenous origin. Water abundances of up to 150 ppm are estimated for large pyroclastic deposits, with localized values of about 300 to 400 ppm at potential vent areas. Enhanced water content associated with lunar pyroclastic deposits and the large areal extent, widespread distribution and variable chemistry of these deposits on the lunar surface are consistent with significant water in the bulk lunar mantle. We therefore suggest that water-bearing volcanic glasses from Apollo landing sites are not anomalous, and volatile loss during pyroclastic eruptions may represent a significant pathway for the transport of water to the lunar surface.

Developing a High Fidelity Martian Soil Simulant Based on MSL Measurements: Applications for Habitability, Exploration, and In-Situ Resource Utilization

NASA Astrophysics Data System (ADS)

Cannon, K.; Britt, D. T.; Smith, T. M.; Fritsche, R. F.; Covey, S. D.; Batcheldor, D.; Watson, B.

2017-12-01

Powerful instruments, that include CheMin and SAM on the MSL Curiosity rover, have provided an unprecedented look into the mineral, chemical, and volatile composition of Martian soils. Interestingly, the bulk chemistry of the Rocknest windblown soil is a close match to similar measurements from the Spirit and Opportunity rovers, suggesting the presence of a global basaltic soil component. The Martian regolith is likely composed of this global soil mixed with locally to regionally derived components that include alteration products and evolved volcanic compositions. Without returned soil samples, researchers have relied on terrestrial simulants to address fundamental Mars science, habitability, in-situ resource utilization, and hardware for future exploration. However, these past simulants have low fidelity compared to actual Martian soils: JSC Mars-1a is an amorphous palagonitic material with spectral similarities to Martian dust, not soil, and Mojave Mars is simply a ground up terrestrial basalt chosen for its convenient location. Based on our experience creating asteroid regolith simulants, we are developing a high fidelity Martian soil simulant (Mars Global) designed ab initio to match the mineralogy, chemistry, and volatile contents of the global basaltic soil on Mars. The crystalline portion of the simulant is based on CheMin measurements of Rocknest and includes plagioclase, two pyroxenes, olivine, hematite, magnetite, anhydrite, and quartz. The amorphous portion is less well constrained, but we are re-creating it with basaltic glass, synthetic ferrihydrite, ferric sulfate, and carbonates. We also include perchlorate and nitrate salts based on evolved gas analyses from the SAM instrument. Analysis and testing of Mars Global will include physical properties (shear strength, density, internal friction angle), spectral properties, magnetic properties, and volatile release patterns. The simulant is initially being designed for NASA agricultural studies, but applications include studies of habitability, toxicity, and in-situ resource utilization, among others. Through a partnership with Deep Space Industries we intend to produce industrial quantities of Mars Global from consistently maintained feedstocks, making it available to researchers, engineers, and educators.

CONTROL OF HYDROCARBON EMISSIONS FROM GASOLINE LOADING BY REFRIGERATION SYSTEMS

EPA Science Inventory

The report gives results of a study of the capabilities of refrigeration systems, operated at three temperatures, to control volatile organic compound (VOC) emissions from truck loading at bulk gasoline terminals. Achievable VOC emission rates were calculated for refrigeration sy...

Volatile compounds and phenolic composition of virgin olive oil: optimization of temperature and time of exposure of olive pastes to air contact during the mechanical extraction process.

PubMed

Servili, Maurizio; Selvaggini, Roberto; Taticchi, Agnese; Esposto, Sonia; Montedoro, GianFrancesco

2003-12-31

The operative conditions of malaxation such as temperature and time of exposure of olive pastes to air contact (TEOPAC) affect volatile and phenolic composition of virgin olive oil (VOO) and, as a consequence, its sensory and healthy qualities. In this paper, optimal temperature and TEOPAC during malaxation were studied, in lab scale, in two Italian cultivars using phenolic compounds, volatile composition, and sensory analysis of VOO as markers. The optimal temperature and TEOPAC, selected by response surface modeling,were cultivar-dependent being 30 min of TEOPAC at the lowest temperature investigated (22 degrees C) and 0 min of TEOPAC at 26 degrees C for Frantoio and Moraiolo cultivars, respectively.

Wintertime aerosol chemical composition, volatility, and spatial variability in the greater London area

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, L.; Williams, L. R.; Young, D. E.

The composition of PM 1 (particulate matter with diameter less than 1 µm) in the greater London area was characterized during the Clean Air for London (ClearfLo) project in winter 2012. Two high-resolution time-of-flight aerosol mass spectrometers (HR-ToF-AMS) were deployed at a rural site (Detling, Kent) and an urban site (North Kensington, London). The simultaneous and high-temporal resolution measurements at the two sites provide a unique opportunity to investigate the spatial distribution of PM 1. We find that the organic aerosol (OA) concentration is comparable between the rural and urban sites, but the contribution from different sources is distinctly different between themore » two sites. The concentration of solid fuel OA at the urban site is about twice as high as at the rural site, due to elevated domestic heating in the urban area. While the concentrations of oxygenated OA (OOA) are well-correlated between the two sites, the OOA concentration at the rural site is almost twice that of the urban site. At the rural site, more than 70 % of the carbon in OOA is estimated to be non-fossil, which suggests that OOA is likely related to aged biomass burning considering the small amount of biogenic SOA in winter. Thus, it is possible that the biomass burning OA contributes a larger fraction of ambient OA in wintertime than what previous field studies have suggested. A suite of instruments was deployed downstream of a thermal denuder (TD) to investigate the volatility of PM 1 species at the rural Detling site. After heating at 250 °C in the TD, 40 % of the residual mass is OA, indicating the presence of non-volatile organics in the aerosol. Although the OA associated with refractory black carbon (rBC; measured by a soot-particle aerosol mass spectrometer) only accounts for < 10 % of the total OA (measured by a HR-ToF-AMS) at 250 °C, the two measurements are well-correlated, suggesting that the non-volatile organics have similar sources or have undergone similar chemical processing as rBC in the atmosphere. Although the atomic O : C ratio of OOA is substantially larger than that of solid fuel OA and hydrocarbon-like OA, these three factors have similar volatility, which is inferred from the change in mass concentration after heating at 120 °C. Finally, we discuss the relationship between the mass fraction remaining (MFR) of OA after heating in the TD and atomic O : C of OA and find that particles with a wide range of O : C could have similar MFR after heating. This analysis emphasizes the importance of understanding the distribution of volatility and O : C in bulk OA.« less

Wintertime aerosol chemical composition, volatility, and spatial variability in the greater London area

DOE PAGES

Xu, L.; Williams, L. R.; Young, D. E.; ...

2016-02-02

The composition of PM 1 (particulate matter with diameter less than 1 µm) in the greater London area was characterized during the Clean Air for London (ClearfLo) project in winter 2012. Two high-resolution time-of-flight aerosol mass spectrometers (HR-ToF-AMS) were deployed at a rural site (Detling, Kent) and an urban site (North Kensington, London). The simultaneous and high-temporal resolution measurements at the two sites provide a unique opportunity to investigate the spatial distribution of PM 1. We find that the organic aerosol (OA) concentration is comparable between the rural and urban sites, but the contribution from different sources is distinctly different between themore » two sites. The concentration of solid fuel OA at the urban site is about twice as high as at the rural site, due to elevated domestic heating in the urban area. While the concentrations of oxygenated OA (OOA) are well-correlated between the two sites, the OOA concentration at the rural site is almost twice that of the urban site. At the rural site, more than 70 % of the carbon in OOA is estimated to be non-fossil, which suggests that OOA is likely related to aged biomass burning considering the small amount of biogenic SOA in winter. Thus, it is possible that the biomass burning OA contributes a larger fraction of ambient OA in wintertime than what previous field studies have suggested. A suite of instruments was deployed downstream of a thermal denuder (TD) to investigate the volatility of PM 1 species at the rural Detling site. After heating at 250 °C in the TD, 40 % of the residual mass is OA, indicating the presence of non-volatile organics in the aerosol. Although the OA associated with refractory black carbon (rBC; measured by a soot-particle aerosol mass spectrometer) only accounts for < 10 % of the total OA (measured by a HR-ToF-AMS) at 250 °C, the two measurements are well-correlated, suggesting that the non-volatile organics have similar sources or have undergone similar chemical processing as rBC in the atmosphere. Although the atomic O : C ratio of OOA is substantially larger than that of solid fuel OA and hydrocarbon-like OA, these three factors have similar volatility, which is inferred from the change in mass concentration after heating at 120 °C. Finally, we discuss the relationship between the mass fraction remaining (MFR) of OA after heating in the TD and atomic O : C of OA and find that particles with a wide range of O : C could have similar MFR after heating. This analysis emphasizes the importance of understanding the distribution of volatility and O : C in bulk OA.« less

Trace Element Study of H Chondrites: Evidence for Meteoroid Streams.

NASA Astrophysics Data System (ADS)

Wolf, Stephen Frederic

1993-01-01

Multivariate statistical analyses, both linear discriminant analysis and logistic regression, of the volatile trace elemental concentrations in H4-6 chondrites reveal compositionally distinguishable subpopulations. Observed difference in volatile trace element composition between Antarctic and non-Antarctic H4-6 chondrites (Lipschutz and Samuels, 1991) can be explained by a compositionaily distinct subpopulation found in Victoria Land, Antarctica. This population of H4-6 chondrites is compositionally distinct from non-Antarctic H4-6 chondrites and from Antarctic H4 -6 chondrites from Queen Maud Land. Comparisons of Queen Maud Land H4-6 chondrites with non-Antarctic H4-6 chondrites do not give reason to believe that these two populations are distinguishable from each other on the basis of the ten volatile trace element concentrations measured. ANOVA indicates that these differences are not the result of trivial causes such as weathering and analytical bias. Thermoluminescence properties of these populations parallels the results of volatile trace element comparisons. Given the differences in terrestrial age between Victoria Land, Queen Maud Land, and modern H4-6 chondrite falls, these results are consistent with a variation in H4-6 chondrite flux on a 300 ky timescale. This conclusion requires the existence of co-orbital meteoroid streams. Statistical analyses of the volatile trace elemental concentrations in non-Antarctic modern falls of H4-6 chondrites also demonstrate that a group of 13 H4-6 chondrites, Cluster 1, selected exclusively for their distinct fall parameters (Dodd, 1992) is compositionally distinguishable from a control group of 45 non-Antarctic modern H4-6 chondrites on the basis of the ten volatile trace element concentrations measured. Model-independent randomization-simulations based on both linear discriminant analysis and logistic regression verify these results. While ANOVA identifies two possible causes for this difference, analytical bias and group classification, a test validation experiment verifies that group classification is the more significant cause of compositional difference between Cluster 1 and non-Cluster 1 modern H4-6 chondrite falls. Thermoluminescence properties of these populations parallels the results of volatile trace element comparisons. This suggests that these meteorites are fragments of a co-orbital meteorite stream derived from a single parent body.

Effect of Opalescence(®) bleaching gels on the elution of bulk-fill composite components.

PubMed

Schuster, Lena; Reichl, Franz-Xaver; Rothmund, Lena; He, Xiuli; Yang, Yang; Van Landuyt, Kirsten L; Kehe, Kai; Polydorou, Olga; Hickel, Reinhard; Högg, Christof

2016-02-01

Bleaching treatments can affect release of components from conventional composites. In this continuing study the influence of two different bleaching gels on the elution of bulk-fill composite components was investigated. The composites Tetric EvoCeram(®) Bulk Fill, QuiXFil™ and X-tra fil were treated with the bleaching gels Opalescence PF 15% (PF 15%) for 5 h and PF 35% (PF 35%) for 30 min and then stored in methanol and water for 24 h and 7 d. The eluates were analyzed by gas chromatography/mass spectrometry (GC/MS). Unbleached specimens were used as control group. A total of 7 different elutable substances have been identified from the investigated composites after bleaching-treatment. Three of them were methacrylates: 2-hydroxyethyl methacrylate (HEMA), triethylene glycol dimethacrylate (TEGDMA) and trimethylolpropane trimethacrylate (TMPTMA). Compared to the unbleached controls an increase in elution after PF 15%-treatment of following compounds was found: HEMA (Tetric EvoCeram(®) Bulk Fill), TEGDMA (QuiXFil™, X-tra fil) and 4-N,N-dimethylaminobenzoic acid butyl ethoxy ester (DMABEE) (Tetric EvoCeram(®) Bulk Fill, QuiXFil™, X-tra fil). Following compounds showed a reduction in elution after PF 35%-treatment compared to controls: TEGDMA (QuiXFil™) and DMABEE (Tetric EvoCeram(®) Bulk Fill). The highest concentration of HEMA was 0.22 mmol/l (Tetric EvoCeram(®) Bulk Fill, methanol, 7 d, PF 15%), the highest concentration of TEGDMA was 0.3 mmol/l (X-tra fil, water, 7 d, PF 15%) and the highest concentration of DMABEE was 0.05 mmol/l (QuiXFil™, water, 7 d, PF 35%). PF 15% and PF 35% can lead to reduced and/or increased elution of some bulk-fill components, compared to unbleached bulk-fill composites. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Variation in the chemical composition of cone volatiles within the African cycad genus Encephalartos.

PubMed

Suinyuy, Terence N; Donaldson, John S; Johnson, Steven D

2013-01-01

Volatiles play a key role in attraction of pollinators to cycad cones, but the extent to which volatile chemistry varies among cycad species is still poorly documented. Volatile composition of male and female cones of nineteen African cycad species (Encephalartos; Zamiaceae) was analysed using headspace technique and gas chromatography-mass spectrometry (GC-MS). A total of 152 compounds were identified among the species included in this study, the most common of which were monoterpenes, nitrogen-containing compounds and unsaturated hydrocarbons. Male and female cones emitted similar volatile compounds which varied in relative amounts with two unsaturated hydrocarbons (3E)-1,3-octadiene and (3E,5Z)-1,3,5-octatriene present in the volatile profile of most species. In a multivariate analysis of volatile profiles using non-metric multidimensional scaling (NMDS), a number of species clusters were identified according to shared emission of unsaturated hydrocarbons, pyrazines, benzenoids, aldehydes, alkanes and terpenoids. In comparison, terpenoids are common in Zamia and dominant in Macrozamia species (both in the family Zamiaceae) while benzenoids, esters, and alcohols are dominant in Cycas (Cycadaceae) and in Stangeria (Stangeriaceae). It is likely that volatile variation among Encephalartos species reflects both phylogeny and adaptations to specific beetle pollinators. Copyright © 2012 Elsevier Ltd. All rights reserved.

Isotopically (δ13C and δ18O) heavy volcanic plumes from Central Andean volcanoes: a field study

NASA Astrophysics Data System (ADS)

Schipper, C. Ian; Moussallam, Yves; Curtis, Aaron; Peters, Nial; Barnie, Talfan; Bani, Philipson; Jost, H. J.; Hamilton, Doug; Aiuppa, Alessandro; Tamburello, Giancarlo; Giudice, Gaetano

2017-08-01

Stable isotopes of carbon and oxygen in volcanic gases are key tracers of volatile transfer between Earth's interior and atmosphere. Although important, these data are available for few volcanoes because they have traditionally been difficult to obtain and are usually measured on gas samples collected from fumaroles. We present new field measurements of bulk plume composition and stable isotopes (δ13CCO2 and δ18OH2O+CO2) carried out at three northern Chilean volcanoes using MultiGAS and isotope ratio infrared spectroscopy. Carbon and oxygen in magmatic gas plumes of Lastarria and Isluga volcanoes have δ13C in CO2 of +0.76‰ to +0.77‰ (VPDB), similar to slab carbonate; and δ18O in the H2O + CO2 system ranging from +12.2‰ to +20.7‰ (VSMOW), suggesting significant contributions from altered slab pore water and carbonate. The hydrothermal plume at Tacora has lower δ13CCO2 of -3.2‰ and δ18OH2O+CO2 of +7.0‰, reflecting various scrubbing, kinetic fractionation, and contamination processes. We show the isotopic characterization of volcanic gases in the field to be a practical complement to traditional sampling methods, with the potential to remove sampling bias that is a risk when only a few samples from accessible fumaroles are used to characterize a given volcano's volatile output. Our results indicate that there is a previously unrecognized, relatively heavy isotopic signature to bulk volcanic gas plumes in the Central Andes, which can be attributed to a strong influence from components of the subducting slab, but may also reflect some local crustal contamination. The techniques we describe open new avenues for quantifying the roles that subduction zones and arc volcanoes play in the global carbon cycle.

Characterization and timing of the different types of fluids present in the barren and ore-veins of the W-Sn deposit of Panasqueira, Central Portugal

NASA Astrophysics Data System (ADS)

Noronha, F.; Doria, A.; Dubessy, J.; Charoy, B.

1992-01-01

The Panasqueira W-Sn deposit is the largest quartz-vein type deposit of the Iberian Peninsula and the most important wolframite deposit in Western Europe. The ore-veins are almost exclusively sub-horizontal. Besides ore-bearing sub-horizontal veins, the Panasqueira mine also contains barren quartz veins. There are essentially two generations of barren quartz: quartz, contemporaneous with the earliest regional metamorphism (QI), and recrystallized quartz, contemporaneous with the thermal metamorphism related to the granite intrusion (QII). Fluid inclusion studies (microthermometry and Raman) were undertaken in order to distinguish fluids contemporaneous with the barren quartz from those contemporaneous with the ore-bearing quartz (QIII). Fluid inclusion data indicate that the barren and ore-bearing quartz fluids are dominantly aqueous (93 to 98 mol% H2O), with a nearly constant bulk salinity (8 to 12 wt% eq. NaCl), with the quantity of volatile component (determined by Raman spectrometry) higher in QIII, but never greater than 5 mol%. However, the CO2/CH4 + N2 ratio is different for each type of quartz. Volatiles are dominated by CH4 (10 to 96 mol% ZCH4 and/or N2 (3 to 87 mol% ZN2) in the barren quartz and by CO2 (60 to 73 mol% ZCO2) in ore-bearing quartz. The bulk chemical composition of the fluids in QIII is comparable to that found commonly in hydrothermal fluids associated with wolframite mineralization, where Na>K>Ca and HCO3>Cl>SO4. A dispersion in TH (226 to 350 °C) found in QIII, together with a variation in the degree of filling (0.5 to 0.7) and with the consequent variation of fluid densities (0.70 to 0.79), may result from changes in the fluid pressure regime below lithostatic pressure, suggesting vein filling related to tectonic events.

Bioleached sludge composting drastically reducing ammonia volatilization as well as decreasing bulking agent dosage and improving compost quality: A case study.

PubMed

Hu, Weitong; Zheng, Guanyu; Fang, Di; Cui, Chunhong; Liang, Jianru; Zhou, Lixiang

2015-10-01

Sludge bioleaching technology with Acidithiobacillus species has been commercially adopted for improving advanced dewatering of sludge in China since 2010. However, up to now, little information on bioleached dewatered sludge (BS) composting is available. Here, we report the changes of physicochemical and biological properties in BS composting and evaluate compost product quality compared to conventional dewatered sludge (CS) composting in an engineering scale composting facility. The results showed that the amount of bulking agents required in BS composting was only about 10% of CS composting to obtain optimum moisture content, reducing about 700 kg bulking agents per ton fresh sludge. pH of BS composting mixture was slightly lower consistently by about 0.2-0.3 pH units than that in CS mixture in the first 30 days. Organic matter biodegradation in BS system mainly occurred in the first 9 days of composting. In spite of higher content of NH4(+)-N was found in BS mixture in related to CS mixture; unexpectedly the cumulative ammonia volatilization in the former was only 51% of the latter, indicating that BS composting drastically reduced nitrogen loss. Compared to CS composting system, the relative lower pH, the higher intensity of microbial assimilation, and the presence of water soluble Fe in BS system might jointly reduce ammonia volatilization. Consequently, BS compost product exhibited higher fertilizer values (N+P2O5+K2O=8.38%) as well as lower heavy metal levels due to the solubilization of sludge-borne heavy metals during bioleaching process. Therefore, composting of BS possesses more advantages over the CS composting process. Copyright © 2015 Elsevier Ltd. All rights reserved.

Chondritic Models of 4 Vesta: Comparison of Data from the Dawn Mission with Predicted Internal Structure and Surface Composition/Mineralogy

NASA Technical Reports Server (NTRS)

Toplis, M. J.; Mizzon, H.; Forni, O.; Monnereau, M.; Barrat, J-A.; Prettyman, T. H.; McSween, H. Y.; McCoy, T. J.; Mittlefehldt, D. W.; De Sanctis, M. C.;

Characterization of Crew Refuse Returned from Shuttle Missions with Permanent Gas, Volatile Organic Compound, and Microbial Analyses

NASA Astrophysics Data System (ADS)

Peterson, B.; Hummerick, M.; Roberts, M.; Krummins, V.; Kish, A.; Garland, J.; Maxwell, S.; Mills, A.

In addition to the mass and energy costs associated with bioregenerative systems for advanced life support, the storage and processing of waste on spacecraft requires both atmospheric and biological management. Risks to crew health may arise from the presence of potential human pathogens in waste or from decay processes during waste storage and/or processing. This study reports on the permanent gas, trace volatile organic and microbiological analyses of crew refuse returned from shuttle missions STS-105, 109 and 110. The research objective is to characterize the biological stability of the waste stream, to assess the risks associated with its storage, and to provide baseline measures for the evaluation of waste processing technologies. Microbiological samples were collected from packaging material, food waste, bathroom waste, and bulk liquid collected from the volume F waste container. The number of culturable bacteria and total bacteria were determined by plating on R2A media and by Acridine Orange direct count, respectively. Samples of the trash were analyzed for the presence of fecal and total coliforms and other human-associated bacteria. Dry and ash weights were determined to estimate both water and organic content of the materials. The aerobic and anaerobic bio-stability of stored waste was determined by on-line monitoring of CO2 and by laboratory analysis of off-gas samples for hydrogen sulfide and methane. Volatile organic compounds and permanent gases were analyzed using EPA method TO15 with gas chromatography/mass spectrometry and by gas chromatography with selective detectors . This study establishes a baseline measure of waste composition, labile organics, and microbial load for this material.

Chemical vapor deposition of high T(sub c) superconducting films in a microgravity environment

NASA Technical Reports Server (NTRS)

Levy, Moises; Sarma, Bimal K.

1994-01-01

Since the discovery of the YBaCuO bulk materials in 1987, Metalorganic Chemical Vapor Deposition (MOCVD) has been proposed for preparing HTSC high T(sub c) films. This technique is now capable of producing high-T(sub c) superconducting thin films comparable in quality to those prepared by any other methods. The MOCVD technique has demonstrated its superior advantage in making large area high quality HTSC thin films and will play a major role in the advance of device applications of HTSC thin films. The organometallic precursors used in the MOCVD preparation of HTSC oxide thin films are most frequently metal beta-diketonates. High T(sub c) superconductors are multi-component oxides which require more than one component source, with each source, containing one kind of precursor. Because the volatility and stability of the precursors are strongly dependent on temperature, system pressure, and carrier gas flow rate, it has been difficult to control the gas phase composition, and hence film stoichiometry. In order circumvent these problems we have built and tested a single source MOCVD reactor in which a specially designed vaporizer was employed. This vaporizer can be used to volatilize a stoichiometric mixture of diketonates of yttrium, barium and copper to produce a mixed vapor in a 1:2:3 ratio respectively of the organometellics. This is accomplished even though the three compounds have significantly different volatilities. We have developed a model which provides insight into the process of vaporizing mixed precursors to produce high quality thin films of Y1Ba2Cu3O7. It shows that under steady state conditions the mixed organometallic vapor must have a stoichiometric ratio of the individual organometallics identical to that in the solid mixture.

Materials research for aircraft fire safety

NASA Technical Reports Server (NTRS)

Kourtides, D. A.; Parker, J. A.; Bricker, R. W.

1976-01-01

The thermochemical and flammability characteristics of two polymeric composites currently in use and seven others being considered for use as aircraft interior panels are described. The properties studied included: (1) limiting oxygen index of the composite constituents; (2) fire containment capability of the composite; (3) smoke evolution from the composite; (4) thermogravimetric analysis; (5) composition of the volatile products of thermal degradation; and (6) relative toxicity of the volatile products of pyrolysis. The performance of high-temperature laminating resins such as bismaleimides is compared with the performance of phenolics and epoxies. The relationship of increased fire safety with the use of polymers with high anaerobic char yield is shown. Processing parameters of the state-of-the-art and the advanced bismaleimide composites are detailed.

Juice volatile composition differences between Valencia orange and its mutant Rohde Red Valencia are associated with carotenoid profile differences

USDA-ARS?s Scientific Manuscript database

A targeted approach using HS-SPME-GC–MS was performed to investigate volatile compounds of ordinary Valencia (VAL) and its more deeply colored mutant Rohde Red Valencia orange (RRV) at different developmental stages. Fifty-six volatile components classified into six chemical groups were quantified. ...

Plume composition and volatile flux from Nyamulagira volcano

NASA Astrophysics Data System (ADS)

Calabrese, Sergio; Bobrowski, Nicole; Giuffrida, Giovanni Bruno; Scaglione, Sarah; Liotta, Marcello; Brusca, Lorenzo; D'Alessandro, Walter; Arellano, Santiago; Yalire, Matiew; Galle, Bo; Tedesco, Dario

2015-04-01

Nyamulagira, in the Virunga volcanic province (VVP), Democratic Republic of Congo, is one of the most active volcanoes in Africa. The volcano is located about 25 km north-northwest of Lake Kivu in the Western Branch of the East African Rift System (EARS). The activity is characterized by frequent eruptions (on average, one eruption every 2-4 years) which occur both from the summit crater and from the flanks (31 flank eruptions over the last 110 years). Due to the peculiar low viscosity of its lava and its location in the floor of the rift, Nyamulagira morphology is characterized by a wide lava field that covers over 1100 km2 and contains more than 100 flank cones. Indeed, Nyamulagira is a SiO2- undersaturated and alkali-rich basaltic shield volcano with a 3058 m high summit caldera with an extension of about 2 km in diameter. In November 2014 a field expedition was carried out at Nyamulagira volcano and we report here the first assessment of the plume composition and volatile flux from Nyamulagira volcano. Helicopter flights and field observations allowed us to recognize the presence of lava fountains inside an about 350-meter wide pit crater. The lava fountains originated from an extended area of about 20 to 40 m2, in the northeast sector of the central caldera. A second smaller source, close to the previous described one, was clearly visible with vigorous spattering activity. There was no evidence of a lave lake but the persistence of intense activity and the geometry of the bottom of the caldera might evolve in a new lava lake. Using a variety of in situ and remote sensing techniques, we determined the bulk plume concentrations of major volatiles, halogens and trace elements. We deployed a portable MultiGAS station at the rim of Nyamulagira crater, measuring (at 0.5 Hz for about 3 hours) the concentrations of major volcanogenic gas species in the plume (H2O, CO2, SO2, H2S). Simultaneously, scanning differential optical absorption spectroscopy instruments were applied inside the crater as well as downwind the volcano and active alkaline traps (Raschig-Tube and Drechsel bottle) were exposed. The alkaline solution traps acidic species (CO2, SO2, H2S, HCl, HF, HBr, HI) due to the acid-base reactions. Moreover, filter packs technique have also been used to collect both the volatile phase of the plume (sulphur and halogen species) and the particulate phase (major and trace metals) emitted from the volcano. These new results will add to our lacking knowledge of volcanic degassing in VVP, and will increase constraints on the abundances and origins of volatiles from the mantle source which feeds volcanism in the western branch of the EARS.

Leverage effect and its causality in the Korea composite stock price index

NASA Astrophysics Data System (ADS)

Lee, Chang-Yong

2012-02-01

In this paper, we investigate the leverage effect and its causality in the time series of the Korea Composite Stock Price Index from November of 1997 to September of 2010. The leverage effect, which can be quantitatively expressed as a negative correlation between past return and future volatility, is measured by using the cross-correlation coefficient of different time lags between the two time series of the return and the volatility. We find that past return and future volatility are negatively correlated and that the cross correlation is moderate and decays over 60 trading days. We also carry out a partial correlation analysis in order to confirm that the negative correlation between past return and future volatility is neither an artifact nor influenced by the traded volume. To determine the causality of the leverage effect within the decay time, we additionally estimate the cross correlation between past volatility and future return. With the estimate, we perform a statistical hypothesis test to demonstrate that the causal relation is in favor of the return influencing the volatility rather than the other way around.

Characterisation of volatile compounds produced by bacteria isolated from the spoilage flora of cold-smoked salmon.

PubMed

Joffraud, J J; Leroi, F; Roy, C; Berdagué, J L

2001-06-15

This study investigated the volatile compounds produced by bacteria belonging to nine different bacterial groups: Lactobacillus sake, L. farciminis, L. alimentarius, Carnobacterium piscicola, Aeromonas sp., Shewanella putrefaciens, Brochothrix thermosphacta, Photobacterium phosphoreum and Enterobacteriaceae isolated from cold-smoked salmon. Each bacterial group was represented by several strains. In addition, combinations of the groups were examined as well. Sterile blocks of cold-smoked salmon were inoculated, vacuum-packed and stored at 6 degrees C. After 40 days of storage at 6 degrees C, aerobic viable count and pH were recorded, the volatile fraction of the samples was analysed by gas chromatography-mass spectrometry (GC-MS), and spoilage was assessed by sensory evaluation. Among the 81 volatile compounds identified by GC-MS, 30 appeared to be released as a result of bacterial metabolism. Some of the effects of inoculated bacterial strains on the composition of the volatile fraction seemed to be characteristic of certain bacterial species. Sensory analysis showed relationships between bacteria, the composition of the volatile fraction and the organoleptic quality of smoked salmon.

Ammonia volatilization from a Chinese cabbage field under different nitrogen treatments in the Taihu Lake Basin, China.

PubMed

Shan, Linan; He, Yunfeng; Chen, Jie; Huang, Qian; Wang, Hongcai

2015-12-01

Ammonia (NH3) volatilization is a major pathway of nitrogen (N) loss from soil-crop systems. As vegetable cultivation is one of the most important agricultural land uses worldwide, a deeper understanding of NH3 volatilization is necessary in vegetable production systems. We therefore conducted a 3-year (2010-2012) field experiment to characterize NH3 volatilization and evaluate the effect of different N fertilizer treatments on this process during the growth period of Chinese cabbage. Ammonia volatilization rate, rainfall, soil water content, pH, and soil NH4(+) were measured during the growth period. The results showed that NH3 volatilization was significantly and positively correlated to topsoil pH and NH4(+) concentration. Climate factors and fertilization method also significantly affected NH3 volatilization. Specifically, organic fertilizer (OF) increased NH3 volatilization by 11.77%-18.46%, compared to conventional fertilizer (CF, urea), while organic-inorganic compound fertilizer (OIF) reduced NH3 volatilization by 8.82%-12.67% compared to CF. Furthermore, slow-release fertilizers had significantly positive effects on controlling NH3 volatilization, with a 60.73%-68.80% reduction for sulfur-coated urea (SCU), a 71.85%-78.97% reduction for biological Carbon Power® urea (BCU), and a 77.66%-83.12% reduction for bulk-blend controlled-release fertilizer (BBCRF) relative to CF. This study provides much needed baseline information, which will help in fertilizer choice and management practices to reduce NH3 volatilization and encourage the development of new strategies for vegetable planting. Copyright © 2015. Published by Elsevier B.V.

Fe isotope composition of bulk chondrules from Murchison (CM2): Constraints for parent body alteration, nebula processes and chondrule-matrix complementarity

NASA Astrophysics Data System (ADS)

Hezel, Dominik C.; Wilden, Johanna S.; Becker, Daniel; Steinbach, Sonja; Wombacher, Frank; Harak, Markus

2018-05-01

Chondrules are a major constituent of primitive meteorites. The formation of chondrules is one of the most elusive problems in cosmochemistry. We use Fe isotope compositions of chondrules and bulk chondrites to constrain the conditions of chondrule formation. Iron isotope compositions of bulk chondrules are so far only known from few studies on CV and some ordinary chondrites. We studied 37 chondrules from the CM chondrite Murchison. This is particularly challenging, as CM chondrites contain the smallest chondrules of all chondrite groups, except for CH chondrites. Bulk chondrules have δ56Fe between -0.62 and +0.24‰ relative to the IRMM-014 standard. Bulk Murchison has as all chondrites a δ56Fe of 0.00‰ within error. The δ56Fe distribution of the Murchison chondrule population is continuous and close to normal. The width of the δ56Fe distribution is narrower than that of the Allende chondrule population. Opaque modal abundances in Murchison chondrules is in about 67% of the chondrules close to 0 vol.%, and in 33% typically up to 6.5 vol.%. Chondrule Al/Mg and Fe/Mg ratios are sub-chondritic, while bulk Murchison has chondritic ratios. We suggest that the variable bulk chondrule Fe isotope compositions were established during evaporation and recondensation prior to accretion in the Murchison parent body. This range in isotope composition was likely reduced during aqueous alteration on the parent body. Murchison has a chondritic Fe isotope composition and a number of chondritic element ratios. Chondrules, however, have variable Fe isotope compositions and chondrules and matrix have complementary Al/Mg and Fe/Mg ratios. In combination, this supports the idea that chondrules and matrix formed from a single reservoir and were then accreted in the parent body. The formation in a single region also explains the compositional distribution of the chondrule population in Murchison.

Amplification of seismic waves beneath active volcanoes

NASA Astrophysics Data System (ADS)

Navon, O.; Lensky, N. G.; Collier, L.; Neuberg, J.; Lyakhovsky, V.

2003-04-01

Long-period (LP) seismic events are typical for many volcanoes and are attributed to energy leaking from waves traveling along the conduit - country-rock interface. While the wave propagation is well understood, their actual trigger mechanism and their energy source are not. Here we test the hypothesis that energy may be supplied by volatile-release from a supersaturated melt. If bubbles are initially in equilibrium with the melt in the conduit, and the melt is suddenly decompressed, the transfer of volatiles from the supersaturated melt into the bubbles transforms stored potential energy into expansion work. For example, small dome collapse, opening of a crack or a displacement along the brittle part of the conduit may decompress the magma by a few bars and create the needed supersaturation. This energy is released over the timescale of accelerated expansion, which is longer than a typical LP event. Following decompression, when the transfer of volatiles into bubbles is fast enough, expansion accelerates and the bulk viscosity of the bubbly magma is negative (Lensky et al., 2002). New calculations show that under such conditions a sinusoidal P-wave is amplified. We note that seismic waves created by tectonic earthquakes that are not associated with net decompression, do not lead to net release of volatiles or to net expansion. In this case, the bulk viscosity is positive and waves traveling through the magma should attenuate. The proposed model explains how weak seismic signals may be amplified as they travel through a conduit that contains supersaturated bubbly magma. It provides the general framework for amplifying volcanic seismicity such as long-period events.

Non-CI refractory lithophile abundances in bulk planetary materials

NASA Astrophysics Data System (ADS)

Dauphas, N.

2015-12-01

Refractory inclusions in meteorites show evidence for fractionation of refractory lithophile elements relative to one another. For bulk planetary materials, it is most often assumed that refractory lithophile elements (e.g., Ca, Al, Ti, REEs) are in proportions similar to CI carbonaceous chondrites, which is taken to be a proxy for solar composition. A diagnostic feature of REE patterns in refractory inclusions in meteorites is the presence of thulium anomalies, arising from the fact that this heavy REE is more volatile than the highly refractory HREEs surrounding it (Tm/Tm* is defined relative to either Er-Yb or Er-Lu). Tm anomalies thus represent an excellent diagnostic tool to test the assumption that refractory lithophile elements have uniform relative abundances at a bulk planetary scale. Prior to this work, high precision Tm measurements were lacking because it is mono-isotopic and as such is not amenable to high-precision single spike measurements. We have developed a multi-collector REE abundance measurement technique to measure all REEs at high precision, including the mono-isotopic ones. This technique was used to revise the abundance of CI and PAAS REE abundances (Pourmand et al. 2012) and the CI composition agrees well with an independent study (Barrat et al. 2012). The same technique was applied to measure REE patterns in 41 chondrites as well as terrestrial rocks (Dauphas and Pourmand, 2015). Our results reveal the presence of Tm anomalies of about -4.5 % in terrestrial rocks, enstatite and ordinary chondrites, relative to carbonaceous chondrites including CIs. This demonstrates that the assumption that refractory lithophile elements are in constant proportions among planetary bodies is unwarranted. It also shows that carbonaceous chondrites cannot be a major constituent of the Earth. The presence of Tm anomalies in meteorites and terrestrial rocks suggests that either (i) the material in the inner part of the solar system was formed from a gas reservoir that had been depleted in refractory dust or (ii) CI are enriched in refractory dust and are not representative of solar composition for refractory elements. Barrat J.A. et al. (2012) GCA 83, 79-92. Dauphas N., Pourmand A. (2015) GCA 163, 234-261. Pourmand et al. (2012) Chem. Geol. 291, 38-54.

Apatite: A New Tool For Understanding The Temporal Variability Of Magmatic Volatile Contents

NASA Astrophysics Data System (ADS)

Stock, M. J.; Humphreys, M.; Smith, V.; Pyle, D. M.; Isaia, R.

2015-12-01

The apatite crystal structure is capable of incorporating H2O, F and Cl, as well as trace CO2 and sulphur. These can be related to parental magma compositions through application of a series of pressure and temperature-dependent exchange reactions (Piccoli and Candela, 1994), permitting apatite crystals to preserve a record of all major volatile species in the melt. Furthermore, due to the general incompatibility of P in other rock-forming minerals, apatite is ubiquitous in igneous systems and often begins crystallising early, such that apatite inclusions within phenocrysts record melt volatile contents throughout magmatic differentiation. In this work, we compare the compositions of apatite inclusions and microphenocrysts with pyroxene-hosted melt inclusions from the Astroni 1 eruption of Campi Flegrei, Italy. These data are coupled with magmatic differentiation models (Gualda et al., 2012), experimental volatile solubility data (Webster et al., 2014) and thermodynamic models of apatite compositional variations (Piccoli and Candela, 1994) to determine a time-series of magmatic volatile evolution in the build-up to eruption. We find that apatite halogen/OH ratios decreased through magmatic differentiation, while melt inclusion F and Cl concentrations increased. Melt inclusion H2O contents are constant at ~2.5 wt%. These data are best explained by volatile-undersaturated differentiation over most of the crystallisation history of the Astroni 1 melt, with melt inclusion H2O contents reset during ascent, due to rapid H diffusion through the phenocryst hosts (Woods et al., 2000). Given the rapid diffusivity of volatiles in apatite (Brenan, 1993), preservation of undersaturated compositions in microphenocrysts suggests that saturation was only achieved a few days to months before eruption and that it may have been the transition into a volatile-saturated state that ultimately triggered eruption. Piccoli and Candela, 1994. Am. J. of Sc., 294, 92-135. Gualda et al., 2012. J. Pet., 53, 875-890. Webster et al., 2014. J. Pet., 55, 2217-2248. Woods et al., 2000. Am. Min., 85, 480-487. Brenan, 1993. Chem. Geol., 110, 195-210.

Aromatherapy: composition of the gaseous phase at equilibrium with liquid bergamot essential oil.

PubMed

Leggio, Antonella; Leotta, Vanessa; Belsito, Emilia Lucia; Di Gioia, Maria Luisa; Romio, Emanuela; Santoro, Ilaria; Taverna, Domenico; Sindona, Giovanni; Liguori, Angelo

2017-11-02

This work compares the composition at different temperatures of gaseous phase of bergamot essential oil at equilibrium with the liquid phase. A new GC-MS methodology to determine quantitatively the volatile aroma compounds was developed. The adopted methodology involved the direct injection of headspace gas into injection port of GC-MS system and of known amounts of the corresponding authentic volatile compounds. The methodology was validated. This study showed that gaseous phase composition is different from that of the liquid phase at equilibrium with it.

Crystal Growth of II-VI Semiconducting Alloys by Directional Solidification

NASA Technical Reports Server (NTRS)

Lehoczky, Sandor L.; Szofran, Frank R.; Su, Ching-Hua; Cobb, Sharon D.; Scripa, Rosalia A.; Sha, Yi-Gao

1999-01-01

This research study is investigating the effects of a microgravity environment during the crystal growth of selected II-VI semiconducting alloys on their compositional, metallurgical, electrical and optical properties. The on-going work includes both Bridgman-Stockbarger and solvent growth methods, as well as growth in a magnetic field. The materials investigated are II-VI, Hg(1-x)Zn(x)Te, and Hg(1-x)Zn(x)Se, where x is between 0 and 1 inclusive, with particular emphasis on x-values appropriate for infrared detection and imaging in the 5 to 30 micron wavelength region. Wide separation between the liquidus and solidus of the phase diagrams with consequent segregation during solidification and problems associated with the high volatility of one of the components (Hg), make the preparation of homogeneous, high-quality, bulk crystals of the alloys an extremely difficult nearly an impossible task in a gravitational environment. The three-fold objectives of the on-going investigation are as follows: (1) To determine the relative contributions of gravitationally-driven fluid flows to the compositional redistribution observed during the unidirectional crystal growth of selected semiconducting solid solution alloys having large separation between the liquidus and solidus of the constitutional phase diagram; (2) To ascertain the potential role of irregular fluid flows and hydrostatic pressure effects in generation of extended crystal defects and second-phase inclusions in the crystals; and, (3) To obtain a limited amount of "high quality" materials needed for bulk crystal property characterizations and for the fabrication of various device structures needed to establish ultimate material performance limits. The flight portion of the study was to be accomplished by performing growth experiments using the Crystal Growth Furnace (CGF) manifested to fly on various Spacelab missions.

Depth of cure of bulk-fill flowable composite resins.

PubMed

Pedalino, Inaam; Hartup, Grant R; Vandewalle, Kraig S

2015-01-01

In recent years, manufacturers have introduced flowable composite resins that reportedly can be placed in increments of 4 mm or greater. The purpose of this study was to evaluate the depth of cure of bulk-fill flowable composite resins (SureFil SDR Flow, Grandio Flow, and Venus Bulk Fill) and a conventional flowable composite resin (Revolution Formula 2). Depth of cure was measured in terms of bottom-maximum Knoop hardness number (KHN) ratios and the International Organization for Standardization (ISO) 4049 scrape technique. Shades A2 and A3 of SureFil SDR Flow, Grandio Flow, and Revolution Formula 2 were tested. Venus Bulk Fill was tested in its only available shade (universal). Specimens in thicknesses of 2, 3, 4, 5, and 6 mm were polymerized for 20 or 40 seconds, and a hardness tester was used to determine the hardness ratios for each shade at each thickness. For the scraping technique, after specimens were exposed to the curing light, unpolymerized composite resin was removed with a plastic instrument, the polymerized composite was measured, and the length was divided by 2 per ISO guidelines. According to the KHN ratios and the scrape test, Venus Bulk Fill predictably exceeded the manufacturer's claim of a 4-mm depth of cure at both 20 and 40 seconds of curing time. The overall results for depth of cure showed that Venus Bulk Fill ≥ SureFil SDR Flow ≥ Grandio Flow ≥ Revolution Formula 2.

Effect of dual-cure composite resin as restorative material on marginal adaptation of class 2 restorations.

PubMed

Bortolotto, Tissiana; Melian, Karla; Krejci, Ivo

2013-10-01

The present study attempted to find a simple direct adhesive restorative technique for the restoration of Class 2 cavities. A self-etch adhesive system with a dual-cured core buildup composite resin (paste 1 + paste 2) was evaluated in its ability to restore proximo-occlusal cavities with margins located on enamel and dentin. The groups were: A, cavity filling (cf) with paste 1 (light-curing component) by using a layering technique; B, cf by mixing both pastes, bulk insertion, and dual curing; and C, cf by mixing both pastes, bulk insertion, and chemical curing. Two control groups (D, negative, bulk; and E, positive, layering technique) were included by restoring cavities with a classic three-step etch-and-rinse adhesive and a universal restorative composite resin. SEM margin analysis was performed before and after thermomechanical loading in a chewing simulator. Percentages (mean ± SD) of "continuous margins" were improved by applying the material in bulk and letting it self cure (54 ± 6) or dual cure (59 ± 9), and no significant differences were observed between these two groups and the positive control (44 ± 19). The present study showed that the dual-cured composite resin tested has the potential to be used as bulk filling material for Class 2 restorations. When used as filling materials, dual-cure composite resins placed in bulk can provide marginal adaptation similar to light-cured composites applied with a complex stratification technique.

[Composition of the electrocautery smoke: integrative literature review].

PubMed

Tramontini, Cibele Cristina; Galvão, Cristina Maria; Claudio, Caroline Vieira; Ribeiro, Renata Perfeito; Martins, Júlia Trevisan

2016-02-01

To identify the composition of the smoke produced by electrocautery use during surgery. Integrative review with search for primary studies conducted in the databases of the US National Library of Medicine National Institutes of Health, Cumulative Index to Nursing and Allied Health Literature, and Latin American and Caribbean Health Sciences, covering the studies published between 2004 and 2014. The final sample consisted of 14 studies grouped into three categories, namely; polycyclic aromatic hydrocarbons, volatile compounds and volatile organic compounds. There is scientific evidence that electrocautery smoke has volatile toxic, carcinogenic and mutagenic compounds, and its inhalation constitutes a potential chemical risk to the health of workers involved in surgeries.

Effects of high pressure processing on fatty acid composition and volatile compounds in Korean native black goat meat.

PubMed

Kang, Geunho; Cho, Soohyun; Seong, Pilnam; Park, Beomyoung; Kim, Sangwoo; Kim, Donghun; Kim, Youngjun; Kang, Sunmun; Park, Kyoungmi

2013-08-01

This study investigated the effects of high pressure processing (HPP) on fatty acid composition and volatile compounds in Korean native black goat (KNBG) meat. Fatty acid content in KNBG meat was not significantly (p > 0.05) different among the control goats and those subjected HPP. The 9,12-octadecadienoic acid and octadecanoic acid, well-known causes of off-flavors, were detected from meat of some KNBG. A difference between the control and HPP treatment was observed in the discriminated function analysis using an electronic nose. The results suggest that the volatile compounds in KNBG meat were affected by HPP.

Pinot noir wine volatile and anthocyanin composition under different levels of vine fruit zone leaf removal.

PubMed

Feng, Hui; Skinkis, Patricia A; Qian, Michael C

2017-01-01

The impacts of fruit zone leaf removal on volatile and anthocyanin compositions of Pinot noir wine were investigated over two growing seasons. Wine volatiles were analyzed by multiple techniques, including headspace solid phase microextraction-GC-MS (HS-SPME-GC-MS), headspace-GC-FID (HS-GC-FID) and stir bar sorptive extraction-GC-MS (SBSE-GC-MS). Fruit zone leaf removal affected the concentration of many grape-derived volatile compounds such as terpene alcohols and C13-norisoprenoids in wine, although the degree of impact depended on the vintage year and severity of leaf removal. Fruit zone leaf removal resulted in greater concentrations of linalool, α-terpineol and β-damascenone but had no impact on other terpene alcohols or β-ionone. Fruit zone leaf removal had no consistent impact on C6 alcohols, volatile phenols, lactones, fermentation-derived alcohols, acids, or most esters. Fruit zone leaf removal increased anthocyanins in final wine. Copyright © 2016 Elsevier Ltd. All rights reserved.

Trichomes and chemical composition of the volatile oil of Trichogonia cinerea (Gardner) R. M. King & H. Rob. (Eupatorieae, Asteraceae).

PubMed

Fernandes, Yanne S; Trindade, Luma M P; Rezende, Maria Helena; Paula, José R; Gonçalves, Letícia A

2016-03-01

Trichogonia cinerea is endemic to Brazil and occurs in areas of cerrado and campo rupestre. In this study, we characterized the glandular and non-glandular trichomes on the aerial parts of this species, determined the principal events in the development of the former, and identified the main constituents of the volatile oil produced in its aerial organs. Fully expanded leaves, internodes, florets, involucral bracts, and stem apices were used for the characterization of trichomes. Leaves, internodes, florets, and involucral bracts were examined by light microscopy and scanning electron microscopy, whereas stem apices were examined only by light microscopy. Branches in the reproductive phase were used for the extraction and determination of the composition of the volatile oil. The species has three types of glandular trichomes, biseriate vesicular, biseriate pedunculate, and multicellular uniseriate, which secrete volatile oils and phenolic compounds. The major components identified in the volatile oil were 3,5-muuroladiene (39.56%) and butylated hydroxytoluene (13.07%).

Forecasting volatility of SSEC in Chinese stock market using multifractal analysis

NASA Astrophysics Data System (ADS)

Wei, Yu; Wang, Peng

2008-03-01

In this paper, taking about 7 years’ high-frequency data of the Shanghai Stock Exchange Composite Index (SSEC) as an example, we propose a daily volatility measure based on the multifractal spectrum of the high-frequency price variability within a trading day. An ARFIMA model is used to depict the dynamics of this multifractal volatility (MFV) measures. The one-day ahead volatility forecasting performances of the MFV model and some other existing volatility models, such as the realized volatility model, stochastic volatility model and GARCH, are evaluated by the superior prediction ability (SPA) test. The empirical results show that under several loss functions, the MFV model obtains the best forecasting accuracy.

Formation and aging of secondary organic aerosol from toluene: Changes in chemical composition, volatility, and hygroscopicity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hildebrandt Ruiz, L.; Paciga, A. L.; Cerully, K. M.

Secondary organic aerosol (SOA) is transformed after its initial formation, but this chemical aging of SOA is poorly understood. Experiments were conducted in the Carnegie Mellon environmental chamber to form secondary organic aerosol (SOA) from the photo-oxidation of toluene and other small aromatic volatile organic compounds (VOCs) in the presence of NO x under different oxidizing conditions. The effects of the oxidizing condition on organic aerosol (OA) composition, mass yield, volatility, and hygroscopicity were explored. Higher exposure to the hydroxyl radical resulted in different OA composition, average carbon oxidation state (OS c), and mass yield. The OA oxidation state generallymore » increased during photo-oxidation, and the final OA OS c ranged from –0.29 to 0.16 in the performed experiments. The volatility of OA formed in these different experiments varied by as much as a factor of 30, demonstrating that the OA formed under different oxidizing conditions can have a significantly different saturation concentration. In conclusion, there was no clear correlation between hygroscopicity and oxidation state for this relatively hygroscopic SOA.« less

Formation and aging of secondary organic aerosol from toluene: Changes in chemical composition, volatility, and hygroscopicity

DOE PAGES

Hildebrandt Ruiz, L.; Paciga, A. L.; Cerully, K. M.; ...

2015-07-24

Secondary organic aerosol (SOA) is transformed after its initial formation, but this chemical aging of SOA is poorly understood. Experiments were conducted in the Carnegie Mellon environmental chamber to form secondary organic aerosol (SOA) from the photo-oxidation of toluene and other small aromatic volatile organic compounds (VOCs) in the presence of NO x under different oxidizing conditions. The effects of the oxidizing condition on organic aerosol (OA) composition, mass yield, volatility, and hygroscopicity were explored. Higher exposure to the hydroxyl radical resulted in different OA composition, average carbon oxidation state (OS c), and mass yield. The OA oxidation state generallymore » increased during photo-oxidation, and the final OA OS c ranged from –0.29 to 0.16 in the performed experiments. The volatility of OA formed in these different experiments varied by as much as a factor of 30, demonstrating that the OA formed under different oxidizing conditions can have a significantly different saturation concentration. In conclusion, there was no clear correlation between hygroscopicity and oxidation state for this relatively hygroscopic SOA.« less

Depth of cure of resin composites: is the ISO 4049 method suitable for bulk fill materials?

PubMed

Flury, Simon; Hayoz, Stefanie; Peutzfeldt, Anne; Hüsler, Jürg; Lussi, Adrian

2012-05-01

To evaluate if depth of cure D(ISO) determined by the ISO 4049 method is accurately reflected with bulk fill materials when compared to depth of cure D(new) determined by Vickers microhardness profiles. D(ISO) was determined according to "ISO 4049; Depth of cure" and resin composite specimens (n=6 per group) were prepared of two control materials (Filtek Supreme Plus, Filtek Silorane) and four bulk fill materials (Surefil SDR, Venus Bulk Fill, Quixfil, Tetric EvoCeram Bulk Fill) and light-cured for either 10s or 20s. For D(new), a mold was filled with one of the six resin composites and light-cured for either 10 s or 20 s (n=22 per group). The mold was placed under a microhardness indentation device and hardness measurements (Vickers hardness, VHN) were made at defined distances, beginning at the resin composite that had been closest to the light-curing unit (i.e. at the "top") and proceeding toward the uncured resin composite (i.e. toward the "bottom"). On the basis of the VHN measurements, Vickers hardness profiles were generated for each group. D(ISO) varied between 1.76 and 6.49 mm with the bulk fill materials showing the highest D(ISO). D(new) varied between 0.2 and 4.0 mm. D(new) was smaller than D(ISO) for all resin composites except Filtek Silorane. For bulk fill materials the ISO 4049 method overestimated depth of cure compared to depth of cure determined by Vickers hardness profiles. Copyright © 2012 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Dynamic mechanical properties of a Ti-based metallic glass matrix composite

NASA Astrophysics Data System (ADS)

Li, Jinshan; Cui, Jing; Qiao, Jichao; Bai, Jie; Kou, Hongchao; Wang, Jun

2015-04-01

Dynamic mechanical behavior of a Ti50Zr20Nb12Cu5Be13 bulk metallic glass composite was investigated using mechanical spectroscopy in both temperature and frequency domains. Storage modulus G' and loss modulus G″ are determined by temperature, and three distinct regions corresponding to different states in the bulk metallic glass composite are characterized. Physical parameters, such as atomic mobility and correlation factor χ, are introduced to analyze dynamic mechanical behavior of the bulk metallic glass composite in the framework of quasi-point defects (QPD) model. The experimental results are in good agreement with the prediction of QPD model.

Dynamic mechanical properties of a Ti-based metallic glass matrix composite

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Jinshan, E-mail: ljsh@nwpu.edu.cn; Cui, Jing; Bai, Jie

2015-04-21

Dynamic mechanical behavior of a Ti{sub 50}Zr{sub 20}Nb{sub 12}Cu{sub 5}Be{sub 13} bulk metallic glass composite was investigated using mechanical spectroscopy in both temperature and frequency domains. Storage modulus G′ and loss modulus G″ are determined by temperature, and three distinct regions corresponding to different states in the bulk metallic glass composite are characterized. Physical parameters, such as atomic mobility and correlation factor χ, are introduced to analyze dynamic mechanical behavior of the bulk metallic glass composite in the framework of quasi-point defects (QPD) model. The experimental results are in good agreement with the prediction of QPD model.

Lipase-catalyzed modification of the flavor profiles in recombined skim milk products by enriching the volatile components.

PubMed

Zhang, X M; Ai, N S; Wang, J; Tong, L J; Zheng, F P; Sun, B G

2016-11-01

The purpose of this study was to modify the amount and composition of volatile components in bovine milk products, in an attempt to create a recombined skim milk product with full-fat milk flavor but with only 0.5% fat. The experimental plan included lipase-catalyzed hydrolysis and esterification reactions using Palatase 20000L (Novozymes, Bagsværd, Denmark). The results, measured by the methods of volatile compositional analysis and sensory evaluation, showed that the flavor profiles of the optimal recombined milk products were effectively modified in this way, possessing intensified characteristic volatile flavor components with rather low level of fat contents, and the sensory characters were quite realistic to natural whole milk flavor. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Pluto's Global Surface Composition Through Pixel-by-Pixel Hapke Modeling of New Horizons Ralph LEISA Data

NASA Technical Reports Server (NTRS)

Protopapa, S.; Grundy, W. M.; Reuter, D. C.; Hamilton, D. P.; Dalle Ore, C. M.; Cook, J. C.; Cruikshank, D. P.; Schmitt, B.; Philippe, S.; Quirico, E.;

Pluto's global surface composition through pixel-by-pixel Hapke modeling of New Horizons Ralph/LEISA data

NASA Astrophysics Data System (ADS)

Protopapa, S.; Grundy, W. M.; Reuter, D. C.; Hamilton, D. P.; Dalle Ore, C. M.; Cook, J. C.; Cruikshank, D. P.; Schmitt, B.; Philippe, S.; Quirico, E.; Binzel, R. P.; Earle, A. M.; Ennico, K.; Howett, C. J. A.; Lunsford, A. W.; Olkin, C. B.; Parker, A.; Singer, K. N.; Stern, A.; Verbiscer, A. J.; Weaver, H. A.; Young, L. A.; New Horizons Science Team

2017-05-01

On July 14th 2015, NASA's New Horizons mission gave us an unprecedented detailed view of the Pluto system. The complex compositional diversity of Pluto's encounter hemisphere was revealed by the Ralph/LEISA infrared spectrometer on board of New Horizons. We present compositional maps of Pluto defining the spatial distribution of the abundance and textural properties of the volatiles methane and nitrogen ices and non-volatiles water ice and tholin. These results are obtained by applying a pixel-by-pixel Hapke radiative transfer model to the LEISA scans. Our analysis focuses mainly on the large scale latitudinal variations of methane and nitrogen ices and aims at setting observational constraints to volatile transport models. Specifically, we find three latitudinal bands: the first, enriched in methane, extends from the pole to 55°N, the second dominated by nitrogen, continues south to 35°N, and the third, composed again mainly of methane, reaches 20°N. We demonstrate that the distribution of volatiles across these surface units can be explained by differences in insolation over the past few decades. The latitudinal pattern is broken by Sputnik Planitia, a large reservoir of volatiles, with nitrogen playing the most important role. The physical properties of methane and nitrogen in this region are suggestive of the presence of a cold trap or possible volatile stratification. Furthermore our modeling results point to a possible sublimation transport of nitrogen from the northwest edge of Sputnik Planitia toward the south.

Pattern recognition and genetic algorithms for discrimination of orange juices and reduction of significant components from headspace solid-phase microextraction.

PubMed

Rinaldi, Maurizio; Gindro, Roberto; Barbeni, Massimo; Allegrone, Gianna

2009-01-01

Orange (Citrus sinensis L.) juice comprises a complex mixture of volatile components that are difficult to identify and quantify. Classification and discrimination of the varieties on the basis of the volatile composition could help to guarantee the quality of a juice and to detect possible adulteration of the product. To provide information on the amounts of volatile constituents in fresh-squeezed juices from four orange cultivars and to establish suitable discrimination rules to differentiate orange juices using new chemometric approaches. Fresh juices of four orange cultivars were analysed by headspace solid-phase microextraction (HS-SPME) coupled with GC-MS. Principal component analysis, linear discriminant analysis and heuristic methods, such as neural networks, allowed clustering of the data from HS-SPME analysis while genetic algorithms addressed the problem of data reduction. To check the quality of the results the chemometric techniques were also evaluated on a sample. Thirty volatile compounds were identified by HS-SPME and GC-MS analyses and their relative amounts calculated. Differences in composition of orange juice volatile components were observed. The chosen orange cultivars could be discriminated using neural networks, genetic relocation algorithms and linear discriminant analysis. Genetic algorithms applied to the data were also able to detect the most significant compounds. SPME is a useful technique to investigate orange juice volatile composition and a flexible chemometric approach is able to correctly separate the juices.

Hierarchical Analytical Approaches for Unraveling the Composition of Proprietary Mixtures

EPA Pesticide Factsheets

The composition of commercial mixtures including pesticide inert ingredients, aircraft deicers, and aqueous film-forming foam (AFFF) formulations, and by analogy, fracking fluids, are proprietary. Quantitative analytical methodologies can only be developed for mixture components once their identities are known. Because proprietary mixtures may contain volatile and non-volatile components, a hierarchy of analytical methods is often required for the full identification of all proprietary mixture components.

Petrology of a nonindigenous microgranitic clast in polymict ureilite EET 87720: Evidence for formation of evolved melt on an unknown parent body

NASA Astrophysics Data System (ADS)

Beard, A. D.; Downes, H.; Chaussidon, M.

2015-09-01

EET 87720 is a polymict ureilite breccia known to contain numerous nonindigenous fragments. We have discovered a microgranitic clast in an interior chip of Elephant Moraine (EET) 87720. The clast consists of a granophyre-like intergrowth of a pure SiO2 phase (tridymite) and albite, mantling a zoned oligoclase phenocryst. In the intergrowth, the tridymite occurs as thin elongate vermicular blebs within larger albite crystals. The granophyre-like intergrowth and the oligoclase phenocryst share a common margin, suggesting that the clast was originally part of a larger fragment. An estimate of its bulk composition is equivalent to that of granite (77 wt% SiO2). Patches of high-Si K-bearing glass occur interstitially within the clast; they have high concentrations of SO3 (11-12 wt%) and contain Cl (0.6 wt%), suggesting that the clast formed on a volatile-rich parent body perhaps resembling early Mars. The mean oxygen isotope composition of the feldspar and tridymite in the clast is very different from the oxygen isotope compositions of ureilites, and is similar to those of silicate inclusions in IIE and IVA irons. Thus, the clast is not indigenous to the ureilite parent body, but it provides evidence for the formation of evolved melts on an unknown parent body in the early solar system.

Evaluating Changes In the Elemental Composition of Micrometeorites During Entry into the Earth’s Atmosphere

NASA Astrophysics Data System (ADS)

Rudraswami, N. G.; Shyam Prasad, M.; Dey, S.; Plane, J. M. C.; Feng, W.; Taylor, S.

2015-11-01

We evaluate the heating of extraterrestrial particles entering the atmosphere using the comprehensive chemical ablation model (CABMOD). This model predicts the ablation rates of individual elements in a particle with a defined size, composition, entry velocity, and entry angle with respect to the zenith (ZA). In the present study, bulk chemical analyses of 1133 Antarctica micrometeorites (collected from the south pole water well) are interpreted using CABMOD. The marked spread in Fe/Si values in unmelted, partially melted, and melted micrometeorites is explained by the loss of relatively volatile Fe during atmospheric entry. The combined theoretical modeling and elemental composition of the micrometeorites (Mg/Si ratios) suggest that ˜85% of particles have a provenance of carbonaceous chondrites, the remaining ˜15% are either ordinary or enstatite chondrites. About 65% of the micrometeorites have undergone <20% ablation, while a further 20% have lost between 20% and 60% of their original mass. This has implications for understanding the micrometeorite flux that reaches the Earth's surface, as well as estimating the pre-atmospheric size of the particles. Our work shows that the unmelted particles that contribute ˜50% to the total micrometeorite collection on Earth's surface have a small entry zone: ZA = 60°-90° if the entry velocity is ˜11 km s-1, and ZA = 80°-90° for >11-21 km s-1.

Geochemical constraints on volatile sources and subsurface conditions at Mount Martin, Mount Mageik, and Trident Volcanoes, Katmai Volcanic Cluster, Alaska

NASA Astrophysics Data System (ADS)

Lopez, T.; Tassi, F.; Aiuppa, A.; Galle, B.; Rizzo, A. L.; Fiebig, J.; Capecchiacci, F.; Giudice, G.; Caliro, S.; Tamburello, G.

2017-11-01

We use the chemical and isotopic composition of volcanic gases and steam condensate, in situ measurements of plume composition and remote measurements of SO2 flux to constrain volatile sources and characterize subvolcanic conditions at three persistently degassing and seismically active volcanoes within the Katmai Volcanic Cluster (KVC), Alaska: Mount Martin, Mount Mageik and Trident. In situ plume measurements of gas composition were collected at all three volcanoes using MultiGAS instruments to calculate gas ratios (e.g. CO2/H2S, SO2/H2S and H2O/H2S), and remote measurements of SO2 column density were collected from Mount Martin and Mount Mageik by ultraviolet spectrometer systems to calculate SO2 fluxes. Fumaroles were directly sampled for chemical and isotopic composition from Mount Mageik and Trident. Mid Ocean Ridge Basalt (MORB)-like 3He/4He ratios ( 7.2-7.6 Rc/RA) within Mount Mageik and Trident's fumarole emissions and a moderate SO2 flux ( 75 t/d) from Mount Martin, combined with gas compositions dominated by H2O, CO2 and H2S from all three volcanoes, indicate magma degassing and active hydrothermal systems in the subsurface of these volcanoes. Mount Martin's gas emissions have the lowest CO2/H2S ratio ( 2-4) and highest SO2 flux compared to the other KVC volcanoes, indicative of shallow magma degassing. Geothermometry techniques applied to Mount Mageik and Trident's fumarolic gas compositions suggest that their hydrothermal reservoirs are located at depths of 0.2 and 4 km below the surface, respectively. Observations of an unusually reducing gas composition at Trident and organic material in the near-surface soils suggest that thermal decomposition of sediments may be influencing gas composition. When the measured gas compositions from Mount Mageik and Trident are compared with previous samples collected in the late 1990's, relatively stable magmatic-hydrothermal conditions are inferred for Mount Mageik, while gradual degassing of residual magma and contamination by shallow crustal fluids is inferred for Trident. The isotopic composition of volcanic gases emitted from Mount Mageik and Trident reflect mixing of subducted slab, mantle and crustal volatile sources, with organic sediment and carbonate being the predominant sources. Considering the close proximity of the target volcanoes in comparison with the depth to the subducted slab we speculate that Aleutian Arc volatiles are fed by a relatively homogeneous subducted fluid and that much of the apparent variability in volatile provenance can be explained by shallow crustal volatile sources and/or processes.

[Comparison of wear resistance and flexural strength of three kinds of bulk-fill composite resins].

PubMed

Zhang, Huan; Zhang, Meng-Long; Qiu, Li-Hong; Yu, Jing-Tao; Zhan, Fu-Liang

2016-06-01

To compare the abrasion resistance and flexure strength of three bulk-fill resin composites with an universal nano-hybrid composite resins. The specimens were prepared with three kinds of bulk fill composites (SDR , sonicfill, Tetric N-Ceram Bulk Fill) and an universal nano-hybrid composite resins(Herculite Precis). 10 mm in diameter × 2mm in height specimens were prepared for abrasion resistance, while 2 mm in width × 2 mm in depth×25 mm in length specimens were prepared for flexure strength. The specimens were mounted in a bal1-on-disc wear testing machine and abraded with the media artificial saliva(50 N loads, 10000 cycles).Flexural test was performed with an Universal Testing Machine at a cross-head speed of 1mm/min. One-way variance analysis was used to determine the statistical differences of volume loss and flexural strength among groups with SPSS 13.0 software package(P<0.05). The volume loss was as follows: SDR (1.2433±0.11) mm30.05). With regard to wear resistance and flexural strength, Tetric N-Ceram Bulk Fill is recommended as an alternative for posterior restorations.

Post-irradiation hardness development, chemical softening, and thermal stability of bulk-fill and conventional resin-composites.

PubMed

Alshali, Ruwaida Z; Salim, Nesreen A; Satterthwaite, Julian D; Silikas, Nick

2015-02-01

To measure bottom/top hardness ratio of bulk-fill and conventional resin-composite materials, and to assess hardness changes after dry and ethanol storage. Filler content and kinetics of thermal decomposition were also tested using thermogravimetric analysis (TGA). Six bulk-fill (SureFil SDR, Venus bulk fill, X-tra base, Filtek bulk fill flowable, Sonic fill, and Tetric EvoCeram bulk-fill) and eight conventional resin-composite materials (Grandioso flow, Venus Diamond flow, X-flow, Filtek Supreme Ultra Flowable, Grandioso, Venus Diamond, TPH Spectrum, and Filtek Z250) were tested (n=5). Initial and 24h (post-cure dry storage) top and bottom microhardness values were measured. Microhardness was re-measured after the samples were stored in 75% ethanol/water solution. Thermal decomposition and filler content were assessed by TGA. Results were analysed using one-way ANOVA and paired sample t-test (α=0.05). All materials showed significant increase of microhardness after 24h of dry storage which ranged from 100.1% to 9.1%. Bottom/top microhardness ratio >0.9 was exhibited by all materials. All materials showed significant decrease of microhardness after 24h of storage in 75% ethanol/water which ranged from 14.5% to 74.2%. The extent of post-irradiation hardness development was positively correlated to the extent of ethanol softening (R(2)=0.89, p<0.001). Initial thermal decomposition temperature assessed by TGA was variable and was correlated to ethanol softening. Bulk-fill resin-composites exhibit comparable bottom/top hardness ratio to conventional materials at recommended manufacturer thickness. Hardness was affected to a variable extent by storage with variable inorganic filler content and initial thermal decomposition shown by TGA. The manufacturer recommended depth of cure of bulk-fill resin-composites can be reached based on the microhardness method. Characterization of the primary polymer network of a resin-composite material should be considered when evaluating its stability in the aqueous oral environment. Copyright © 2014 Elsevier Ltd. All rights reserved.

Scientific results of the NASA-sponsored study project on Mars: Evolution of volcanism, tectonics, and volatiles

NASA Technical Reports Server (NTRS)

Solomon, Sean C. (Editor); Sharpton, Virgil L. (Editor); Zimbelman, James R. (Editor)

1990-01-01

The objectives of the Mars: Evolution of Volcanism, Tectonics, and Volatiles (MEVTV) project are to outline the volcanic and tectonic history of Mars; to determine the influence of volatiles on Martian volcanic and tectonic processes; and to attempt to determine the compositional, thermal, and volatile history of Mars from its volcanic and tectonic evolution. Available data sets were used to test general models of the volcanic and tectonic history of Mars.

Heating-Induced Evaporation of Nine Different Secondary Organic Aerosol Types

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kolesar, Katheryn R.; Li, Ziyue; Wilson, Kevin R.

The volatility of the compounds comprising organic aerosol (OA) determines their distribution between the gas and particle phases. However, there is a disconnect between volatility distributions as typically derived from secondary OA (SOA) growth experiments and the effective particle volatility as probed in evaporation experiments. Specifically, the evaporation experiments indicate an overall much less volatile SOA. This raises questions regarding the use of traditional volatility distributions in the simulation and prediction of atmospheric SOA concentrations. Here, we present results from measurements of thermally induced evaporation of SOA for nine different SOA types (i.e., distinct volatile organic compound and oxidant pairs)more » encompassing both anthropogenic and biogenic compounds and O 3 and OH to examine the extent to which the low effective volatility of SOA is a general phenomenon or specific to a subset of SOA types. The observed extents of evaporation with temperature were similar for all the SOA types and indicative of a low effective volatility. Furthermore, minimal variations in the composition of all the SOA types upon heating-induced evaporation were observed. These results suggest that oligomer decomposition likely plays a major role in controlling SOA evaporation, and since the SOA formation time scale in these measurements was less than a minute, the oligomer-forming reactions must be similarly rapid. Overall, these results emphasize the importance of accounting for the role of condensed phase reactions in altering the composition of SOA when assessing particle volatility.« less

Heating-Induced Evaporation of Nine Different Secondary Organic Aerosol Types

DOE PAGES

Kolesar, Katheryn R.; Li, Ziyue; Wilson, Kevin R.; ...

2015-09-22

The volatility of the compounds comprising organic aerosol (OA) determines their distribution between the gas and particle phases. However, there is a disconnect between volatility distributions as typically derived from secondary OA (SOA) growth experiments and the effective particle volatility as probed in evaporation experiments. Specifically, the evaporation experiments indicate an overall much less volatile SOA. This raises questions regarding the use of traditional volatility distributions in the simulation and prediction of atmospheric SOA concentrations. Here, we present results from measurements of thermally induced evaporation of SOA for nine different SOA types (i.e., distinct volatile organic compound and oxidant pairs)more » encompassing both anthropogenic and biogenic compounds and O 3 and OH to examine the extent to which the low effective volatility of SOA is a general phenomenon or specific to a subset of SOA types. The observed extents of evaporation with temperature were similar for all the SOA types and indicative of a low effective volatility. Furthermore, minimal variations in the composition of all the SOA types upon heating-induced evaporation were observed. These results suggest that oligomer decomposition likely plays a major role in controlling SOA evaporation, and since the SOA formation time scale in these measurements was less than a minute, the oligomer-forming reactions must be similarly rapid. Overall, these results emphasize the importance of accounting for the role of condensed phase reactions in altering the composition of SOA when assessing particle volatility.« less

The bulk composition of Titan's atmosphere.

NASA Technical Reports Server (NTRS)

Trafton, L.

1972-01-01

Consideration of the physical constraints for Titan's atmosphere leads to a model which describes the bulk composition of the atmosphere in terms of observable parameters. Intermediate-resolution photometric scans of both Saturn and Titan, including scans of the Q branch of Titan's methane band, constrain these parameters in such a way that the model indicates the presence of another important atmospheric gas, namely, another bulk constituent or a significant thermal opacity. Further progress in determining the composition and state of Titan's atmosphere requires additional observations to eliminate present ambiguities. For this purpose, particular observational targets are suggested.

Compositional heterogeneity of the Sugarloaf melilite nephelinite flow, Honolulu Volcanics, Hawai'i

NASA Astrophysics Data System (ADS)

Clague, David A.; Frey, Frederick A.; Garcia, Michael O.; Huang, Shichun; McWilliams, Michael; Beeson, Melvin H.

2016-07-01

The Sugarloaf flow is a melilite nephelinite erupted from the Tantalus rift during rejuvenated-stage volcanism on O'ahu, the Honolulu Volcanics. The flow ponded in Mānoa Valley forming a ∼15 m thick flow which was cored and sampled in a quarry. Nepheline from a pegmatoid segregation in the flow yielded a 40Ar-39Ar age of 76 ka. This age, combined with others, indicates that the Tantalus rift eruptions are some of the youngest on O'ahu. Honolulu Volcanics erupt on average about every 35-40 ka indicating that future eruptions are possible. We evaluated the compositional variability of 19 samples from the flow, including 14 from the core. Twelve samples are representative of the bulk flow, four are dark- or light-colored variants, one is a heavy rare earth element (REE)-enriched pegmatoid, and two visually resemble the bulk flow, but have chemical characteristics of the dark and light variants. Our objective was to determine intraflow heterogeneity in mineralogy and composition. Variable abundances of Na2O, K2O, Sr, Ba, Rb, Pb and U in the flow were caused by post-eruptive mobility in a vapor phase, most likely during or soon after flow emplacement, and heterogeneous deposition of secondary calcite and zeolites. Relative to fine-grained samples, a pegmatoid vein that crosscuts the flow is enriched in incompatible trace elements except Sr and TiO2. Element mobility after eruption introduced scatter in trace element ratios including light-REE/heavy-REE, and all ratios involving mobile elements K, Rb, Ba, Sr, Pb, and U. Lavas from some of the 37 Honolulu Volcanics vents have crosscutting REE patterns in a primitive mantle-normalized plot. Such patterns have been interpreted to reflect variable amounts of residual garnet during partial melting. Previous studies of lavas from different vents concluded that garnet, phlogopite, amphibole, and Fe-Ti oxides were residual phases of the partial melting processes that created the Honolulu Volcanics (Clague and Frey, 1982; Yang et al., 2003). However post-eruptive processes in the Sugarloaf flow also produced crossing REE patterns. Eruptions on the Tantalus rift, including the Sugarloaf flow, produced volatile- and crystal-rich ash with interstitial glass and melt inclusions in olivine containing 4.2-6.4 wt% MgO compared to the flow average of 11.8 wt%. This flow erupted as a partially crystallized viscous magma at least 100 °C below its liquidus. The slow advance and cooling of the 15-m thick 'a' ā low promoted the segregation of pegmatoids, formation of light and dark bands with differing proportions of melilite and clinopyroxene, and induced volatile-enhanced mobility of incompatible elements.

Comparative study of volatile oil content and antimicrobial activity of pecan cultivars growing in Egypt.

PubMed

El Hawary, Seham S; Zaghloul, Soumaya S; El Halawany, Ali M; El Bishbishy, Mahitab H

2013-11-01

The volatile oils obtained from the leaves of four pecan cultivars growing in Egypt were evaluated for their chemical composition and antimicrobial activity. The selected cultivars (cv.) were Carya illinoinensis (Wangneh.) K. Koch. cv. Wichita, C. illinoinensis cv. Western Schley, C. illinoinensis cv. Cherokee, and C. illinoinensis cv. Sioux. The gas chromatography-mass spectrometry analyses revealed that the volatile oils from samples of the different cultivars differ in composition and percentage of their components. β-Curcumene was found as the major constituent of the cv. Wichita oil, whereas germacrene D was the major component of cv. Sioux, cv. Cherokee, and cv. Western Schley. The antimicrobial activity was assayed using the Kirby-Bauer Method by measuring the zone of inhibition of growth. All volatile oils displayed an antimicrobial activity against the tested bacterial strains. On the other hand, only the volatile oil of cv. Wichita showed an antifungal effect on Aspergillus flavus. This work has identified candidates of volatile oils for future in vivo studies to develop antibiotic substitutes for the diminution of human and animal pathogenic bacteria. Nevertheless, the variations of the volatile oil components and antimicrobial potencies of the different studied cultivars, necessitate identifying the cultivars used in future studies.

A model for the compositions of non-stoichiometric intermediate phases formed by diffusion reactions, and its application to Nb 3Sn superconductors

DOE PAGES

Xu, X.; Sumption, M. D.

2016-01-12

In this work we explore the compositions of non-stoichiometric intermediate phases formed by diffusion reactions: a mathematical framework is developed and tested against the specific case of Nb 3Sn superconductors. In the first part, the governing equations for the bulk diffusion and interphase interface reactions during the growth of a compound are derived, numerical solutions to which give both the composition profile and growth rate of the compound layer. The analytic solutions are obtained with certain approximations made. In the second part, we explain an effect that the composition characteristics of compounds can be quite different depending on whether itmore » is the bulk diffusion or grain boundary diffusion that dominates in the compounds, and that “frozen” bulk diffusion leads to unique composition characteristics that the bulk composition of a compound layer remains unchanged after its initial formation instead of varying with the diffusion reaction system; here the model is modified for the case of grain boundary diffusion. Lastly, we apply this model to the Nb 3Sn superconductors and propose approaches to control their compositions.« less

Relationships between volatile compounds and sensory characteristics in virgin olive oil by analytical and chemometric approaches.

PubMed

Procida, Giuseppe; Cichelli, Angelo; Lagazio, Corrado; Conte, Lanfranco S

2016-01-15

The volatile fraction of virgin olive oil is characterised by low molecular weight compounds that vaporise at room temperature. In order to obtain an aroma profile similar to natural olfactory perception, the composition of the volatile compounds was determined by applying dynamic headspace gas chromatography, performed at room temperature, with a cryogenic trap directly connected to a gas chromatograph-mass spectrometer system. Samples were also evaluated according to European Union and International Olive Council official methods for sensory evaluation. In this paper, the composition of the volatile fraction of 25 extra virgin olive oils from different regions of Italy was analysed and some preliminary considerations on relationships between chemical composition of volatile fraction and sensory characteristics are reported. Forty-two compounds were identified by means of the particular analytical technique used. All the analysed samples, classified as extra virgin by the panel test, never present peaks whose magnitude is important enough in defected oils. The study was focused on the evaluation of volatile compounds responsible for the positive impact on olive odour properties ('green-fruity' and 'sweet') and olfactory perception. Chemometric evaluation of data, obtained through headspace analysis and the panel test evaluation, showed a correlation between chemical compounds and sensory properties. On the basis of the results, the positive attributes of virgin olive oil are divided into two separated groups: sweet types or green types. Sixteen volatile compounds with known positive impact on odour properties were extracted and identified. In particular, eight compounds seem correlated with sweet properties whereas the green sensation appears to be correlated with eight other different substances. The content of the compounds at six carbon atoms proves to be very important in defining positive attributes of extra virgin olive oils and sensory evaluation. © 2015 Society of Chemical Industry.

FINAL REPORT: Room Temperature Hydrogen Storage in Nano-Confined Liquids

DOE Office of Scientific and Technical Information (OSTI.GOV)

VAJO, JOHN

2014-06-12

DOE continues to seek solid-state hydrogen storage materials with hydrogen densities of ≥6 wt% and ≥50 g/L that can deliver hydrogen and be recharged at room temperature and moderate pressures enabling widespread use in transportation applications. Meanwhile, development including vehicle engineering and delivery infrastructure continues for compressed-gas hydrogen storage systems. Although compressed gas storage avoids the materials-based issues associated with solid-state storage, achieving acceptable volumetric densities has been a persistent challenge. This project examined the possibility of developing storage materials that would be compatible with compressed gas storage technology based on enhanced hydrogen solubility in nano-confined liquid solvents. These materialsmore » would store hydrogen in molecular form eliminating many limitations of current solid-state materials while increasing the volumetric capacity of compressed hydrogen storage vessels. Experimental methods were developed to study hydrogen solubility in nano-confined liquids. These methods included 1) fabrication of composites comprised of volatile liquid solvents for hydrogen confined within the nano-sized pore volume of nanoporous scaffolds and 2) measuring the hydrogen uptake capacity of these composites without altering the composite composition. The hydrogen storage capacities of these nano-confined solvent/scaffold composites were compared with bulk solvents and with empty scaffolds. The solvents and scaffolds were varied to optimize the enhancement in hydrogen solubility that accompanies confinement of the solvent. In addition, computational simulations were performed to study the molecular-scale structure of liquid solvent when confined within an atomically realistic nano-sized pore of a model scaffold. Confined solvent was compared with similar simulations of bulk solvent. The results from the simulations were used to formulate a mechanism for the enhanced solubility and to guide the experiments. Overall, the combined experimental measurements and simulations indicate that hydrogen storage based on enhanced solubility in nano-confined liquids is unlikely to meet the storage densities required for practical use. Only low gravimetric capacities of < 0.5 wt% were achieved. More importantly, solvent filled scaffolds had lower volumetric capacities than corresponding empty scaffolds. Nevertheless, several of the composites measured did show significant (>~ 5x) enhanced hydrogen solubility relative to bulk solvent solubility, when the hydrogen capacity was attributed only to dissolution in the confined solvent. However, when the hydrogen capacity was compared to an empty scaffold that is known to store hydrogen by surface adsorption on the scaffold walls, including the solvent always reduced the hydrogen capacity. For the best composites, this reduction relative to an empty scaffold was ~30%; for the worst it was ~90%. The highest capacities were obtained with the largest solvent molecules and with scaffolds containing 3- dimensionally confined pore geometries. The simulations suggested that the capacity of the composites originated from hydrogen adsorption on the scaffold pore walls at sites not occupied by solvent molecules. Although liquid solvent filled the pores, not all of the adsorption sites on the pore walls were occupied due to restricted motion of the solvent molecules within the confined pore space.« less

Isotopically enriched ammonium shows high nitrogen transformation in the pile top zone of dairy manure compost

NASA Astrophysics Data System (ADS)

Maeda, Koki; Toyoda, Sakae; Yano, Midori; Hattori, Shohei; Fukasawa, Makoto; Nakajima, Keiichi; Yoshida, Naohiro

2016-03-01

Nitrogen isotope ratios (δ15N) of NH4+ in dairy manure compost piles with and without bulking agent (10 % w/w) were compared to understand the effects of the use of bulking agent on nitrogen conversion during manure composting. The δ15N-NH4+ values in each of three pile zones (top, side and core) were also compared. At the end of the process, piles with bulking agent showed significantly higher δ15N values (17.7 ± 1.3 ‰) than piles without bulking agent (11.8 ± 0.9 ‰), reflecting the significantly higher nitrogen conversion and NH3 loss in the former. The samples from the top zone, especially in the piles with bulking agent, showed very high NH4+ concentrations with significantly high 15N (δ15N: 12.7-29.8 ‰) values, indicating that extremely high nitrogen conversion, nitrification-denitrification activity of the microbes and NH3 volatilization occurred in this zone.

A survey of biofilms on wastewater aeration diffusers suggests bacterial community composition and function vary by substrate type and time.

PubMed

Noble, Peter A; Park, Hee-Deung; Olson, Betty H; Asvapathanagul, Pitiporn; Hunter, M Colby; Garrido-Baserba, Manel; Lee, Sang-Hoon; Rosso, Diego

2016-07-01

Aeration diffusers in wastewater treatment plants generate air bubbles that promote mixing, distribution of dissolved oxygen, and microbial processing of dissolved and suspended matter in bulk solution. Biofouling of diffusers represents a significant problem to wastewater treatment plants because biofilms decrease oxygen transfer efficiency and increase backpressure on the blower. To better understand biofouling, we conducted a pilot study to survey the bacterial community composition and function of biofilms on different diffuser substrates and compare them to those in the bulk solution. DNA was extracted from the surface of ethylene-propylene-diene monomer (EPDM), polyurethane, and silicone diffusers operated for 15 months in a municipal treatment plant and sampled at 3 and 9 months. The bacterial community composition and function of the biofilms and bulk solution were determined by amplifying the 16S rRNA genes and pyrosequencing the amplicons and raw metagenomic DNA. The ordination plots and dendrograms of the 16S rRNA and functional genes showed that while the bacterial community composition and function of the bulk solution was independent of sampling time, the composition and function of the biofilms differed by diffuser type and testing time. For the EPDM and silicone diffusers, the biofilm communities were more similar in composition to the bulk solution at 3 months than 9 months. In contrast, the bacteria on the polyurethane diffusers were more dissimilar to the bulk solution at 3 months than 9 months. Taken together, the survey showed that the community composition and function of bacterial biofilms depend on the diffuser substrate and testing time, which warrants further elucidation.

U, Th, and K in planetary cores: Implications for volatile elements and heat production

NASA Astrophysics Data System (ADS)

Boujibar, A.; Habermann, M.; Righter, K.; Ross, D. K.; Righter, M.; Chidester, B.; Rapp, J. F.; Danielson, L. R.; Pando, K.; Andreasen, R.

2016-12-01

The accretion of terrestrial planets is known to be accompanied with volatile loss due to strong solar winds produced by the young Sun and due to energetic impacts. It was previously expected that Mercury, the innermost planet is depleted in volatile elements in comparison to other terrestrial planets. These predictions have been recently challenged by the MESSENGER mission to Mercury that detected relatively high K/U and K/Th ratios on Mercury's surface, suggesting a volatile content similar to Earth and Mars. However previous studies showed that Fe-rich metals can incorporate substantial U, Th and K under reducing conditions and with high sulfur contents, which are two conditions relevant to Mercury. In order to quantify the fractionation of these heat-producing elements during core segregation, we determined experimentally their partition coefficients (Dmet/sil) between metal and silicate at varying pressure, temperature, oxygen fugacity and sulfur content. Our data confirm that U, Th, and K become more siderophile with decreasing fO2 and increasing sulfur content, with a stronger effect for U and Th in comparison to K. Hence Mercury's core is likely to have incorporated more U and Th than K, resulting in the elevated K/U and K/Th ratios measured on the surface. The bulk concentrations of U, Th, and K in terrestrial planets (Mercury, Venus, Earth and Mars) are calculated based on geochemical constraints on core-mantle differentiation. Significant amounts of U, Th and K are partitioned into the cores of Mercury, Venus and Earth, but much less into Mars' core. The resulting bulk planet K/U and K/Th correlate with the heliocentric distance, which suggests an overall volatile depletion in the inner Solar System. These results have important implications for internal heat production. The role of impact erosion on the evolution of Th/U ratio will also be addressed.

Thermoelectric properties of SrTiO3 nano-particles dispersed indium selenide bulk composites

NASA Astrophysics Data System (ADS)

Lee, Min Ho; Rhyee, Jong-Soo; Vaseem, Mohammad; Hahn, Yoon-Bong; Park, Su-Dong; Jin Kim, Hee; Kim, Sung-Jin; Lee, Hyeung Jin; Kim, Chilsung

2013-06-01

We investigated the thermoelectric properties of the InSe, InSe/In4Se3 composite, and SrTiO3 (STO) nano-particles dispersed InSe/In4Se3 bulk composites. The electrical conductivity of the InSe/In4Se3 composite with self-assembled phase separation is significantly increased compared with those of InSe and In4Se3-δ implying the enhancement of surface conductivity between grain boundaries. The thermal conductivity of InSe/In4Se3 composite is decreased compared to those of InSe. When the STO nano-particle dispersion was employed in the InSe/In4Se3 composite, a coherent interface was observed between nano-particle precipitates and the InSe bulk matrix with a reduction of the thermal conductivity.

Signal or noise? Separating grain size-dependent Nd isotope variability from provenance shifts in Indus delta sediments, Pakistan

NASA Astrophysics Data System (ADS)

Jonell, T. N.; Li, Y.; Blusztajn, J.; Giosan, L.; Clift, P. D.

2017-12-01

Rare earth element (REE) radioisotope systems, such as neodymium (Nd), have been traditionally used as powerful tracers of source provenance, chemical weathering intensity, and sedimentary processes over geologic timescales. More recently, the effects of physical fractionation (hydraulic sorting) of sediments during transport have called into question the utility of Nd isotopes as a provenance tool. Is source terrane Nd provenance resolvable if sediment transport strongly induces noise? Can grain-size sorting effects be quantified? This study works to address such questions by utilizing grain size analysis, trace element geochemistry, and Nd isotope geochemistry of bulk and grain-size fractions (<63μm, 63-125 μm, 125-250 μm) from the Indus delta of Pakistan. Here we evaluate how grain size effects drive Nd isotope variability and further resolve the total uncertainties associated with Nd isotope compositions of bulk sediments. Results from the Indus delta indicate bulk sediment ɛNd compositions are most similar to the <63 µm fraction as a result of strong mineralogical control on bulk compositions by silt- to clay-sized monazite and/or allanite. Replicate analyses determine that the best reproducibility (± 0.15 ɛNd points) is observed in the 125-250 µm fraction. The bulk and finest fractions display the worst reproducibility (±0.3 ɛNd points). Standard deviations (2σ) indicate that bulk sediment uncertainties are no more than ±1.0 ɛNd points. This argues that excursions of ≥1.0 ɛNd points in any bulk Indus delta sediments must in part reflect an external shift in provenance irrespective of sample composition, grain size, and grain size distribution. Sample standard deviations (2s) estimate that any terrigenous bulk sediment composition should vary no greater than ±1.1 ɛNd points if provenance remains constant. Findings from this study indicate that although there are grain-size dependent Nd isotope effects, they are minimal in the Indus delta such that resolvable provenance-driven trends can be identified in bulk sediment ɛNd compositions over the last 20 k.y., and that overall provenance trends remain consistent with previous findings.

Polymerization Behavior and Mechanical Properties of High-Viscosity Bulk Fill and Low Shrinkage Resin Composites.

PubMed

Shibasaki, S; Takamizawa, T; Nojiri, K; Imai, A; Tsujimoto, A; Endo, H; Suzuki, S; Suda, S; Barkmeier, W W; Latta, M A; Miyazaki, M

The present study determined the mechanical properties and volumetric polymerization shrinkage of different categories of resin composite. Three high viscosity bulk fill resin composites were tested: Tetric EvoCeram Bulk Fill (TB, Ivoclar Vivadent), Filtek Bulk Fill posterior restorative (FB, 3M ESPE), and Sonic Fill (SF, Kerr Corp). Two low-shrinkage resin composites, Kalore (KL, GC Corp) and Filtek LS Posterior (LS, 3M ESPE), were used. Three conventional resin composites, Herculite Ultra (HU, Kerr Corp), Estelite ∑ Quick (EQ, Tokuyama Dental), and Filtek Supreme Ultra (SU, 3M ESPE), were used as comparison materials. Following ISO Specification 4049, six specimens for each resin composite were used to determine flexural strength, elastic modulus, and resilience. Volumetric polymerization shrinkage was determined using a water-filled dilatometer. Data were evaluated using analysis of variance followed by Tukey's honestly significant difference test (α=0.05). The flexural strength of the resin composites ranged from 115.4 to 148.1 MPa, the elastic modulus ranged from 5.6 to 13.4 GPa, and the resilience ranged from 0.70 to 1.0 MJ/m 3 . There were significant differences in flexural properties between the materials but no clear outliers. Volumetric changes as a function of time over a duration of 180 seconds depended on the type of resin composite. However, for all the resin composites, apart from LS, volumetric shrinkage began soon after the start of light irradiation, and a rapid decrease in volume during light irradiation followed by a slower decrease was observed. The low shrinkage resin composites KL and LS showed significantly lower volumetric shrinkage than the other tested materials at the measuring point of 180 seconds. In contrast, the three bulk fill resin composites showed higher volumetric change than the other resin composites. The findings from this study provide clinicians with valuable information regarding the mechanical properties and polymerization kinetics of these categories of current resin composite.

A review of the contrasting behavior of two magmatic volatiles: Chlorine and carbon dioxide

USGS Publications Warehouse

Lowenstern, J. B.

2000-01-01

Chlorine (Cl) and carbon dioxide (CO2) are common magmatic volatiles with contrasting behaviors. CO2 solubility increases with pressure whereas Cl solubility shows relatively little pressure or temperature effect. CO2 speciation changes with silicate melt composition, dissolving as carbonate in basaltic magmas and molecular CO2 in more silicic compositions. In H2O-bearing systems, the strongly non-ideal behavior of alkali chlorides causes unmixing of the volatile phase to form a H2O-rich vapor and a hydrosaline phase with important implications for the maximum concentration of Cl in magmas. Addition of CO2 to magma hastens immiscibility at crustal pressures (<500 MPa), inducing the formation of CO2-rich vapors and Cl-rich hydrosaline melts. (C) 2000 Elsevier Science B.V. All rights reserved.Chlorine (Cl) and carbon dioxide (CO2) are common magmatic volatiles with contrasting behaviors. CO2 solubility increases with pressure whereas Cl solubility shows relatively little pressure or temperature effect. CO2 speciation changes with silicate melt composition, dissolving as carbonate in basaltic magmas and molecular CO2 in more silicic compositions. In H2O-bearing systems, the strongly non-ideal behavior of alkali chlorides causes unmixing of the volatile phase to form a H2O-rich vapor and a hydrosaline phase with important implications for the maximum concentration of Cl in magmas. Addition of CO2 to magma hastens immiscibility at crustal pressures (<500 MPa), inducing the formation of CO2-rich vapors and Cl-rich hydrosaline melts.

Topographic and Other Influences on Pluto's Volatile Ices

NASA Astrophysics Data System (ADS)

Lewis, Briley Lynn; Stansberry, John; Grundy, William M.; Schmitt, Bernard; Protopapa, Silvia; Trafton, Laurence M.; Holler, Bryan J.; McKinnon, William B.; Schenk, Paul M.; Stern, S. Alan; Young, Leslie; Weaver, Harold A.; Olkin, Catherine; Ennico, Kimberly; New Horizons Science Team, The New Horizons Composition Team

2018-01-01

Pluto’s surface is known to consist of various volatile ices, mostly N2, CH4, and CO, which sublimate and condense on varying timescales, generally moving from points of high insolation to those of low insolation. The New Horizons Pluto encounter data provide multiple lenses through which to view Pluto’s detailed surface topography and composition and to investigate the distribution of volatiles on its surface, including albedo and elevation maps from the imaging instruments and composition maps from the LEISA spectral imager. The volatile surface ice is expected to be generally isothermal, due to the fact that their vapor pressures are in equilibrium with the atmosphere. Although secular topographic transport mechanisms suggest that points at low elevation should slowly fill with volatile ices (Trafton 2015 DPS abstract, Bertrand and Forget 2017), there are counter-examples of this across the surface, implying that energy discrepancies caused by insolation differences, albedo variations, local slopes, and other effects may take precedence at shorter timescales. Using data from the 2015 New Horizons flyby, we present our results of this investigation into the effects of variations in insolation, albedo, and topography on the presence of the different volatile ices across the surface of Pluto.

Topographic and Other Influences on Pluto's Volatile Ices

NASA Astrophysics Data System (ADS)

Lewis, Briley Lynn; Stansberry, John; Grundy, William M.; Schmitt, Bernard; Protopapa, Silvia; Trafton, Laurence M.; Holler, Bryan J.; McKinnon, William B.; Schenk, Paul M.; Stern, S. Alan; Young, Leslie; Weaver, Harold A.; Olkin, Catherine; Ennico, Kimberly; New Horizons Science Team

2017-10-01

Pluto’s surface is known to consist of various volatile ices, mostly N2, CH4, and CO, which sublimate and condense on varying timescales, generally moving from points of high insolation to those of low insolation. The New Horizons Pluto encounter data provide multiple lenses through which to view Pluto’s detailed surface topography and composition and to investigate the distribution of volatiles on its surface, including albedo and elevation maps from the imaging instruments and composition maps from the LEISA spectral imager. The volatile surface ice is expected to be generally isothermal, due to the fact that their vapor pressures are in equilibrium with the atmosphere. Although secular topographic transport mechanisms suggest that points at low elevation should slowly fill with volatile ices (Trafton 2015 DPS abstract, Bertrand and Forget 2017), there are counter-examples of this across the surface, implying that energy discrepancies caused by insolation differences, albedo variations, local slopes, and other effects may take precedence at shorter timescales. Using data from the 2015 New Horizons flyby, we present our results of this investigation into the effects of variations in insolation, albedo, and topography on the presence of the different volatile ices across the surface of Pluto.

Variable mixing and degassing of mantle CO2 within continental subsurface water bodies evidenced by compared gas geochemistry and fluid-phase equilibrium modeling

NASA Astrophysics Data System (ADS)

Virgile, R.

2016-12-01

The continental degassing of mantle volatiles is known from a variety of areas characterized by Asthenosphere updoming, such as the US Basin and Range and the European Cenozoic Rift System. Mantle degassing is there usually associated to magmatic provinces where non-volcanic upwellings of cold to hot waters are frequently associated with high CO2 gas loads. The resulting aquifers, springs and mofets express variable gas compositions which are often attributed to the mixing of crustal and mantle CO2, and less often to the variable degassing states of the waters. Indeed, the compositions of water and gas in CO2, δ13C and the noble gases may justify both models. However, the implications of each model for the bulk degassing mass quantification of mantle volatiles are drastically different, and would therefore need to be confirmed or rejected on a case by case basis. We introduce here a new model for predicting fluid phase equilibrium for systems comprising CO2-CH4-H2-H2S-N2-O2-He-Ne-Ar-Kr-Xe-H2O-NaCl at shallow subsurface conditions (1-250 bars, 0-150°C). The model was applied in P-T conditions comparable to non-volcanic CO2 degassing systems, where initial fluids were defined as variable mixtures of air equilibrated water (AEW) and mantle volatiles (CO2, He, CO2/3He = 5 x109). Literature data from European non-volcanic mantle degassing systems were compiled and compared to different modeling scenarios. The distribution of the CO2/3He (from 108 to 1012) and N2/3He (from 106 to 1011) ratios in natural samples are consistent with the open system degassing of initial fluids at depths above 2000m, with variable recharges of AEW. Initial single phase fluids are composed of up to 300 mol.m-3 CO2, 7 x10-3 mol.m-3 He and N2 with typical AEW contents (0.5 mol.m-3). Most degassed systems correspond to 98% degassed initial fluids, which incorporated up to 10% of fresh AEW subsequently to degassing. Our results suggest that fluid phase fractionation effects alone are sufficient to generate the range of compositions observed in the studied natural water-gas systems, without the need to invoke a crustal CO2 end-member.

Impact glasses from the ultrafine fraction of lunar soils

NASA Technical Reports Server (NTRS)

Norris, J. A.; Keller, L. P.; Mckay, D. S.

1993-01-01

The chemical compositions of microscopic glasses produced during meteoroid impacts on the lunar surface provide information regarding the various fractionation processes which accompany these events. To learn more about these fractionation processes, we studied the compositions of submicrometer glass spheres from two Apollo 17 sampling sites using electron microscopy. The majority of the analyzed glasses show evidence for varying degrees of impact induced chemical fractionation. Among these are HASP glasses (High-Al, Si-Poor) which are believed to represent the refractory residuum left after the loss of volatile elements (e.g. Si, Fe, N) from the precursor material. In addition to HASP-type glasses, we also observed a group of VRAP glasses (volatile-rich, Al-poor) that represent condensates of vaporized volatile constituents and are complementary to the HASP compositions. High-Ti glasses were also found during the course of the study, and are documented here for the first time.

The multimodal magnetoelectric effect in the ring-shaped magnetostrictive-piezoelectric bulk composites

NASA Astrophysics Data System (ADS)

Radchenko, G. S.; Filippov, D. A.; Laletin, V. M.

2015-11-01

The theoretical and experimental investigation of the direct magnetoelectric effect in the ring-type structures made of the bulk magnetostrictive-piezoelectric composites has been presented. The analytical expression for the magnetoelectric voltage coefficient has been obtained using the effective parameters method. The frequency dependence of this parameter is also analyzed. The dependence of the resonant frequency and the amplitude of this effect of the geometrical parameters of the ring for the first and second oscillation modes are presented. The experimental investigation of the direct magnetoelectric effect for the ring-type composite specimens consisting of the nickel ferrite spinel-PZT bulk composite is done. The obtained experimental data are in good agreement with the theoretical predictions.

[Research on the combustion mechanism of asphalt and the composition of harmful gas based on infrared spectral analysis].

PubMed

Wu, Ke; Zhu, Kai; Huang, Zhi-yi; Wang, Jin-chang; Yang, Qin-min; Liang, Pei

2012-08-01

By using the Rosemount gas analyzer and the test platform of fixed bed built by carbon furnace, the harmful gaseous compositions and the release rules of asphalt and mortar under high temperature rate were analyzed quantitatively based on infrared spectral analysis technology. The results indicated that the combustion process of the asphalt and mortar can be approximately divided into two stages stage of primary volatile combustion, and stage of secondary volatile release combined with fixed carbon combustion in isothermal condition with high heating rate. The major gaseous products are CO2, CO, NO, NO2 and SO2. the volatile content is one of the key factors affecting the release rules of gaseous combustion products in asphalt, and reducing the volatile content in asphalt materials can effectively reduce the generation of gaseous combustion products, especially CO.

Study on the composition of the volatile fraction of Hamamelis virginiana.

PubMed

Engel, R; Gutmann, M; Hartisch, C; Kolodziej, H; Nahrstedt, A

1998-04-01

The volatile fractions, obtained by water distillation from the leaves and bark of Hamamelis virginiana L. were analysed in detail by GC-MS. About 175 (leaves) and 168 (bark) compounds have been identified or at least partly characterized on the basis of a computerized database (SeKoMS). The dominating substances were represented by a homologous series of alkanes, alkenes, aliphatic alcohols, related aldehydes, ketones, and fatty acid esters. Importantly, significant differences in the terpenoid and phenylpropanoid patterns of the products obtained from the bark and leaves are apparent: whereas the product of bark distillation was found to typically contain phenylpropanoids and mainly sesquiterpenoids, that obtained from the leaves included some distinct monoterpenoids detected in comparably higher amounts. The chemical composition of the volatiles, when taken together with the absence of specific accumulation sites of lipophilics, emphasizes the definition "volatile fraction" rather than "essential oil".

Constraints on the Chemistry and Abundance of Hydrous Phases in Sub Continental Lithospheric Mantle: Implications for Mid-Lithospheric Discontinuities

NASA Astrophysics Data System (ADS)

Saha, S.; Dasgupta, R.; Fischer, K. M.; Mookherjee, M.

2017-12-01

The origins of a 2-10% reduction in seismic shear wave velocity (Vs) at depths of 60-160 km in sub continental lithospheric mantle (SCLM) regions, identified as the Mid Lithospheric Discontinuity (MLD) [e.g., 1] are highly debated [e.g., 2, 3]. One of the proposed explanations for MLDs is the presence of hydrous minerals such as amphibole and phlogopite at these depths [e.g., 2, 4, 5]. Although the stability and compositions of these phases in peridotite + H2O ± CO2 have been widely explored [e.g., 6], their composition and abundance as a function of permissible SCLM chemistry remain poorly understood. We have compiled phase equilibria experiments conducted over a range of pressure (0.5-8 GPa), temperature (680-1300 °C), major element peridotite compositions, and volatiles (H2O: 0.05-13.79 wt.% and CO2: 0.25-5.3 wt.%). The goal was to constrain how compositional parameters such as CaO and alkali/H2O affect the chemistry and abundance of amphibole and phlogopite. We observe that the abundance of amphibole increases with CaO content and decreasing alkali/H2O. The abundance of phlogopite varies directly with K2O content. Unlike phlogopite compositions that remain consistent, amphibole compositions show variability (pargastitic to K-richterite) depending on bulk CaO and Na2O. Mineral modes, obtained by mass balance on a melt/fluid free basis, were used to calculate aggregate shear wave velocity, Vs for the respective assemblages [e.g., 7] and compared with absolute values observed at MLD depths [e.g., 8]. Vs shows a strong inverse correlation with phlogopite and amphibole modes (particularly where phlogopite is absent). For the Mg# range of cratonic xenoliths, 5-10% phlogopite at MLD depths can match the observed Vs values, while CaO contents in cratonic xenoliths limit the amphibole abundance to 10%, which is lower than previous estimates based on heat flow calculations [e.g., 4]. The modes of hydrous and other phases and corresponding Vs values could be used to identify the process of volatile introduction such that the origin of MLDs could be linked to models of craton formation. [1] Abt et al., 2010, JGR; [2] Rader et al., 2015, G3; [3] Karato et al., 2015, NatGeo; [4] Selway et al., 2015, EPSL; [5] Saha et al., submitted, G3; [6] Mandler and Grove, 2016, CMP; [7] Abers & Hacker, 2016, G3 [8] Hirsch et al., 2015, G3.

Tracing the ingredients for a habitable earth from interstellar space through planet formation

PubMed Central

Bergin, Edwin A.; Blake, Geoffrey A.; Ciesla, Fred; Hirschmann, Marc M.; Li, Jie

2015-01-01

We use the C/N ratio as a monitor of the delivery of key ingredients of life to nascent terrestrial worlds. Total elemental C and N contents, and their ratio, are examined for the interstellar medium, comets, chondritic meteorites, and terrestrial planets; we include an updated estimate for the bulk silicate Earth (C/N = 49.0 ± 9.3). Using a kinetic model of disk chemistry, and the sublimation/condensation temperatures of primitive molecules, we suggest that organic ices and macromolecular (refractory or carbonaceous dust) organic material are the likely initial C and N carriers. Chemical reactions in the disk can produce nebular C/N ratios of ∼1–12, comparable to those of comets and the low end estimated for planetesimals. An increase of the C/N ratio is traced between volatile-rich pristine bodies and larger volatile-depleted objects subjected to thermal/accretional metamorphism. The C/N ratios of the dominant materials accreted to terrestrial planets should therefore be higher than those seen in carbonaceous chondrites or comets. During planetary formation, we explore scenarios leading to further volatile loss and associated C/N variations owing to core formation and atmospheric escape. Key processes include relative enrichment of nitrogen in the atmosphere and preferential sequestration of carbon by the core. The high C/N bulk silicate Earth ratio therefore is best satisfied by accretion of thermally processed objects followed by large-scale atmospheric loss. These two effects must be more profound if volatile sequestration in the core is effective. The stochastic nature of these processes hints that the surface/atmospheric abundances of biosphere-essential materials will likely be variable. PMID:26150527

Tracing the ingredients for a habitable earth from interstellar space through planet formation.

PubMed

Bergin, Edwin A; Blake, Geoffrey A; Ciesla, Fred; Hirschmann, Marc M; Li, Jie

2015-07-21

We use the C/N ratio as a monitor of the delivery of key ingredients of life to nascent terrestrial worlds. Total elemental C and N contents, and their ratio, are examined for the interstellar medium, comets, chondritic meteorites, and terrestrial planets; we include an updated estimate for the bulk silicate Earth (C/N = 49.0 ± 9.3). Using a kinetic model of disk chemistry, and the sublimation/condensation temperatures of primitive molecules, we suggest that organic ices and macromolecular (refractory or carbonaceous dust) organic material are the likely initial C and N carriers. Chemical reactions in the disk can produce nebular C/N ratios of ∼1-12, comparable to those of comets and the low end estimated for planetesimals. An increase of the C/N ratio is traced between volatile-rich pristine bodies and larger volatile-depleted objects subjected to thermal/accretional metamorphism. The C/N ratios of the dominant materials accreted to terrestrial planets should therefore be higher than those seen in carbonaceous chondrites or comets. During planetary formation, we explore scenarios leading to further volatile loss and associated C/N variations owing to core formation and atmospheric escape. Key processes include relative enrichment of nitrogen in the atmosphere and preferential sequestration of carbon by the core. The high C/N bulk silicate Earth ratio therefore is best satisfied by accretion of thermally processed objects followed by large-scale atmospheric loss. These two effects must be more profound if volatile sequestration in the core is effective. The stochastic nature of these processes hints that the surface/atmospheric abundances of biosphere-essential materials will likely be variable.

Extraction of the gate capacitance coupling coefficient in floating gate non-volatile memories: Statistical study of the effect of mismatching between floating gate memory and reference transistor in dummy cell extraction methods

NASA Astrophysics Data System (ADS)

Rafhay, Quentin; Beug, M. Florian; Duane, Russell

2007-04-01

This paper presents an experimental comparison of dummy cell extraction methods of the gate capacitance coupling coefficient for floating gate non-volatile memory structures from different geometries and technologies. These results show the significant influence of mismatching floating gate devices and reference transistors on the extraction of the gate capacitance coupling coefficient. In addition, it demonstrates the accuracy of the new bulk bias dummy cell extraction method and the importance of the β function, introduced recently in [Duane R, Beug F, Mathewson A. Novel capacitance coupling coefficient measurement methodology for floating gate non-volatile memory devices. IEEE Electr Dev Lett 2005;26(7):507-9], to determine matching pairs of floating gate memory and reference transistor.

In vitro antimicrobial activity and chemical composition of the essential oil of Foeniculum vulgare Mill.

PubMed

Aprotosoaie, Ana Clara; Hăncianu, Monica; Poiată, Antonia; Tuchiluş, Cristina; Spac, A; Cioană, Oana; Gille, Elvira; Stănescu, Ursula

2008-01-01

In our study, four samples of volatile oil from Foeniculum vulgare, cultivated in different pedoclimatic conditions, were investigated for their antimicrobial activity and chemical composition. Organisms. Staphylococcus aureus ATCC 25923, Bacillus cereus, Pseudomonas aeruginosa, Escherichia coli ATCC 25922, Candida albicans were included in the report. Antimicrobial susceptibility tests. The comparative inhibitory activity of volatile oil samples with other antimicrobial agents was quantitative determined by minimum inhibitory concentration (MIC). Oil samples are the volatile oils extracted by steam distillation, from two ecological vegetative populations of Foeniculum vulgare. Gas chromatography coupled to mass spectrometry (GC-MS) was used to determine the chemical composition of the essential oils. All oil samples have a good activity against E. coli and S. aureus at low concentrations. Against B. cereus and P. aeruginosa these oil samples are less active. The oil samples were generally bactericidal at a concentration up to twofold or fourfold higher than the MIC value. Significantly synergic activity with amoxicillin or tetracycline showed all fennel samples against E. coli, Sarcina lutea and B. subtilis strains. Fennel oil samples have shown high activity against Candida albicans. No significant antimicrobial activity variations were observed for Foeniculum vulgare volatile oil samples obtained after two or three years cultivation period. The most important identified compounds in all samples of fennel volatile oils were trans-anethole, estragole, fenchone, limonene, alpha-pinene and gamma-terpinene.

Composition of the volatile fraction of a sample of Brazilian green propolic and its phytotoxic activity.

PubMed

Fernandes-Silva, Caroline C; Lima, Carolina A; Negri, Giuseppina; Salatino, Maria L F; Salatino, Antonio; Mayworm, Marco A S

2015-12-01

Propolis is a resinous material produced by honeybees, containing mainly beeswax and plant material. Despite the wide spectrum of biological activity of propolis, to our knowledge no studies have been carried out about phytotoxic properties of Brazilian propolis and its constituents. The aims of this study were to analyze the chemical composition and to evaluate the phytotoxic activity of the volatile fraction of a sample of Brazilian green propolis. Main constituents are the phenylpropanoid 3-prenylcinnamic acid allyl ester (26.3%) and the sesquiterpene spathulenol (23.4%). Several other sesquiterpenes and phenylpropanoids, in addition to linalool and α-terpineol (monoterpenes), were also detected. The activity of solutions of the volatile fraction at 1.0, 0.5 and 0.1% was tested on lettuce seeds and seedlings. The solution at 1% inhibited completely the seed germination and solutions at 0.1 and 0.5% reduced the germination rate index. The solution at 0.5% reduced the growth of the hypocotyl-radicle axis and the development of the cotyledon leaf. The chemical composition of the volatile fraction of this Brazilian green propolis is different from those previously described, and these results may contribute to a better understanding about the chemical variations in propolis. The volatile fraction of Brazilian green propolis influences both germination of seed lettuce and the growth of its seedlings, showing an phytotoxic potential. © 2014 Society of Chemical Industry.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mccall, Scott K.; Kuntz, Joshua D.

A method of making a bulk exchange spring magnet by providing a magnetically soft material, providing a hard magnetic material, and producing a composite of said magnetically soft material and said hard magnetic material to make the bulk exchange spring magnet. The step of producing a composite of magnetically soft material and hard magnetic material is accomplished by electrophoretic deposition of the magnetically soft material and the hard magnetic material to make the bulk exchange spring magnet.

Volatility Properties of Internally- and Externally-Mixed Ambient Aerosols at an Anthropogenically-influenced Forest Site in Southeastern USA

NASA Astrophysics Data System (ADS)

Khlystov, A.; Subramanian, R.

2015-12-01

Secondary organic aerosol (SOA) from biogenic sources has a significant contribution to ambient aerosol loadings in Southeastern USA and thus contributes to adverse health effects of air pollution and influences regional and global climate. Volatility properties of biogenic SOA determine its concentration, reactivity, and lifetime, but are still largely unknown. As part of a larger study to assess the effect of biogenic SOA on aerosol optical properties, a set of instruments, including scanning mobility sizers (SMPS), single particle soot photometer (SP2), and a thermodenuder, was deployed during June 2015 at a Duke Forest site near Chapel Hill, NC. The site is characterized by a significant contribution of both biogenic and urban (mostly traffic) sources. Measurements of changes in aerosol volume and optical size upon heating in the thermodenuder at different temperatures are used to derive volatility properties of the ambient aerosol. A limited set of experiments was carried out using the tandem differential mobility analysis (TDMA) approach to investigate whether the ambient aerosol at the Duke Forest site is internally mixed with respect to its volatility properties. In this presentation we will discuss equilibrium and kinetic aspects of aerosol volatility observed during this study and implications of external vs. internal mixing for derivation of bulk volatility properties of ambient aerosol.

The problem of iron partition between Earth and Moon during simultaneous formation as a double planet system

NASA Technical Reports Server (NTRS)

Cassidy, W. A.

1984-01-01

A planetary model is described which requires fractional vapor/liquid condensation, planet accumulation during condensation, a late start for accumulation of the Moon, and volatile accretion to the surfaces of each planet only near the end of the accumulation process. In the model, initial accumulation of small objects is helped if the agglomerating particles are somewhat sticky. Assuming that growth proceeds through this range, agglomeration continues. If the reservoir of vapor is being preferentially depleted in iron by fractional condensation, an iron-rich planetary core forms. As the temperature decreases, condensing material becomes progressively richer in silicates and poorer in iron, forming the silicate-rich mantle of an already differentiated Earth. A second center of agglomeration successfully forms near the growing Earth after most of the iron in the reservoir has been used up. The bulk composition of the Moon then is similar to the outer mantle of the accumulating Earth.

Isotopic signatures and distribution of nitrogen and trapped and radiogenic xenon in the Acapulco and FRO90011 meteorites

NASA Technical Reports Server (NTRS)

Kim, Y.; Marti, K.

1993-01-01

Acapulco metal and silicate show distinct N isotopic signatures. Trapped heavy noble gases are carried by 'magnetic' opx and radiogenic Xe-129 excesses are observed in phosphate and in minor surficial phases on metal grains. N and Xe isotopic signatures in FRO90011 do not agree with those observed in Acapulco. The Acapulco meteorite is unique in having achondritic texture and chondritic composition. Its mineralogical study shows the record of high temperature (1100 C) recrystallization. However, this meteorite shows abundances of volatile elements close to the levels observed in carbonaceous chondrites and concentrations of heavy noble gases comparable to those observed in type 4 ordinary chondrites, not expected for a presumed highly equilibrated object. Nitrogen measurements in bulk Acapulco revealed two different isotopic signatures, in apparent conflict with evidence for a high degree of recrystallization. N and Xe were studied in separated mineral phases to search for the carriers in order to better understand the formation and thermal history of the Acapulco parent body.

Variations in Volatile Oil Yield and Composition of "Xin-yi" (Magnolia biondii Pamp. Flower Buds) at Different Growth Stages.

PubMed

Hu, Mingli; Bai, Mei; Ye, Wei; Wang, Yaling; Wu, Hong

2018-06-01

Dried flower buds of Magnolia biondii Pamp. are the main ingredient in "Xin-yi" in China, and the volatile oils of M. biondii flower buds are the principal medicinal component. Gas chromatographymass spectrometry (GC-MS) and microscopic techniques were employed to detect the volatile yields of M. biondii flowers at various growth stages. The volatile oil yields of M. biondii flowers differed significantly at different growth stages and were closely related to flower dry weight, oil cell density and degree of oil accumulation. In February 2016, flower buds had the highest dry weight, the maximum percentage of oil cells at the oil saturation stage and the highest density of oil cells, which coincided with the highest oil yield. In March 2016, flower buds had a lower dry weight, a higher percentage of oil cells at the oil-degrading stage and the lowest oil cell density, resulting in decreased oil yields. The total amounts of the major medicinal components in the M. biondii flower also showed regular changes at different growth stages. In January and February of 2016, M. biondii flowers had a higher dry weight, volatile oil yield and total content of medicinal ingredients, which was the best time for harvesting high-quality medicinal components. Our study reveals that volatile oil content and chemical composition are closely related to the growth stage of M. biondii flower buds. The results provide a scientific morphology and composition index for evaluating the medicinal value and harvesting of high-quality M. biondii medicinal herbs.

Marginal Gap Formation in Approximal "Bulk Fill" Resin Composite Restorations After Artificial Ageing.

PubMed

Peutzfeldt, A; Mühlebach, S; Lussi, A; Flury, S

The aim of this in vitro study was to investigate the marginal gap formation of a packable "regular" resin composite (Filtek Supreme XTE [3M ESPE]) and two flowable "bulk fill" resin composites (Filtek Bulk Fill [3M ESPE] and SDR [DENTSPLY DeTrey]) along the approximal margins of Class II restorations. In each of 39 extracted human molars (n=13 per resin composite), mesial and distal Class II cavities were prepared, placing the gingival margins below the cemento-enamel junction. The cavities were restored with the adhesive system OptiBond FL (Kerr) and one of the three resin composites. After restoration, each molar was cut in half in the oro-vestibular direction between the two restorations, resulting in two specimens per molar. Polyvinylsiloxane impressions were taken and "baseline" replicas were produced. The specimens were then divided into two groups: At the beginning of each month over the course of six months' tap water storage (37°C), one specimen per molar was subjected to mechanical toothbrushing, whereas the other was subjected to thermocycling. After artificial ageing, "final" replicas were produced. Baseline and final replicas were examined under the scanning electron microscope (SEM), and the SEM micrographs were used to determine the percentage of marginal gap formation in enamel or dentin. Paramarginal gaps were registered. The percentages of marginal gap formation were statistically analyzed with a nonparametric analysis of variance followed by Wilcoxon-Mann-Whitney tests and Wilcoxon signed rank tests, and all p-values were corrected with the Bonferroni-Holm adjustment for multiple testing (significance level: α=0.05). Paramarginal gaps were analyzed descriptively. In enamel, significantly lower marginal gap formation was found for Filtek Supreme XTE compared to Filtek Bulk Fill ( p=0.0052) and SDR ( p=0.0289), with no significant difference between Filtek Bulk Fill and SDR ( p=0.4072). In dentin, significantly lower marginal gap formation was found for SDR compared to Filtek Supreme XTE ( p<0.0001) and Filtek Bulk Fill ( p=0.0015), with no significant difference between Filtek Supreme XTE and Filtek Bulk Fill ( p=0.4919). Marginal gap formation in dentin was significantly lower than in enamel ( p<0.0001). The percentage of restorations with paramarginal gaps varied between 0% and 85%, and for all three resin composites the percentages were markedly higher after artificial ageing. The results from this study suggest that in terms of marginal gap formation in enamel, packable resin composites may be superior to flowable "bulk fill" resin composites, while in dentin some flowable "bulk fill" resin composites may be superior to packable ones.

Maruyamaite, a new K-dominant tourmaline coexisting with diamond -an important accessory mineral in UHP rocks

NASA Astrophysics Data System (ADS)

Stock, M. J.; Humphreys, M.; Smith, V.; Pyle, D. M.; Isaia, R.

2014-12-01

The apatite crystal structure is capable of incorporating H2O, F and Cl, as well as trace CO2 and sulphur. These can be related to parental magma compositions through application of a series of pressure and temperature-dependent exchange reactions (Piccoli and Candela, 1994), permitting apatite crystals to preserve a record of all major volatile species in the melt. Furthermore, due to the general incompatibility of P in other rock-forming minerals, apatite is ubiquitous in igneous systems and often begins crystallising early, such that apatite inclusions within phenocrysts record melt volatile contents throughout magmatic differentiation. In this work, we compare the compositions of apatite inclusions and microphenocrysts with pyroxene-hosted melt inclusions from the Astroni 1 eruption of Campi Flegrei, Italy. These data are coupled with magmatic differentiation models (Gualda et al., 2012), experimental volatile solubility data (Webster et al., 2014) and thermodynamic models of apatite compositional variations (Piccoli and Candela, 1994) to determine a time-series of magmatic volatile evolution in the build-up to eruption. We find that apatite halogen/OH ratios decreased through magmatic differentiation, while melt inclusion F and Cl concentrations increased. Melt inclusion H2O contents are constant at ~2.5 wt%. These data are best explained by volatile-undersaturated differentiation over most of the crystallisation history of the Astroni 1 melt, with melt inclusion H2O contents reset during ascent, due to rapid H diffusion through the phenocryst hosts (Woods et al., 2000). Given the rapid diffusivity of volatiles in apatite (Brenan, 1993), preservation of undersaturated compositions in microphenocrysts suggests that saturation was only achieved a few days to months before eruption and that it may have been the transition into a volatile-saturated state that ultimately triggered eruption. Piccoli and Candela, 1994. Am. J. of Sc., 294, 92-135. Gualda et al., 2012. J. Pet., 53, 875-890. Webster et al., 2014. J. Pet., 55, 2217-2248. Woods et al., 2000. Am. Min., 85, 480-487. Brenan, 1993. Chem. Geol., 110, 195-210.

The influences of ambient particle composition and size on particle infiltration in Los Angeles, CA, residences.

PubMed

Sarnat, Stefanie Ebelt; Coull, Brent A; Ruiz, Pablo A; Koutrakis, Petros; Suh, Helen H

2006-02-01

Particle infiltration is a key determinant of the indoor concentrations of ambient particles. Few studies have examined the influence of particle composition on infiltration, particularly in areas with high concentrations of volatile particles, such as ammonium nitrate (NH4NO3). A comprehensive indoor monitoring study was conducted in 17 Los Angeles-area homes. As part of this study, indoor/outdoor concentration ratios during overnight (nonindoor source) periods were used to estimate the fraction of ambient particles remaining airborne indoors, or the particle infiltration factor (FINF), for fine particles (PM2.5), its nonvolatile (i.e., black carbon [BC]) and volatile (i.e., nitrate [NO3-]) components, and particle sizes ranging between 0.02 and 10 microm. FINF was highest for BC (median = 0.84) and lowest for NO3- (median = 0.18). The low FINF for NO3- was likely because of volatilization of NO3- particles once indoors, in addition to depositional losses upon building entry. The FINF for PM2.5 (median = 0.48) fell between those for BC and NO3-, reflecting the contributions of both particle components to PM25. FINF varied with particle size, air-exchange rate, and outdoor NO3- concentrations. The FINF for particles between 0.7 and 2 microm in size was considerably lower during periods of high as compared with low outdoor NO3- concentrations, suggesting that outdoor NO3- particles were of this size. This study demonstrates that infiltration of PM2.5 varies by particle component and is lowest for volatile species, such as NH4NO3. Our results suggest that volatile particle components may influence the ability for outdoor PM concentrations to represent indoor and, thus, personal exposures to particles of ambient origin, because volatilization of these particles causes the composition of PM2.5 to differ indoors and outdoors. Consequently, particle composition likely influences observed epidemiologic relationships based on outdoor PM concentrations, especially in areas with high concentrations of NH4NO3 and other volatile particles.

Volatility of organic aerosol and its components in the megacity of Paris

NASA Astrophysics Data System (ADS)

Paciga, Andrea; Karnezi, Eleni; Kostenidou, Evangelia; Hildebrandt, Lea; Psichoudaki, Magda; Engelhart, Gabriella J.; Lee, Byong-Hyoek; Crippa, Monica; Prévôt, André S. H.; Baltensperger, Urs; Pandis, Spyros N.

2016-02-01

Using a mass transfer model and the volatility basis set, we estimate the volatility distribution for the organic aerosol (OA) components during summer and winter in Paris, France as part of the collaborative project MEGAPOLI. The concentrations of the OA components as a function of temperature were measured combining data from a thermodenuder and an aerosol mass spectrometer (AMS) with Positive Matrix Factorization (PMF) analysis. The hydrocarbon-like organic aerosol (HOA) had similar volatility distributions for the summer and winter campaigns with half of the material in the saturation concentration bin of 10 µg m-3 and another 35-40 % consisting of low and extremely low volatility organic compounds (LVOCs with effective saturation concentrations C* of 10-3-0.1 µg m-3 and ELVOCs C* less or equal than 10-4 µg m-3, respectively). The winter cooking OA (COA) was more than an order of magnitude less volatile than the summer COA. The low-volatility oxygenated OA (LV-OOA) factor detected in the summer had the lowest volatility of all the derived factors and consisted almost exclusively of ELVOCs. The volatility for the semi-volatile oxygenated OA (SV-OOA) was significantly higher than that of the LV-OOA, containing both semi-volatile organic components (SVOCs with C* in the 1-100 µg m-3 range) and LVOCs. The oxygenated OA (OOA) factor in winter consisted of SVOCs (45 %), LVOCs (25 %) and ELVOCs (30 %). The volatility of marine OA (MOA) was higher than that of the other factors containing around 60 % SVOCs. The biomass burning OA (BBOA) factor contained components with a wide range of volatilities with significant contributions from both SVOCs (50 %) and LVOCs (30 %). Finally, combining the bulk average O : C ratios and volatility distributions of the various factors, our results are placed into the two-dimensional volatility basis set (2D-VBS) framework. The OA factors cover a broad spectrum of volatilities with no direct link between the average volatility and average O : C of the OA components.

Melt inclusion evidence for a volatile-enriched (H2O, Cl, B) component in parental magmas of Gorgona Island komatiites

NASA Astrophysics Data System (ADS)

Kamenetsky, V.; Sobolev, A.; McDonough, W.

2003-04-01

Late Cretaceous komatiites of Gorgona Island are unambiguous samples of ultra-mafic melts related to a hot and possibly 'wet' mantle plume. Despite significant efforts in studying komatiites, their volatile abundances remain largely unknown because of significant alteration of rocks and lack of fresh glasses. This work presents major, trace and volatile element data for 22 partially homogenised (at 1275oC and 1 bar pressure) melt inclusions in olivine (Fo 90.5-91.5) from a Gorgona Isl. komatiite (# Gor 94-3). Major element compositions (except FeO which is notably lower by up to 5 wt% as a result of post-entrapment re-equilibration) and most lithophile trace elements of melt inclusions are indistinguishable from the whole rock komatiites. With the exception of three inclusions that have low Na, H2O, Cl, F and S (likely compromised and degassed during heating) most compositions are characterised by relatively constant and high volatile abundances (H2O 0.4-0.8 wt%, Cl 0.02-0.03 wt%, B 0.8-1.4 ppm). These are interpreted as representative of original volatiles in parental melts because they correspond to the internal volatile pressure in the closed inclusions significantly exceeding 1 bar pressure of heating experiment. Although H2O is strongly enriched (PM-normalised H2O/Ce 10-17) its concentrations correlate well with many elements (e.g. Yb, Er, Y, Ti, Sr, Be). Other positive anomalies on the overall depleted (La/Sm 0.26-0.33) PM normalized compositional spectra of melt inclusions are shown by B (B/K 2.4-5.4) and Cl (Cl/K 11-16). Compositions of melt inclusions, when corrected for Fe loss and recalculated in equilibrium with host olivine, have high MgO (15.4-16.4 wt%; Mg# of 74) and substantial H2O (0.4-0.6 wt%) contents. This together with the data on other 'enriched' elements argues for the presence of previously unknown volatile-enriched component in the parental melts of Gorgona Isl. komatiites. We discuss contamination of magmas by altered oceanic crust in the plumbing system, the involvement of volatile-rich subduction related component(s) in the mantle source, and the geochemical control from residual garnet during the generation of komatiite primary melts.

Constraining the volatile fraction of planets from transit observations

NASA Astrophysics Data System (ADS)

Alibert, Y.

2016-06-01

Context. The determination of the abundance of volatiles in extrasolar planets is very important as it can provide constraints on transport in protoplanetary disks and on the formation location of planets. However, constraining the internal structure of low-mass planets from transit measurements is known to be a degenerate problem. Aims: Using planetary structure and evolution models, we show how observations of transiting planets can be used to constrain their internal composition, in particular the amount of volatiles in the planetary interior, and consequently the amount of gas (defined in this paper to be only H and He) that the planet harbors. We first explore planets that are located close enough to their star to have lost their gas envelope. We then concentrate on planets at larger distances and show that the observation of transiting planets at different evolutionary ages can provide statistical information on their internal composition, in particular on their volatile fraction. Methods: We computed the evolution of low-mass planets (super-Earths to Neptune-like) for different fractions of volatiles and gas. We used a four-layer model (core, silicate mantle, icy mantle, and gas envelope) and computed the internal structure of planets for different luminosities. With this internal structure model, we computed the internal and gravitational energy of planets, which was then used to derive the time evolution of the planet. Since the total energy of a planet depends on its heat capacity and density distribution and therefore on its composition, planets with different ice fractions have different evolution tracks. Results: We show for low-mass gas-poor planets that are located close to their central star that assuming evaporation has efficiently removed the entire gas envelope, it is possible to constrain the volatile fraction of close-in transiting planets. We illustrate this method on the example of 55 Cnc e and show that under the assumption of the absence of gas, the measured mass and radius imply at least 20% of volatiles in the interior. For planets at larger distances, we show that the observation of transiting planets at different evolutionary ages can be used to set statistical constraints on the volatile content of planets. Conclusions: These results can be used in the context of future missions like PLATO to better understand the internal composition of planets, and based on this, their formation process and potential habitability.

ZnO nanorod array polydimethylsiloxane composite solid phase micro-extraction fiber coating: fabrication and extraction capability.

PubMed

Wang, Dan; Wang, Qingtang; Zhang, Zhuomin; Chen, Guonan

2012-01-21

ZnO nanorod array coating is a novel kind of solid-phase microextraction (SPME) fiber coating which shows good extraction capability due to the nanostructure. To prepare the composite coating is a good way to improve the extraction capability. In this paper, the ZnO nanorod array polydimethylsiloxane (PDMS) composite SPME fiber coating has been prepared and its extraction capability for volatile organic compounds (VOCs) has been studied by headspace sampling the typical volatile mixed standard solution of benzene, toluene, ethylbenzene and xylene (BTEX). Improved detection limit and good linear ranges have been achieved for this composite SPME fiber coating. Also, it is found that the composite SPME fiber coating shows good extraction selectivity to the VOCs with alkane radicals.

Dynamic analysis of bulk-fill composites: Effect of food-simulating liquids.

PubMed

Eweis, Ahmed Hesham; Yap, Adrian U-Jin; Yahya, Noor Azlin

2017-10-01

This study investigated the effect of food simulating liquids on visco-elastic properties of bulk-fill restoratives using dynamic mechanical analysis. One conventional composite (Filtek Z350 [FZ]), two bulk-fill composites (Filtek Bulk-fill [FB] and Tetric N Ceram [TN]) and a bulk-fill giomer (Beautifil-Bulk Restorative [BB]) were evaluated. Specimens (12 × 2 × 2mm) were fabricated using customized stainless steel molds. The specimens were light-cured, removed from their molds, finished, measured and randomly divided into six groups. The groups (n = 10) were conditioned in the following mediums for 7 days at 37°C: air (control), artificial saliva (SAGF), distilled water, 0.02N citric acid, heptane, 50% ethanol-water solution. Specimens were assessed using dynamic mechanical testing in flexural three-point bending mode and their respective mediums at 37°C and a frequency range of 0.1-10Hz. The distance between the supports were fixed at 10mm and an axial load of 5N was employed. Data for elastic modulus, viscous modulus and loss tangent were subjected to ANOVA/Tukey's tests at significance level p < 0.05. Significant differences in visco-elastic properties were observed between materials and mediums. Apart from bulk-fill giomer, elastic modulus was the highest after conditioning in heptane. No apparent trends were noted for viscous modulus. Generally, loss tangent was the highest after conditioning in ethanol. The effect of food-simulating liquids on the visco-elastic properties of bulk-fill composites was material and medium dependent. Copyright © 2017 Elsevier Ltd. All rights reserved.

Core-Mantle Partitioning of Volatile Siderophile Elements and the Origin of Volatile Elements in the Earth

NASA Technical Reports Server (NTRS)

Nickodem, K.; Righter, K.; Danielson, L.; Pando, K.; Lee, C.

2012-01-01

There are currently several hypotheses on the origin of volatile siderophile elements in the Earth. One hypothesis is that they were added during Earth s accretion and core formation and mobilized into the metallic core [1], others claim multiple stage origin [2], while some hypothesize that volatiles were added after the core already formed [3]. Several volatile siderophile elements are depleted in Earth s mantle relative to the chondrites, something which continues to puzzle many scientists. This depletion is likely due to a combination of volatility and core formation. The Earth s core is composed of Fe and some lighter constituents, although the abundances of these lighter elements are unknown [4]. Si is one of these potential light elements [5] although few studies have analyzed the effect of Si on metal-silicate partitioning, in particular the volatile elements. As, In, Ge, and Sb are trace volatile siderophile elements which are depleted in the mantle but have yet to be extensively studied. The metal-silicate partition coefficients of these elements will be measured to determine the effect of Si. Partition coefficients depend on temperature, pressure, oxygen fugacity, and metal and silicate composition and can constrain the concentrations of volatile, siderophile elements found in the mantle. Reported here are the results from 13 experiments examining the partitioning of As, In, Ge, and Sb between metallic and silicate liquid. These experiments will examine the effect of temperature, and metal-composition (i.e., Si content) on these elements in or-der to gain a greater understanding of the core-mantle separation which occurred during the Earth s early stages. The data can then be applied to the origin of volatile elements in the Earth.

Apatite-Melt Partitioning of Volatiles in Basaltic Systems: Implications for Determining Volatile Abundances in Planetary Bodies from Apatite

NASA Technical Reports Server (NTRS)

McCubbin, F. M.

2017-01-01

Apatite [Ca5(PO4)3(F,Cl,OH)] is present in a wide range of planetary materials, and due to the presence of volatiles within its crystal structure (X-site), many recent studies have attempted to use apatite to constrain the volatile contents of planetary magmas and mantle sources [i.e., 1]. Experimental studies have investigated the apatite-melt partitioning behavior of F, Cl, and OH in basaltic systems [e.g., 2- 3], reporting that apatite-melt partitioning of volatiles is best described as exchange equilibria similar to Fe-Mg partitioning between olivine and silicate melt. However, exchange coefficients may vary as a function of temperature, pressure, melt composition, and/or oxygen fugacity. Furthermore, exchange coefficients may vary in portions of apatite compositional space where F, Cl, and OH do not mix ideally in apatite [3]. In these regions of ternary space, we anticipate that crystal chemistry could influence partitioning behavior. Consequently, we conducted experiments to investigate the effect of apatite crystal chemistry on apatite-melt partitioning of F, Cl, and OH.

GC-MS Profiling of Volatile Components in Different Fermentation Products of Cordyceps Sinensis Mycelia.

PubMed

Zhang, Hongyang; Li, Yahui; Mi, Jianing; Zhang, Min; Wang, Yuerong; Jiang, Zhihong; Hu, Ping

2017-10-24

The fermentation products of Cordyceps sinensis ( C. sinensis ) mycelia are sustainable substitutes for natural C. sinensis . However, the volatile compositions of the commercial products are still unclear. In this paper, we have developed a simultaneous distillation-extraction (SDE) and gas chromatography-mass spectrometry (GC-MS) method for the profiling of volatile components in five fermentation products. A total of 64, 39, 56, 52, and 44 components were identified in the essential oils of Jinshuibao capsule (JSBC), Bailing capsule (BLC), Zhiling capsule (ZLC), Ningxinbao capsule (NXBC), and Xinganbao capsule (XGBC), respectively. 5,6-Dihydro-6-pentyl-2H-pyran-2-one (massoia lactone) was first discovered as the dominant component in JSBC volatiles. Fatty acids including palmitic acid (C16:0) and linoleic acid (C18:2) were also found to be major volatile compositions of the fermentation products. The multivariate partial least squares-discriminant analysis (PLS-DA) showed a clear discrimination among the different commercial products as well as the counterfeits. This study may provide further chemical evidences for the quality evaluation of the fermentation products of C. sinensis mycelia.

Effects of NOx on the volatility of secondary organic aerosol from isoprene photooxidation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, Lu; Kollman, Matthew S.; Song, Chen

2014-01-28

The effects of NOx on the volatility of the secondary organic aerosol (SOA) formed from isoprene photooxidation are investigated in environmental chamber experiments. Two types of experiments are performed. In HO2-dominant experiments, organic peroxy radicals (RO2) primarily react with HO2. In mixed experiments, RO2 reacts through multiple pathways. The volatility and oxidation state of isoprene SOA is sensitive to and displays a non-linear dependence on NOx levels. When initial NO/isoprene ratio is approximately 3 (ppbv:ppbv), SOA are shown to be most oxidized and least volatile, associated with the highest SOA yield. A High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) is appliedmore » to characterize the key chemical properties of aerosols. While the composition of SOA in mixed experiments does not change substantially over time, SOA become less volatile and more oxidized as oxidation progresses in HO2-dominant experiments. Analysis of the SOA composition suggests that the further reactions of organic peroxides and alcohols may produce carboxylic acids, which might play a strong role in SOA aging.« less

Characterization of Chemical Composition of Pericarpium Citri Reticulatae Volatile Oil by Comprehensive Two-Dimensional Gas Chromatography with High-Resolution Time-of-Flight Mass Spectrometry.

PubMed

Qin, Kunming; Zheng, Lijuan; Cai, Hao; Cao, Gang; Lou, Yajing; Lu, Tulin; Shu, Yachun; Zhou, Wei; Cai, Baochang

2013-01-01

Pericarpium Citri Reticulatae (Chenpi in Chinese) has been widely used as an herbal medicine in Korea, China, and Japan. Chenpi extracts are used to treat indigestion and inflammatory syndromes of the respiratory tract such as bronchitis and asthma. This thesis will analyze chemical compositions of Chenpi volatile oil, which was performed by comprehensive two-dimensional gas chromatography with high-resolution time-of-flight mass spectrometry (GC × GC-HR-TOFMS). One hundred and sixty-seven components were tentatively identified, and terpene compounds are the main components of Chenpi volatile oil, a significant larger number than in previous studies. The majority of the eluted compounds, which were identified, were well separated as a result of high-resolution capability of the GC × GC method, which significantly reduces, the coelution. β -Elemene is tentatively qualified by means of GC × GC in tandem with high-resolution TOFMS detection, which plays an important role in enhancing the effects of many anticancer drugs and in reducing the side effects of chemotherapy. This study suggests that GC × GC-HR-TOFMS is suitable for routine characterization of chemical composition of volatile oil in herbal medicines.

Thermo-Chemical Conversion of Microwave Activated Biomass Mixtures

NASA Astrophysics Data System (ADS)

Barmina, I.; Kolmickovs, A.; Valdmanis, R.; Vostrikovs, S.; Zake, M.

2018-05-01

Thermo-chemical conversion of microwave activated wheat straw mixtures with wood or peat pellets is studied experimentally with the aim to provide more effective application of wheat straw for heat energy production. Microwave pre-processing of straw pellets is used to provide a partial decomposition of the main constituents of straw and to activate the thermo-chemical conversion of wheat straw mixtures with wood or peat pellets. The experimental study includes complex measurements of the elemental composition of biomass pellets (wheat straw, wood, peat), DTG analysis of their thermal degradation, FTIR analysis of the composition of combustible volatiles entering the combustor, the flame temperature, the heat output of the device and composition of the products by comparing these characteristics for mixtures with unprocessed and mw pre-treated straw pellets. The results of experimental study confirm that mw pre-processing of straw activates the thermal decomposition of mixtures providing enhanced formation of combustible volatiles. This leads to improvement of the combustion conditions in the flame reaction zone, completing thus the combustion of volatiles, increasing the flame temperature, the heat output from the device, the produced heat energy per mass of burned mixture and decreasing at the same time the mass fraction of unburned volatiles in the products.

Chemical characterization of oak heartwood from Spanish forests of Quercus pyrenaica (Wild.). Ellagitannins, low molecular weight phenolic, and volatile compounds.

PubMed

Fernandez de Simón, Brígida; Sanz, Miriam; Cadahía, Estrella; Poveda, Pilar; Broto, Miguel

2006-10-18

The need for new sources of quality wood supply for cooperage has led to looking into the possibility of utilizing Quercus pyrenaica Wild. oak, a species native to the Iberian peninsula, as an alternative to other European (Quercus robur and Qurecus petraea) and American (Quercus alba) oaks. The low molecular weight phenolic composition, ellagitannins, and volatile compounds (including a wide range of compound families such as volatile phenols, furanic compounds, lactones, phenyl ketones, other lignin-derived compounds, and volatile compounds related to off-flavors) of green heartwood from Spanish forest regions were studied by HPLC and GC, in order to know its enological characteristics. The chemical composition of Q. pyrenaica is similar to that of other species commonly used in cooperage to make barrels, showing only quantitative differences that were more significant with respect to American than to French species. The four provenance regions studied showed similar chemical composition, with high variability among individuals, often higher than the variability among regions of provenance, but in line with that described in other European and American oak woods. Therefore, this species must be considered to be suitable for aging wine.

Composition of sulla (Hedysarum coronarium L.) honey solvent extractives determined by GC/MS: norisoprenoids and other volatile organic compounds.

PubMed

Jerković, Igor; Tuberoso, Carlo I G; Tuberso, Carlo I G; Gugić, Mirko; Bubalo, Dragan

2010-09-09

Samples of unifloral sulla (Hedysarum coronarum L.) honey from Sardinia (Italy) were analysed. To investigate the chemical composition of the honey volatiles two solvent systems were used for ultrasonic solvent extraction (USE): 1) a 1:2 (v/v) pentane and diethyl ether mixture and 2) dichloromethane. All the extracts were analysed by GC and GC/MS. These procedures have permitted the identification of 56 compounds that include norisoprenoids, benzene derivatives, aliphatic compounds and Maillard reaction products. Norisoprenoids were the major compounds in both extracts, dominated by vomifoliol (5.3-11.2%; 9.6-14.0%) followed by minor percentages of other norisoprenoids such as α-isophorone, 4-ketoisophorone, 3-oxo-α-ionol or 3-oxo-α-ionone. Other abundant single compounds in the extracts were 3-hydroxy-4-phenylbutan-2-one (0.8-5.4%; 0.6-5.7%) and methyl syringate (3.0-5.7%; 2.2-4.1%). The composition of the volatiles and semi-volatiles in the obtained extracts suggests that sulla honey is quite distinctive relative to the other honeys that have been chemically studied by GC/MS, but no specific markers of the honey botanical origin were found.

Polymerization stress evolution of a bulk-fill flowable composite under different compliances.

PubMed

Guo, Yongwen; Landis, Forrest A; Wang, Zhengzhi; Bai, Ding; Jiang, Li; Chiang, Martin Y M

2016-04-01

To use a compliance-variable instrument to simultaneously measure and compare the polymerization stress (PS) evolution, degree of conversion (DC), and exotherm of a bulk-fill flowable composite to a packable composite. A bulk-fill flowable composite (Filtek Bulk-fill, FBF) and a conventional packable composite (Filtek Z250, Z250) purchased from 3M ESPE were investigated. The composites were studied using a cantilever-beam based instrument equipped with an in situ near infrared (NIR) spectrometer and a microprobe thermocouple. The measurements were carried out under various instrumental compliances (ranging from 0.3327μm/N to 12.3215μm/N) that are comparable to the compliances of clinically prepared tooth cavities. Correlations between the PS and temperature change as well as the DC were interpreted. The maximum PS of both composites at 10min after irradiation decreased with the increase in the compliance of the cantilever beam. The FBF composite generated a lower final stress than the Z250 sample under instrumental compliances less than ca. 4μm/N; however, both materials generated statistically similar PS values at higher compliances. The reaction exotherm and the DC of both materials were found to be independent of compliance. The DC of the FBF sample was slightly higher than that of the packable Z250 composite while the peak exotherm of FBF was almost double that of the Z250 composite. For FBF, a characteristic drop in the PS was observed during the early stage of polymerization for all compliances studied which was not observed in the Z250 sample. This drop was shown to relate to the greater exotherm of the less-filled FBF sample relative to the Z250 composite. While the composites with lower filler content (low viscosity) are generally considered to have lower PS than the conventional packable composites, a bulk-fill flowable composite was shown to produce lower PS under a lower compliance of constraint as would be experienced if the composite was used as the base material in clinical procedures. Published by Elsevier Ltd.

Chemical Controls of Ozone Dry Deposition to the Sea Surface Microlayer

NASA Astrophysics Data System (ADS)

Carpenter, L.; Chance, R.; Tinel, L.; Saint, A.; Sherwen, T.; Loades, D.; Evans, M. J.; Boxhall, P.; Hamilton, J.; Stolle, C.; Wurl, O.; Ribas-Ribas, M.; Pereira, R.

2017-12-01

Oceanic dry deposition of atmospheric ozone (O3) is both the largest and most uncertain O3 depositional sink, and is widely acknowledged to be controlled largely by chemical reactions in the sea surface microlayer (SML) involving iodide (I-) and dissolved organic material (DOM). These reactions not only determine how quickly O3 can be removed from the atmosphere, but also result in emissions of trace gases including volatile organic compounds and may constitute a source of secondary organic aerosols to the marine atmosphere. Iodide concentrations at the sea surface vary by approximately an order of magnitude spatially, leading to more than fivefold variation in ozone deposition velocities (and volatile iodine fluxes). Sea-surface temperature is a reasonable predictor of [I-], however two recent parameterisations for surface I- differ by a factor of two at low latitudes. The nature and reactivity of marine DOM to O3 is almost completely unknown, although studies have suggested approximately equivalent chemical control of I- and DOM on ozone deposition. Here we present substantial new measurements of oceanic I- in both bulk seawater and the overlying SML, and show improved estimates of the global sea surface iodide distribution. We also present analyses of water-soluble DOM isolated from the SML and bulk seawater, and corresponding laboratory studies of ozone uptake to bulk and SML seawater, with the aim of characterizing the reactivity of O3 towards marine DOM.

Thermo-optical properties of residential coals and combustion aerosols

NASA Astrophysics Data System (ADS)

Pintér, Máté; Ajtai, Tibor; Kiss-Albert, Gergely; Kiss, Diána; Utry, Noémi; Janovszky, Patrik; Palásti, Dávid; Smausz, Tomi; Kohut, Attila; Hopp, Béla; Galbács, Gábor; Kukovecz, Ákos; Kónya, Zoltán; Szabó, Gábor; Bozóki, Zoltán

2018-04-01

In this study, we present the inherent optical properties of carbonaceous aerosols generated from various coals (hard through bituminous to lignite) and their correlation with the thermochemical and energetic properties of the bulk coal samples. The nanoablation method provided a unique opportunity for the comprehensive investigation of the generated particles under well controlled laboratory circumstances. First, the wavelength dependent radiative features (optical absorption and scattering) and the size distribution (SD) of the generated particulate matter were measured in-situ in aerosol phase using in-house developed and customised state-of-the-art instrumentation. We also investigated the morphology and microstructure of the generated particles using Transmission Electron Microscopy (TEM) and Electron Diffraction (ED). The absorption spectra of the measured samples (quantified by Absorption Angström Exponent (AAE)) were observed to be distinctive. The correlation between the thermochemical features of bulk coal samples (fixed carbon (FC) to volatile matter (VM) ratio and calorific value (CV)) and the AAE of aerosol assembly were found to be (r2 = 0.97 and r2 = 0.97) respectively. Lignite was off the fitted curves in both cases most probably due to its high optically inactive volatile material content. Although more samples are necessary to be investigated to draw statistically relevant conclusion, the revealed correlation between CV and Single Scattering Albedo (SSA) implies that climatic impact of coal combusted aerosol could depend on the thermal and energetic properties of the bulk material.

Are Makemake and Eris Sputnik Planets?

NASA Astrophysics Data System (ADS)

Grundy, William M.; Umurhan, Orkan M.

2017-10-01

Makemake and Eris have high albedos (Sicardy et al. 2011; Ortiz et al. 2012) and show strong spectral absorption by CH4 ice (Licandro et al. 2006; Brown et al. 2007; Dumas et al. 2007). Energetic space radiation breaks C-H bonds in CH4 producing fragments that recombine into dark, red macromolecular materials (tholins, e.g., Johnson et al. 1987; Thompson et al. 1987; Strazzulla et al. 1991). This fact, coupled with Pluto's strong CH4 ice absorption bands and high albedo led Stern (1988) to pose the question "why is Pluto bright?". New Horizons has confirmed that Pluto refreshes its surface via seasonal volatile transport (e.g., Stern et al. 2015). However, one part of Pluto refreshes itself in a different way, too. This is the informally named Sputnik Planitia, a vast plain of volatile ice partly filling a probable impact basin. The ice is thick enough to act as a barrier to internal radiogenic heat flow, which drives convective overturning on 105 to 106 year timescales (e.g., McKinnon et al. 2016; Trowbridge et al 2016). Vigorous convection in Sputnik mixes radiolytic products from the surface down into the bulk of the ice, diluting it, and thus maintaining the high albedo of the surface.We propose that the surfaces of Eris and Makemake are similarly refreshed by convection in deep volatile ice deposits, perhaps covering the majority of their surfaces, unlike Pluto's Sputnik, which only covers a small fraction. The local fluxes of energetic radiation dictate production rates for tholin. Assuming steady-state production over the age of the solar system and mixing into the volatile ice, the colors and albedos of the bodies can be used to estimate the thickness of the volatile ice into which the tholin has been diluted through convective mixing. Likewise, for plausible radiogenic internal heat production, lower limits can be set on the thickness of the ice, to support convective mixing. We don't know the rheological properties of mixed N2+CH4 ice, let alone what happens when plausible additional contaminants, such as CO, Ar, C2H2, C2H4, C2H6, etc. are added, but bounding cases for N2-dominated and CH4-dominated ice compositions can be calculated.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Min Ho; Rhyee, Jong-Soo, E-mail: jsrhyee@khu.ac.kr

We investigated the thermoelectric properties of PbTe/Ag{sub 2}Te bulk composites, synthesized by hand milling, mixing, and hot press sintering. From x-ray diffraction and energy dispersive x-ray spectroscopy measurements, we observed Ag{sub 2}Te phase separation in the PbTe matrix without Ag atom diffusion. In comparison with previously reported pseudo-binary (PbTe){sub 1−x}(Ag{sub 2}Te){sub x} composites, synthesized by high temperature phase separation, the PbTe/Ag{sub 2}Te bulk composites fabricated with a low temperature phase mixing process give rise to p-type conduction of carriers with significantly decreased electrical conductivity. This indicates that Ag atom diffusion in the PbTe matrix changes the sign of the Seebeckmore » coefficient to n-type and also increases the carrier concentration. Effective p-type doping with low temperature phase separation by mixing and hot press sintering can enhance the thermoelectric performance of PbTe/Ag{sub 2}Te bulk composites, which can be used as a p-type counterpart of n-type (PbTe){sub 1−x}(Ag{sub 2}Te){sub x} bulk composites.« less

Processing and Properties of a Phenolic Composite System

NASA Technical Reports Server (NTRS)

Hou, Tan-Hung; Bai, J. M.; Baughman, James M.

2006-01-01

Phenolic resin systems generate water as a reaction by-product via condensation reactions during curing at elevated temperatures. In the fabrication of fiber reinforced phenolic resin matrix composites, volatile management is crucial in producing void-free quality laminates. A commercial vacuum-bag moldable phenolic prepreg system was selected for this study. The traditional single-vacuum-bag (SVB) process was unable to manage the volatiles effectively, resulting in inferior voidy laminates. However, a double vacuum bag (DVB) process was shown to afford superior volatile management and consistently yielded void-free quality parts. The DVB process cure cycle (temperature /pressure profiles) for the selected composite system was designed, with the vacuum pressure application point carefully selected, to avoid excessive resin squeeze-outs and achieve the net shape and target resin content in the final consolidated laminate parts. Laminate consolidation quality was characterized by optical photomicrography for the cross sections and measurements of mechanical properties. A 40% increase in short beam shear strength, 30% greater flexural strength, 10% higher tensile and 18% higher compression strengths were obtained in composite laminates fabricated by the DVB process.

Factors affecting marginal integrity of class II bulk-fill composite resin restorations

PubMed Central

Savadi Oskoee, Siavash; Bahari, Mahmoud; Jafari Navimipour, Elmira; Ajami, Amir Ahmad; Ghiasvand, Negar; Savadi Oskoee, Ayda

2017-01-01

Background. Bulk-fill composite resins are a new type of resin-based composite resins, claimed to have the capacity to be placed in thick layers, up to 4 mm. This study was carried out to evaluate factors affecting gap formation in Cl II cavities restored using the bulk-fill technique. Methods. A total of 60 third molars were used in this study. Two Cl II cavities were prepared in each tooth, one on the mesial aspect 1 mm coronal to the CEJ and one on the distal aspect 1 mm apical to the CEJ. The teeth were divided into 4 groups: A: The cavities were restored using the bulk-fill technique with Filtek P90 composite resin and its adhesive system and light-cured with quartz tungsten halogen (QTH) light-curing unit. B: The cavities were restored similar to that in group A but light-cured with an LED light-curing unit. C: The cavities were restored using the bulk-fill technique with X-tra Fil composite resin and Clearfil SE Bond adhesive system and light-cured with a QTH curing unit. D: The cavities were restored similar to that in group C but light-cured with an LED light-curing unit. The gaps were examined under a stereomicroscope at ×60. Data were analyzed with General Linear Model test. In cases of statistical significance (P<0.05), post hoc Bonferroni test was used for further analyses. Results. The light-curing unit type had no effect on gap formation. However, the results were significant in relation to the composite resin type and margin location (P<0.001). The cumulative effects of light-curing unit*gingival margin and light-curing unit*composite resin type were not significant; however, the cumulative effect of composite rein type*gingival margin was significant (P=0.04) Conclusion. X-tra Fil composite exhibited smaller gaps compared with Filtek P90 composite with both light-curing units. Both composite resins exhibited smaller gaps at enamel margins. PMID:28748051

Combinatorial Strategies for the Development of Bulk Metallic Glasses

NASA Astrophysics Data System (ADS)

Ding, Shiyan

The systematic identification of multi-component alloys out of the vast composition space is still a daunting task, especially in the development of bulk metallic glasses that are typically based on three or more elements. In order to address this challenge, combinatorial approaches have been proposed. However, previous attempts have not successfully coupled the synthesis of combinatorial libraries with high-throughput characterization methods. The goal of my dissertation is to develop efficient high-throughput characterization methods, optimized to identify glass formers systematically. Here, two innovative approaches have been invented. One is to measure the nucleation temperature in parallel for up-to 800 compositions. The composition with the lowest nucleation temperature has a reasonable agreement with the best-known glass forming composition. In addition, the thermoplastic formability of a metallic glass forming system is determined through blow molding a compositional library. Our results reveal that the composition with the largest thermoplastic deformation correlates well with the best-known formability composition. I have demonstrated both methods as powerful tools to develop new bulk metallic glasses.

Several vapor phase chemical treatments for dimensional stabilization of wood

Treesearch

H.M. Barnes; E.T. Choong; R.C. Mcllhenny

1969-01-01

A bench-scale system for the impregnation of wood with volatile compounds was constructed for the purpose of testing the system concept and evaluating various polymeric bulking materials as dimensional stabilizing agents. Provisions were incorporated for recycling the treating material, introduction of two separate materials alternately or simultaneously, timed-cycle...

Putative cryomagma interaction with aerosols deposit at Titan's surface

NASA Astrophysics Data System (ADS)

Coll, Patrice; Navarro-Gonzalez, Rafael; Raulin, Francois; Coscia, David; Ramirez, Sandra I.; Buch, Arnaud; Szopa, Cyril; Poch, Olivier; Cabane, Michel; Brassé, Coralie

The largest moon of Saturn, Titan, is known for its dense, nitrogen-rich atmosphere. The organic aerosols which are produced in Titan’s atmosphere are of great astrobiological interest, particularly because of their potential evolution when they reach the surface and may interact with putative ammonia-water cryomagma [1]. In this context we have followed the evolution of alkaline pH hydrolysis (25wt% ammonia-water) of Titan aerosol analogues, that have been qualified as representative of Titan’s aerosols [2]. Indeed the first results obtained by the ACP experiment onboard Huygens probe revealed that the main products obtained after thermolysis of Titan’s collected aerosols, were ammonia (NH3) and hydrogen cyanide (HCN). Then performing a direct comparison of the volatiles produced after a thermal treatment done in conditions similar to the ones used by the ACP experiment, we may estimate that the tholins we used are relevant to chemical analogues of Titan’s aerosols, and to note free of oxygen. Taking into account recent studies proposing that the subsurface ocean may contain a lower fraction of ammonia (about 5wt% or less [3]), and assuming the presence of specific gas species [4, 5], in particular CO2 and H2S, trapped in likely internal ocean, we determine a new probable composition of the cryomagma which could potentially interact with deposited Titan’s aerosols. We then carried out different hydrolyses, taking into account this composition, and we established the influence of the hydrolysis temperature on the organic molecules production. References: [1] Mitri et al., 2008. Resurfacing of Titan by ammonia-water cryomagma. Icarus. 196, 216-224. [2] Coll et al. 2013, Can laboratory tholins mimic the chemistry producing Titan's aerosols? A review in light of ACP experimental results, Planetary and Space Science 77, 91-103. [3] Tobie et al. 2012. Titan’s Bulk Composition Constrained by Cassini-Huygens: implication for internal outgassing. The Astrophysical Journal. 752, 125. [4] Hersant et al., 2004. Enrichment in volatiles in the giant planets of the Solar System. Planetary and Space Science. 52, 623-641. [5] Hersant et al., 2008. Interpretation of the carbon abundance in Saturn measured by Cassini. Planetary and Space Science. 56, 1103-1111.

Microbiology, biochemistry, and volatile composition of Tulum cheese ripened in goat's skin or plastic bags.

PubMed

Hayaloglu, A A; Cakmakci, S; Brechany, E Y; Deegan, K C; McSweeney, P L H

2007-03-01

Tulum cheeses were manufactured from raw ewe's milk and ripened in goat's skin bags (tulums) or plastic containers to understand the effect of ripening container on the chemical composition, biochemistry, microbiology, and volatile composition of Tulum cheeses during 150 d of ripening. Chemical compositions of the cheeses ripened in tulums were significantly different and the moisture contents decreased rapidly in those cheeses because of the porous structure of the tulum. Higher microbial counts were detected in the cheeses ripened in plastic than in cheeses ripened in tulums. Differences in nitrogenous compounds and total free AA of the cheeses were not significant. Total concentrations of free AA in cheeses increased with age and Glu, Ala, Val, Leu, and Phe were the most abundant AA in the cheeses. Urea-PAGE of pH 4.6-insoluble fractions of the cheeses during ripening showed similar degradation patterns in all cheeses. Peptide profiles by reversed-phase HPLC of pH 4.6- and ethanol-soluble or ethanol-insoluble fractions of the cheeses revealed only minor differences in the concentrations of some peptides among the cheeses; however, age-related changes in peptide concentrations were significantly different among the cheeses. Cheeses were analyzed at 90 d of ripening for volatile compounds by solid-phase microextraction gas chromatography-mass spectrometry. One hundred volatile components were identified, including 11 acids, 16 esters, 12 methyl ketones, 7 aldehydes, 22 alcohols, 7 sulfur compounds, 6 terpenes, and 19 miscellaneous compounds. The main components were short-chain fatty acids, 2-butanone, diacetyl, and primary alcohols. Quantitative differences in several volatile compounds were evident among the cheeses. Cheeses ripened in tulums or plastic had similar aroma patterns, but the concentrations of some components were different.

Time-varying volatility in Malaysian stock exchange: An empirical study using multiple-volatility-shift fractionally integrated model

NASA Astrophysics Data System (ADS)

Cheong, Chin Wen

2008-02-01

This article investigated the influences of structural breaks on the fractionally integrated time-varying volatility model in the Malaysian stock markets which included the Kuala Lumpur composite index and four major sectoral indices. A fractionally integrated time-varying volatility model combined with sudden changes is developed to study the possibility of structural change in the empirical data sets. Our empirical results showed substantial reduction in fractional differencing parameters after the inclusion of structural change during the Asian financial and currency crises. Moreover, the fractionally integrated model with sudden change in volatility performed better in the estimation and specification evaluations.

Biogenic, urban, and wildfire influences on the molecular composition of dissolved organic compounds in cloud water

NASA Astrophysics Data System (ADS)

Cook, Ryan D.; Lin, Ying-Hsuan; Peng, Zhuoyu; Boone, Eric; Chu, Rosalie K.; Dukett, James E.; Gunsch, Matthew J.; Zhang, Wuliang; Tolic, Nikola; Laskin, Alexander; Pratt, Kerri A.

2017-12-01

Organic aerosol formation and transformation occurs within aqueous aerosol and cloud droplets, yet little is known about the composition of high molecular weight organic compounds in cloud water. Cloud water samples collected at Whiteface Mountain, New York, during August-September 2014 were analyzed by ultra-high-resolution mass spectrometry to investigate the molecular composition of dissolved organic carbon, with a focus on sulfur- and nitrogen-containing compounds. Organic molecular composition was evaluated in the context of cloud water inorganic ion concentrations, pH, and total organic carbon concentrations to gain insights into the sources and aqueous-phase processes of the observed high molecular weight organic compounds. Cloud water acidity was positively correlated with the average oxygen : carbon ratio of the organic constituents, suggesting the possibility for aqueous acid-catalyzed (prior to cloud droplet activation or during/after cloud droplet evaporation) and/or radical (within cloud droplets) oxidation processes. Many tracer compounds recently identified in laboratory studies of bulk aqueous-phase reactions were identified in the cloud water. Organosulfate compounds, with both biogenic and anthropogenic volatile organic compound precursors, were detected for cloud water samples influenced by air masses that had traveled over forested and populated areas. Oxidation products of long-chain (C10-12) alkane precursors were detected during urban influence. Influence of Canadian wildfires resulted in increased numbers of identified sulfur-containing compounds and oligomeric species, including those formed through aqueous-phase reactions involving methylglyoxal. Light-absorbing aqueous-phase products of syringol and guaiacol oxidation were observed in the wildfire-influenced samples, and dinitroaromatic compounds were observed in all cloud water samples (wildfire, biogenic, and urban-influenced). Overall, the cloud water molecular composition depended on air mass source influence and reflected aqueous-phase reactions involving biogenic, urban, and biomass burning precursors.

Characterization of the KOI-273 Planetary System with HARPS-N

NASA Astrophysics Data System (ADS)

Gettel, Sara; Charbonneau, David; Harps-N Collaboration

2015-01-01

The NASA Kepler mission detected thousands of planets with radii between 1 and 3 Earth radii, a population with no analog in our own solar system. The composition of these objects is not yet well understood; some of these may be planets that are predominantly rocky and others may be planets with a large fractional composition of volatiles or a substantial hydrogen envelope. There are only seven planets smaller than 2.5 Re with published mass estimates with a precision better than 20%, the minimum required to distinguish between different compositional models.HARPS-N is an ultra-stable, fiber-fed, high-resolution spectrograph optimized for the measurement of very precise radial velocities. A primary goal of the HARPS-N collaboration is to measure precisely the masses of small transiting planets and so constrain their individual compositions.KOI-273 is a solar-like star (Teff = 5783, log(g) = 4.43, V = 11.68) with a 1.8 Earth-radius planet candidate in a 10.5-d orbit. During the 2014 Kepler observing season, we obtained 50 observations of this star, with a median photon-limited radial velocity precision of 1.9 m/s. Our data indicated the presence of an outer, massive companion. We present the orbital solution of this system and measure the bulk density and inferred composition of the inner planet.HARPS-N was funded by the Swiss Space Office, the Harvard Origin of Life Initiative, the Scottish Universities Physics Alliance, the University of Geneva, the Smithsonian Astrophysical Observatory, and the Italian National Astrophysical Institute, University of St. Andrews, Queens University Belfast, and University of Edinburgh. This work was made possible through a grant from the John Templeton Foundation.

Color Stability of the Bulk-Fill Composite Resins with Different Thickness in Response to Coffee/Water Immersion

PubMed Central

Sheikh-Al-Eslamian, Seyedeh Mahsa; Hasani, Elham; Abrandabadi, Ahmad Najafi

2016-01-01

We aimed to evaluate the color stability of bulk-fill and conventional composite resin with respect to thickness and storage media. Twenty specimens of a conventional composite resin (6 mm diameter and 2 mm thick) and 40 specimens of the bulk-fill Tetric EvoCeram composite resin at two different thicknesses (6 mm diameter and 2 mm thick or 4 mm thick, n = 20) were prepared. The specimens were stored in distilled water during the study period (28 d). Half of the specimens were remained in distilled water and the other half were immersed in coffee solution 20 min/d and kept in distilled water between the cycles. Color changes (ΔE) were measured using the CIE L ⁎ a ⁎ b ⁎ color space and a digital imaging system at 1, 7, 14, and 28 days of storage. Data were analyzed using Two-way ANOVA and Tukey's HSD post hoc test (P < 0.05). Composite resins showed significant increase in color changes by time (bulk-fill > conventional; P < 0.001). Coffee exhibited significantly more staining susceptibility than that of distilled water (P < 0.001). There was greater color changes with increasing the increment thickness, which was significant at 14 (P < 0.001) and 28 d (P < 0.01). Color change of bulk-fill composite resin was greater than that of the conventional one after coffee staining and is also a function of increment thicknesses. PMID:27403163

Physical properties and depth of cure of a new short fiber reinforced composite.

PubMed

Garoushi, Sufyan; Säilynoja, Eija; Vallittu, Pekka K; Lassila, Lippo

2013-08-01

To determine the physical properties and curing depth of a new short fiber composite intended for posterior large restorations (everX Posterior) in comparison to different commercial posterior composites (Alert, TetricEvoCeram Bulk Fill, Voco X-tra base, SDR, Venus Bulk Fill, SonicFill, Filtek Bulk Fill, Filtek Superme, and Filtek Z250). In addition, length of fiber fillers of composite XENIUS base compared to the previously introduced composite Alert has been measured. The following properties were examined according to ISO standard 4049: flexural strength, flexural modulus, fracture toughness, polymerization shrinkage and depth of cure. The mean and standard deviation were determined and all results were statistically analyzed with analysis of variance ANOVA (a=0.05). XENIUS base composite exhibited the highest fracture toughness (4.6MPam(1/2)) and flexural strength (124.3MPa) values and the lower shrinkage strain (0.17%) among the materials tested. Alert composite revealed the highest flexural modulus value (9.9GPa), which was not significantly different from XENIUS base composite (9.5GPa). Depth of cure of XENIUS base (4.6mm) was similar than those of bulk fill composites and higher than other hybrid composites. The length of fiber fillers in XENIUS base was longer (1.3-2mm) than in Alert (20-60μm). The new short fiber composite differed significantly in its physical properties compared to other materials tested. This suggests that the latter could be used in high-stress bearing areas. Copyright © 2013 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

H-Isotopic Composition of Apatite in Northwest Africa 7034

NASA Technical Reports Server (NTRS)

McCubbin, F. M.; Barnes, J. J.; Santos, A. R.; Boyce, J. W.; Anand, M.; Franchi, I. A.; Agee, C. B.

2016-01-01

Northwest Africa (NWA) 7034 and its pairings comprise a regolith breccia with a basaltic bulk composition [1] that yields a better match than any other martian meteorite to estimates of Mars' bulk crust composition [1]. Given the similarities between NWA 7034 and the martian crust, NWA 7034 may represent an important sample for constraining the crustal composition of components that cannot be measured directly by remote sensing. In the present study, we seek to constrain the H isotopic composition of the martian crust using Cl-rich apatite in NWA 7034.

A Campaign Study of Sea Spray Aerosol Properties in the Bay of Aarhus

NASA Astrophysics Data System (ADS)

Nguyen, Quynh; Rasmussen, Berit; Kristensen, Kasper; Sloth Nielsen, Lærke; Bilde, Merete

2016-04-01

The oceans of the world are a dominant source of atmospheric aerosol. Together with mineral dust, sea spray aerosols (SSA) constitute the largest mass flux of particulate matter in the atmosphere (Andreae and Rosenfeld, 2008). Due to their effects on the global radiative budget - both directly as scatterers and absorbers of solar and terrestrial radiation, and indirectly as cloud condensation nuclei (CCN), SSA are considered an important component of the climate system. The sea-surface microlayer (SML) is an ultra-thin boundary layer between the ocean and the atmosphere. The high concentration of surface-active organic compounds in the SML, compared to that of the underlying water column, creates rigid film-like layer over the surface of the ocean. The SML is believed to play an important role in the formation and composition of SSA. However, current knowledge on the SML and its impacts on SSA remain limited. To characterize the SML of natural seawater and examine its impacts on aerosol properties, a field campaign was conducted in the bay of Aarhus, Denmark, during spring 2015. Bulk seawater was collected 1-2 times every week along with selective sampling of the SML. Characterization of the sea water and SML included a wide range of measurements, including surface tension, water activity, dissolved organic matter, and chemical composition analysis by liquid chromatography/electrospray ionization high-resolution quadrupole time-of-flight mass spectrometry (UPLC/ESI-HR-Q-TOFMS). SSA was generated from sampled sea water by diffusion of air bubbles through a 10L seawater sample situated in a sea spray tank. Particle number concentration and CCN measurements were conducted along with measurements of the organic share in the aerosol phase as indicated by volatility measurements. To investigate the effect of the SML, spiking of the seawater samples with additional SML was performed and measurements repeated for comparison. Preliminary results show that the SML samples only displayed slightly lower surface tension compared to subsurface seawater. A number of overlapping masses were observed in dissolved organic matter extracted from SML and slick samples, which requires further identification. Spiking bulk seawater with SML seems to lead to a small increase in organic share in the aerosol phase as indicated by volatility measurements, while the trend is unclear in CCN measurements. Andreae, M. O., and Rosenfeld, D.: Aerosol-cloud-precipitation interactions. Part 1. The nature and sources of cloud-active aerosols, Earth-Sci Rev, 89, 13-41, 2008.

A young Moon-forming giant impact at 70-110 million years accompanied by late-stage mixing, core formation and degassing of the Earth.

PubMed

Halliday, Alex N

2008-11-28

New W isotope data for lunar metals demonstrate that the Moon formed late in isotopic equilibrium with the bulk silicate Earth (BSE). On this basis, lunar Sr isotope data are used to define the former composition of the Earth and hence the Rb-Sr age of the Moon, which is 4.48+/-0.02Ga, or 70-110Ma (million years) after the start of the Solar System. This age is significantly later than had been deduced from W isotopes based on model assumptions or isotopic effects now known to be cosmogenic. The Sr age is in excellent agreement with earlier estimates based on the time of lunar Pb loss and the age of the early lunar crust (4.46+/-0.04Ga). Similar ages for the BSE are recorded by xenon and lead-lead, providing evidence of catastrophic terrestrial degassing, atmospheric blow-off and significant late core formation accompanying the ca 100Ma giant impact. Agreement between the age of the Moon based on the Earth's Rb/Sr and the lead-lead age of the Moon is consistent with no major losses of moderately volatile elements from the Earth during the giant impact. The W isotopic composition of the BSE can be explained by end member models of (i) gradual accretion with a mean life of roughly 35Ma or (ii) rapid growth with a mean life of roughly 10Ma, followed by a significant hiatus prior to the giant impact. The former assumes that approximately 60 per cent of the incoming metal from impactors is added directly to the core during accretion. The latter includes complete mixing of all the impactor material into the BSE during accretion. The identical W isotopic composition of the Moon and the BSE limits the amount of material that can be added as a late veneer to the Earth after the giant impact to less than 0.3+/-0.3 per cent of ordinary chondrite or less than 0.5+/-0.6 per cent CI carbonaceous chondrite based on their known W isotopic compositions. Neither of these on their own is sufficient to explain the inventories of both refractory siderophiles such as platinum group elements and rhenium, and volatiles such as sulphur, carbon and water.

On volatile element trends in gas-rich meteorites

NASA Technical Reports Server (NTRS)

Bart, G.; Lipschutz, M. E.

1979-01-01

Ten volatile elements (and non-volatile Co) in co-existing light and dark portions of 5 gas-rich chondrites were studied. Patterns of distinct but non-uniform enrichment by dark admixing material are revealed. The dark admixing material is enriched in Cs; Bi and Tl covary in it. It is compositionally unique from known types of primitive materials and is apparently not derived by secondary processes from such materials.

Volatile composition and sensory properties of Vanilla × tahitensis bring new insights for vanilla quality control.

PubMed

Brunschwig, Christel; Rochard, Sophie; Pierrat, Alexandre; Rouger, Anne; Senger-Emonnot, Perrine; George, Gérard; Raharivelomanana, Phila

2016-02-01

Vanilla × tahitensis produced in French Polynesia has a unique flavour among vanilla species. However, data on volatiles and sensory properties remain limited. In this study, the volatile composition and sensory properties of V. × tahitensis from three Polynesian cultivars and two origins (French Polynesia/Papua New Guinea) were determined by gas chromatography-mass spectrometry and quantitative descriptive analysis, respectively, and compared to Vanilla planifolia. Vanilla species, origins and cultivars were differentiated by their volatile and sensory profiles using principal component analysis. The V. × tahitensis flavour from French Polynesia was characterized by a well-balanced sensory profile, having strong anise and caramel notes due to high levels of anisyl compounds. V. × tahitensis from Papua New Guinea was distinct from that of French Polynesia, having strong spicy, fruity, brown rum notes due to p-vinylguaiacol, p-cresol and esters. Vanilla planifolia showed stronger phenolic, woody, smoky notes due to guaiacol, creosol and phenol, which were found to be biomarkers of the species. Vanilla sensory properties were linked by partial least squares regression to key volatile compounds like guaiacol or creosol, which are indicators of lower quality. This study brings new insights to vanilla quality control, with a focus on key volatile compounds, irrespective of origin. © 2015 Society of Chemical Industry.

Amino Acid Profile and Volatile Flavour Compounds of Raw and Steamed Patin Catfish (Pangasius hypophthalmus) and Narrow-barred Spanish Mackerel (Scomberomorus commerson)

NASA Astrophysics Data System (ADS)

Pratama, Rusky I.; Rostini, I.; Rochima, E.

2018-02-01

Fish species and processing methods could affect the volatile flavour composition and amino acid profile of fishery commodity. The objectives of this study were to identify volatile components and amino acid profile of two considered predominant fish species in Indonesia which are freshwater Patin catfish (Pangasius hypophthalmus) and marine water fish, Spanish mackerel (Scomberomorus commerson). The methods used in this study were to detect volatile compounds using Gas Chromatography/Mass Spectrometry (GC/MS) on fresh and steamed of both species samples (100°C for 30 minutes) and amino acid profile were also analyzed using High Performance Liquid Chromatography (HPLC). The volatile components analysis successfully detects as much as 29 and 59 volatiles compounds in fresh and steamed Patin catfish respectively, while 37 and 102 compounds were detected in fresh and steamed Spanish mackerel samples. Most of detected components derives from hydrocarbons, aldehydes, alcohols and ketone groups which could affected by their chemical composition and resulted from various thermal involved reaction. The amino acids profile identification results showed that glutamic acid was found higher compared to other amino acids standards in both samples. Glutamic acid is non-essential amino acid which is important in umami taste substances.

Experimental constraints on the origin of high-Mg andesites: the effect of H2O and silica activity on mantle melt compositions

NASA Astrophysics Data System (ADS)

Moore, G. M.; Roggensack, K.

2009-12-01

Understanding the role volatiles (H2O, CO2) play in the origin of mantle-related melts is an important part of arc magma petrogenesis, and has implications for our understanding of many aspects of subduction zone volcanism including mass fluxes, volcanic degassing, and eruptive style. Both the occurrence of high-Mg andesites (HMA) in particular tectonic settings and their association with high H2O contents make HMA a unique window into hydrous subduction-related mantle melting processes. A significant amount of experimental work at mantle conditions has shown that increasing H2O content in the melt will not only stabilize olivine with respect to orthopyroxene, but will also increase the SiO2 content of the melt to andesitic amounts (e.g. Gaetani and Grove, 1998; Tatsumi, 1981; Tatsumi, 2006), suggesting that HMA could be a primary mantle melt if enough H2O is present. This hypothesis is supported by the rare occurrence of mantle xenoliths in Mg-rich andesites (Blatter and Carmichael, 1998; Tanaka and Aoki, 1981) that often contain hydrous mineral phases. Reliable thermodynamic modelling of such hydrous silicate melts in equilibrium with the mantle has proven difficult because of the relatively small set of experiments that allow this type of analysis. There are also experimental and analytical difficulties in dealing with hydrous high P-T samples (e.g. quench to a glass, rapid melt-solid reaction on quench, electron beam sensitivity of resulting glass, volatile content determination, etc), and statistical difficulties in determining robust model parameters because of the large degree of co-variance in the data set (e.g. T and H2O melt content). With the goal of addressing these problems, we conducted a series of “sandwich” type experiments at 1.0 GPa and 1200 deg C that saturated various hydrous melt compositions with olivine and opx. Our previous results have shown that the silica activity coefficient correlates negatively with H2O content (Moore and Roggensack, 2007), consistent with the earlier experimental phase equilibria results and the modeling of Carmichael (2002). New results using a broader range of starting melt compositions are presented here, showing that there is a significant effect of initial alkali content on the amount of melting of the mineral assemblage. This has the net result that the experimental melt compositions converge to a narrow range at high H2O contents that do not reproduce the observed HMA compositions, implying that the experimental P-T conditions used are not correct for generating HMA magmas. Use of this new data to thermodynamically model the influence of P, T, and melt composition (including H2O content) is underway, and will constrain whether hydrous arc lavas, including HMA, can be attributed to a primitive mantle origin, or whether other magmatic processes are necessary to generate their observed bulk compositions. It will also quantify the amount of H2O necessary to generate such magmas, giving insight into the potential H2O content present in the sub-arc mantle source regions, and allowing a more precise estimate of volatile fluxes in volcanic arc settings.

Magneto electric effects in BaTiO3-CoFe2O4 bulk composites

NASA Astrophysics Data System (ADS)

Agarwal, Shivani; Caltun, O. F.; Sreenivas, K.

2012-11-01

Influence of a static magnetic field (HDC) on the hysteresis and remanence in the longitudinal and transverse magneto electric voltage coefficients (MEVC) observed in [BaTiO3]1-x-[CoFe2O4]x bulk composites are analyzed. Remanence in MEVC at zero bias (HDC=0) is stronger in the transverse configuration over the longitudinal case. The observed hysteretic behavior in MEVC vs. HDC is correlated with the changes observed in the magnetostriction characteristics (λ and dλ/dH) reported for [BaTiO3]1-x-[CoFe2O4]x bulk composites.

Whole planet coupling between climate, mantle, and core: Implications for rocky planet evolution

NASA Astrophysics Data System (ADS)

Foley, Bradford J.; Driscoll, Peter E.

2016-05-01

Earth's climate, mantle, and core interact over geologic time scales. Climate influences whether plate tectonics can take place on a planet, with cool climates being favorable for plate tectonics because they enhance stresses in the lithosphere, suppress plate boundary annealing, and promote hydration and weakening of the lithosphere. Plate tectonics plays a vital role in the long-term carbon cycle, which helps to maintain a temperate climate. Plate tectonics provides long-term cooling of the core, which is vital for generating a magnetic field, and the magnetic field is capable of shielding atmospheric volatiles from the solar wind. Coupling between climate, mantle, and core can potentially explain the divergent evolution of Earth and Venus. As Venus lies too close to the sun for liquid water to exist, there is no long-term carbon cycle and thus an extremely hot climate. Therefore, plate tectonics cannot operate and a long-lived core dynamo cannot be sustained due to insufficient core cooling. On planets within the habitable zone where liquid water is possible, a wide range of evolutionary scenarios can take place depending on initial atmospheric composition, bulk volatile content, or the timing of when plate tectonics initiates, among other factors. Many of these evolutionary trajectories would render the planet uninhabitable. However, there is still significant uncertainty over the nature of the coupling between climate, mantle, and core. Future work is needed to constrain potential evolutionary scenarios and the likelihood of an Earth-like evolution.

Control of hydrocarbon emissions from gasoline loading by refrigeration systems. Final report Dec 80-Apr 81

DOE Office of Scientific and Technical Information (OSTI.GOV)

Battye, W.; Brown, P.; Misenheimer, D.

1981-07-01

The report gives results of a study of the capabilities of refrigeration systems, operated at three temperatures, to control volatile organic compound (VOC) emissions from truck loading at bulk gasoline terminals. Achievable VOC emission rates were calculated for refrigeration systems cooling various gasoline/air mixtures to -62 C, -73 C, and -84 C by estimating vapor/liquid equilibrium compositions for VOC/air mixtures. Emission rates were calculated for inlet streams containing vapors from low- and high-volatility gasolines at concentrations of 15, 30, and 50% by volume (22.5, 45, and 75% measured as propane). Predicted VOC emission rates for systems cooling various inlet streamsmore » to -62 C ranged from 48 to 59 mg VOC/liter of gasoline loaded. Predicted VOC were 21 to 28 mg/l loaded for systems operating at -73 C and 8.7 to 12 mg/l loaded for systems operating at -84 C. Compressor electrical requirements and relative capital costs for systems operating at the above temperatures were estimated for model systems using the results of a computer simulation. Compressor electrical requirements ranged from 0.11 to 0.45 Whr/l loaded, depending on the inlet VOC concentration and the outlet temperature. The capital cost to build a system designed to cool vapors to -84 C is estimated to be about 9% higher than for a system designed to operate at -73 C.« less

Rare earth element abundances in presolar SiC

NASA Astrophysics Data System (ADS)

Ireland, T. R.; Ávila, J. N.; Lugaro, M.; Cristallo, S.; Holden, P.; Lanc, P.; Nittler, L.; Alexander, C. M. O'D.; Gyngard, F.; Amari, S.

2018-01-01

Individual isotope abundances of Ba, lanthanides of the rare earth element (REE) group, and Hf have been determined in bulk samples of fine-grained silicon carbide (SiC) from the Murchison CM2 chondrite. The analytical protocol involved secondary ion mass spectrometry with combined high mass resolution and energy filtering to exclude REE oxide isobars and Si-C-O clusters from the peaks of interest. Relative sensitivity factors were determined through analysis of NIST SRM reference glasses (610 and 612) as well as a trace-element enriched SiC ceramic. When normalised to chondrite abundances, the presolar SiC REE pattern shows significant deficits at Eu and Yb, which are the most volatile of the REE. The pattern is very similar to that observed for Group III refractory inclusions. The SiC abundances were also normalised to s-process model predictions for the envelope compositions of low-mass (1.5-3 M⊙) AGB stars with close-to-solar metallicities (Z = 0.014 and 0.02). The overall trace element abundances (excluding Eu and Yb) appear consistent with the predicted s-process patterns. The depletions of Eu and Yb suggest that these elements remained in the gas phase during the condensation of SiC. The lack of depletion in some other moderately refractory elements (like Ba), and the presence of volatile elements (e.g. Xe) indicates that these elements were incorporated into SiC by other mechanisms, most likely ion implantation.

Elution of monomer from different bulk fill dental composite resins.

PubMed

Cebe, Mehmet Ata; Cebe, Fatma; Cengiz, Mehmet Fatih; Cetin, Ali Rıza; Arpag, Osman Fatih; Ozturk, Bora

2015-07-01

The purpose of this study was to evaluate the elution of Bis-GMA, TEGDMA, HEMA, and Bis-EMA monomers from six bulk fill composite resins over four different time periods, using HPLC. Six different composite resin materials were used in the present study: Tetric Evo Ceram Bulk Fill (Ivoclar Vivadent, Amherst, NY), X-tra Fill (VOCO, Cuxhaven, Germany), Sonic Fill (Kerr, Orange, CA, USA), Filtek Bulk Fill (3M ESPE Dental Product, St. Paul, MN), SDR (Dentsply, Konstanz, Germany), EQUIA (GC America INC, Alsip, IL). The samples (4mm thickness, 5mm diameter) were prepared and polymerized for 20s with a light emitted diode unit. After fabrication, each sample was immediately immersed in 75wt% ethanol/water solution used as extraction fluid and stored in the amber colored bottles at room temperature. Ethanol/water samples were taken (0.5mL) at predefined time intervals:10m (T1), 1h (T2), 24h (T3) and 30 days (T4). These samples were analyzed by HPLC. The obtained data were analyzed with one-way ANOVA and Tukey HSD at significance level of p<0.05. Amount of eluted Bis-EMA and Bis-GMA from Tetric Evo Ceram Bulk Fill and amount of eluted TEGDMA and HEMA from X-tra Fill higher than others composites (p<0.05). Residual monomers were eluted from bulk fill composite resins in all time periods and the amount of eluted monomers was increased with time. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Application of horizontal spiral coil heat exchanger for volatile organic compounds (VOC) emission control.

PubMed

Deshpande, P M; Dawande, S D

2013-04-01

The petroleum products have wide range of volatility and are required to be stored in bulk. The evaporation losses are significant and it is a economic as well as environmental concern, since evaporative losses of petroleum products cause increased VOC in ambient air. Control of these losses poses a major problem for the storage tank designers. Ever rising cost of petroleum products further adds to the gravity of the problem. Condensation is one of the technologies for reducing volatile organic compounds emissions. Condensation is effected by condenser, which is basically a heat exchanger and the heat exchanger configuration plays an important role. The horizontal spiral coil heat exchanger is a promising configuration that finds an application in VOC control. This paper attempts to understand underlying causes of emissions and analyse the option of horizontal spiral coil heat exchanger as vent condenser.

Compositional disorder and its effect on the thermoelectric performance of Zn₃P₂ nanowire-copper nanoparticle composites.

PubMed

Brockway, Lance; Vasiraju, Venkata; Vaddiraju, Sreeram

2014-03-28

Recent studies indicated that nanowire format of materials is ideal for enhancing the thermoelectric performance of materials. Most of these studies were performed using individual nanowires as the test elements. It is not currently clear whether bulk assemblies of nanowires replicate this enhanced thermoelectric performance of individual nanowires. Therefore, it is imperative to understand whether enhanced thermoelectric performance exhibited by individual nanowires can be extended to bulk assemblies of nanowires. It is also imperative to know whether the addition of metal nanoparticle to semiconductor nanowires can be employed for enhancing their thermoelectric performance further. Specifically, it is important to understand the effect of microstructure and composition on the thermoelectric performance on bulk compound semiconductor nanowire-metal nanoparticle composites. In this study, bulk composites composed of mixtures of copper nanoparticles with either unfunctionalized or 1,4-benzenedithiol (BDT) functionalized Zn₃P₂ nanowires were fabricated and analyzed for their thermoelectric performance. The results indicated that use of BDT functionalized nanowires for the fabrication of composites leads to interface-engineered composites that have uniform composition all across their cross-section. The interface engineering allows for increasing their Seebeck coefficients and electrical conductivities, relative to the Zn₃P₂ nanowire pellets. In contrast, the use of unfunctionalized Zn₃P₂ nanowires for the fabrication of composite leads to the formation of composites that are non-uniform in composition across their cross-section. Ultimately, the composites were found to have Zn₃P₂ nanowires interspersed with metal alloy nanoparticles. Such non-uniform composites exhibited very high electrical conductivities, but slightly lower Seebeck coefficients, relative to Zn₃P₂ nanowire pellets. These composites were found to show a very high zT of 0.23 at 770 K, orders of magnitude higher than either interface-engineered composites or Zn₃P₂ nanowire pellets. The results indicate that microstructural composition of semiconductor nanowire-metal nanoparticle composites plays a major role in determining their thermoelectric performance, and such composites exhibit enhanced thermoelectric performance.

Evaluation of HS-SPME and ultrasonic solvent extraction for monitoring of plant flavours added by the bees to herbhoneys: traceability biomarkers.

PubMed

Kuś, Piotr Marek; Marijanović, Zvonimir; Jerković, Igor

2015-01-01

The volatile composition of 21 herbhoneys (HHs) of 7 different botanical origins was characterised for the first time. Ultrasound solvent extraction (USE) and headspace solid-phase microextraction (HS-SPME) followed by GC-FID/MS were successfully applied as complementary methods for monitoring the volatile plant flavours added by the bees. HHs showed significant compositional variability related to the botanical origin and compounds that could serve as traceability biomarkers were identified. The most important compounds with high abundance were (E,extract; H, headspace): caffeine (up to 68.7%, E) and trans-linalool oxide (up to 26.0%, H) in coffee HH, α-terpineol (up to 8.2%, E; 27.1%, H) and bornyl acetate (up to 3.1, E; 11.9%, H) in pine HH, thymol (up to 3.1%, E; 55.4%, H) in thyme HH. Hawthorn HH was characterised by the presence of herniarin (up to 13.4%, E) and lemon HH contained limonene (up to 1.6%, E; 33.2%, H). Other HHs (nettle and aloe) contained lower amounts of volatiles and their profiles were not specific. In all the HHs, methyl syringate was found and it was most abundant in thyme HH (up to 17.4%, E). The volatile fraction of HHs showed some substantial similarities and differences with the composition of herbs from which they derive. It confirms the selective bee-mediated transfer of phytochemicals, including known flavour-active volatiles into the final product, but also biotransformation of several compounds. Additionally, several similarities to the corresponding natural honeys were observed, but in general HHs exhibited less rich volatile profiles.

Effects of chemical composition of fly ash on efficiency of metal separation in ash-melting of municipal solid waste

DOE Office of Scientific and Technical Information (OSTI.GOV)

Okada, Takashi, E-mail: t-okada@u-fukui.ac.jp; Tomikawa, Hiroki

2013-03-15

Highlights: ► Separation of Pb and Zn from Fe and Cu in ash-melting of municipal solid waste. ► Molar ratio of Cl to Na and K in fly ash affected the metal-separation efficiency. ► The low molar ratio and a non-oxidative atmosphere were better for the separation. - Abstract: In the process of metal separation by ash-melting, Fe and Cu in the incineration residue remain in the melting furnace as molten metal, whereas Pb and Zn in the residue are volatilized. This study investigated the effects of the chemical composition of incineration fly ash on the metal-separation efficiency of themore » ash-melting process. Incineration fly ash with different chemical compositions was melted with bottom ash in a lab-scale reactor, and the efficiency with which Pb and Zn were volatilized preventing the volatilization of Fe and Cu was evaluated. In addition, the behavior of these metals was simulated by thermodynamic equilibrium calculations. Depending on the exhaust gas treatment system used in the incinerator, the relationships among Na, K, and Cl concentrations in the incineration fly ash differed, which affected the efficiency of the metal separation. The amounts of Fe and Cu volatilized decreased by the decrease in the molar ratio of Cl to Na and K in the ash, promoting metal separation. The thermodynamic simulation predicted that the chlorination volatilization of Fe and Cu was prevented by the decrease in the molar ratio, as mentioned before. By melting incineration fly ash with the low molar ratio in a non-oxidative atmosphere, most of the Pb and Zn in the ash were volatilized leaving behind Fe and Cu.« less

New constraints on subduction inputs and volatile outputs along the Aleutian Arc

NASA Astrophysics Data System (ADS)

Lopez, T. M.; Fischer, T. P.; Plank, T. A.; Rizzo, A. L.; Rasmussen, D. J.; Cottrell, E.; Werner, C. A.; Kern, C.; Ilanko, T.; Buff, L.; Andrys, J.; Kelley, K. A.

2017-12-01

Volatile cycling drives volcanism in subduction zone settings. At arcs, volatiles can originate from the subducted slab, mantle wedge and/or crust. Each region has characteristic isotopic signatures, which can be used to fingerprint volatile provenance. We speculate that differences in subduction parameters, such as convergence angle, plate coupling and subducted sediment fluxes, may lead to differences in volatile provenance, which may in turn influence volcanic eruption style and frequency. Here we combine updated constraints on subduction inputs and volatile outputs to provide new insights into volatile cycling within the Aleutian Arc. The high proportion of organic carbon (80-100% to total carbon) in sediments subducting at the Aleutian trench stands out globally and predicts a light carbon isotopic composition of recycled volcanic fluids. We assess volatile outputs on volcanic timescales and along the arc by combining carbon (C), nitrogen (N) and helium (He) isotopic compositions of volcanic gases and new analyses of He and, where possible, C isotopes in olivine-hosted fluid inclusions. From our preliminary isotopic analyses of volcanic gases, we find a greater proportion of mantle-derived volatiles released from the Western segment of the Aleutian Arc (>40% mantle) compared with other volcanic arcs around the world (<30% mantle), where volatiles are sourced primarily from subducted or upper crustal carbonates. This trend may be due to the oblique convergence and low subducted sediment input in this region. The Aleutian Arc also exhibits among the lightest carbon isotope ratios of arcs worldwide (δ13C = -10 to -15‰), especially in the central part of the arc, where organic-bearing terrigneous sediment fills the trench and the convergence rate is high. New constraints on subduction inputs and outputs presented here will help discriminate between upper crustal and subducted carbon sources, and provide further insights into volatile cycling and subduction processes within the Aleutian Arc.

Photoperiod and aggression induce changes in ventral gland compounds exclusively in male Siberian hamsters.

PubMed

Rendon, Nikki M; Soini, Helena A; Scotti, Melissa-Ann L; Weigel, Ellen R; Novotny, Milos V; Demas, Gregory E

2016-05-01

Chemical communication is a critical component of social behavior as it facilitates social encounters, allows for evaluation of the social partner, defines territories and resources, and advertises information such as sex and physiological state of an animal. Odors provide a key source of information about the social environment to rodents; however, studies identifying chemical compounds have thus far focused primarily on few species, particularly the house mouse. Moreover, considerably less attention has been focused on how environmental factors, reproductive phenotype, and behavioral context alter these compounds outside of reproduction. We examined the effects of photoperiod, sex, and social context on chemical communication in the seasonally breeding Siberian hamster. We sampled ventral gland secretions in both male and female hamsters before and after an aggressive encounter and identified changes in a range of volatile compounds. Next, we investigated how photoperiod, reproductive phenotype, and aggression altered ventral gland volatile compound composition across the sexes. Males exhibited a more diverse chemical composition, more sex-specific volatiles, and showed higher levels of excretion compared to females. Individual volatiles were also differentially excreted across photoperiod and reproductive phenotype, as well as differentially altered in response to an aggressive encounter. Female volatile compound composition, in contrast, did not differ across photoperiods or in response to aggression. Collectively, these data contribute to a greater understanding of context-dependent changes in chemical communication in a seasonally breeding rodent. Copyright © 2016 Elsevier Inc. All rights reserved.

Effect of a cationic surfactant on the volatilization of PAHs from soil.

PubMed

Lu, Li; Zhu, Lizhong

2012-06-01

Cationic surfactants are common in soils because of their use in daily cosmetic and cleaning products, and their use as a soil amendment for the mitigation and remediation of organic contaminated soils has been proposed. Such surfactant may affect the transfer and fate of organic contaminants in the environment. This study investigated the effect of a cationic surfactant, dodecylpyridinium bromide (DDPB), on the volatilization of polycyclic aromatic hydrocarbons (PAHs) from a paddy soil. The volatilization of PAHs from moist soil amended with different concentrations of DDPB was tested in an open system. The specific effects of DDPB on the liquid-vapor and solid-vapor equilibriums of PAHs were separately investigated in closed systems by headspace analysis. DDPB affects both liquid-vapor and solid-vapor processes of PAHs in soil. At DDPB concentrations below the critical micelle concentration (CMC), movement of PAHs from the bulk solution to the gas-liquid interface appeared to be facilitated by interaction between PAHs and the surfactant monomers adsorbed at the gas-liquid interface, promoting the volatilization of PAHs from solution. However, when DDPB was greater than the CMC, volatilization was inhibited due to the solubilization of PAHs by micelles. On the other hand, the formation of sorbed surfactant significantly inhibited the solid-vapor volatilization of PAHs. The overall effect of the two simultaneous effects of DDPB on liquid-vapor and solid-vapor processes was a decreased volatilization loss of PAHs from soil. Inhibition of PAH volatilization was more significant for the soil with a lower moisture content.

Effect of Exogenous Abscisic Acid and Methyl Jasmonate on Anthocyanin Composition, Fatty Acids, and Volatile Compounds of Cabernet Sauvignon (Vitis vinifera L.) Grape Berries.

PubMed

Ju, Yan-Lun; Liu, Min; Zhao, Hui; Meng, Jiang-Fei; Fang, Yu-Lin

2016-10-12

The anthocyanin composition, fatty acids, and volatile aromas are important for Cabernet Sauvignon grape quality. This study evaluated the effect of exogenous abscisic acid (ABA) and methyl jasmonate (MeJA) on the anthocyanin composition, fatty acids, lipoxygenase activity, and the volatile compounds of Cabernet Sauvignon grape berries. Exogenous ABA and MeJA improved the content of total anthocyanins (TAC) and individual anthocyanins. Lipoxygenase (LOX) activity also increased after treatment. Furthermore, 16 fatty acids were detected. The linoleic acid concentration gradually increased with ABA concentration. The fatty acid content decreased with increasing MeJA concentration and then increased again, with the exception of linoleic acid. After exogenous ABA and MeJA treatment, the C6 aroma content increased significantly. Interestingly, the exogenous ABA and MeJA treatments improved mainly the content of 1-hexanol, hexanal, and 2-heptanol. These results provide insight into the effect of plant hormones on wine grapes, which is useful for grape quality improvement.

Fennel (Foeniculum vulgare Mill. subsp. piperitum) florets, a traditional culinary spice in Italy: evaluation of phenolics and volatiles in local populations, and comparison with the composition of other plant parts.

PubMed

Ferioli, Federico; Giambanelli, Elisa; D'Antuono, L Filippo

2017-12-01

Wild fennel (Foeniculum vulgare Mill. subsp. piperitum) florets are used as a typical spice in central and southern Italy. Although fennel (Foeniculum vulgare Mill.), belonging to the Apiaceae (syn. Umbelliferae) family, is a well-known vegetable and aromatic plant, whose main phytochemical compounds have been extensively analysed and investigated as flavouring agents and for their putative health promoting functions, its florets have not been specifically considered up to now. Therefore, the volatile and phenolic composition of florets from an Italian wild fennel crop was determined at different developmental stages, and compared to that of leaves and fruits. Moreover, florets of nine Italian wild fennel populations of different geographical origin from northern-central Italy were also analysed. The total phenolic amount increased from leaves to florets, reaching its highest value in early florets, at 58 012 mg kg -1 of dry matter (DM), then constantly decreased in fruits. In florets of wild populations, phenolics ranged from 6666 to 43 368 mg kg -1 DM. The total amount of volatile compounds was more than twice higher in florets (21 449 mg kg -1 DM) than in leaves (10 470 mg kg -1 DM), reaching its highest value in fruits (50 533 mg kg -1 DM). Estragole and trans-anethole were the main compounds of the volatile fraction. Total volatiles ranged from 24 367 to 60 468 mg kg -1 DM in florets of local populations. Significant changes in the total amount and profile of both phenolic and volatile compounds occurred during plant development. The consistent increase of estragole at later developmental stages supported the claim of different sensory properties of florets and fruits. Geographical origin significantly affected phenolic and volatile composition of wild fennel florets. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Osmium isotopic homogeneity in the CK carbonaceous chondrites

NASA Astrophysics Data System (ADS)

Goderis, Steven; Brandon, Alan D.; Mayer, Bernhard; Humayun, Munir

2017-11-01

Variable proportions of isotopically diverse presolar components are known to account for nucleosynthetic isotopic anomalies for a variety of elements (e.g., Ca, Ti, Cr, Ni, Sr, Zr, Mo, Ru, Pd, Ba, Nd, and Sm) in both bulk chondrites and achondrites. However, although large Os isotopic anomalies have been measured in acid leachates and residues of unequilibrated chondrites, bulk chondrites of various groups, iron meteorites, and pallasites exhibit Os isotopic compositions that are indistinguishable from terrestrial or bulk solar isotopic abundances. Since the magnitude of nucleosynthetic anomalies is typically largest in the carbonaceous chondrites, this study reports high-precision Os isotopic compositions and highly siderophile element (HSE) concentrations for ten CK chondrites. The isotope dilution concentration data for HSE and high-precision Os isotope ratios were determined on the same digestion aliquots, to precisely correct for radiogenic contributions to 186Os and 187Os. While acid leached bulk unequilibrated carbonaceous chondrites show deficits of s-process Os components to the same extent as revealed by unequilibrated enstatite, ordinary, and Rumuruti chondrites, equilibrated bulk CK chondrites exhibit no resolvable Os isotopic anomalies. These observations support the idea that acid-resistant, carbon-rich presolar grains, such as silicon carbide (SiC) or graphite, are major carriers for nucleosynthetic isotopic anomalies of Os. The destruction of these presolar grains, which are omnipresent in unequilibrated meteorites, must have occurred during aqueous alteration and thermal metamorphism, early in the CK chondrite parent body history. The dispersal of CK chondrites along the IIIAB iron meteorite isochron on a 187Os/188Os versus 187Re/188Os diagram, with Re/Os ratios from 0.032 to 0.083, in combination with the observed redistribution of other HSE (e.g., Pt, Pd), highlights the influence of parent body processes, overprinted by effects of recent terrestrial alteration. Under the oxidizing conditions prevalent on the CK parent body, evident from high abundances of magnetite and limited Fe-Ni metal in CK chondrites, these parent body processes made all isotopically anomalous Os, originally hosted in reduced presolar grains, accessible. The absence of Os isotopic anomalies in ordinary, enstatite, and now also carbonaceous chondrites, implies that the carriers of s- and r-process Os must have been effectively homogenized across the region of chondrite formation, and possibly even the entire solar protoplanetary nebula, as suggested by the Os isotopic compositions of iron meteorites and non-anomalous ureilites. Except for a limited number of ureilites, the relative proportions of presolar s- and r-process carriers of Os (and other elements such as W) in chondrites, and most other planetary bodies, must have remained constant during all subsequent nebular and planetary processes, which appears not to have been the case for other siderophile elements, including Mo, Ru, and Pd. The existence of Mo, Ru, Pd and other siderophile element isotopic anomalies thus appears to be in part controlled by the chemical properties of these elements (e.g., volatility), their host phase(s) (e.g., SiC, graphite, metal, sulfides), and the nature of the nebular or planetary processes experienced in the early solar system.

VOLATILE ORGANIC COMPOUND EMISSION RATES FROM MIXED DECIDUOUS AND CONIFEROUS FORESTS IN NORTHERN WISCONSIN, USA

EPA Science Inventory

Biogenic emissions of volatile organic compounds (VOC) from forests play an important role in regulating the atmospheric trace gas composition including global tropospheric ozone concentrations. However, more information is needed on VOC emission rates from different forest regio...

Distribution of Volatile Composition in 'Marion' (Rubus Species Hyb) Blackberry Pedigree

USDA-ARS?s Scientific Manuscript database

Fruit of 'Marion', as well as those of 'Marion's parents, grandparents, great grandparents and great-great grandparents that were available were evaluated for the volatiles that impact flavor. These various parents include blackberries from several species, raspberry and raspberry-blackberry hybrid...

Lunar Meteorites Sayh Al Uhaymir 449 and Dhofar 925, 960, and 961: Windows into South Pole

NASA Technical Reports Server (NTRS)

Ziegler, Ryan A.; Jolliff, B. L.; Korotev, R. L.

2013-01-01

In 2003, three lunar meteorites were collected in close proximity to each other in the Dhofar region of Oman: Dhofar 925 (49 g), Dhofar 960 (35 g), and Dhofar 961 (22 g). In 2006, lunar meteorite Sayh al Uhaymir (SaU) 449 (16.5 g) was found about 100 km to the NE. Despite significant differences in the bulk composition of Dhofar 961 relative to Dhofar 925/960 and SaU 449 (which are identical to each other), these four meteorites are postulated to be paired based on their find locations, bulk composition, and detailed petrographic analysis. Hereafter, they will collectively be referred to as the Dhofar 961 clan. Comparison of meteorite and component bulk compositions to Lunar Prospector 5-degree gamma-ray data suggest the most likely provenance of this meteorite group is within the South Pole-Aitken Basin. As the oldest, largest, and deepest recognizable basin on the Moon, the composition of the material within the SPA basin is of particular importance to lunar science. Here we review and expand upon the geochemistry and petrography of the Dhofar 961 clan and assess the likelihood that these meteorites come from within the SPA basin based on their bulk compositions and the compositions and characteristics of the major lithologic components found within the breccia.

40 CFR 79.2 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... combustion or other chemical or physical reaction. (d) Fuel manufacturer means any person who, for sale or... the chemical composition of a bulk fuel, or the mixture of chemical compounds in a bulk fuel, by... fuel. (h) Chemical composition means the name and percentage by weight of each compound in an additive...

Estimated content percentages of volatile liquids and fat extractables in ready-to-eat foods.

PubMed

Daft, J L; Cline, J K; Palmer, R E; Sisk, R L; Griffitt, K R

1996-01-01

Content percentages of volatile liquids and fat extractables in 340 samples of ready-to-eat foods were determined gravimetrically. Volatile liquids were determined by drying samples in a microwave oven with a self-contained balance; results were printed out automatically. Fat extractables were extracted from the samples with mixed ethers; extracts were dried and weighed manually. The samples, 191 nonfat and 149 fatty (containing ca 2% or more fat) foods, represent about 5000 different food items and include infant and toddler, ethnic, fast, and imported items. Samples were initially prepared for screening of essential and toxic elements and chemical contamination by chopping and mixing into homogenous composites. Content determinations were then made on separate portions from each composite. Content results were put into a database for evaluation. Overall, mean results from both determinations agree with published data for moisture and fat contents of similar food items. Coefficients of variation, however, were lower for determination of volatile liquids than for that of fat extractables.

Volatilization and mixing in glasses of some Apollo 14 regolith breccias

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vaniman, D.T.; Heiken, G.H.

1989-01-01

Three unique samples can be distinguished by analysis of all glass types, including devitrified glasses, in a suite of 26 Apollo 14 regolith breccias. These unique samples include the well-studied sample 14315, which has an abundance of anorthositic gabbro glasses and devitrified glasses; 14004,77, which has no glasses other than those that match the local soil; and 14076,5, which contains no glasses similar to the local soil or to LKFM. Sample 14076,5 is clearly exotic, for it contains devitrified glasses of anorthositic composition and of a silica-volatilized (HASP) trend that stems from anorthosite; these silica-volatilized glasses contain the new mineralmore » yoshiokite. HASP glasses in this exotic sample and HASP glass spheres that stem from the Apollo 14 soil composition differ greatly from the HASP glasses at Apollo 16. The various HASP glasses can be just as useful as non-volatilized glasses in searching or major crustal or regolith lithologies. 18 refs., 2 figs., 2 tabs.« less

Effect of different bulking agents on water variation and thermal balance and their respective contribution to bio-generated heat during long-term storage sludge biodrying process.

PubMed

Liu, Tiantian; Cui, Chongwei; He, Junguo; Tang, Jian

2018-04-17

Biodrying was first used for the post-treatment of long-term storage sludge with vinasse as bulking agents. The effect of different bulking agents on water and heat variation and their respective contributions to bio-generated heat during storage sludge biodrying were investigated. Three different bulking agents (beer lees and distillers grains, with conventional straw used for comparison) were mixed with storage sludge for biodrying for an 18-day period. The results revealed the treatment with beer lees as bulking agent achieved the best performance with the highest water removal capacity (658 g kg -1 initial water). The extent of organic degradation in the mixture was related to the degradation ability of the bulking agents. The degradation of C- and H-containing materials (e.g., carboxylic acid) accounted for volatile solids (VS) loss. Water and thermal analyses showed that evaporation was the main way of water loss (accounting for 90%), while evaporation heat was the main component of heat consumption (accounting for 56.67-60.62%).The biodegradation of bulking agents contributed a high proportion of the bio-generated heat consumed by water evaporation (82.35-86.67%).

Effects of Fibers on Color and Translucency Changes of Bulk-Fill and Anterior Composites after Accelerated Aging

PubMed Central

Güven, Mehmet Esad

2018-01-01

The aim of this study was to determine the effects of glass and polyethylene fibers on the color and translucency change of bulk-fill and anterior composites before and after artificial accelerated aging (AAA). Two types of teflon molds were used to fabricate samples which were 13 mm in diameter and, respectively, 2 mm and 4 mm in height. Polyethylene fiber (PF) and glass fiber (GF) were incorporated in the middle of the composite samples. Color and translucency changes of each composite were evaluated before and after AAA with spectrophotometer. ANOVA and Tukey's HSD post hoc statistical analysis were used at a significance level of 0.05. Before AAA (for anterior composites), there were no significant differences in L* and b* parameters among the three groups (p > 0.05); there were no significant differences in L* parameter between PF and GF groups or in TP between GF and control groups (p > 0.05) (for bulk-fill composites). After AAA, there were no significant differences in L* parameter between GF and control groups, in a* parameter between PF and control groups, in b* parameter among all groups, or in TP parameter between GF and control groups (p > 0.05). Fiber reinforcement led to color and TP change in both anterior and bulk-fill resin composites. PMID:29850499

Sintering Process and Mechanical Property of MWCNTs/HDPE Bulk Composite.

PubMed

Ming-Wen, Wang; Tze-Chi, Hsu; Jie-Ren, Zheng

2009-08-01

Studies have proved that increasing polymer matrices by carbon nanotubes to form structural reinforcement and electrical conductivity have significantly improved mechanical and electrical properties at very low carbon nanotubes loading. In other words, increasing polymer matrices by carbon nanotubes to form structural reinforcement can reduce friction coefficient and enhance anti-wear property. However, producing traditional MWCNTs in polymeric materix is an extremely complicated process. Using melt-mixing process or in situ polymerization leads to better dispersion effect on composite materials. In this study, therefore, to simplify MWCNTs /HDPE composite process and increase dispersion, powder was used directly to replace pellet to mix and sinter with MWCNTs. The composite bulks with 0, 0.5, 1, 2 and 4% nanotube content by weight was analyzed under SEM to observe nanotubes dispersion. At this rate, a MWCNTs/HDPE composite bulk with uniformly dispersed MWCNTs was achieved, and through the wear bench (Pin-on-Disk), the wear experiment has accomplished. Accordingly, the result suggests the sintered MWCNTs/HDPE composites amplify the hardness and wear-resist property.

(Chemotaxonomic) Implications of Postharvest/Storage-Induced Changes in Plant Volatile Profiles--the Case of Artemisia absinthium L. Essential Oil.

PubMed

Blagojević, Polina D; Radulović, Niko S; Skropeta, Danielle

2015-08-01

The plant volatile profile and the essential-oil chemical composition change during the storage of plant material. The objective of this study was to develop a mathematical model able to predict, explain, and quantify these changes. Mathematical equations, derived under the assumption that the essential oil contained within plant material could be treated as an ideal solution (Raoult's law), were applied for tracking of postharvest changes in the volatile profile of Artemisia absinthium L. (the essential oils were analyzed by GC-FID and GC/MS). Starting from a specific chemical composition of an essential-oil sample obtained from plant material after a short drying period (typically 5-10 d), and by using the equations derived from this model, one could easily predict evaporation-induced changes in the volatile profile of the plant material. Based on the composition of the essential-oil sample obtained after a given storage time t, it is possible to identify those components that were involved in chemical reactions, both as reactants and possible products. The established model even allowed the recognition of pairs of transformation, i.e., 'daughter' products and their 'parent' compounds. The obtained results highlight that the essential-oil composition is highly dependent on the storage period of any plant material and urges caution in different types of phytochemical studies, especially chemotaxonomic ones, or practical application. Copyright © 2015 Verlag Helvetica Chimica Acta AG, Zürich.

Trace element and Sr-Nd-Pb isotope geochemistry of Rungwe Volcanic Province, Tanzania: Implications for a superplume source for East Africa Rift magmatism

NASA Astrophysics Data System (ADS)

Castillo, Paterno; Hilton, David; Halldórsson, Sæmundur

2014-09-01

The recently discovered high, plume-like 3He/4He ratios at Rungwe Volcanic Province (RVP) in southern Tanzania, similar to those at the Main Ethiopian Rift in Ethiopia, strongly suggest that magmatism associated with continental rifting along the entire East African Rift System (EARS) has a deep mantle contribution (Hilton et al., 2011). New trace element and Sr-Nd-Pb isotopic data for high 3He/4He lavas and tephras from RVP can be explained by binary mixing relationships involving Early Proterozoic (+/- Archaean) lithospheric mantle, present beneath the southern EARS, and a volatile-rich carbonatitic plume with a limited range of compositions and best represented by recent Nyiragongo lavas from the Virunga Volcanic Province also in the Western Rift. Other lavas from the Western Rift and from the southern Kenya Rift can also be explained through mixing between the same endmember components. In contrast, lavas from the northern Kenya and Main Ethiopian rifts can be explained through variable mixing between the same mantle plume material and the Middle to Late Proterozoic lithospheric mantle, present beneath the northern EARS. Thus, we propose that the bulk of EARS magmatism is sourced from mixing among three endmember sources: Early Proterozoic (+/- Archaean) lithospheric mantle, Middle to Late Proterozoic lithospheric mantle and a volatile-rich carbonatitic plume with a limited range of compositions. We propose further that the African Superplume, a large, seismically anomalous feature originating in the lower mantle beneath southern Africa, influences magmatism throughout eastern Africa with magmatism at RVP and Main Ethiopian Rift representing two different heads of a single mantle plume source. This is consistent with a single mantle plume origin of the coupled He-Ne isotopic signatures of mantle-derived xenoliths and/or lavas from all segments of the EARS (Halldorsson et al., 2014).

Searching for Reduced Carbon on the Surface of Mars: The SAM Combustion Experiment

NASA Technical Reports Server (NTRS)

Stern, J. C.; Malespin, C. A.; Mahaffy, P. R.; Webster, C. R.; Eigenbrode, J. L.; Archer, P. D., Jr.; Brunner, A. E.; Freissinet, C.; Franz, H. B.; Glavin, D. P.;

The effect of bulk composition on the solidus of carbonated eclogite from partial melting experiments at 3 GPa

NASA Astrophysics Data System (ADS)

Dasgupta, Rajdeep; Hirschmann, Marc M.; Dellas, Nikki

2005-05-01

To explore the effect of bulk composition on the solidus of carbonated eclogite, we determined near-solidus phase relations at 3 GPa for four different nominally anhydrous, carbonated eclogites. Starting materials (SLEC1, SLEC2, SLEC3, and SLEC4) were prepared by adding variable proportions and compositions of carbonate to a natural eclogite xenolith (66039B) from Salt Lake crater, Hawaii. Near-solidus partial melts for all bulk compositions are Fe Na calcio-dolomitic and coexist with garnet + clinopyroxene + ilmenite ± calcio-dolomitic solid solution. The solidus for SLEC1 (Ca#=100 × molar Ca/(Ca + Mg + FeT)=32, 1.63 wt% Na2O, and 5 wt% CO2) is bracketed between 1,050°C and 1,075°C (Dasgupta et al. in Earth Planet Sci Lett 227:73 85, 2004), whereas initial melting for SLEC3 (Ca# 41, 1.4 wt% Na2O, and 4.4 wt% CO2) is between 1,175°C and 1,200°C. The solidus for SLEC2 (Ca# 33, 1.75 wt% Na2O, and 15 wt% CO2) is estimated to be near 1,100°C and the solidus for SLEC3 (Ca# 37, 1.47 wt% Na2O, and 2.2 wt% CO2) is between 1,100°C and 1,125°C. Solidus temperatures increase with increasing Ca# of the bulk, owing to the strong influence of the calcite magnesite binary solidus-minimum on the solidus of carbonate bearing eclogite. Bulk compositions that produce near-solidus crystalline carbonate closer in composition to the minimum along the CaCO3-MgCO3 join have lower solidus temperatures. Variations in total CO2 have significant effect on the solidus if CO2 is added as CaCO3, but not if CO2 is added as a complex mixture that maintains the cationic ratios of the bulk-rock. Thus, as partial melting experiments necessarily have more CO2 than that likely to be found in natural carbonated eclogites, care must be taken to assure that the compositional shifts associated with excess CO2 do not unduly influence melting behavior. Near-solidus dolomite and calcite solid solutions have higher Ca/(Ca + Mg) than bulk eclogite compositions, owing to Ca Mg exchange equilibrium between carbonates and silicates. Carbonates in natural mantle eclogite, which have low bulk CO2 concentration, will have Ca/Mg buffered by reactions with silicates. Consequently, experiments with high bulk CO2 may not mimic natural carbonated eclogite phase equilibria unless care is taken to ensure that CO2 enrichment does not result in inappropriate equilibrium carbonate compositions. Compositions of eclogite-derived carbonate melt span the range of natural carbonatites from oceanic and continental settings. Ca#s of carbonatitic partial melts of eclogite vary significantly and overlap those of partial melts of carbonated lherzolite, however, for a constant Ca-content, Mg# of carbonatites derived from eclogitic sources are likely to be lower than the Mg# of those generated from peridotite.

Northwest Africa 5738: Multistage fluid-driven secondary alteration in an extraordinarily evolved eucrite

NASA Astrophysics Data System (ADS)

Warren, Paul H.; Rubin, Alan E.; Isa, Junko; Gessler, Nicholas; Ahn, Insu; Choi, Byeon-Gak

2014-09-01

The Northwest Africa 5738 eucrite contains a record of unprecedented geochemical complexity for a sample from the HED asteroid. It originated with a uniquely evolved (Stannern Trend) primary igneous composition, combining ultra-high bulk incompatible element and Na2O concentrations with a relatively low mg. Its bulk oxygen-isotopic composition (Δ‧17O = -0.27‰), as well as its trace element composition (e.g., Ga/Al), confirm other evidence for classification as a eucrite. Pyroxene mg equilibration, exsolution and ;cloudy; inclusions, all reflect a typical eucritic degree of thermal metamorphism. The rock contains an unprecedented array of microscopic fluid-metasomatic vein deposits. Most common are curvy microveins within pyroxene, which consist dominantly of Ca-plagioclase (typically An95, in stark contrast with the rock's An68-78 primary-igneous plagioclase), with Fe-olivine (Fo14) and Cr-spinel as additional major constituents. Likely related to these microveins are small masses of intergrown Ca-plagioclase (again roughly An95) and silica (or high-Si glass). Analyses of the microvein Cr-spinels show stoichiometry implying a significant Fe3+ content (Fe2O3 0.7-2.3 wt.%), and fO2 up to roughly IW+3; clearly elevated in comparison to the normal HED fO2 of about IW-1. The fO2 results show an anticorrelation with equilibration T (and with Mg/Fe), which suggests the parent fluid system became more oxidizing as it cooled. NWA 5738 also contains apparent secondary iron metal. The Fe-metals are very pure, with Ni consistently below an EPMA detection limit of ∼0.01 wt.%. The vein-like shapes of roughly 1/3 of the largest Fe-metals suggest origin by deposition from a fluid. The role of pyroxene exsolution as template for a denticular (sawtooth) Fe-metal edge shape, and the survival of Fo14 olivine in a rock with abundant silica and a far higher bulk mg, suggest that the most intense thermal metamorphism occurred no later than the secondary alteration. Near-complete lack of spatial association suggests that the Fe-metals formed during a distinct time period from the curvy microveins. The immediate cause of Fe-metal deposition was most plausibly (or anyway, least implausibly) an abrupt downshift in the fluid fO2. Considering the extremely evolved bulk composition, the fluid(s) may have been largely deuteric. However, more likely the main source of fluid was a nearby buried mass of volatile-rich impactor matter, such as carbonaceous chondrite, that hit the asteroid at low enough velocity to remain mostly intact. We further speculate that the abrupt drop in fluid fO2 may have been caused by a process of carbon-fueled ;smelting; (cf. ureilites), triggered by an impact-effected shift of the carbonaceous material to a changed environment, with higher T and/or lower P. These and other recent eucrite results point to a need for greater scrutiny regarding the absence of comparable alteration-veining in rocks from the lunar highland crust, a mysterious lack in view of recent evidence for abundant lunar water.

Headspace-Solid-Phase Microextraction-Gas Chromatography as Analytical Methodology for the Determination of Volatiles in Wild Mushrooms and Evaluation of Modifications Occurring during Storage

PubMed Central

Costa, Rosaria; De Grazia, Selenia; Grasso, Elisa; Trozzi, Alessandra

2015-01-01

Mushrooms are sources of food, medicines, and agricultural means. Not much is reported in the literature about wild species of the Mediterranean flora, although many of them are traditionally collected for human consumption. The knowledge of their chemical constituents could represent a valid tool for both taxonomic and physiological characterizations. In this work, a headspace-solid-phase microextraction (HS-SPME) method coupled with GC-MS and GC-FID was developed to evaluate the volatile profiles of ten wild mushroom species collected in South Italy. In addition, in order to evaluate the potential of this analytical methodology for true quantitation of volatiles, samples of the cultivated species Agaricus bisporus were analyzed. The choice of this mushroom was dictated by its ease of availability in the food market, due to the consistent amounts required for SPME method development. For calibration of the main volatile compounds, the standard addition method was chosen. Finally, the assessed volatile composition of A. bisporus was monitored in order to evaluate compositional changes occurring during storage, which represents a relevant issue for such a wide consumption edible product. PMID:25945282

Effect of storage under extremely low oxygen on the volatile composition of 'Royal Gala' apples.

PubMed

Both, Vanderlei; Brackmann, Auri; Thewes, Fabio Rodrigo; Ferreira, Daniele de Freitas; Wagner, Roger

2014-08-01

The aim of this work was to assess the profile of volatile compounds in 'Royal Gala' apples stored under controlled atmosphere (CA), with O(2) levels ranging from 1.0kPa to as low as 0.5kPa during 8months (0.5°C), followed by 7days of shelf-life at 20°C. Volatile compounds were collected via solid-phase microextraction (HS-SPME) and analysed by gas chromatography. Straight and branched-chain esters exhibited a distinct pattern. The emission of straight-chain esters decreased under extremely low O(2) (0.5kPa), while branched-chain esters were not significantly affected in such condition. 2-Methyl-butyl acetate, a significant contributor to the 'Royal Gala' aroma, was higher in intermediate O(2) concentration, suggesting that lowering the O(2) levels down to 0.7kPa does not negatively affect the volatile composition of 'Royal Gala' apples, as compared to the standard CA (1.0kPa O(2)). The remaining volatile compounds were not strongly affected by storing fruits under extremely low O(2). Copyright © 2014 Elsevier Ltd. All rights reserved.

Simulation of radioelement volatility during the vitrification of radioactive wastes by arc plasma.

PubMed

Ghiloufi, Imed

2009-04-15

A computer model is used to simulate the volatility of some radioelements cesium ((137)Cs), cobalt ((60)Co), and ruthenium ((106)Ru) during the radioactive wastes vitrification by thermal plasma. This model is based on the calculation of system composition using the free enthalpy minimization method, coupled with the equation of mass transfer at the reactional interface. The model enables the determination of the effects of various parameters (e.g., temperature, plasma current, and matrix composition) on the radioelement volatility. The obtained results indicate that any increase in molten bath temperature causes an increase in the cobalt volatility; while ruthenium has a less obvious behavior. It is also found that the oxygen flux in the carrier gas supports the radioelement incorporations in the containment matrix, except in the case of the ruthenium which is more volatile under an oxidizing atmosphere. For electrolyses effects, an increase in the plasma current considerably increases both the vaporization speed and the vaporized quantities of (137)Cs and (60)Co. The increase of silicon percentage in the containment matrix supports the incorporation of (60)Co and (137)Cs in the matrix. The simulation results are compared favorably to the experimental measurements obtained by emission spectroscopy.

Orientation to determine quality attributes of flavoring excipients containing volatile molecules.

PubMed

Kiene, Florian E; Pein, Miriam; Thommes, Markus

2015-06-10

Pharmaceutical excipients containing volatile odor-active molecules can be used in pharmaceutical development to increase patients' compliance. However, capturing the molecular composition of these odor-active substances is challenging. Therefore, guidance for the analytical investigation of these excipients should be developed. Using a model flavor, lead molecules were chosen and a gas chromatographic method was validated according to pharmaceutical guidelines. Changes during storage as well as batch homogeneity and conformity were investigated. The knowledge gained could be used to understand molecular differences between batches caused by aging. A suitable attempt to capture the volatile molecular composition of flavoring substance was presented and the found results could be used for the determination and interpretation of quality attributes. Copyright © 2015 Elsevier B.V. All rights reserved.

Profiling of volatile fragrant components in a mini-core collection of mango germplasms from seven countries

PubMed Central

Zhan, Ru-Lin; Wu, Hong-Xia; Yao, Quan-Sheng; Xu, Wen-Tian; Luo, Chun; Zhou, Yi-Gang; Liang, Qing-Zhi; Wang, Song-Biao

2017-01-01

Aroma is important in assessing the quality of fresh fruit and their processed products, and could provide good indicators for the development of local cultivars in the mango industry. In this study, the volatile diversity of 25 mango cultivars from China, America, Thailand, India, Cuba, Indonesia, and the Philippines was investigated. The volatile compositions, their relative contents, and the intervarietal differences were detected with headspace solid phase microextraction tandem gas chromatography-mass spectrometer methods. The similarities were also evaluated with a cluster analysis and correlation analysis of the volatiles. The differences in mango volatiles in different districts are also discussed. Our results show significant differences in the volatile compositions and their relative contents among the individual cultivars and regions. In total, 127 volatiles were found in all the cultivars, belonging to various chemical classes. The highest and lowest qualitative abundances of volatiles were detected in ‘Zihua’ and ‘Mallika’ cultivars, respectively. Based on the cumulative occurrence of members of the classes of volatiles, the cultivars were grouped into monoterpenes (16 cultivars), proportion and balanced (eight cultivars), and nonterpene groups (one cultivars). Terpene hydrocarbons were the major volatiles in these cultivars, with terpinolene, 3-carene, caryophyllene and α-Pinene the dominant components depending on the cultivars. Monoterpenes, some of the primary volatile components, were the most abundant aroma compounds, whereas aldehydes were the least abundant in the mango pulp. β-Myrcene, a major terpene, accounted for 58.93% of the total flavor volatile compounds in ‘Xiaofei’ (Philippens). γ-Octanoic lactone was the only ester in the total flavor volatile compounds, with its highest concentration in ‘Guiya’ (China). Hexamethyl cyclotrisiloxane was the most abundant volatile compound in ‘Magovar’ (India), accounting for 46.66% of the total flavor volatiles. A typical aldehydic aroma 2,6-di-tert-butyl-4-sec-butylphenol, was detected in ‘Gleck’. A highly significant positive correlation was detected between Alc and K, Alk and Nt, O and L. Cultivars originating from America, Thailand, Cuba, India, Indonesia and the Philippines were more similar to each other than to those from China. This study provides a high-value dataset for use in development of health care products, diversified mango breeding, and local extension of mango cultivars. PMID:29211747

Volatile element content of the heterogeneous upper mantle

NASA Astrophysics Data System (ADS)

Shimizu, K.; Saal, A. E.; Hauri, E. H.; Forsyth, D. W.; Kamenetsky, V. S.; Niu, Y.

2014-12-01

The physical properties of the asthenosphere (e.g., seismic velocity, viscosity, electrical conductivity) have been attributed to either mineral properties at relevant temperature, pressure, and water content or to the presence of a low melt fraction. We resort to the geochemical studies of MORB to unravel the composition of the asthenosphere. It is important to determine to what extent the geochemical variations in axial MORB do represent a homogeneous mantle composition and variations in the physical conditions of magma generation and transport; or alternatively, they represent mixing of melts from a heterogeneous upper mantle. Lavas from intra-transform faults and off-axis seamounts share a common mantle source with axial MORB, but experience less differentiation and homogenization. Therefore they provide better estimates for the end-member volatile budget of the heterogeneous upper mantle. We present major, trace, and volatile element data (H2O, CO2, Cl, F, S) as well as Sr, Nd, and Pb isotopic compositions [1, 2] of basaltic glasses (MgO > 6.0 wt%) from the NEPR seamounts, Quebrada-Discovery-Gofar transform fault system, and Macquarie Island. The samples range from incompatible trace element (ITE) depleted (DMORB: Th/La<0.035) to enriched (EMORB: Th/La>0.07) spanning the entire range of EPR MORB. The isotopic composition of the samples correlates with the degree of trace element enrichment indicating long-lived mantle heterogeneity. Once shallow-level processes (degassing, crystallization, and crustal assimilation) have been considered, we conducted a two-component (DMORB- and EMORB-) mantle melting-mixing model. Our model reproduces the major, trace and volatile element contents and isotopic composition of our samples and suggests that (1) 90% of the upper mantle is highly depleted in ITE (DMORB source) with only 10% of an enriched component (EMORB source), (2) the EMORB source is peridotitic rather than pyroxenitic, and (3) NMORB do not represent an actual mantle source, but the product of magma mixing between D- and E-MORB. Finally we use the volatile to trace element ratios of our samples to estimate the volatile element budget of the end-member components of the upper mantle. [1] Niu, Y. et al. (2002) EPSL, 199, 327-345. [2] Kamenetsky, V. S. et al. (2000) J. Petrology, 41, 411-430.

Analysis of Surface and Bulk Behavior in Ni-Pd Alloys

NASA Technical Reports Server (NTRS)

Bozzolo, Guillermo; Noebe, Rondald D.

2003-01-01

The most salient features of the surface structure and bulk behavior of Ni-Pd alloys have been studied using the BFS method for alloys. Large-scale atomistic simulations were performed to investigate surface segregation profiles as a function of temperature, crystal face, and composition. Pd enrichment of the first layer was observed in (111) and (100) surfaces, and enrichment of the top two layers occurred for (110) surfaces. In all cases, the segregation profile shows alternate planes enriched and depleted in Pd. In addition, the phase structure of bulk Ni-Pd alloys as a function of temperature and composition was studied. A weak ordering tendency was observed at low temperatures, which helps explain the compositional oscillations in the segregation profiles. Finally, based on atom-by-atom static energy calculations, a comprehensive explanation for the observed surface and bulk features will be presented in terms of competing chemical and strain energy effects.

The Shallow Plumbing System of Piton de la Fournaise Volcano (La Réunion island, Indian Ocean) Revealed by the Major 2007 Caldera Forming Eruption (Invited)

NASA Astrophysics Data System (ADS)

Di Muro, A.; Metrich, N.; Daniele, V.; Rosi, M.; Armienti, P.; Fougeroux, T.; Deloule, E.; Arienzo, I.; Civetta, L.

2013-12-01

The 2007 eruption represents a major event in the recent history of Piton de la Fournaise volcano because it produced: i) the most voluminous lava field (at least 0.21 km3), ii) the most intense lava fountaining activity (>200 m high), iii) the largest SO2 plume (>230 kt), iv) the largest summit collapse (1 km wide x 0.34 km deep) and v) the main flank slip event (up to 1.4 m eastwards) ever documented at PdF. The bulk magma volume extruded during the 2007 eruptive sequence is similar to that emitted during the entire 1998-2006 period. As a whole, the volume of magma emitted during the whole 1998-2007 activity cycle is remarkably close to that estimated (~0.35 km3) for the shallow plumbing system of Piton de la Fournaise. The 2007 eruptive sequence consisted of three successive phases (February, March and April). The main caldera forming phase of April ended a 9 years long period (1998-2007) of continuous edifice inflation and frequent eruptive activity (3 eruptions per year on average). On the contrary, post-2007 activity punctuates a trend of continuous deflation and consists of small-volume summit eruptions of moderate/low MgO magmas and frequent shallow magma intrusions. The 2007 lavas and pyroclasts cover the complete range of textures and crystal content an composition typically found in PdF products. The broad range of textures and the large volumes of pyroclasts, lava and gas emitted in 2007 provide an unique and exceptional record of the time-integrated evolution of PdF magma, and represent an unique opportunity to image the volcano plumbing system and bring new constraints on the processes controlling its magmatic and volatile budget. We here address these issues by using an unprecedented geochemical dataset (major, volatile and trace elements, Sr-Nd isotopes) on bulk rocks, minerals, glass inclusions and glass matrices from a very detailed sample set, representative of the time evolution of extruded magma during the entire 2007 eruptive sequence.

Novel sampling methods for atmospheric semi-volatile organic compounds (SOCs) in a high altitude alpine environment.

PubMed

Offenthaler, I; Jakobi, G; Kaiser, A; Kirchner, M; Kräuchi, N; Niedermoser, B; Schramm, K-W; Sedivy, I; Staudinger, M; Thanner, G; Weiss, P; Moche, W

2009-12-01

High- and low-volume active air samplers as well as bulk deposition samplers were developed to sample atmospheric SOCs under the adverse conditions of a mountain environment. Active sampling employed separate filters for different European source regions. Filters were switched depending on daily trajectory forecasts, whose accuracy was evaluated post hoc. The sampling continued on three alpine summits over five periods of four months. The prevailing trajectories varied stronger between sampling periods than between stations. The sampling equipment (active and bulk deposition) proved dependable for operation in a mountain environment, with idle times being mainly due to non-routine manipulations and connectivity.

Bulk functionalization of graphene using diazonium compounds and amide reaction

NASA Astrophysics Data System (ADS)

Peng, Chang; Xiong, Yuzi; Liu, Zhibo; Zhang, Fan; Ou, Encai; Qian, Jiangtao; Xiong, Yuanqin; Xu, Weijian

2013-09-01

An efficient and convenient method is applied to introduce varieties of simple functionalities onto the graphene surface for the bulk preparation, which begins with pristine graphite that does not require initial oxidative damage of the graphene basal planes. Diazonium compounds functionalized reaction is demonstrated and it successfully prevented the aggregation of graphene for which providing solubility in high polar organic media or even in volatile solvents such as ethanol and acetone. This approach is complemented by the phenyl carboxylic diazonium salt functionalized graphene (PCFG) attachment of a symmetrically substituted zinc phthalocyanine (PCFG-Pc) using the amide reaction, which is used for the covalent introduction of a complex phthalocyanine molecule.

Evaluation of Vickers hardness of bulk-fill composites cured by different light sources

NASA Astrophysics Data System (ADS)

Bakhsh, Turki A.; Yagmoor, Mohammed A.; Alsadi, Fahad M.; Jamleh, Ahmad

2016-02-01

[Objective] The current in vitro study was performed to evaluate Vickers hardness (VHN) of two different composite resins that were cured by using two different light curing units. [Materials and Methods] Porcelain tube samplers were used to fabricate composite cylinders from either Tetric Evoceram BulkFill (BF; Ivoclar/Vivadent, USA) or SonicFill composite (SF; Kerr, USA). Each composite type had 12 cylindrical specimens, and each specimen was cured with either Blue-phase N light-cure (Bp; Polywave, Ivoclar/Vivadent, USA) or Elipar S10 (El; Monowave, 3M ESPE, Germany). The VHN data were analyzed and tested by using Mann-Whitney U test at a significance level of 5%. [Results] Statistical analyses demonstrated an interaction between the type of composite and the type of light curing source. Significant differences (P<0.05) were recorded for all groups with higher VHN hardness of SF-El and lowest for BF-El. [Conclusions] It can be concluded that the surface hardness of bulk-fill composite is not dependent on the type of light-cure. This research was supported by King Abdulaziz University.

High Precision Iron Isotope Compositions in Components From the Allende CV3 Meteorite by MC-ICP-MS

NASA Astrophysics Data System (ADS)

Mullane, E.; Russell, S. S.; Weiss, D.; Mason, T. F.; Gounelle, M.

2001-12-01

Four chondrules and one matrix sample of Allende were examined for Fe-isotope frac-tionation, using multi-collector inductively coupled plasma mass spectrometry (MC-ICPMS). Iron is the most volatile major constituent of chondrules and a recent study [1] suggested that solar system Fe was initially isotopically homogeneous. Thus, any isotopic variation is likely due to mass fractionation during nebular process-ing. The chondrule samples were split. One portion was subject to a standard acid dis-solution whilst the other was polished, ena-bling textural and compositional characteri-zation. Fe, Cu and Zn are separated from the remaining matrix elements [2], removing potential interfering ions from the solution. 100 % elemental recovery (within error) is achieved, ensuring that chromatographic fractionation does not occur [2]. Hydrogen is bled into the collision cell, minimising Ar polyatomic species interferences. Typical precisions of 0.1‰ (2σ ) for 54Fe/56Fe ratios are achieved for 75 replicates. Instrumental mass bias is assessed using (1) sample-standard brack-eting and (2) doping with Cu. A variation of 0.8‰ /amu is observed, which is approximately 18 times the analyti-cal uncertainty at the 2σ level. Our high precision data show that: (1) Allende chondrules and matrix exhibit clear isotopic variation in iron. (2) δ 54Fe val-ues appear to be correlated to the bulk FeO content, with the more iron rich samples enriched in the lighter 54Fe isotope. (3) δ 54Fe values appear to be unre-lated to texture, and consequently to the temperature of chondrule formation. Bulk Fe-content may be a proxy for the amount of volatilisation experienced, and volatilisation of Fe in chondrule precursor material has resulted in a residue of the heavier Fe isotopes. Chondrules are known to have often experienced several heating events, and their texture primarily reflects the nature of the last event. Thus, the lack of correlation between the δ 54Fe value and chondrule texture suggests that Fe-isotope composi-tion was derived from chondrule precursor material. [1] Zhu et al. (2001) Nature 412, p.311 [2] Mullane et al. (2001) LPS XXXII, No.1545.

Hydrothermal Habitats: Measurements of Bulk Microbial Elemental Composition, and Models of Hydrothermal Influences on the Evolution of Dwarf Planets

NASA Astrophysics Data System (ADS)

Neveu, Marc Francois Laurent

Finding habitable worlds is a key driver of solar system exploration. Many solar system missions seek environments providing liquid water, energy, and nutrients, the three ingredients necessary to sustain life. Such environments include hydrothermal systems, spatially-confined systems where hot aqueous fluid circulates through rock by convection. I sought to characterize hydrothermal microbial communities, collected in hot spring sediments and mats at Yellowstone National Park, USA, by measuring their bulk elemental composition. To do so, one must minimize the contribution of non-biological material to the samples analyzed. I demonstrate that this can be achieved using a separation method that takes advantage of the density contrast between cells and sediment and preserves cellular elemental contents. Using this method, I show that in spite of the tremendous physical, chemical, and taxonomic diversity of Yellowstone hot springs, the composition of microorganisms there is surprisingly ordinary. This suggests the existence of a stoichiometric envelope common to all life as we know it. Thus, future planetary investigations could use elemental fingerprints to assess the astrobiological potential of hydrothermal settings beyond Earth. Indeed, hydrothermal activity may be widespread in the solar system. Most solar system worlds larger than 200 km in radius are dwarf planets, likely composed of an icy, cometary mantle surrounding a rocky, chondritic core. I enhance a dwarf planet evolution code, including the effects of core fracturing and hydrothermal circulation, to demonstrate that dwarf planets likely have undergone extensive water-rock interaction. This supports observations of aqueous products on their surfaces. I simulate the alteration of chondritic rock by pure water or cometary fluid to show that aqueous alteration feeds back on geophysical evolution: it modifies the fluid antifreeze content, affecting its persistence over geological timescales; and the distribution of radionuclides, whose decay is a chief heat source on dwarf planets. Interaction products can be observed if transported to the surface. I simulate numerically how cryovolcanic transport is enabled by primordial and hydrothermal volatile exsolution. Cryovolcanism seems plausible on dwarf planets in light of images recently returned by spacecrafts. Thus, these coupled geophysical-geochemical models provide a comprehensive picture of dwarf planet evolution, processes, and habitability.

Fracture resistance of endodontically treated teeth restored with a bulkfill flowable material and a resin composite

PubMed Central

Isufi, Almira; Plotino, Gianluca; Grande, Nicola Maria; Ioppolo, Pietro; Testarelli, Luca; Bedini, Rossella; Al-Sudani, Dina; Gambarini, Gianluca

2016-01-01

Summary Aim To determine and compare the fracture resistance of endodontically treated teeth restored with a bulk fill flowable material (SDR) and a traditional resin composite. Methods Thirty maxillary and 30 mandibular first molars were selected based on similar dimensions. After cleaning, shaping and filling of the root canals and adhesive procedures, specimens were assigned to 3 subgroups for each tooth type (n=10): Group A: control group, including intact teeth; Group B: access cavities were restored with a traditional resin composite (EsthetX; Dentsply-Italy, Rome, Italy); Group C: access cavities were restored with a bulk fill flowable composite (SDR; Dentsply-Italy), except 1.5 mm layer of the occlusal surface that was restored with the same resin composite as Group B. The specimens were subjected to compressive force in a material static-testing machine until fracture occurred, the maximum fracture load of the specimens was measured (N) and the type of fracture was recorded as favorable or unfavorable. Data were statistically analyzed with one-way analysis of variance (ANOVA) and Bonferroni tests (P<0.05). Results No statistically significant differences were found among groups (P<0.05). Fracture resistance of endodontically treated teeth restored with a traditional resin composite and with a bulk fill flowable composite (SDR) was similar in both maxillary and mandibular molars and showed no significant decrease in fracture resistance compared to intact specimens. Conclusions No significant difference was observed in the mechanical fracture resistance of endodontically treated molars restored with traditional resin composite restorations compared to bulk fill flowable composite restorations. PMID:27486505

Fracture resistance of endodontically treated teeth restored with a bulkfill flowable material and a resin composite.

PubMed

Isufi, Almira; Plotino, Gianluca; Grande, Nicola Maria; Ioppolo, Pietro; Testarelli, Luca; Bedini, Rossella; Al-Sudani, Dina; Gambarini, Gianluca

2016-01-01

To determine and compare the fracture resistance of endodontically treated teeth restored with a bulk fill flowable material (SDR) and a traditional resin composite. Thirty maxillary and 30 mandibular first molars were selected based on similar dimensions. After cleaning, shaping and filling of the root canals and adhesive procedures, specimens were assigned to 3 subgroups for each tooth type (n=10): Group A: control group, including intact teeth; Group B: access cavities were restored with a traditional resin composite (EsthetX; Dentsply-Italy, Rome, Italy); Group C: access cavities were restored with a bulk fill flowable composite (SDR; Dentsply-Italy), except 1.5 mm layer of the occlusal surface that was restored with the same resin composite as Group B. The specimens were subjected to compressive force in a material static-testing machine until fracture occurred, the maximum fracture load of the specimens was measured (N) and the type of fracture was recorded as favorable or unfavorable. Data were statistically analyzed with one-way analysis of variance (ANOVA) and Bonferroni tests (P<0.05). No statistically significant differences were found among groups (P<0.05). Fracture resistance of endodontically treated teeth restored with a traditional resin composite and with a bulk fill flowable composite (SDR) was similar in both maxillary and mandibular molars and showed no significant decrease in fracture resistance compared to intact specimens. No significant difference was observed in the mechanical fracture resistance of endodontically treated molars restored with traditional resin composite restorations compared to bulk fill flowable composite restorations.

Profiles of Volatile Compounds in Black Currant (Ribes nigrum) Cultivars with Special Focus on Influence of Growth Latitude and Weather Conditions.

PubMed

Marsol-Vall, Alexis; Kortesniemi, Maaria Katariina; Karhu, Saila; Kallio, Heikki; Yang, Baoru

2018-06-25

The volatile profile of three blackcurrant (Ribes nigrum L.) cultivars grown in Finland and their response to growth latitude and weather conditions were studied over an eight-year period by headspace solid-phase microextraction (HS-SPME) followed by gas chromatographic-mass spectrometric (GC-MS) analysis. Monoterpene hydrocarbons and oxygenated monoterpenes were the major classes of volatiles. The cultivar 'Melalahti' presented lower content of volatiles compared with 'Ola' and 'Mortti', the two latter showing a very similar composition. Higher contents of volatiles were found in berries cultivated at higher latitude (66° 34' N) than in those from the southern location (60° 23' N). Among the meteorological variables, radiation and temperature during the last month before harvest were negatively linked with the volatile content. Storage time had a negative impact on the amount of blackcurrant volatiles.

Petrographic and Vitrinite Reflectance Analyses of a Suite of High Volatile Bituminous Coal Samples from the United States and Venezuela

USGS Publications Warehouse

Hackley, Paul C.; Kolak, Jonathan J.

2008-01-01

This report presents vitrinite reflectance and detailed organic composition data for nine high volatile bituminous coal samples. These samples were selected to provide a single, internally consistent set of reflectance and composition analyses to facilitate the study of linkages among coal composition, bitumen generation during thermal maturation, and geochemical characteristics of generated hydrocarbons. Understanding these linkages is important for addressing several issues, including: the role of coal as a source rock within a petroleum system, the potential for conversion of coal resources to liquid hydrocarbon fuels, and the interactions between coal and carbon dioxide during enhanced coalbed methane recovery and(or) carbon dioxide sequestration in coal beds.

Revised Thickness of the Lunar Crust from GRAIL Data: Implications for Lunar Bulk Composition

NASA Technical Reports Server (NTRS)

Taylor, G. Jeffrey; Wieczorek, Mark A.; Neumann, Gregory A.; Nimmo, Francis; Kiefer, Walter S.; Melosh, H. Jay; Phillips, Roger J.; Solomon, Sean C.; Andrews-Hanna, Jeffrey C.; Asmar, Sami W.;

Theoretical study on the electronic and optical properties of bulk and surface (001) InxGa1-xAs

NASA Astrophysics Data System (ADS)

Liu, XueFei; Ding, Zhao; Luo, ZiJiang; Zhou, Xun; Wei, JieMin; Wang, Yi; Guo, Xiang; Lang, QiZhi

2018-05-01

The optical properties of surface and bulk InxGa1-xAs materials are compared systematically first time in this paper. The band structures, density of states and optical properties including dielectric function, reflectivity, absorption coefficient, loss function and refractive index of bulk and surface InxGa1-xAs materials are investigated by first-principles based on plane-wave pseudo-potentials method within the LDA approximation. The results agree well with the available theoretical and experimental studies and indicate that the electronic and optical properties of bulk and surface InxGa1-xAs materials are much different, and the results show that the considered optical properties of the both materials vary with increasing indium composition in an opposite way. The calculations show that the optical properties of surface In0.75Ga0.25As material are unexpected to be far from the other two indium compositions of surface InxGa1-xAs materials while the optical properties of bulk InxGa1-xAs materials vary with increasing indium composition in an expected regular way.

Effect of muscle type and vacuum chiller aging period on the chemical compositions, meat quality, sensory attributes and volatile compounds of Korean native cattle beef.

PubMed

Ba, Hoa Van; Park, KyoungMi; Dashmaa, Dashdorj; Hwang, Inho

2014-02-01

The present study demonstrates the effects of different muscle types and chiller ageing periods on the chemical composition, meat quality parameters, sensory characteristics and volatile compounds of Karean native cattle beed. Longissimus dorsi (LD) and Semitendinosus (ST) muscles aged for 7 days and 28 days were used. Moisture, cooking loss, total collagen and Warner-Bratzler shear force (WBSF) values for the ST were higher than the LD muscle regardless of ageing period (P < 0.05). The LD muscle had higher intramuscular fat (IMF) (P < 0.05). Ageing for 28 days decreased WBSF values whereas it increased thiobarbituric acid of both muscles. Moreover, tenderness, juiciness and flavor scores were significantly higher for the LD muscle at both ageing periods. Increased ageing time improved tenderness of both muscles, and increased juiciness of the LD muscle, whereas there was decreased flavor score of ST muscle (P < 0.05). The majority of the volatile compounds formed from the oxidation of lipids showed differences between the two muscles. Ageing for 28 days increased in the amounts of many volatile compounds; however, the amounts of some important volatile compounds were decreased. These results clearly demonstrate that muscle type and ageing have a potential effect on meat quality, sensory characteristics and volatile profile. © 2013 Japanese Society of Animal Science.

Volatile Concentrations and H-Isotope Composition of Unequilibrated Eucrites

NASA Technical Reports Server (NTRS)

Sarafian, Adam R.; Nielsen, Sune G.; Marschall, Horst R.; Gaetani, Glenn A.; Hauri, Erik H.; Righter, Kevin; Berger, Eve L.

2017-01-01

Eucrites are among the oldest and best studied asteroidal basalts (1). They represent magmatism that occurred on their parent asteroid, likely 4-Vesta, starting at 4563 Ma and continuing for approx. 30 Myr. Two hypotheses are debated for the genesis of eucrites, a magma ocean model (2), and a mantle partial melting model. In general, volatiles (H, C, F, Cl) have been ignored for eucrites and 4-Vesta, but solubility of wt% levels of H2O are possible at Vestan interior PT conditions. Targeted measurements on samples could aid our understanding considerably. Recent studies have found evidence of volatile elements in eucrites, but quantifying the abundance of volatiles remains problematic (6). Volatile elements have a disproportionately large effect on melt properties and phase stability, relative to their low abundance. The source of volatile elements can be elucidated by examining the hydrogen isotope ratio (D/H), as different H reservoirs have drastically different H isotope compositions. Recent studies of apatite in eucrites have shown that the D/H of 4-Vesta matches that of Earth and carbonaceous chondrites, however, the D/H of apatites may not represent the D/H of a primitive 4-Vesta melt due to the possibility of degassing prior to the crystallization of apatite. Therefore, the D/H of early crystallizing phases must be measured to determine if the D/H of 4-Vesta is equal to that of the Earth and carbonaceous chondrites.

Yellow Starthistle (Centaurea solstitialis) volatile composition under elevated temperature and CO2 in the field

USDA-ARS?s Scientific Manuscript database

Global climate change is already occurring and may affect biogenic volatile organic compounds (VOCs) involved in plant communication. Whether climate change will promote expansion of invasive species is still unclear. Centaurea solstitialis (yellow starthistle) is a major invasive weed in western No...

VALIDATION STUDIES OF THERMAL EXTRACTION-GC/MS APPLIED TO SOURCE EMISSIONS AEROSOLS: 1. SEMIVOLATILE ANALYTE--NONVOLATILE MATRIX INTERACTIONS

EPA Science Inventory

This work develops a novel validation approach for studying how non-volatile aerosol matrices of considerably different chemical composition potentially affect the thermal extraction (TE)/GC/MS quantification of a wide range of trace semivolatile organic markers. The non-volatil...

Method of making nanostructured glass-ceramic waste forms

DOEpatents

Gao, Huizhen; Wang, Yifeng; Rodriguez, Mark A.; Bencoe, Denise N.

2012-12-18

A method of rendering hazardous materials less dangerous comprising trapping the hazardous material in nanopores of a nanoporous composite material, reacting the trapped hazardous material to render it less volatile/soluble, sealing the trapped hazardous material, and vitrifying the nanoporous material containing the less volatile/soluble hazardous material.

SEPARATION OF VOLATILE ORGANIC COMPOUNDS FROM AQUEOUS SOLUTIONS BY PERVAPORATION USING S-B-S BLOCK COPOLYMER MEMBRANES.

EPA Science Inventory

Composite membranes of a block copolymer of styrene and butadiene (S-B-S) were cast on highly porous, hydrophobic thin films of PTFE, and used for the separation and recovery of volatile organic compounds (VOCs) from aqueous solutions by pervaporation. Trichloroethane, trichloroe...

Characterization of volatile and polar compounds of Jiaogulan Tea [Gynostemma pentaphyllum (Thunb.) Makino] by hyphenated analytical techniques

USDA-ARS?s Scientific Manuscript database

Jiaogulan [Gynostemma pentaphyllum (Thunb.) Makino] is a Chinese medical plant from southern Asia that has rapidly gained popularity and interest for its health-promotive and therapeutic properties. The volatile composition of jiaogulan tea was analyzed by using headspace-solid phase microextraction...

BIOGENIC VOLATILE ORGANIC COMPOUND EMISSIONS (BVOCS) I. IDENTIFICATIONS FROM THREE CONTINENTAL SITES IN THE U.S.

EPA Science Inventory

Vegetation composition and biomass were surveyed for three specific sites in Atlanta, GA; near Rhinelander, WI; and near Hayden, CO. At each research site, emissions of biogenic volatile organic compounds (BVOCs) from the dominant vegetation species were sampled by enclosing bran...

Volatile, anthocyanidin, quality and sensory changes in rabbiteye blueberry from whole fruit through pilot plant juice processing.

USDA-ARS?s Scientific Manuscript database

BACKGROUND: High antioxidant content and keen marketing have increased blueberry demand and increased local production which in turn mandates new uses for abundant harvests. Pilot scale processes were employed to investigate the anthocyanidin profiles, qualitative volatile compositions, and sensori...

SEPARATION OF VOLATILE ORGANIC COMPOUNDS FROM AQUEOUS SOLUTIONS BY PERVAPORATION USING S-B-S BLOCK COPOLYMER MEMBRANES

EPA Science Inventory

Composite membranes of a block copolymer of styrene and butadiene (S-B-S) were cast on highly porous, hydrophobic thin films of PTFE and used for the separation and recovery of volatile organic compounds (VOCs) from aqueous solutions by pervaporation. Trichloroethane, trichloroe...

Full in-vitro analyses of new-generation bulk fill dental composites cured by halogen light.

PubMed

Tekin, Tuçe Hazal; Kantürk Figen, Aysel; Yılmaz Atalı, Pınar; Coşkuner Filiz, Bilge; Pişkin, Mehmet Burçin

2017-08-01

The objective of this study was to investigate the full in-vitro analyses of new-generation bulk-fill dental composites cured by halogen light (HLG). Two types' four composites were studied: Surefill SDR (SDR) and Xtra Base (XB) as bulk-fill flowable materials; QuixFill (QF) and XtraFill (XF) as packable bulk-fill materials. Samples were prepared for each analysis and test by applying the same procedure, but with different diameters and thicknesses appropriate to the analysis and test requirements. Thermal properties were determined by thermogravimetric analysis (TG/DTG) and differential scanning calorimetry (DSC) analysis; the Vickers microhardness (VHN) was measured after 1, 7, 15 and 30days of storage in water. The degree of conversion values for the materials (DC, %) were immediately measured using near-infrared spectroscopy (FT-IR). The surface morphology of the composites was investigated by scanning electron microscopes (SEM) and atomic-force microscopy (AFM) analyses. The sorption and solubility measurements were also performed after 1, 7, 15 and 30days of storage in water. In addition to his, the data were statistically analyzed using one-way analysis of variance, and both the Newman Keuls and Tukey multiple comparison tests. The statistical significance level was established at p<0.05. According to the ISO 4049 standards, all the tested materials showed acceptable water sorption and solubility, and a halogen light source was an option to polymerize bulk-fill, resin-based dental composites. Copyright © 2017 Elsevier B.V. All rights reserved.

Hydrogen and carbon isotopic composition of volatiles in Nakhla: Implications for weathering on Mars

NASA Technical Reports Server (NTRS)

Watson, L. L.; Epstein, S.; Stolper, E. M.

1992-01-01

Gases were collected at 120, 200, 300, 415, and 600 and 850 C. Hydrogen yields for the 600 and 850 C aliquots were measured separately and then the gases were combined for isotopic analysis. CO2 samples collected at the two lowest temperature steps amounted to less than 0.5 mu mole and were not analyzed isotopically. Excluding the 120 C temperature step, the bulk delta D of the sample was + 187 percent. Delta D values increase from -91 percent in the 120 C step to +518 percent in the 315 to 850 C step. The hydrogen content is greatest in the 120 C step and is roughly constant in the 200, 300, and 415 C aliquots. Between 415 C and 850 C, the yield drops off considerably. From 850 C to 950 C, virtually no H2 and only minor CO2 (less than 1 mu mole) were extracted. Using the isotopic analysis from the 300, 415, 600, and 850 C temperature collections, the bulk delta C-13 sub (PDB) is 0.0 percent. The heaviest component (delta C-13 sub (PDB) of +29 percent) was collected between 300 and 415 C. The release of hydrogen at the low temperatures reported here is consistent with the breakdown of the phases that constitute the alteration product between approx. 250 and 650 C. Although not as high as the present Martian atmosphere, the high delta D values are consistent with a Martian origin for the meteorites in question.

Trends in restorative composites research: what is in the future?

PubMed

Maas, Mariel Soeiro; Alania, Yvette; Natale, Livia Camargo; Rodrigues, Marcela Charantola; Watts, David Christopher; Braga, Roberto Ruggiero

2017-08-28

Clinical trials have identified secondary caries and bulk fracture as the main causes for composite restoration failure. As a measure to avoid frequent reinterventions for restoration replacement, composites with some sort of defense mechanism against biofilm formation and demineralization, as well as materials with lower susceptibility to crack propagation are necessary. Also, the restorative procedure with composites are very time-consuming and technically demanding, particularly concerning the application of the adhesive system. Therefore, together with bulk-fill composites, self-adhesive restorative composites could reduce operator error and chairside time. This literature review describes the current stage of development of remineralizing, antibacterial and self-healing composites. Also, an overview of the research on fiber-reinforced composites and self-adhesive composites, both introduced for clinical use in recent years, is presented.

Do volcanic gases represent equilibrium volatile concentrations? Some insights from a model of diffusive fractionation during rapid bubble growth

NASA Astrophysics Data System (ADS)

Baker, D. R.

2012-12-01

Measurements of volcanic gas compositions are often presumed to be directly related to equilibrium compositions of fluids exsolved at depth in magmatic systems that rapidly escape into the atmosphere. In particular, changes in the ratios of volatile species concentrations in volcanic gases have been interpreted to reflect influx of new magma batches or changes in the degassing depth. However, other mechanisms can also yield changes in volcanic gas compositions. One such mechanism is diffusive fractionation during rapid bubble growth. Such fractionation can occur because radial growth rates of bubbles in magmas are estimated to be in the range of 10-6 to 10-3 m s-1 and diffusion coefficients of minor volatiles (e.g., Cl, F, S, CO2) are orders of magnitude slower, 10-12 to 10-9 m2 s-1. Thus a bubble that rapidly grows and subsequently loses its volatiles to the surface may contribute a fluid sample whose concentration is affected by the interplay between the kinetics of bubble growth and volatile diffusion in the melt. A finite difference code was developed to calculate the effects of rapid bubble growth on the concentration of minor elements in the bubble for a spherical growth geometry. The bubble is modeled with a fixed growth rate and a constant equilibrium fluid-melt partition coefficient, KD. Bubbles were modeled to grow to a radius of 50 μm, the size at which the dominant bubble growth mechanism appears to change from diffusion to coalescence. The critical variables that control the departure from equilibrium behavior are the K D and the ratio of the growth velocity, V, to the diffusivity, D. Modeling bubble growth in a magma chamber at 100 MPa demonstrates that when KD is in the range of 10 to 1000 at low V/D values (e.g., 103 m-1) the composition of the fluid is at, or near, equilibrium with the melt. However, as V/D increases the bubble composition deviates increasingly from equilibrium. For V/D ratios of 105 and equilibrium KD's of either 50 or 100 (similar to estimates for S), a bubble with a 50 μm radius will contain a fluid whose concentration was apparently determined by a KD of less than 10. These models also demonstrate that the combination of rapid bubble growth with slow diffusion can deplete the melt in the volatile species only within the immediate neighborhood, on the order of 100 μm. If bubbles are spaced further apart the melts may retain significant concentrations of dissolved volatiles, which could lead to secondary and tertiary nucleation events. These models for diffusive fractionation during rapid bubble growth suggest that changes in the ratios of minor elements in volcanic gases may be influenced by bubble growth rate changes. Volatiles with lower diffusivities and volatiles with very high or very low partition coefficients will be more influenced by this process. Diffusive fractionation may be responsible for the drop in the CO2/SO2 ratios sometimes observed prior to large eruptions of Stromboli volcano.

Composition and emission dynamics of migratory locust volatiles in response to changes in developmental stages and population density.

PubMed

Wei, Jianing; Shao, Wenbo; Wang, Xianhui; Ge, Jin; Chen, Xiangyong; Yu, Dan; Kang, Le

2017-02-01

Chemical communication plays an important role in density-dependent phase change in locusts. However, the volatile components and emission patterns of the migratory locust, Locusta migratoria, are largely unknown. In this study, we identified the chemical compositions and emission dynamics of locust volatiles from the body and feces and associated them with developmental stages, sexes and phase changes. The migratory locust shares a number of volatile components with the desert locust (Schistocerca gregaria), but the emission dynamics of the two locust species are significantly different. The body odors of the gregarious nymphs in the migratory locust consisted of phenylacetonitrile (PAN), benzaldehyde, guaiacol, phenol, aliphatic acids and 2,3-butanediol, and PAN was the dominant volatile. Volatiles from the fecal pellets of the nymphs primarily consist of guaiacol and phenol. Principal component analysis (PCA) showed significant differences in the volatile profiles between gregarious and solitary locusts. PAN and 4-vinylanisole concentrations were significantly higher in gregarious individuals than in solitary locusts. Gregarious mature males released significantly higher amounts of PAN and 4-vinylanisole during adulthood than mature females and immature adults of both sexes. Furthermore, PAN and 4-vinylanisole were completely lost in gregarious nymphs during the solitarization process, but were obtained by solitary nymphs during gregarization. The amounts of benzaldehyde, guaiacol and phenol only unidirectionally decreased from solitary to crowded treatment. Aliphatic aldehydes (C7 to C10), which were previously reported as locust volatiles, are now identified as environmental contaminants. Therefore, our results illustrate the precise odor profiles of migratory locusts during developmental stages, sexes and phase change. However, the function and role of PAN and other aromatic compounds during phase transition need further investigation. © 2016 Institute of Zoology, Chinese Academy of Sciences.

Induction of stress volatiles and changes in essential oil content and composition upon microwave exposure in the aromatic plant Ocimum basilicum.

PubMed

Lung, Ildikó; Soran, Maria-Loredana; Opriş, Ocsana; Truşcă, Mihail Radu Cătălin; Niinemets, Ülo; Copolovici, Lucian

2016-11-01

Exposure to sustained low intensity microwaves can constitute a stress for the plants, but its effects on plant secondary chemistry are poorly known. We studied the influence of GSM and WLAN-frequency microwaves on emissions of volatile organic compounds and content of essential oil in the aromatic plant Ocimum basilicum L. hypothesizing that microwave exposure leads to enhanced emissions of stress volatiles and overall greater investment in secondary compounds. Compared to the control plants, microwave irradiation led to decreased emissions of β-pinene, α-phellandrene, bornyl acetate, β-myrcene, α-caryophyllene and benzaldehyde, but increased emissions of eucalyptol, estragole, caryophyllene oxide, and α-bergamotene. The highest increase in emission, 21 times greater compared to control, was observed for caryophyllene oxide. The irradiation resulted in increases in the essential oil content, except for the content of phytol which decreased by 41% in the case of GSM-frequency, and 82% in the case of WLAN-frequency microwave irradiation. The strongest increase in response to WLAN irradiation, >17 times greater, was observed for hexadecane and octane contents. Comparisons of volatile compositions by multivariate analyses demonstrated a clear separation of different irradiance treatments, and according to the changes in the volatile emissions, the WLAN-frequency irradiation represented a more severe stress than the GSM-frequency irradiation. Overall, these results demonstrating important modifications in the emission rates, essential oil content and composition indicate that microwave irradiation influences the quality of herbage of this economically important spice plant. Copyright © 2016 Elsevier B.V. All rights reserved.

Remote laser evaporative molecular absorption spectroscopy

NASA Astrophysics Data System (ADS)

Hughes, Gary B.; Lubin, Philip; Cohen, Alexander; Madajian, Jonathan; Kulkarni, Neeraj; Zhang, Qicheng; Griswold, Janelle; Brashears, Travis

2016-09-01

We describe a novel method for probing bulk molecular and atomic composition of solid targets from a distant vantage. A laser is used to melt and vaporize a spot on the target. With sufficient flux, the spot temperature rises rapidly, and evaporation of surface materials occurs. The melted spot creates a high-temperature blackbody source, and ejected material creates a plume of surface materials in front of the spot. Molecular and atomic absorption occurs as the blackbody radiation passes through the ejected plume. Bulk molecular and atomic composition of the surface material is investigated by using a spectrometer to view the heated spot through the ejected plume. The proposed method is distinct from current stand-off approaches to composition analysis, such as Laser-Induced Breakdown Spectroscopy (LIBS), which atomizes and ionizes target material and observes emission spectra to determine bulk atomic composition. Initial simulations of absorption profiles with laser heating show great promise for Remote Laser-Evaporative Molecular Absorption (R-LEMA) spectroscopy. The method is well-suited for exploration of cold solar system targets—asteroids, comets, planets, moons—such as from a spacecraft orbiting the target. Spatial composition maps could be created by scanning the surface. Applying the beam to a single spot continuously produces a borehole or trench, and shallow subsurface composition profiling is possible. This paper describes system concepts for implementing the proposed method to probe the bulk molecular composition of an asteroid from an orbiting spacecraft, including laser array, photovoltaic power, heating and ablation, plume characteristics, absorption, spectrometry and data management.

The mineralogy, petrology, and composition of anomalous eucrite Emmaville

NASA Astrophysics Data System (ADS)

Barrett, T. J.; Mittlefehldt, D. W.; Greenwood, R. C.; Charlier, B. L. A.; Hammond, S. J.; Ross, D. K.; Anand, M.; Franchi, I. A.; Abernethy, F. A. J.; Grady, M. M.

2017-04-01

The Emmaville eucrite is a relatively poorly studied basaltic achondrite with an anomalous oxygen isotope signature. In this study, we report comprehensive mineralogical, petrographic, and geochemical data from Emmaville in order to understand its petrogenesis and relationship with the basaltic eucrites. Emmaville is an unusually fine-grained, hornfelsic-textured metabasalt with pervasive impact melt veins and mineral compositions similar to those of typical basaltic eucrites. The major and trace element bulk composition of Emmaville is also typical of a basaltic eucrite. Three separated individual lithologies were also analyzed for O isotopes; a dark gray fraction (E1), a shocked lithology (E2), and a lighter gray portion (E3). Fractions E1 and E2 shared similar O isotope compositions to the bulk sample (E-B), whereas the lighter gray portion (E3) is slightly elevated in Δ17O and significantly elevated in δ18O compared to bulk. No evidence for any exogenous material is observed in the thin sections, coupled with the striking compositional similarity to typical basaltic eucrites, appears to preclude a simple impact-mixing hypothesis. The O-isotopes of Emmaville are similar to those of Bunburra Rockhole, A-881394, and EET 92023, and thus distinct from the majority of the HEDs, despite having similarities in petrology, mineral, and bulk compositions. It would, therefore, seem plausible that all four of these samples are derived from a single HED-like parent body that is isotopically distinct from that of the HEDs (Vesta) but similar in composition.

H2O-CO2-S-Cl partitioning and mixing in rhyolitic melts and fluid - Implications on closed-system degassing in rhyolite

NASA Astrophysics Data System (ADS)

Ding, S.; Webster, J. D.

2017-12-01

Magmatic degassing involving multiple volatile components (C, O, H, S, Cl, etc.) is one of the key factors influencing the timing and nature of volcanic eruptions, and the chemistry of volcanic gases released to the surface. In particular, exsolution of these volatiles from silicic magma during ascent could trigger explosive volcanic eruptions, which can exert strong impacts on surface temperature, ecology and human health. However, quantitative evaluation of this process in silicic magma remains ambiguous due to the lack of experiments in such chemically complex systems. Rhyolite-fluid(s) equilibria experiments were conducted in an IHPVat 100-300 MPa and 800 ° C to determine the solubilities, fluid-melt partitioning, and mixing properties of H2O, CO2, S, and Cl in the oxygen fugacity (fO2) range of FMQ to FMQ+3. The integrated bulk fluids contain up to 94 mol% H2O, 32 mol% CO2, 1 mol% S and 1mol% Cl. Rhyolite melt dissolved 20- 770 ppm CO2 and 4-7 wt.% H2O, varying with pressure, fluid composition, and fO2. Concentrations of H2O and CO2 in melt from C-O-H-S-Cl- bearing experiments at 100 and 200 MPa, and from C-O-H only experiments are generally consistent with the predictions of existing CO2-H2O solubility models based on the C-O-H only system [1-4], while the solubilities of H2O and CO2 in melt with addition of S±Cl at 300 MPa are less than those of the C-O-H- only system. This reduction in H2O and CO2 solubilities exceeds the effects of simple dilution of the coexisting fluid owing to addition of other volatiles, and rather, reflects complex mixing relations. Rhyolite melt also dissolved 20-150 ppm S and 850-2000 ppm Cl, varying with pressure. At 300 MPa, S concentrations in the melt change with fO2. The partitioning of CO2 and S between fluid and melt varies as a function of fluid composition and fO2. Solubilities and complex mixing relationships of CO2, H2O, S and Cl revealed in our experiments can be applied to massive rhyolitic eruptions like those of the Bishop tuff, Toba tuff and Pinatubo to better understand the degassing process, to estimate fluid compositions, and thus, to evaluate the potential environmental impacts of these super eruptions. [1] Ghiorso amd Gualda, 2015, CMP; [2] Liu et al., 2005, J. Volcanol. Geotherm. Res.; [3] Newman and Lowenstern, 2002, Comput. Geosci.; [3] Tamic et al., 2001, Chem. Geol..

The Odour of Sex: Sex-Related Differences in Volatile Compound Composition among Barn Swallow Eggs Carrying Embryos of Either Sex

PubMed Central

Costanzo, Alessandra; Panseri, Sara; Giorgi, Annamaria; Romano, Andrea; Caprioli, Manuela; Saino, Nicola

2016-01-01

Avian communication has been traditionally believed to be mainly mediated by visual and auditory channels. However, an increasing number of studies are disclosing the role of olfaction in the interaction of birds with their social environment and with other species, as well as in other behaviors such as nest recognition, food location and navigation. Olfaction has also been suggested to play a role in parent-offspring communication not only in the post- but also in the pre-hatching period. Volatile compounds produced during embryogenesis and passively released through the eggshell pores may indeed represent the only cue at parents’ disposal to assess offspring quality, including the sex composition of their clutch before hatching. In turn, sex identification before hatching may mediate adaptive strategies of allocation to either sex. In the present study, we analyzed odour composition of barn swallow eggs incubated in their nest in order to identify any sex-related differences in volatile compounds emitted. For the first time in any bird species, we also investigated whether odour composition is associated with relatedness. The evidence of differences in odour composition among eggs containing embryos of either sex indicates that parents have a cue to identify their brood sex composition even before hatching which can be used to modulate their behavior accordingly. Moreover, odour similarity within nests may represent the prerequisite for kin recognition in this species. PMID:27851741

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mallow, Anne M; Abdelaziz, Omar; Graham, Samuel

The thermal charging performance of phase change materials, specifically paraffin wax, combined with compressed expanded natural graphite foam is studied under constant heat flux and constant temperature conditions. By varying the heat flux between 0.39 W/cm2 and 1.55 W/cm2 or maintaining a boundary temperature of 60 C for four graphite foam bulk densities, the impact on the rate of thermal energy storage is discussed. Thermal charging experiments indicate that thermal conductivity of the composite is an insufficient metric to compare the influence of graphite foam on the rate of thermal energy storage of the PCM composite. By dividing the latentmore » heat of the composite by the time to melt for various boundary conditions and graphite foam bulk densities, it is determined that bulk density selection is dependent on the applied boundary condition. A greater bulk density is advantageous for samples exposed to a constant temperature near the melting temperature as compared to constant heat flux conditions where a lower bulk density is adequate. Furthermore, the anisotropic nature of graphite foam bulk densities greater than 50 kg/m3 is shown to have an insignificant impact on the rate of thermal charging. These experimental results are used to validate a computational model for future use in the design of thermal batteries for waste heat recovery.« less

Amorphous Metals and Composites as Mirrors and Mirror Assemblies

NASA Technical Reports Server (NTRS)

Hofmann, Douglas C. (Inventor); Davis, Gregory L. (Inventor); Agnes, Gregory S. (Inventor); Shapiro, Andrew A. (Inventor)

2016-01-01

A mirror or mirror assembly fabricated by molding, pressing, assembling, or depositing one or more bulk metal glass (BMG), bulk metal glass composite (BMGMC), or amorphous metal (AM) parts and where the optical surface and backing of the mirror can be fabricated without machining or polishing by utilizing the unique molding capabilities of this class of materials.

Selective Detection of Target Volatile Organic Compounds in Contaminated Humid Air Using a Sensor Array with Principal Component Analysis

PubMed Central

Itoh, Toshio; Akamatsu, Takafumi; Tsuruta, Akihiro; Shin, Woosuck

2017-01-01

We investigated selective detection of the target volatile organic compounds (VOCs) nonanal, n-decane, and acetoin for lung cancer-related VOCs, and acetone and methyl i-butyl ketone for diabetes-related VOCs, in humid air with simulated VOC contamination (total concentration: 300 μg/m3). We used six “grain boundary-response type” sensors, including four commercially available sensors (TGS 2600, 2610, 2610, and 2620) and two Pt, Pd, and Au-loaded SnO2 sensors (Pt, Pd, Au/SnO2), and two “bulk-response type” sensors, including Zr-doped CeO2 (CeZr10), i.e., eight sensors in total. We then analyzed their sensor signals using principal component analysis (PCA). Although the six “grain boundary-response type” sensors were found to be insufficient for selective detection of the target gases in humid air, the addition of two “bulk-response type” sensors improved the selectivity, even with simulated VOC contamination. To further improve the discrimination, we selected appropriate sensors from the eight sensors based on the PCA results. The selectivity to each target gas was maintained and was not affected by contamination. PMID:28753948

Spreading of a liquid film on a substrate by the evaporation-adsorption process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wayner, P.C. Jr.; Schonberg, J.

1992-09-01

The importance of evaporation followed by multilayer adsorption in comparison to liquid flow at the leading edge of a volatile spreading film is analyzed. Presuming that both flows are functions of the same chemical potential gradient, a dimensionless group (N) which delineates the relative importance of vapor diffusion flow to viscous flow on the surface is obtained: N = [rho][sub i]D[nu]x/([minus][bar A][pi]). The relative importance of vapor flow increases with the vapor-pressure dependent partial density, [rho][sub i], and diffusivity, D, of the diffusing vapor, the kinematic viscosity of the liquid, [nu], and the distance downstream from the bulk liquid region,more » x, and decreases with the Hamaker constant, 6[pi][bar A]. Using physical properties the modifiers volatile'' and nonvolatile'' can thereby be put in perspective. Changes in the interfacial force field are a function of [bar A]. The spreading velocity due to the vapor diffusion process is obtained and is found to decrease with a decrease in the interfacial force field and the bulk vapor pressure. The infinite stress at the contact line can be easily relieved by evaporation-adsorption in many systems.« less

Effect of atmospheric ageing on volatility and ROS of biodiesel exhaust nano-particles

NASA Astrophysics Data System (ADS)

Pourkhesalian, A. M.; Stevanovic, S.; Rahman, M. M.; Faghihi, E. M.; Bottle, S. E.; Masri, A. R.; Brown, R. J.; Ristovski, Z. D.

2015-03-01

In the prospect of limited energy resources and climate change, effects of alternative biofuels on primary emissions are being extensively studied. Our two recent studies have shown that biodiesel fuel composition has a~significant impact on primary particulate matter emissions. It was also shown that particulate matter caused by biodiesels was substantially different from the emissions due to petroleum diesel. Emissions appeared to have higher oxidative potential with the increase in oxygen content and decrease of carbon chain length and unsaturation levels of fuel molecules. Overall, both studies concluded that chemical composition of biodiesel is more important than its physical properties in controlling exhaust particle emissions. This suggests that the atmospheric ageing processes, including secondary organic aerosol formation, of emissions from different fuels will be different as well. In this study, measurements were conducted on a modern common-rail diesel engine. To get more information on realistic properties of tested biodiesel particulate matter once they are released into the atmosphere, particulate matter was exposed to atmospheric oxidants, ozone and ultra-violet light; and the change in their properties was monitored for different biodiesel blends. Upon the exposure to oxidative agents, the chemical composition of the exhaust changes. It triggers the cascade of photochemical reactions resulting in the partitioning of semi-volatile compounds between the gas and particulate phase. In most of the cases, aging lead to the increase in volatility and oxidative potential, and the increment of change was mainly dependent on the chemical composition of fuels as the leading cause for the amount and the type of semi-volatile compounds present in the exhaust.

Nacre-mimetic bulk lamellar composites reinforced with high aspect ratio glass flakes.

PubMed

Guner, Selen N Gurbuz; Dericioglu, Arcan F

2016-12-05

Nacre-mimetic epoxy matrix composites reinforced with readily available micron-sized high aspect ratio C-glass flakes were fabricated by a relatively simple, single-step, scalable, time, cost and man-power effective processing strategy: hot-press assisted slip casting (HASC). HASC enables the fabrication of preferentially oriented two-dimensional inorganic reinforcement-polymer matrix bulk lamellar composites with a micro-scale structure resembling the brick-and-mortar architecture of nacre. By applying the micro-scale design guideline found in nacre and optimizing the relative volume fractions of the reinforcement and the matrix as well as by anchoring the brick-and-mortar architecture, and tailoring the interface between reinforcements and the matrix via silane coupling agents, strong, stiff and tough bio-inspired nacre-mimetic bulk composites were fabricated. As a result of high shear stress transfer lengths and effective stress transfer at the interface achieved through surface functionalization of the reinforcements, fabricated bulk composites exhibited enhanced mechanical performance as compared to neat epoxy. Furthermore, governed flake pull-out mode along with a highly torturous crack path, which resulted from extensive deflection and meandering of the advancing crack around well-aligned high aspect ratio C-glass flakes, have led to high work-of-fracture values similar to nacre.

Genetic analysis of the wild strawberry (Fragaria vesca) volatile composition.

PubMed

Urrutia, María; Rambla, José L; Alexiou, Konstantinos G; Granell, Antonio; Monfort, Amparo

2017-12-01

The volatile composition of wild strawberry (Fragaria vesca) fruit differs from that of the cultivated strawberry, having more intense and fruity aromas. Over the last few years, the diploid F. vesca has been recognized as a model species for genetic studies of cultivated strawberry (F. x ananassa), and here a previously developed F. vesca/F. bucharica Near Isogenic Line collection (NIL) was used to explore genetic variability of fruit quality traits. Analysis of fruit volatiles by GC-MS in our NIL collection revealed a complex and highly variable profile. One hundred compounds were unequivocally identified, including esters, aldehydes, ketones, alcohols, terpenoids, furans and lactones. Those in a subset, named key volatile compounds (KVCs), are likely contributors to the special aroma/flavour of wild strawberry. Genetic analysis revealed 50 major quantitative trait loci (QTL) including 14 QTL for KVCs, and one segregating as a dominant monogenetic trait for nerolidol. The most determinant regions affecting QTLs for KVCs, were mapped on LG5 and LG7. New candidate genes for the volatile QTL are proposed, based on differences in gene expression between NILs containing specific fragments of F. bucharica and the F. vesca recurrent genome. A high percentage of these candidate genes/alleles were colocalized within the boundaries of introgressed regions that contain QTLs, appearing to affect volatile metabolite accumulation acting in cis. A NIL collection is a good tool for the genetic dissection of volatile accumulation in wild strawberry fruit and a source of information for genes and alleles which may enhance aroma in cultivated strawberry. Copyright © 2017 The Authors. Published by Elsevier Masson SAS.. All rights reserved.

Phytochemical Profiles and Antimicrobial Activities of Allium cepa Red cv. and A. sativum Subjected to Different Drying Methods: A Comparative MS-Based Metabolomics.

PubMed

Farag, Mohamed A; Ali, Sara E; Hodaya, Rashad H; El-Seedi, Hesham R; Sultani, Haider N; Laub, Annegret; Eissa, Tarek F; Abou-Zaid, Fouad O F; Wessjohann, Ludger A

2017-05-08

Plants of the Allium genus produce sulphur compounds that give them a characteristic (alliaceous) flavour and mediate for their medicinal use. In this study, the chemical composition and antimicrobial properties of Allium cepa red cv. and A. sativum in the context of three different drying processes were assessed using metabolomics. Bulbs were dried using either microwave, air drying, or freeze drying and further subjected to chemical analysis of their composition of volatile and non-volatile metabolites. Volatiles were collected using solid phase micro-extraction (SPME) coupled to gas chromatography-mass spectrometry (GC/MS) with 42 identified volatiles including 30 sulphur compounds, four nitriles, three aromatics, and three esters. Profiling of the polar non-volatile metabolites via ultra-performance liquid chromatography coupled to high resolution MS (UPLC/MS) annotated 51 metabolites including dipeptides, flavonoids, phenolic acids, and fatty acids. Major peaks in GC/MS or UPLC/MS contributing to the discrimination between A. sativum and A. cepa red cv. were assigned to sulphur compounds and flavonoids. Whereas sulphur conjugates amounted to the major forms in A. sativum , flavonoids predominated in the chemical composition of A. cepa red cv. With regard to drying impact on Allium metabolites, notable and clear separations among specimens were revealed using principal component analysis (PCA). The PCA scores plot of the UPLC/MS dataset showed closer metabolite composition of microwave dried specimens to freeze dried ones, and distant from air dried bulbs, observed in both A. cepa and A. sativum . Compared to GC/MS, the UPLC/MS derived PCA model was more consistent and better in assessing the impact of drying on Allium metabolism. A phthalate derivative was found exclusively in a commercial garlic preparation via GC/MS, of yet unknown origin. The freeze dried samples of both Allium species exhibited stronger antimicrobial activities compared to dried specimens with A. sativum being in general more active than A. cepa red cv.

Apatite-Melt Partitioning at 1 Bar: An Assessment of Apatite-Melt Exchange Equilibria Resulting from Non-Ideal Mixing of F and Cl in Apatite

NASA Technical Reports Server (NTRS)

McCubbin, F. M.; Ustunisik, G.; Vander Kaaden, K. E.

2016-01-01

The mineral apatite [Ca5(PO4)3(F,Cl,OH)] is present in a wide range of planetary materials. Due to the presence of volatiles within its crystal structure (X-site), many recent studies have attempted to use apatite to constrain the volatile contents of planetary magmas and mantle sources. In order to use the volatile contents of apatite to precisely determine the abundances of volatiles in coexisting silicate melt or fluids, thermodynamic models for the apatite solid solution and for the apatite components in multi-component silicate melts and fluids are required. Although some thermodynamic models for apatite have been developed, they are incomplete. Furthermore, no mixing model is available for all of the apatite components in silicate melts or fluids, especially for F and Cl components. Several experimental studies have investigated the apatite-melt and apatite-fluid partitioning behavior of F, Cl, and OH in terrestrial and planetary systems, which have determined that apatite-melt partitioning of volatiles are best described as exchange equilibria similar to Fe-Mg partitioning between olivine and silicate melt. However, McCubbin et al. recently reported that the exchange coefficients may vary in portions of apatite compositional space where F, Cl, and OH do not mix ideally in apatite. In particular, solution calorimetry data of apatite compositions along the F-Cl join exhibit substantial excess enthalpies of mixing. In the present study, we conducted apatite-melt partitioning experiments in evacuated, sealed silica-glass tubes at approximately 1 bar and 950-1050 degrees Centigrade on a synthetic Martian basalt composition equivalent to the basaltic shergottite Queen Alexandria Range (QUE) 94201. These experiments were conducted dry, at low pressure, to assess the effects of temperature and apatite composition on the partitioning behavior of F and Cl between apatite and basaltic melt along the F-Cl apatite binary join, where there is non-ideal mixing of F and Cl in apatite.

Chemical Composition Analysis of Extracts from Ficus Hirta Using Supercritical Fluid

NASA Astrophysics Data System (ADS)

Deng, S. B.; Chen, J. P.; Chen, Y. Z.; Yu, C. Q.; Yang, Y.; Wu, S. H.; Chen, C. Z.

2018-05-01

Ficus hirta was extracted by supercritical carbon dioxide. The volatile chemical components of extracts were analyzed using gas chromatography-mass spectrometry (GC-MS). The percentage of products extracted by Supercritical Fluid Extraction(SFE) was 2.5%. Nineteen volatile compounds were identified. The main volatile components were Elemicin, Psoralen, Palmitic acid, Bergapten, α-Linolenic acid, Medicarpin, Retinoic Acid, Maackiain, and Squalene. The method is simple and quick, and can be used for the preliminary analysis of chemical constituents of supercritical extracts of Ficus hirta.

Payload Design for the Lunar Flashlight Mission

NASA Technical Reports Server (NTRS)

Cohen, B. A.; Hayne, P. O.; Greenhagen, B. T.; Paige, D. A.; Camacho, J. M.; Crabtree, K.; Paine, C.; Sellar, G.

2017-01-01

Recent reflectance data from LRO (Lunar Reconnaissance Orbiter) instruments suggest water ice and other volatiles may be present on the surface in lunar permanently shadowed regions, though the detection is not yet definitive. Understanding the composition, quantity, distribution, and form of water and other volatiles associated with lunar permanently shadowed regions (PSRs) is identified as a NASA Strategic Knowledge Gap (SKG). These polar volatile deposits are also scientifically interesting, having the potential to reveal important information about the delivery of water to the Earth-Moon system.

Lunar Flashlight: Illuminating the Lunar South Pole

NASA Technical Reports Server (NTRS)

Hayne, P. O.; Greenhagen,, B. T.; Paige, D. A.; Camacho, J. M.; Cohen, B. A.; Sellar, G.; Reiter, J.

2016-01-01

Recent reflectance data from LRO instruments suggest water ice and other volatiles may be present on the surface in lunar permanentlyshadowed regions, though the detection is not yet definitive. Understanding the composition, quantity, distribution, and form of water and other volatiles associated with lunar permanently shadowed regions (PSRs) is identified as a NASA Strategic Knowledge Gap (SKG) for Human Exploration. These polar volatile deposits are also scientifically interesting, having the potential to reveal important information about the delivery of water to the Earth- Moon system.

Lunar Flashlight: Illuminating the Moon's South Pole

NASA Technical Reports Server (NTRS)

Hayne, P. O.; Cohen, B. A.; Greenhagen, B. T.; Paige, D. A.; Camacho, J. M.; Sellar, R. G.; Reiter, J.

2016-01-01

Recent reflectance data from LRO instruments suggest water ice and other volatiles may be present on the surface in lunar permanently shadowed regions, though the detection is not yet definitive. Understanding the composition, quantity, distribution, and form of water and other volatiles associated with lunar permanently shadowed regions (PSRs) is identified as a NASA Strategic Knowledge Gap (SKG) for Human Exploration. These polar volatile deposits are also scientifically interesting, having the potential to reveal important information about the delivery of water to the Earth-Moon system.

Sintering Process and Mechanical Property of MWCNTs/HDPE Bulk Composite

PubMed Central

Tze-Chi, Hsu; Jie-Ren, Zheng

2009-01-01

Studies have proved that increasing polymer matrices by carbon nanotubes to form structural reinforcement and electrical conductivity have significantly improved mechanical and electrical properties at very low carbon nanotubes loading. In other words, increasing polymer matrices by carbon nanotubes to form structural reinforcement can reduce friction coefficient and enhance anti-wear property. However, producing traditional MWCNTs in polymeric materix is an extremely complicated process. Using melt-mixing process or in situ polymerization leads to better dispersion effect on composite materials. In this study, therefore, to simplify MWCNTs /HDPE composite process and increase dispersion, powder was used directly to replace pellet to mix and sinter with MWCNTs. The composite bulks with 0, 0.5, 1, 2 and 4% nanotube content by weight was analyzed under SEM to observe nanotubes dispersion. At this rate, a MWCNTs/HDPE composite bulk with uniformly dispersed MWCNTs was achieved, and through the wear bench (Pin-on-Disk), the wear experiment has accomplished. Accordingly, the result suggests the sintered MWCNTs/HDPE composites amplify the hardness and wear-resist property. PMID:19730688

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cook, Ryan D.; Lin, Ying-Hsuan; Peng, Zhuoyu

Organic aerosol formation and transformation occurs within aqueous aerosol and cloud droplets, yet little is known about the composition of high molecular weight organic compounds in cloud water. Cloud water samples collected at Whiteface Mountain, New York, during August-September 2014 were analyzed by ultra-high-resolution mass spectrometry to investigate the molecular composition of dissolved organic carbon, with a focus on sulfur- and nitrogen-containing compounds. Organic molecular composition was evaluated in the context of cloud water inorganic ion concentrations, pH, and total organic carbon concentrations to gain insights into the sources and aqueous-phase processes of the observed high molecular weight organic compounds.more » Cloud water acidity was positively correlated with the average oxygen : carbon ratio of the organic constituents, suggesting the possibility for aqueous acid-catalyzed (prior to cloud droplet activation or during/after cloud droplet evaporation) and/or radical (within cloud droplets) oxidation processes. Many tracer compounds recently identified in laboratory studies of bulk aqueous-phase reactions were identified in the cloud water. Organosulfate compounds, with both biogenic and anthropogenic volatile organic compound precursors, were detected for cloud water samples influenced by air masses that had traveled over forested and populated areas. Oxidation products of long-chain (C 10-12) alkane precursors were detected during urban influence. Influence of Canadian wildfires resulted in increased numbers of identified sulfur-containing compounds and oligomeric species, including those formed through aqueous-phase reactions involving methylglyoxal. Light-absorbing aqueous-phase products of syringol and guaiacol oxidation were observed in the wildfire-influenced samples, and dinitroaromatic compounds were observed in all cloud water samples (wildfire, biogenic, and urban-influenced). Overall, the cloud water molecular composition depended on air mass source influence and reflected aqueous-phase reactions involving biogenic, urban, and biomass burning precursors.« less

Ammonia volatilization and atmospheric N deposition following straw and urea application from a rice-wheat rotation in southeastern China

NASA Astrophysics Data System (ADS)

Sun, Liying; Wu, Zhen; Ma, Yuchun; Liu, Yinglie; Xiong, Zhengqin

2018-05-01

Ammonia is a vital component of the nitrogen (N) cycle of terrestrial ecosystems in terms of volatilization and deposition. Here, a field experiment was undertaken to simultaneously investigate the effects of rice straw and urea incorporation on ammonia volatilization, atmospheric N deposition, yields and agronomic nitrogen use efficiency (NUE) under a rice-wheat system in China. The experiment involved four treatments: control (0 N, 0 straw), NS0 (250 kg N ha-1 season-1, 0 straw), NS1 (250 kg N ha-1 season-1, 3 t ha-1 yr-1 straw), and NS2 (250 kg N ha-1 season-1, 6 t ha-1 yr-1 straw) in the rice-wheat annual rotation system. The results indicated that the NS0, NS1 and NS2 treatments emitted cumulative ammonia of 14.0%, 16.4%, and 19.2%, respectively in the rice season and 7.6%, 11.1%, and 12.3%, respectively in the wheat season among the total urea-N application. Compared to the NS0 treatment, the NS1 and NS2 treatments significantly increased the cumulative ammonia emissions by 15.5% (p < 0.05) and 33.5% (p < 0.05), respectively in the rice season and 39.9% (p < 0.05) and 53.1% (p < 0.05), respectively in the wheat season. There was no significant difference between the NS2 and NS1 treatments during the wheat season. The amount of NH4+-N deposition accounted for 56.1% of the total inorganic N deposition during the whole rice-wheat system. The bulk NH4+-N deposition during the period of fertilization contributed 73.9% and 5.7% to the total NH4+-N deposition in the rice and wheat season, respectively. Overall, straw incorporation increased ammonia volatilization, not affecting the crop grain yield or NUE. The seasonal variation in NH4+-N bulk deposition was closely related to N fertilizer application.

Halogens in chondritic meteorites and terrestrial accretion

NASA Astrophysics Data System (ADS)

Clay, Patricia L.; Burgess, Ray; Busemann, Henner; Ruzié-Hamilton, Lorraine; Joachim, Bastian; Day, James M. D.; Ballentine, Christopher J.

2017-11-01

Volatile element delivery and retention played a fundamental part in Earth’s formation and subsequent chemical differentiation. The heavy halogens—chlorine (Cl), bromine (Br) and iodine (I)—are key tracers of accretionary processes owing to their high volatility and incompatibility, but have low abundances in most geological and planetary materials. However, noble gas proxy isotopes produced during neutron irradiation provide a high-sensitivity tool for the determination of heavy halogen abundances. Using such isotopes, here we show that Cl, Br and I abundances in carbonaceous, enstatite, Rumuruti and primitive ordinary chondrites are about 6 times, 9 times and 15-37 times lower, respectively, than previously reported and usually accepted estimates. This is independent of the oxidation state or petrological type of the chondrites. The ratios Br/Cl and I/Cl in all studied chondrites show a limited range, indistinguishable from bulk silicate Earth estimates. Our results demonstrate that the halogen depletion of bulk silicate Earth relative to primitive meteorites is consistent with the depletion of lithophile elements of similar volatility. These results for carbonaceous chondrites reveal that late accretion, constrained to a maximum of 0.5 ± 0.2 per cent of Earth’s silicate mass, cannot solely account for present-day terrestrial halogen inventories. It is estimated that 80-90 per cent of heavy halogens are concentrated in Earth’s surface reservoirs and have not undergone the extreme early loss observed in atmosphere-forming elements. Therefore, in addition to late-stage terrestrial accretion of halogens and mantle degassing, which has removed less than half of Earth’s dissolved mantle gases, the efficient extraction of halogen-rich fluids from the solid Earth during the earliest stages of terrestrial differentiation is also required to explain the presence of these heavy halogens at the surface. The hydropilic nature of halogens, whereby they track with water, supports this requirement, and is consistent with volatile-rich or water-rich late-stage terrestrial accretion.

Silicic volcanism on Mars evidenced by tridymite in high-SiO2 sedimentary rock at Gale crater

NASA Astrophysics Data System (ADS)

Morris, Richard V.; Vaniman, David T.; Blake, David F.; Gellert, Ralf; Chipera, Steve J.; Rampe, Elizabeth B.; Ming, Douglas W.; Morrison, Shaunna M.; Downs, Robert T.; Treiman, Allan H.; Yen, Albert S.; Grotzinger, John P.; Achilles, Cherie N.; Bristow, Thomas F.; Crisp, Joy A.; Des Marais, David J.; Farmer, Jack D.; Fendrich, Kim V.; Frydenvang, Jens; Graff, Trevor G.; Morookian, John-Michael; Stolper, Edward M.; Schwenzer, Susanne P.

2016-06-01

Tridymite, a low-pressure, high-temperature (>870 °C) SiO2 polymorph, was detected in a drill sample of laminated mudstone (Buckskin) at Marias Pass in Gale crater, Mars, by the Chemistry and Mineralogy X-ray diffraction instrument onboard the Mars Science Laboratory rover Curiosity. The tridymitic mudstone has ˜40 wt.% crystalline and ˜60 wt.% X-ray amorphous material and a bulk composition with ˜74 wt.% SiO2 (Alpha Particle X-Ray Spectrometer analysis). Plagioclase (˜17 wt.% of bulk sample), tridymite (˜14 wt.%), sanidine (˜3 wt.%), cation-deficient magnetite (˜3 wt.%), cristobalite (˜2 wt.%), and anhydrite (˜1 wt.%) are the mudstone crystalline minerals. Amorphous material is silica-rich (˜39 wt.% opal-A and/or high-SiO2 glass and opal-CT), volatile-bearing (16 wt.% mixed cation sulfates, phosphates, and chlorides-perchlorates-chlorates), and has minor TiO2 and Fe2O3T oxides (˜5 wt.%). Rietveld refinement yielded a monoclinic structural model for a well-crystalline tridymite, consistent with high formation temperatures. Terrestrial tridymite is commonly associated with silicic volcanism, and detritus from such volcanism in a “Lake Gale” catchment environment can account for Buckskin's tridymite, cristobalite, feldspar, and any residual high-SiO2 glass. These cogenetic detrital phases are possibly sourced from the Gale crater wall/rim/central peak. Opaline silica could form during diagenesis from high-SiO2 glass, as amorphous precipitated silica, or as a residue of acidic leaching in the sediment source region or at Marias Pass. The amorphous mixed-cation salts and oxides and possibly the crystalline magnetite (otherwise detrital) are primary precipitates and/or their diagenesis products derived from multiple infiltrations of aqueous solutions having variable compositions, temperatures, and acidities. Anhydrite is post lithification fracture/vein fill.

Silicic volcanism on Mars evidenced by tridymite in high-SiO2 sedimentary rock at Gale crater

PubMed Central

Morris, Richard V.; Vaniman, David T.; Blake, David F.; Gellert, Ralf; Chipera, Steve J.; Rampe, Elizabeth B.; Ming, Douglas W.; Morrison, Shaunna M.; Downs, Robert T.; Treiman, Allan H.; Yen, Albert S.; Grotzinger, John P.; Achilles, Cherie N.; Bristow, Thomas F.; Crisp, Joy A.; Des Marais, David J.; Farmer, Jack D.; Fendrich, Kim V.; Graff, Trevor G.; Morookian, John-Michael; Stolper, Edward M.; Schwenzer, Susanne P.

2016-01-01

Tridymite, a low-pressure, high-temperature (>870 °C) SiO2 polymorph, was detected in a drill sample of laminated mudstone (Buckskin) at Marias Pass in Gale crater, Mars, by the Chemistry and Mineralogy X-ray diffraction instrument onboard the Mars Science Laboratory rover Curiosity. The tridymitic mudstone has ∼40 wt.% crystalline and ∼60 wt.% X-ray amorphous material and a bulk composition with ∼74 wt.% SiO2 (Alpha Particle X-Ray Spectrometer analysis). Plagioclase (∼17 wt.% of bulk sample), tridymite (∼14 wt.%), sanidine (∼3 wt.%), cation-deficient magnetite (∼3 wt.%), cristobalite (∼2 wt.%), and anhydrite (∼1 wt.%) are the mudstone crystalline minerals. Amorphous material is silica-rich (∼39 wt.% opal-A and/or high-SiO2 glass and opal-CT), volatile-bearing (16 wt.% mixed cation sulfates, phosphates, and chlorides−perchlorates−chlorates), and has minor TiO2 and Fe2O3T oxides (∼5 wt.%). Rietveld refinement yielded a monoclinic structural model for a well-crystalline tridymite, consistent with high formation temperatures. Terrestrial tridymite is commonly associated with silicic volcanism, and detritus from such volcanism in a “Lake Gale” catchment environment can account for Buckskin’s tridymite, cristobalite, feldspar, and any residual high-SiO2 glass. These cogenetic detrital phases are possibly sourced from the Gale crater wall/rim/central peak. Opaline silica could form during diagenesis from high-SiO2 glass, as amorphous precipitated silica, or as a residue of acidic leaching in the sediment source region or at Marias Pass. The amorphous mixed-cation salts and oxides and possibly the crystalline magnetite (otherwise detrital) are primary precipitates and/or their diagenesis products derived from multiple infiltrations of aqueous solutions having variable compositions, temperatures, and acidities. Anhydrite is post lithification fracture/vein fill. PMID:27298370

High pressure-resistant nonincendive emulsion explosive

DOEpatents

Ruhe, Thomas C.; Rao, Pilaka P.

1994-01-01

An improved emulsion explosive composition including hollow microspheres/bulking agents having high density and high strength. The hollow microspheres/bulking agents have true particle densities of about 0.2 grams per cubic centimeter or greater and include glass, siliceous, ceramic and synthetic resin microspheres, expanded minerals, and mixtures thereof. The preferred weight percentage of hollow microspheres/bulking agents in the composition ranges from 3.0 to 10.0 A chlorinated paraffin oil, also present in the improved emulsion explosive composition, imparts a higher film strength to the oil phase in the emulsion. The emulsion is rendered nonincendive by the production of sodium chloride in situ via the decomposition of sodium nitrate, a chlorinated paraffin oil, and sodium perchlorate. The air-gap sensitivity is improved by the in situ formation of monomethylamine perchlorate from dissolved monomethylamine nitrate and sodium perchlorate. The emulsion explosive composition can withstand static pressures to 139 bars and dynamic pressure loads on the order of 567 bars.

Large moments in bcc FexCoyMnz ternary alloy thin films

NASA Astrophysics Data System (ADS)

Snow, R. J.; Bhatkar, H.; N'Diaye, A. T.; Arenholz, E.; Idzerda, Y. U.

2018-02-01

The elemental magnetic moments and the average atomic moment of 10-20 nm thick single crystal bcc (bct) FexCoyMnz films deposited on MgO(001) have been determined as a function of a broad range of compositions. Thin film epitaxy stabilized the bcc structure for 80% of the available ternary compositional space compared to only a 23% stability region for the bulk. The films that display ferromagnetism represent 60% of the available compositional possibilities compared to 25% for the bulk. A maximum average atomic moment of 3.25 ± 0.3 μB/atom was observed for a bcc Fe9Co62Mn29 film (well above the limit of the Slater-Pauling binary alloy curve of 2.45 μB/atom). The FexCoyMnz ternary alloys that exhibit high moments can only be synthesized as ultrathin films since the bcc structure is not stable in the bulk for those compositions.

Archean upper crust transition from mafic to felsic marks the onset of plate tectonics.

PubMed

Tang, Ming; Chen, Kang; Rudnick, Roberta L

2016-01-22

The Archean Eon witnessed the production of early continental crust, the emergence of life, and fundamental changes to the atmosphere. The nature of the first continental crust, which was the interface between the surface and deep Earth, has been obscured by the weathering, erosion, and tectonism that followed its formation. We used Ni/Co and Cr/Zn ratios in Archean terrigenous sedimentary rocks and Archean igneous/metaigneous rocks to track the bulk MgO composition of the Archean upper continental crust. This crust evolved from a highly mafic bulk composition before 3.0 billion years ago to a felsic bulk composition by 2.5 billion years ago. This compositional change was attended by a fivefold increase in the mass of the upper continental crust due to addition of granitic rocks, suggesting the onset of global plate tectonics at ~3.0 billion years ago. Copyright © 2016, American Association for the Advancement of Science.

Two cubesat mission to study the Didymos asteroid system

NASA Astrophysics Data System (ADS)

Wahlund, J.-E.; Vinterhav, E.; Trigo-Rodríguez, J. M.; Hallmann, M.; Barabash, S.; Ivchenko, N.

2015-10-01

Among the growing interest about asteroid impact hazard mitigation in our community the Asteroid Impact & Deflection Assessment (AIDA) mission will be the first space experiment to use a kinetic impactor to demonstrate its capability as reliable deflection system [1]. As a part of the AIDA mission, we have proposed a set of two three-axis stabilized 3U CubeSats (with up to 5 science sensors) to simultaneously rendezvous at close range (<500m) with both the primary and the secondary component of the Didymos asteroid system. The CubeSats will be hosted on the ESA component of the AIDA mission, the monitoring satellite AIM (Asteroid Impact Mission). The CubeSats will characterise the magnetization, the main bulk chemical composition and presence of volatiles as well as do superresolution surface imaging of the Didymos components. The CubeSats will also support the plume characterisation resulting from the DART impact (Double Asteroid Redirection Test, a NASA component of the AIDA mission) at much closer range than the AIM main spacecraft, and provide imaging, composition, and temperature of the plume material. At end of the mission, the two CubeSats can optionally land on one of the asteroids for continued science operation. The science sensors consist of a dual fluxgate magnetometer (MAG), one miniaturized volatile composition analyser (VCA), a narrow angle camera (NAC) and a Video Emission Spectrometer (VES) with a diffraction grating for allowing a sequential chemical study of the emission spectra associated with the impact flare and the expanding plume. Consequently, the different envisioned instruments onboard the CubeSats can provide significant insight into the complex response of asteroid materials during impacts that has been theoretically studied using different techniques [2]. The two CubeSats will remain stowed in CubeSat dispensers aboard the main AIM spacecraft. They will be deployed and commissioned before the AIM impactor reaches the secondary and record the impact event from a closer vantage point than the main spacecraft. The two CubeSats are equipped with relative navigation systems capable of estimating the spacecraft position relative to the asteroids and propulsion system that allow them to operate close to the asteroid bodies. The two CubeSats will rely on mapping data relayed via the AIM main spacecraft but operate autonomously and individually based on schedules and navigation maps uploaded from ground. AIDA's target is the binary Apollo asteroid 65803 Didymos that is also catalogued as Potentially Hazardous Asteroid (PHA) because it experiences close approaches to Earth. Didymos' primary has a diameter of ˜800 meters and the secondary is ˜150 m across. Both bodies are separated about 1.1 km [3]. The rotation period and asymmetry of the secondary object is unknown, and it might be tidally locked to the larger primary body. At least the primary body is expected to be associated with ordinary chondrite material, consisting mostly of silicates, and metal, but the earlier made Xk classification suggested a rubble-pile type with large amount of volatile content. The secondary companion spectral class is unknown, but the total mass of the system suggests that the secondary companion could be of similar class. Detailed empirical information on the physical properties of the Didymos asteroid system, in particular the magnetic field, the (mineralogical) surface composition, the internal composition via the bulk density, the ages of surface units through crater counts and other morphological surface features is valuable in order to make progress in the asteroid field of science. Furthermore, the periodic effect of such a close dynamic system in the presence and temporal displacement of the surface regolith is EPSC Abstracts Vol. 10, EPSC2015-698, 2015 European Planetary Science Congress 2015 c Author(s) 2015 EPSC European Planetary Science Congress unknown, and could be followed using close-up video systems provided by the CubeSats. In conclusion, the proposed two CubeSats as part of the AIDA mission can therefore contribute significantly, since they can monitor the Didymos asteroid components at a very close range around hundred meters, and at the same time monitor in-situ an impact plume when it is created.

Use of response surface methodology for the assessment of changes in the volatile composition of Moscato bianco (Vitis vinifera L.) grape berries during ripening.

PubMed

Torchio, Fabrizio; Giacosa, Simone; Vilanova, Mar; Río Segade, Susana; Gerbi, Vincenzo; Giordano, Manuela; Rolle, Luca

2016-12-01

The changes in the volatile composition of Moscato bianco grapes were evaluated during ripening. Grape berries were sampled for five weeks (16-20 °Brix) and sorted for each date in ten density classes (1.05-1.12g/cm(3)). The highest total concentration of free terpenes was found at 19.3 °Brix; however, total concentration of the bound fraction increased significantly throughout ripening. Response surface methodology was used to assess the simultaneous effect of sampling time and berry density on the volatile composition, which was satisfactorily fitted to regression models for some key terpene compounds. Total free and bound terpenes were more affected by grape density than by sampling date. The same behaviour was observed for free and bound linalool and bound nerol, whereas the stronger effect of sampling date was exhibited for bound t-rose oxide, c-rose oxide and geraniol. The results showed that the sampling strategy impacted strongly on the aroma quality of berries. Copyright © 2016 Elsevier Ltd. All rights reserved.

Differentiation of Wines Treated with Wood Chips Based on Their Phenolic Content, Volatile Composition, and Sensory Parameters.

PubMed

Kyraleou, Maria; Kallithraka, Stamatina; Chira, Kleopatra; Tzanakouli, Eleni; Ligas, Ioannis; Kotseridis, Yorgos

2015-12-01

The effects of both wood chips addition and contact time on phenolic content, volatile composition, color parameters, and organoleptic character of red wine made by a native Greek variety (Agiorgitiko) were evaluated. For this purpose, chips from American, French, Slavonia oak, and Acacia were added in the wine after fermentation. A mixture consisting of 50% French and 50% Americal oak chips was also evaluated. In an attempt to categorize wine samples, various chemical parameters of wines and sensory parameters were studied after 1, 2, and 3 mo of contact time with chips. The results showed that regardless of the type of wood chips added in the wines, it was possible to differentiate the samples according to the contact time based on their phenolic composition and color parameters. In addition, wood-extracted volatile compounds seem to be the critical parameter that could separate the samples according to the wood type. The wines that were in contact with Acacia and Slavonia chips could be separated from the rest mainly due to their distinct sensory characters. © 2015 Institute of Food Technologists®

Evolution of Volatile Emission in Rhus coriaria Organs During Different Stages of Growth and Evaluation of the Essential Oil Composition.

PubMed

Reidel, Rose Vanessa Bandeira; Cioni, Pier Luigi; Majo, Luigi; Pistelli, Luisa

2017-11-01

Rhus coriaria, also known as Sumac, has been traditionally used in many countries as spice, condiment, dying agent, and medicinal herb. The chemical composition of essential oils (EOs) and the volatile emissions from different organs of this species collected in Sicily (Italy) were analyzed by gas chromatography-flame ionization detection and gas chromatography/mass spectrometry. Monoterpene and sesquiterpene hydrocarbons were the most abundant class in the volatile emissions with β-caryophyllene and α-pinene were the main constituents in the majority of the examined samples. The EO composition was characterized by high amount of monoterpene and sesquiterpene hydrocarbons together with diterpenes. The main compounds in the EO obtained from the leaves and both stages of fruit maturation were cembrene and β-caryophyllene, while α-pinene and tridecanoic acid were the key compounds in the flower EO. All the data were submitted to multivariate statistical analysis showing many differences among the different plant parts and their ontogenetic stages. © 2017 Wiley-VHCA AG, Zurich, Switzerland.

ISOTOPIC (14C) AND CHEMICAL COMPOSITION OF ATMOSPHERIC VOLATILE ORGANIC COMPOUND FRACTIONS - PRECURSORS TO OZONE FORMATION

EPA Science Inventory

Atmospheric volatile organic compounds (VOCs) are an important factor in the production of ozone near ground level [3]. Many hydrocarbons originate from auto exhaust. However, a number of VOCs, e.g., isoprene, are known to be natural in origin. To develop reliable models for un...

Dissolution of bulk specimens of silicon nitride

NASA Technical Reports Server (NTRS)

Davis, W. F.; Merkle, E. J.

1981-01-01

An accurate chemical characterization of silicon nitride has become important in connection with current efforts to incorporate components of this material into advanced heat engines. However, there are problems concerning a chemical analysis of bulk silicon nitride. Current analytical methods require the pulverization of bulk specimens. A pulverization procedure making use of grinding media, on the other hand, will introduce contaminants. A description is given of a dissolution procedure which overcomes these difficulties. It has been found that up to at least 0.6 g solid pieces of various samples of hot pressed and reaction bonded silicon nitride can be decomposed in a mixture of 3 mL hydrofluoric acid and 1 mL nitric acid overnight at 150 C in a Parr bomb. High-purity silicon nitride is completely soluble in nitric acid after treatment in the bomb. Following decomposition, silicon and hydrofluoric acid are volatilized and insoluble fluorides are converted to a soluble form.

Chemical Composition and Character Impact Odorants in Volatile Oils from Edible Mushrooms.

PubMed

Usami, Atsushi; Motooka, Ryota; Nakahashi, Hiroshi; Marumoto, Shinsuke; Miyazawa, Mitsuo

2015-11-01

The aim of this study was to investigate the chemical composition and the odor-active components of volatile oils from three edible mushrooms, Pleurotus ostreatus, Pleurotus eryngii, and Pleurotus abalonus, which are well-known edible mushrooms. The volatile components in these oils were extracted by hydrodistillation and identified by GC/MS, GC-olfactometry (GC-O), and aroma extract dilution analysis (AEDA). The oils contained 40, 20, and 53 components, representing 83.4, 86.0, and 90.8% of the total oils in P. ostreatus, P. eryngii, and P. abalonus, respectively. Odor evaluation of the volatile oils from the three edible mushrooms was also carried out using GC-O, AEDA, and odor activity values, by which 13, eight, and ten aroma-active components were identified in P. ostreatus, P. eryngii, and P. abalonus, respectively. The most aroma-active compounds were C8 -aliphatic compounds (oct-1-en-3-ol, octan-3-one, and octanal) and/or C9 -aliphatic aldehydes (nonanal and (2E)-non-2-enal). Copyright © 2015 Verlag Helvetica Chimica Acta AG, Zürich.

The XRD Amorphous Component in John Klein Drill Fines at Yellowknife Bay, Gale Crater, Mars

NASA Technical Reports Server (NTRS)

Morris, Richard V.; Ming,, Douglas W.; Blake, David; Vaniman, David; Bish, David L; Chipera, Steve; Downs, Robert; Morrison, Shaunna; Gellert, Ralf; Campbell, Iain;

Exploring the Effects of Geographical Origin on the Chemical Composition and Quality Grading of Vitis vinifera L. cv. Chardonnay Grapes.

PubMed

Gambetta, Joanna M; Cozzolino, Daniel; Bastian, Susan E P; Jeffery, David W

2017-01-31

The relationship between berry chemical composition, region of origin and quality grade was investigated for Chardonnay grapes sourced from vineyards located in seven South Australian Geographical Indications (GI). Measurements of basic chemical parameters, amino acids, elements, and free and bound volatiles were conducted for grapes collected during 2015 and 2016. Multiple factor analysis (MFA) was used to determine the sets of data that best discriminated each GI and quality grade. Important components for the discrimination of grapes based on GI were 2-phenylethanol, benzyl alcohol and C6 compounds, as well as Cu, Zn, and Mg, titratable acidity (TA), total soluble solids (TSS), and pH. Discriminant analysis (DA) based on MFA results correctly classified 100% of the samples into GI in 2015 and 2016. Classification according to grade was achieved based on the results for elements such as Cu, Na, Fe, volatiles including C6 and aryl alcohols, hydrolytically-released volatiles such as (Z)-linalool oxide and vitispirane, pH, TSS, alanine and proline. Correct classification through DA according to grade was 100% for both vintages. Significant correlations were observed between climate, GI, grade, and berry composition. Climate influenced the synthesis of free and bound volatiles as well as amino acids, sugars, and acids, as a result of higher temperatures and precipitation.

Volatile profiles and chromatic characteristics of red wines produced with Starmerella bacillaris and Saccharomyces cerevisiae.

PubMed

Englezos, Vasileios; Rantsiou, Kalliopi; Cravero, Francesco; Torchio, Fabrizio; Giacosa, Simone; Ortiz-Julien, Anne; Gerbi, Vincenzo; Rolle, Luca; Cocolin, Luca

2018-07-01

The use of mixed fermentations with Starmerella bacillaris and Saccharomyces cerevisiae is gaining attention in recent years due to their ability to modulate the metabolites production of enological interest. In the present study, four of the most popular planted red grape varieties (Cabernet sauvignon, Merlot, Pinot noir and Shiraz) were fermented using the aforementioned species and two different inoculation protocols (inoculation of S. cerevisiae after 24 and 48 h from the Starm. bacillaris inoculation), in order to evaluate their impact on the volatile composition and chromatic characteristics of wines. Analysis from chemical composition showed that titratable acidity and glycerol content exhibited marked differences among wines after fermentation. For volatile compounds, mixed fermented wines using an inoculation delay of 48 h led to reduction of volatile compounds (mainly esters). A shorter 24 h delay produced wines with higher values of color intensity than pure fermented wines. The differences observed between the inoculation protocols can be explained by the growth dynamics of both species during fermentation. These findings suggest that mixed fermentations posed a great potential in reducing metabolites which are considered negative for wine quality (mainly ethyl acetate and volatile fatty acids) and with an improvement of the chromatic profile of the wines. Copyright © 2018 Elsevier Ltd. All rights reserved.

Effects of irrigation regimes on fatty acid composition, antioxidant and antifungal properties of volatiles from fruits of Koroneiki cultivar grown under Tunisian conditions.

PubMed

Brahmi, Faten; Chehab, Hechmi; Flamini, Guido; Dhibi, Madiha; Issaoui, Manel; Mastouri, Maha; Hammami, Mohamed

2013-11-15

The olive tree is generally grown under rain-fed conditions. However, since the yield response to irrigation is great, even with low amounts of water, there is increasing interest in irrigated agriculture. The main goal of this study was, therefore, to investigate the effect of irrigation regimes on olive (Olea europaea L., cv. Koroneiki) obtained from an intensively-managed orchard in a semi-arid area with a Mediterranean climate in Tunisia. Different irrigation treatments 50% ETc, 75% ETc and 100% ETc were applied to the olive orchard. Accordingly, the effects of three irrigation regimes on volatile compounds, fatty acid composition and biological activities of Koroneiki cultivar were studied. The total profile of the volatile constituents of all samples revealed the predominance of 3-ethenylpyridine (from 14.9-19.6%), phenylethyl alcool (from 7.8-19.2%) and benzaldehyde (from 9.0 to 13.8%). During watering level treatments studied, the major fatty acids were oleic, palmitic and linoleic. Antioxidant activity of the fresh fruit volatiles cultivated at a watering level of 100% ETc was higher than that obtained under 50 and 75% Etc. The results of antifungal activity showed that the fruits volatiles of the three irrigation treatments had varying degrees of growth inhibition against the microorganisms tested.

Silicon in Mars' Core: A Prediction Based on Mars Model Using Nitrogen and Oxygen Isotopes in SNC Meteorites

NASA Technical Reports Server (NTRS)

Mohapatra, R. K.; Murty, S. V. S.

2002-01-01

Chemical and (oxygen) isotopic compositions of SNC meteorites have been used by a number of workers to infer the nature of precursor materials for the accretion of Mars. The idea that chondritic materials played a key role in the formation of Mars has been the central assumption in these works. Wanke and Dreibus have proposed a mixture of two types of chondritic materials, differing in oxygen fugacity but having CI type bulk chemical composition for the nonvolatile elements, for Mars' precursor. But a number of studies based on high pressure and temperature melting experiments do not favor a CI type bulk planet composition for Mars, as it predicts a bulk planet Fe/Si ratio much higher than that reported from the recent Pathfinder data. Oxygen forms the bulk of Mars (approximately 40% by wt.) and might provide clues to the type of materials that formed Mars. But models based on the oxygen isotopic compositions of SNC meteorites predict three different mixtures of precursor materials for Mars: 90% H + 10% CM, 85% H + 11% CV + 4% CI and 45% EH + 55% H. As each of these models has been shown to be consistent with the bulk geophysical properties (such as mean density, and moment of inertia factor) of Mars, the nature of the material that accreted to form Mars remains ambiguous.

Martian regolith in Elephant Moraine 79001 shock melts? Evidence from major element composition and sulfur speciation

NASA Astrophysics Data System (ADS)

Walton, E. L.; Jugo, P. J.; Herd, C. D. K.; Wilke, M.

2010-08-01

Shock veins and melt pockets in Lithology A of Martian meteorite Elephant Moraine (EETA) 79001 have been investigated using electron microprobe (EM) analysis, petrography and X-ray Absorption Near Edge Structure (XANES) spectroscopy to determine elemental abundances and sulfur speciation (S 2- versus S 6+). The results constrain the materials that melted to form the shock glasses and identify the source of their high sulfur abundances. The XANES spectra for EETA79001 glasses show a sharp peak at 2.471 keV characteristic of crystalline sulfides and a broad peak centered at 2.477 keV similar to that obtained for sulfide-saturated glass standards analyzed in this study. Sulfate peaks at 2.482 keV were not observed. Bulk compositions of EETA79001 shock melts were estimated by averaging defocused EM analyses. Vein and melt pocket glasses are enriched in Al, Ca, Na and S, and depleted in Fe, Mg and Cr compared to the whole rock. Petrographic observations show preferential melting and mobilization of plagioclase and pyrrhotite associated with melt pocket and vein margins, contributing to the enrichments. Estimates of shock melt bulk compositions obtained from glass analyses are biased towards Fe- and Mg- depletions because, in general, basaltic melts produced from groundmass minerals (plagioclase and clinopyroxene) will quench to a glass, whereas ultramafic melts produced from olivine and low-Ca pyroxene megacrysts crystallize during the quench. We also note that the bulk composition of the shock melt pocket cannot be determined from the average composition of the glass but must also include the crystals that grew from the melt - pyroxene (En 72-75Fs 20-21Wo 5-7) and olivine (Fo 75-80). Reconstruction of glass + crystal analyses gives a bulk composition for the melt pocket that approaches that of lithology A of the meteorite, reflecting bulk melting of everything except xenolith chromite. Our results show that EETA79001 shock veins and melt pockets represent local mineral melts formed by shock impedance contrasts, which can account for the observed compositional anomalies compared to the whole rock sample. The observation that melts produced during shock commonly deviate from the bulk composition of the host rock has been well documented from chondrites, rocks from terrestrial impact structures and other Martian meteorites. The bulk composition of shock melts reflects the proportions of minerals melted; large melt pockets encompass more minerals and approach the whole rock whereas small melt pockets and thin veins reflect local mineralogy. In the latter, the modal abundance of sulfide globules may reach up to 15 vol%. We conclude the shock melt pockets in EETA79001 lithology A contain no significant proportion of Martian regolith.

Exploring the Utilization of Low-Pressure, Piston-Cylinder Experiments to Determine the Bulk Compositions of Finite, Precious Materials

NASA Technical Reports Server (NTRS)

Vander Kaaden, K. E.; McCubbin, F. M.; Harrington, A. D.

2017-01-01

Determining the bulk composition of precious materials with a finite mass (e.g., meteorite samples) is extremely important in the fields of Earth and Planetary Science. From meteorite studies we are able to place constraints on large scale planetary processes like global differentiation and subsequent volcanism, as well as smaller scale processes like crystallization in a magma chamber or sedimentary compaction at the surface. However, with meteorite samples in particular, far too often we are limited by how precious the sample is as well as its limited mass. In this study, we have utilized aliquots of samples previously studied for toxicological hazards, including both the fresh samples (lunar mare basalt NWA 4734, lunar regolith breccia NWA 7611, martian basalt Tissint, martian regolith breccia NWA 7034, a vestian basalt Berthoud, a vestian regolith breccia NWA 2060, and a terrestrial mid-ocean ridge basalt (MORB)), and those that underwent iron leaching (Tissint, NWA 7034, NWA 4734, MORB). With these small masses of material, we performed low pressure (approx. 0.75 GPa), high temperature (greater than 1600 degrees Celsius) melting experiments. Each sample was analyzed using a JEOL 8530F electron microprobe to determine the bulk composition of the materials that were previously examined. When available, the results of our microprobe data were compared with bulk rock compositions in the literature. The results of this study show that with this technique, only approx. 50 mg of sample is required to accurately determine the bulk composition of the materials of interest.

Diagenetic Mineralogy at Gale Crater, Mars

NASA Technical Reports Server (NTRS)

Vaniman, David; Blake, David; Bristow, Thomas F.; Chipera, Steve; Gellert, Ralf; Ming, Douglas; Morris, Richard; Rampe, E. B.; Rapin, William

2015-01-01

Three years into exploration of sediments in Gale crater on Mars, the Mars Science Laboratory rover Curiosity has provided data on several modes and episodes of diagenetic mineral formation. Curiosity determines mineralogy principally by X-ray diffraction (XRD), but with supporting data from thermal-release profiles of volatiles, bulk chemistry, passive spectroscopy, and laser-induced breakdown spectra of targeted spots. Mudstones at Yellowknife Bay, within the landing ellipse, contain approximately 20% phyllosilicate that we interpret as authigenic smectite formed by basalt weathering in relatively dilute water, with associated formation of authigenic magnetite as in experiments by Tosca and Hurowitz [Goldschmidt 2014]. Varied interlayer spacing of the smectite, collapsed at approximately 10 A or expanded at approximately 13.2 A, is evidence of localized diagenesis that may include partial intercalation of metal-hydroxyl groups in the approximately 13.2 A material. Subsequent sampling of stratigraphically higher Windjana sandstone revealed sediment with multiple sources, possible concentration of detrital magnetite, and minimal abundance of diagenetic minerals. Most recent sampling has been of lower strata at Mount Sharp, where diagenesis is widespread and varied. Here XRD shows that hematite first becomes abundant and products of diagenesis include jarosite and cristobalite. In addition, bulk chemistry identifies Mg-sulfate concretions that may be amorphous or crystalline. Throughout Curiosity's traverse, later diagenetic fractures (and rarer nodules) of mm to dm scale are common and surprisingly constant and simple in Ca-sulfate composition. Other sulfates (Mg,Fe) appear to be absent in this later diagenetic cycle, and circumneutral solutions are indicated. Equally surprising is the rarity of gypsum and common occurrence of bassanite and anhydrite. Bassanite, rare on Earth, plays a major role at this location on Mars. Dehydration of gypsum to bassanite in the dry atmosphere of Mars has been proposed but considered unlikely based on lab studies of dehydration kinetics in powdered samples. Dehydration is even less likely for bulk vein samples, as lab data show dehydration rates one to two orders of magnitude slower in bulk samples than in powders. On Mars, exposure ages of 100 Ma or more may be a significant factor in dehydration of hydrous phases.

Evaluating the influence of chemical weathering on the composition of the continental crust using lithium and its isotopes

NASA Astrophysics Data System (ADS)

Rudnick, R. L.; Liu, X.

2011-12-01

The continental crust has an "intermediate" bulk composition that is distinct from primary melts of peridotitic mantle (basalt or picrite). This mismatch between the "building blocks" and the "edifice" of the continental crust points to the operation of processes that preferentially remove mafic to ultramafic material from the continents. Such processes include lower crustal recycling (via density foundering or lower crustal subduction - e.g., relamination, Hacker et al., 2011, EPSL), generation of evolved melts via slab melting, and/or chemical weathering. Stable isotope systems document the influence of chemical weathering on the bulk crust composition: the oxygen isotope composition of the bulk crust is distinctly heavier than that of primary, mantle-derived melts (Simon and Lecuyer, 2005, G-cubed) and the Li isotopic composition of the bulk crust is distinctly lighter than that of mantle-derive melts (Teng et al., 2004, GCA; 2008, Chem. Geol.). Both signatures mark the imprint of chemical weathering on the bulk crust composition. Here, we use a simple mass balance model for lithium inputs and outputs from the continental crust to quantify the mass lost due to chemical weathering. We find that a minimum of 15%, a maximum of 60%, and a best estimate of ~40% of the original juvenile rock mass may have been lost via chemical weathering. The accumulated percentage of mass loss due to chemical weathering leads to an average global chemical weathering rate (CWR) of ~ 8×10^9 to 2×10^10 t/yr since 3.5 Ga, which is about an order of magnitude higher than the minimum estimates based on modern rivers (Gaillardet et al., 1999, Chem. Geol.). While we cannot constrain the exact portion of crustal mass loss via chemical weathering, given the uncertainties of the calculation, we can demonstrate that the weathering flux is non-zero. Therefore, chemical weathering must play a role in the evolution of the composition and mass of the continental crust.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

Nacre, also known as mother-of-pearl, is a biocomposite material that exhibits higher strength and fracture toughness than its component materials. It derives its strength from the brick-and-mortar layering of aragonite (CaCO{sub 3}) platelets and organic binder. It is believed that the protein binder helps redistribute the stress throughout all tablets for optimal mechanical performance. In this study, we attempt to measure the mechanical properties of aragonite within nacre and compare them to bulk aragonite and bulk nacre and understand the redistribution of stresses. Here we show that x-ray diffraction techniques are useful for isolating and measuring strain of crystallites withinmore » a composite material. Our results show that the apparent stiffness of aragonite varies with crystallographic directions and is higher than the stiffness of bulk nacre in all cases, meaning that aragonite tablets are exposed to less than the average bulk stress. The average force applied to the bulk sample is partitioned between the aragonite and the binder, so that the protein layer bears as much as 27.2% of the total applied force. Different crystallographic directions exhibit behaviors different than bulk aragonite or bulk nacre. These are related to texture of aragonite platelets (i.e. preferred orientations within nacre). By examining nacre, we can obtain a better understanding of the mechanical relationship between the ceramic and polymer in composite materials. We expect that x-ray diffraction will become the standard method for probing the mechanical properties of composite materials.« less

A Tale of “Two” Comets: The Primary Volatile Composition of Comet 2P/Encke Across Apparitions

NASA Astrophysics Data System (ADS)

Roth, Nathan X.; Gibb, Erika L.; Bonev, Boncho P.; DiSanti, Michael A.; Dello Russo, Neil; Vervack, Ronald J.; McKay, Adam J.; Kawakita, Hideyo

2017-10-01

2P/Encke is one of the most frequently observed comets in history, yet its highly favorable 2017 apparition allowed the first comprehensive comparison of primary volatile abundances in the same comet across multiple apparitions. It offered an opportunity to address pressing questions in cometary science, including investigating evolutionary and/or heliocentric distance effects on volatile production, sampling the hypervolatiles CO and CH4 in an ecliptic comet, and probing volatile release at small Rh (0.4 AU). The faint nature of ecliptic comets and low geocentric velocity during most apparitions make these observations in the near-infrared rare (in particular at small Rh) and of high scientific impact. On March 21, 22, and 25 we characterized the volatile composition of 2P post-perihelion using the high-resolution near-infrared iSHELL spectrograph at the 3 m NASA-IRTF on Maunakea, HI. We detected fluorescent emission from eight primary volatiles (H2O, CO, C2H6, CH3OH, CH4, H2CO, NH3, and HCN) and three secondary volatiles (OH*, NH2, and CN). Upper limits were derived for OCS and C2H2. We report rotational temperatures, production rates, and mixing ratios (with respect to H2O). Compared to median relative abundances in comets observed in the near-infrared to date, mixing ratios of trace gases in 2P/Encke are depleted for all detected species except HCN and NH3, which are consistent with the median. The detection of the hypervolatiles CO and CH4 is particularly notable given the paucity of measurements of these species in ecliptic comets. We observed significant differences in primary volatile composition compared to published pre-perihelion results from the 2003 apparition at larger Rh (~1.2 AU) (Radeva et al. 2013). We will discuss possible mechanisms for these effects, including asymmetry about perihelion in 2P (Sekanina 1988a, b), and discuss the results in the context of findings from the Rosetta mission and ground-based studies of comets. This work was supported by the NASA Earth and Space Science Fellowship, Solar Workings, Solar System Observations, and Astrobiology Programs, and NSF Solar and Planetary Science Grants.

SXRF determination of trace elements in chondrule rims in the unequilibrated CO3 chondrite, ALH A77307

NASA Technical Reports Server (NTRS)

Brearley, Adrian J.; Bajt, Sasa; Sutton, Steve R.; Papike, J. J.

1993-01-01

The concentrations of Ni, Cu, Zn, Ga, Ge, and Se in five chondrule rims in the CO3 chondrite ALH A77307 (3.0) using the synchrotron x-ray fluorescence (SXRF) microprobe at Brookhaven National Laboratory were determined. The data show that the trace element chemistry of rims on different chondrules is remarkably similar, consistent with data obtained for the major elements by electron microprobe. These results support the idea that rims are not genetically related to individual chondrules, but all sampled the same reservoir of homogeneously mixed dust. Of the trace elements analyzed Zn and Ga show depletions relative to CI chondrite values, but in comparison with bulk CO chondrites all the elements are enriched by approximately 1.5 to 3.5 x CO. The high concentrations of the highly volatile elements Se and Ga and moderately volatile Zn (1.5 to 2 x CO) in rims show that matrix is the major reservoir of volatile elements in ALH A77307.

The effect of genetically enriched (E)-β-ocimene and the role of floral scent in the attraction of the predatory mite Phytoseiulus persimilis to spider mite-induced volatile blends of torenia.

PubMed

Shimoda, Takeshi; Nishihara, Masahiro; Ozawa, Rika; Takabayashi, Junji; Arimura, Gen-ichiro

2012-03-01

Plants under herbivore attack emit mixtures of volatiles (herbivore-induced plant volatiles, HIPVs) that can attract predators of the herbivores. Although the composition of HIPVs should be critical for the attraction, most studies of transgenic plant-emitted volatiles have simply addressed the effect of trans-volatiles without embedding in other endogenous plant volatiles. We investigated the abilities of transgenic wishbone flower plants (Torenia hybrida and Torenia fournieri) infested with spider mites, emitting a trans-volatile ((E)-β-ocimene) in the presence or absence of endogenous volatiles (natural HIPVs and/or floral volatiles), to attract predatory mites (Phytoseiulus persimilis). In both olfactory- and glasshouse-based assays, P. persimilis females were attracted to natural HIPVs from infested wildtype (wt) plants of T. hybrida but not to those of T. fournieri. The trans-volatile enhanced the ability to attract P. persimilis only when added to an active HIPV blend from the infested transgenic T. hybrida plants, in comparison with the attraction by infested wt plants. Intriguingly, floral volatiles abolished the enhanced attractive ability of T. hybrida transformants, although floral volatiles themselves did not elicit any attraction or avoidance behavior. Predator responses to trans-volatiles were found to depend on various background volatiles (e.g. natural HIPVs and floral volatiles) endogenously emitted by the transgenic plants. © 2012 The Authors. New Phytologist © 2012 New Phytologist Trust.

Universal calibration of Raman spectroscopy for the analysis of volatiles in glasses of variable composition

NASA Astrophysics Data System (ADS)

Schiavi, Federica; Bolfan-Casanova, Nathalie

2017-04-01

The amount and distribution of volatiles (water, carbon dioxide …) in magmas represent key parameters for the understanding of magma processes and dynamics within volcanic plumbing systems. Micro-Raman spectroscopy is an excellent technique for accurate determination of volatile contents in magmas, as it combines several advantages. The technique is non-destructive and requires minimal sample preparation before the analysis. Its high lateral and in-depth spatial resolution is crucial for the study of small objects and samples that are chemically and texturally heterogeneous at the small scale (microns). Moreover, the high confocality allows analysis of sample regions not exposed to the surface and 3D mapping. We present a universal calibration of Raman spectroscopy for quantification of volatiles in silicate glasses. The proposed method is based on internal calibration, i.e., on the correlation between the glass water content and the ratio between the areas of the water and silicate Raman bands. Synthetic glasses with variable major element compositions (basaltic, andesitic, rhyolitic, dacitic ..) bearing different H2O (up to 7 wt%) and CO2 contents are used as standard glasses. Natural silicate glasses, mainly in the form of melt inclusions, are used to test the goodness of the proposed method. In addition to quantification of volatiles in glass, in bubble-bearing melt inclusions we perform micro-Raman spectroscopy investigation of gas-bearing bubbles for accurate determination of total volatile contents in melt inclusions.

Volatile compounds in samples of cork and also produced by selected fungi.

PubMed

Barreto, M C; Vilas Boas, L; Carneiro, L C; San Romão, M V

2011-06-22

The production of volatile compounds by microbial communities of cork samples taken during the cork manufacturing process was investigated. The majority of volatiles were found in samples collected at two stages: resting after the first boiling and nontreated cork disks. Volatile profiles produced by microbiota in both stages are similar. The releasable volatile compounds and 2,4,6-trichloroanisole (TCA) produced in cork-based culture medium by five isolated fungal species in pure and mixed cultures were also analyzed by gas chromatography coupled with mass spectrometry (GC-MS).The results showed that 1-octen-3-ol and esters of fatty acids (medium chain length C8-C20) were the main volatile compounds produced by either pure fungal species or their mixture. Apparently, Penicillium glabrum is the main contributor to the overall volatile composition observed in the mixed culture. The production of releasable TCA on cork cannot be attributed to any of the assayed fungal isolates.

Volatiles from roasted byproducts of the poultry-processing industry.

PubMed

Wettasinghe, M; Vasanthan, T; Temelli, F; Swallow, K

2000-08-01

Volatiles of roasted chicken breast muscle and byproducts, such as backbones, breastbones, spent bones, and skin, were investigated. Total volatile concentrations ranged from 2030 ppb in the roasted backbones to 4049 ppb in the roasted skin. The major classes of volatile compounds detected in roasted samples were aldehydes (648-1532 ppb) and alcohols (336-1006 ppb). Nitrogen- and/or sulfur-containing compounds were also detected in appreciable quantities (161-706 ppb) in all samples. For all samples, hexanal and 2-methyl-2-buten-1-ol were dominant among the aldehydes and alcohols, respectively. Among the nitrogen- and sulfur-containing compounds, Maillard reaction products, such as tetrahydropyridazines, piperidines, and thiazoles, were the major contributors to the total volatile content in all samples. The composition of volatiles observed in roasted byproducts was markedly different from that of the roasted breast muscle. Therefore, the blending of the byproducts in appropriate proportions or blending of volatile flavor extracts from different byproducts may be necessary to obtain an aroma that mimics roasted chicken aroma.

Composition of the earth's upper mantle. II - Volatile trace elements in ultramafic xenoliths

NASA Technical Reports Server (NTRS)

Morgan, J. W.; Wandless, G. A.; Petrie, R. K.; Irving, A. J.

1980-01-01

Radiochemical neutron activation analysis was used to determine the nine volatile elements Ag, Bi, Cd, In, Sb, Se, Te, Tl, and Zn in 19 ultramafic rocks, consisting mainly of spinel and garnet lherzolites. A sheared garnet lherzolite, PHN 1611, may approximate undepleted mantle material and tends to have a higher volatile element content than the depleted mantle material represented by spinel lherzolites. Comparisons of continental basalts with PHN 1611 and of oceanic ridge basalts with spinel lherzolites show similar basalt: source material partition factors for eight of the nine volatile elements, Sb being the exception. The strong depletion of Te and Se in the mantle, relative to lithophile elements of similar volatility, suggests that 97% of the earth's S, Se and Te may be in the outer core.

Study of the gas contents of rocks: An approach to the evolution of atmospheres on the earth and planets

NASA Technical Reports Server (NTRS)

Barker, C.

1972-01-01

A high vacuum system was built for extracting volatiles from rocks either by heating or crushing, and preliminary analyses of the volatiles were made for selected terrestrial basalts and granites. The apparatus and experimental procedures are described, and the major problems associated with water measurement and choice of argon to replace neon as the internal standard are discussed. Preliminary analyses of granites and basalts indicate the following: All analyses lie in the H2O-CO2-CO triangle on a C-H-O ternary diagram. The compositions of the volatiles plot in distinct, but overlapping, areas of the C-H-O diagram. Pre-Cambrian granites have a higher volatile content than younger granites. Continental basalts have a higher volatile content than oceanic basalts.

Hemispheric Dichotomy in Lithosphere Thickness on Mars Caused by Differences in Crustal Structure and Composition

NASA Astrophysics Data System (ADS)

Thiriet, Mélanie; Michaut, Chloé; Breuer, Doris; Plesa, Ana-Catalina

2018-04-01

Estimates of the Martian elastic lithosphere thickness suggest small values of ˜25 km during the Noachian for the southern hemisphere and a large present-day difference below the two polar caps (≥300 km in the north and >110 km in the south). In addition, young lava flows suggest that Mars has been volcanically active up to the recent past. We run Monte Carlo simulations using a 1-D parameterized thermal evolution model to investigate whether a north/south hemispheric dichotomy in crustal properties and composition can explain these constraints. Our results suggest that 55-65% of the bulk radioelement content are in the crust, and most of it (43-51%) in the southern one. The southern crust can be up to 480 kg/m3 less dense than the northern one and might contain a nonnegligible proportion of felsic rocks. Our models predict a dry mantle and a wet or dry crustal rheology today. This is consistent with a mantle depleted in radioelements and volatiles. We retrieve north/south surface heat flux of 17.1-19.5 mW/m2 and 24.8-26.5 mW/m2, respectively, and a large difference in lithospheric temperatures between the two hemispheres (170-304 K in the shallow mantle). This difference could leave a signature in the seismic signals measured by the future InSight mission.