Simulated space weathering of Fe- and Mg-rich aqueously altered minerals using pulsed laser irradiation

NASA Astrophysics Data System (ADS)

Kaluna, H. M.; Ishii, H. A.; Bradley, J. P.; Gillis-Davis, J. J.; Lucey, P. G.

2017-08-01

Simulated space weathering experiments on volatile-rich carbonaceous chondrites (CCs) have resulted in contrasting spectral behaviors (e.g. reddening vs bluing). The aim of this work is to investigate the origin of these contrasting trends by simulating space weathering on a subset of minerals found in these meteorites. We use pulsed laser irradiation to simulate micrometeorite impacts on aqueously altered minerals and observe their spectral and physical evolution as a function of irradiation time. Irradiation of the mineral lizardite, a Mg-phyllosilicate, produces a small degree of reddening and darkening, but a pronounced reduction in band depths with increasing irradiation. In comparison, irradiation of an Fe-rich aqueously altered mineral assemblage composed of cronstedtite, pyrite and siderite, produces significant darkening and band depth suppression. The spectral slopes of the Fe-rich assemblage initially redden then become bluer with increasing irradiation time. Post-irradiation analyses of the Fe-rich assemblage using scanning and transmission electron microscopy reveal the presence of micron sized carbon-rich particles that contain notable fractions of nitrogen and oxygen. Radiative transfer modeling of the Fe-rich assemblage suggests that nanometer sized metallic iron (npFe0) particles result in the initial spectral reddening of the samples, but the increasing production of micron sized carbon particles (μpC) results in the subsequent spectral bluing. The presence of npFe0 and the possible catalytic nature of cronstedtite, an Fe-rich phyllosilicate, likely promotes the synthesis of these carbon-rich, organic-like compounds. These experiments indicate that space weathering processes may enable organic synthesis reactions on the surfaces of volatile-rich asteroids. Furthermore, Mg-rich and Fe-rich aqueously altered minerals are dominant at different phases of the aqueous alteration process. Thus, the contrasting spectral slope evolution between the Fe- and Mg-rich samples in these experiments may indicate that space weathering trends of volatile-rich asteroids have a compositional dependency that could be used to determine the aqueous histories of asteroid parent bodies.

Aqueous Alteration and Shock Metamorphism of Antarctic CR Chondrites

NASA Technical Reports Server (NTRS)

Komatsu, M.; Fagan, T. J.; Yamaguchi, A.; Mikouchi, T.; Yasutake, M.; Zolensky, M. E.

2018-01-01

CR chondrites are the group of carbonaceous chondrites that best preserve records of formation of their components in the solar nebula. Although they are affected by aqueous alteration, many chondrules and CAIs are well-preserved, suggesting they have experienced little thermal metamorphism. We have been investigating the petrologic variations among the CR chondrites in the NIPR Antarctic meteorite collection. We focused particular attention on the petrology of amoeboid olivine aggregates (AOAs) in order to understand secondary alteration on the CR chondrite parent body. AOAs are composed of fine-grained forsteritic olivine and refractory minerals formed by condensation in the solar nebula, and can be used as sensitive indicators of secondary alteration processes.

The Origin of Dark Inclusions in Allende: New Evidence from Lithium Isotopes

NASA Technical Reports Server (NTRS)

Sephton, Mark A.; James, Rachael H.; Zolensky, Michael E.

2006-01-01

Aqueous and thermal processing of primordial material occurred prior to and during planet formation in the early solar system. A record of how solid materials were altered at this time is present in the carbonaceous chondrites, which are naturally delivered fragments of primitive asteroids. It has been proposed that some materials, such as the clasts termed dark inclusions found in type III chondrites, suggest a sequence of aqueous and thermal events. Lithium isotopes (Li-6 and Li-7) can reveal the role of liquid water in dark inclusion history. During aqueous alteration, Li-7 passes preferentially into solution leaving Li-6 behind in the solid phase and, consequently, any relatively extended periods of interaction with Li-7-rich fluids would have left the dark inclusions enriched in the heavier isotope when compared to the meteorite as a whole. Our analyses of lithium isotopes in Allende and its dark inclusions reveal marked isotopic homogeneity and no evidence of greater levels of aqueous alteration in dark inclusion history.

Synthesis of Amino Acid Precursors with Organic Solids in Planetesimals with Liquid Water

NASA Technical Reports Server (NTRS)

Kebukawa, Y; Misawa, S.; Matsukuma, J.; Chan, Q. H. S.; Kobayashi, J.; Tachibana, S.; Zolensky, M. E.

2017-01-01

Amino acids are important ingredients of life that would have been delivered to Earth by extraterrestrial sources, e.g., comets and meteorites. Amino acids are found in aqueously altered carbonaceous chondrites in good part in the form of precursors that release amino acids after acid hydrolysis. Meanwhile, most of the organic carbon (greater than 70 weight %) in carbonaceous chondrites exists in the form of solvent insoluble organic matter (IOM) with complex macromolecular structures. Complex macromolecular organic matter can be produced by either photolysis of interstellar ices or aqueous chemistry in planetesimals. We focused on the synthesis of amino acids during aqueous alteration, and demonstrated one-pot synthesis of a complex suite of amino acids simultaneously with IOM via hydrothermal experiments simulating the aqueous processing

Compositional studies of primitive asteroids

NASA Technical Reports Server (NTRS)

Vilas, Faith

1991-01-01

Primitive asteroids in the solar system (C, P, D class and associated subclasses) are believed to have undergone less thermal processing compared with the differential (S class) asteroids. Telescopic spectra of C class asteroids show effects of aqueous alteration products produced when heating of the asteroids was sufficient to melt surface water, but not strong enough to produce differentiation. Spectrum analysis of P and D class asteroids suggests that aqueous alteration terminated in the outer belt and did not operate at the distance of Jupiter's orbit.

Low-temperature aqueous alteration on the CR chondrite parent body: Implications from in situ oxygen-isotope analyses

NASA Astrophysics Data System (ADS)

Jilly-Rehak, Christine E.; Huss, Gary R.; Nagashima, Kazu; Schrader, Devin L.

2018-02-01

The presence of hydrated minerals in chondrites indicates that water played an important role in the geologic evolution of the early Solar System; however, the process of aqueous alteration is still poorly understood. Renazzo-like carbonaceous (CR) chondrites are particularly well-suited for the study of aqueous alteration. Samples range from being nearly anhydrous to fully altered, essentially representing snapshots of the alteration process through time. We studied oxygen isotopes in secondary-minerals from six CR chondrites of varying hydration states to determine how aqueous fluid conditions (including composition and temperature) evolved on the parent body. Secondary minerals analyzed included calcite, dolomite, and magnetite. The O-isotope composition of calcites ranged from δ18O ≈ 9 to 35‰, dolomites from δ18O ≈ 23 to 27‰, and magnetites from δ18O ≈ -18 to 5‰. Calcite in less-altered samples showed more evidence of fluid evolution compared to heavily altered samples, likely reflecting lower water/rock ratios. Most magnetite plotted on a single trend, with the exception of grains from the extensively hydrated chondrite MIL 090292. The MIL 090292 magnetite diverges from this trend, possibly indicating an anomalous origin for the meteorite. If magnetite and calcite formed in equilibrium, then the relative 18O fractionation between them can be used to extract the temperature of co-precipitation. Isotopic fractionation in Al Rais carbonate-magnetite assemblages revealed low precipitation temperatures (∼60 °C). Assuming that the CR parent body experienced closed-system alteration, a similar exercise for parallel calcite and magnetite O-isotope arrays yields "global" alteration temperatures of ∼55 to 88 °C. These secondary mineral arrays indicate that the O-isotopic composition of the altering fluid evolved upon progressive alteration, beginning near the Al Rais water composition of Δ17O ∼ 1‰ and δ18O ∼ 10‰, and becoming increasingly 16O-enriched toward a final fluid composition of Δ17O ∼ -1.2‰ and δ18O ∼ -15‰.

A New Modal Analysis Method to put Constraints on the Aqueous Alteration of CR Chondrites and Estimate the Unaltered CR Composition

NASA Technical Reports Server (NTRS)

Perronnet, M.; Zolensky, M. E.; Gounelle, M.; Schwandt, C. S.

2007-01-01

CR carbonaceous chondrites are of the major interest since they contain one of the most primitive organic matters. However, aqueous alteration has more or less overprinted their original features in a way that needed to be assessed. That was done in the present study by comparing the mineralogy of the most altered CR1 chondrite, GRO 95577, to a less altered CR2, Renazzo. Their modal analyses were achieved thanks to a new method, based on X-ray elemental maps acquired on electron microprobe, and on IDL image treatment. It allowed the collection of new data on the composition of Renazzo and confirmed the classification of GRO 95577 as a CR1. New alteration products for CRs, vermiculite and clinochlore, were observed. The homogeneity of the Fe-poor clays in the CR1 and the distinctive matrix composition in the two chondrites suggest a wide-range of aqueous alteration on CRs. The preservation of the outlines of the chondrules in GRO 95577 and the elemental transfers of Al, Fe and Ca throughout the chondrule and of Fe and S from the matrix to the chondrule favor the idea of an asteroidal location of the aqueous alteration. From their mineralogical descriptions and modal abundances, the element repartitions in Renazzo and GRO 95577 were computed. It indicates a possible relationship between these two chondrites via an isochemical alteration process. Knowing the chemical reactions that occurred during the alteration, it was thus possible to decipher the mineralogical modal abundances in the unaltered CR body.

A New Modal Analysis Method to put Constraints on the Aqueous Alteration of CR Chondrites and Estimate the Unaltered CR Composition

NASA Technical Reports Server (NTRS)

Perronnet, M.; Zolensky, M. E.; Gounelle, M.; Schwandt, C. S.

2007-01-01

carbonaceous chondrites are of the major interest since they contain one of the most primitive organic matters. However, aqueous alteration has more or less overprinted their original features in a way that needed to be assessed. That was done in the present study by comparing the mineralogy of the most altered CR1 chondrite, GRO 95577, to a less altered CR2, Renazzo. Their modal analyses were achieved thanks to a new method, based on X-ray elemental maps acquired on electron microprobe, and on IDL image treatment. It allowed the collection of new data on the composition of Renazzo and confirmed the classification of GRO 95577 as a CR1. New alteration products for CRs, vermiculite and clinochlore, were observed. The homogeneity of the Fe-poor clays in the CR1 and the distinctive matrix composition in the two chondrites suggest a wide-range of aqueous alteration on CRs. The preservation of the outlines of the chondrules in GRO 95577 and the elemental transfers of Al, Fe and Ca throughout the chondrule and of Fe and S from the matrix to the chondrule favor the idea of an asteroidal location of the aqueous alteration. From their mineralogical descriptions and modal abundances, the element repartitions in Renazzo and GRO 95577 were computed. It indicates a possible relationship between these two chondrites via an isochemical alteration process. Knowing the chemical reactions that occurred during the alteration, it was thus possible to decipher the mineralogical modal abundances in the unaltered CR body.

An Overview of Orbital Detections of Hydrated Silica and Silica-Rich Rocks on Mars

NASA Astrophysics Data System (ADS)

Sun, V. Z.; Milliken, R.

2016-12-01

Early predictions of high-silica phases on Mars have been confirmed by numerous orbital observations throughout the past 15 years and supported by recent rover and meteorite investigations. Orbital spectroscopy at visible-near-IR (CRISM/OMEGA) and thermal IR (TES/THEMIS) wavelengths has established the presence of aqueously formed hydrated silica across the planet as well as regional silica-rich rocks of igneous origin. TES data provided the first indications of widespread silica enrichment in the northern lowlands, which were debated to represent either andesite or altered basalt on the basis of spectral and geologic arguments. Since then, more localized occurrences of primary silicic lithologies have suggested that igneous processes on Mars may have been more diverse and complex than previously recognized. CRISM and OMEGA data also reveal numerous occurrences of hydrated silica on the Martian surface, likely reflecting primary chemical precipitates or secondary processes such as aqueous alteration or diagenesis. These detections have been associated with fluvial landforms, volcanic settings, uplifted central peak rocks, and mobile sediments, suggesting a variety of formation mechanisms. These silica phases and their colocation with other alteration products such as clays and sulfates reveal aqueous environments that may have been acidic, alkaline, or alternatingly both through space and time. Although there is an apparent prevalence of geochemically immature silica (e.g., glass or opal-A) indicating limited aqueous alteration, several instances of more mature silica (e.g., opal-CT or quartz) point to locales that may have experienced periods of prolonged water-rock interaction. This presentation will give an overview of the distribution and variety of these high-silica phases as seen from orbital datasets and discuss their implications for the magmatic and aqueous history of Mars.

Bleached chondrules: Evidence for widespread aqueous processes on the parent asteroids of ordinary chondrites

USGS Publications Warehouse

Grossman, J.N.; Alexander, C.M. O'D.; Wang, Jingyuan; Brearley, A.J.

2000-01-01

We present the first detailed study of a population of texturally distinct chondrules previously described by Kurat (1969), Christophe Michel-Levy (1976), and Skinner et al. (1989) that are sharply depleted in alkalis and Al in their outer portions. These 'bleached' chondrules, which are exclusively radial pyroxene and cryptocrystalline in texture, have porous outer zones where mesostasis has been lost. Bleached chondrules are present in all type 3 ordinary chondrites and are present in lower abundances in types 4-6. They are most abundant in the L and LL groups, apparently less common in H chondrites, and absent in enstatite chondrites. We used x-ray mapping and traditional electron microprobe techniques to characterize bleached chondrules in a cross section of ordinary chondrites. We studied bleached chondrules from Semarkona by ion microprobe for trace elements and H isotopes, and by transmission electron microscopy. Chondrule bleaching was the result of low-temperature alteration by aqueous fluids flowing through fine-grained chondrite matrix prior to thermal metamorphism. During aqueous alteration, interstitial glass dissolved and was partially replaced by phyllosilicates, troilite was altered to pentlandite, but pyroxene was completely unaffected. Calcium-rich zones formed at the inner margins of the bleached zones, either as the result of the early stages of metamorphism or because of fluid-chondrule reaction. The mineralogy of bleached chondrules is extremely sensitive to thermal metamorphism in type 3 ordinary chondrites, and bleached zones provide a favorable location for the growth of metamorphic minerals in higher petrologic types. The ubiquitous presence of bleached chondrules in ordinary chondrites implies that they all experienced aqueous alteration early in their asteroidal histories, but there is no relationship between the degree of alteration and metamorphic grade. A correlation between the oxidation state of chondrite groups and their degree of aqueous alteration is consistent with the source of water being either accreted ices or water released during oxidation of organic matter. Ordinary chondrites were probably open systems after accretion, and aqueous fluids may have carried volatile elements with them during dehydration. Individual radial pyroxene and cryptocrystalline chondrules were certainly open systems in all chondrites that experienced aqueous alteration leading to bleaching.

Potentially Habitable Ancient Environments in Gusev Crater, Mars

NASA Technical Reports Server (NTRS)

DesMarais, David J.

2010-01-01

Habitable environments must sustain liquid water at least intermittently and also provide both chemical building blocks and useful sources of energy for life. Observations by Spirit rover indicate that conditions have probably been too dry to sustain life, at least since the emplacement of the extensive basalts that underlie the plains around the Columbia Memorial Station landing site. Local evidence of relatively minor aqueous alteration [1] probably occurred under conditions where the activity of water was too low to sustain biological processes as we know them. In contrast, multiple bedrock units in West Spur and Husband Hill in the Columbia Hills have been extensively altered. Patterns of elemental abundances are consistent with aqueous processes involving migrating fluids [2]. Fe in several of these units has been extensively oxidized [3]. Conceivably any microbiota present during the aqueous alteration of these rocks might have obtained energy from Fe oxidation. Spirit discovered olivine-rich ultramafic rocks during her descent from Husband Hill southward into Inner Basin. Alteration of similar ultramafic rocks on Earth can yield H2 that can provide both energy and reducing power for microorganisms. Spirit's discovery of deposits rich in ferric sulfate is consistent with the aqueous dissolution and/or alteration of olivine under acidic conditions [2] such as those associated with hydrothermal activity. The oxidation of iron and sulfur that can accompany such activity can be an energy source for life. Hydrothermal systems on Earth that sustain either acidic [4] or neutral to alkaline fluids [5] have been shown to provide this energy. Collectively the observations by Spirit rover are consistent with the possibility that habitable environments existed in Gusev crater at least intermittently in the distant geologic past.

Aqueous organic geochemistry at high temperature/high pressure

NASA Technical Reports Server (NTRS)

Simoneit, Bernd R. T.

1992-01-01

A description of the fate and chemical alterations of organic matter under hydrothermal conditions is given, with a brief overview of the geographic localities where these processes have been investigated to date. Two major aspects are examined: (1) alteration and degradation processes and reactions, both reductive and oxidative; and (2) synthesis processes and reactions which are primarily reductive. Examples of industrial applications of the related supercritical fluid technology are discussed.

Geochemical and Mineralogical Indicators for Aqueous Processes on the West Spur of the Columbia Hills in Gusev Crater

NASA Technical Reports Server (NTRS)

Ming, D. W.; Morris, R. V.; Gellert, R.; Yen, A.; Bell, J. F., III; Blaney, D.; Christensen, P. R.; Crumpler, L.; Chu, P.; Farrand, W. H.

2005-01-01

The primary objective of the MER Spirit and Opportunity Rovers is to identify and investigate rocks, outcrops, and soils that have the highest possible chance of preserving evidence of water activity on Mars. The Athena Science Instrument Payload onboard the two rovers has provided geochemical and mineralogical information that indicates a variety of aqueous processes and various degrees of alteration at the two landing sites.

Evidence of Chemical Cloud Processing from In Situ Measurements in the Polluted Marine Environment

NASA Astrophysics Data System (ADS)

Hudson, J. G.; Noble, S. R., Jr.

2017-12-01

Chemical cloud processing alters activated cloud condensation nuclei (CCN). Aqueous oxidation of trace gases dissolved within cloud droplets adds soluble material. As most cloud droplets evaporate, the residual material produces CCN that are larger and with a different hygroscopicity (κ). This improves the CCN, lowering the critical supersaturation (Sc), making it more easily activated. This process separates the processed (accumulation) and unprocessed (Aitken) modes creating bimodal CCN distributions (Hudson et al., 2015). Various measurements made during the MArine Stratus/stratocumulus Experiment (MASE), including CCN, exhibited aqueous processing signals. Particle size distributions; measured by a differential mobility analyzer; were compared with CCN distributions; measured by the Desert Research Institute CCN spectrometer; by converting size to Sc using κ to overlay concurrent distributions. By tuning each mode to the best agreement, κ for each mode is determined; processed κ (κp), unprocessed κ (κu). In MASE, 59% of bimodal distributions had different κ for the two modes indicating dominance of chemical processing via aqueous oxidation. This is consistent with Hudson et al. (2015). Figure 1A also indicates chemical processing with larger κp between 0.35-0.75. Processed CCN had an influx of soluble material from aqueous oxidation which increased κp versus κu. Above 0.75 κp is lower than κu (Fig. 1A). When κu is high and sulfate material is added, κp tends towards κ of the added material. Thus, κp is reduced by additional material that is less soluble than the original material. Chemistry measurements in MASE also indicate in-cloud aqueous oxidation (Fig. 1B and 1C). Higher fraction of CCN concentrations in the processed mode are also associated with larger amounts of sulfates (Fig. 1B, red) and nitrates (Fig. 1C, orange) while SO2 (Fig. 1B, black) and O3 (Fig. 1C, blue) have lower amounts. This larger amount of sulfate is at the expense of SO2, indicating aqueous oxidation within cloud as associated with larger concentrations in the processed mode. Thus, in situ measurements indicate that chemical cloud processing alters size, Sc and κ of activated CCN. Hudson et al. (2015), JGRA, 120, 3436-3452.

Non-destructive characterization of corroded glass surfaces by spectroscopic ellipsometry

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

Kaspar, Tiffany C.; Reiser, Joelle T.; Ryan, Joseph V.

Characterization of the alteration layers that form on glass surfaces during corrosion processes provides valuable information on both the mechanisms and rate of glass alteration. In recent years, state-of-the-art materials and surface characterization techniques have been employed to study various aspects of the alteration layers that result from corrosion. In most cases, these techniques are destructive and thus can only be employed at the end of the corrosion experiment. We show that the alteration layers can be investigated by non-destructive spectroscopic ellipsometry (SE), which provides pertinent information on alteration layer thickness, morphology, and, through correlation of the index of refraction,more » porosity. SE measurements of silicate glass coupons altered in aqueous solutions of pH 3, 5, 7, 9, and 11 at 90 °C for 7 days are compared to cross-sectional secondary electron microscopy images. In most cases, quantitative agreement of the alteration layer thickness is obtained. The fractional porosity calculated from the index of refraction is lower than the porosity calculated from elemental analysis of the aqueous solutions, indicating that the alteration layer has compacted during corrosion or the subsequent supercritical CO 2 drying process. Our results confirm the utility of performing non-destructive SE measurements on corroded glass surfaces.« less

Non-destructive characterization of corroded glass surfaces by spectroscopic ellipsometry

DOE PAGES

Kaspar, Tiffany C.; Reiser, Joelle T.; Ryan, Joseph V.; ...

2017-11-03

Characterization of the alteration layers that form on glass surfaces during corrosion processes provides valuable information on both the mechanisms and rate of glass alteration. In recent years, state-of-the-art materials and surface characterization techniques have been employed to study various aspects of the alteration layers that result from corrosion. In most cases, these techniques are destructive and thus can only be employed at the end of the corrosion experiment. We show that the alteration layers can be investigated by non-destructive spectroscopic ellipsometry (SE), which provides pertinent information on alteration layer thickness, morphology, and, through correlation of the index of refraction,more » porosity. SE measurements of silicate glass coupons altered in aqueous solutions of pH 3, 5, 7, 9, and 11 at 90 °C for 7 days are compared to cross-sectional secondary electron microscopy images. In most cases, quantitative agreement of the alteration layer thickness is obtained. The fractional porosity calculated from the index of refraction is lower than the porosity calculated from elemental analysis of the aqueous solutions, indicating that the alteration layer has compacted during corrosion or the subsequent supercritical CO 2 drying process. Our results confirm the utility of performing non-destructive SE measurements on corroded glass surfaces.« less

EFFECT OF AQUEOUS PHASE PROPERTIES ON CLAY PARTICLE ZETA POTENTIAL AND ELECTRO-OSMOTIC PERMEABILITY: IMPLICATIONS FOR ELECTRO-KINETIC SOIL REMEDIATION PROCESSES

EPA Science Inventory

The influence of aqueous phase properties (pH, ionic strength and divalent metal ion concentration) on clay particle zeta potential and packed-bed electro-osmotic permeability was quantified. Although pH strongly altered the zeta potential of a Georgia kaolinite, it did not signi...

Coordinated Chemical and Isotopic Imaging of Bells (CM2) Meteorite Matrix

NASA Technical Reports Server (NTRS)

Clemett, S. J.; Messenger, S.; Naklamura-Messenger, K.; Thomas-Keprta, K. L.

2014-01-01

Meteoritic organic matter is a complex conglomeration of species formed in distinct environments and processes in circumstellar space, the interstellar medium, the Solar Nebula and asteroids. Consequently meteorites constitute a unique record of primordial organic chemical evolution. While bulk chemical analysis has provided a detailed description of the range and diversity of organic species present in carbonaceous chondrites, there is little information as to how these species are spatially distributed and their relationship to the host mineral matrix. The distribution of organic phases is nevertheless critical to understanding parent body processes. The CM and CI chondrites all display evidence of low temperature (< 350K) aqueous alteration that may have led to aqueous geochromatographic separation of organics and synthesis of new organics coupled to aqueous mineral alteration. Here we present the results of the first coordinated in situ isotopic and chemical mapping study of the Bells meteorite using a newly developed two-step laser mass spectrometer (mu-L(sup 2)MS) capable of measuring a broad range of organic compounds.

Phyllosilicate absorption features in main-belt and outer-belt asteroid reflectance spectra.

PubMed

Vilas, F; Gaffey, M J

1989-11-10

Absorption features having depths up to 5% are identified in high-quality, high-resolution reflectance spectra of 16 dark asteroids in the main belt and in the Cybele and Hilda groups. Analogs among the CM2 carbonaceous chondrite meteorites exist for some of these asteroids, suggesting that these absorptions are due to iron oxides in phyllosilicates formed on the asteroidal surfaces by aqueous alteration processes. Spectra of ten additional asteroids, located beyond the outer edge of the main belt, show no discernible absorption features, suggesting that aqueous alteration did not always operate at these heliocentric distances.

Phyllosilicate absorption features in main-belt and outer-belt asteroid reflectance spectra

NASA Technical Reports Server (NTRS)

Vilas, Faith; Gaffey, Michael J.

1989-01-01

Absorption features having depths up to 5 percent are identified in high-quality, high-resolution reflectance spectra of 16 dark asteroids in the main belt and in the Cybele and Hilda groups. Analogs among the CM2 carbonaceous chondrite meteorites exist for some of these asteroids, suggesting that these absorptions are due to iron oxides in phyllosilicates formed on the asteroidal surfaces by aqueous alteration processes. Spectra of ten additional asteroids, located beyond the outer edge of the main belt, show no discernible absorption features, suggesting that aqueous alteration did not always operate at these heliocentric distances.

Dark inclusions in CO3 chondrites: new indicators of parent-body processes

NASA Astrophysics Data System (ADS)

Itoh, Daisuke; Tomeoka, Kazushige

2003-01-01

A petrographic and scanning electron microscopic study of the four CO3 chondrites Kainsaz, Ornans, Lancé, and Warrenton reveals for the first time that dark inclusions (DIs) occur in all the meteorites. DIs are mostly smaller in size than those reported from CV3 chondrites. They show evidence suggesting that they were formed by aqueous alteration and subsequent dehydration of a chondritic precursor and so probably have a formation history similar to that of DIs in CV3 chondrites. DIs in the CO3 chondrites consist mostly of fine-grained, Fe-rich olivine and can be divided into two types on the basis of texture. Type I DIs contain rounded, porous aggregates of fine grains in a fine-grained matrix and have textures suggesting that they are fragments of chondrule pseudomorphs. Veins filled with Fe-rich olivine are common in type I DIs, providing evidence that they experienced aqueous alteration on the parent body. Type II DIs lack rounded porous aggregates and have a matrix-like, featureless texture. Bulk chemical compositions of DIs and mineralogical characteristics of olivine grains in DIs suggest that these two types of DIs have a close genetic relationship. The DIs are probably clasts that have undergone aqueous alteration and subsequent dehydration at a location different from the present location in the meteorites. The major element compositions, the mineralogy of metallic phases, and the widely dispersed nature of the DIs suggest that their precursor was CO chondrite material. The CO parent body has been commonly regarded to have been dry, homogeneous, and unprocessed. However, the DIs suggest that the CO parent body was a heterogeneous conglomerate consisting of water-bearing regions and water-free regions and that during asteroidal heating, the water-bearing regions were aqueously altered and subsequently dehydrated. Brecciation may also have been active in the parent body. The DIs and the matrices are similarly affected by thermal metamorphism in their own host CO3 chondrites (petrologic subtypes 3.1 to 3.6), but the degree of the secondary processing (aqueous alteration and subsequent dehydration) of the DIs has no apparent correlation with the petrologic grades of the host chondrites. These observations suggest that the DIs had been incorporated into the host chondrites before the thermal metamorphism took place and that the secondary processes that affected the DIs largely occurred before the thermal metamorphism.

Textural constraints on the formation of alteration phases in CM chondrites

NASA Technical Reports Server (NTRS)

Joseph, L. H.; Browning, L. B.; Zolensky, M. E.

1994-01-01

Although it is generally believed that the secondary alteration phases observed in CM chondrites resulted from parent body reactions, the influence of nebular processing can not yet be dismissed. We have analyzed 5 CM falls using optical and electron microscopy to construct a comprehensive pictorial reference set of textural and mineralogical associations bearing on the origin of alteration products in these meteorites. Our analyses support pervasive aqueous alteration on the CM parent body, but they do not exclude the possibility of minor nebular alteration.

CI chondrite-like clasts in the Nilpena polymict ureilite - Implications for aqueous alteration processes in CI chondrites

NASA Technical Reports Server (NTRS)

Brearley, Adrian J.; Prinz, Martin

1992-01-01

Petrographic studies of Nilpena polymict ureilite have revealed the presence of small quantities of carbonaceous chondrite matrix clasts. Detailed electron microprobe and TEM studies show that the chemistry and fine-scale mineralogy of one of these clasts is consistent with CI carbonaceous chondrite matrix. Compared to Orgeuil, the phyllosilicate, sulfide, and oxide mineralogy suggests that the Nilpena clasts may represent a less altered type of CI matrix. It is suggested that increased oxidation and aqueous alteration of Nilpena-type materials could result in the formation of the type of mineral assemblage observed in Orgueil. Increased alteration produces progressive more Mg-rich phyllosilicates and more Fe(3+)-rich iron oxides, such as ferrihydrite. As a function of increased alteration, Ca is also progressively leached from the matrix material to form carbonate veins. The depletion of Ca in CI chondrite matrices suggests the Ivuna and Alais may be intermediate in their degree of alteration to Nilpena and Orgueil.

Evolution of organic matter in Orgueil, Murchison and Renazzo during parent body aqueous alteration: In situ investigations

NASA Astrophysics Data System (ADS)

Le Guillou, Corentin; Bernard, Sylvain; Brearley, Adrian J.; Remusat, Laurent

2014-04-01

Chondrites accreted the oldest solid materials in the solar system including dust processed in the protoplanetary disk and diverse organic compounds. After accretion, asteroidal alteration may have impacted organic particles in various ways. To constrain these processes, we conducted a comprehensive study of organics disseminated within the matrices of the three carbonaceous chondrite falls, Renazzo (CR2), Murchison (CM2) and Orgueil (CI). By combining synchrotron-based STXM and TEM analyses on FIB sections of samples previously characterized by NanoSIMS, we investigated the influence of aqueous alteration on the morphology, isotopic signature, molecular structure, spatial distribution, and mineralogical environment of the organic matter within the matrices. Two different populations of materials are distinguishable: sub-micrometric individual grains, likely dominated by insoluble compounds and diffuse organic matter, finely interspersed within phyllosilicates and/or (amorphous) nanocarbonates at the nanometer scale. We suggest that this latter component, which is depleted in aromatics and enriched in carboxylic functional groups, may be dominated by soluble compounds. Organic matter in Renazzo (CR) mainly consists of chemically-homogeneous individual grains surrounded by amorphous and nanocrystalline phyllosilicates. Evidence of connectivity between organic grains and fractures indicates that redistribution has occurred: some areas containing diffuse organic matter can be observed. This diffuse organic component is more abundant in Murchison (CM) and Orgueil (CI). This is interpreted as resulting from fluid transport at the micrometer scale and encapsulation within recrystallized alteration phases. In contrast to Renazzo, organic grains in Murchison and Orgueil display strong chemical heterogeneities, likely related to chemical evolution during aqueous alteration. The observations suggest that the altering fluid was a brine with elevated concentrations of both organic and inorganic soluble components. Ultimately, when water was consumed by aqueous alteration reactions or lost from the system, soluble organic compounds accumulated in the immediate vicinity of the precipitated carbonates and phosphates. Additionally, the nanometer scale organic/phyllosilicate relationships provide a petrological environment where some of the initially accreted organic matter could have been modified through clay-mediated reactions.

Short Range-Ordered Minerals: Insight into Aqueous Alteration Processes on Mars

NASA Technical Reports Server (NTRS)

Ming, Douglas W.; Morris, R. V.; Golden, D. C.

2011-01-01

Short range-ordered (SRO) aluminosilicates (e.g., allophane) and nanophase ferric oxides (npOx) are common SRO minerals derived during aqueous alteration of basaltic materials. NpOx refers to poorly crystalline or amorphous alteration products that can be any combination of superparamagnetic hematite and/or goethite, akaganeite, schwertmannite, ferrihydrite, iddingsite, and nanometer-sized ferric oxide particles that pigment palagonitic tephra. Nearly 30 years ago, SRO phases were suggested as alteration phases on Mars based on similar spectral properties for altered basaltic tephra on the slopes of Mauna Kea in Hawaii and Martian bright regions measured by Earth-based telescopes. Detailed characterization of altered basaltic tephra on Mauna Kea have identified a variety of alteration phases including allophane, npOx, hisingerite, jarosite, alunite, hematite, goethite, ferrihydrite, halloysite, kaolinite, smectite, and zeolites. The presence of npOx and other Fe-bearing minerals (jarosite, hematite, goethite) was confirmed by the M ssbauer Spectrometer onboard the Mars Exploration Rovers. Although the presence of allophane has not been definitely identified on Mars robotic missions, chemical analysis by the Spirit and Opportunity rovers and thermal infrared spectral orbital measurements suggest the presence of allophane or allophane-like phases on Mars. SRO phases form under a variety of environmental conditions on Earth ranging from cold and arid to warm and humid, including hydrothermal conditions. The formation of SRO aluminosilicates such as allophane (and crystalline halloysite) from basaltic material is controlled by several key factors including activity of water, extent of leaching, Si activity in solution, and available Al. Generally, a low leaching index (e.g., wet-dry cycles) and slightly acidic to alkaline conditions are necessary. NpOx generally form under aqueous oxidative weathering conditions, although thermal oxidative alteration may occasional be involved. The style of aqueous alteration (hydrolytic vs. acid sulfate) impacts which phases will form (e.g., oxides, oxysulfates, and oxyhydroxides). Knowledge on the formation processes of SRO phases in basaltic materials on Earth has allowed significant enhancement in our understanding of the aqueous processes at work on Mars. The 2011 Mars Science Laboratory (MSL) will provide an instrument suite that should improve our understanding of the mineralogical and chemical compositions of SRO phases. CheMin is an X-ray diffraction instrument that may provide broad X-ray diffraction peaks for SRO phases; e.g., broad peaks around 0.33 and 0.23 nm for allophane. Sample Analysis at Mars (SAM) heats samples and detects evolved gases of volatile-bearing phases including SRO phases (i.e., carbonates, sulfates, hydrated minerals). The Alpha Particle X-ray Spectrometer (APXS) and ChemCam element analyzers will provide chemical characterization of samples. The identification of SRO phases in surface materials on MSL will be challenging due to their nanocrystalline properties; their detection and identification will require utilizing the MSL instrument suite in concert. Ultimately, sample return missions will be required to definitively identify and fully characterize SRO minerals with state-of-the-art laboratory instrumentation back on Earth.

Evidence for Extended Aqueous Alteration in CR Carbonaceous Chondrites

NASA Technical Reports Server (NTRS)

Trigo-Rodriquez, J. M.; Moyano-Cambero, C. E.; Mestres, N.; Fraxedas, J.; Zolensky, M.; Nakamura, T.; Martins, Z.

2013-01-01

We are currently studying the chemical interrelationships between the main rockforming components of carbonaceous chondrites (hereafter CC), e.g. silicate chondrules, refractory inclusions and metal grains, and the surrounding meteorite matrices. It is thought that the fine-grained materials that form CC matrices are representing samples of relatively unprocessed protoplanetary disk materials [1-3]. In fact, modern non-destructive analytical techniques have shown that CC matrices host a large diversity of stellar grains from many distinguishable stellar sources [4]. Aqueous alteration has played a role in homogeneizing the isotopic content that allows the identification of presolar grains [5]. On the other hand, detailed analytical techniques have found that the aqueously-altered CR, CM and CI chondrite groups contain matrices in which the organic matter has experienced significant processing concomitant to the formation of clays and other minerals. In this sense, clays have been found to be directly associated with complex organics [6, 7]. CR chondrites are particularly relevant in this context as this chondrite group contains abundant metal grains in the interstitial matrix, and inside glassy silicate chondrules. It is important because CR are known for exhibiting a large complexity of organic compounds [8-10], and only metallic Fe is considered essential in Fischer-Tropsch catalysis of organics [11-13]. Therefore, CR chondrites can be considered primitive materials capable to provide clues on the role played by aqueous alteration in the chemical evolution of their parent asteroids.

Aqueous Alteration on Mars. Chapter 23

NASA Technical Reports Server (NTRS)

Ming, Douglas W.; Morris, Richard V.; Clark, Benton C.

2007-01-01

Aqueous alteration is the change in composition of a rock, produced in response to interactions with H2O-bearing ices, liquids, and vapors by chemical weathering. A variety of mineralogical and geochemical indicators for aqueous alteration on Mars have been identified by a combination of surface and orbital robotic missions, telescopic observations, characterization of Martian meteorites, and laboratory and terrestrial analog studies. Mineralogical indicators for aqueous alteration include goethite (lander), jarosite (lander), kieserite (orbiter), gypsum (orbiter) and other Fe-, Mg-, and Ca-sulfates (landers), halides (meteorites, lander), phyllosilicates (orbiter, meteorites), hematite and nanophase iron oxides (telescopic, orbiter, lander), and Fe-, Mg-, and Ca-carbonates (meteorites). Geochemical indicators (landers only) for aqueous alteration include Mg-, Ca-, and Fe-sulfates, halides, and secondary aluminosilicates such as smectite. Based upon these indicators, several styles of aqueous alteration have been suggested on Mars. Acid-sulfate weathering (e.g., formation of jarosite, gypsum, hematite, and goethite), may occur during (1) the oxidative weathering of ultramafic igneous rocks containing sulfides, (2) sulfuric acid weathering of basaltic materials, and (3) acid fog (i.e., vapors rich in H2SO4) weathering of basaltic or basaltic-derived materials. Near-neutral or alkaline alteration occurs when solutions with pH near or above 7 move through basaltic materials and form phases such as phyllosilicates and carbonates. Very low water:rock ratios appear to have been prominent at most of the sites visited by landed missions because there is very little alteration (leaching) of the original basaltic composition (i.e., the alteration is isochemical or in a closed hydrologic system). Most of the aqueous alteration appears to have occurred early in the history of the planet (3 to 4.5 billion years ago); however, minor aqueous alteration may be occurring at the surface even today (e.g., in thin films of water or by acid fog).

Ca-Fe and Alkali-Halide Alteration of an Allende Type B CAI: Aqueous Alteration in Nebular or Asteroidal Settings

NASA Technical Reports Server (NTRS)

Ross, D. K.; Simon, J. I.; Simon, S. B.; Grossman, L.

2012-01-01

Ca-Fe and alkali-halide alteration of CAIs is often attributed to aqueous alteration by fluids circulating on asteroidal parent bodies after the various chondritic components have been assembled, although debate continues about the roles of asteroidal vs. nebular modification processes [1-7]. Here we report de-tailed observations of alteration products in a large Type B2 CAI, TS4 from Allende, one of the oxidized subgroup of CV3s, and propose a speculative model for aqueous alteration of CAIs in a nebular setting. Ca-Fe alteration in this CAI consists predominantly of end-member hedenbergite, end-member andradite, and compositionally variable, magnesian high-Ca pyroxene. These phases are strongly concentrated in an unusual "nodule" enclosed within the interior of the CAI (Fig. 1). The Ca, Fe-rich nodule superficially resembles a clast that pre-dated and was engulfed by the CAI, but closer inspection shows that relic spinel grains are enclosed in the nodule, and corroded CAI primary phases interfinger with the Fe-rich phases at the nodule s margins. This CAI also contains abundant sodalite and nepheline (alkali-halide) alteration that occurs around the rims of the CAI, but also penetrates more deeply into the CAI. The two types of alteration (Ca-Fe and alkali-halide) are adjacent, and very fine-grained Fe-rich phases are associated with sodalite-rich regions. Both types of alteration appear to be replacive; if that is true, it would require substantial introduction of Fe, and transport of elements (Ti, Al and Mg) out of the nodule, and introduction of Na and Cl into alkali-halide rich zones. Parts of the CAI have been extensively metasomatized.

Fe-Ni metal and sulfide minerals in CM chondrites: An indicator for thermal history

USGS Publications Warehouse

Kimura, M.; Grossman, J.N.; Weisberg, M.K.

2011-01-01

CM chondrites were subjected to aqueous alteration and, in some cases, to secondary metamorphic heating. The effects of these processes vary widely, and have mainly been documented in silicate phases. Herein, we report the characteristic features of Fe-Ni metal and sulfide phases in 13 CM and 2 CM-related chondrites to explore the thermal history of these chondrites. The texture and compositional distribution of the metal in CM are different from those in unequilibrated ordinary and CO chondrites, but most have similarities to those in highly primitive chondrites, such as CH, CR, and Acfer 094. We classified the CM samples into three categories based on metal composition and sulfide texture. Fe-Ni metal in category A is kamacite to martensite. Category B is characterized by pyrrhotite grains always containing blebs or lamellae of pentlandite. Opaque mineral assemblages of category C are typically kamacite, Ni-Co-rich metal, and pyrrhotite. These categories are closely related to the degree of secondary heating and are not related to degree of the aqueous alteration. The characteristic features of the opaque minerals can be explained by secondary heating processes after aqueous alteration. Category A CM chondrites are unheated, whereas those in category B experienced small degrees of secondary heating. CMs in category C were subjected to the most severe secondary heating process. Thus, opaque minerals can provide constraints on the thermal history for CM chondrites. ?? The Meteoritical Society, 2011.

Mutnovsky and Gorely Volcanoes, Kamchatka as Planetary Analogue Sites

NASA Astrophysics Data System (ADS)

Evdokimova, N.; Izbekov, P. E.; Krupskaya, V.; Muratov, A.

2016-12-01

Recent advances in Mars studies suggest that volcanic rocks, which dominated Martian surface in the past, have been exposed to alteration processes in a water-bearing environment during Noachian, before 3.7 Gy. Active volcanoes on Earth are natural laboratories, where volcanic processes and their associated products can be studied directly. This is particularly important for studying of alteration of juvenile volcanic products in aqueous environment because of the transient nature of some of the alteration products, as well as the environment itself. Terrestrial analogues help us to better understand processes on Mars; they are particularly useful as a test sites for preparation to future Mars missions. In this presentation we describe planetary analogue sites at Mutnovsky and Gorely Volcanoes in Kamchatka, which might be helpful for comparative studies and preparation to future Mars missions. Mutnovsky and Gorely Volcanoes are located 75 km south of Petropavlovsk-Kamchatsky, in the southern part of the Kamchatka Peninsula, Russia. The modern volcanic landscape in the area was shaped in Holocene (recent 10,000 years) through intermittent eruption of magmas ranging in composition from basalts to dacites and rhyodacites, with basaltic andesite lavas dominating in the modern relief. Two localities could be of a particular interest: (1) Mutnovsky NW thermal field featuring processes of active hydrothermal alteration of lavas of basaltic andesite and (2) dry lake at the bottom of Gorely caldera featuring products of mechanical disintegration of basaltic andesite lavas by eolian processes with short seasonal sedimentation in aqueous environment.

Aqueous Alteration of Carbonaceous Chondrites: New Insights from Comparative Studies of Two Unbrecciated CM2 Chondrites, Y 791198 and ALH 81002

NASA Technical Reports Server (NTRS)

Chizmadia, L. J.; Brearley, A. J.

2004-01-01

Carbonaceous chondrites are an important resource for understanding the physical and chemical conditions in the early solar system. In particular, a long-standing question concerns the role of water in the cosmochemical evolution of carbonaceous chondrites. It is well established that extensive hydration of primary nebular phases occurred in the CM and CI chondrites, but the location where this alteration occurred remains controversial. In the CM2 chondrites, hydration formed secondary phases such as serpentine, tochilinite, pentlandite, carbonate and PCP. There are several textural observations which suggest that alteration occurred before the accretion of the final CM parent asteroid, i.e. preaccretionary alteration. Conversely, there is a significant body of evidence that supports parent-body alteration. In order to test these two competing hypotheses further, we studied two CM chondrites, Y-791198 and ALH81002, two meteorites that exhibit widely differing degrees of aqueous alteration. In addition, both meteorites have primary accretionary textures, i.e. experienced minimal asteroidal brecciation. Brecciation significantly complicates the task of unraveling alteration histories, mixing components that have been altered to different degrees from different locations on the same asteroidal parent body. Alteration in Y-791198 is mostly confined to chondrule mesostases, FeNi metal and fine-grained matrix and rims. In comparison, the primary chondrule silicates in ALH81002 have undergone extensive replacement by secondary hydrous phases. This study focuses on compositional and textural relationships between chondrule mesostasis and the associated rim materials. Our hypothesis is: both these components are highly susceptible to aqueous alteration and should be sensitive recorders of the alteration process. For parent body alteration, we expect systematic coupled mineralogical and compositional changes in rims and altered mesostasis, as elemental exchange between these components occurs. Conversely, for preaccretionary alteration, there should be no clear relationships between the rims and mesostases.

Primitive Liquid Water of the Solar System in an Aqueous Altered Carbonaceous Chondrite

NASA Technical Reports Server (NTRS)

Tsuchiyama, A.; Miyake, A.; Kitayama, A.; Matsuno, J.; Takeuchi, A.; Uesugi, K.; Suzuki, Y.; Nakano, T.; Zolensky, M. E.

2016-01-01

Non-destructive 3D observations of the aqueous altered CM chondrite Sutter's Mill using scanning imaging x-ray microscopy (SIXM) showed that some of calcite and enstatite grains contain two-phase inclusion, which is most probably composed of liquid water and bubbles. This water should be primitive water responsible for aqueous alteration in an asteroid in the early solar system.

Thermal Studies of Ammonium Cyanide Reactions: A Model for Thermal Alteration of Prebiotic Compounds in Meteorite Parent Bodies

NASA Technical Reports Server (NTRS)

Hammer, P. G.; Locke, D. R.; Burton, A. S.; Callahan, M. P.

2017-01-01

Organic compounds in carbonaceous chondrites were likely transformed by a variety of parent body processes including thermal and aqueous processing. Here, we analyzed ammonium cyanide reactions that were heated at different temperatures and times by multiple analytical techniques. The goal of this study is to better understand the effect of hydrothermal alteration on cyanide chemistry, which is believed to be responsible for the abiotic synthesis of purine nucleobases and their structural analogs detected in carbonaceous chondrites.

The effects of parent body processes on amino acids in carbonaceous chondrites

NASA Astrophysics Data System (ADS)

Glavin, Daniel P.; Callahan, Michael P.; Dworkin, Jason P.; Elsila, Jamie E.

2010-12-01

To investigate the effect of parent body processes on the abundance, distribution, and enantiomeric composition of amino acids in carbonaceous chondrites, the water extracts from nine different powdered CI, CM, and CR carbonaceous chondrites were analyzed for amino acids by ultra performance liquid chromatography-fluorescence detection and time-of-flight mass spectrometry (UPLC-FD/ToF-MS). Four aqueously altered type 1 carbonaceous chondrites including Orgueil (CI1), Meteorite Hills (MET) 01070 (CM1), Scott Glacier (SCO) 06043 (CM1), and Grosvenor Mountains (GRO) 95577 (CR1) were analyzed using this technique for the first time. Analyses of these meteorites revealed low levels of two- to five-carbon acyclic amino alkanoic acids with concentrations ranging from approximately 1 to 2,700 parts-per-billion (ppb). The type 1 carbonaceous chondrites have a distinct distribution of the five-carbon (C5) amino acids with much higher relative abundances of the γ- and δ-amino acids compared to the type 2 and type 3 carbonaceous chondrites, which are dominated by α-amino acids. Much higher amino acid abundances were found in the CM2 chondrites Murchison, Lonewolf Nunataks (LON) 94102, and Lewis Cliffs (LEW) 90500, the CR2 Elephant Moraine (EET) 92042, and the CR3 Queen Alexandra Range (QUE) 99177. For example, α-aminoisobutyric acid (α-AIB) and isovaline were approximately 100 to 1000 times more abundant in the type 2 and 3 chondrites compared to the more aqueously altered type 1 chondrites. Most of the chiral amino acids identified in these meteorites were racemic, indicating an extraterrestrial abiotic origin. However, nonracemic isovaline was observed in the aqueously altered carbonaceous chondrites Murchison, Orgueil, SCO 06043, and GRO 95577 with L-isovaline excesses ranging from approximately 11 to 19%, whereas the most pristine, unaltered carbonaceous chondrites analyzed in this study had no detectable L-isovaline excesses. These results are consistent with the theory that aqueous alteration played an important role in amplification of small initial left handed isovaline excesses on the parent bodies.

The Effects of Parent Body Processes on Amino Acids in Carbonaceous Chondrites

NASA Technical Reports Server (NTRS)

Glavin, Daniel P.; Callahan, Michael P.; Dworkin, Jason P.; Elsila, Jamie E.

2010-01-01

To investigate the effect of parent body processes on the abundance, distribution, and enantiomeric composition of amino acids in carbonaceous chondrites, the water extracts from nine different powdered Cl, CM, and CR carbonaceous chondrites were analyzed for amino acids by ultrahigh performance liquid chromatography-fluorescence detection and time-of-flight mass spectrometry (UPLC-FD/ToF-MS). Four aqueously altered type 1 carbonaceous chondrites including Orgueil (C11), Meteorite Hills (MET) 01070 (CM1), Scott Glacier (SCO) 06043 (CM1), and Grosvenor Mountains (GRO) 95577 (CR1) were analyzed using this technique for the first time. Analyses of these meteorites revealed low levels of two- to five-carbon acyclic amino alkanoic acids with concentrations ranging from -1 to 2,700 parts-per-billion (ppb). The type 1 carbonaceous chondrites have a distinct distribution of the five-carbon (C5) amino acids with much higher relative abundances of the gamma- and delta-amino acids compared to the type 2 and type 3 carbonaceous chondrites, which are dominated by a-amino acids. Much higher amino acid abundances were found in the CM2 chondrites Murchison, Lonewolf Nunataks (LON) 94102, and Lewis Cliffs (LEW) 90500, the CR2 Elephant Moraine (EET) 92042, and the CR3 Queen Alexandra Range (QUE) 99177. For example, a-aminoisobutyric acid ((alpha-AIB) and isovaline were approximately 100 to 1000 times more abundant in the type 2 and 3 chondrites compared to the more aqueously altered type 1 chondrites. Most of the chiral amino acids identified in these meteorites were racemic, indicating an extraterrestrial abiotic origin. However, non-racemic isovaline was observed in the aqueously altered carbonaceous chondrites Murchison, Orgueil, SCO 06043, and GRO 95577 with L-isovaline excesses ranging from approximately 11 to 19%, whereas the most pristine, unaltered carbonaceous chondrites analyzed in this study had no detectable L-isovaline excesses. These results are consistent with the theory that aqueous alteration played an important role in amplification of small initial left handed isovaline excesses on the parent bodies.

Precipitation of Secondary Phases from the Dissolution of Silicate Glasses

NASA Technical Reports Server (NTRS)

Ming, Douglas W.; Golden, D. C.

2004-01-01

Basaltic and anorthositic glasses were subjected to aqueous weathering conditions in the laboratory where the variables were pH, temperature, glass composition, solution composition, and time. Leached layers formed at the surfaces of glasses followed by the precipitation of X-ray amorphous iron and titanium oxides in acidic and neutral solutions at 25 C over time. Glass under oxidative hydrothermal treatments at 150 C yielded a three-layered surface; which included an outer smectite layer, a Fe-Ti oxide layer and an innermost thin leached layer. The introduction of Mg into solutions facilitated the formation of phyllosilicates. Aqueous hydrothermal treatment of anorthositic glasses (high Ca, low Ti) at 200 C readily formed smectite, whereas, the basaltic glasses (high Ti) were more resistant to alteration and smectite was not observed. Alkaline hydrothermal treatment at 2000e produced zeolites and smectites; only smectites formed at 200 C in neutral solutions. These mineralogical changes, although observed under controlled conditions, have direct applications in interpreting planetary (e.g., meteorite parent bodies) and terrestrial aqueous alteration processes.

Chemical, thermal and impact processing of asteroids

NASA Technical Reports Server (NTRS)

Scott, E. R. D.; Taylor, G. J.; Newsom, H. E.; Herbert, F.; Zolensky, M.

1989-01-01

The geological effects of impacts, heating, melting, core formation, and aqueous alteration on asteroids are reviewed. A review of possible heat sources appears to favor an important role for electrical induction heating. The effects of each geologic process acting individually and in combination with others, are considered; it is concluded that there is much evidence for impacts during alteration, metamorphism and melting. These interactions vastly increased the geologic diversity of the asteroid belt. Subsequent impacts of cool asteroids did not reduce this diversity. Instead new rock types were created by mixing, brecciation and minor melting.

Bioactive Fraction of Geopropolis from Melipona scutellaris Decreases Neutrophils Migration in the Inflammatory Process: Involvement of Nitric Oxide Pathway

PubMed Central

Franchin, Marcelo; da Cunha, Marcos Guilherme; Denny, Carina; Napimoga, Marcelo Henrique; Cunha, Thiago Mattar; Bueno-Silva, Bruno; Matias de Alencar, Severino; Ikegaki, Masaharu; Luiz Rosalen, Pedro

2013-01-01

The aim of this study was to evaluate the activity of the ethanolic extract of geopropolis (EEGP) from Melipona scutellaris and its fractions on the modulation of neutrophil migration in the inflammatory process, and the participation of nitric oxide (NO) pathway, as well as to check the chemical profile of the bioactive fraction. EEGP and its aqueous fraction decreased neutrophil migration in the peritoneal cavity and also the interaction of leukocytes (rolling and adhesion) with endothelial cells. The levels of chemokines CXCL1/KC and CXCL2/MIP-2 were not altered after treatment with EEGP and the aqueous fraction. It was found that the injection of NO pathway antagonists abolished the EEGP and the aqueous fraction inhibitory activity on the neutrophil migration. The expression of intercellular adhesion molecule type 1 (ICAM-1) was reduced, and nitrite levels increased after treatment with EEGP and aqueous fraction. In the carrageenan-induced paw edema model, EEGP and the aqueous fraction showed antiedema activity. No pattern of flavonoid and phenolic acid commonly found in propolis samples of Apis mellifera could be detected in the aqueous fraction samples. These data indicate that the aqueous fraction found has promising bioactive substances with anti-inflammatory activity. PMID:23737853

Bioactive Fraction of Geopropolis from Melipona scutellaris Decreases Neutrophils Migration in the Inflammatory Process: Involvement of Nitric Oxide Pathway.

PubMed

Franchin, Marcelo; da Cunha, Marcos Guilherme; Denny, Carina; Napimoga, Marcelo Henrique; Cunha, Thiago Mattar; Bueno-Silva, Bruno; Matias de Alencar, Severino; Ikegaki, Masaharu; Luiz Rosalen, Pedro

2013-01-01

The aim of this study was to evaluate the activity of the ethanolic extract of geopropolis (EEGP) from Melipona scutellaris and its fractions on the modulation of neutrophil migration in the inflammatory process, and the participation of nitric oxide (NO) pathway, as well as to check the chemical profile of the bioactive fraction. EEGP and its aqueous fraction decreased neutrophil migration in the peritoneal cavity and also the interaction of leukocytes (rolling and adhesion) with endothelial cells. The levels of chemokines CXCL1/KC and CXCL2/MIP-2 were not altered after treatment with EEGP and the aqueous fraction. It was found that the injection of NO pathway antagonists abolished the EEGP and the aqueous fraction inhibitory activity on the neutrophil migration. The expression of intercellular adhesion molecule type 1 (ICAM-1) was reduced, and nitrite levels increased after treatment with EEGP and aqueous fraction. In the carrageenan-induced paw edema model, EEGP and the aqueous fraction showed antiedema activity. No pattern of flavonoid and phenolic acid commonly found in propolis samples of Apis mellifera could be detected in the aqueous fraction samples. These data indicate that the aqueous fraction found has promising bioactive substances with anti-inflammatory activity.

Rocks of the Columbia Hills

USGS Publications Warehouse

Squyres, S. W.; Arvidson, R. E.; Blaney, D.L.; Clark, B. C.; Crumpler, L.; Farrand, W. H.; Gorevan, S.; Herkenhoff, K. E.; Hurowitz, J.; Kusack, A.; McSween, H.Y.; Ming, D. W.; Morris, R.V.; Ruff, S.W.; Wang, A.; Yen, A.

2006-01-01

The Mars Exploration Rover Spirit has identified five distinct rock types in the Columbia Hills of Gusev crater. Clovis Class rock is a poorly sorted clastic rock that has undergone substantial aqueous alteration. We interpret it to be aqueously altered ejecta deposits formed by impacts into basaltic materials. Wishstone Class rock is also a poorly sorted clastic rock that has a distinctive chemical composition that is high in Ti and P and low in Cr. Wishstone Class rock may be pyroclastic or impact in origin. Peace Class rock is a sedimentary material composed of ultramafic sand grains cemented by significant quantities of Mg- and Ca-sulfates. Peace Class rock may have formed when water briefly saturated the ultramafic sands and evaporated to allow precipitation of the sulfates. Watchtower Class rocks are similar chemically to Wishstone Class rocks and have undergone widely varying degrees of near-isochemical aqueous alteration. They may also be ejecta deposits, formed by impacts into Wishstone-rich materials and altered by small amounts of water. Backstay Class rocks are basalt/trachybasalt lavas that were emplaced in the Columbia Hills after the other rock classes were, either as impact ejecta or by localized volcanic activity. The geologic record preserved in the rocks of the Columbia Hills reveals a period very early in Martian history in which volcanic materials were widespread, impact was a dominant process, and water was commonly present. Copyright 2006 by the American Geophysical Union.

The Rocks of the Columbia Hills

NASA Technical Reports Server (NTRS)

Squyres, Steven W.; Arvidson, Raymond E.; Blaney, Diana L.; Clark, Benton C.; Crumpler, Larry; Farrand, William H.; Gorevan, Stephen; Herkenhoff, Kenneth; Hurowitz, Joel; Kusack, Alastair;

Ceres' Evolution Before and After Dawn: Where are We Now?

NASA Astrophysics Data System (ADS)

McCord, T. B.; Castillo, J. C.

2016-12-01

Observations of Ceres before Dawn indicated that it contains 25 wt% water, and thermodynamic modeling indicated Ceres probably had experienced the same process of differentiation due to melting of the original ice after accretion as experienced by large icy moons. Consistent with that was a surface of altered mineralogy like clays suggesting aqueous alteration of the original chondritic silicates. Dawn has revealed some concentration of mass toward the center, specific aqueously altered mineralogies, a stiff surface with weaker material beneath, and extrusions and protrusions suggesting recent subsurface activity, including exposures of water ice that must be very recent. This wealth of new information from Dawn enables selection of more specific evolution models that best match the vastly improved Dawn observations. In this new study we propose one possibility is that Ceres accreted as an ice and silicate mixture after short-lived radionuclides in CAIs had significantly decayed, i.e. nearer 5 my after CAIs, and thus differentiated less completely than for hotter models. On the other hand, the presence of heavily aqueously altered mineralogies, including probably salts, suggests extensive mixing of water and silicates, which might normally be associated with more complete differentiation. Geologically recent activity, perhaps even to the present time, seems evident from several young landforms, including protrusions consistent with diapirism and recent exposures of water ice. This suggests recent flexing of the subsurface and rising of less dense interior material, including salts and ice. The presence of ammoniated minerals and what appear to be salt deposits suggest a major lowering of subsurface water ice melting temperature, enhancing the duration of water-silicate contact, and perhaps accelerating the mineralization processes and slowing or halting differentiation of water and silicates. Thus, Ceres is becoming known as the first body outward from the Sun that has had its evolution controlled by water-driven processes. Investigations of its interior and geology enable by Dawn's observations will in turn help to better understand other ice-rich bodies.

Ceres' evolution before and after Dawn: Where are we now?

NASA Astrophysics Data System (ADS)

McCord, Thomas B.; Castillo-Rogez, Julie C.

2016-10-01

Observations of Ceres before Dawn indicated that it contains ~25 wt% water, and thermodynamic modeling indicated Ceres probably had experienced the same process of differentiation due to melting of the original ice after accretion as experienced by large icy moons. Consistent with that was a surface of altered mineralogy like clays suggesting aqueous alteration of the original chondritic silicates. Dawn has revealed some concentration of mass toward the center, specific aqueously altered mineralogies, a stiff surface with weaker material beneath, and extrusions and protrusions suggesting recent subsurface activity, including exposures of water ice that must be very recent. This wealth of new information from Dawn enables selection of more specific evolution models that best match the vastly improved Dawn observations. In this new study we propose one possibility is that Ceres accreted as an ice and silicate mixture after short-lived radionuclides in CAIs had significantly decayed, i.e. nearer 5 my after CAIs, and thus differentiated less completely than for hotter models. On the other hand, the presence of heavily aqueously altered mineralogies, including probably salts, suggests extensive mixing of water and silicates, which might normally be associated with more complete differentiation. Geologically recent activity, perhaps even to the present time, seems evident from several young landforms, including protrusions consistent with diapirism and recent exposures of water ice. This suggests recent flexing of the subsurface and rising of less dense interior material, including salts and ice. The presence of ammoniated minerals and what appear to be salt deposits suggest a major lowering of subsurface water ice melting temperature, enhancing the duration of water-silicate contact, and perhaps accelerating the mineralization processes and slowing or halting differentiation of water and silicates. Thus, Ceres is becoming known as the first body outward from the Sun that has had its evolution controlled by water-driven processes. Investigations of its interior and geology enable by Dawn's observations will in turn help to better understand other ice-rich bodies.

Aqueous alteration in the Kaba CV3 carbonaceous chondrite

NASA Technical Reports Server (NTRS)

Keller, Lindsay P.; Buseck, Peter R.

1990-01-01

Results from TEM and SEM examinations of the Kaba CV3 carbonaceous chondrite are presented, showing that the chondrules and the matrix of Kaba have undergone pervasive low-temperature aqueous alteration, resulting in the formation of Fe-bearing saponite from glass and enstatite in chondrules, and from anhydrous silicates in matrix. The alteration products in Kaba were found to resemble those in other aqueously altered carbonaceous chondrites such as the Mokoia CV3 and in Orgueil CI chondrites and Y-82162 chondrites. However, Kaba lacks the abundant high-Al phyllosilicates, reported for CAIs from Mokoia, and the serpentine and ferrihydrite, found in Orgueil.

Nature of Reduced Carbon in Martian Meteorites

NASA Technical Reports Server (NTRS)

Gibson, Everett K., Jr.; McKay, D. S.; Thomas-Keprta, K. L.; Clemett, S. J.; White, L. M.

2012-01-01

Martian meteorites provide important information on the nature of reduced carbon components present on Mars throughout its history. The first in situ analyses for carbon on the surface of Mars by the Viking landers yielded disappointing results. With the recognition of Martian meteorites on Earth, investigations have shown carbon-bearing phases exist on Mars. Studies have yielded presence of reduced carbon, carbonates and inferred graphitic carbon phases. Samples ranging in age from the first approximately 4 Ga of Mars history [e.g. ALH84001] to nakhlites with a crystallization age of 1.3 Ga [e.g. Nakhla] with aqueous alteration processes occurring 0.5-0.7 Ga after crystallizaton. Shergottites demonstrate formation ages around 165-500 Ma with younger aqueous alterations events. Only a limited number of the Martian meteorites do not show evidence of significance terrestrial alterations. Selected areas within ALH84001, Nakhla, Yamato 000593 and possibly Tissint are suitable for study of their indigenous reduced carbon bearing phases. Nakhla possesses discrete, well-defined carbonaceous phases present within iddingsite alteration zones. Based upon both isotopic measurements and analysis of Nakhla's organic phases the presence of pre-terrestrial organics is now recognized. The reduced carbon-bearing phases appear to have been deposited during preterrestrial aqueous alteration events that produced clays. In addition, the microcrystalline layers of Nakhla's iddingsite have discrete units of salt crystals suggestive of evaporation processes. While we can only speculate on the origin of these unique carbonaceous structures, we note that the significance of such observations is that it may allow us to understand the role of Martian carbon as seen in the Martian meteorites with obvious implications for astrobiology and the pre-biotic evolution of Mars. In any case, our observations strongly suggest that reduced organic carbon exists as micrometer- size, discrete structures on Mars associated with clay and salt minerals. The Mars Science Laboratory s investigators should be aware of reduced organic carbon components within clay-bearing phases.

[Alterations in tears aqueous layer during cytostatics treatment].

PubMed

Wojciechowska, Katarzyna; Wieckowska-Szakiel, Marzena; Rózalska, Barbara; Jurowski, Piotr

2013-01-01

The aim of the study was to evaluate tears secretion, pH and lysozyme activity in tears aqueous layer during chemotherapy in lung, breast and bowel cancer. 36 patients were enrolled to the study. Depending on the type of cancer and type of chemotherapy patients were divided into three groups. Group I (12 patients) diagnosed with non-small-cell lung cancer treated with PE schema (cisplatin, etoposide), Group II (12 patients) with breast cancer treated with FAC schema (fluorouracil, doxorubicin, cyclophosphamide), Group III (12 patients) with bowel cancer treated with FU/LV schema (fluorouracil, leucovorin). In all the patients: Schirmer's I test, pH measurements and lysozyme test were performed. Patients were examined before chemotherapy, after 2nd, 4th, 6th cycle. In group I and II lowering of tears secretion (p < 0.001) was revealed. In group III there was higher tears secretion (p < 0.001). PH was lowered after 2nd chemotherapy course in group I and II. In further treatment pH value were in the same lower level as after the second course. In group III there was higher pH--more alkaline (p < 0.001) after 2nd cycle of treatment and it was on the same level to the end of the examination process. Lowering of lysozyme activity in the tears film in all groups (p < 0.001) was established. The higher alterations of the lysozyme activity were observed in group treated with FAC schema. Cytostatic treatment has major influence on tears aqueous layer causing alterations of tears secretions. PH alterations depending on type of chemotherapy was observed. Lowering of lysozyme activity in tears was observed. All the deteriorations aggravate with duration of chemotherapy. Alterations of tears film parameters during chemotherapy may influence upon eye surface homeostasis and infectious complication. tears aqueous layer, Schirmer's test, lysozyme activity, tears pH.

Multiphase Aqueous Alteration of the Nakhlite Northwest Africa 817

NASA Astrophysics Data System (ADS)

Lee, M. R.; Cohen, B. E.; Mark, D. F.; Boyce, A.

2017-07-01

The nakhlite meteorite Northwest Africa 817 has been aqueously altered on both Mars and Earth, producing clays, carbonates, sulphates and oxides. The challenge is to see through the terrestrial overprint to understand the martian signature.

Reactive transport and mass balance modeling of the Stimson sedimentary formation and altered fracture zones constrain diagenetic conditions at Gale crater, Mars

NASA Astrophysics Data System (ADS)

Hausrath, E. M.; Ming, D. W.; Peretyazhko, T. S.; Rampe, E. B.

2018-06-01

On a planet as cold and dry as present-day Mars, evidence of multiple aqueous episodes offers an intriguing view into very different past environments. Fluvial, lacustrine, and eolian depositional environments are being investigated by the Mars Science Laboratory Curiosity in Gale crater, Mars. Geochemical and mineralogical observations of these sedimentary rocks suggest diagenetic processes affected the sediments. Here, we analyze diagenesis of the Stimson formation eolian parent material, which caused loss of olivine and formation of magnetite. Additional, later alteration in fracture zones resulted in preferential dissolution of pyroxene and precipitation of secondary amorphous silica and Ca sulfate. The ability to compare the unaltered parent material with the reacted material allows constraints to be placed on the characteristics of the altering solutions. In this work we use a combination of a mass balance approach calculating the fraction of a mobile element lost or gained, τ, with fundamental geochemical kinetics and thermodynamics in the reactive transport code CrunchFlow to examine the characteristics of multiple stages of aqueous alteration at Gale crater, Mars. Our model results indicate that early diagenesis of the Stimson sedimentary formation is consistent with leaching of an eolian deposit by a near-neutral solution, and that formation of the altered fracture zones is consistent with a very acidic, high sulfate solution containing Ca, P and Si. These results indicate a range of past aqueous conditions occurring at Gale crater, Mars, with important implications for past martian climate and environments.

Impact-Induced Chondrule Deformation and Aqueous Alteration of CM2 Murchison

NASA Technical Reports Server (NTRS)

Hanna, R. D.; Zolensky, M.; Ketcham, R. A.; Behr, W. M.; Martinez, J. E.

2014-01-01

Deformed chondrules in CM2 Murchison have been found to define a prominent foliation [1,2] and lineation [3] in 3D using X-ray computed tomography (XCT). It has been hypothesized that chondrules in foliated chondrites deform by "squeezing" into surrounding pore space [4,5], a process that also likely removes primary porosity [6]. However, shock stage classification based on olivine extinction in Murchison is consistently low (S1-S2) [4-5,7] implying that significant intracrystalline plastic deformation of olivine has not occurred. One objective of our study is therefore to determine the microstructural mechanisms and phases that are accommodating the impact stress and resulting in relative displacements within the chondrules. Another question regarding impact deformation in Murchison is whether it facilitated aqueous alteration as has been proposed for the CMs which generally show a positive correlation between degree of alteration and petrofabric strength [7,2]. As pointed out by [2], CM Murchison represents a unique counterpoint to this correlation: it has a strong petrofabric but a relatively low degree of aqueous alteration. However, Murchison may not represent an inconsistency to the proposed causal relationship between impact and alteration, if it can be established that the incipient aqueous alteration post-dated chondrule deformation. Methods: Two thin sections from Murchison sample USNM 5487 were cut approximately perpendicular to the foliation and parallel to lineation determined by XCT [1,3] and one section was additionally polished for EBSD. Using a combination of optical petrography, SEM, EDS, and EBSD several chondrules were characterized in detail to: determine phases, find microstructures indicative of strain, document the geometric relationships between grain-scale microstructures and the foliation and lineation direction, and look for textural relationships of alteration minerals (tochilinite and Mg-Fe serpentine) that indicate timing of their formation relative to deformation event(s). Preliminary Results: Deformed chondrules are dominated by forsterite and clinoenstatite with lesser amounts of Fe-Mg serpentine, sulfides, and low calcium pyroxene. Olivine grains are commonly fractured but generally show sharp optical extinction. The pyroxene, in contrast, is not only fractured but also often displays undulose extinction. In addition, the clinoenstatite is frequently twinned but it is unclear whether the twins are the result of mechanical deformation or inversion from protoenstatite [8]. EBSD work is currently ongoing to determine if areas of higher crystallographic strain can be imaged and mapped, and to determine the pyroxene twin orientations. In regards to alteration, we have found evidence for post-deformation formation of tochilinite and Mg-Fe serpentine indicating that aqueous alteration has indeed post-dated the deformation of the chondrules.

Aqueous fluid composition in CI chondritic materials: Chemical equilibrium assessments in closed systems

NASA Astrophysics Data System (ADS)

Zolotov, Mikhail Yu.

2012-08-01

Solids of nearly solar composition have interacted with aqueous fluids on carbonaceous asteroids, icy moons, and trans-neptunian objects. These processes altered mineralogy of accreted materials together with compositions of aqueous and gaseous phases. We evaluated chemistry of aqueous solutions coexisted with CI-type chondritic solids through calculations of chemical equilibria in closed water-rock-gas systems at different compositions of initial fluids, water/rock mass ratios (0.1-1000), temperatures (<350 °C), and pressures (<2 kbars). The calculations show that fluid compositions are mainly affected by solubilities of solids, the speciation of chlorine in initial water-rock mixtures, and the occurrence of Na-bearing secondary minerals such as saponite. The major species in modeled alkaline solutions are Na+, Cl-, CO32-,HCO3-, K+, OH-, H2, and CO2. Aqueous species of Mg, Fe, Ca, Mn, Al, Ni, Cr, S, and P are not abundant in these fluids owing to low solubility of corresponding solids. Typical NaCl type alkaline fluids coexist with saponite-bearing mineralogy that usually present in aqueously altered chondrites. A common occurrence of these fluids is consistent with the composition of grains emitted from Enceladus. Na-rich fluids with abundant CO32-,HCO3-, and OH- anions coexist with secondary mineralogy depleted in Na. The Na2CO3 and NaHCO3 type fluids could form via accretion of cometary ices. NaOH type fluids form in reduced environments and may locally occur on parent bodies of CR carbonaceous chondrites. Supposed melting of accreted HCl-bearing ices leads to early acidic fluids enriched in Mg, Fe and other metals, consistent with signs of low-pH alteration in chondrites. Neutralization of these solutions leads to alkaline Na-rich fluids. Sulfate species have negligible concentrations in closed systems, which remain reduced, especially at elevated pressures created by forming H2 gas. Hydrogen, CO2, and H2O dominate in the gaseous phase, though the abundance of methane cannot be fairly estimated.

On the Behavior of Phosphorus During the Aqueous Alteration of CM2 Carbonaceous Chondrites

NASA Technical Reports Server (NTRS)

Brearley, Adrian J.; Chizmadia, Lysa J.

2005-01-01

During the earliest period of solar system formation, water played an important role in the evolution of primitive dust, both after accretion of planetesimals and possible before accretion within the protoplanetary disk. Many chondrites show evidence of variable degrees of aqueous alteration, the CM2 chondrites being among the most studied [1]. This group of chondrites is characterized by mineral assemblages of both primary and secondary alteration phases. Hence, these meteorites retain a particularly important record of the reactions that occurred between primary high temperature nebular phases and water. Studies of these chondrites can provide information on the conditions and environments of aqueous alteration and the mobility of elements during alteration. This latter question is at the core of a debate concerning the location of aqueous alteration, i.e. whether alteration occurred predominantly within a closed system after accretion (parent body alteration) or whether some degree of alteration occurred within the solar nebula or on ephemeral protoplanetary bodies prior to accretion. At the core of the parent body alteration model is the hypothesis that elemental exchange between different components, principally chondrules and matrix, must have occurred. chondrules and matrix, must have occurred. In this study, we focus on the behavior of the minor element, phosphorus. This study was stimulated by observations of the behavior of P during the earliest stages of alteration in glassy mesostasis in type II chondrules in CR chondrites and extends the preliminary observations of on Y791198 to other CM chondrites.

Lithium isotopes as indicators of meteorite parent body alteration

NASA Astrophysics Data System (ADS)

Sephton, Mark A.; James, Rachael H.; Fehr, Manuela A.; Bland, Philip A.; Gounelle, Matthieu

2013-05-01

Hydrothermal processing on planetesimals in the early solar system produced new mineral phases, including those generated by the transformation of anhydrous silicates into their hydrated counterparts. Carbonaceous chondrites represent tangible remnants of such alteration products. Lithium isotopes are known to be responsive to aqueous alteration, yet previously recognized variability within whole rock samples from the same meteorite appears to complicate the use of these isotopes as indicators of processing by water. We demonstrate a new way to use lithium isotopes that reflects aqueous alteration in carbonaceous chondrites. Temperature appears to exert a control on the production of acetic acid-soluble phases, such as carbonates and poorly crystalline Fe-oxyhydroxides. Temperature and degree of water-rock interaction determines the amount of lithium isotope fractionation expressed as the difference between whole rock and acetic acid-leachable fractions. Using these features, the type 1 chondrite Orgueil (δ7Li(whole rock) = 4.3‰; Δ7Li(acetic-whole) = 1.2‰) can be distinguished from the type 2 chondrites Murchison (δ7Li(whole rock) = 3.8; Δ7Li(acetic-whole) = 8.8‰) and carbonate-poor Tagish Lake (δ7Li(whole rock) = 4.3; Δ7Li(acetic-whole) = 9.4‰). This initial study suggests that lithium isotopes have the potential to reveal the role of liquid water in the early solar system.

Quantifying hydrogen-deuterium exchange of meteoritic dicarboxylic acids during aqueous extraction

NASA Astrophysics Data System (ADS)

Fuller, M.; Huang, Y.

2003-03-01

Hydrogen isotope ratios of organic compounds in carbonaceous chondrites provide critical information about their origins and evolutionary history. However, because many of these compounds are obtained by aqueous extraction, the degree of hydrogen-deuterium (H/D) exchange that occurs during the process needs to be quantitatively evaluated. This study uses compound- specific hydrogen isotopic analysis to quantify the H/D exchange during aqueous extraction. Three common meteoritic dicarboxylic acids (succinic, glutaric, and 2-methyl glutaric acids) were refluxed under conditions simulating the extraction process. Changes in D values of the dicarboxylic acids were measured following the reflux experiments. A pseudo-first order rate law was used to model the H/D exchange rates which were then used to calculate the isotope exchange resulting from aqueous extraction. The degree of H/D exchange varies as a result of differences in molecular structure, the alkalinity of the extraction solution and presence/absence of meteorite powder. However, our model indicates that succinic, glutaric, and 2-methyl glutaric acids with a D of 1800 would experience isotope changes of 38, 10, and 6, respectively during the extraction process. Therefore, the overall change in D values of the dicarboxylic acids during the aqueous extraction process is negligible. We also demonstrate that H/D exchange occurs on the chiral -carbon in 2-methyl glutaric acid. The results suggest that the racemic mixture of 2-methyl glutaric acid in the Tagish Lake meteorite could result from post-synthesis aqueous alteration. The approach employed in this study can also be used to quantify H/D exchange for other important meteoritic compounds such as amino acids.

Isotopic Composition of Carbonates in Antarctic Ordinary Chondrites and Miller Range Nakhlites: Insights into Martian Amazonian Aqueous Alteration

NASA Technical Reports Server (NTRS)

Evans, M. E.; Niles, P. B.; Chapman, P.

2017-01-01

The martian surface contains features of ancient fluvial systems. Stable isotope analysis of carbonates that form in aqueous systems can reveal their formation conditions. The Nakhlite meteorites originally formed on Mars 1.3 Ga and were later exposed to aqueous fluids that left behind carbonate minerals [1], thus analysis of these carbonates can provide data to understand Amazonian climate conditions on Mars. Carbonates found in the Nakhlite meteorites contain a range of delta(sup 13)C values, which may be either martian carbonates or terrestrial contamination. To better under-stand terrestrial weathering products and martian carbonate formation processes, we conducted a set of carbonate isotope analyses on Antarctic meteorites focusing on Miller Range (MIL) Nakhlites as well as Ordinary Chondrites (OCs) (Figure 1)[1-11] [12]. OCs of petrology type H, L, and LL 3-6 were selected since they are not expected to contain preterrestrial carbonates, yet they have visible evaporite minerals on the fusion crust indicating terrestrial alteration. These cryogenically formed terrestrial carbonates may also provide an analog for cryogenic carbonate formation on Mars.

Unraveling the History of Meridiani Planum, Mars: New Chemical Clues From the Rim of Endeavour Crater

NASA Astrophysics Data System (ADS)

Fraeman, Abigail A.

2018-03-01

Mittlefehldt et al. (2018, https://doi.org/10.1002/2017JE005474) synthesize Alpha Particle X-Ray Spectrometer chemical measurements along more than 4.5 km of Endeavour crater's rim. Their analyses clarify details of Endeavour's geologic history, including evidence for three to four distinct episodes of aqueous alteration. Fracture-driven aqueous systems and Mn mobility are particularly important both here and at Curiosity's landing site on the opposite side of the planet. The detailed documentation of Alpha Particle X-Ray Spectrometer data products within this paper will be a key reference for researchers who want to perform future work on questions related to Mars aqueous geochemistry, impact processes, and Martian crustal and atmospheric evolution.

The Iodine-Xenon System in Outer and Inner Portions of Chondrules from the Unnamed Antarctic LL3 Chondrite

NASA Technical Reports Server (NTRS)

Meshik, A. P.; Pravdivtseva, O. V.; Hohenberg, C. M.; Amelin, Y.

2004-01-01

Alteration processes may affect I-Xe system in unequilibrated ordinary chondrites. It was shown that at the edges, where a contribution is made by matrix material around the rim, *Xe-129/Xe-128 values are generally lower (later apparent ages) than in the main chondrule mass. In this work we attempted to investigate whether thermal metamorphism can affect the I-Xe system in LL3 chondrites which did not experienced aqueous alteration.

Workshop on Parent-Body and Nebular Modification of Chondritic Materials

NASA Technical Reports Server (NTRS)

Zolensky, M. E. (Editor); Krot, A. N. (Editor); Scott, E. R. D. (Editor)

1997-01-01

Topics considered include: thermal Metamorphosed Antarctic CM and CI Carbonaceous Chondrites in Japanese Collections, and Transformation Processes of Phyllosilicates; use of Oxygen Isotopes to Constrain the Nebular and Asteroidal Modification of Chondritic Materials; effect of Revised Nebular Water Distribution on Enstatite Chondrite Formation; interstellar Hydroxyls in Meteoritic Chondrules: Implications for the Origin of Water in the Inner Solar System; theoretical Models and Experimental Studies of Gas-Grain Chemistry in the Solar Nebula; chemical Alteration of Chondrules on Parent Bodies; thermal Quenching of Silicate Grains in Protostellar Sources; an Experimental Study of Magnetite Formation in the Solar Nebula; the Kaidun Meteorite: Evidence for Pre- and Postaccretionary Aqueous Alteration; a Transmission Electron Microscope Study of the Matrix Mineralogy of the Leoville CV3 (Reduced-Group) Carbonaceous Chondrite: Nebular and Parent-Body Features; rubidium-Strontium Isotopic Systematic of Chondrules from the Antarctic CV Chondrites Yamato 86751 and Yamato 86009: Additional Evidence for Late Parent-Body Modification; oxygen-Fugacity Indicators in Carbonaceous Chondrites: Parent-Body Alteration or High-Temperature Nebular Oxidation; thermodynamic Modeling of Aqueous Alteration in CV Chondrites; asteroidal Modification of C and O Chondrites: Myths and Models; oxygen Fugacity in the Solar Nebular; and the History of Metal and Sulfides in Chondrites.

Amoeboid Olivine Aggregates in Antarctic CR Chondrites: Petrologic Variations Among CR Chondrites

NASA Astrophysics Data System (ADS)

Komatsu, M.; Fagan, T. J.; Yamaguchi, A.; Mikouchi, T.; Yasutake, M.; Zolensky, M. E.

2017-07-01

A set of Antarctic CRs were examined to see intra-group variations. AOAs in Y-791498, Y-793261, and A-881828 have largely escaped from aqueous alteration. Extensive aqueous alteration in A-881595 and shock deformation in Y-982405 are also observed.

Computer modeling of the mineralogy of the Martian surface, as modified by aqueous alteration

NASA Technical Reports Server (NTRS)

Zolensky, M. E.; Bourcier, W. L.; Gooding, J. L.

1988-01-01

Mineralogical constraints can be placed on the Martian surface by assuming chemical equilibria among the surface rocks, atmosphere and hypothesized percolating groundwater. A study was made of possible Martian surface mineralogy, as modified by the action of aqueous alteration, using the EQ3/6 computer codes. These codes calculate gas fugacities, aqueous speciation, ionic strength, pH, Eh and concentration and degree of mineral saturation for complex aqueous systems. Thus, these codes are also able to consider mineralogical solid solutions. These codes are able to predict the likely alteration phases which will occur as the result of weathering on the Martian surface. Knowledge of the stability conditions of these phases will then assist in the definition of the specifications for the sample canister of the proposed Martian sample return mission. The model and its results are discussed.

Alteration and formation of rims on the CM parent body

NASA Technical Reports Server (NTRS)

Browning, Lauren B.; Mcsween, Harry Y., Jr.; Zolensky, Michael

1994-01-01

All types of coarse-grained components in CM chondrites are surrounded by fine-grained dust coatings, but the origin of these rims is not yet clear. Although a strictly nebular origin seems likely for rims in the relatively unaltered type 3 chondrites, the rims in CM chondrites are dominated by secondary alteration phases. It has been argued that either the coarse-grained cores accreted altered rim materials while still in the nebula or that alteration of primary rim phases occurred on the CM parent body. To constrain the origin of alteration phases in rim material, we have analyzed the textures and mineral associations from 10 CM chondritic falls by optical and scanning electron microscopy. Our results indicate that the secondary phases in CM chondritic rims were produced by parent body fluid-rock interactions which redefined some primary rim textures and may have produced, in some cases, both coarse-grained components and the rims that surround them. Textural features demonstrate the interactive exchange of alteration fluids between rims, matrix, and chondrules on the CM parent body. For example, most matrix-rim contacts are gradational, suggesting the synchronous alteration of both components. Several observations suggest the possibility of in situ rim production. For example, tochilinite and phyllosilicates commonly form rims around matrix carbonates, which are generally believed to have precipitated from alteration fluids on the CM parent body. This suggests that the rims surrounding matrix carbonates may also have been produced by alteration processes. Partially replaced chondrule olivines bear a striking resemblance to many rimmed olivines in the matrix which suggests, by analogy, that site-specific precipitation of S-bearing phases may also be responsible for the occurrence of many tochilinite-rich rims around isolated matrix olivines. Non-silicate rims precipitate around olivines of any composition, but the process is most effective for fayalitic olivines. Most of the remaining olivines in CM chondrites are relatively Mg-rich, which suggests that the precipitation of S-bearing rims on olivines may not have been an important process in the aqueous alteration of CM chondrites. We conclude that: (1) precursor rim materials in CM chondrites were subjected to pervasive aqueous alteration on the CM parent body; and (2) textures and mineral associations observed in CM chondrites also suggest the possibility of in situ rim production.

Clues on Past Climatic Environments and Subsurface Flow in Mars from Aqueous Alteration Minerals Found in Nakhla and Allan Hills 84001 Meteorites

NASA Astrophysics Data System (ADS)

Trigo-Rodriguez, J. M.; Moyano-Cambero, C. E.; Donoso, J. A.; Benito-Moreno, M. I.; Alonso-Azcárate, J.

2018-04-01

The study of aqueous alteration minerals like Fe-Mg-Ca carbonates in Allan Hills 84001 or iddingsite and magnetite in Nakhla meteorite allow us to constrain their formation conditions and water availability at 4 and 1.3 Ga ago, respectively.

Evidence for Calcium Carbonate at the Phoenix Landing Site

NASA Technical Reports Server (NTRS)

Boynton, W. V.; Ming, D. W.; Sutter, B.; Arvidson, R. E.; Hoffman, J.; Niles, P. B.; Smith, P.

2009-01-01

The Phoenix mission has recently finished its study of the north polar environment of Mars with the aim to help understand both the current climate and to put constraints on past climate. An important part of understanding the past climate is the study of secondary minerals, those formed by reaction with volatile compounds such as H2O and CO2. This work describes observations made by the Thermal and Evolved-Gas Analyzer (TEGA) on the Phoenix Lander related to carbonate minerals. Carbonates are generally considered to be products of aqueous processes. A wet and warmer climate during the early history of Mars coupled with a much denser CO2 atmosphere are ideal conditions for the aqueous alteration of basaltic materials and the subsequent formation of carbonates. Carbonates (Mg- and Ca-rich) are predicted to be thermodynamically stable minerals in the present martian environment, however, there have been only a few indications of carbonates on the surface by a host of orbiting and landed missions to Mars. Carbonates (Mg-rich) have been suggested to be a component (2-5 wt %) of the martian global dust based upon orbital thermal emission spectroscopy. The identifications, based on the presence of a 1480 cm-1 absorption feature, are consistent with Mgcarbonates. A similar feature is observed in brighter, undisturbed soils by Mini-TES on the Gusev plains. Recently, Mg-rich carbonates have been identified in the Nili Fossae region by the CRISM instrument onboard the Mars Reconnaissance Orbiter. Carbonates have also been confirmed as aqueous alteration phases in martian meteorites so it is puzzling why there have not been more discoveries of carbonates by landers, rovers, and orbiters. Carbonates may hold important clues about the history of liquid water and aqueous processes on the surface of Mars.

Investigation of acyl migration in mono- and dicaffeoylquinic acids under aqueous basic, aqueous acidic, and dry roasting conditions.

PubMed

Deshpande, Sagar; Jaiswal, Rakesh; Matei, Marius Febi; Kuhnert, Nikolai

2014-09-17

Acyl migration in chlorogenic acids describes the process of migration of cinnamoyl moieties from one quinic acid alcohol group to another, thus interconverting chlorogenic acid regioisomers. It therefore constitutes a special case of transesterification reaction. Acyl migration constitutes an important reaction pathway in both coffee roasting and brewing, altering the structure of chlorogenic acid initially present in the green coffee bean. In this contribution we describe detailed and comprehensive mechanistic studies comparing inter- and intramolecular acyl migration involving the seven most common chlorogenic acids in coffee. We employe aqueous acidic and basic conditions mimicking the brewing of coffee along with dry roasting conditions. We show that under aqueous basic conditions intramolecular acyl migration is fully reversible with basic hydrolysis competing with acyl migration. 3-Caffeoylquinic acid was shown to be most labile to basic hydrolysis. We additionally show that the acyl migration process is strongly pH dependent with increased transesterification taking place at basic pH. Under dry roasting conditions acyl migration competes with dehydration to form lactones. We argue that acyl migration precedes lactonization, with 3-caffeoylquinic acid lactone being the predominant product.

Metastable equilibria among dicarboxylic acids and the oxidation state during aqueous alteration on the CM2 chondrite parent body

NASA Astrophysics Data System (ADS)

McAlister, Jason A.; Kettler, Richard M.

2008-01-01

Linear saturated dicarboxylic acids are present in carbonaceous chondrite samples at concentrations that suggest aqueous alteration under conditions of metastable equilibrium. In this study, previously published values of dicarboxylic acid concentrations measured in Murchison, Yamato-791198, and Tagish Lake carbonaceous chondrites are converted to aqueous activities during aqueous alteration assuming water:rock ratios that range from 1:10 to 10:1. Logarithmic plots of the aqueous activities of any two dicarboxylic acids are proximal to lines whose slope is fixed by the stoichiometry of reactions describing the oxidation-reduction equilibrium between the two species. The precise position of any line is controlled by the equilibrium constant of the reaction relating the species and the hydrogen fugacity for the reaction of interest. Reactions among succinic (C4), glutaric (C5), and adipic (C6) acids obtained from CM2 chondrites show evidence of metastable equilibrium and yield logf values that agree to within 0.3 log units at 298.15 K and 0.6 log units at 473.15 K. At a water:rock ratio of 1:1, metastable equilibrium among succinic, glutaric, and adipic acids results in calculated logf values during aqueous alteration that range from -6.2 at 298.15 K to -3.3 at 373.15 K. These values are consistent with those obtained in previous work on carbonaceous chondrites and with metastable equilibrium at temperatures ranging from 300 to 355 K in contact with cronstedtite + magnetite.

Relationship Between Iron Valence States of Serpentine in CM Chondrites and Their Aqueous Alteration Degrees

NASA Technical Reports Server (NTRS)

Mikouchi, T.; Zolensky, M.; Satake, W.; Le, L.

2012-01-01

The 0.6-0.7 micron absorption band observed for C-type asteroids is caused by the presence of Fe(3+) in phyllosilicates . Because Fe-bearing phyllosilicates, especially serpentine, are the most dominant product of aqueous alteration in the most abundant carbonaceous chondrites, CM chondrites, it is important to understand the crystal chemistry of serpentine in CM chondrites to better understand spectral features of C-type asteroids. CM chondrites show variable degrees of aqueous alteration, which should be related to iron valences in serpentine. It is predicted that the Fe(3+)/Sum of (Fe) ratios of serpentine in CM chondrites decrease as alteration proceeds by Si and Fe(3+) substitutions from end-member cronstedtite to serpentine, which should be apparent in the absorption intensity of the 0.6-0.7 micron band from C-type asteroids. In fact, the JAXA Hayabusa 2 target (C-type asteroid: 1993 JU3) exhibits heterogeneous spectral features (0.7 micron absorption band disappears by rotation). From these points of view, we have analyzed iron valences of matrix serpentine in several CM chondrites which span the entire observed range of aqueous alteration using Synchrotron Radiation X-ray Absorption Near-Edge Structure (SR-XANES). In this abstract we discuss the relationship between obtained Fe(3+)/Sum of (Fe) ratios and alteration degrees by adding new data to our previous studies

Epigenetic formation of amethyst-bearing geodes from Los Catalanes gemological district, Artigas, Uruguay, southern Paraná Magmatic Province

NASA Astrophysics Data System (ADS)

Duarte, L. C.; Hartmann, L. A.; Vasconcellos, M. A. Z.; Medeiros, J. T. N.; Theye, T.

2009-07-01

Giant geodes (up to 4 m long) in the massive central portions of altered basalt lavas from the Paraná Magmatic Province, southern Brazil and Uruguay, form a world-class source of amethyst and agate. Although the origin of the cavities has been ascribed to degassing of the lava at > 1150 °C, field evidence is conclusive that the giant amethyst-agate-filled geodes were formed by hydrothermal processes at low temperatures. We propose an epigenetic and hydrothermal model for the origin of giant geodes. This model includes hydrothermal brecciation during an early brittle stage and the late formation of the cavities (geodes). In the brittle stage an overpressured aqueous fluid affected the basalt in a P, T field delimited by temperatures between 100 and 150 °C and vapor pressures between 1.2 and 5.5 bar. The fluids were capable of lifting the roof and fracturing the host rock along new subhorizontal and subvertical fractures and breccias in the massive lava. The formation of these structures occurred at shallow depths, unit-by-unit. To open the cavities, dissolution of the now altered basalt to clay minerals is necessary. The process is closely linked to the highest alteration grade of mineralized lavas in Los Catalanes gemological district. Dissolution processes are observed in micrometer-scale in the studied basalts. The primary mineralogy, consisting of labradorite (± andesine) +augite + pigeonite + mesostasis (K-rich), was altered during the interaction of large volumes of hot aqueous fluid with the rock. The alteration of pigeonite and its replacement by smectite is observed around the cavities, followed by the precipitation of amorphous silica and microcrystalline quartz in clay-rich sites. Associated zeolites (heulandite + clinoptilolite) fill the newly formed cavities in progressive stages of hydrothermal alteration. Our data indicate that the temperatures were less than 200 °C and probably less than 150 °C; cavity formation occurred after alteration of the basalt to more than 60 vol.% clay minerals. We thus suggest that cavities related to geode formation are of epigenetic origin.

Alteration of immature sedimentary rocks on Earth and Mars. Recording Aqueous and Surface-atmosphere Processes

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

Cannon, Kenneth M.; Mustard, John F.; Salvatore, Mark R.

The rock alteration and rind formation in analog environments like Antarctica may provide clues to rock alteration and therefore paleoclimates on Mars. Clastic sedimentary rocks derived from basaltic sources have been studied in situ by martian rovers and are likely abundant on the surface of Mars. Moreover, how such rock types undergo alteration when exposed to different environmental conditions is poorly understood compared with alteration of intact basaltic flows. Here we characterize alteration in the chemically immature Carapace Sandstone from Antarctica, a terrestrial analog for martian sedimentary rocks. We employ a variety of measurements similar to those used on previousmore » and current Mars missions. Laboratory techniques included bulk chemistry, powder X-ray diffraction (XRD), hyperspectral imaging and X-ray absorption spectroscopy. Through these methods we find that primary basaltic material in the Carapace Sandstone is pervasively altered to hydrated clay minerals and palagonite as a result of water–rock interaction. A thick orange rind is forming in current Antarctic conditions, superimposing this previous aqueous alteration signature. The rind exhibits a higher reflectance at visible-near infrared wavelengths than the rock interior, with an enhanced ferric absorption edge likely due to an increase in Fe 3+ of existing phases or the formation of minor iron (oxy)hydroxides. This alteration sequence in the Carapace Sandstone results from decreased water–rock interaction over time, and weathering in a cold, dry environment, mimicking a similar transition early in martian history. This transition may be recorded in sedimentary rocks on Mars through a similar superimposition mechanism, capturing past climate changes at the hand sample scale. These results also suggest that basalt-derived sediments could have sourced significant volumes of hydrated minerals on early Mars due to their greater permeability compared with intact igneous rocks.« less

The formation and alteration of the Renazzo-like carbonaceous chondrites I: Implications of bulk-oxygen isotopic composition

NASA Astrophysics Data System (ADS)

Schrader, Devin L.; Franchi, Ian A.; Connolly, Harold C., Jr.; Greenwood, Richard C.; Lauretta, Dante S.; Gibson, Jenny M.

2011-01-01

To better understand the role of aqueous alteration on the CR chondrite parent asteroid, a whole-rock oxygen isotopic study of 20 meteorites classified as Renazzo-like carbonaceous chondrites (CR) was conducted. The CR chondrites analyzed for their oxygen isotopes were Dhofar 1432, Elephant Moraine (EET) 87770, EET 92042, EET 96259, Gao-Guenie (b), Graves Nunataks (GRA) 95229, GRA 06100, Grosvenor Mountains (GRO) 95577, GRO 03116, LaPaz Ice Field (LAP) 02342, LAP 04720, Meteorite Hills (MET) 00426, North West Africa (NWA) 801, Pecora Escarpment (PCA) 91082, Queen Alexandra Range (QUE) 94603, QUE 99177, and Yamato-793495 (Y-793495). Three of the meteorites, Asuka-881595 (A-881595), GRA 98025, and MET 01017, were found not to be CR chondrites. The remaining samples concur petrographically and with the well-established oxygen-isotope mixing line for the CR chondrites. Their position along this mixing line is controlled both by the primary oxygen-isotopic composition of their individual components and their relative degree of aqueous alteration. Combined with literature data and that of this study, we recommend the slope for the CR-mixing line to be 0.70 ± 0.04 (2σ), with a δ 17O-intercept of -2.23 ± 0.14 (2σ). Thin sections of Al Rais, Shişr 033, Renazzo, and all but 3 samples analyzed for oxygen isotopes were studied petrographically. The abundance of individual components is heterogeneous among the CR chondrites, but FeO-poor chondrules and matrix are the most abundant constituents and therefore, dominate the whole-rock isotopic composition. The potential accreted ice abundance, physico-chemical conditions of aqueous alteration (e.g. temperature and composition of the fluid) and its duration control the degree of alteration of individual CR chondrites. Combined with literature data, we suggest that LAP 02342 was exposed to lower temperature fluid during alteration than GRA 95229. With only two falls, terrestrial alteration of the CR chondrites complicates the interpretation of their whole rock isotopic composition, particularly in the most aqueously altered samples, and those with relatively higher matrix abundances. We report that QUE 99177 is the isotopically lightest whole rock CR chondrite known (δ 18O = -2.29‰, δ 17O = -4.08‰), possibly due to isotopically light unaltered matrix; which shows that the anhydrous component of the CR chondrites is isotopically lighter than previously thought. Although it experienced aqueous alteration, QUE 99177 provides the best approximation of the pristine CR-chondrite parent body's oxygen-isotopic composition, before aqueous alteration took place. Using this value as a new upper limit on the anhydrous component of the CR chondrites, water/rock ratios were recalculated and found to be higher than previously thought; ratios now range from 0.281 to 1.157. We also find that, according to their oxygen isotopes, a large number of CR chondrites appear to be minimally aqueously altered; although sample heterogeneity complicates this interpretation.

Wet, Carbonaceous Asteroids: Altering Minerals, Changing Amino Acids

NASA Astrophysics Data System (ADS)

Taylor, G. J.

2011-04-01

Many carbonaceous chondrites contain alteration products from water-rock interactions at low temperature and organic compounds. A fascinating fact known for decades is the presence in some of them of an assortment of organic compounds, including amino acids, sometimes called the building blocks of life. Murchison and other CM carbonaceous chondrites contain hundreds of amino acids. Early measurements indicated that the amino acids in carbonaceous chondrites had equal proportions of L- and D-structures, a situation called racemic. This was in sharp contrast to life on Earth, which heavily favors L- forms. However, beginning in 1997, John Cronin and Sandra Pizzarello (Arizona State University) found L- excesses in isovaline and several other amino acids in the Murchison carbonaceous chondrite. In 2009, Daniel Glavin and Jason Dworkin (Astrobiology Analytical Lab, Goddard Space Flight Center) reported the first independent confirmation of L-isovaline excesses in Murchison using a different analytical technique than employed by Cronin and Pizzarello. Inspired by this work, Daniel Glavin, Michael Callahan, Jason Dworkin, and Jamie Elsila (Astrobiology Analytical Lab, Goddard Space Flight Center), have done an extensive study of the abundance and symmetry of amino acids in carbonaceous chondrites that experienced a range of alteration by water in their parent asteroids. The results show that amino acids are more abundant in the less altered meteorites, implying that aqueous processing changes the mix of amino acids. They also confirmed the enrichment in L-structures of some amino acids, especially isovaline, confirming earlier work. The authors suggest that aqueously-altered planetesimals might have seeded the early Earth with nonracemic amino acids, perhaps explaining why life from microorganisms to people use only L- forms to make proteins. The initial imbalance caused by non-biologic processes in wet asteroids might have been amplified by life on Earth. Alternatively, the same processes that produced the L-amino acid excesses in carbonaceous asteroids also operated on the early Earth.

Ancient impact and aqueous processes at Endeavour Crater, Mars

USGS Publications Warehouse

Squyres, S. W.; Arvidson, R. E.; Bell, J.F.; Calef, F.J.; Clark, B. C.; Cohen, B. A.; Crumpler, L.A.; de Souza, P. A.; Farrand, W. H.; Gellert, Ralf; Grant, J.; Herkenhoff, K. E.; Hurowitz, J.A.; Johnson, J. R.; Jolliff, B.L.; Knoll, A.H.; Li, R.; McLennan, S.M.; Ming, D. W.; Mittlefehldt, D. W.; Parker, T.J.; Paulsen, G.; Rice, M.S.; Ruff, S.W.; Schröder, C.; Yen, A. S.; Zacny, K.

2012-01-01

The rover Opportunity has investigated the rim of Endeavour Crater, a large ancient impact crater on Mars. Basaltic breccias produced by the impact form the rim deposits, with stratigraphy similar to that observed at similar-sized craters on Earth. Highly localized zinc enrichments in some breccia materials suggest hydrothermal alteration of rim deposits. Gypsum-rich veins cut sedimentary rocks adjacent to the crater rim. The gypsum was precipitated from low-temperature aqueous fluids flowing upward from the ancient materials of the rim, leading temporarily to potentially habitable conditions and providing some of the waters involved in formation of the ubiquitous sulfate-rich sandstones of the Meridiani region.

Hydrothermal Alteration at Lonar Crater, India and Elemental Variations in Impact Crater Clays

NASA Technical Reports Server (NTRS)

Newsom, H. E.; Nelson, M. J.; Shearer, C. K.; Misra, S.; Narasimham, V.

2005-01-01

The role of hydrothermal alteration and chemical transport involving impact craters could have occurred on Mars, the poles of Mercury and the Moon, and other small bodies. We are studying terrestrial craters of various sizes in different environments to better understand aqueous alteration and chemical transport processes. The Lonar crater in India (1.8 km diameter) is particularly interesting being the only impact crater in basalt. In January of 2004, during fieldwork in the ejecta blanket around the rim of the Lonar crater we discovered alteration zones not previously described at this crater. The alteration of the ejecta blanket could represent evidence of localized hydrothermal activity. Such activity is consistent with the presence of large amounts of impact melt in the ejecta blanket. Map of one area on the north rim of the crater containing highly altered zones at least 3 m deep is shown.

Na, Mg, Ni and Cs distribution and speciation after long-term alteration of a simulated nuclear waste glass: A micro-XAS/XRF/XRD and wet chemical study

NASA Astrophysics Data System (ADS)

Curti, Enzo; Dähn, Rainer; Farges, François; Vespa, Marika

2009-04-01

Microscopic distribution and speciation of Na, Mg, Ni and Cs in a simulated (inactive) nuclear waste glass were studied using micro X-ray fluorescence (μ-XRF) and micro X-ray absorption spectroscopy (μ-XAS), after aqueous leaching during 12 years at 90 °C. Na and Mg are major constituents of the glass that can be used to determine the progress of the glass corrosion process and the nature of secondary alteration phases. Ni and Cs represent dose determining long-lived radionuclides ( 59Ni, 135Cs) in vitrified nuclear waste. The Na-Mg μ-XRF maps revealed that the core regions of the glass fragments are apparently unaltered and compositionally homogeneous, whereas rims and interstitial spaces are enriched with Mg-rich smectite formed during the leaching process. The micro X-ray absorption near edge structure (μ-XANES) spectra collected at the Mg K-edge in the altered zones show three sharp resonances typical for crystalline Mg-silicates. These resonances are distinctive of Mg occupying undistorted octahedral positions. In contrast, the μ-XANES spectra collected in the core zones of the glass fragments lack this resonance pattern and are identical to the spectra measured on the pristine (unleached) MW glass. Micro extended X-ray absorption fine structure (μ-EXAFS) and μ-XANES analyses at the Ni K-edge revealed three distinct Ni(II) species: (a) Ni uniformly distributed in the glass matrix, (b) micro-inclusions with high Ni concentrations and (c) Ni associated to the Mg-clay. The comparison with reference spectra of unleached MW and other Ni-bearing silicate glasses indicated that species (a) represents the original coordinative environment of Ni in the glass. The μ-EXAFS analyses revealed that species (b) is structural Ni in trevorite (NiFe 2O 4), which probably formed through unmixing processes during the cooling of the glass melt. The μ-EXAFS of species (c) could be successfully modeled assuming specific adsorption or incorporation of Ni into the lattice of trioctahedral Mg-clay minerals. Alternative models assuming other elements (Ni, Al, Fe) in addition to Mg in the second shell could not be fitted successfully. Aqueous concentration data were used to calculate the speciation of the leaching solutions. Saturation index (SI) calculations indicate undersaturation with respect to NiCO 3 and NiSO 4·7H 2O, but oversaturation with respect to β-Ni(OH) 2. The latter result is probably due to the omission of Ni borate and Ni silicate complexes in the speciation calculations, for which formation constants are not available. With the help of estimation techniques, we could infer that such complexes would dominate the Ni speciation and consequently reduce the SI below the saturation of β-Ni(OH) 2. The μ-XRF maps show that Cs is uniformly distributed in the MW glass, since no region with high Cs concentration could be detected. The Cs L III-edge μ-XAS spectra were all very similar independently of the degree of alteration, indicating similar coordination environments of Cs in the core regions of the glass as well as in the secondary clays. These spectra largely differ from that measured for pollucite (a potential secondary Cs-phase in altered glasses) implying that the coordination environments of Cs in the MW glass and in pollucite are fundamentally different. The present study shows that μ-XRF and μ-XAS are essential tools in determining the fate and the retention mechanisms of radionuclides released from nuclear waste during aqueous alteration. Our spectroscopic analyses allowed us to exclude formation of specific Ni and Cs secondary solids (e.g. nepouite, β-Ni(OH) 2, pollucite) during the aqueous alteration. Ni and Cs are instead distributed as trace elements in the alteration phases formed by major elements during the leaching process. Our results imply that solid solution and/or adsorption equilibria, rather than pure phase solubility equilibria, are the adequate chemical models to determine Ni and Cs aqueous concentrations in performance assessments for radioactive waste repositories.

Water in the early solar system: Mid-infrared studies of aqueous alteration on asteroids.

NASA Astrophysics Data System (ADS)

McAdam, Margaret M.; Sunshine, Jessica M.; Kelley, Michael S.; Trilling, David E.

2017-10-01

This work investigates the distribution of water in the early Solar System by connecting asteroids to carbonaceous chondrite meteorites using spectroscopy. Aqueous alteration or the chemical reaction between liquid water and silicates on the parent asteroid, has extensively affected several groups of carbonaceous chondrites. The degree of alteration or amount of hydrated minerals produced depends on a number of factors including the abundance of coaccreted water-ice, the internal distribution of water in the parent body and the setting of alteration (e.g., open vs. closed setting). Despite this complexity which is still under investigation, the mineralogical changes produced by aqueous alteration are well understood (e.g., Howard et al., 2015). The mid-infrared spectral region has been shown to be a tool for estimating the degree of alteration of asteroids and meteorites remotely (McAdam et al., 2015). Specifically, mid-infrared spectral features changes continuously with degree of alteration. In this region meteorites can be categorized into four groups based on their spectral characteristics: anhydrous, less altered, intermediately altered and highly altered. We present the estimated degrees of alteration for 73 main belt asteroids using these results. Hydrated minerals appear to be widespread in the main belt and asteroids have variable degrees of alteration. There does not appear to be any relationship between the estimated degree of alteration and size, albedo or heliocentric distance. This indicates that water-ice must have been a significant component of the solar nebula in the 2-5 AU region during the time of carbonaceous chondrite accretion (~2.7-4 Ma post-CAI formation; Sugiura and Fujiya, 2014). The snow-line therefore must have been in this region during this epoch. Furthermore, local heterogeneities of water-ice were likely common since asteroids of all sizes and heliocentric distances may exhibit any degree from anhydrous to highly altered. Additionally, asteroids that have been shown to have water-ice on their surfaces (e.g., Takir and Emery, 2012) appear to have hydrated minerals. This indicates that while these asteroids have water-ice, its presence did not prevent aqueous alteration.

Formation and transformations of Fe-rich serpentines by asteroidal aqueous alteration processes: A nanoscale study of the Murray chondrite

NASA Astrophysics Data System (ADS)

Elmaleh, Agnès; Bourdelle, Franck; Caste, Florent; Benzerara, Karim; Leroux, Hugues; Devouard, Bertrand

2015-06-01

Fe-rich serpentines are an abundant product of the early aqueous alteration events that affected the parent bodies of CM carbonaceous chondrites. Alteration assemblages in these meteorites show a large chemical variability and although water-rock interactions occurred under anoxic conditions, serpentines contain high amounts of ferric iron. To date very few studies have documented Fe valence variations in alteration assemblages of carbonaceous chondrites, limiting the understanding of the oxidation mechanisms. Here, we report results from a nanoscale study of a calcium-aluminum-rich inclusion (CAI) from the Murray chondrite, in which alteration resulted in Fe import and Ca export by the fluid phase and in massive Fe-rich serpentines formation. We combined scanning and transmission electron microscopies and scanning transmission X-ray microscopy for characterizing the crystal chemistry of Fe-serpentines. We used reference minerals with known crystallographic orientations to quantify the Fe valence state in Fe-rich serpentines using X-ray absorption spectroscopy at the Fe L2,3-edges, yielding a robust methodology that would prove valuable for studying oxidation processes in other terrestrial or extra-terrestrial cases of serpentinization. We suggest that aqueous Fe2+ was transported to the initially Fe-depleted CAI, where local changes in pH conditions, and possibly mineral catalysis by spinel promoted the partial oxidation of Fe2+ into Fe3+ by water and the formation of Fe-rich serpentines close to the cronstedtite endmember. Such mechanisms produce H2, which opens interesting perspectives as hydrogen may have reacted with carbon species, or escaped and yield increasingly oxidizing conditions in the parent asteroid. From the results of this nanoscale study, we also propose transformations of the initial cronstedtite, destabilized by later input of Al- and Mg-rich solutions, leading to Fe2+ leaching from serpentines, as well as to random serpentine-chlorite interstratifications. Such transformations towards polysomatic assemblages that are un-equilibrated from the structural, chemical and redox point of views are probably controlled by the various rates of alteration of primary minerals, but also by porosity gradients, as in terrestrial hydrothermal systems. We suggest that the proposed mechanisms may have played a role in the early formation of (Fe2+,Fe3+)-rich serpentines documented in CM chondrites, as well as in their transformation with on-going alteration towards Fe-poorer compositions inferred from previous petrologic, mineralogical and magnetic studies of CM chondrites.

Water Transport and the Evolution of CM Parent Bodies

NASA Technical Reports Server (NTRS)

Coker, R.; Cohen, B.

2014-01-01

Extraterrestrial water-bearing minerals are of great importance both for understanding the formation and evolution of the solar system and for supporting future human activities in space. Asteroids are the primary source of meteorites, many of which show evidence of an early heating episode and varying degrees of aqueous alteration. The origin and characterization of hydrated minerals (minerals containing H2O or OH) among both the main-belt and near-earth asteroids is important for understanding a wide range of solar system formation and evolutionary processes, as well as for planning for human exploration. Current hypotheses postulate asteroids began as mixtures of water ice and anhydrous silicates. A heating event early in solar system history was then responsible for melting the ice and driving aqueous alteration. The link between asteroids and meteorites is forged by reflectance spectra, which show 3-µm bands indicative of bound OH or H2O on the C-class asteroids, which are believed to be the parent bodies of the carbonaceous chondrites in our collections. The conditions at which aqueous alteration occurred in the parent bodies of carbonaceous chondrites are thought to be well-constrained: at 0-25 C for less than 15 Myr after asteroid formation. In previous models, many scenarios exhibit peak temperatures of the rock and co-existing liquid water in more than 75 percent of the asteroid's volume rising to 150 C and higher, due to the exothermic hydration reactions triggering a thermal runaway effect. However, even in a high porosity, water-saturated asteroid very limited liquid water flow is predicted (distances of 100's nm at most). This contradiction has yet to be resolved. Still, it may be possible for water to become liquid even in the near-surface environment, for a long enough time to drive aqueous alteration before vaporizing or freezing then subliming. Thus, we are using physics- and chemistry-based models that include thermal and fluid transport as well as the effects of relevant chemical reactions, to investigate whether formation of hydrated minerals can occur in the surface and near-surface environments of carbonaceous type asteroids. These models will elucidate how the conditions within the parent body that cause internal aqueous alteration play themselves out at the asteroid's surface. We are using our models to determine whether the heat budget of 20-100-km bodies is sufficient to bring liquid water to the near-surface and cause mineral alteration, or whether additional heat input at the surface (i.e, by impacts) is needed to provide a transient liquid water source for mineral hydration without large- scale liquid water transport.

Reassessing the Formation of CK7 Northwest Africa (NWA) 8186

NASA Technical Reports Server (NTRS)

Srinivasan, P.; McCubbin, F. M.; Lapen, T. J.; Righter, M.; Agee, C. B.

2017-01-01

The classification of meteorites is commonly determined using isotopes, modal mineralogy, and bulk compositions [1]. Bulk rare earth elements (REEs) in meteorites are additionally utilized to understand parent body processes. Numerous authors have shown that chondritic groups exhibit REE patterns that may be attributable to their parent bodies [e.g. 2-4], and variations in abundances and concentrations of REEs may reflect early nebular processes, thermal metamorphism, and aqueous alteration on the parent body [5-6].

Co-processing as a tool to improve aqueous dispersibility of cellulose ethers.

PubMed

Sharma, Payal; Modi, Sameer R; Bansal, Arvind K

2015-01-01

Cellulose ethers are important materials with numerous applications in pharmaceutical industry. They are widely employed as stabilizers and viscosity enhancers for dispersed systems, binders in granulation process and as film formers for tablets. These polymers, however, exhibit challenge during preparation of their aqueous dispersions. Rapid hydration of their surfaces causes formation of a gel that prevents water from reaching the inner core of the particle. Moreover, the surfaces of these particles become sticky, thus leading to agglomeration, eventually reducing their dispersion kinetics. Numerous procedures have been tested to improve dispersibility of cellulose ethers. These include the use of cross-linking agents, alteration in the synthesis process, adjustment of water content of cellulose ether, modification by attaching hydrophobic substituents and co-processing using various excipients. Among these, co-processing has provided the most encouraging results. This review focuses on the molecular mechanisms responsible for the poor dispersibility of cellulose ethers and the role of co-processing technologies in overcoming the challenge. An attempt has been made to highlight various co-processing techniques and specific role of excipients used for co-processing.

Isotopic and Chemical Evidence for Primitive Aqueous Alteration in the Tagish Lake Meteorite

NASA Astrophysics Data System (ADS)

Sakuma, Keisuke; Hidaka, Hiroshi; Yoneda, Shigekazu

2018-01-01

Aqueous alteration is one of the primitive activities that occurred on meteorite parent bodies in the early solar system. The Tagish Lake meteorite is known to show an intense parent body aqueous alteration signature. In this study, quantitative analyses of the alkaline elements and isotopic analyses of Sr and Ba from acid leachates of TL (C2-ungrouped) were performed to investigate effects of aqueous alteration. The main purpose of this study is to search for isotopic evidence of extinct 135Cs from the Ba isotopic analyses in the chemical separates from the Tagish Lake meteorite. Barium isotopic data from the leachates show variable 135Ba isotopic anomalies (ε = ‑2.6 ∼ +3.6) which correlatewith 137Ba and 138Ba suggesting a heterogeneous distribution of s- and r-rich nucleosynthetic components in the early solar system. The 87Rb–87Sr and 135Cs–135Ba decay systems on TL in this study do not provide any chronological information. The disturbance of the TL chronometers is likely a reflection of the selective dissolution of Cs and Rb given the relatively higher mobility of Cs and Rb compared to Ba and Sr, respectively, during fluid mineral interactions.

Aqueous Alteration and Hydrogen Generation on Parent Bodies of Unequilibrated Ordinary Chondrites: Thermodynamic Modeling for the Semarkona Composition

NASA Technical Reports Server (NTRS)

Zolotov, M. Y.; Mironenko, M. V.; Shock, E. L.

2005-01-01

Ordinary chondrites are the most abundant class of meteorites that could represent rocky parts of solar system bodies. However, even the most primitive unequilibrated ordinary chondrites (UOC) reveal signs of mild alteration that affected the matrix and peripheral zones of chondrules. Major chemical changes include oxidation of kamacite, alteration of glass, removal of alkalis, Al, and Si from chondrules, and formation of phases enriched in halogens, alkalis, and hydrogen. Secondary mineralogical changes include formation of magnetite, ferrous olivine, fayalite, pentlandite, awaruite, smectites, phosphates, carbonates, and carbides. Aqueous alteration is consistent with the oxygen isotope data for magnetite. The presence of secondary magnetite, Ni-rich metal alloys, and ferrous silicates in UOC implies that H2O was the oxidizing agent. However, oxidation by H2O means that H2 is produced in each oxidative pathway. In turn, production of H2, and its redistribution and possible escape should have affected total pressure, as well as the oxidation state of gas, aqueous and mineral phases in the parent body. Here we use equilibrium thermodynamic modeling to explore water-rock reactions in UOC. The chemical composition of gas, aqueous, and mineral phases is considered.

Iron Oxidation Processes During Asteroidal Fluid-Rock Interactions: a Nanoscale Study of Serpentine-bearing Alteration Assemblages in the Murray Meteorite

NASA Astrophysics Data System (ADS)

Elmaleh, A.; Bourdelle, F.; Benzerara, K.; Caste, F.; Leroux, H.; Devouard, B.

2014-12-01

Carbonaceous chondrites of the CM and CI groups contain large amounts of water bound in minerals, attesting to early water-rock interactions on their parent bodies. In CM2 chondrites such as the Murray meteorite the alteration assemblages mostly consist of serpentines with variable chemical compositions. Even though chondritic serpentines formed from anoxic fluids, they contain significant amounts of ferric iron. In order to evaluate mass transfers and redox processes during alteration, we performed a study of a heavily altered calcium-aluminium-rich inclusion (CAI), at the nanometer scale (Transmission Electron Microscopy and Soft x-Ray Scanning Transmission Spectro-Microscopy, on ultra-thin sections prepared by Focused Ion Beam - FIB - milling). Using x-ray absorption spectroscopy at the Fe L2,3-edges, and based on literature references and on measurements of crystallographically oriented FIB foils of cronstedtite (the mixed-valence Fe endmember of serpentine) we estimated over 50% Fe3+ in alteration assemblages. We measured higher ferric iron proportions in mixed Fe,Mg,Al-serpentine/hydroxide disordered phases than in well-crystallized Al,Mg-bearing cronstedtite. We suggest that aqueous Fe2+ was transported to the initially Fe-depleted CAI. There, local changes in pH conditions and / or mineral catalysis would have promoted the partial oxidation of Fe. Later input of Al- and Mg-rich solutions might then have destabilized the initial serpentine, yielding assemblages un-equilibrated from the structural, chemical and redox point of views, similar to the polysomatic assemblages observed in terrestrial hydrothermal systems. Here, we illustrate the usefulness of such a combined study for better understanding the processes of hydration on the parent body of carbonaceous chondrites. Interestingly, as the reactions proposed for the oxidation of Fe generate hydrogen, reduction reactions - involving carbon species, for instance - are expected to follow the ones described here. Alternatively, given the high rate of diffusion of hydrogen some degree of H2 escape may be expected too, which would have induced increasingly oxidizing conditions during aqueous alteration.

Iron Mineralogy and Aqueous Alteration on Mars from the MER Moessbauer Spectrometers. Chapter 15

NASA Technical Reports Server (NTRS)

Morris, Richard V.; Klingelhoefer, Goestar

2007-01-01

The twin Mars Exploration Rovers Spirit (Gusev crater) and Opportunity (Meridiani Planum) used MIMOS II Moessbauer spectrometers to analyze martian surface materials in the first application of extraterrestrial Moessbauer spectroscopy. The instruments acquired spectra that identified the speciation of Fe according to oxidation state, coordination state, and mineralogical composition and provided quantitative information about the distribution of Fe among oxidation states, coordination states, and Fe-bearing phases. A total of 12 unique Fe-bearing phases were identified: Fe(2+) in olivine, pyroxene, and ilmenite; Fe(2+) and Fe(3+) in magnetite and chromite; Fe(3+) in nanophase ferric oxide (npOx), hematite, goethite, jarosite, an unassigned Fe3+ sulfate, and an unassigned Fe(3+) phase associated with jarosite; and Fe(0) in kamacite. Weakly altered basalts at Gusev crater (SO3 = 2.5 +/- 1.4 wt.% and Fe(3+)/Fe(sub T) = 0.24 +/- 0.11) are widespread on the Gusev plains and occur in less abundance on West Spur and Husband Hill in the Columbia Hills. Altered low-S rocks (SO3 = 5.2 +/- 2.0 wt.% and Fe(3+)/Fe(sub T) = 0.63 +/- 0.18) are the most common type of rock in the Columbia Hills. Ilm-bearing, weakly altered basalts were detected only in the Columbia Hills, as was the only occurrence of chromite in an altered low-S rock named Assemblee. Altered high-S rocks (SO3 > 14.2 wt.% and Fe(3+)/Fe(sub T) = 0.83 +/- 0.05) are the outcrop rocks of the ubiquitous Burns formation at Meridiani Planum. Two Fe(0)-bearing rocks at Meridiani Planum (Barberton and Heat Shield Rock) are meteorites. Laguna Class soil is weakly altered (SO3 = 6 +/- 2 wt.% and Fe(3+)/Fe(sub T) = 0.29 +/- 0.08) and widely distributed at both Gusev crater and Meridiani Planum, implying efficient global mixing processes or a global distribution of precursor rocks with comparable Fe mineralogical compositions. Paso Robles Class soil is heavily altered (SO3 approx. 31 wt.% and Fe(3+)/Fe(sub T) = 0.83 +/- 0.05), is relatively uncommon, and occurs as subsurface deposits in the Columbia Hills. Berry Class soil is also heavily altered (SO3 = 5 +/- 1 wt.% and Fe(3+)/Fe(sub T) = 0.60 +/- 0.13) and occurs at Meridiani Planum as lag deposits, at the crests of aeolian bedforms, and as isolated pockets on outcrop surfaces. Magnetite is identified as the strongly magnetic component in martian soil. Jarosite (in the Burns outcrop at Meridiani Planum) and goethite (in Clovis Class rocks at Gusev crater) are mineralogical markers for aqueous processes because they contain the hydroxide anion (OH(-)) as an essential part of their structure. Each yields approx.10 wt.% H2O upon dehydroxylation. The presence of Fe sulfates on opposite sides of Mars is evidence that aqueous processes under acid sulfate conditions are or were common. Except for Independence Class rocks in the Columbia Hills, the overall Fe mineralogical compositions and similar basaltic bulk chemical compositions (calculated with respect to S = Cl = 0) of the population of altered rocks analyzed by MER imply isochemical alteration of basaltic precursors at low water-to-rock ratios.

Surface alteration and physical properties of glass from the Cretaceous-Tertiary boundary

USGS Publications Warehouse

Barkatt, A.; Sang, J.C.; Thorpe, A.N.; Senftle, F.E.; Talmy, I.G.; Norr, M.K.; Mazer, J.J.; Izett, G.; Sigurdsson, Haraldur

1994-01-01

The scalloped surface feature on Cretaceous-Tertiary boundary glass is often explained as being due to terrestrial aqueous leaching. Leaching of man-made glass results in a reduction in density of the glass. Also, Fe, because of its relative insolubility, is concentrated by the leaching process. Thus, the Haitian glass specimens which have been heavily altered should have a thin rim of less dense glass in which the Fe is concentrated compared to the core glass. The higher Fe concentration in the rim glass should cause it to have an enhanced Curie constant and a lower density compared to the unaltered glass. The magnetic Curie constant, density, and scanning electron microscopic studies were made on altered specimens of Haitian glass and also on specimens showing a minimum of alteration. The results show that the less altered samples have the highest density and the lowest Curie constant. The data substantiate the terrestrial hypothesis. ?? 1994.

The Origin of Organic Matter in the Solar System: Evidence from Interplanetary Dust Particles

NASA Technical Reports Server (NTRS)

Flynn, G. J.; Keller, L. P.; Jacobsen, C.; Wirick, S.

2001-01-01

The origin of the organic matter in interplanetary materials has not been established. A variety of mechanisms have been proposed, with two extreme cases being a Fisher-Tropsch type process operating in the gas phase of the solar nebula or a Miller-Urey type process, which requires interaction with an aqueous fluid, presumably occurring on an asteroid. In the Fisher-Tropsch case, we might expect similar organic matter in hydrated and anhydrous interplanetary materials. However, aqueous alteration is required in the case of the Miller-Urey process, and we would expect to see organic matter preferentially in interplanetary materials that exhibit evidence of aqueous activity, such as the presence of hydrated silicates. The types and abundance of organic matter in meteorites have been used as an indicator of the origin of organic matter in the Solar System. Indigenous complex organic matter, including amino acids, has been found in hydrated carbonaceous chondrite meteorites, such as Murchison. Much lower amounts of complex organic matter, possibly only terrestrial contamination, have been found in anhydrous carbonaceous chondrite meteorites, such as Allende, that contain most of their carbon in elemental form. These results seem to favor production of the bulk of the organic matter in the Solar System by aqueous processing on parent bodies such as asteroids, a Miller-Urey process. However, the hydrated carbonaceous chondrite meteorites have approximately solar abundances of the moderately volatile elements, while all anhydrous carbonaceous chondrite meteorites have significantly lower contents of these moderately volatile elements. Two mechanisms, incomplete condensation or evaporation, both of which involve processing at approx. 1200 C, have been suggested to explain the lower content of the moderately volatile elements in all anhydrous meteorites. Additional information is contained in the original extended abstract.

The role of hydrothermal processes in the granite-hosted Zr, Y, REE deposit at Strange Lake, Quebec/Labrador: Evidence from fluid inclusions

NASA Astrophysics Data System (ADS)

Salvi, Stefano; Williams-Jones, Anthony E.

1990-09-01

The Strange Lake Zr, Y, REE, Nb, and Be deposit is hosted by a small, high-level, Late-Proterozoic peralkaline granite stock that intruded into high-grade metamorphic gneisses on the Quebec-Labrador border. The stock is extensively altered. Early alteration is manifested by the replacement of arfvedsonite with aegirine. Later alteration involved Ca-Na exchange. Zr, Ti, Y, REEs, Nb, and Be are concentrated in Ca-bearing minerals that, together with quartz, commonly pseudomorph Na-bearing minerals. Fluid inclusions in pseudomorphs comprise several distinct types: high-salinity (13 to 24 wt% NaCl eq.), Ca-rich aqueous inclusions that homogenize to liquid between 135 and 195°C; mixed aqueousmethane inclusions; methane inclusions; and solid-bearing inclusions. Aqueous-methane inclusions represent heterogeneous entrapment of immiscible high-salinity aqueous liquid and methane. Bastnäsite (tentatively identified by SEM analysis) occurs as a daughter mineral. Other daughter or trapped minerals include a Y, HREE-bearing mineral, possibly gagarinite, and hematite, galena, sphalerite, fluorite, pyrochlore, kutnahorite (?), and griceite (?). The first three inclusion types also occur in quartz in pegmatites and veins together with lower-temperature, lower-salinity, Na-dominated aqueous inclusions. The entrapment temperature inferred for the aqueous inclusions from microthermometry and the Na-K-Ca geothermometer range from 155 to 195°C for the higher-salinity inclusions and 100 to 165°C for the low-salinity inclusions. A model is proposed in which the intrusion of a peralkaline granite to high crustal levels initiated a ground/formational water-dominated hydrothermal system in adjacent gabbroic, calc-silicate, and graphitic gneisses. Reaction of the high-salinity, Ca-rich liquid with the graphitic gneisses led to the production of an immiscible methane gas. Subsequent interaction of this liquid with the granite led to extensive replacement of sodic minerals by calcium analogues at temperatures of less than 200°C. Some time after the onset of Ca metasomatism the high-salinity liquid mixed with a Ca-poor, low-salinity, low-temperature liquid that had leached F and rare metals from the granite. Yttrium and REE mineral deposition occurred as a result of the decreased ligand concentration that accompanied fluorite deposition during mixing of the Ca-rich and Ca-poor aqueous liquids.

Huygens Crater: Insights into Noachian Volcanism, Stratigraphy, and Aqueous Processes

NASA Technical Reports Server (NTRS)

Ackiss, S. E.; Wray, J. J.; Seelos, K. D.; Niles, P. B.

2015-01-01

Huygens crater is a well preserved peak ring structure on Mars centered at 13.5 deg S, 55.5 deg E in the Noachian highlands between Terras Tyrrhena and Sabaea near the NW rim of Hellas basin. With a diameter of approximately 470 km, it uplifted and exhumed pre-Noachian crustal materials from depths greater than 25 km, penetrating below the thick, ubiquitous layer of Hellas ejecta. In addition, Huygens served as a basin for subsequent aqueous activity, including erosion/deposition by fluvial valley networks and subsurface alteration that is now exposed by smaller impacts. Younger mafic-bearing plains that partially cover the basin floor and surrounding intercrater areas were likely emplaced by later volcanism.

Multiple stages of aqueous alteration along fractures in mudstone and sandstone strata in Gale Crater, Mars

NASA Astrophysics Data System (ADS)

Yen, A. S.; Ming, D. W.; Vaniman, D. T.; Gellert, R.; Blake, D. F.; Morris, R. V.; Morrison, S. M.; Bristow, T. F.; Chipera, S. J.; Edgett, K. S.; Treiman, A. H.; Clark, B. C.; Downs, R. T.; Farmer, J. D.; Grotzinger, J. P.; Rampe, E. B.; Schmidt, M. E.; Sutter, B.; Thompson, L. M.; MSL Science Team

2017-08-01

The Mars rover Curiosity in Gale crater conducted the first-ever direct chemical and mineralogical comparisons of samples that have clear parent (unaltered) and daughter (altered) relationships. The mineralogy and chemistry of samples within and adjacent to alteration halos in a sandstone formation were established by the Chemistry and Mineralogy (CheMin) X-ray diffraction (XRD) instrument and the Alpha Particle X-ray Spectrometer (APXS), respectively. The Stimson formation sandstones unconformably overlie the Murray mudstone formation and represent the youngest stratigraphic unit explored by Curiosity to date. Aqueous alteration of the parent sandstone resulted in a loss of half of the original crystalline mineral phases and a three-fold increase in X-ray amorphous material. Aqueous fluids extensively leached Mg, Al, Mn, Fe, Ni, Zn and other elements from the parent material, decreased the pyroxene to feldspar ratio by a factor of two, introduced Ca and mixed-cation sulfates, and both passively and actively enriched the silica content. Leaching of Mg, Al, Mn, Fe, Ni and Zn and enrichment of Si and S are also observed in alteration halos in the underlying mudstone. These observations are consistent with infiltration of subsurface fluids, initially acidic and then alkaline, propagating along fractures crosscutting the Stimson sandstone and Murray mudstone. The geochemistry and mineralogy suggest a complicated diagenetic history with multiple stages of aqueous alteration under a variety of environmental conditions (e.g. both low and moderate pH). The formation of these alteration halos post-dates lithification of the sandstones and mudstones and represents one of the youngest hydrogeologic events presently known to have occurred in Gale crater.

ESO Large Program on physical studies of Trans-Neptunian objects and Centaurs: Final results of the visible spectrophotometric observations

NASA Astrophysics Data System (ADS)

Fornasier, S.; Doressoundiram, A.; Tozzi, G. P.; Barucci, M. A.; Boehnhardt, H.; de Bergh, C.; Delsanti, A.; Davies, J.; Dotto, E.

2004-07-01

The Large Program on physical studies of TNOs and Centaurs, started at ESO Cerro Paranal on April 2001, has recently been concluded. This project was devoted to the investigation of the surface properties of these icy bodies through photometric and spectroscopic observations. In this paper we present the latest results on these pristine bodies obtained from the spectrophotometric investigation in the visible range. The newly obtained spectrophotometric data on 3 Centaurs and 5 TNOs, coming from 2 observing runs at the Very Large Telescope (VLT), show a large variety of spectral characteristics, comprising both gray and red objects in the two different populations. A very broad and weak absorption feature, centered around 7000 Å , has been revealed in the spectrum of the gray TNO 2003 AZ84. This absorption is very similar to a feature observed on low albedo main belt asteroids and attributed to the action of the aqueous alteration process on minerals. This process was previously also claimed as the most plausible explanation for some peculiar visible absorption bands observed on 2000 EB173 and 2000 GN171 in the framework of the Large Program (Lazzarin et al. \\cite{Lazzarin03}; de Bergh et al. \\cite{Bergh04}). This detection seems to reinforce the hypothesis that aqueous alteration might have taken place also at such large heliocentric distances. We also report the results of a spectroscopic investigation performed outside the Large Program on the very interesting TNO 2000 GN171 during part of its rotational period. This object, previously observed twice in the framework of the Large Program, had shown during the early observations a very peculiar absorption band tentatively attributed to aqueous alteration processes. As this feature was not confirmed in a successive spectrum, we recently repeated the investigations of 2000 GN171, finding out that it has an heterogeneous composition. Finally an analysis of the visible spectral slopes is reported for all the data coming from the Large Program and those available in literature. Based on observations obtained at the VLT Observatory Cerro Paranal of European Southern Observatory, ESO, Chile, in the framework of programs 167.C-0340(G), 071.C-0500.

Insights Into the Aqueous History of Mars from Acid-Sulfate Weathered Phyllosilicates

NASA Technical Reports Server (NTRS)

Craig, P. I.; Ming, D. W.; Rampe, E. B.; Morris, R. V.

2016-01-01

Phyllosilicates on Mars are thought to have formed during Mars' earliest Noachian geologic era (approx. 4.1-3.7 Ga). Sulfate formation, on the other hand, requires more acidic conditions which are thought to have occurred later during Mars' Hesperian era (approx. 3.7-3.0 Ga). Therefore, regions on Mars where phyllosilicates and sulfates are found in close proximity to each other provide evidence for the aqueous conditions during this global transition. Both phyllosilicates and sulfates form in the presence of water and thus give clues to the aqueous history of Mars and its potential for habitability. Phyllosilicates that formed during the Noachian era would have been weathered by the prevailing acidic conditions that define the Hesperian. Therefore, the purpose of this study is to characterize the alteration products of acid-sulfate weathered phyllosilicates in laboratory experiments, focusing on the Fe/Mg-smectites commonly identified on Mars. We also compare our results to observations of phyllosilicates and sulfates on Mars in regions such as Endeavour Crater and Mawrth Vallis to understand the formation process of sulfates and constrain the aqueous history of these regions.

Iron alteration minerals in the visible and near-infrared spectra of low-albedo asteroids

NASA Technical Reports Server (NTRS)

Vilas, Faith; Jarvis, Kandy S.; Gaffey, Michael J.

1994-01-01

Absorption features centered near 0.60-0.65 and 0.80-0.90 micrometers have been identified in the spectra of five low-albedo main-belt and outer-belt asteroids. These absorption features are attributed respectively to the (6)A(sub 1) goes to (4)T(sub 2)(G) and (6)A(sub 1) goes to (4)T(sub 1)(G) charge transfer transitions in minerals such as goethite, hematite, and jarosite that are products of the aqueous alteration of anhydrous silicates. A shoulder near 0.63 micrometers has also been identified in the absorption feature centered near 0.7 micrometers attributed to oxidized iron in phyllosilicates found predominantly in C- and G-class asteroids reflectance spectra. The coexistence of iron oxides with phyllosilicates in asteroids believed to have undergone aqueous alteration would be expected based upon analogy with terrestrial aqueous alteration and the observed mineralogy of carbonaceous chondrites. The number of low-albedo asteroids having only iron alteration absorption features compared to the number of low-albedo asteroids having spectral characteristics indicative of phyllosilicates is small. Either the conditions under which these asteroids formed are rare, or the iron alteration minerals could be formed in the interiors of objects where phyllosilicates dominate the surface mineralogy.

Lunar and Planetary Science XXXV: Organics and Alteration in Carbonaceous Chondrites: Goop and Crud

NASA Technical Reports Server (NTRS)

2004-01-01

The session "Organics and Alteration in Carbonaceous Chondrites: Goop and Crud" included the following reports:Organics on Fe-Silicate Grains: Potential Mimicry of Meteoritic Processes?; Molecular and Compound-Specific Isotopic Study of Monocarboxylic Acids in Murchison and Antarctic Meteorites; Nanoglobules, Macromolecular Materials, and Carbon Sulfides in Carbonaceous Chondrites; Evidence for Terrestrial Organic Contamination of the Tagish Lake Meteorite; Nitrogen Isotopic Imaging of Tagish Lake Carbon Globules; Microscale Distribution of Hydrogen Isotopes in Two Carbonaceous Chondrites; The Nature and Origin of Aromatic Organic Matter in the Tagish Lake Meteorite; Terrestrial Alteration of CM Chondritic Carbonate; Serpentine Nanotubes in CM Chondrites; Experimental Study of Serpentinization Reactions; Chondrule Glass Alteration in Type IIA Chondrules in the CR2 Chondrites EET 87770 and EET 92105: Insights into Elemental Exchange Between Chondrules and Matrices; Aqueous Alteration of Carbonaceous Chondrites: New Insights from Comparative Studies of Two Unbrecciated CM2 Chondrites, Y 791198 and ALH 81002 ;and A Unique Style of Alteration of Iron-Nickel Metal in WIS91600, an Unusual C2 Carbonaceous Chondrite.

Identification of hydrated silicate minerals on Mars using MRO-CRISM: Geologic context near Nili Fossae and implications for aqueous alteration

USGS Publications Warehouse

Ehlmann, B.L.; Mustard, J.F.; Swayze, G.A.; Clark, R.N.; Bishop, J.L.; Poulet, F.; Des Marais, D.J.; Roach, L.H.; Milliken, R.E.; Wray, J.J.; Barnouin-Jha, O.; Murchie, S.L.

2009-01-01

The Noachian terrain west of the Isidis basin hosts a diverse collection of alteration minerals in rocks comprising varied geomorphic units within a 100,000 km2 region in and near the Nili Fossae. Prior investigations in this region by the Observatoire pour l'Min??ralogie, l'Eau, les Glaces, et l'Activit?? (OMEGA) instrument on Mars Express revealed large exposures of both mafic minerals and iron magnesium phyllosilicates in stratigraphic context. Expanding on the discoveries of OMEGA, the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) aboard the Mars Reconnaissance Orbiter (MRO) has found more spatially widespread and mineralogically diverse alteration minerals than previously realized, which represent multiple aqueous environments. Using CRISM near-infrared spectral data, we detail the basis for identification of iron and magnesium smectites (including both nontronite and more Mg-rich varieties), chlorite, prehnite, serpentine, kaolinite, potassium mica (illite or muscovite), hydrated (opaline) silica, the sodium zeolite analcime, and magnesium carbonate. The detection of serpentine and analcime on Mars is reported here for the first time. We detail the geomorphic context of these minerals using data from high-resolution imagers onboard MRO in conjunction with CRISM. We find that the distribution of alteration minerals is not homogeneous; rather, they occur in provinces with distinctive assemblages of alteration minerals. Key findings are (1) a distinctive stratigraphy, in and around the Nili Fossae, of kaolinite and magnesium carbonate in bedrock units always overlying Fe/Mg smectites and (2) evidence for mineral phases and assemblages indicative of low-grade metamorphic or hydrothermal aqueous alteration in cratered terrains. The alteration minerals around the Nili Fossae are more typical of those resulting from neutral to alkaline conditions rather than acidic conditions, which appear to have dominated much of Mars. Moreover, the mineralogic diversity and geologic context of alteration minerals found in the region around the Nili Fossae indicates several episodes of aqueous activity in multiple distinct environments. Copyright 2009 by the American Geophysical Union.

The Spatial Distribution of Organic Matter and Mineralogical Relationships in Carbonaceous Chondrites

NASA Technical Reports Server (NTRS)

Clemett, S. J.; Messenger, S.; Thomas-Keprta, K. L.; Nakamura-Messenger, K.

2012-01-01

Organic matter present within primitive carbonaceous meteorites represents the complex conglomeration of species formed in a variety of physically and temporally distinct environments including circumstellar space, the interstellar medium, the Solar Nebula & Jovian sub-nebulae and asteroids. In each case, multiple chemical pathways would have been available for the synthesis of organic molecules. Consequently these meteorites constitute a unique record of organic chemical evolution in the Universe and one of the biggest challenges in organic cosmochemistry has been in deciphering this record. While bulk chemical analysis has provided a detailed description of the range and diversity of organic species present in carbonaceous chondrites, there is virtually no hard experimental data as to how these species are spatially distributed and their relationship to the host mineral matrix, (with one exception). The distribution of organic phases is nevertheless critical to understanding parent body processes. The CM and CI chondrites all display evidence of low temperature (< 350K) interaction with aqueous fluids, which based on O isotope data, flowed along thermal gradients within the respective parent bodies. This pervasive aqueous alteration may have led to aqueous geochromatographic separation of organics and synthesis of new organics coupled to aqueous mineral alteration. To address such issues we have applied the technique of microprobe two-step laser desorption / photoionization mass spectrometry (L2MS) to map in situ the spatial distribution of a broad range of organic species at the micron scale in the freshly exposed matrices of the Bells, Tagish Lake and Murchison (CM2) carbonaceous chondrites.

Phytotoxic effects of Sicyos deppei (Cucurbitaceae) in germinating tomato seeds.

PubMed

Lara-Núñez, Aurora; Sánchez-Nieto, Sobeida; Luisa Anaya, Ana; Cruz-Ortega, Rocio

2009-06-01

The phytotoxic effect of allelochemicals is referred to as allelochemical stress and it is considered a biotic stress. Sicyos deppei G. Don (Cucurbitaceae) is an allelopathic weed that causes phytotoxicity in Lycopersicon esculentum, delaying seed germination and severely inhibiting radicle growth. This paper reports in in vitro conditions, the effects of the aqueous leachate of S. deppei-throughout tomato germination times-on (1) the dynamics of starch and sugars metabolism, (2) activity and expression of the cell wall enzymes involved in endosperm weakening that allows the protrusion of the radicle, and (3) whether abscisic acid (ABA) is involved in this altered metabolic processes. Results showed that S. deppei leachate on tomato seed germination mainly caused: (1) delay in starch degradation as well as in sucrose hydrolysis; (2) lower activity of sucrose phosphate synthase, cell wall invertase, and alpha-amylase; being sucrose phosphate synthase (SPS) gene expression down-regulated, and the last two up regulated; (3) also, lower activity of endo beta-mannanase, beta-1,3 glucanase, alpha-galactosidase, and exo-polygalacturonase with altered gene expression; and (4) higher content of ABA during all times of germination. The phytotoxic effect of S. deppei aqueous leachate is because of the sum of many metabolic processes affected during tomato seed germination that finally is evidenced by a strong inhibition of radicle growth.

Nonlinear dynamics and instability of aqueous dissolution of silicate glasses and minerals

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

Wang, Yifeng; Jove-Colon, Carlos F.; Kuhlman, Kristopher L.

2016-07-22

Aqueous dissolution of silicate glasses and minerals plays a critical role in global biogeochemical cycles and climate evolution. The reactivity of these materials is also important to numerous engineering applications including nuclear waste disposal. The dissolution process has long been considered to be controlled by a leached surface layer in which cations in the silicate framework are gradually leached out and replaced by protons from the solution. This view has recently been challenged by observations of extremely sharp corrosion fronts and oscillatory zonings in altered rims of the materials, suggesting that corrosion of these materials may proceed directly through congruentmore » dissolution followed by secondary mineral precipitation. Here we show that complex silicate material dissolution behaviors can emerge from a simple positive feedback between dissolution-induced cation release and cation-enhanced dissolution kinetics. This self-accelerating mechanism enables a systematic prediction of the occurrence of sharp dissolution fronts (vs. leached surface layers), oscillatory dissolution behaviors and multiple stages of glass dissolution (in particular the alteration resumption at a late stage of a corrosion process). In conclusion, our work provides a new perspective for predicting long-term silicate weathering rates in actual geochemical systems and developing durable silicate materials for various engineering applications.« less

Water and the thermal evolution of carbonaceous chondrite parent bodies

NASA Technical Reports Server (NTRS)

Grimm, Robert E.; Mcsween, Harry Y., Jr.

1989-01-01

Two hypotheses are proposed for the aqueous alteration of carbonaceous chondrites within their parent bodies, in which respectively the alteration occurs (1) throughout the parent body interior, or (2) in a postaccretional surface regolith; both models assume an initially homogeneous mixture of ice and rock that is heated through the decay of Al-26. Water is seen to exert a powerful influence on chondrite evolution through its role of thermal buffer, permitting substitution of a low temperature aqueous alteration for high temperature recrystallization. It is quantitatively demonstrated that liquid water may be introduced by either hydrothermal circulation, vapor diffusion from below, or venting due to fracture.

Corona method and apparatus for altering carbon containing compounds

DOEpatents

Sharma, Amit K.; Camaioni, Donald M.; Josephson, Gary B.

1999-01-01

The present invention is a method and apparatus for altering a carbon containing compound in an aqueous mixture. According to a first aspect of the present invention, it has been discovered that for an aqueous mixture having a carbon containing compound with an ozone reaction rate less than the ozone reaction rate of pentachlorophenol, use of corona discharge in a low or non-oxidizing atmosphere increases the rate of destruction of the carbon containing compound compared to corona discharge an oxidizing atmosphere. For an aqueous mixture containing pentachlorphenol, there was essentially no difference in destruction between atmospheres. According to a second aspect of the present invention, it has been further discovered that an aqueous mixture having a carbon containing compound in the presence of a catalyst and oxygen resulted in an increased destruction rate of the carbon containing compound compared to no catalyst.

Corona Method And Apparatus For Altering Carbon Containing Compounds

DOEpatents

Sharma, Amit K.; Camaioni, Donald M.; Josephson; Gary B.

2004-05-04

The present invention is a method and apparatus for altering a carbon-containing compound in an aqueous mixture. According to a first aspect of the present invention, it has been discovered that for an aqueous mixture having a carbon containing compound with an ozone reaction rate less than the ozone reaction rate of pentachlorophenol, use of corona discharge in a low or non-oxidizing atmosphere increases the rate of destruction of the carbon containing compound compared to corona discharge an oxidizing atmosphere. For an aqueous mixture containing pentachlorphenol, there was essentially no difference in destruction between atmospheres. According to a second aspect of the present invention, it has been further discovered that an aqueous mixture having a carbon-containing compound in the presence of a catalyst and oxygen resulted in an increased destruction rate of the carbon containing compound compared to no catalyst.

Chondritic Asteroids--When Did Aqueous Alteration Happen?

NASA Astrophysics Data System (ADS)

Doyle, P. M.

2015-06-01

Using a synthesized fayalite (Fe2SiO4) standard for improved 53Mn-53Cr radiometric age dating, Patricia Doyle (previously at the University of Hawaii and now at the University of Cape Town, South Africa) and coauthors from Hawaii, the National Astronomical Observatory of Japan, University of Chicago, and Lawrence Livermore National Laboratory in California, analyzed aqueously formed fayalite in the ordinary chondrite Elephant Moraine 90161 (L3.05) and in the carbonaceous chondrites Asuka 881317 (CV3) and MacAlpine Hills 88107 (CO3-like) from Antarctica. The data obtained indicate that liquid water existed - and aqueous alteration started - on the chondritic parent bodies about three million years earlier than previously determined. This discovery has implications for understanding when and where the asteroids accreted. The 53Mn-53Cr chronology of chondrite aqueous alteration, combined with thermodynamic calculations and physical modeling, signifies that hydrated asteroids, at least those sampled by meteorites, accreted in the inner Solar System (2-4 AU) near the main asteroid belt 2-4 million years after the beginning of the Solar System, rather than migrating inward after forming in the Solar System's colder, outer regions beyond Jupiter's present orbit (5-15 AU).

The amino acid and hydrocarbon contents of the Paris meteorite, the most primitive CM chondrite

NASA Astrophysics Data System (ADS)

Martins, Zita; Modica, Paola; Zanda, Brigitte; Le Sergeant d'Hendecourt, Louis

2015-04-01

The Paris meteorite is reported to be the least aqueously altered CM chondrite [1,2], and to have experienced only weak thermal metamorphism [2-5]. The IR spectra of some of Paris' fragments suggest a primitive origin for the organic matter in this meteorite, similar to the spectra from solid-state materials in molecular clouds [6]. Most of the micron-sized organic particles present in the Paris matrix exhibit 0 < δD <2000‰ [7,8]. In order to understand the effect of aqueous alteration and thermal metamorphism on the abundance and distribution of meteoritic soluble organic matter, we have analyzed for the first time the amino acid and hydrocarbon contents of the Paris meteorite [9]. Extensive aqueous alteration in the parent body of carbonaceous meteorites may result in the decomposition of α-amino acids and the synthesis of β- and γ-amino acids. When plotted with several CM chondrites, Paris has the lowest relative abundance of β-alanine/glycine (0.15) for a CM chondrite, which fits with the relative abundance of β-alanine/glycine increasing with increasing aqueous alteration [10,11]. In addition, our results show that the isovaline detected in this meteorite is racemic (D/L= 0.99 ± 0.08; L-enantiomer excess (%) = 0.35 ± 0.5; corrected D/L = 1.03; corrected L-enantiomer excess (%) = -1.4 ± 2.6). Although aqueous alteration does not create by itself an isovaline asymmetry, it may amplify a small enantiomeric excess. Therefore, our data may support the hypothesis that aqueous alteration is responsible for the high L-enantiomer excess of isovaline observed in the most aqueously altered carbonaceous meteorites [12,13]. Paris has n-alkanes ranging from C16 to C25 and 3- to 5-ring non-alkylated polycyclic aromatic hydrocarbons (PAHs). The lack of alkylated PAHs in Paris seems to be related to the low degree of aqueous alteration on its parent body [9,14]. The extra-terrestrial aliphatic and aromatic hydrocarbon content of Paris may have an interstellar origin or contribution from interstellar precursors. In summary, the soluble organic content of the primitive CM chondrite Paris possibly relates to late phases of condensed phase chemistry in molecular clouds. References: [1] Blanchard et al. (2011) Abstract #5322. Meteoritics and Planetary Science 46:A21. [2] Caillet Komorowski et al. (2011) Abstract #5289. Meteoritics and Planetary Science 46:A35. [3] Kimura et al. (2011) Meteoritics & Planetary Science 46:431-442. [4] Bourot-Denise et al. (2010) Abstract #1533. 41st LPSC. CD-ROM. [5] Merouane et al. (2011) Proceedings, EPSC-DPS Joint Meeting, pp.902. [6] Merouane et al. (2012) The Astrophysical Journal 756:154-160. [7] Remusat et al. (2010) The Astrophysical Journal 713:1048-1058. [8] Remusat et al. (2011) Abstract #5327. Meteoritics and Planetary Science 46:A197. [9] Martins et al. Meteoritics and Planetary Science, under review. [10] Glavin et al. (2006) Meteoritics & Planetary Science 41:889-902. [11] Glavin et al. (2010) Abstract #5131. Meteoritics and Planetary Science 45:A64. [12] Pizzarello et al. (2003) GCA 67:1589-1595. [13] Glavin and Dworkin (2009) PNAS 106:5487-5492. [14] Elsila et al. (2005) GCA 69:1349-1357.

Effects of Precursor Concentration and Acidic Sulfate in Aqueous Glyoxal−OH Radical Oxidation and Implications for Secondary Organic Aerosol

PubMed Central

2009-01-01

Previous experiments demonstrated that aqueous OH radical oxidation of glyoxal yields low-volatility compounds. When this chemistry takes place in clouds and fogs, followed by droplet evaporation (or if it occurs in aerosol water), the products are expected to remain partially in the particle phase, forming secondary organic aerosol (SOA). Acidic sulfate exists ubiquitously in atmospheric water and has been shown to enhance SOA formation through aerosol phase reactions. In this work, we investigate how starting concentrations of glyoxal (30−3000 μM) and the presence of acidic sulfate (0−840 μM) affect product formation in the aqueous reaction between glyoxal and OH radical. The oxalic acid yield decreased with increasing precursor concentrations, and the presence of sulfuric acid did not alter oxalic acid concentrations significantly. A dilute aqueous chemistry model successfully reproduced oxalic acid concentrations, when the experiment was performed at cloud-relevant concentrations (glyoxal <300 μM), but predictions deviated from measurements at increasing concentrations. Results elucidate similarities and differences in aqueous glyoxal chemistry in clouds and in wet aerosols. They validate for the first time the accuracy of model predictions at cloud-relevant concentrations. These results suggest that cloud processing of glyoxal could be an important source of SOA. PMID:19924930

Embryonic exposure to an aqueous coal dust extract results in gene expression alterations associated with the development and function of connective tissue and the hematological system, immunological and inflammatory disease, and cancer in zebrafish.

PubMed

Caballero-Gallardo, Karina; Wirbisky-Hershberger, Sara E; Olivero-Verbel, Jesus; de la Rosa, Jesus; Freeman, Jennifer L

2018-03-01

Coal mining is one of the economic activities with the greatest impact on environmental quality. At all stages contaminants are released as particulates such as coal dust. The first aim of this study was to obtain an aqueous coal dust extract and characterize its composition in terms of trace elements by ICP-MS. In addition, the developmental toxicity of the aqueous coal extract was evaluated using zebrafish (Danio rerio) after exposure to different concentrations (0-1000 ppm; μg mL -1 ) to establish acute toxicity, morphology and transcriptome changes. Trace elements within the aqueous coal dust extract present at the highest concentrations (>10 ppb) included Sr, Zn, Ba, As, Cu and Se. In addition, Cd and Pb were found in lower concentrations. No significant difference in mortality was observed (p > 0.05), but a delay in hatching was found at 0.1 and 1000 ppm (p < 0.05). No significant differences in morphological characteristics were observed in any of the treatment groups (p > 0.05). Transcriptomic results of zebrafish larvae revealed alterations in 77, 61 and 1376 genes in the 1, 10, and 100 ppm groups, respectively. Gene ontology analysis identified gene alterations associated with the development and function of connective tissue and the hematological system, as well as pathways associated with apoptosis, the cell cycle, transcription, and oxidative stress including the MAPK signaling pathway. In addition, altered genes were associated with cancer; connective tissue, muscular, and skeletal disorders; and immunological and inflammatory diseases. Overall, this is the first study to characterize gene expression alterations in response to developmental exposure to aqueous coal dust residue from coal mining with transcriptome results signifying functions and systems to target in future studies.

Primordial and cosmogenic noble gases in the Sutter's Mill CM chondrite

NASA Astrophysics Data System (ADS)

Okazaki, Ryuji; Nagao, Keisuke

2017-04-01

The Sutter's Mill (SM) CM chondrite fell in California in 2012. The CM chondrite group is one of the most primitive, consisting of unequilibrated minerals, but some of them have experienced complex processes occurring on their parent body, such as aqueous alteration, thermal metamorphism, brecciation, and solar wind implantation. We have determined noble gas concentrations and isotopic compositions for SM samples using a stepped heating gas extraction method, in addition to mineralogical observation of the specimens. The primordial noble gas abundances, especially the P3 component trapped in presolar diamonds, confirm the classification of SM as a CM chondrite. The mineralogical features of SM indicate that it experienced mild thermal alteration after aqueous alteration. The heating temperature is estimated to be <350 °C based on the release profile of primordial 36Ar. The presence of a Ni-rich Fe-Ni metal suggests that a minor part of SM has experienced heating at >500 °C. The variation in the heating temperature of thermal alteration is consistent with the texture as a breccia. The heterogeneous distribution of solar wind noble gases is also consistent with it. The cosmic-ray exposure (CRE) age for SM is calculated to be 0.059 ± 0.023 Myr based on cosmogenic 21Ne by considering trapped noble gases as solar wind, the terrestrial atmosphere, P1 (or Q), P3, A2, and G components. The CRE age lies at the shorter end of the CRE age distribution of the CM chondrite group.

On the in situ aqueous alteration of soils on Mars

USGS Publications Warehouse

Amundson, Ronald; Ewing, S.; Dietrich, W.; Sutter, B.; Owen, J.; Chadwick, O.; Nishiizumi, K.; Walvoord, Michelle Ann; McKay, C.

2008-01-01

Early (>3 Gy) wetter climate conditions on Mars have been proposed, and it is thus likely that pedogenic processes have occurred there at some point in the past. Soil and rock chemistry of the Martian landing sites were evaluated to test the hypothesis that in situ aqueous alteration and downward movement of solutes have been among the processes that have transformed these portions of the Mars regolith. A geochemical mass balance shows that Martian soils at three landing sites have lost significant quantities of major rock-forming elements and have gained elements that are likely present as soluble ions. The loss of elements is interpreted to have occurred during an earlier stage(s) of weathering that may have been accompanied by the downward transport of weathering products, and the salts are interpreted to be emplaced later in a drier Mars history. Chemical differences exist among the sites, indicating regional differences in soil composition. Shallow soil profile excavations at Gusev crater are consistent with late stage downward migration of salts, implying the presence of small amounts of liquid water even in relatively recent Martian history. While the mechanisms for chemical weathering and salt additions on Mars remain unclear, the soil chemistry appears to record a decline in leaching efficiency. A deep sedimentary exposure at Endurance crater contains complex depth profiles of SO4, Cl, and Br, trends generally consistent with downward aqueous transport accompanied by drying. While no model for the origin of Martian soils can be fully constrained with the currently available data, a pedogenic origin is consistent with observed Martian geology and geochemistry, and provides a testable hypothesis that can be evaluated with present and future data from the Mars surface. ?? 2008 Elsevier Ltd.

CR chondrites: Shock, aqueous alteration and terrestrial weathering

NASA Astrophysics Data System (ADS)

Abreu, N. M.

2012-12-01

CR chondrite are a group asteroidal meteorites, whose importance lies in the exotic organic and presolar material [1] found in its most pristine members and in the broad range of alteration features represented in the remaining specimens in this group [2]. This FE-SEM, EMPA, FIB/TEM study takes advantage of the CR's mineralogical diversity to define different trends of secondary alteration, by comparing the CR3s to the Antarctic CRs: MIL 07525, MIL 07513, GRA 06100, LAP 04516, GRO 03116, GRO 95577, and EET 96259. Collisions and subsequent annealing have affected MIL 07513, GRA 06100, and GRO 03116. Shock stages are often assigned based on progressive changes in the textures of olivines and feldspars. However, the large olivines in shocked CRs do not appear to record these process. Opaques, on the other hand, preserve hallmark signatures of impacts, such as crystalline metal/sulfide veins. Opaque nodules in MIL 07513, GRA 06100, GRO 03116 consist of intergrowths of μm-sub μm FeNi-rich metal, kamacite, Fe-sulfides, Fe-oxides, nm-sized metallic Cu and CuFe (~85 wt.% Cu, 14 wt.% Fe ± < 1wt.% Co, Ni, S) alloys. MIL 07525, GRO 03116, EET 96259, LAP 04516, and GRO 95577 show increasing signs of aqueous alteration, such as increasing amounts of ordered phyllosilicates. Although most phyllosilicates are intergrowths of Fe-rich serpentine and saponite, LAP 04516 also contains large (μm-sized), interpenetrating, Fe-rich (cronstedtite-like) phyllosilicates packages with 14Å basal spacings, similar to those observed in CI chondrites by [3]. Heterogeneously interspersed within phyllosilicates are amorphous Fe-rich silicates and small grains (<50nm) of Fe-rich sulfides, partly oxidized sulfides, and in LAP 04516, tochilinite. Tochilinite shows consistent enrichments in Si (~5 wt.%), suggesting that this meteorite has undergone similar pathways of aqueous alteration as CM chondrites [e.g., 4-5]. Despite the myriad of mineralogical changes triggered by secondary and tertiary process affecting the CRs, the relationship between the average S and Fe contents of matrices are good indicators of the alteration histories of these chondrites. The average S versus Fe contents of CR matrices follow a roughly linear trend. The most aqueously altered CRs (e.g., LAP 04516) have the lowest Fe and the highest S content. The matrices in shocked CRs, MIL 07513, GRA 06100, GRO 03116, have the lowest S content of the studied CRs. They are also the most Fe-rich. The CR3 chondrites fall somewhere in the middle of the S vs. Fe plot. Terrestrial weathering creates some scattering due to its contribution to the Fe-content of the matrix. If the precursor materials of the shocked CRs composi-tionally resemble CR3 chondrites, low S content of shocked CR matrices probably resulted from volatile losses driven by shock and annealing. Whereas increasing Fe-contents are probably linked to impact-driven hydrothermal mobilization of Fe from kamacite nodules. References: [1] Floss et al. 2009. Ap. J. 697: 1242-1255. [2] Abreu N. M. 2007. [3] Tomeoka K. & Buseck P. R. 1988. GCA 52: 1627-1640. [4] Tomeoka K. & Buseck P. R. 1985. GCA 49: 21-49-2163. [5] Rubin A. et al. 2007. GCA 71: 2361-2382. Acknowledgements: Funded by NNX11AH10G grant and conducted at Penn State and ARES-JSC. Meteorite kindly pro-vided by the JSC Antarctic meteorite curators.

In situ isotopic studies of the U-depleted Allende CAI Curious Marie: Pre-accretionary alteration and the co-existence of 26Al and 36Cl in the early solar nebula

NASA Astrophysics Data System (ADS)

Tang, Haolan; Liu, Ming-Chang; McKeegan, Kevin D.; Tissot, Francois L. H.; Dauphas, Nicolas

2017-06-01

The isotopic composition of oxygen as well as 26Al-26Mg and 36Cl-36S systematics were studied in Curious Marie, an aqueously altered Allende CAI characterized by a Group II REE pattern and a large 235U excess produced by the decay of short-lived 247Cm. Oxygen isotopic compositions in the secondary minerals of Curious Marie follow a mass-dependent fractionation line with a relatively homogenous depletion in 16O (Δ17O of -8‰) compared to unaltered minerals of CAI components. Both Mg and S show large excesses of radiogenic isotopes (26Mg∗ and 36S∗) that are uniformly distributed within the CAI, independent of parent/daughter ratio. A model initial 26Al/27Al ratio [(6.2 ± 0.9) × 10-5], calculated using the bulk Al/Mg ratio and the uniform δ26Mg∗ ∼ +43‰, is similar to the canonical initial solar system value within error. The exceptionally high bulk Al/Mg ratio of this CAI (∼95) compared to other inclusions is presumably due to Mg mobilization by fluids. Therefore, the model initial 26Al/27Al ratio of this CAI implies not only the early condensation of the CAI precursor but also that aqueous alteration occurred early, when 26Al was still at or near the canonical value. This alteration event is most likely responsible for the U depletion in Curious Marie and occurred at most 50 kyr after CAI formation, leading to a revised estimate of the early solar system 247Cm/235U ratio of (5.6 ± 0.3) × 10-5. The Mg isotopic composition in Curious Marie was subsequently homogenized by closed-system thermal processing without contamination by chondritic Mg. The large, homogeneous 36S excesses (Δ36S∗ ∼ +97‰) detected in the secondary phases of Curious Marie are attributed to 36Cl decay (t1/2 = 0.3 Myr) that was introduced by Cl-rich fluids during the aqueous alteration event that led to sodalite formation. A model 36Cl/35Cl ratio of (2.3 ± 0.6) × 10-5 is calculated at the time of aqueous alteration, translating into an initial 36Cl/35Cl ratio of ∼1.7-3 × 10-5 at solar system birth. The Mg and S radiogenic excesses suggest that 26Al and 36Cl co-existed in the early solar nebula, raising the possibility that, in addition to an irradiation origin, 36Cl could have also been derived from a stellar source.

Characterizing the Phyllosilicates and Amorphous Phases Found by MSL Using Laboratory XRD and EGA Measurements of Natural and Synthetic Materials

NASA Technical Reports Server (NTRS)

Rampe, Elizabeth B.; Morris, Richard V.; Chipera, Steve; Bish, David L.; Bristow, Thomas; Archer, Paul Douglas; Blake, David; Achilles, Cherie; Ming, Douglas W.; Vaniman, David;

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

Jun, Young -Shin; Kim, Doyoon; Neil, Chelsea W.

Here, mineral nucleation is a phase transformation of aqueous components to solids with an accompanying creation of new surfaces. In this evolutional, yet elusive, process, nuclei often form at environmental interfaces, which provide remarkably reactive sites for heterogeneous nucleation and growth. Naturally occurring nucleation processes significantly contribute to the biogeochemical cycles of important components in the Earth’s crust, such as iron and manganese oxide minerals and calcium carbonate. However, in recent decades, these cycles have been significantly altered by anthropogenic activities, which affect the aqueous chemistry and equilibrium of both surface and subsurface systems. These alterations can trigger the dissolutionmore » of existing minerals and formation of new nanoparticles (i.e., nucleation and growth) and consequently change the porosity and permeability of geomedia in subsurface environments. Newly formed nanoparticles can also actively interact with components in natural and engineered aquatic systems, including those posing a significant hazard such as arsenic. These interactions can bilaterally influence the fate and transport of both newly formed nanoparticles and aqueous components. Due to their importance in natural and engineered processes, heterogeneous nucleation at environmental interfaces has started to receive more attention. However, a lack of time-resolved in situ analyses makes the evaluation of heterogeneous nucleation challenging because the physicochemical properties of both the nuclei and surfaces significantly and dynamically change with time and aqueous chemistry. This Account reviews our in situ kinetic studies of the heterogeneous nucleation and growth behaviors of iron(III) (hydr)oxide, calcium carbonate, and manganese (hydr)oxide minerals in aqueous systems. In particular, we utilized simultaneous small-angle and grazing incidence small-angle X-ray scattering (SAXS/GISAXS) to investigate in situ and in real-time the effects of water chemistry and substrate identity on heterogeneously and homogeneously formed nanoscale precipitate size dimensions and total particle volume. Using this technique, we also provided a new platform for quantitatively comparing between heterogeneous and homogeneous nucleation and growth of nanoparticles and obtaining undiscovered interfacial energies between nuclei and surfaces. In addition, nanoscale surface characterization tools, such as in situ atomic force microscopy (AFM), were utilized to support and complement our findings. With these powerful nanoscale tools, we systematically evaluated the influences of environmentally abundant (oxy)anions and cations and the properties of environmental surfaces, such as surface charge and hydrophobicity. The findings, significantly enhanced by in situ observations, can lead to a more accurate prediction of the behaviors of nanoparticles in the environment and enable better control of the physicochemical properties of nanoparticles in engineered systems, such as catalytic reactions and energy storage.« less

Heterogeneous nucleation and growth of nanoparticles at environmental interfaces

DOE PAGES

Jun, Young -Shin; Kim, Doyoon; Neil, Chelsea W.

2016-08-11

Here, mineral nucleation is a phase transformation of aqueous components to solids with an accompanying creation of new surfaces. In this evolutional, yet elusive, process, nuclei often form at environmental interfaces, which provide remarkably reactive sites for heterogeneous nucleation and growth. Naturally occurring nucleation processes significantly contribute to the biogeochemical cycles of important components in the Earth’s crust, such as iron and manganese oxide minerals and calcium carbonate. However, in recent decades, these cycles have been significantly altered by anthropogenic activities, which affect the aqueous chemistry and equilibrium of both surface and subsurface systems. These alterations can trigger the dissolutionmore » of existing minerals and formation of new nanoparticles (i.e., nucleation and growth) and consequently change the porosity and permeability of geomedia in subsurface environments. Newly formed nanoparticles can also actively interact with components in natural and engineered aquatic systems, including those posing a significant hazard such as arsenic. These interactions can bilaterally influence the fate and transport of both newly formed nanoparticles and aqueous components. Due to their importance in natural and engineered processes, heterogeneous nucleation at environmental interfaces has started to receive more attention. However, a lack of time-resolved in situ analyses makes the evaluation of heterogeneous nucleation challenging because the physicochemical properties of both the nuclei and surfaces significantly and dynamically change with time and aqueous chemistry. This Account reviews our in situ kinetic studies of the heterogeneous nucleation and growth behaviors of iron(III) (hydr)oxide, calcium carbonate, and manganese (hydr)oxide minerals in aqueous systems. In particular, we utilized simultaneous small-angle and grazing incidence small-angle X-ray scattering (SAXS/GISAXS) to investigate in situ and in real-time the effects of water chemistry and substrate identity on heterogeneously and homogeneously formed nanoscale precipitate size dimensions and total particle volume. Using this technique, we also provided a new platform for quantitatively comparing between heterogeneous and homogeneous nucleation and growth of nanoparticles and obtaining undiscovered interfacial energies between nuclei and surfaces. In addition, nanoscale surface characterization tools, such as in situ atomic force microscopy (AFM), were utilized to support and complement our findings. With these powerful nanoscale tools, we systematically evaluated the influences of environmentally abundant (oxy)anions and cations and the properties of environmental surfaces, such as surface charge and hydrophobicity. The findings, significantly enhanced by in situ observations, can lead to a more accurate prediction of the behaviors of nanoparticles in the environment and enable better control of the physicochemical properties of nanoparticles in engineered systems, such as catalytic reactions and energy storage.« less

Heterogeneous Nucleation and Growth of Nanoparticles at Environmental Interfaces.

PubMed

Jun, Young-Shin; Kim, Doyoon; Neil, Chelsea W

2016-09-20

Mineral nucleation is a phase transformation of aqueous components to solids with an accompanying creation of new surfaces. In this evolutional, yet elusive, process, nuclei often form at environmental interfaces, which provide remarkably reactive sites for heterogeneous nucleation and growth. Naturally occurring nucleation processes significantly contribute to the biogeochemical cycles of important components in the Earth's crust, such as iron and manganese oxide minerals and calcium carbonate. However, in recent decades, these cycles have been significantly altered by anthropogenic activities, which affect the aqueous chemistry and equilibrium of both surface and subsurface systems. These alterations can trigger the dissolution of existing minerals and formation of new nanoparticles (i.e., nucleation and growth) and consequently change the porosity and permeability of geomedia in subsurface environments. Newly formed nanoparticles can also actively interact with components in natural and engineered aquatic systems, including those posing a significant hazard such as arsenic. These interactions can bilaterally influence the fate and transport of both newly formed nanoparticles and aqueous components. Due to their importance in natural and engineered processes, heterogeneous nucleation at environmental interfaces has started to receive more attention. However, a lack of time-resolved in situ analyses makes the evaluation of heterogeneous nucleation challenging because the physicochemical properties of both the nuclei and surfaces significantly and dynamically change with time and aqueous chemistry. This Account reviews our in situ kinetic studies of the heterogeneous nucleation and growth behaviors of iron(III) (hydr)oxide, calcium carbonate, and manganese (hydr)oxide minerals in aqueous systems. In particular, we utilized simultaneous small-angle and grazing incidence small-angle X-ray scattering (SAXS/GISAXS) to investigate in situ and in real-time the effects of water chemistry and substrate identity on heterogeneously and homogeneously formed nanoscale precipitate size dimensions and total particle volume. Using this technique, we also provided a new platform for quantitatively comparing between heterogeneous and homogeneous nucleation and growth of nanoparticles and obtaining undiscovered interfacial energies between nuclei and surfaces. In addition, nanoscale surface characterization tools, such as in situ atomic force microscopy (AFM), were utilized to support and complement our findings. With these powerful nanoscale tools, we systematically evaluated the influences of environmentally abundant (oxy)anions and cations and the properties of environmental surfaces, such as surface charge and hydrophobicity. The findings, significantly enhanced by in situ observations, can lead to a more accurate prediction of the behaviors of nanoparticles in the environment and enable better control of the physicochemical properties of nanoparticles in engineered systems, such as catalytic reactions and energy storage.

Sulfate Mineral Formation from Acid-Weathered Phyllosilicates: Implications for the Aqueous History of Mars

NASA Technical Reports Server (NTRS)

Craig, P. I.; Ming, D. W.; Rampe, E. B.; Morris, R. V.

2015-01-01

Phyllosilicates on Mars are thought to have formed under neutral to alkaline conditions during Mars' earliest Noachian geologic era (approx. 4.1-3.7 Gya). Sulfate formation, on the other hand, requires more acidic conditions which are thought to have occurred later during Mars' Hesperian era (approx. 3.7-3.0 Gya). Therefore, regions on Mars where phyllosilicates and sulfates are found in close proximity to each other provide evidence for the geologic and aqueous conditions during this global transition. Both phyllosilicates and sulfates form in the presence of water and thus give clues to the aqueous history of Mars and its potential for habitability. Phyllosilicates that formed during the Noachian era may have been weathered by the prevailing acidic conditions that characterize the Hesperian. Therefore, the purpose of this study is to characterize the alteration products resulting from acid-sulfate weathered phyllosilicates in laboratory experiments. This study focuses on two phyllosilicates commonly identified with sulfates on Mars: nontronite and saponite. We also compare our results to observations of phyllosilicates and sulfates on Mars to better understand the formation process of sulfates in close proximity to phyllosilicates on Mars and constrain the aqueous conditions of these regions on Mars.

Strengthening of the Coordination Shell by Counter Ions in Aqueous Th 4+ Solutions

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

Atta-Fynn, Raymond; Bylaska, Eric J.; de Jong, Wibe A.

The presence of counter ions in solutions containing highly charged metal cations can trigger processes such as ion-pair formation, hydrogen bond breakages and subsequent reformation, and ligand exchanges. In this work, it is shown how halide (Cl-, Br-) and perchlorate (ClO4-) anions affect the strength of the primary solvent coordination shells around Th4+ using explicit solvent and finite temperature ab initio molecular dynamics modeling methods. The 9-fold solvent geometry was found to be the most stable hydration structure in each aqueous solution. Relative to the dilute aqueous solution, the presence of the counter ions did not significantly alter the geometrymore » of the primary hydration shell. However, the free energy analyses indicated that the 10-fold hydrated states were thermodynamically accessible in dilute and bromide aqueous solutions within 1 kcal/mol. Analysis of the results showed that the hydrogen bond lifetimes were longer and solvent exchange energy barriers were larger in solutions with counter ions in comparison with the solution with no counter ions. This implies that the presence of the counter ions induces a strengthening of the Th4+ hydration shell.« less

Stability of peptides in high-temperature aqueous solutions

NASA Astrophysics Data System (ADS)

Shock, Everett L.

1992-09-01

Estimated standard molal thermodynamic properties of aqueous dipeptides and their constituent amino acids indicate that temperature increases correspond to increased stability of peptide bonds relative to hydrolysis reactions. Pressure increases cause slight decreases in peptide bond stability, which are generally offset by greater stability caused by temperature increases along geothermal gradients. These calculations suggest that peptides, polypeptides, and proteins may survive hydrothermal alteration of organic matter depending on the rates of the hydrolysis reactions. Extremely thermophilic organisms may be able to take advantage of the decreased energy required to form peptide bonds in order to maintain structural proteins and enzymes at elevated temperatures and pressures. As the rates of hydrolysis reactions increase with increasing temperature, formation of peptide bonds may become a facile process in hydrothermal systems and deep in sedimentary basins.

Iron mineralogy and aqueous alteration from Husband Hill through Home Plate at Gusev Crater, Mars: Results from the Mössbauer instrument on the Spirit Mars Exploration Rover

NASA Astrophysics Data System (ADS)

Morris, R. V.; Klingelhöfer, G.; Schröder, C.; Fleischer, I.; Ming, D. W.; Yen, A. S.; Gellert, R.; Arvidson, R. E.; Rodionov, D. S.; Crumpler, L. S.; Clark, B. C.; Cohen, B. A.; McCoy, T. J.; Mittlefehldt, D. W.; Schmidt, M. E.; de Souza, P. A.; Squyres, S. W.

2008-12-01

Spirit's Mössbauer (MB) instrument determined the Fe mineralogy and oxidation state of 71 rocks and 43 soils during its exploration of the Gusev plains and the Columbia Hills (West Spur, Husband Hill, Haskin Ridge, northern Inner Basin, and Home Plate) on Mars. The plains are predominantly float rocks and soil derived from olivine basalts. Outcrops at West Spur and on Husband Hill have experienced pervasive aqueous alteration as indicated by the presence of goethite. Olivine-rich outcrops in a possible mafic/ultramafic horizon are present on Haskin Ridge. Relatively unaltered basalt and olivine basalt float rocks occur at isolated locations throughout the Columbia Hills. Basalt and olivine basalt outcrops are found at and near Home Plate, a putative hydrovolcanic structure. At least three pyroxene compositions are indicated by MB data. MB spectra of outcrops Barnhill and Torquas resemble palagonitic material and thus possible supergene aqueous alteration. Deposits of Fe3+-sulfate soil, located at Paso Robles, Arad, and Tyrone, are likely products of acid sulfate fumarolic and/or hydrothermal activity, possibly in connection with Home Plate volcanism. Hematite-rich outcrops between Home Plate and Tyrone (e.g., Montalva) may also be products of this aqueous activity. Low water-to-rock ratios (isochemical alteration) are implied during palagonite, goethite, and hematite formation because bulk chemical compositions are basaltic (SO3-free basis). High water-to-rock ratios (leaching) under acid sulfate conditions are implied for the high-SiO2 rock and soil in Eastern Valley and the float rock FuzzySmith, which has possible pyrite/marcasite as a hydrothermal alteration product.

The use of positrons to survey alteration layers on synthetic nuclear waste glasses

NASA Astrophysics Data System (ADS)

Reiser, Joelle T.; Parruzot, Benjamin; Weber, Marc H.; Ryan, Joseph V.; McCloy, John S.; Wall, Nathalie A.

2017-07-01

In order to safeguard society and the environment, understanding radioactive waste glass alteration mechanisms in interactions with solutions and near-field materials, such as Fe, is essential to nuclear waste repository performance assessments. Alteration products are formed at the surface of glasses after reaction with solution. In this study, glass altered in the presence of Fe0 in aqueous solution formed two alteration layers: one embedded with Fe closer to the surface and one without Fe found deeper in the sample. Both layers were found to be thinner than the alteration layer found in glass altered in aqueous solution only. For the first time, Doppler Broadening Positron Annihilation Spectroscopy (DB-PAS) is used to non-destructively characterize the pore structures of glass altered in the presence of Fe0. Advantages and disadvantages of DB-PAS compared to other techniques used to analyze pore structures for altered glass samples are discussed. Ultimately, DB-PAS has shown to be an excellent choice for pore structure characterization for glasses with multiple alteration layers. Monte Carlo modeling predicted positron trajectories through the layers, and helped explain DB-PAS data, which showed that the deeper alteration layer without Fe had a similar composition and pore structure to layers on glass altered in water only.

The use of positrons to survey alteration layers on synthetic nuclear waste glasses

DOE PAGES

Reiser, Joelle T.; Parruzot, Benjamin; Weber, Marc H.; ...

2017-07-01

Here, in order to safeguard society and the environment, understanding radioactive waste glass alteration mechanisms in interactions with solutions and near-field materials, such as Fe, is essential to nuclear waste repository performance assessments. Alteration products are formed at the surface of glasses after reaction with solution. In this study, glass altered in the presence of Fe 0 in aqueous solution formed two alteration layers: one embedded with Fe closer to the surface and one without Fe found deeper in the sample. Both layers were found to be thinner than the alteration layer found in glass altered in aqueous solution only.more » For the first time, Doppler Broadening Positron Annihilation Spectroscopy (DB-PAS) is used to non-destructively characterize the pore structures of glass altered in the presence of Fe 0. Advantages and disadvantages of DB-PAS compared to other techniques used to analyze pore structures for altered glass samples are discussed. Ultimately, DB-PAS has shown to be an excellent choice for pore structure characterization for glasses with multiple alteration layers. Monte Carlo modeling predicted positron trajectories through the layers, and helped explain DB-PAS data, which showed that the deeper alteration layer without Fe had a similar composition and pore structure to layers on glass altered in water only.« less

The use of positrons to survey alteration layers on synthetic nuclear waste glasses

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

Reiser, Joelle T.; Parruzot, Benjamin; Weber, Marc H.

Here, in order to safeguard society and the environment, understanding radioactive waste glass alteration mechanisms in interactions with solutions and near-field materials, such as Fe, is essential to nuclear waste repository performance assessments. Alteration products are formed at the surface of glasses after reaction with solution. In this study, glass altered in the presence of Fe 0 in aqueous solution formed two alteration layers: one embedded with Fe closer to the surface and one without Fe found deeper in the sample. Both layers were found to be thinner than the alteration layer found in glass altered in aqueous solution only.more » For the first time, Doppler Broadening Positron Annihilation Spectroscopy (DB-PAS) is used to non-destructively characterize the pore structures of glass altered in the presence of Fe 0. Advantages and disadvantages of DB-PAS compared to other techniques used to analyze pore structures for altered glass samples are discussed. Ultimately, DB-PAS has shown to be an excellent choice for pore structure characterization for glasses with multiple alteration layers. Monte Carlo modeling predicted positron trajectories through the layers, and helped explain DB-PAS data, which showed that the deeper alteration layer without Fe had a similar composition and pore structure to layers on glass altered in water only.« less

Redistribution of Sr and rare earth elements in the matrices of CV3 carbonaceous chondrites during aqueous alteration in their parent body

NASA Astrophysics Data System (ADS)

Jogo, Kaori; Ito, Motoo; Nakamura, Tomoki; Kobayashi, Sachio; Lee, Jong Ik

2018-03-01

We measured the abundances of Sr and rare earth elements (REEs) in the matrices of five CV3 carbonaceous chondrites: Meteorite Hills (MET) 00430, MET 01070, La Paz ice field (LAP) 02206, Asuka (A) 881317 and Roberts Massif (RBT) 04143. In the MET 00430 and MET 01074 matrices, the Sr/CI and light REE (LREE, La-Nd)/CI ratios positively correlate with the amounts of Ca-rich secondary minerals, which formed during aqueous alteration in the CV3 chondrite parent body. In contrast, in the LAP 02206 and RBT 04143 matrices, although the Sr/CI ratios correlate with the amounts of Ca-rich secondary minerals, the LREE/CI ratios vary independently from the amounts of any secondary minerals. This suggests that the LREE/CI ratios in these matrices were produced prior to the parent body alteration, probably in the solar nebula. The LREE/CI ratios of the LAP 02206 and RBT 04143 matrices reveal the mixing process of matrix minerals prior to the accretion of the CV3 chondrite parent body. The mixing degrees of matrix minerals might be different between these two matrices. Because solid materials would be mixed over time according to the radial diffusion model of a turbulent disk, the matrix minerals consisting of LAP 02206 and RBT 04143 matrices might be incorporated into their parent body with different timing.

Mineralogy and composition of matrix and chondrule rims in carbonaceous chondrites

NASA Technical Reports Server (NTRS)

Zolensky, Michael; Barrett, Ruth; Browning, Lauren

1993-01-01

The degree of compositional variation of fine-grained minerals displayed by the members within any carbonaceous chondrite group (i.e., CI, CM, CV, CR) is a direct reflection of the range of aqueous alteration assemblages present. Matrix and fine-grained chondrule rims within any particular carbonaceous chondrite are mineralogically nearly identical to one another, but not necessarily similar in bulk elemental composition, even though they have subsequently experienced postaccretional secondary processing (aqueous alteration) under identical conditions. We propose that CO chondrites experienced parent body conditions of low f(O2), low water/rock ratios, and temperatures below 50 C. CR chondrites experienced higher water/rock ratios, potentially higher temperatures (not above 150 C), and a wide range of f(O2). The alteration mineralogy of CV chondrites indicates water/rock ratios at the high end (at least) of the range for CR chondrites, Essebi, and MAC 87300. CM chondrites experienced temperatures below 50 C, low f(O2) and low water/rock ratios, except EET 83334, which probably experienced relatively higher f(O2), and B-7904 and Y-86720, which experienced postalteration temperatures in the range 500-700 C. Most CI chondrites experienced temperatures between 50 and 150 C, relatively high water/rock ratios, and variable f(O2). Y-82162 witnessed postalteration heating, possibly as high as 400 C.

Aqueous Alteration of Enstatite Chondrites

NASA Technical Reports Server (NTRS)

Zolensky, M. E.; Ziegler, K.; Weisberg, M. K.; Gounelle, M.; Berger, E. L.; Le, L.; Ivanov, A.

2014-01-01

The Kaidun meteorite is different from all other meteorites [1], consisting largely of a mixture of “incompatible” types of meteoritic material – carbonaceous and enstatite chondrites, i.e. corre-sponding to the most oxidized and the most reduced samples of meteorite materials, including CI1, CM1-2, CV3, EH3-5, and EL3. In addition to these, minor amounts of ordinary and R chondrites are present. In addition, approximately half of the Kaidun lithologies are new materials not known as separate meteorites. Among these are aqueously altered enstatite chondrites [1], which are of considerable interest because they testify that not all reduced asteroids escaped late-stage oxidation, and hydrolysis, and also because hydrated poorly crystalline Si-Fe phase, which in turn is re-placed by serpentine (Figs 3-5). In the end the only indication of the original presence of metal is the re-sidual carbides. In other enstatite chondrite lithogies (of uncertain type) original silicates and metal have been thoroughly replaced by an assemblage of authi-genic plagioclase laths, calcite boxwork, and occasion-al residual grains of silica, Cr-rich troilite, ilmenite, and rare sulfides including heideite (Fig. 6). Fe and S have been largely leached from the rock (Fig. 4). Again the accessory phases are the first clue to the original character of the rock, which can be verified by O isotopes. It is fortunate that Kaidun displays every step of the alteration process.

Anomalous Micellization of Pluronic Block Copolymers

NASA Astrophysics Data System (ADS)

Leonardi, Amanda; Ryu, Chang Y.

2014-03-01

Poly(ethylene oxide) - poly(propylene oxide) - poly(ethylene oxide) (PEO-PPO-PEO) block copolymers, commercially known as Pluronics, are a unique family of amphiphilic triblock polymers, which self-assemble into micelles in aqueous solution. These copolymers have shown promise in therapeutic, biomedical, cosmetic, and nanotech applications. As-received samples of Pluronics contain low molecular weight impurities (introduced during the manufacturing and processing), that are ignored in most applications. It has been observed, however, that in semi-dilute aqueous solutions, at concentrations above 1 wt%, the temperature dependent micellization behavior of the Pluronics is altered. Anomalous behavior includes a shift of the critical micellization temperature and formation of large aggregates at intermediate temperatures before stable sized micelles form. We attribute this behavior to the low molecular weight impurities that are inherent to the Pluronics which interfere with the micellization process. Through the use of Dynamic Light Scattering and HPLC, we compared the anomalous behavior of different Pluronics of different impurity levels to their purified counterparts.

Mössbauer spectroscopy on Mars: goethite in the Columbia Hills at Gusev crater

NASA Astrophysics Data System (ADS)

Klingelhöfer, G.; Degrave, E.; Morris, R. V.; van Alboom, A.; de Resende, V. G.; de Souza, P. A.; Rodionov, D.; Schröder, C.; Ming, D. W.; Yen, A.

2005-11-01

In January 2004 the USA space agency NASA landed two rovers on the surface of Mars, both carrying the Mainz Mössbauer spectrometer MIMOS II. The instrument on the Mars-Exploration-Rover (MER) Spirit analyzed soils and rocks on the plains and in the Columbia Hills of Gusev crater landing site on Mars. The surface material in the plains have an olivine basaltic signature [1, 5] suggesting physical rather than chemical weathering processes present in the plains. The Mössbauer signature for the Columbia Hills surface material is very different ranging from nearly unaltered material to highly altered material. Some of the rocks, in particular a rock named Clovis, contain a significant amount of the Fe oxyhydroxide goethite, α-FeOOH, which is mineralogical evidence for aqueous processes because it is formed only under aqueous conditions. In this paper we describe the analysis of these data using hyperfine field distributions (HFD) and discuss the results in comparison to terrestrial analogues.

Rim Structure, Stratigraphy, and Aqueous Alteration Exposures Along Opportunity Rover's Traverse of the Noachian Endeavour Crater

NASA Technical Reports Server (NTRS)

Crumpler, L.S.; Arvidson, R. E.; Golombek, M.; Grant, J. A.; Jolliff, B. L.; Mittlefehldt, D. W.

2017-01-01

The Mars Exploration Rover Opportunity has traversed 10.2 kilometers along segments of the west rim of the 22-kilometer-diameter Noachian Endeavour impact crater as of sol 4608 (01/09/17). The stratigraphy, attitude of units, lithology, and degradation state of bedrock outcrops exposed on the crater rim have been examined in situ and placed in geologic context. Structures within the rim and differences in physical properties of the identified lithologies have played important roles in localizing outcrops bearing evidence of aqueous alteration.

Transmission Electron Microscope Observations of Phyllosilicate Development During Experimental Aqueous Alteration of Allende

NASA Technical Reports Server (NTRS)

Jones, C. L.; Brearley, A. J.

2000-01-01

Samples of Allende have been altered hydrothermally under oxidizing conditions at 200 C. TEM studies show that within 30 days evidence of replacement of matrix olivines by fine-grained serpentine is present and by 90 days complete alteration of many grains has occurred.

Mineral-organic interfacial processes: potential roles in the origins of life.

PubMed

Cleaves, H James; Michalkova Scott, Andrea; Hill, Frances C; Leszczynski, Jerzy; Sahai, Nita; Hazen, Robert

2012-08-21

Life is believed to have originated on Earth ∼4.4-3.5 Ga ago, via processes in which organic compounds supplied by the environment self-organized, in some geochemical environmental niches, into systems capable of replication with hereditary mutation. This process is generally supposed to have occurred in an aqueous environment and, likely, in the presence of minerals. Mineral surfaces present rich opportunities for heterogeneous catalysis and concentration which may have significantly altered and directed the process of prebiotic organic complexification leading to life. We review here general concepts in prebiotic mineral-organic interfacial processes, as well as recent advances in the study of mineral surface-organic interactions of potential relevance to understanding the origin of life.

Monte Carlo simulations of coupled diffusion and surface reactions during the aqueous corrosion of borosilicate glasses

DOE PAGES

Kerisit, Sebastien; Pierce, Eric M.; Ryan, Joseph V.

2014-09-19

Borosilicate nuclear waste glasses develop complex altered layers as a result of coupled processes such as hydrolysis of network species, condensation of Si species, and diffusion. However, diffusion has often been overlooked in Monte Carlo models of the aqueous corrosion of borosilicate glasses. Therefore, in this paper three different models for dissolved Si diffusion in the altered layer were implemented in a Monte Carlo model and evaluated for glasses in the compositional range (75 - x) mol% SiO 2 (12.5 + x/2) mol% B 2O 3 and (12.5 + x/2) mol% Na 2O, where 0 ≤ x ≤ 20%, andmore » corroded in static conditions at a surface-area-to-volume ratio of 1000 m -1. The three models considered instantaneous homogenization (M1), linear concentration gradients (M2), and concentration profiles determined by solving Fick's 2nd law using a finite difference method (M3). Model M3 revealed that concentration profiles in the altered layer are not linear and show changes in shape and magnitude as corrosion progresses, unlike those assumed in model M2. Furthermore, model M3 showed that, for borosilicate glasses with a high forward dissolution rate compared to the diffusion rate, the gradual polymerization and densification of the altered layer is significantly delayed compared to models M1 and M2. Finally, models M1 and M2 were found to be appropriate models only for glasses with high release rates such as simple borosilicate glasses with low ZrO 2 content.« less

Chemical Compositional Indications of Aqueous Alteration for Whitewater Lake Boxworks, Veneers and Veins at Cape York, Mars

NASA Astrophysics Data System (ADS)

Clark, Benton; Gellert, R.; Squyres, S.; Arvidson, R.; Yen, A.; Rice, J.; Athena Science Team

2013-10-01

An area of partially-veneered, flat-lying rocks which also includes boxwork and linear veins contains a variety of compositions which are each indicative of minor to major aqueous alteration processes in the Cape York rim of Endeavour Crater. As analyzed by APXS x-ray fluorescence spectroscopy, the sets of unique elemental compositions correspond variously to Al-Si rich clays in boxwork veins, with Fe- and Cl-enriched salt veneers (Esperance samples); swarms of Ca sulfate veins (Ortiz samples); and, as indicated by remote sensing, mafic smectite alteration products in veneers (Chelmsford covering Azilda samples). Multiple offset analyses by APXS reveal clear trends and associations of certain elements, allowing inferences of mineralogies. In contrast to the acidic environment deduced for the genesis of the multiple-sulfate Burns formation sediments and shallow ferric-rich sulfate deposits beneath soils, these alteration products formed at more near-neutral pH, often with major chemical segregations and requiring high water-rock ratios comparable to a wide range of eminently habitable terrestrial environments. Several of these compositions are also rated high with respect to their potential for preservation of organic materials and biomarkers. Within distances of just tens of meters inside this so-called Whitewater Lake unit, this broad diversity exemplifies the tantalizing opportunities as well as challenges for future sample return missions to the red planet, which in this case could also be expanded to include nearby samples of Burns Fm sandstones, hematite concretions, light-toned spherules (Kirkwood), large gypsum veins (Homestake), martian global soils and surface dust.

The Secondary Structure of Human Hageman Factor (Factor XII) and its Alteration by Activating Agents

PubMed Central

McMillin, Carl R.; Saito, Hidehiko; Ratnoff, Oscar D.; Walton, Alan G.

1974-01-01

Hageman factor (factor XII) is activated by exposure to surfaces such as glass or by solutions of certain compounds, notably ellagic acid. Changes in the structure of Hageman factor accompanying activation have been examined in this study by circular dichroism spectroscopy. The spectrum of unactivated Hageman factor in aqueous solutions suggests that its conformation is mainly aperiodic. Various perturbants altered the conformation of Hageman factor in differing ways, demonstrating the sensitivity of Hageman factor to its environment. After activation of Hageman factor with solutions of ellagic acid, a negative trough appeared in the region of the circular dichroism spectrum commonly assigned to tyrosine residues, along with other minor changes in the peptide spectral region. Some of these changes are similar to changes that occurred upon partial neutralization of the basic residues at alkali pH. Activation of Hageman factor by adsorption to quartz surfaces (in an aqueous environment) also produced changes similar to those in the ellagic acid-activated Hageman factor, including the negative ellipticity in the tyrosine region. These observations suggest that the activation process may be related to a change in status of some of the basic amino acid residues, coupled with a specific change in the environment of some tyrosine residues. The importance of these changes during the activation process remains to be determined. The sensitivity of Hageman factor to its environment is consistent with the view that the initiation of clotting by exposure of plasma to appropriate agents is brought about by alterations in the conformation of Hageman factor that occur in the apparent absence of Fletcher factor or other recognized clotting factors. Images PMID:4373492

Tracking the weathering of basalts on Mars using lithium isotope fractionation models

PubMed Central

Losa‐Adams, Elisabeth; Gil‐Lozano, Carolina; Gago‐Duport, Luis; Uceda, Esther R.; Squyres, Steven W.; Rodríguez, J. Alexis P.; Davila, Alfonso F.; McKay, Christopher P.

2015-01-01

Abstract Lithium (Li), the lightest of the alkali elements, has geochemical properties that include high aqueous solubility (Li is the most fluid mobile element) and high relative abundance in basalt‐forming minerals (values ranking between 0.2 and 12 ppm). Li isotopes are particularly subject to fractionation because the two stable isotopes of lithium—7Li and 6Li—have a large relative mass difference (∼15%) that results in significant fractionation between water and solid phases. The extent of Li isotope fractionation during aqueous alteration of basalt depends on the dissolution rate of primary minerals—the source of Li—and on the precipitation kinetics, leading to formation of secondary phases. Consequently, a detailed analysis of Li isotopic ratios in both solution and secondary mineral lattices could provide clues about past Martian weathering conditions, including weathering extent, temperature, pH, supersaturation, and evaporation rate of the initial solutions in contact with basalt rocks. In this paper, we discuss ways in which Martian aqueous processes could have lead to Li isotope fractionation. We show that Li isotopic data obtained by future exploration of Mars could be relevant to highlighting different processes of Li isotopic fractionation in the past, and therefore to understanding basalt weathering and environmental conditions early in the planet's history. PMID:27642264

Understanding Surface Processes on Mars Through Study of Iron Oxides/Oxyhydroxides: Clues to Surface Alteration and Aqueous Processes

NASA Technical Reports Server (NTRS)

Bishop, J. L.; Mancinelli, R. L.; Dyar, M. D.; Parente, M.; Drief, A.; Lane, M. D.; Murad, E.

2006-01-01

We are performing oxidation and reduction reactions on hydrated ferric oxide minerals in order to investigate how these might alter under a variety of conditions on the surface of Mars. Preliminary experiments on ferrihydrite and goethite showed that heating these minerals in a dry oxidizing environment produces fine-grained hematite, while heating these minerals in a reducing environment produces fine-grained magnetite. Under Mars-like oxidation levels this magnetite then oxidizes to maghemite. These reactions are dependent on the presence of water and organic material that can act as a reductant. We are using reflectance and Mossbauer spectroscopy to characterize the reaction products and TEM to analyze the sample texture. Our preliminary results indicate that magnetite and maghemite could be formed in the soil on Mars from ferrihydrite and goethite if organics were present on early Mars.

Aqueous Alteration of Endeavour Crater Rim Apron Rocks

NASA Technical Reports Server (NTRS)

Mittlefehldt, David W.; Ming, Douglas W.; Gellert, Ralf; Clark, Benton C.; Morris, Richard V.; Yen, Albert S.; Arvidson, Raymond E.; Crumpler, Larry S.; Farrand, William H.; Grant, John A.;

Aqueous Alteration of Endeavour Crater Rim Apron Rocks

NASA Astrophysics Data System (ADS)

Ming, D. W.; Mittlefehldt, D. W.; Gellert, R.; Clark, B. C.; Morris, R. V.; Yen, A. S.; Arvidson, R. E.; Crumpler, L. S.; Farrand, W. H.; Grant, J. A., III; Jolliff, B. L.; Parker, T. J.; Peretyazhko, T.

2014-12-01

Mars Exploration Rover Opportunity is exploring Noachian age rocks of the rim of 22 km diameter Endeavour crater. Overlying the pre-impact lithologies and rim breccias is a thin apron of fine-grained sediments, the Grasberg fm, forming annuli on the lower slopes of rim segments. Hesperian Burns fm sandstones overly the Grasberg fm. Grasberg rocks have major element compositions that are distinct from Burns fm sandstones, especially when comparing interior compositions exposed by the Rock Abrasion Tool. Grasberg rocks are also different from Endeavour rim breccias, but have general compositional similarities to them. Grasberg sediments are plausibly fine-grained materials derived from the impact breccias. Veins of CaSO4 transect Grasberg fm rocks demonstrating post-formation aqueous alteration. Minor/trace elements show variations consistent with mobilization by aqueous fluids. Grasberg fm rocks have low Mn and high Fe/Mn ratios compared to the other lithologies. Manganese likely was mobilized and removed from the Grasberg host rock by redox reactions. We posit that Fe2+ from acidic solutions associated with formation of the Burns sulfate-rich sandstones acted as an electron donor to reduce more oxidized Mn to Mn2+. The Fe contents of Grasberg rocks are slightly higher than in other rocks suggesting precipitation of Fe phases in Grasberg materials. Pancam spectra show that Grasberg rocks have a higher fraction of ferric oxide minerals than other Endeavour rim rocks. Solutions transported Mn2+ into the Endeavour rim materials and oxidized and/or precipitated it in them. Grasberg has higher contents of the mobile elements K, Zn, Cl, and Br compared to the rim materials. Similar enrichments of mobile elements were measured by the Spirit APXS on West Spur and around Home Plate in Gusev crater. Enhancements in these elements are attributed to interactions of hydrothermal acidic fluids with the host rocks. Interactions of fluids with the Grasberg fm postdate the genesis of the Endeavour rim phyllosilicates. The aqueous alteration history of Endeavour rim rocks is complicated by different styles of alteration that have spanned the Noachian and Hesperian. Late stage acidic aqueous alteration of Grasberg fm materials is likely penecontemporaneous with the diagenesis of the sulfate-rich sediments of Meridiani Planum.

Preliminary Mineralogic and Stable Isotope Studies of Altered Summit and Flank Rocks and Osceola Mudflow Deposits on Mount Rainier, Washington

USGS Publications Warehouse

Rye, Robert O.; Breit, George N.; Zimbelman, David R.

2003-01-01

About 5600 years ago part of Mount Rainier?s edifice collapsed with the resultant Osceola Mudflow traveling more than 120 km and covering an area of at least 505 km2. Mineralogic and stable isotope studies were conducted on altered rocks from outcrops near the summit and east flank of the volcano and samples of clasts and matrix from the Osceola Mudflow. Results of these analyses are used to constrain processes responsible for pre-collapse alteration and provide insight into the role of alteration in edifice instability prior to the Osceola collapse event. Jarosite, pyrite, alunite, and kaolinite occur in hydrothermally altered rock exposed in summit scarps formed by edifice collapse events and in altered rock within the east-west structural zone (EWSZ) of the volcano?s east flank. Deposits of the Osceola Mudflow contain clasts of variably altered and unaltered andesite within a clay-rich matrix. Minerals detected in samples from the edifice are also present in many of the clasts. The matrix includes abundant smectite, kaolinite and variably abundant jarosite. Hydrothermal fluid compositions calculated from hydrogen and oxygen isotope data of alunite, and smectite on Mount Rainier reflect mixing of magmatic and meteoric waters. The range in the dD values of modern meteoric water on the volcano (-85 to 155?) reflect the influence of elevation on the dD of precipitation. The d34S and d18OSO4 values of alunite, gypsum and jarosite are distinct but together range from 1.7 to 17.6? and -12.3 to 15.0?, respectively; both parameters increase from jarosite to gypsum to alunite. The variations in sulfur isotope composition are attributed to the varying contributions of disproportionation of magmatic SO2, the supergene oxidation of hydrothermal pyrite and possible oxidation of H2S to the parent aqueous sulfate. The 18OSO4 values of jarosite are the lowest recorded for the mineral, consistent with a supergene origin. The mineralogy and isotope composition of alteration minerals define two and possibly three environments of alteration. At deeper levels magmatic vapor, H2S, SO2 and other gases from venting magmas migrated upward and condensed into the meteoric water. Disproportionation of SO2 into aqueous sulfate and H2S resulted in acid-sulfate (alunite + kaolinite + pyrite) and related argillic and propylitic alteration envelopes in a magmatic hydrothermal environment. At shallow levels H2S reacted with andesite to form pyrite that is associated with smectite along fractures on both the flanks and upper edifice. It is not clear to what extent H2S was oxidized by atmospheric O2 to form aqueous sulfate in a steam-heated environment. Near the ground surface, pyrite is oxidized by atmospheric oxygen resulting in soluble iron-and aluminum-hydroxysulfates. These supergene hydroxysulfates, which may also form around fumaroles from the oxidation of H2S, are subject to continuous solution and redeposition.

What Are Space Exposure Histories Telling Us about CM Carbonaceous Chondrites?

NASA Technical Reports Server (NTRS)

Takenouchi, A.; Zolensky, Michael E.; Nishiizumi, K.; Caffee, M.; Velbel, M. A.; Ross, K.; Zolensky, P.; Le, L.; Imae, N.; Yamaguchi, A.;

On the electron affinity of cytosine in bulk water and at hydrophobic aqueous interfaces.

PubMed

Vöhringer-Martinez, Esteban; Dörner, Ciro; Abel, Bernd

2014-10-01

In the past one possible mechanism of DNA damage in bulk water has been attributed to the presence of hydrated electrons in water. Recently, one important property of hydrated electrons, namely their binding energy, was reported to be smaller at hydrophobic interfaces than in bulk aqueous solution. This possibly opens up new reaction possibilities with different solutes such as the DNA at hydrophobic, aqueous interfaces. Here, we use QM/MM molecular dynamics simulation to study how the molecular environment at the vacuum-water interface and in the bulk alters the electron affinity of cytosine being a characteristic part of the DNA. The electron affinity at the interface is closer to the corresponding binding energy of the partially hydrated electron. The increased energy resonance makes the electron capture process more probable and suggests that hydrated electrons at hydrophobic interfaces may be more reactive than the fully hydrated ones. Additionally, we found that the relaxation of the anionic form after electron attachment also induces a proton transfer from the surrounding solvent that was confirmed by comparison with the experimental reduction potential.

Acid Sulfate Alteration on Mars

NASA Technical Reports Server (NTRS)

Ming, D. W.; Morris, R. V.

2016-01-01

A variety of mineralogical and geochemical indicators for aqueous alteration on Mars have been identified by a combination of surface and orbital robotic missions, telescopic observations, characterization of Martian meteorites, and laboratory and terrestrial analog studies. Acid sulfate alteration has been identified at all three landing sites visited by NASA rover missions (Spirit, Opportunity, and Curiosity). Spirit landed in Gusev crater in 2004 and discovered Fe-sulfates and materials that have been extensively leached by acid sulfate solutions. Opportunity landing on the plains of Meridiani Planum also in 2004 where the rover encountered large abundances of jarosite and hematite in sedimentary rocks. Curiosity landed in Gale crater in 2012 and has characterized fluvial, deltaic, and lacustrine sediments. Jarosite and hematite were discovered in some of the lacustrine sediments. The high elemental abundance of sulfur in surface materials is obvious evidence that sulfate has played a major role in aqueous processes at all landing sites on Mars. The sulfate-rich outcrop at Meridiani Planum has an SO3 content of up to 25 wt.%. The interiors of rocks and outcrops on the Columbia Hills within Gusev crater have up to 8 wt.% SO3. Soils at both sites generally have between 5 to 14 wt.% SO3, and several soils in Gusev crater contain around 30 wt.% SO3. After normalization of major element compositions to a SO3-free basis, the bulk compositions of these materials are basaltic, with a few exceptions in Gusev crater and in lacustrine mudstones in Gale crater. These observations suggest that materials encountered by the rovers were derived from basaltic precursors by acid sulfate alteration under nearly isochemical conditions (i.e., minimal leaching). There are several cases, however, where acid sulfate alteration minerals (jarosite and hematite) formed in open hydrologic systems, e.g., in Gale crater lacustrine mudstones. Several hypotheses have been suggested for the aqueous formation of sulfate-bearing phases under acidic conditions on the surface of Mars including (1) sulfuric acid weathering of basaltic materials; (2) oxidative weathering of ultramafic igneous rocks containing sulfides; (3) acid fog weathering of basaltic materials, and (4) near-neutral pH subsurface solutions rich in Fe2(+) that were rapidly oxidized to Fe3(+), which produced excess acidity as iron was oxidized on exposure to O2 or photo-oxidized by ultraviolet radiation at the martian surface. Next, we briefly describe evidence for these hypothesis.

Aqueous processes at Gusev crater inferred from physical properties of rocks and soils along the Spirit traverse

USGS Publications Warehouse

Cabrol, N.A.; Farmer, J.D.; Grin, E.A.; Ritcher, L.; Soderblom, L.; Li, R.; Herkenhoff, K.; Landis, G.A.; Arvidson, R. E.

2006-01-01

Gusev crater was selected as the landing site for Spirit on the basis of morphological evidence of long-lasting water activity, including possibly fluvial and lacustrine episodes. From the Columbia Memorial Station to the Columbia Hills, Spirit's traverse provides a journey back in time, from relatively recent volcanic plains showing little evidence for aqueous processes up to the older hills, where rock and soil composition are drastically different. For the first 156 sols, the only evidence of water action was weathering rinds, vein fillings, and soil crust cementation by salts. The trenches of Sols 112-145 marked the first significant findings of increased concentrations of sulfur and magnesium varying in parallel, suggesting that they be paired as magnesium-sulfate. Spirit's arrival at West Spur coincided with a shift in rock and soil composition with observations hinting at substantial amounts of water in Gusev's past. We used the Microscopic Imager data up to Sol 431 to analyze rock and soil properties and infer plausible types and magnitude of aqueous processes through time. We show the role played early by topography and structure. The morphology, texture, and deep alteration shown by the rocks in West Spur and the Columbia Hills Formation (CHF) suggest conditions that are not met in present-day Mars and required a wetter environment, which could have included transport of sulfur, chlorine, and bromine in water, vapor in volcanic gases, hydrothermal circulation, or saturation in a briny fluid containing the same elements. Changing conditions that might have affected flow circulation are suggested by different textural and morphological characteristics between the rocks in the CHF and those of the plains, with higher porosity proxy, higher void ratio, and higher water storage potential in the CHF. Soils were used to assess aqueous processes and water pathways in the top layers of modern soils. We conclude that infiltration might have become more difficult with time. Copyright 2006 by the American Geophysical Union.

Proceedings of the 40th Lunar and Planetary Science Conference

NASA Technical Reports Server (NTRS)

2009-01-01

The 40th Lunar and Planetary Science Conference included sessions on: Phoenix: Exploration of the Martian Arctic; Origin and Early Evolution of the Moon; Comet Wild 2: Mineralogy and More; Astrobiology: Meteorites, Microbes, Hydrous Habitats, and Irradiated Ices; Phoenix: Soil, Chemistry, and Habitability; Planetary Differentiation; Presolar Grains: Structures and Origins; SPECIAL SESSION: Venus Atmosphere: Venus Express and Future Missions; Mars Polar Caps: Past and Present; SPECIAL SESSION: Lunar Missions: Results from Kaguya, Chang'e-1, and Chandrayaan-1, Part I; 5 Early Nebula Processes and Models; SPECIAL SESSION: Icy Satellites of Jupiter and Saturn: Cosmic Gymnasts; Mars: Ground Ice and Climate Change; SPECIAL SESSION: Lunar Missions: Results from Kaguya, Chang'e-1, and Chandrayaan-1, Part II; Chondrite Parent-Body Processes; SPECIAL SESSION: Icy Satellites of Jupiter and Saturn: Salubrious Surfaces; SNC Meteorites; Ancient Martian Crust: Primary Mineralogy and Aqueous Alteration; SPECIAL SESSION: Messenger at Mercury: A Global Perspective on the Innermost Planet; CAIs and Chondrules: Records of Early Solar System Processes; Small Bodies: Shapes of Things to Come; Sulfur on Mars: Rocks, Soils, and Cycling Processes; Mercury: Evolution and Tectonics; Venus Geology, Volcanism, Tectonics, and Resurfacing; Asteroid-Meteorite Connections; Impacts I: Models and Experiments; Solar Wind and Genesis: Measurements and Interpretation; Mars: Aqueous Processes; Magmatic Volatiles and Eruptive Conditions of Lunar Basalts; Comparative Planetology; Interstellar Matter: Origins and Relationships; Impacts II: Craters and Ejecta Mars: Tectonics and Dynamics; Mars Analogs I: Geological; Exploring the Diversity of Lunar Lithologies with Sample Analyses and Remote Sensing; Chondrite Accretion and Early History; Science Instruments for the Mars Science Lander; . Martian Gullies: Morphology and Origins; Mars: Dunes, Dust, and Wind; Mars: Volcanism; Early Solar System Chronology; Seek Out and Explore: Upcoming and Future Missions; Mars: Early History and Impact Processes; Mars Analogs II: Chemical and Spectral; Achondrites and their Parent Bodies; and Planning for Future Exploration of the Moon The poster sessions were: Lunar Missions: Results from Kaguya, Chang'e-1, and Chandrayaan-1; LRO and LCROSS; Geophysical Analysis of the Lunar Surface and Interior; Remote Observation and Geologic Mapping of the Lunar Surface; Lunar Spectroscopy; Venus Geology, Geophysics, Mapping, and Sampling; Planetary Differentiation; Bunburra and Buzzard Coulee: Recent Meteorite Falls; Meteorites: Terrestrial History; CAIs and Chondrules: Records of Early Solar System Processes; Volatile and Organic Compounds in Chondrites; Crashing Chondrites: Impact, Shock, and Melting; Ureilite Studies; Petrology and Mineralogy of the SNC Meteorites; Martian Meteorites; Phoenix Landing Site: Perchlorate and Other Tasty Treats; Mars Polar Atmospheres and Climate Modeling; Mars Polar Investigations; Mars Near-Surface Ice; Mars: A Volatile-Rich Planet; Mars: Geochemistry and Alteration Processes; Martian Phyllosilicates: Identification, Formation, and Alteration; Astrobiology; Instrument Concepts, Systems, and Probes for Investigating Rocks and Regolith; Seeing is Believing: UV, VIS, IR, X- and Gamma-Ray Camera and Spectrometer Instruments; Up Close and Personal: In Situ Analysis with Laser-Induced Breakdown Spectroscopy and Mass Spectrometry; Jupiter and Inscrutable Io; Tantalizing Titan; Enigmatic Enceladus and Intriguing Iapetus; Icy Satellites: Cryptic Craters; Icy Satellites: Gelid Geology/Geophysics; Icy Satellites: Cool Chemistry and Spectacular Spectroscopy; Asteroids and Comets; Comet Wild 2: Mineralogy and More; Hypervelocity Impacts: Stardust Models, LDEF, and ISPE; Presolar Grains; Early Nebular Processes: Models and Isotopes; Solar Wind and Genesis: Measurements and Interpretation; Education and Public Outreach; Mercury; Pursuing Lunar Exploration; Sources and Eruptionf Lunar Basalts; Chemical and Physical Properties of the Lunar Regolith; Lunar Dust and Transient Surface Phenomena; Lunar Databases and Data Restoration; Meteoritic Samples of the Moon; Chondrites, Their Clasts, and Alteration; Achondrites: Primitive and Not So Primitive; Iron Meteorites; Meteorite Methodology; Antarctic Micrometeorites; HEDs and Vesta; Dust Formation and Transformation; Interstellar Organic Matter; Early Solar System Chronology; Comparative Planetology; Impacts I: Models and Experiments; Impacts II: Craters and Ejecta; Mars: Volcanism; Mars: Tectonics and Dynamics; Martian Stratigraphy: Understanding the Geologic History of Mars Through the Sedimentary Rock Record; Mars: Valleys and Valley Networks; Mars: Aqueous Processes in Valles Marineris and the Southern Highlands; Mars: Aqueous Geomorphology; Martian Gullies: Morphology and Origins; Mars: Dunes, Dust, and Wind; Mars: Remote Sensing; Mars: Geologic Mapping, Photogrammetry, and Cratering; Martian Mineralogy: Constraints from Missions and Laboratory Investigations; Mars Analogs: Chemical and Physical; Mars Analogs: Sulfates and Sulfides; Missions: Approaches, Architectures, Analogs, and Actualities; Not Just Skin Deep: Electron Microscopy, Heat Flow, Radar, and Seismology Instruments and Planetary Data Systems, Techniques, and Interpretation.

Low-Temperature, Aqueous Alteration of Soil in Wright Valley, Antarctica, Compared with Aqueous Alteration on Mars

NASA Technical Reports Server (NTRS)

Wentworth, S. J.; Gibson, E. K., Jr.; McKay, D. S.

2003-01-01

The Dry Valleys of Antarctica are possibly one of the best analogs on Earth of the environment at the surface of Mars. Many types of research have been focused on the Dry Valleys, partly because of the potential application to Mars, and also because of the importance of the Dry Valleys in understanding the characteristics and development of terrestrial polar deserts. In 1983, we published a detailed study of weathering products and soil chemistry in a soil pit at Prospect Mesa, Wright Valley, as a possible analog to Mars. Much more is now known about Mars, so we are re-examining that earlier work and comparing it with newer martian data. The Mars information most pertinent to this work includes (A) the strong evidence for recent aqueous activity on Mars, along with more recent evidence for present-day, near-surface water ice on Mars; and (B) the identification of meteorites from Mars and the subsequent, definitive proof that low temperature, aqueous weathering has occurred in these meteorites prior to their ejection from Mars.

Unmelted cosmic metal particles in the Indian Ocean

NASA Astrophysics Data System (ADS)

Shyam Prasad, Mokkapati; Rudraswami, N. G.; De Araujo, Agnelo A.; Khedekar, Vijay D.

2017-06-01

Fe-Ni metal is a common constituent of most meteorites and is an indicator of the thermal history of the respective meteorites, it is a diagnostic tool to distinguish between groups/subgroups of meteorites. In spite of over a million micrometeorites collected from various domains, reports of pure metallic particles among micrometeorites have been extremely rare. We report here the finding of a variety of cosmic metal particles such as kamacite, plessite, taenite, and Fe-Ni beads from deep-sea sediments of the Indian Ocean, a majority of which have entered the Earth unaffected by frictional heating during atmospheric entry. Such particles are known as components of meteorites but have never been found as individual entities. Their compositions suggest precursors from a variety of meteorite groups, thus providing an insight into the metal fluxes on the Earth. Some particles have undergone heating and oxidation to different levels during entry developing features similar to I-type cosmic spherules, suggesting atmospheric processing of individual kamacites/taenite grains as another hitherto unknown source for the I-type spherules. The particles have undergone postdepositional aqueous alteration transforming finally into the serpentine mineral cronstedtite. Aqueous alteration products of kamacite reflect the local microenvironment, therefore they have the potential to provide information on the composition of water in the solar nebula, on the parent bodies or on surfaces of planetary bodies. Our observations suggest it would take sustained burial in water for tens of thousands of years under cold conditions for kamacites to alter to cronstedtite.

A Study of Olivine Alteration to Iddingsite Using Raman Spectroscopy

NASA Technical Reports Server (NTRS)

Kuebler, K. E.; Wang, Alian; Haskin, L. A.; Jolliff, B. L.

2003-01-01

A crucial task of Mars surface science is to determine past environmental conditions, especially aqueous environments and their nature. Identification of mineral alteration by water is one way to do this. Recent work interprets TES spectra as indicating altered basalt on Mars. Olivine, a primary basaltic mineral, is easily altered by aqueous solutions. Alteration assemblages of olivine may be specific to deuteric, hydrothermal, surface water, or metamorphic environments. Raman spectra are produced by molecular vibrations and provide direct means for studying and identifying alteration products. Here, we present a combined study of changes in the chemical composition and Raman spectra of an olivine as it alters to iddingsite. Iddingsite is found in some SNC meteorites and is presumably present on Mars. The term 'iddingsite' has been used as a catch-all term to describe reddish alteration products of olivine, although some authors ascribe a narrower definition: an angstrom-scale intergrowth of goethite and smectite (presumably saponite) formed in an oxidizing and fluid-rich environment. Alteration conserves Fe (albeit oxidized) but requires addition of Al and H2O and removal of Mg and Si. The smectite that forms may be removed by continued alteration. Dehydration of the goethite forms hematite. Our purpose is to study the mineral assemblage, determine the structural and chemical variability of the components with respect to the degree of alteration, and to find spectral indicators of alteration that will be useful during in-situ analyses on Mars.

Germanium Enrichments in Sedimentary Rocks in Gale Crater, Mars: Constraining the Timing of Alteration and Character of the Protolith

NASA Technical Reports Server (NTRS)

Berger, J. A.; Schmidt, M. E.; Gellert, R.; Campbell, J. L.; Boyd, N. I.; Elliott, B. E.; Fisk, M. R.; King, P. L.; Ming, D. W.; Perrett, G. M.;

Fluids during diagenesis and sulfate vein formation in sediments at Gale crater, Mars

NASA Astrophysics Data System (ADS)

Schwenzer, S. P.; Bridges, J. C.; Wiens, R. C.; Conrad, P. G.; Kelley, S. P.; Leveille, R.; Mangold, N.; Martín-Torres, J.; McAdam, A.; Newsom, H.; Zorzano, M. P.; Rapin, W.; Spray, J.; Treiman, A. H.; Westall, F.; Fairén, A. G.; Meslin, P.-Y.

2016-11-01

We model the fluids involved in the alteration processes recorded in the Sheepbed Member mudstones of Yellowknife Bay (YKB), Gale crater, Mars, as revealed by the Mars Science Laboratory Curiosity rover investigations. We compare the Gale crater waters with fluids modeled for shergottites, nakhlites, and the ancient meteorite ALH 84001, as well as rocks analyzed by the Mars Exploration rovers, and with terrestrial ground and surface waters. The aqueous solution present during sediment alteration associated with phyllosilicate formation at Gale was high in Na, K, and Si; had low Mg, Fe, and Al concentrations—relative to terrestrial groundwaters such as the Deccan Traps and other modeled Mars fluids; and had near neutral to alkaline pH. Ca and S species were present in the 10-3 to 10-2 concentration range. A fluid local to Gale crater strata produced the alteration products observed by Curiosity and subsequent evaporation of this groundwater-type fluid formed impure sulfate- and silica-rich deposits—veins or horizons. In a second, separate stage of alteration, partial dissolution of this sulfate-rich layer in Yellowknife Bay, or beyond, led to the pure sulfate veins observed in YKB. This scenario is analogous to similar processes identified at a terrestrial site in Triassic sediments with gypsum veins of the Mercia Mudstone Group in Watchet Bay, UK.

Spectral evidence for amorphous silicates in least-processed CO meteorites and their parent bodies

NASA Astrophysics Data System (ADS)

McAdam, Margaret M.; Sunshine, Jessica M.; Howard, Kieren T.; Alexander, Conel M.; McCoy, Timothy J.; Bus, Schelte J.

2018-05-01

Least-processed carbonaceous chondrites (carbonaceous chondrites that have experienced minimal aqueous alteration and thermal metamorphism) are characterized by their predominately amorphous iron-rich silicate interchondrule matrices and chondrule rims. This material is highly susceptible to destruction by the parent body processes of thermal metamorphism or aqueous alteration. The presence of abundant amorphous material in a meteorite indicates that the parent body, or at least a region of the parent body, experienced minimal processing since the time of accretion. The CO chemical group of carbonaceous chondrites has a significant number of these least-processed samples. We present visible/near-infrared and mid-infrared spectra of eight least-processed CO meteorites (petrologic type 3.0-3.1). In the visible/near-infrared, these COs are characterized by a broad weak feature that was first observed by Cloutis et al. (2012) to be at 1.3-μm and attributed to iron-rich amorphous silicate matrix materials. This feature is observed to be centered at 1.4-μm for terrestrially unweathered, least-processed CO meteorites. At mid-infrared wavelengths, a 21-μm feature, consistent with Si-O vibrations of amorphous materials and glasses, is also present. The spectral features of iron-rich amorphous silicate matrix are absent in both the near- and mid-infrared spectra of higher metamorphic grade COs because this material has recrystallized as crystalline olivine. Furthermore, spectra of least-processed primitive meteorites from other chemical groups (CRs, MET 00426 and QUE 99177, and C2-ungrouped Acfer 094), also exhibit a 21-μm feature. Thus, we conclude that the 1.4- and 21-μm features are characteristic of primitive least-processed meteorites from all chemical groups of carbonaceous chondrites. Finally, we present an IRTF + SPeX observation of asteroid (93) Minerva that has spectral similarities in the visible/near-infrared to the least-processed CO carbonaceous chondrites. While Minerva is not the only CO-like asteroid (e.g., Burbine et al., 2001), Minerva is likely the least-processed CO-like asteroid observed to date.

The Search for Surviving Direct Samples of Early Solar System Water

NASA Technical Reports Server (NTRS)

Zolensky, Michael

2016-01-01

We have become increasingly aware of the fundamental importance of water, and aqueous alteration, on primitive solar-system bodies. All classes of astromaterials studied show some degree of interaction with aqueous fluids. Nevertheless, we are still lacking fundamental information such as the location and timing of the aqueous alteration and the detailed nature of the aqueous fluids. Halite crystals in two meteorite regolith breccias were found to contain aqueous fluid inclusions (brines) trapped approx. 4.5 BYBP. Heating/freezing studies of the aqueous fluid inclusions in these halites demonstrated that they were trapped near 25 C. The initial results of our O and H isotopic measurements on these brine inclusions can be explained by a simple model mixing asteroidal and cometary water. We have been analyzing solids and organics trapped alongside the brines in the halites by FTIR, C-XANES, SXRD and Raman, as clues to the origin of the water. The organics show thermal effects that span the entire range witnessed by organics in all chondrite types. Since we identified water-soluble aromatics, including partially halogenated methanol, in some of the halite, we suspected amino acids were also present, but have thus far found that levels of amino acids were undetectable (which is very interesting). We have also been locating aqueous fluid inclusions in other astromaterials, principally carbonates in CI and CM chondrites. Although we have advanced slowly towards detailed analysis of these ancient brines, since they require techniques right at or just beyond current analytical capabilities, their eventual full characterization will completely open the window onto the origin and activity of early solar system water.

Origin of secondary sulfate minerals on active andesitic stratovolcanoes

USGS Publications Warehouse

Zimbelman, D.R.; Rye, R.O.; Breit, G.N.

2005-01-01

Sulfate minerals in altered rocks on the upper flanks and summits of active andesitic stratovolcanoes result from multiple processes. The origin of these sulfates at five active volcanoes, Citlalte??petl (Mexico), and Mount Adams, Hood, Rainier, and Shasta (Cascade Range, USA), was investigated using field observations, petrography, mineralogy, chemical modeling, and stable-isotope data. The four general groups of sulfate minerals identified are: (1) alunite group, (2) jarosite group, (3) readily soluble Fe- and Al-hydroxysulfates, and (4) simple alkaline-earth sulfates such as anhydrite, gypsum, and barite. Generalized assemblages of spatially associated secondary minerals were recognized: (1) alunite+silica??pyrite??kaolinite?? gypsum??sulfur, (2) jarosite+alunite+silica; (3) jarosite+smectite+silica??pyrite, (4) Fe- and Al-hydroxysulfates+silica, and (5) simple sulfates+silica??Al-hydroxysulfates??alunite. Isotopic data verify that all sulfate and sulfide minerals and their associated alteration assemblages result largely from the introduction of sulfur-bearing magmatic gases into meteoric water in the upper levels of the volcanoes. The sulfur and oxygen isotopic data for all minerals indicate the general mixing of aqueous sulfate derived from deep (largely disproportionation of SO2 in magmatic vapor) and shallow (oxidation of pyrite or H2S) sources. The hydrogen and oxygen isotopic data of alunite indicate the mixing of magmatic and meteoric fluids. Some alunite-group minerals, along with kaolinite, formed from sulfuric acid created by the disproportionation of SO2 in a condensing magmatic vapor. Such alunite, observed only in those volcanoes whose interiors are exposed by erosion or edifice collapse, may have ??34S values that reflect equilibrium (350??50 ??C) between aqueous sulfate and H2S. Alunite with ??34S values indicating disequilibrium between parent aqueous sulfate and H2S may form from aqueous sulfate created in higher level low-temperature environments in which SO2 is scrubbed out by groundwater or where H2S is oxidized. Jarosite-group minerals associated with smectite in only slightly altered volcanic rock are formed largely from aqueous sulfate derived from supergene oxidation of hydrothermal pyrite above the water table. Soluble Al- and Fehydroxysulfates form in low-pH surface environments, especially around fumaroles, and from the oxidation of hydrothermal pyrite. Anhydrite/gypsum, often associated with native sulfur and occasionally with small amounts of barite, also commonly form around fumaroles. Some occurrences of anhydrite/gypsum may be secondary, derived from the dissolution and reprecipitation of soluble sulfate. Edifice collapse may also reveal deep veins of anhydrite/gypsum??barite that formed from the mixing of saline fluids with magmatic sulfate and dilute meteoric water. Alteration along structures associated with both hydrothermal and supergene sulfates, as well as the position of paleo-water tables, may be important factors in edifice collapse and resulting debris flows at some volcanoes. ?? 2004 Elsevier B.V. All rights reserved.

Structural response of phyllomanganates to wet aging and aqueous Mn(II)

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

Hinkle, Margaret A. G.; Flynn, Elaine D.; Catalano, Jeffrey G.

Naturally occurring Mn(IV/III) oxides are often formed through microbial Mn(II) oxidation, resulting in reactive phyllomanganates with varying Mn(IV), Mn(III), and vacancy contents. Residual aqueous Mn(II) may adsorb in the interlayer of phyllomanganates above vacancies in their octahedral sheets. The potential for interlayer Mn(II)-layer Mn(IV) comproportionation reactions and subsequent formation of structural Mn(III) suggests that aqueous Mn(II) may cause phyllomanganate structural changes that alters mineral reactivity or trace metal scavenging. Here we examine the effects of aging phyllomanganates with varying initial vacancy and Mn(III) content in the presence and absence of dissolved Mn(II) at pH 4 and 7. Three phyllomanganates weremore » studied: two exhibiting turbostratic layer stacking (δ-MnO2 with high vacancy content and hexagonal birnessite with both vacancies and Mn(III) substitutions) and one with rotationally ordered layer stacking (triclinic birnessite containing predominantly Mn(III) substitutions). Structural analyses suggest that during aging at pH 4, Mn(II) adsorbs above vacancies and promotes the formation of phyllomanganates with rotationally ordered sheets and mixed symmetries arranged into supercells, while structural Mn(III) undergoes disproportionation. These structural changes at pH 4 correlate with reduced Mn(II) uptake onto triclinic and hexagonal birnessite after 25 days relative to 48 h of reaction, indicating that phyllomanganate reactivity decreases upon aging with Mn(II), or that recrystallization processes involving Mn(II) uptake occur over 25 days. At pH 7, Mn(II) adsorbs and causes limited structural effects, primarily increasing sheet stacking in δ-MnO2. These results show that aging-induced structural changes in phyllomanganates are affected by aqueous Mn(II), pH, and initial solid-phase Mn(III) content. In conclusion, such restructuring likely alters manganese oxide reactions with other constituents in environmental and geologic systems, particularly trace metals and redox-active compounds.« less

Structural response of phyllomanganates to wet aging and aqueous Mn(II)

DOE PAGES

Hinkle, Margaret A. G.; Flynn, Elaine D.; Catalano, Jeffrey G.

2016-08-06

Naturally occurring Mn(IV/III) oxides are often formed through microbial Mn(II) oxidation, resulting in reactive phyllomanganates with varying Mn(IV), Mn(III), and vacancy contents. Residual aqueous Mn(II) may adsorb in the interlayer of phyllomanganates above vacancies in their octahedral sheets. The potential for interlayer Mn(II)-layer Mn(IV) comproportionation reactions and subsequent formation of structural Mn(III) suggests that aqueous Mn(II) may cause phyllomanganate structural changes that alters mineral reactivity or trace metal scavenging. Here we examine the effects of aging phyllomanganates with varying initial vacancy and Mn(III) content in the presence and absence of dissolved Mn(II) at pH 4 and 7. Three phyllomanganates weremore » studied: two exhibiting turbostratic layer stacking (δ-MnO2 with high vacancy content and hexagonal birnessite with both vacancies and Mn(III) substitutions) and one with rotationally ordered layer stacking (triclinic birnessite containing predominantly Mn(III) substitutions). Structural analyses suggest that during aging at pH 4, Mn(II) adsorbs above vacancies and promotes the formation of phyllomanganates with rotationally ordered sheets and mixed symmetries arranged into supercells, while structural Mn(III) undergoes disproportionation. These structural changes at pH 4 correlate with reduced Mn(II) uptake onto triclinic and hexagonal birnessite after 25 days relative to 48 h of reaction, indicating that phyllomanganate reactivity decreases upon aging with Mn(II), or that recrystallization processes involving Mn(II) uptake occur over 25 days. At pH 7, Mn(II) adsorbs and causes limited structural effects, primarily increasing sheet stacking in δ-MnO2. These results show that aging-induced structural changes in phyllomanganates are affected by aqueous Mn(II), pH, and initial solid-phase Mn(III) content. In conclusion, such restructuring likely alters manganese oxide reactions with other constituents in environmental and geologic systems, particularly trace metals and redox-active compounds.« less

Ferric iron in primitive asteroids - A 0.43-micron absorption feature

NASA Technical Reports Server (NTRS)

Vilas, Faith; Hatch, Erin C.; Larson, Stephen M.; Sawyer, Scott R.; Gaffey, Michael J.

1993-01-01

A search of reflectance spectra of C- P-, D- and S-class asteroids to hunt for the Soret band near 0.4 micron that is indicative of porphyrins yielded an identification of an 0.43 micron absorption feature in 11 primitive asteroids of the C, P, and G classes and in one S-class asteroid. It is proposed that the feature is an Fe(3+) spin-forbidden transition in aqueously altered material, possibly located near 0.43 micron due to an enhancement effect similar to the mechanism operating in jarosite. The significance of the feature for the aqueous alteration history of these asteroids is addressed.

Opportunity, Geologic and Structural Context of Aqueous Alteration in Noachian Outcrops, Marathon Valley and Rim and Endeavour Crater

NASA Technical Reports Server (NTRS)

Crumpler, L. S.; Arvidson, R. E.; Mittlefehldt, D. W.; Jolliff, B. L.; Farrand, W. H.; Fox, V.; Golombek, M. P.

2016-01-01

In its 12th year of exploration and 1600 sols since arrival at the rim of the 22 km-diameter Noachian Endeavour impact crater, Mars Exploration Rover Opportunity traversed from the summit of the western rim segment "Cape Tribulation" to "Marathon Valley", a shallow trough dissecting the rim and the site of strong orbital detection of smectites. In situ analysis of the exposures within Marathon Valley is establishing some of the geologic and geochemical controls on the aqueous alteration responsible for smectite detection known to occur in crater rims throughout Noachian terrains of Mars.

Aqueous geochemistry of low molecular weight hydrocarbons at elevated temperatures and pressures: constraints from mineral buffered laboratory experiments

NASA Astrophysics Data System (ADS)

Seewald, Jeffrey S.

2001-05-01

Organic matter, water, and minerals coexist at elevated temperatures and pressures in sedimentary basins and participate in a wide range of geochemical processes that includes the generation of oil and natural gas. A series of laboratory experiments were conducted at 300 to 350°C and 350 bars to examine chemical interactions involving low molecular weight aqueous hydrocarbons with water and Fe-bearing minerals under hydrothermal conditions. Mineral buffers composed of hematite-magnetite-pyrite, hematite-magnetite, and pyrite-pyrrhotite-magnetite were added to each experiment to fix the redox state of the fluid and the activity of reduced sulfur species. During each experiment the chemical system was externally modified by addition of ethene, ethane, propene, 1-butene, or n-heptane, and variations in the abundance of aqueous organic species were monitored as a function of time and temperature. Results of the experiments indicate that decomposition of aqueous n-alkanes proceeds through a series of oxidation and hydration reactions that sequentially produce alkenes, alcohols, ketones, and organic acids as reaction intermediaries. Organic acids subsequently undergo decarboxylation and/or oxidation reactions to form carbon dioxide and shorter chain saturated hydrocarbons. This alteration assemblage is compositionally distinct from that produced by thermal cracking under anhydrous conditions, indicating that the presence of water and minerals provide alternative reaction pathways for the decomposition of hydrocarbons. The rate of hydrocarbon oxidation decreases substantially under reducing conditions and in the absence of catalytically active aqueous sulfur species. These results represent compelling evidence that the stability of aqueous hydrocarbons at elevated temperatures in natural environments is not a simple function of time and temperature alone. Under the appropriate geochemical conditions, stepwise oxidation represents a mechanism for the decomposition of low molecular weight hydrocarbons and the production of methane-rich ("dry") natural gas. Evaluation of aqueous reaction products generated during the experiments within a thermodynamic framework indicates that alkane-alkene, alkene-ketone, and alkene-alcohol reactions attained metastable thermodynamic equilibrium states. This equilibrium included water and iron-bearing minerals, demonstrating the direct involvement of inorganic species as reactants during organic transformations. The high reactivity of water and iron-bearing minerals suggests that they represent abundant sources of hydrogen and oxygen available for the formation of hydrocarbons and oxygenated alteration products. Thus, variations in elemental kerogen composition may not accurately reflect the timing and extent of hydrocarbon, carbon dioxide, and organic acid generation in sedimentary basins. This study demonstrates that the stabilities of aqueous hydrocarbons are strongly influenced by inorganic sediment composition at elevated temperatures. Incorporation of such interactions into geochemical models will greatly improve prediction of the occurrence of hydrocarbons in natural environments over geologic time.

Effects of Short-Term Thermal Alteration on Organic Matter in Experimentally-Heated Tagish Lake Observed by Raman Spectroscopy

NASA Technical Reports Server (NTRS)

Chan, Q. H. S.; Nakato, A.; Zolensky, M. E.; Nakamura, T.; Kebukawa, Y.

2007-01-01

Carbonaceous chondrites exhibit a wide range of aqueous and thermal alteration characteristics. Examples of the thermally metamorphosed carbonaceous chondrites (TMCCs) include the C2-ung/CM2TIVs Belgica (B)-7904 and Yamato (Y) 86720. The alteration extent is the most complete in these meteorites and thus they are considered typical end-members of TMCCs exhibiting complete dehydration of matrix phyllosilicates [1, 2]. The estimated heating conditions are 10 to 10(sup 3) days at 700 C to 1 to 100 hours at 890 C, i.e. short-term heating induced by impact and/or solar radiation [3]. The chemical and bulk oxygen isotopic compositions of the matrix of the carbonate (CO3)-poor lithology of the Tagish Lake (hereafter Tag) meteorite bears similarities to these TMCCs [4]. We investigated the experimentally-heated Tag with the use of Raman spectroscopy to understand how short-term heating affects the maturity of insoluble organic matter (IOM) in aqueously altered meteorites.

Why is it so difficult to classify Renazzo-type (CR) carbonaceous chondrites? - Implications from TEM observations of matrices for the sequences of aqueous alteration

NASA Astrophysics Data System (ADS)

Abreu, Neyda M.

2016-12-01

A number of different classifications have been proposed for the CR chondrites; this study aims at reconciling these different schemes. Mineralogy-based classification has proved particularly challenging for weakly to moderately altered CRs because incipient mineral replacement and elemental mobilization arising from aqueous alteration only affected the most susceptible primary phases, which are generally located in the matrix. Secondary matrix phases are extremely fine-grained (generally sub-micron) and heterogeneously mixed with primary nebular materials. Compositional and isotopic classification parameters are fraught with confounding factors, such as terrestrial weathering, impact processes, and variable abundance of clasts from different regions of the CR parent body or from altogether different planetary bodies. Here, detailed TEM observations from eighteen FIB sections retrieved from the matrices of nine Antarctic CR chondrites (EET 96259, GRA 95229, GRO 95577, GRO 03116, LAP 02342, LAP 04516, LAP 04720, MIL 07525, and MIL 090001) are presented, representing a range of petrologic types. Amorphous Fe-Mg silicates are found to be the dominant phase in all but the most altered CR chondrite matrices, which still retain significant amounts of these amorphous materials. Amorphous Fe-Mg silicates are mixed with phyllosilicates at the nanometer scale. The ratio of amorphous Fe-Mg silicates to phyllosilicates decreases as: (1) the size of phyllosilicates, (2) abundance of magnetite, and (3) replacement of Fe-Ni sulfides increase. Carbonates are only abundant in the most altered CR chondrite, GRO 95577. Nanophase Fe-Ni metal and tochilinite are present small abundances in most CR matrices. Based on the presence, abundance and size of phyllosilicates with respect to amorphous Fe-Mg silicates, the sub-micron features of CR chondrites have been linked to existing classification sequences, and possible reasons for inconsistencies among classification schemes are discussed.

Moessbauer Mineralogy of Rock, Soil, and Dust at Gusev Crater, Mars: Spirit's Journey through Weakly Altered Olivine Basalt on the Plains and Pervasively Altered Basalt in the Columbia Hills

NASA Technical Reports Server (NTRS)

Morris, R. V.; Klingelhoefer, G.; Schroeder, C.; Rodionov, D. S.; Yen, A.; Ming, D. W.; deSouza, P. A., Jr.; Fleischer, I.; Wdowiak, T.; Gellert, R.;

Mobile Element Studies in Rocks (RAT) from Columbia Hills/West Spur at Gusev

NASA Technical Reports Server (NTRS)

Rao, M. N.; Nyquist, L. E.; Sutton, S. R.; Garrison, D. H.

2007-01-01

Using elemental abundances determined by SPIRIT APX spectrometer on rocks and soils at Gusev Plains and Columbia Hills/ West Spur regions, the Athena Team discussed the aqueous geochemical implications at these sites on Mars. They suggested that these rocks were exposed to variable degrees of aqueous alteration (low to high) at Gusev crater. Earlier, we developed analytical procedures for studying aqueous geochemical behavior of fluids on rocks at Meridiani. In the present study, we apply these methods to rocks at Columbia Hills/West Spur in order to understand the significance of the Gusev rock results in reference to aqueous geochemical processes on Mars . The data analysis procedure is based on treating SO3 ("a") and Cl ("b") as two variables and tracking the relationship between "a" and "b" when the fluids undergo evaporation. This process of evaporation leads to concentration changes in these two elements finally producing salt assemblages on Martian rocks. In some cases on plotting "a"/ "b" versus "b" in salt assemblages, they yield a hyperbolic distribution. The relationship is transformed into a straight line when "a"/"b" is again plotted against 1/"b" in the system. Earlier, we used this procedure in the case of Merdiani rock abrasion tool (RAT) rocks and in this study, we discuss the application of this procedure to Gusev rocks. This study shows that the Gusev Plains rocks were exposed to low SO3/Cl solutions (sulfate-poor) for short period of time (weak interaction), whereas solutions with high SO3/Cl ratios (sulfate-rich) seem to have pervasively interacted with Columbia Hills/ West Spur rocks (strong interaction) at Gusev crater. Our conclusions seem to be consistent with the Mossbauer results given for these rocks

Changes in air flow patterns using surfactants and thickeners during air sparging: bench-scale experiments.

PubMed

Kim, Juyoung; Kim, Heonki; Annable, Michael D

2015-01-01

Air injected into an aquifer during air sparging normally flows upward according to the pressure gradients and buoyancy, and the direction of air flow depends on the natural hydrogeologic setting. In this study, a new method for controlling air flow paths in the saturated zone during air sparging processes is presented. Two hydrodynamic parameters, viscosity and surface tension of the aqueous phase in the aquifer, were altered using appropriate water-soluble reagents distributed before initiating air sparging. Increased viscosity retarded the travel velocity of the air front during air sparging by modifying the viscosity ratio. Using a one-dimensional column packed with water-saturated sand, the velocity of air intrusion into the saturated region under a constant pressure gradient was inversely proportional to the viscosity of the aqueous solution. The air flow direction, and thus the air flux distribution was measured using gaseous flux meters placed at the sand surface during air sparging experiments using both two-, and three-dimensional physical models. Air flow was found to be influenced by the presence of an aqueous patch of high viscosity or suppressed surface tension in the aquifer. Air flow was selective through the low-surface tension (46.5 dyn/cm) region, whereas an aqueous patch of high viscosity (2.77 cP) was as an effective air flow barrier. Formation of a low-surface tension region in the target contaminated zone in the aquifer, before the air sparging process is inaugurated, may induce air flow through the target zone maximizing the contaminant removal efficiency of the injected air. In contrast, a region with high viscosity in the air sparging influence zone may minimize air flow through the region prohibiting the region from de-saturating. Copyright © 2014 Elsevier B.V. All rights reserved.

Potential Cement Phases in Sedimentary Rocks Drilled by Curiosity at Gale Crater, Mars

NASA Technical Reports Server (NTRS)

Rampe, E. B.; Morris, R. V.; Bish, D. L.; Chipera, S. J.; Ming, D. W.; Blake, D. F.; Vaniman, D. T.; Bristow, T. F.; Cavanagh, P.; Farmer, J. D.;

Geology and MER target site characteristics along the southern rim of Isidis Planitia, Mars

USGS Publications Warehouse

Crumpler, L.S.; Tanaka, K.L.

2003-01-01

The southern rim of the Isidis basin contains one of the highest densities of valley networks, several restricted paleolake basins, and the stratigraphically lowest (oldest) terrain on Mars. Geologic mapping in Viking, MGS/MOC, and MOLA data, Odyssey/ THEMIS data, and other multispectral data products supports the presence of extensive fans of debris and sediments deposited along the inner rim of the Isidis basin where large valleys enter the lowlands. Additional processes subsequent to the period of intense fluvial activity, including mass flow analogous to some glacial processes, have contributed to the materials accumulated on the margins of the Isidis basin. These have occurred along preexisting channels and valleys at the termini of major channels where they enter the plains along the highland-lowland boundary. If the abundant valley networks in highland terrains are the result of runoff accompanied by saturated groundwater flow, as has been suggested in previous studies of ancient fluvial highland terrains, then the extreme age and abundance of early valley networks in the Libya Montes highland rocks should have resulted in deposition of materials that record evidence for the long-term presence of water in the form of aqueous alteration of polycrystalline constituents. The material deposited along the basin margin is likely to consist of ancient altered highland rocks in several physical states (weathered, rounded, and angular) exposing both weathered and altered surfaces, and exposures of alteration profiles in fractured faces and unweathered material from rock interiors. Debris fans shed off the southern rim of Isidis Planitia should contain materials that have experienced possible saturated groundwater flow, residence within paleolake basins, and derivative materials deposited during the most fluvially intensive part of Martian geologic history. Many of these materials have also been reworked by ice-related processes. In situ measurements of the ancient crustal materials, in the form of rocks within the debris fans, and the weathered condition of the rocky material are potential sources for mineralogical evidence of climatic conditions in earliest Martian geologic history. The absence of alteration within rocks would, on the other hand, support the hypothesis that fluvial runoff during the earliest history of Mars was geologically brief rather than long-term and that long-term saturated groundwater flow was not present. Determination of the presence or absence of alteration would have corresponding implications for hypotheses requiring the long-term presence of aqueous solutions (i.e., complex organic compounds and life). A proposed MER site along the margin addresses realistic field science objectives of the Mars Exploration Rover mission and the current goals of the Mars Exploration Program. In situ measurements may be important in deriving estimates of the longevity and intensity of past wetter climates. Copyright 2003 by the American Geophysical Union.

Sayama CM2 Chondrite: Fresh but Heavily Altered

NASA Technical Reports Server (NTRS)

Takaoka, N.; Nakamura, T.; Noguchi, T.; Tonui, E.; Gounelle, M.; Zolensky, M. E.; Ebisawa, N.; Osawa, T.; Okazaki, R.; Nagao, K.;

A mild, near-surface aqueous environment on Noachian Mars preserved in ALH84001

NASA Astrophysics Data System (ADS)

Halevy, I.; Fischer, W. W.; Eiler, J. M.

2011-12-01

Despite widespread evidence for liquid water at the surface of Mars during parts of the Noachian epoch, the temperature of early aqueous environments has been impossible to establish, raising questions of whether Mars' surface was ever warmer than today. This has hindered insight into aqueous alteration processes, which, on the basis of orbital spectroscopy, appear to have been prevalent on Noachian Mars. It is important to understand such processes, as they link the observed secondary mineral assemblages to interactions between primary igneous silicates and the surface environment (atmosphere-hydrosphere). We have addressed this problem by determining the precipitation temperatures of secondary carbonate minerals preserved in the oldest known sample of Mars' crust-the meteorite Allan Hills 84001 (ALH84001). Using carbonate 'clumped' isotope thermometry we have found that the carbonates in ALH84001, which are 3.9-4.0 billion years old, formed at a temperature of ~18±4°C. With temperature known, we used the carbon and oxygen isotopic composition of the carbonates, as constrained by both our measurements and previous acid digestion and ion microprobe studies, to develop a model for their formation process and environment. The observed isotopic variation is best explained by carbonate precipitation out of a gradually evaporating, shallow subsurface aqueous solution (e.g. a regolith aquifer) at near-constant temperatures. Furthermore, on the basis of the isotopic composition of the earliest precipitated carbonates in ALH84001, the volatiles from which they formed (H2O and CO2) came not from depth, but from the early Martian surface. The occurrence of carbonates in other SNC meteorites and as a minor component of Martian dust implies that environments analogous to the one we studied may have been important in generating some of the observed secondary mineral assemblages by interaction between Mars' igneous crust and its atmosphere-hydrosphere.

The origin of alteration "orangettes" in Dhofar 019: Implications for the age and aqueous history of the shergottites

NASA Astrophysics Data System (ADS)

Hallis, L. J.; Kemppinen, L.; Lee, M. R.; Taylor, L. A.

2017-12-01

The shergottites are the largest group of Martian meteorites, and the only group that has not been found to contain definitive evidence of Martian aqueous alteration. Given recent reports of current liquid water at the surface of Mars, this study aimed to investigate in detail the possibility of Martian phyllosilicate within shergottite Dhofar 019. Optical and scanning electron microscopy, followed by transmission electron microscopy, confirmed the presence of alteration orangettes, with a layered structure consisting of poorly ordered Mg-phyllosilicate and calcite. These investigations identified maskelynite dissolution, followed by Mg-phyllosilicate and calcite deposition within the dissolution pits, as the method of orangette production. The presence of celestine within the orangette layers, the absence of shock dislocation features within calcite, and the Mg-rich nature of the phyllosilicate, all indicate a terrestrial origin for these features on Dhofar 019.

Interaction processes at the concrete-bentonite interface after 13 years of FEBEX-Plug operation. Part II: Bentonite contact

NASA Astrophysics Data System (ADS)

Fernández, Raúl; Torres, Elena; Ruiz, Ana I.; Cuevas, Jaime; Alonso, María Cruz; García Calvo, José Luis; Rodríguez, Enrique; Turrero, María Jesús

2017-06-01

The in situ FEBEX experiment performed at the URL in Grimsel (Swizerland) was dismantled after 18 years of operation. Interface samples between bentonite and a shotcreted concrete plug that was constructed in a second operational phase have been studied after 13 years of interaction. Mineralogical and geochemical characterization of samples have been performed by XRD, SEM-EDX, TG and FTIR techniques in addition to determinations of major ions by chemical analysis of aqueous extracts, δ18O and δ13C stable isotopes both in concrete paste and bentonite, and exchangeable cations in bentonite. Low mineralogical alteration impact was observed in bentonite that is only affected by a few millimeters. A large accumulation of Mg was observed at the bentonite side of the interface precipitating as silicates in various forms. In addition, heterogeneous carbonation was observed at the interface, but mostly affecting the concrete side. Migration of aqueous species occurred, being the most relevant the diffusion of chloride and sulfate from bentonite to concrete, in agreement with Part I of this study. Chloride advanced more into the concrete, while sulfates reacted to form ettringite, which has an evident alteration impact at the very interface (<0.5 mm rim) within the concrete. The ionic mobility has also redistributed the exchangeable cations in bentonite, increasing the content in Ca2+ and Na+, compensated by a decrease in Mg2+. The results presented in this paper complement those presented in Part I, focusing on the alteration of concrete by the bentonite and the granite groundwater.

Chronic consumption of Hypericum humifusum leaf extracts impairs epididymis spermatozoa characters in association with oxidative stress in adult male Wistar rats.

PubMed

Hammami, Imen; Ali, Ridha Ben; Nahdi, Afef; Kallech-Ziri, Olfa; Boussada, Marwa; El May, Ahmed; El May, Michèle Véronique

2017-09-01

Recently, there has been increasing interest in Hypericum (Hypericaceae) genus. The first part of the present study focused on the phytochemical analysis of the methanolic and aqueous extracts of Hypericum humifusum leaves. The second part of the study investigated the effect of Hypericum humifusum leaf extracts on male reproductive parameters. 30 male rats were grouped into control (1mL/rat, distilled water), treated by 200mg/kg body weight (bw) aqueous extract (A200), 400mg/kg bw aqueous extract (A400), 10mg/kg bw methanolic extract (M10) and 20mg/kg bw methanolic extract (M20) groups. The phytochemical analysis revealed the presence of tannins, flavonoids, steroids, carbohydrates, and phenolic compounds. After thirty-day treatment, body and reproductive organs were weighed. Testes in all rat groups were processed for biochemical assays and histopathological examinations. Epididymis sperm analyses were also performed. Testicular tissue homogenate samples were used for Malondialdehyde (MDA), catalase and superoxide dismutase (SOD) measurements. We showed that Hh extracts induced a severe seminiferous tubular damage with an increase in the percentage of empty seminiferous tubules. Epididymis sperm analysis revealed a significant reduction in density and viability of sperm with alteration of spermatozoa morphology. Also, we found that Hh leaf extracts decreased plasma total cholesterol, HDL-cholesterol and triglycerides levels. These results were associated with an increase of MDA levels and a decrease of catalase and SOD activities in testis tissues. Our finding revealed that chronic consumption of Hh extracts induces disruption of normal spermatogenesis by alteration of sperm density, viability, and morphology. This action may be due to an inhibition of the antioxidant-defense system. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

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

Brown, M. E.; Rhoden, A. R., E-mail: mbrown@caltech.edu, E-mail: Alyssa.Rhoden@jhuapl.edu

We present a medium resolution spectrum of Jupiter's irregular satellite Himalia covering the critical 3 μm spectral region. The spectrum shows no evidence for aqueously altered phyllosilicates, as had been suggested from the tentative detection of a 0.7 μm absorption, but instead shows a spectrum strikingly similar to the C/CF type asteroid 52 Europa. 52 Europa is the prototype of a class of asteroids generally situated in the outer asteroid belt between less distant asteroids which show evidence for aqueous alteration and more distant asteroids which show evidence for water ice. The spectral match between Himalia and this group of asteroids ismore » surprising and difficult to reconcile with models of the origin of the irregular satellites.« less

Hydrated mineral stratigraphy of Ius Chasma, Valles Marineris

USGS Publications Warehouse

Roach, L.H.; Mustard, J.F.; Swayze, G.; Milliken, R.E.; Bishop, J.L.; Murchie, S.L.; Lichtenberg, K.

2010-01-01

New high-resolution spectral and morphologic imaging of deposits on walls and floor of Ius Chasma extend previous geomorphic mapping, and permit a new interpretation of aqueous processes that occurred during the development of Valles Marineris. We identify hydrated mineralogy based on visible-near infrared (VNIR) absorptions. We map the extents of these units with CRISM spectral data as well as morphologies in CTX and HiRISE imagery. Three cross-sections across Ius Chasma illustrate the interpreted mineral stratigraphy. Multiple episodes formed and transported hydrated minerals within Ius Chasma. Polyhydrated sulfate and kieserite are found within a closed basin at the lowest elevations in the chasma. They may have been precipitates in a closed basin or diagenetically altered after deposition. Fluvial or aeolian processes then deposited layered Fe/Mg smectite and hydrated silicate on the chasma floor, postdating the sulfates. The smectite apparently was weathered out of Noachian-age wallrock and transported to the depositional sites. The overlying hydrated silicate is interpreted to be an acid-leached phyllosilicate transformed from the underlying smectite unit, or a smectite/jarosite mixture. The finely layered smectite and massive hydrated silicate units have an erosional unconformity between them, that marks a change in surface water chemistry. Landslides transported large blocks of wallrock, some altered to contain Fe/Mg smectite, to the chasma floor. After the last episode of normal faulting and subsequent landslides, opal was transported short distances into the chasma from a few m-thick light-toned layer near the top of the wallrock, by sapping channels in Louros Valles. Alternatively, the material was transported into the chasma and then altered to opal. The superposition of different types of hydrated minerals and the different fluvial morphologies of the units containing them indicate sequential, distinct aqueous environments, characterized by alkaline, then circum-neutral, and finally very acidic surface or groundwater chemistry. ?? 2009 Elsevier Inc. All rights reserved.

Lunar and Planetary Science XXXV: Mars: Remote Sensing and Terrestrial Analogs

NASA Technical Reports Server (NTRS)

2004-01-01

The session "Mars: Remote Sensing and Terrestrial Analogs" included the following:Physical Meaning of the Hapke Parameter for Macroscopic Roughness: Experimental Determination for Planetary Regolith Surface Analogs and Numerical Approach; Near-Infrared Spectra of Martian Pyroxene Separates: First Results from Mars Spectroscopy Consortium; Anomalous Spectra of High-Ca Pyroxenes: Correlation Between Ir and M ssbauer Patterns; THEMIS-IR Emissivity Spectrum of a Large Dark Streak near Olympus Mons; Geomorphologic/Thermophysical Mapping of the Athabasca Region, Mars, Using THEMIS Infrared Imaging; Mars Thermal Inertia from THEMIS Data; Multispectral Analysis Methods for Mapping Aqueous Mineral Depostis in Proposed Paleolake Basins on Mars Using THEMIS Data; Joint Analysis of Mars Odyssey THEMIS Visible and Infrared Images: A Magic Airbrush for Qualitative and Quantitative Morphology; Analysis of Mars Thermal Emission Spectrometer Data Using Large Mineral Reference Libraries ; Negative Abundance : A Problem in Compositional Modeling of Hyperspectral Images; Mars-LAB: First Remote Sensing Data of Mineralogy Exposed at Small Mars-Analog Craters, Nevada Test Site; A Tool for the 2003 Rover Mini-TES: Downwelling Radiance Compensation Using Integrated Line-Sight Sky Measurements; Learning About Mars Geology Using Thermal Infrared Spectral Imaging: Orbiter and Rover Perspectives; Classifying Terrestrial Volcanic Alteration Processes and Defining Alteration Processes they Represent on Mars; Cemented Volcanic Soils, Martian Spectra and Implications for the Martian Climate; Palagonitic Mars: A Basalt Centric View of Surface Composition and Aqueous Alteration; Combining a Non Linear Unmixing Model and the Tetracorder Algorithm: Application to the ISM Dataset; Spectral Reflectance Properties of Some Basaltic Weathering Products; Morphometric LIDAR Analysis of Amboy Crater, California: Application to MOLA Analysis of Analog Features on Mars; Airborne Radar Study of Soil Moisture at a Mars Analog Site: Tohachi Wash/Little Colorado River; and Antarctic Dry Valleys: Modification of Rocks and Soils and Implications for Mars The Arkaroola Mars Analogue Region, South Australia.

Aqueous processing of organic compounds in carbonaceous asteroids

NASA Astrophysics Data System (ADS)

Trigo-Rodríguez, Josep Maria; Rimola, Albert; Martins, Zita

2015-04-01

There is growing evidence pointing towards a prebiotic synthesis of complex organic species in water-rich undifferentiated bodies. For instance, clays have been found to be associated with complex organic compounds (Pearson et al. 2002; Garvie & Buseck 2007; Arteaga et al. 2010), whereas theoretical calculations have studied the interaction between the organic species and surface minerals (Rimola et al., 2013) as well as surface-induced reactions (Rimola at al. 2007). Now, we are using more detailed analytical techniques to study the possible processing of organic molecules associated with the mild aqueous alteration in CR, CM and CI chondrites. To learn more about these processes we are studying carbonaceous chondrites at Ultra High-Resolution Transmission Electron Microscopy (UHR-TEM). We are particularly interested in the relationship between organics and clay minerals in carbonaceous chondrites (CCs) matrixes (Trigo-Rodríguez et al. 2014, 2015).We want to address two goals: i) identifying the chemical steps in which the organic molecules could have increased their complexity (i.e., surface interaction and catalysis); and ii) studying if the organic matter present in CCs experienced significant processing concomitant to the formation of clays and other minerals at the time in which these planetary bodies experienced aqueous alteration. Here, these two points are preliminarily explored combing experimental results with theoretical calculations based on accurate quantum mechanical methods. References Arteaga O, Canillas A, Crusats J, El-Hachemi Z, Jellison GE, Llorca J, Ribó JM (2010) Chiral biases in solids by effect of shear gradients: a speculation on the deterministic origin of biological homochirality. Orig Life Evol Biosph 40:27-40. Garvie LAJ, Buseck PR (2007) Prebiotic carbon in clays from Orgueil and Ivuna (CI) and Tagish lake (C2 ungrouped) meteorites. Meteorit Planet Sci 42:2111-2117. Pearson VK, Sephton MA, Kearsley AT, Bland AP, Franchi IA, Gilmour A (2002) Clay mineral-organic matter relationships in the early solar system. Meteorit Planet Sci 37:1829-1833. Rimola A, Costa D, Sodupe M, Lambert JF, Ugliengo P (2013) Silica surface features and their role in the adsorption of biomolecules: computational modeling and experiments. Chem Rev 113:4216-4313. Rimola A, Sodupe M, Ugliengo P (2007) Aluminosilicate as promoters for peptide bond formation: an assessment of Bernal's hypothesis by ab initio methods. J Am Chem soc 129:8333-8344 Trigo-Rodríguez JM, Moyano-Cambero CE, Llorca J, Formasier S, Barucci MA, Belskaya I, Martins Z, Rivkin AS, Dotto E, Madiedo JM, Alonso-Azcárate J (2014) UV to far-IR reflectance spectra of carbonaceous chondrites - I. Implications for remote characterization of dark primitive asteroids targeted by sample-return missions. Mon Not R Astron Soc 437:227-240. Trigo-Rodríguez JM, Alonso-Azcárate J, Abad MM, Lee MR (2015) Ultra high resolution Transmission Electron Microscopy of matrix mineral grains in CM chondrites: preaccretionary or parent body aqueous processing? LPI constribution, 46th LPSC, abstract #1198.

A Propensity for n-omega-Amino Acids in Thermally-Altered Antarctic Meteorites

NASA Technical Reports Server (NTRS)

Burton, Aaron S.; Elsila, Jamie E.; Callahan, Michael P.; Martin, Mildred G.; Glavin, Daniel P.; Johnson, Natasha M.; Dworkin, Jason P.

2012-01-01

Carbonaceous meteorites are known to contain a wealth of indigenous organic molecules, including amino acids, which suggests that these meteorites could have been an important source of prebiotic organic material during the origins of life on Earth and possibly elsewhere. We report the detection of extraterrestrial amino acids in thermally-altered type 3 CV and CO carbonaceous chondrites and ureilites recovered from Antarctica. The amino acid concentrations of the thirteen Antarctic meteorites were generally less abundant than in more amino acid-rich CI, CM, and CR carbonaceous chondrites that experienced much lower temperature aqueous alteration on their parent bodies. In contrast to low-temperature aqueously-altered meteorites that show complete structural diversity in amino acids formed predominantly by Strecker-cyanohydrin synthesis, the thermally-altered meteorites studied here are dominated by small, straight-chain, amine terminal (n-omega-amino) amino acids that are not consistent with Strecker formation. The carbon isotopic ratios of two extraterrestrial n-omega-amino acids measured in one of the CV chondrites are consistent with C-13-depletions observed previously in hydrocarbons produced by Fischer-Tropsch type reactions. The predominance of n-omega-amino acid isomers in thermally-altered meteorites hints at cosmochemical mechanisms for the preferential formation and preservation of a small subset of the possible amino acids.

Opaline silica in young deposits on Mars

USGS Publications Warehouse

Milliken, Ralph E.; Swayze, Gregg A.; Arvidson, Raymond E.; Bishop, Janice L; Clark, Roger N.; Ehlmann, Bethany L.; Green, Robert O.; Grotzinger, John P.; Morris, R.V.; Murchie, Scott L.; Mustard, John F.; Weitz, C.

2008-01-01

High spatial and spectral resolution reflectance data acquired by the Mars Reconnaissance Orbiter Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) instrument reveal the presence of H2O- and SiOH-bearing phases on the Martian surface. The spectra are most consistent with opaline silica and glass altered to various degrees, confirming predictions based on geochemical experiments and models that amorphous silica should be a common weathering product of the basaltic Martian crust. These materials are associated with hydrated Fe sulfates, including H3O-bearing jarosite, and are found in finely stratified deposits exposed on the floor of and on the plains surrounding the Valles Marineris canyon system. Stratigraphic relationships place the formation age of these deposits in the late Hesperian or possibly the Amazonian, implying that aqueous alteration continued to be an important and regionally extensive process on Mars during that time.

Protective effects of aqueous fruit extract from Sea Buckthorn (Hippophae rhamnoides L. Spp. Turkestanica) on haloperidol-induced orofacial dyskinesia and neuronal alterations in the striatum.

PubMed

Batool, Farhat; Shah, Asad Hussain; Ahmed, Syed Dilnawaz; Saify, Zafar Saeid; Haleem, Darakhshan Jabeen

2010-08-01

Long-term treatment of haloperidol, a neuroleptic, induces neurodegeneration specifically in the striatum (caudate and putamen), which plays an important role in the development of orofacial dyskinesia, a putative model of tardive dyskinesia (TD). This study investigated the protective effects of a concomitant treatment of aqueous fruit extract of Sea buckthorn (Hippophae rhamnoides L. spp. Turkestanica) (SBT-FE) (40 mg/kg, orally) plus haloperidol (3.0 mg/kg, ip) administration on an animal model of TD and on striatal neuronal alterations. Rats received daily haloperidol (3.0 mg/kg ip) and saline injections for 15 days. Seven-day posttreatment, aqueous SBT-FE (40 mg/kg) was administered daily via a feeding tube. Hypolocomotive effects (home cage activity, exploratory activity, catalepsy, and vacuous chewing movements) were monitored consecutively in each group. On the last day of the experiments, changes in extracellular levels of striatal dopamine (DA), dihydroxyphenyl acetic acid (DOPAC) and homovanillic acid (HVA) were determined by HPLC-EC. Aqueous SBT-FE attenuated haloperidol-induced VCMs after second week of treatment and locomotor activity was greater in rats treated with SBT-FE compared with the controls. The results indicate that DA and HVA levels in the striatum were significantly (P <.01) altered in rats given SBT-FE before injections of haloperidol. Hippophae rhamnoides fruit extract has a protective role against haloperidol-induced orofacial dyskinesia. Consequently, use of Hippophae rhamnoides as a possible therapeutic agent for the treatment of tardive dyskinesia should be considered.

Fluids During Diagenesis and Sulfate Vein Formation in Sediments at Gale Crater, Mars

NASA Technical Reports Server (NTRS)

Schwenzer, S. P.; Bridges, J. C.; Weins, R. C.; Conrad, P. G.; Kelley, S. P.; Leveille, R.; Mangold, N.; Martin-Torres, J.; McAdam, A.; Newsom, H.;

Evidence for organic synthesis in high temperature aqueous media - facts and prognosis

NASA Technical Reports Server (NTRS)

Simoneit, Bernd R. T.

1995-01-01

Hydrothermal systems are common along the active tectonic areas of the earth. Potential sites being studied for organic matter alteration and possible organic synthesis are spreading ridges, off-axis systems, back-arc activity, hot spots, volcanism, and subduction. Organic matter alteration, primarily reductive and generally from immature organic detritus, occurs in these high temperature and rapid fluid flow hydrothermal regimes. Hot circulating water (temperature range - warm to greater than 400 C) is responsible for these molecular alterations, expulsion and migration. Compounds that are obviously synthesized are minor components because they are generally masked by the pyrolysis products formed from contemporary natural organic precursors. The reactivity of organic compounds in hot water (200-350 C) has been studied in autoclaves, and supercritical water as a medium for chemistry has also been evaluated. This high temperature aqueous organic chemistry and the strong reducing conditions of the natural systems suggest this as an important route to produce organic compounds on the primitive earth. Thus a better understanding of the potential syntheses of organic compounds in hydrothermal systems will require investigations of the chemistry of condensation, autocatalysis, catalysis and hydrolysis reactions in aqueous mineral buffered systems over a range of temperatures from warm to greater than 400 C.

SOLVENT EXTRACTION PROCESS

DOEpatents

Jonke, A.A.

1957-10-01

In improved solvent extraction process is described for the extraction of metal values from highly dilute aqueous solutions. The process comprises contacting an aqueous solution with an organic substantially water-immiscible solvent, whereby metal values are taken up by a solvent extract phase; scrubbing the solvent extract phase with an aqueous scrubbing solution; separating an aqueous solution from the scrubbed solvent extract phase; and contacting the scrubbed solvent phase with an aqueous medium whereby the extracted metal values are removed from the solvent phase and taken up by said medium to form a strip solution containing said metal values, the aqueous scrubbing solution being a mixture of strip solution and an aqueous solution which contains mineral acids anions and is free of the metal values. The process is particularly effective for purifying uranium, where one starts with impure aqueous uranyl nitrate, extracts with tributyl phosphate dissolved in carbon tetrachloride, scrubs with aqueous nitric acid and employs water to strip the uranium from the scrubbed organic phase.

Mineralogical, crystallographic and redox features of the earliest stages of fluid alteration in CM chondrites

NASA Astrophysics Data System (ADS)

Pignatelli, Isabella; Marrocchi, Yves; Mugnaioli, Enrico; Bourdelle, Franck; Gounelle, Matthieu

2017-07-01

The CM chondrites represent the largest group of hydrated meteorites and span a wide range of conditions, from less altered (i.e., CM2) down to heavily altered (i.e., CM1). The Paris chondrite is considered the least altered CM and thus enables the earliest stages of aqueous alteration processes to be deciphered. Here, we report results from a nanoscale study of tochilinite/cronstedtite intergrowths (TCIs) in Paris-TCIs being the emblematic secondary mineral assemblages of CM chondrites, formed from the alteration of Fe-Ni metal beads (type-I TCIs) and anhydrous silicates (type-II TCIs). We combined high-resolution transmission electron microscopy, scanning transmission X-ray microscopy and electron diffraction tomography to characterize the crystal structure, crystal chemistry and redox state of TCIs. The data obtained are useful to reconstruct the alteration conditions of Paris and to compare them with those of other meteorites. Our results show that tochilinite in Paris is characterized by a high hydroxide layer content (n = 2.1-2.2) regardless of the silicate precursors. When examined alongside other CMs, it appears that the hydroxide layer and iron contents of tochilinites correlate with the degree of alteration experienced by the chondrites. The Fe3+/ΣFe ratios of TCIs are high: 8-15% in tochilinite, 33-60% in cronstedtite and 70-80% in hydroxides. These observations suggest that alteration of CM chondrites took place under oxidizing conditions that could have been induced by significant H2 release during serpentinization. Similar results were recently reported in CR chondrites (Le Guillou et al., 2015), suggesting that the process(es) controlling the redox state of the secondary mineral assemblages were quite similar in the CM and CR parent bodies despite the different alteration conditions. According to our mineralogical and crystallographic survey, the formation of TCIs in Paris occurred at temperatures lower than 100 °C, under neutral, slightly alkaline conditions that favored the formation of both tochilinite and cronstedtite. During the course of alteration, the reduction in sulfur activity and/or the decrease of temperature prevented tochilinite crystallization and favoured the formation of cronstedtite and iron hydroxides. We suggest that iron hydroxides probably formed as ferrihydrite and then progressively converted to goethite between 50° and 80 °C, a temperature range that is also favorable for cronstedtite formation. The presence of cronstedtite plays a key role in the reconstruction of the alteration history, demonstrating that the alteration of Paris took place by way of serpentinization processes similar to those described on the Earth.

Diagenesis Along Fractures in an Eolian Sandstone, Gale Crater, Mars

NASA Technical Reports Server (NTRS)

Ming, D. W.; Yen, A. S.; Rampe, E. B.; Grotzinger, J. P.; Blake, D. F.; Bristow, T. F.; Chipera, S. J.; Downs, R.; Morris, R. V.; Morrison, S. M.;

Colors and Compositional Characteristics of Kuiper Belt Objects and Centaurs

NASA Astrophysics Data System (ADS)

Lederer, S. M.; Vilas, F.; Jarvis, K. S.; French, L.

2001-11-01

We present a study designed by Painter et al. (DPS 2000) to search for evidence of aqueous alteration in the surface material of solar system objects. Using VRI broadband photometry, we will search for the presence of the 0.7 um absorption feature (indicative of Fe-bearing hydrated silicates) in KBOs and Centaurs. Vilas (Icarus 111, 1994) found a strong correlation between the presence of the 0.7-um feature in low-albedo asteroids with solar-like colors and the 3-um water of hydration feature, indicative of phyllosilicates. Recent work by Howell et al. (LPSC, 2001) confirms that the presence of the 0.7 um feature in low-albedo asteroids definitely indicates the presence of the 3.0-um water of hydration absorption feature, suggesting the action of aqueous alteration in asteroids. In addition, Feierberg et al. (Icarus 63, 1985) showed that when the U - B color difference is > 0.12 in ECAS photometry, the 3.0-um absorption feature is often present in low albedo asteroids. Therefore, if the U-B color difference is > 0.12 and the 0.7-um feature is present in UBVRI reflectance photometry, water of hydration is implied in KBOs and Centaurs. We pursue these studies based on the mixed flat or steeply reddened photometry of these objects: Water ice has been identified in near-IR dark, flat spectra of some Centaurs, providing a source for the action of aqueous alteration. The complex collisional history proposed for these objects suggests a potential source of heating that would melt water ice, providing a mechanism for aqueous alteration to occur. Finally, we will use BVR photometry to determine the B-V and V-R colors, as has been done by Tegler and Romanishin (Nature, 407). We will compare our results with colors of KBOs and Centaurs published in the literature. This research was supported by the National Research Council and the NASA Planetary Astronomy Program.

I-Xe dating of aqueous alteration in the CI chondrite Orgueil: I. Magnetite and ferromagnetic separates

NASA Astrophysics Data System (ADS)

Pravdivtseva, O.; Krot, A. N.; Hohenberg, C. M.

2018-04-01

The I-Xe system was studied in a ferromagnetic sample separated from the Orgueil CI carbonaceous chondrite with a hand-held magnet and in two magnetite samples, one chemically separated before and the other one after neutron irradiation. This work was done in order to investigate the effects of chemical separation by LiCl and NaOH on the I-Xe system in magnetite. Our test demonstrated that the chemical separation of magnetite before irradiation using either LiCl or NaOH, or both, does not contaminate the sample with iodine and thus cannot lead to erroneous I-Xe ages due to introduction of uncorrelated 128∗Xe. The I-Xe ages of two Orgueil magnetite samples are mutually consistent within experimental uncertainties and, when normalized to an absolute time scale with the reevaluated Shallowater aubrite standard, place the onset of aqueous alteration on the CI parent body at 4564.3 ± 0.3 Ma, 2.9 ± 0.3 Ma after formation of the CV Ca-AI-rich inclusions (CAIs). The I-Xe age of the ferromagnetic Orgueil separate is 3.4 Ma younger, corresponding to a closure of the I-Xe system at 4560.9 ± 0.2 Ma. These and previously published I-Xe data for Orgueil (Hohenberg et al., 2000) indicate that aqueous alteration on the CI parent body lasted for at least 5 Ma. Although the two magnetite samples gave indistinguishable I-Xe ages, their temperature release profiles differed. One of the two Orgueil magnetites released less radiogenic Xe than the other, 80% of it corresponding to the low-temperature peak of the release profile, compared to only 6% in case of the second Orgueil magnetite sample. This could be due to the difference in iodine trapping efficiencies for magnetite grains of different morphologies. Alternatively, the magnetite grains with the lower radiogenic Xe concentrations may have formed at a later stage of alteration when iodine in an aqueous solution was depleted.

Ultrasensitive molecular detection using thermal conductance of a hydrophobic gold-water interface.

PubMed

Green, Andrew J; Alaulamie, Arwa A; Baral, Susil; Richardson, Hugh H

2013-09-11

The thermal conductance from a hydrophobic gold aqueous interface is measured with increasing solute concentration. A small amount of aqueous solute molecules (1 solute molecule in 550 water molecules) dramatically increases the heat dissipation into the surrounding liquid. This result is consistent with a thermal conductance that is limited by an interface interaction where minority aqueous components significantly alter the surface properties and heat transport through the interface. The increase in heat dissipation can be used to make an extremely sensitive molecular detector that can be scaled to give single molecule detection without amplification or utilizing fluorescence labels.

Meteoric water alteration of soil and landscapes at Meridiani Planum, Mars

NASA Astrophysics Data System (ADS)

Amundson, Ronald

2018-04-01

The geomorphology and geochemistry data gathered by the MER Opportunity at Meridiani Planum is a rich data set relevant to soil research on Mars. Many of the data, particularly with respect to outcrops at Victoria Crater, have been only partially analyzed. Here, the previously published geochemical profile of Endurance Crater is compared to that of Victoria Crater, to understand aspects of the post-depositional aqueous and chemical alteration of the Meridiani land surface. The landsurface bears cracking patterns similar to those produced by multiple episodes of wetting and drying in expansive materials on Earth. The geochemical profiles at both craters are nearly identical, suggesting (using mass balance methods) that a very chemically homogenous sedimentary deposit has been engulfed by the apparent surficial addition of S, Cl, and Br (and associated cations) since exposure to the atmosphere. The chemistry and mineralogy at both locations is one where the most insoluble of the added components resides near the land surface (Ca sulfates), and the more soluble components are concentrated at greater depths in a vertical pattern consistent with their solubility in water. The profiles, when compared to those on Earth (and to physical constraints), are most similar those generated by the downward movement of meteoric water. When this aqueous alteration and soil formation occurred is not well constrained, but the processes occurred between late Noachian (?) to late Amazonian times. The exposure of the Victoria crater walls, which occurred likely less than 107 y ago (late Amazonian), shows the accumulation of dust as well as evidence for aqueous concentration of NaBr and/or CaBr, possibly by deliquescence. By direct comparison to Earth, the regional soil at Meridiani Planum is a Typic Petrogypsid (a sulfate cemented arid soil), bearing similarities to very ancient soils formed in the Atacama Desert of Chile. The amount of water required to produce the soils ranges from a very low (and physically unlikely) quantity of 2-4 m, to possibly (and more likely) kilometers of water that were added in small individual increments over long spans of geological time.

The Spirit Rover's Athena science investigation at Gusev Crater, Mars

NASA Technical Reports Server (NTRS)

Squyres, S. W.; Arvidson, R. E.; Bell, J. F., III; Brueckner, J.; Cabrol, N. A.; Calvin, W.; Carr, M. H.; Christensen, P. R.; Clark, B. C.; Crumpler, L.;

The Spirit Rover's Athena science investigation at Gusev crater, Mars

USGS Publications Warehouse

Squyres, S. W.; Arvidson, R. E.; Bell, J.F.; Brückner, J.; Cabrol, N.A.; Calvin, W.; Carr, M.H.; Christensen, P.R.; Clark, B. C.; Crumpler, L.; Des Marais, D.J.; D'Uston, C.; Economou, T.; Farmer, J.; Farrand, W.; Folkner, W.; Golombek, M.; Gorevan, S.; Grant, J. A.; Greeley, R.; Grotzinger, J.; Haskin, L.; Herkenhoff, K. E.; Hviid, S.; Johnson, J.; Klingelhofer, G.; Knoll, A.; Landis, G.; Lemmon, M.; Li, R.; Madsen, M.B.; Malin, M.C.; McLennan, S.M.; McSween, H.Y.; Ming, D. W.; Moersch, J.; Morris, R.V.; Parker, T.; Rice, J. W.; Richter, L.; Rieder, R.; Sims, M.; Smith, M.; Smith, P.; Soderblom, L.A.; Sullivan, R.; Wanke, H.; Wdowiak, T.; Wolff, M.; Yen, A.

2004-01-01

The Mars Exploration Rover Spirit and its Athena science payload have been used to investigate a landing site in Gusev crater. Gusev is hypothesized to be the site of a former take, but no clear evidence for lacustrine sedimentation has been found to date. Instead, the dominant lithology is basalt, and the dominant geologic processes are impact events and eolian transport. Many rocks exhibit coatings and other characteristics that may be evidence for minor aqueous alteration. Any lacustrine sediments that may exist at this location within Gusev apparently have been buried by lavas that have undergone subsequent impact disruption.

Geology of McLaughlin Crater, Mars: A Unique Lacustrine Setting with Implications for Astrobiology

NASA Technical Reports Server (NTRS)

Michalski, J. R.; Niles, P. B.; Rogers, A. D.; Johnson, S. S.; Ashley, J. W.; Golombek, M. P.

2016-01-01

McLaughlin crater is a 92-kmdiameter Martian impact crater that contained an ancient carbonate- and clay mineral-bearing lake in the Late Noachian. Detailed analysis of the geology within this crater reveals a complex history with important implications for astrobiology [1]. The basin contains evidence for, among other deposits, hydrothermally altered rocks, delta deposits, deep water (>400 m) sediments, and potentially turbidites. The geology of this basin stands in stark contrast to that of some ancient basins that contain evidence for transient aqueous processes and airfall sediments (e.g. Gale Crater [2-3]).

Coordinated Isotopic and Mineral Characterization of Highly Fractionated 18O-Rich Silicates in the Queen Alexandra Range 99177 CR3 Chondrite

NASA Technical Reports Server (NTRS)

Nguyen, A. N.; Keller, L. P.; Messenger, S.; Rahman, Z.

2016-01-01

Carbonaceous chondrites contain a mixture of solar system condensates, pre-solar grains, and primitive organic matter. Each of these materials record conditions and processes in different regions of the solar nebula, on the meteorite parent body, and beyond the solar system. Oxygen isotopic studies of meteorite components can trace interactions of distinct oxygen isotopic reservoirs in the early solar system and secondary alteration processes. The O isotopic compositions of the earliest solar system condensates fall along a carbonaceous chondrite anhydrous mineral (CCAM) line of slope approximately 1 in a plot of delta 17O against delta 18O. This trend is attributed to mixing of material from 16O-poor and 16O-rich reservoirs. Secondary processing can induce mass-dependent fractionation of the O isotopes, shifting these compositions along a line of slope approximately 0.52. Substantial mass-dependent fractionation of O isotopes has been observed in secondary minerals in CAIs, calcite, and FUN inclusions. These fractionations were caused by significant thermal or aqueous alteration. We recently reported the identification of four silicate grains with extremely fractionated O isotopic ratios (delta 18O equals 37 - 55 per mille) in the minimally altered CR3 chondrite QUE 99177. TEM analysis of one grain indicates it is a nebular condensate that did not experience substantial alteration. The history of these grains is thus distinct from those of the aforementioned fractionated materials. To constrain the origin of the silicate grains, we conducted further Mg and Fe isotopic studies and TEM analyses of two grains.

Molecular structure of dextran sulphate sodium in aqueous environment

NASA Astrophysics Data System (ADS)

Yu, Miao; Every, Hayley A.; Jiskoot, Wim; Witkamp, Geert-Jan; Buijs, Wim

2018-03-01

Here we propose a 3D-molecular structural model for dextran sulphate sodium (DSS) in a neutral aqueous environment based on the results of a molecular modelling study. The DSS structure is dominated by the stereochemistry of the 1,6-linked α-glucose units and the presence of two sulphate groups on each α-glucose unit. The structure of DSS can be best described as a helix with various patterns of di-sulphate substitution on the glucose rings. The presence of a side chain does not alter the 3D-structure of the linear main chain much, but affects the overall spatial dimension of the polymer. The simulated polymers have a diameter similar to or in some cases even larger than model α-hemolysin nano-pores for macromolecule transport in many biological processes, indicating a size-limited translocation through such pores. All results of the molecular modelling study are in line with previously reported experimental data. This study establishes the three-dimensional structure of DSS and summarizes the spatial dimension of the polymer, serving as the basis for a better understanding on the molecular level of DSS-involved electrostatic interaction processes with biological components like proteins and cell pores.

Aqueous Processing for Printed Organic Electronics: Conjugated Polymers with Multistage Cleavable Side Chains

PubMed Central

2017-01-01

The ability to process conjugated polymers via aqueous solution is highly advantageous for reducing the costs and environmental hazards of large scale roll-to-roll processing of organic electronics. However, maintaining competitive electronic properties while achieving aqueous solubility is difficult for several reasons: (1) Materials with polar functional groups that provide aqueous solubility can be difficult to purify and characterize, (2) many traditional coupling and polymerization reactions cannot be performed in aqueous solution, and (3) ionic groups, though useful for obtaining aqueous solubility, can lead to a loss of solid-state order, as well as a screening of any applied bias. As an alternative, we report a multistage cleavable side chain method that combines desirable aqueous processing attributes without sacrificing semiconducting capabilities. Through the attachment of cleavable side chains, conjugated polymers have for the first time been synthesized, characterized, and purified in organic solvents, converted to a water-soluble form for aqueous processing, and brought through a final treatment to cleave the polymer side chains and leave behind the desired electronic material as a solvent-resistant film. Specifically, we demonstrate an organic soluble polythiophene that is converted to an aqueous soluble polyelectrolyte via hydrolysis. After blade coating from an aqueous solution, UV irradiation is used to cleave the polymer’s side chains, resulting in a solvent-resistant, electroactive polymer thin film. In application, this process results in aqueous printed materials with utility for solid-state charge transport in organic field effect transistors (OFETs), along with red to colorless electrochromism in ionic media for color changing displays, demonstrating its potential as a universal method for aqueous printing in organic electronics. PMID:28979937

Aqueous Processing for Printed Organic Electronics: Conjugated Polymers with Multistage Cleavable Side Chains.

PubMed

Schmatz, Brian; Yuan, Zhibo; Lang, Augustus W; Hernandez, Jeff L; Reichmanis, Elsa; Reynolds, John R

2017-09-27

The ability to process conjugated polymers via aqueous solution is highly advantageous for reducing the costs and environmental hazards of large scale roll-to-roll processing of organic electronics. However, maintaining competitive electronic properties while achieving aqueous solubility is difficult for several reasons: (1) Materials with polar functional groups that provide aqueous solubility can be difficult to purify and characterize, (2) many traditional coupling and polymerization reactions cannot be performed in aqueous solution, and (3) ionic groups, though useful for obtaining aqueous solubility, can lead to a loss of solid-state order, as well as a screening of any applied bias. As an alternative, we report a multistage cleavable side chain method that combines desirable aqueous processing attributes without sacrificing semiconducting capabilities. Through the attachment of cleavable side chains, conjugated polymers have for the first time been synthesized, characterized, and purified in organic solvents, converted to a water-soluble form for aqueous processing, and brought through a final treatment to cleave the polymer side chains and leave behind the desired electronic material as a solvent-resistant film. Specifically, we demonstrate an organic soluble polythiophene that is converted to an aqueous soluble polyelectrolyte via hydrolysis. After blade coating from an aqueous solution, UV irradiation is used to cleave the polymer's side chains, resulting in a solvent-resistant, electroactive polymer thin film. In application, this process results in aqueous printed materials with utility for solid-state charge transport in organic field effect transistors (OFETs), along with red to colorless electrochromism in ionic media for color changing displays, demonstrating its potential as a universal method for aqueous printing in organic electronics.

Phyllosilicate diversity and past aqueous activity revealed at Mawrth Vallis, Mars

USGS Publications Warehouse

Bishop, J.L.; Dobrea, E.Z.N.; McKeown, N.K.; Parente, M.; Ehlmann, B.L.; Michalski, J.R.; Milliken, R.E.; Poulet, F.; Swayze, G.A.; Mustard, J.F.; Murchie, S.L.; Bibring, J.-P.

2008-01-01

Observations by the Mars Reconnaissance Orbiter/Compact Reconnaissance Imaging Spectrometer for Mars in the Mawrth Vallis region show several phyllosilicate species, indicating a wide range of past aqueous activity. Iron/magnesium (Fe/Mg)-smectite is observed in light-toned outcrops that probably formed via aqueous alteration of basalt of the ancient cratered terrain. This unit is overlain by rocks rich in hydrated silica, montmorillonite, and kaolinite that may have formed via subsequent leaching of Fe and Mg through extended aqueous events or a change in aqueous chemistry. A spectral feature attributed to an Fe2+ phase is present in many locations in the Mawrth Vallis region at the transition from Fe/Mg-smectite to aluminum/silicon (Al/Si)-rich units. Fe2+-bearing materials in terrestrial sediments are typically associated with microorganisms or changes in pH or cations and could be explained here by hydrothermal activity. The stratigraphy of Fe/Mg-smectite overlain by a ferrous phase, hydrated silica, and then Al-phyllosilicates implies a complex aqueous history.

Non-aqueous solution preparation of doped and undoped lixmnyoz

DOEpatents

Boyle, Timothy J.; Voigt, James A.

1997-01-01

A method for generation of phase-pure doped and undoped Li.sub.x Mn.sub.y O.sub.z precursors. The method of this invention uses organic solutions instead of aqueous solutions or nonsolution ball milling of dry powders to produce phase-pure precursors. These precursors can be used as cathodes for lithium-polymer electrolyte batteries. Dopants may be homogeneously incorporated to alter the characteristics of the powder.

REDISTRIBUTION OF ALKALINE ELEMENTS IN ASSOCIATION WITH AQUEOUS ACTIVITY IN THE EARLY SOLAR SYSTEM

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

Hidaka, Hiroshi; Higuchi, Takuya; Yoneda, Shigekazu, E-mail: hidaka@hiroshima-u.ac.jp, E-mail: s-yoneda@kahaku.go.jp

2015-12-10

It is known that the Sayama meteorite (CM2) shows an extensive signature for aqueous alteration on the meteorite parent body, and that most of the primary minerals in the chondrules are replaced with phyllosilicates as the result of the aqueous alteration. In this paper, it is confirmed from the observation of two-dimensional Raman spectra that a part of olivine in a chondrule collected from the Sayama chondrite is serperntinized. Ion microprobe analysis of the chondrule showed that alkaline elements such as Rb and Cs are heterogeneously redistributed in the chondrule. The result of higher Rb and Cs contents in serpentinizedmore » phases in the chondrule rather than in other parts suggested the selective adsorption of alkaline elements into the serpentine in association with early aqueous activity on the meteorite parent body. Furthermore Ba isotopic analysis provided variations of {sup 135}Ba/{sup 138}Ba and {sup 137}Ba/{sup 138}Ba in the chondrule. This result was consistent with our previous isotopic data suggesting isotopic evidence for the existence of the presently extinct nuclide {sup 135}Cs in the Sayama meteorite, but the abundance of {sup 135}Cs in the solar system remains unclear because of large analytical uncertainties.« less

Esperance: Multiple episodes of aqueous alteration involving fracture fills and coatings at Matijevic Hill, Mars

USGS Publications Warehouse

Clark, Benton C.; Morris, Richard V.; Herkenhoff, Kenneth E.; Farrand, William H.; Gellert, Ralf; Jolliff, Bradley L.; Arvidson, Raymond E.; Squyres, Steven W.; Mittelfehldt, David W.; Ming, Douglas W.; Yen, Albert S.

2016-01-01

In the search for evidence of past aqueous activity by the Mars Exploration Rover Opportunity, fracture-filling veins and rock coatings are prime candidates for exploration. At one location within a segment of remaining rim material surrounding Endeavour Crater, a set of “boxwork” fractures in an outcrop called Esperance are filled by a bright, hydrated, and highly siliceous (SiO2 ~ 66 wt%) material, which has overall a montmorillonite-like chemical composition. This material is partially covered by patches of a thin, dark coating that is sulfate-rich (SO3 ~ 21 wt%) but also contains significant levels of Si, Fe, Ca, and Mg. The simultaneous presence of abundant S, Si, and Fe indicates significant mineralogical complexity within the coating. This combination of vein and coating compositions is unlike previous analyses on Mars. Both materials are heterogeneously eroded, presumably by eolian abrasion. The evidence indicates at least two separate episodes of solute precipitation from aqueous fluids at this location, possibly widely separated in time. In addition to the implications for multiple episodes of alteration at the surface of the planet, aqueous chemical environments such as these would have been habitable at the time of their formation and are also favorable for preservation of organic material.

Hydrothermal alteration and diagenesis of terrestrial lacustrine pillow basalts: Coordination of hyperspectral imaging with laboratory measurements

NASA Astrophysics Data System (ADS)

Greenberger, Rebecca N.; Mustard, John F.; Cloutis, Edward A.; Mann, Paul; Wilson, Janette H.; Flemming, Roberta L.; Robertson, Kevin M.; Salvatore, Mark R.; Edwards, Christopher S.

2015-12-01

We investigate an outcrop of ∼187 Ma lacustrine pillow basalts of the Talcott Formation exposed in Meriden, Connecticut, USA, focusing on coordinated analyses of one pillow lava to characterize the aqueous history of these basalts in the Hartford Basin. This work uses a suite of multidisciplinary measurements, including hyperspectral imaging, other spectroscopic techniques, and chemical and mineralogical analyses, from the microscopic scale up to the scale of an outcrop. The phases identified in the sample are albite, large iron oxides, and titanite throughout; calcite in vesicles; calcic clinopyroxene, aegirine, and Fe/Mg-bearing clay in the rind; and fine-grained hematite and pyroxenes in the interior. Using imaging spectroscopy, the chemistry and mineralogy results extend to the hand sample and larger outcrop. From all of the analyses, we suggest that the pillow basalts were altered initially after emplacement, either by heated lake water or magmatic fluids, at temperatures of at least 400-600 °C, and the calcic clinopyroxenes and aegirine identified in the rind are a preserved record of that alteration. As the hydrothermal system cooled to slightly lower temperatures, clays formed in the rind, and, during this alteration, the sample oxidized to form hematite in the matrix of the interior and Fe3+ in the pyroxenes in the rind. During the waning stages of the hydrothermal system, calcite precipitated in vesicles within the rind. Later, diagenetic processes albitized the sample, with albite replacing plagioclase, lining vesicles, and accreting onto the exterior of the sample. This albitization or Na-metasomatism occurred when the lake within the Hartford Basin evaporated during a drier past climatic era, resulting in Na-rich brines. As Ca-rich plagioclase altered to albite, Ca was released into solution, eventually precipitating as calcite in previously-unfilled vesicles, dominantly in the interior of the pillow. Coordinated analyses of this sample permit identification of the alteration phases and help synthesize the aqueous history of pillow lavas of the Talcott Formation. These results are also relevant to Mars, where volcanically-resurfaced open basin lakes have been found, and this Hartford Basin outcrop may be a valuable analog for any potential volcano-lacustrine interactions. The results can also help to inform the utility and optimization of potentially complementary, synergistic, and uniquely-suited techniques for characterization of hydrothermally-altered terrains.

Thermodynamics of water structural reorganization due to geometric confinement

NASA Astrophysics Data System (ADS)

Stroberg, Wylie; Lichter, Seth

2015-03-01

Models of aqueous solvation have successfully quantified the behavior of water near convex bodies. However, many important processes occurring in aqueous solution involve interactions between solutes and surfaces with complicated non-convex geometries. Examples include the folding of proteins, hydrophobic association of solutes, ligand-receptor binding, and water confined within nanotubes and pores. For these geometries, models for solvation of convex bodies fail to account for the added interactions associated with structural confinement. Due to water's propensity to form networks of hydrogen bonds, small alterations to the confining geometry can induce large structural rearrangement within the water. We perform systematic Monte Carlo simulations of water confined to cylindrical cavities of varying aspect ratio to investigate how small geometric changes to the confining geometry may cause large changes to the structure and thermodynamic state of water. Using the Wang-Landau algorithm, we obtain free energies, enthalpies, entropies, and heat capacities across a broad range of temperatures, and show how these quantities are influenced by the structural rearrangement of water molecules due to geometric perturbations.

Workshop on Parent-Body and Nebular Modification of Chondritic Materials

NASA Technical Reports Server (NTRS)

Krot, A. N. (Editor); Zolensky, M. E. (Editor); Scott, E. R. D. (Editor)

1997-01-01

The purpose of the workshop was to advance our understanding of solar nebula and asteroidal processes from studies of modification features in chondrites and interplanetary dust particles. As reflected in the program contained in this volume, the workshop included five regular sessions, a summary session, and a poster session. Twenty-three posters and 42 invited and contributed talks were presented. Part 1 of this report contains the abstracts of these presentations. The focus of the workshop included: (1) mineralogical, petrologic, chemical, and isotopic observations of the alteration mineralogy in interplanetary dust particles, ordinary and carbonaceous chondrites, and their components (Ca-Al-rich inclusions, chondrules, and matrix) to constrain the conditions and place of alteration; (2) sources of water in chondrites; (3) the relationship between aqueous alteration and thermal metamorphism; (4) short-lived radionuclides, AI-26, Mn-53, and I-129, as isotopic constraints on timing of alteration; (5) experimental and theoretical modeling of alteration reactions; and (6) the oxidation state of the solar nebula. There were approximately 140 participants at the workshop, probably due in part to the timeliness of the workshop goals and the workshop location. In the end few new agreements were achieved between warring factions, but new research efforts were forged and areas of fruitful future exploration were highlighted. Judged by these results, the workshop was successful.

Modeling Interfacial Glass-Water Reactions: Recent Advances and Current Limitations

DOE PAGES

Pierce, Eric M.; Frugier, Pierre; Criscenti, Louise J.; ...

2014-07-12

Describing the reactions that occur at the glass-water interface and control the development of the altered layer constitutes one of the main scientific challenges impeding existing models from providing accurate radionuclide release estimates. Radionuclide release estimates are a critical component of the safety basis for geologic repositories. The altered layer (i.e., amorphous hydrated surface layer and crystalline reaction products) represents a complex region, both physically and chemically, sandwiched between two distinct boundaries pristine glass surface at the inner most interface and aqueous solution at the outer most interface. Computational models, spanning different length and time-scales, are currently being developed tomore » improve our understanding of this complex and dynamic process with the goal of accurately describing the pore-scale changes that occur as the system evolves. These modeling approaches include geochemical simulations [i.e., classical reaction path simulations and glass reactivity in allowance for alteration layer (GRAAL) simulations], Monte Carlo simulations, and Molecular Dynamics methods. Finally, in this manuscript, we discuss the advances and limitations of each modeling approach placed in the context of the glass-water reaction and how collectively these approaches provide insights into the mechanisms that control the formation and evolution of altered layers.« less

Membrane separation for non-aqueous solution

NASA Astrophysics Data System (ADS)

Widodo, S.; Khoiruddin; Ariono, D.; Subagjo; Wenten, I. G.

2018-01-01

Membrane technology has been widely used in a number of applications competing with conventional technologies in various ways. Despite the enormous applications, they are mainly used for the aqueous system. The use of membrane-based processes in a non-aqueous system is an emerging area. This is because developed membranes are still limited in separations involving aqueous solution which show several drawbacks when implemented in a non-aqueous system. The purpose of this paper is to provide a review of the current application of membrane processes in non-aqueous solutions, such as mineral oil treatment, vegetable oil processing, and organic solvent recovery. Developments of advanced membrane materials for the non-aqueous solutions such as super-hydrophobic and organic solvent resistant membranes are reviewed. In addition, challenges and future outlook of membrane separation for the non-aqueous solution are discussed.

JOVE/NASA Funded Search for Aqueously Altered Minor Planets Provides Undergraduates with Valuable Research Experience

NASA Astrophysics Data System (ADS)

Watkins, L.; Leake, M.; Kilgard, R.; Semmes, K.; Alpert, A.

1997-12-01

A Joint Venture in Research Grant from NASA has enabled a team of undergraduates from Valdosta State University, lead by Dr. Martha Leake, to spectroscopically and photometrically search for aqueously altered minor planets. To carry out the necessary preparations, calculations, and measurements, students are using CCD and Spectroscopy equipment provided by VSU, a .4-m telescope in Valdosta, in addition to a .9-m telescope at Kitt Peak, belonging to the SARA consortium (Southeastern Association for Research in Astronomy). Focusing on primitive C-class asteroids, the team is looking for water of hydration, in the form of absorption bands occurring at specific, previously researched wavelengths. The evidence occurring at these wavelengths suggests the extent of alteration in small solar-system bodies. Equipment being utilized includes an ST-6 and Axiom CCD Cameras, and an Optomechanics 10C spectrograph, and several "intermediate-band" filters to target the specified wavelengths essential to detection o f aqueously altered minerals. Test runs on Valdosta's .4-m are currently being conducted to inspect new equipment and develop analogs for more efficient observation runs on SARA's .9-m telescope. Students were originally chosen on a competitive basis, having to submit formal applications. Three were selected for JOVE research: Roy Kilgard, senior astronomy major; Katherine Semmes, junior physics major; and myself, Lisa Watkins, sophomore astronomy major. Roy Kilgard graduated in the Spring of 1997 with his Astronomy degree, and the position was filled by Brent Collier, a junior Geosciences major at VSU. Students' research is monitored and directed by the project mentor and grant recipient, Dr. Martha Leake.

Amino acid compositions in heated carbonaceous chondrites and their compound-specific nitrogen isotopic ratios

NASA Astrophysics Data System (ADS)

Chan, Queenie Hoi Shan; Chikaraishi, Yoshito; Takano, Yoshinori; Ogawa, Nanako O.; Ohkouchi, Naohiko

2016-01-01

A novel method has been developed for compound-specific nitrogen isotope compositions with an achiral column which was previously shown to offer high precision for nitrogen isotopic analysis. We applied the method to determine the amino acid contents and stable nitrogen isotopic compositions of individual amino acids from the thermally metamorphosed (above 500 °C) Antarctic carbonaceous chondrites Ivuna-like (CI)1 (or CI-like) Yamato (Y) 980115 and Ornans-like (CO)3.5 Allan Hills (ALH) A77003 with the use of gas chromatography/combustion/isotope ratio mass spectrometry. ALHA77003 was deprived of amino acids due to its extended thermal alteration history. Amino acids were unambiguously identified in Y-980115, and the δ15N values of selected amino acids (glycine +144.8 ‰; α-alanine +121.2 ‰) are clearly extraterrestrial. Y-980115 has experienced an extended period of aqueous alteration as indicated by the presence of hydrous mineral phases. It has also been exposed to at least one post-hydration short-lived thermal metamorphism. Glycine and alanine were possibly produced shortly after the accretion event of the asteroid parent body during the course of an extensive aqueous alteration event and have abstained from the short-term post-aqueous alteration heating due to the heterogeneity of the parent body composition and porosity. These carbonaceous chondrite samples are good analogs that offer important insights into the target asteroid Ryugu of the Hayabusa-2 mission, which is a C-type asteroid likely composed of heterogeneous materials including hydrated and dehydrated minerals.

Chemical Disequilibria and Sources of Gibbs Free Energy Inside Enceladus

NASA Astrophysics Data System (ADS)

Zolotov, M. Y.

2010-12-01

Non-photosynthetic organisms use chemical disequilibria in the environment to gain metabolic energy from enzyme catalyzed oxidation-reduction (redox) reactions. The presence of carbon dioxide, ammonia, formaldehyde, methanol, methane and other hydrocarbons in the eruptive plume of Enceladus [1] implies diverse redox disequilibria in the interior. In the history of the moon, redox disequilibria could have been activated through melting of a volatile-rich ice and following water-rock-organic interactions. Previous and/or present aqueous processes are consistent with the detection of NaCl and Na2CO3/NaHCO3-bearing grains emitted from Enceladus [2]. A low K/Na ratio in the grains [2] and a low upper limit for N2 in the plume [3] indicate low temperature (possibly < 273 K) of aqueous processes. Although many of the energetically favorable redox reactions are sluggish at low temperature, they could be catalyzed by enzymes if organisms were (are) present. The redox conditions in aqueous systems and amounts of available Gibbs free energy should have been affected by the production, consumption and escape of hydrogen. Aqueous oxidation of minerals (Fe-Ni metal, Fe-Ni phosphides, etc.) accreted on Enceladus should have led to H2 production, which is consistent with H2 detection in the plume [1]. Numerical evaluations based on concentrations of plume gases [1] reveal sufficient energy sources available to support metabolically diverse life at a wide range of activities (a) of dissolved H2 (log aH2 from 0 to -10). Formaldehyde, carbon dioxide [c.f. 4], HCN (if it is present), methanol, acetylene and other hydrocarbons have the potential to react with H2 to form methane. Aqueous hydrogenations of acetylene, HCN and formaldehyde to produce methanol are energetically favorable as well. Both favorable hydrogenation and hydration of HCN lead to formation of ammonia. Condensed organic species could also participate in redox reactions. Methane and ammonia are the final products of these putative redox transformations. Sulfates may have not formed in cold and/or short-term aqueous environments with a limited H2 escape. In contrast to Earth, Mars and Europa, the moon may have no (or very limited [4]) potential for sulfate reduction. Despite nutrient (C, N, P and S) and metal (e.g. Fe, Ni) rich environments and multiple sources of Gibbs free energy during aqueous episode(s), putative life on Enceladus [4] would have adapted to survive in low water activity alkaline brines rich in ammonia, methanol and organic liquids at temperature >150-170 K. The comet-like abundances of major plume gases and apparent redox disequilibria in aquatic systems are consistent with a minimal influence of aqueous processes on endogenic chemical reactions and may indicate abiotic interior. Alternatively, plume gases may represent never melted primordial parcels of the icy shell, while the deeper interior could contain altered species transformed in abiotic and/or biological processes. Refs: [1] Waite J. et al. (2009) Nature 460, 487-490. [2] Postberg F. et al. (2009) Nature 459, 1098-1101. [3] Hansen C. et al. (2010) 38th COSPAR Sci. Assembly. [4] McKay C. et al. (2008) Astrobiology 8, 909-919.

Chemistry and Mineralogy of Antarctica Dry Valley Soils: Implications for Mars

NASA Technical Reports Server (NTRS)

Quinn, J. E.; Golden, D. C.; Graff, T. G.; Ming, D. W.; Morris, R. V.; Douglas, S.; Kounaves, S. P.; McKay, C. P.; Tamppari, L, K.; Smith, P. H.;

Computational investigation of structural and electronic properties of aqueous interfaces of GaN, ZnO, and a GaN/ZnO alloy.

PubMed

Kharche, Neerav; Hybertsen, Mark S; Muckerman, James T

2014-06-28

The GaN/ZnO alloy functions as a visible-light photocatalyst for splitting water into hydrogen and oxygen. As a first step toward understanding the mechanism and energetics of water-splitting reactions, we investigate the microscopic structure of the aqueous interfaces of the GaN/ZnO alloy and compare them with the aqueous interfaces of pure GaN and ZnO. Specifically, we have studied the (101̄0) surface of GaN and ZnO and the (101̄0) and (12̄10) surfaces of the 1 : 1 GaN/ZnO alloy. The calculations are carried out using first-principles density functional theory based molecular dynamics (DFT-MD). The structure of water within a 3 Å distance from the semiconductor surface is significantly altered by the acid/base chemistry of the aqueous interface. Water adsorption on all surfaces is substantially dissociative such that the surface anions (N or O) act as bases accepting protons from dissociated water molecules while the corresponding hydroxide ions bond with surface cations (Ga or Zn). Additionally, the hard-wall interface presented by the semiconductor imparts ripples in the density of water. Beyond a 3 Å distance from the semiconductor surface, water exhibits a bulk-like hydrogen bond network and oxygen-oxygen radial distribution function. Taken together, these characteristics represent the resting (or "dark") state of the catalytic interface. The electronic structure analysis of the aqueous GaN/ZnO interface suggests that the photogenerated holes may get trapped on interface species other than the adsorbed OH(-) ions. This suggests additional dynamical steps in the water oxidation process.

Reproducing early Martian atmospheric carbon dioxide partial pressure by modeling the formation of Mg-Fe-Ca carbonate identified in the Comanche rock outcrops on Mars

NASA Astrophysics Data System (ADS)

Berk, Wolfgang; Fu, Yunjiao; Ilger, Jan-Michael

2012-10-01

The well defined composition of the Comanche rock's carbonate (Magnesite0.62Siderite0.25Calcite0.11Rhodochrosite0.02) and its host rock's composition, dominated by Mg-rich olivine, enable us to reproduce the atmospheric CO2partial pressure that may have triggered the formation of these carbonates. Hydrogeochemical one-dimensional transport modeling reveals that similar aqueous rock alteration conditions (including CO2partial pressure) may have led to the formation of Mg-Fe-Ca carbonate identified in the Comanche rock outcrops (Gusev Crater) and also in the ultramafic rocks exposed in the Nili Fossae region. Hydrogeochemical conditions enabling the formation of Mg-rich solid solution carbonate result from equilibrium species distributions involving (1) ultramafic rocks (ca. 32 wt% olivine; Fo0.72Fa0.28), (2) pure water, and (3) CO2partial pressures of ca. 0.5 to 2.0 bar at water-to-rock ratios of ca. 500 molH2O mol-1rock and ca. 5°C (278 K). Our modeled carbonate composition (Magnesite0.64Siderite0.28Calcite0.08) matches the measured composition of carbonates preserved in the Comanche rocks. Considerably different carbonate compositions are achieved at (1) higher temperature (85°C), (2) water-to-rock ratios considerably higher and lower than 500 mol mol-1 and (3) CO2partial pressures differing from 1.0 bar in the model set up. The Comanche rocks, hosting the carbonate, may have been subjected to long-lasting (>104 to 105 years) aqueous alteration processes triggered by atmospheric CO2partial pressures of ca. 1.0 bar at low temperature. Their outcrop may represent a fragment of the upper layers of an altered olivine-rich rock column, which is characterized by newly formed Mg-Fe-Ca solid solution carbonate, and phyllosilicate-rich alteration assemblages within deeper (unexposed) units.

Giant convecting mud balls of the early solar system

PubMed Central

Bland, Philip A.; Travis, Bryan J.

2017-01-01

Carbonaceous asteroids may have been the precursors to the terrestrial planets, yet despite their importance, numerous attempts to model their early solar system geological history have not converged on a solution. The assumption has been that hydrothermal alteration was occurring in rocky asteroids with material properties similar to meteorites. However, these bodies would have accreted as a high-porosity aggregate of igneous clasts (chondrules) and fine-grained primordial dust, with ice filling much of the pore space. Short-lived radionuclides melted the ice, and aqueous alteration of anhydrous minerals followed. However, at the moment when the ice melted, no geological process had acted to lithify this material. It would have been a mud, rather than a rock. We tested the effect of removing the assumption of lithification. We find that if the body accretes unsorted chondrules, then large-scale mud convection is capable of producing a size-sorted chondrule population (if the body accretes an aerodynamically sorted chondrule population, then no further sorting occurs). Mud convection both moderates internal temperature and reduces variation in temperature throughout the object. As the system is thoroughly mixed, soluble elements are not fractionated, preserving primitive chemistry. Isotopic and redox heterogeneity in secondary phases over short length scales is expected, as individual particles experience a range of temperature and water-rock histories until they are brought together in their final configuration at the end of convection. These results are consistent with observations from aqueously altered meteorites (CI and CM chondrites) and spectra of primitive asteroids. The “mudball” model appears to be a general solution: Bodies spanning a ×1000 mass range show similar behavior. PMID:28740862

In vitro and in vivo studies of an aqueous extract of Matricaria recutita (German chamomile) on the radiolabeling of blood constituents, on the morphology of red blood cells and on the biodistribution of the radiopharmaceutical sodium pertechnetate

PubMed Central

Garcia-Pinto, Angélica B.; Santos-Filho, Sebastião D.; Carvalho, Jorge J.; Pereira, Mário J. S.; Fonseca, Adenilson S.; Bernardo-Filho, Mário

2013-01-01

Background: Natural products might alter the labeling of blood constituents with technetium-99m (99mTc) and these results may be correlated with modifications of the shape of the red blood cells (RBC). The biodistribution of radiopharmaceuticals can be also altered. Objective: This investigation aimed to determine biological effects of an aqueous extract of chamomile (CE). Materials and Methods: To study the effect of the CE on the labeling of blood constituents with 99mTc, in vitro and in vivo assays were performed. The effect of the CE on the morphology of RBC was observed under light microscope. The images were acquired, processed, and the perimeter/area ratio of the RBC determined. To analyze the effect of the CE on biodistribution of the sodium pertechnetate (Na99mTcO4) in Wistar rats, these animals were treated or not with a CE. Na99mTcO4 was injected, the rats were sacrificed, the organs were removed, weighted and percentage of radioactivity/gram calculated. Result: In the in vitro experiment, the radioactivity on blood cells compartment and on insoluble fractions of plasma was diminished. The shape and the perimeter/area ratio of the RBC were altered in in vitro assays. An increase of the percentage of radioactivity of Na99mTcO4 was observed in stomach after in vivo treatment. Conclusion: These results could be due to substances of the CE or by the products of the metabolism of this extract in the animal organism. These findings are examples of drug interaction with a radiopharmaceutical, which could lead to misdiagnosis in clinical practice with unexpected consequences. PMID:24143045

Context of ancient aqueous environments on Mars from in situ geologic mapping at Endeavour Crater

USGS Publications Warehouse

Crumpler, L.S.; Arvidson, R. E.; Bell, J.; Clark, B. C.; Cohen, B. A.; Farrand, W. H.; Gellert, Ralf; Golombek, M.; Grant, J. A.; Guinness, E.; Herkenhoff, Kenneth E.; Johnson, J. R.; Jolliff, B.; Ming, D. W.; Mittlefehldt, D. W.; Parker, T.; Rice, J. W.; Squyres, S. W.; Sullivan, R.; Yen, A. S.

2015-01-01

Using the Mars Exploration Rover Opportunity, we have compiled one of the first field geologic maps on Mars while traversing the Noachian terrain along the rim of the 22 km diameter Endeavour Crater (Latitude −2°16′33″, Longitude −5°10′51″). In situ mapping of the petrographic, elemental, structural, and stratigraphic characteristics of outcrops and rocks distinguishes four mappable bedrock lithologic units. Three of these rock units predate the surrounding Burns formation sulfate-rich sandstones and one, the Matijevic Formation, represents conditions on early Mars predating the formation of Endeavour Crater. The stratigraphy assembled from these observations includes several geologic unconformities. The differences in lithologic units across these unconformities record changes in the character and intensity of the Martian aqueous environment over geologic time. Water circulated through fractures in the oldest rocks over periods long enough that texturally and elementally significant alteration occurred in fracture walls. These oldest pre-Endeavour rocks and their network of mineralized and altered fractures were preserved by burial beneath impact ejecta and were subsequently exhumed and exposed. The alteration along joints in the oldest rocks and the mineralized veins and concentrations of trace metals in overlying lithologic units is direct evidence that copious volumes of mineralized and/or hydrothermal fluids circulated through the early Martian crust. The wide range in intensity of structural and chemical modification from outcrop to outcrop along the crater rim shows that the ejecta of large (>8 km in diameter) impact craters is complex. These results imply that geologic complexity is to be anticipated in other areas of Mars where cratering has been a fundamental process in the local and regional geology and mineralogy.

Emplacement of Widespread Fe/Mg Phyllosilicate Layer in West Margaritifer Terra, Mars

NASA Astrophysics Data System (ADS)

Seelos, K. D.; Maxwell, R. E.; Seelos, F. P.; Buczkowski, D.; Viviano-Beck, C. E.

2017-12-01

West Margaritifer Terra is located at the eastern end of Valles Marineris at the complex intersection of chaos terrains, cratered highlands, and multiple generations of outflow channels. Adjacent regions host layered phyllosilicates thought to indicate early Mars pedogenic and/or ground water-based alteration (e.g., Le Deit et al., 2012), and indeed, hydrologic modeling supports prolonged aqueous activity in the Noachian and Hesperian eras (Andrews-Hanna and Lewis, 2011). The remnant high-standing plateaus in West Margaritifer (0-15°S, 325-345°E) host numerous phyllosilicate-bearing outcrops as well and are the focus of this study. Here, we performed a systematic mapping and characterization of mineralogy and morphology of these deposits in order to assess similarity to other layered phyllosilicates and evaluate potential formation mechanisms. Utilizing multiple remote sensing datasets, we identified three types of phyllosilicate exposures distributed throughout the region: 1) along upper chaos fracture walls, 2) in erosional windows on the plains, and 3) in crater walls and ejecta. Outcrops are spectrally indicative of Fe/Mg smectite (most similar to saponite) and only rare, isolated occurrences of Al-phyllosilicate were observed. Morphologically, the layer is a few to 10 m thick, light-toned, polygonally fractured at decameter scales, and vertical subparallel banding is evident in places. These characteristics were used along with spatial distribution, elevation, and geologic context to evaluate 4 potential formation mechanisms: fluvio-lacustrine, pedogenesis, diagenesis, and hydrothermal alteration. We find that the widespread distribution and spectral homogeneity of the layer favors formation via groundwater alteration and/or pedogenic weathering. This is consistent with interpretations of similar layered phyllosilicates in NW Noachis Terra and the Valles Marineris plains to the west, and significantly extends the area over which these aqueous processes operated in Noachian times.

Genetic aspects of barite mineralization related to rocks of the teschenite association in the Silesian Unit, Outer Western Carpathians, Czech Republic

NASA Astrophysics Data System (ADS)

Jirásek, Jakub; Dolníček, Zdeněk; Matýsek, Dalibor; Urubek, Tomáš

2017-04-01

Barite is a relatively uncommon phase in vein and amygdule mineralizations hosted by igneous rocks of the teschenite association in the Silesian Unit (Western Carpathians). In macroscopically observable sizes, it has been reported from 10 sites situated only in the Czech part of the Silesian Unit. Microscopic barite produced by the hydrothermal alteration of rock matrix and also by the supergene processes is more abundant. We examined four samples of barite by mineralogical and geochemical methods. Electron microprobe analyses proved pure barites with up to 0.038 apfu Sr and without remarkable internal zonation. Fluid inclusion and sulphur isotope data suggests that multiple sources of fluid components have been involved during barite crystallization. Barite contains primary and secondary aqueous all-liquid (L) or less frequent two-phase (L+V) aqueous fluid inclusions with variable salinity (0.4-2.9 wt. % NaCl eq.) and homogenization temperatures between 77 and 152 °C. The higher-salinity fluid endmember was probably Cretaceous seawater and the lower-salinity one was probably diagenetic water derived from surrounding flysch sediments during compaction and thermal alteration of clay minerals. The δ34S values of barite samples range between -1.0 ‰ and +16.4 ‰ CDT suggesting participation of two sources of sulphate, one with a near-zero δ34S values probably derived from wall rocks and another with high δ34S values being most probably sulphate from the Cretaceous seawater. All results underline the role of externally derived fluids during post-magmatic alteration of bodies of rock of the teschenite association.

Interaction among minerals, organics and water in comets: insights from Antarctic micrometeorites

NASA Astrophysics Data System (ADS)

Nagahara, Hiroko; Noguchi, Takaaki; Yabuta, Hikaru; Itoh, Shoichi; Sakamoto, Naoya; Mitsunari, Takuya; Okubo, Aya; Okazaki, Ryuji; Nakamura, Tomoki; Tachibana, Shogo; Terada, Kentaro; Ebihara, Mitsuru; Imae, Naoya; Kimura, Makoto

2016-04-01

The evolution and interaction of inorganic materials and organic materials are one of the crucial issues of space science, which is also a main topic of current planetary missions. In order to clarify the early stage of evo-lution of primitive materials in the solar system, we have carried out a comprehensive study on micrometeorites collected from the Antarctica virgin snow with SEM, TEM, Carbon-, N-, and O-XANES, and SIMS. On the basis of observation, we estimate the primary materials and the sequence of aqueous reaction in the inorganic and organic materials. The most primitive materials are GEMS (amorphous silicate with Fe-metal and sulfide), small olivine and low-Ca pyroxene, and pyrrhotite, which are embedded in organic materials. The or-ganic materials are macromolecules being rich in C=O groups with subordinate amount of C≡N and/or C=N-C groups, and they accompany D and 15N enrichments. Due to the heavy hydrogen and nitrogen isotopic composi-tions, the organics are estimated to be originated at very low temperature in the molecular cloud or a prestellar environment, which also generated various organic molecules. The aqueous alteration reaction started at first in organic materials, where N-heterocycle, δD, and δ15N are lost and the organics become aromatic-rich. GEMS altered next, where metallic Fe dissolved into water to form Fe-rich saponite remaining Mg-rich amorphous silicate (Stage I). The aromaticity of the organics increases, and the chemical nature of organics becomes close to insoluble organic materials in primitive chondrites. Then, sulfide in GEMS, small olivine and low-Ca pyroxene grains, and Fe-rich saponite react with water to form Mg-rich saponite and Fe-hydroxide (Stage II). Sulfur may have been incorporated into phyllosilicate and/or organics or flew away. Finally, heterogeneous phyllosilicates at Stage II were homogenized to be Mg-rich saponite with formation of carbonate and loss of organics (Stage III). Carbon to form carbonate were supplied from organics or carbon dioxide and/or methane ice. Finally, the assemblage of micrometeorites becomes Mg-saponite, magnetite, and carbonates, of which mineral assemblage and chemical compositions are very similar to those of primitive carbonaceous chondrites. Stages I and II should have taken place at ~0 °C and almost instantaneously, probably in hours to days, in order to prevent total aqueous alteration of silicates. Therefore, most plausible process would be transient heat-ing by an impact. On the other hand, Stage III was at a little higher temperature in order to homogenize Mg and Fe in heterogeneous phyllosilicates and/or lasted for a little longer duration. A possible process may be either by a shock or approaching of cometary bodies to the Sun. However, we should evaluate the temperature and dura-tion very carefully, because the Rosetta mission showed us extremely porous nature of comets. It should be noted that the final products of aqueous reactions shown in the present study are the same as those of primitive carbonaceous chondrites. More compact nature of chondrites and probably higher temperature by short-lived radio-isotopes resulted in pervasive water flow in the bodies and through alteration of silicates into phyllosilicates.

Guava extract (Psidium guajava) alters the labelling of blood constituents with technetium-99m.

PubMed

Abreu, P R C; Almeida, M C; Bernardo, R M; Bernardo, L C; Brito, L C; Garcia, E A C; Fonseca, A S; Bernardo-Filho, M

2006-06-01

Psidium guajava (guava) leaf is a phytotherapic used in folk medicine to treat gastrointestinal and respiratory disturbances and is used as anti-inflammatory medicine. In nuclear medicine, blood constituents (BC) are labelled with technetium-99m ((99m)Tc) and used to image procedures. However, data have demonstrated that synthetic or natural drugs could modify the labelling of BC with (99m)Tc. The aim of this work was to evaluate the effects of aqueous extract of guava leaves on the labelling of BC with (99m)Tc. Blood samples of Wistar rats were incubated with different concentrations of guava extract and labelled with (99m)Tc after the percentage of incorporated radioactivity (%ATI) in BC was determined. The results suggest that aqueous guava extract could present antioxidant action and/or alters the membrane structures involved in ion transport into cells, thus decreasing the radiolabelling of BC with (99m)Tc. The data showed significant (P<0.05) alteration of ATI in BC from blood incubated with guava extract.

A framework for expanding aqueous chemistry in the ...

EPA Pesticide Factsheets

This paper describes the development and implementation of an extendable aqueous-phase chemistry option (AQCHEM − KMT(I)) for the Community Multiscale Air Quality (CMAQ) modeling system, version 5.1. Here, the Kinetic PreProcessor (KPP), version 2.2.3, is used to generate a Rosenbrock solver (Rodas3) to integrate the stiff system of ordinary differential equations (ODEs) that describe the mass transfer, chemical kinetics, and scavenging processes of CMAQ clouds. CMAQ's standard cloud chemistry module (AQCHEM) is structurally limited to the treatment of a simple chemical mechanism. This work advances our ability to test and implement more sophisticated aqueous chemical mechanisms in CMAQ and further investigate the impacts of microphysical parameters on cloud chemistry. Box model cloud chemistry simulations were performed to choose efficient solver and tolerance settings, evaluate the implementation of the KPP solver, and assess the direct impacts of alternative solver and kinetic mass transfer on predicted concentrations for a range of scenarios. Month-long CMAQ simulations for winter and summer periods over the US reveal the changes in model predictions due to these cloud module updates within the full chemical transport model. While monthly average CMAQ predictions are not drastically altered between AQCHEM and AQCHEM − KMT, hourly concentration differences can be significant. With added in-cloud secondary organic aerosol (SOA) formation from bio

Effect of extract of Hibiscus on the ultrastructure of the testis in adult mice.

PubMed

Mahmoud, Yomna Ibrahim

2012-07-01

Hibiscus sabdariffa extract is a popular beverage in many tropical and sub-tropical countries. Although, Hibiscus tea is known for its medicinal effects for thousands of years, scientific evidence of its systemic safety is very limited. The current study aimed to assess the potential adverse effects of H. sabdariffa extract on sperm morphology and testicular ultrastructure of albino mice. Thirty adult male albino mice were divided into three equal groups and were given: (a) distilled water, (b) cold Hibiscus aqueous extract, and (c) boiled Hibiscus aqueous extract. Hibiscus extract was administered orally daily for 4 weeks in a dose of 200 mg/kg body weight/mouse. Twenty-four hours after the last treatment, mice were decapitated and the testes and epididymides were excised and processed for transmission electron microscopy to assess ultrastructural and sperm abnormalities. The results clearly demonstrate that aqueous extracts from dried calyx of H. sabdariffa, either cold or boiled, alter normal sperm morphology and testicular ultrastructure and adversely influence the male reproductive fertility in albino mice. The current data suggest that Hibiscus extract should be consumed with caution, and reasonable estimates of the human risk associated with its consumption should be provided. Copyright © 2011 Elsevier GmbH. All rights reserved.

Chondritic Meteorites: Nebular and Parent-Body Formation Process

NASA Technical Reports Server (NTRS)

Rubin, Alan E.

1997-01-01

Chondritic meteorites are the products of condensation, agglomeration and accretion of material in the solar nebula; these objects are the best sources of information regarding processes occurring during the early history of the solar system. We obtain large amounts of high-quality chemical and petrographic data and use them to infer chemical fractionation processes that occurred in the solar nebula and on meteorite parent bodies during thermal metamorphism, shock metamorphism and aqueous alteration. We compare diverse groups of chondrites and model their different properties in terms of processes that differed at different nebular locations or on different parent-bodies. In order to expand our set of geochemically important elements (particularly Si, C, P and S) and to distinguish the different oxidation states of Fe, Greg Kallemeyn spent three months (1 Sept. - 30 Nov. 1995) at the Smithsonian Institution to learn Eugene Jarosewich's wet chemical techniques. Key specimens from the recently established CK, CR and R chondrite groups were analyzed.

ASRM process development in aqueous cleaning

NASA Technical Reports Server (NTRS)

Swisher, Bill

1992-01-01

Viewgraphs are included on process development in aqueous cleaning which is taking place at the Aerojet Advanced Solid Rocket Motor (ASRM) Division under a NASA Marshall Space and Flight Center contract for design, development, test, and evaluation of the ASRM including new production facilities. The ASRM will utilize aqueous cleaning in several manufacturing process steps to clean case segments, nozzle metal components, and igniter closures. ASRM manufacturing process development is underway, including agent selection, agent characterization, subscale process optimization, bonding verification, and scale-up validation. Process parameters are currently being tested for optimization utilizing a Taguci Matrix, including agent concentration, cleaning solution temperature, agitation and immersion time, rinse water amount and temperature, and use/non-use of drying air. Based on results of process development testing to date, several observations are offered: aqueous cleaning appears effective for steels and SermeTel-coated metals in ASRM processing; aqueous cleaning agents may stain and/or attack bare aluminum metals to various extents; aqueous cleaning appears unsuitable for thermal sprayed aluminum-coated steel; aqueous cleaning appears to adequately remove a wide range of contaminants from flat metal surfaces, but supplementary assistance may be needed to remove clumps of tenacious contaminants embedded in holes, etc.; and hot rinse water appears to be beneficial to aid in drying of bare steel and retarding oxidation rate.

Natural fumarolic alteration of fluorapatite, olivine, and basaltic glass, and implications for habitable environments on Mars.

PubMed

Hausrath, Elisabeth M; Tschauner, Oliver

2013-11-01

Fumaroles represent a very important potential habitat on Mars because they contain water and nutrients. Global deposition of volcanic sulfate aerosols may also have been an important soil-forming process affecting large areas of Mars. Here we identify alteration from the Senator fumarole, northwest Nevada, USA, and in low-temperature environments near the fumarole to help interpret fumarolic and acid vapor alteration of rocks and soils on Mars. We analyzed soil samples and fluorapatite, olivine, and basaltic glass placed at and near the fumarole in in situ mineral alteration experiments designed to measure weathering under natural field conditions. Using synchrotron X-ray diffraction, we clearly observe hydroxyl-carbonate-bearing fluorapatite as a fumarolic alteration product of the original material, fluorapatite. The composition of apatites as well as secondary phosphates has been previously used to infer magmatic conditions as well as fumarolic conditions on Mars. To our knowledge, the observations reported here represent the first documented instance of formation of hydroxyl-carbonate-bearing apatite from fluorapatite in a field experiment. Retreat of olivine surfaces, as well as abundant NH4-containing minerals, was also characteristic of fumarolic alteration. In contrast, alteration in the nearby low-temperature environment resulted in formation of large pits on olivine surfaces, which were clearly distinguishable from the fumarolic alteration. Raman signatures of some fumarolically impacted surfaces are consistent with detection of the biological molecules chlorophyll and scytenomin, potentially useful biosignatures. Observations of altered minerals on Mars may therefore help identify the environment of formation and understand the aqueous history and potential habitability of that planet.

SITE TECHNOLOGY CAPSULE: PINTAIL SYSTEMS INC'S AQUEOUS BIOCYANIDE PROCESS

EPA Science Inventory

A field treatability study of an innovative biological treatment technology for cyanide destruction and metals immobilizaton from an aqueous mine process stream was held at the Echo Bay/McCoy Cove mine site in Nevada. The Aqueous Biocyanide Process, developed and operated by Pint...

New Constraints on the Deposition and Alteration History of Mt. Sharp in Gale Crater, Mars

NASA Astrophysics Data System (ADS)

Rice, M. S.; Horgan, B. H. N.; Fraeman, A.; Ackiss, S. E.

2015-12-01

The Mars Science Laboratory (MSL) rover is currently investigating the lower stratigraphy of northwestern Mt. Sharp, the 5 km thick stack of layered rock that makes up the central mound of Gale Crater. Previous near-infrared spectral investigations from orbit using CRISM have shown that this portion of the mound exhibits a diverse mineralogy that may indicate changing aqueous environments on early Mars. The relationship of these mineralogic units to stratigraphic units across the full extent of Mt. Sharp is not well understood, although such relationships are key to interpreting the depositional and digenetic history. Here we present new mineral maps derived from CRISM data, as well as detailed stratigraphic columns from around the mound, and we use these new results to constrain hypotheses for the modes of aqueous alteration. Our new CRISM mineral maps are projected and co-registered to HiRISE imagery and DEMs, and include Fe/Mg-smectites, poly- and mono-hydrated sulfates, iron oxides, high-Ca pyroxene, and a ferrous phase with a strong red spectral slope between 1.1-1.8 μm, which is consistent with ferrous alteration phases like ferrous clays. This latter unit consistently overlies Fe/Mg-smectites in NW and SW Mt. Sharp, and is located in topographic benches that are either immediately stratigaphically above hematite-bearing ridges. The presence of ferrous alteration phases supports previous interpretations that hematite formed when an Fe2+-bearing fluid encountered an oxidizing environment. In this scenario, the reducing fluids were created by long-term oxygen limited alteration of Fe-bearing minerals in the near-surface. Downward movement of these fluids may have been limited by the underlying clay layer, forcing lateral flow. On emergence at the surface, the iron was oxidized by photochemical or other redox reactions. On Earth, similar pedogenic processes form hematite ironpans on slopes surrounding poorly-drained hilltops, as well as ancient banded iron formations in shallow coastal waters. The reducing environment inferred from the ferrous phases could be a site of high organic preservation potential, and the redox gradient inferred from the ferric/ferrous mineral relationship could have served as an energy source for chemolithotrophic microbes.

Veneers, rinds, and fracture fills: Relatively late alteration of sedimentary rocks at Meridiani Planum, Mars

USGS Publications Warehouse

Knoll, A.H.; Jolliff, B.L.; Farrand, W. H.; Bell, J.F.; Clark, B. C.; Gellert, Ralf; Golombek, M.P.; Grotzinger, J.P.; Herkenhoff, K. E.; Johson, J.R.; McLennam, S.M.; Morris, Robert; Squyres, S. W.; Sullivan, R.; Tosca, N.J.; Yen, A.; Learner, Z.

2008-01-01

Veneers and thicker rinds that coat outcrop surfaces and partially cemented fracture fills formed perpendicular to bedding document relatively late stage alteration of ancient sedimentary rocks at Meridiani Planum, Mars. The chemistry of submillimeter thick, buff-colored veneers reflects multiple processes at work since the establishment of the current plains surface. Veneer composition is dominated by the mixing of silicate-rich dust and sulfate-rich outcrop surface, but it has also been influenced by mineral precipitation, including NaCl, and possibly by limited physical or chemical weathering of sulfate minerals. Competing processes of chemical alteration (perhaps mediated by thin films of water or water vapor beneath blanketing soils) and sandblasting of exposed outcrop surfaces determine the current distribution of veneers. Dark-toned rinds several millimeters thick reflect more extensive surface alteration but also indicate combined dust admixture, halite precipitation, and possible minor sulfate removal. Cemented fracture fills that are differentially resistant to erosion occur along the margins of linear fracture systems possibly related to impact. These appear to reflect limited groundwater activity along the margins of fractures, cementing mechanically introduced fill derived principally from outcrop rocks. The limited thickness and spatial distribution of these three features suggest that aqueous activity has been rare and transient or has operated at exceedingly low rates during the protracted interval since outcropping Meridiani strata were exposed on the plains surface. Copyright 2008 by the American Geophysical Union.

Osmosis and solute-solvent drag: fluid transport and fluid exchange in animals and plants.

PubMed

Hammel, H T; Schlegel, Whitney M

2005-01-01

In 1903, George Hulett explained how solute alters water in an aqueous solution to lower the vapor pressure of its water. Hulett also explained how the same altered water causes osmosis and osmotic pressure when the solution is separated from liquid water by a membrane permeable to the water only. Hulett recognized that the solute molecules diffuse toward all boundaries of the solution containing the solute. Solute diffusion is stopped at all boundaries, at an open-unopposed surface of the solution, at a semipermeable membrane, at a container wall, or at the boundary of a solid or gaseous inclusion surrounded by solution but not dissolved in it. At each boundary of the solution, the solute molecules are reflected, they change momentum, and the change of momentum of all reflected molecules is a pressure, a solute pressure (i.e., a force on a unit area of reflecting boundary). When a boundary of the solution is open and unopposed, the solute pressure alters the internal tension in the force bonding the water in its liquid phase, namely, the hydrogen bond. All altered properties of the water in the solution are explained by the altered internal tension of the water in the solution. We acclaim Hulett's explanation of osmosis, osmotic pressure, and lowering of the vapor pressure of water in an aqueous solution. His explanation is self-evident. It is the necessary, sufficient, and inescapable explanation of all altered properties of the water in the solution relative to the same property of pure liquid water at the same externally applied pressure and the same temperature. We extend Hulett's explanation of osmosis to include the osmotic effects of solute diffusing through solvent and dragging on the solvent through which it diffuses. Therein lies the explanations of (1) the extravasation from and return of interstitial fluid to capillaries, (2) the return of luminal fluid in the proximal and distal convoluted tubules of a kidney nephron to their peritubular capillaries, (3) the return of interstitial fluid to the vasa recta, (4) return of aqueous humor to the episcleral veins, and (5) flow of phloem from source to sink in higher plants and many more examples of fluid transport and fluid exchange in animal and plant physiology. When a membrane is permeable to water only and when it separates differing aqueous solutions, the flow of water is from the solution with the lower osmotic pressure to the solution with the higher osmotic pressure.

Orbital identification of carbonate-bearing rocks on Mars

USGS Publications Warehouse

Ehlmann, B.L.; Mustard, J.F.; Murchie, S.L.; Poulet, F.; Bishop, J.L.; Brown, A.J.; Calvin, W.M.; Clark, R.N.; Des Marais, D.J.; Milliken, R.E.; Roach, L.H.; Roush, T.L.; Swayze, G.A.; Wray, J.J.

2008-01-01

Geochemical models for Mars predict carbonate formation during aqueous alteration. Carbonate-bearing rocks had not previously been detected on Mars' surface, but Mars Reconnaissance Orbiter mapping reveals a regional rock layer with near-infrared spectral characteristics that are consistent with the presence of magnesium carbonate in the Nili Fossae region. The carbonate is closely associated with both phyllosilicate-bearing and olivine-rich rock units and probably formed during the Noachian or early Hesperian era from the alteration of olivine by either hydrothermal fluids or near-surface water. The presence of carbonate as well as accompanying clays suggests that waters were neutral to alkaline at the time of its formation and that acidic weathering, proposed to be characteristic of Hesperian Mars, did not destroy these carbonates and thus did not dominate all aqueous environments.

Response surface methodology based extraction of Tribulus terrestris leads to an upsurge of antilithiatic potential by inhibition of calcium oxalate crystallization processes.

PubMed

Kaushik, Jyoti; Tandon, Simran; Gupta, Varun; Nayyar, Jasamrit; Singla, Surinder Kumar; Tandon, Chanderdeep

2017-01-01

Tribulus terrestris has significant antilithiatic efficacy established via both in vitro as well as in vivo studies and is used in numerous anti-urolithiatic herbal formulations viz. Cystone, Uriflow, Uritone and Neeri. However, to fully utilize its antilithiatic potential, the influence of different extraction parameters on antilithiatic ability of T. terrestris aqueous extract needs elucidation. Thus, the current study was undertaken using statistically optimized extraction conditions for aqueous extract preparation. Response surface methodology was employed to observe the influence of three variables i.e. temperature (°C), time (h) and solid: liquid ratio (S: L) on the extraction yield (%) and protein content (mg/g) of T. terrestris aqueous extract. RSM results revealed that the high S:L ratio, low temperature and reduced incubation time were optimal conditions for aqueous extraction. Under such extraction conditions the protein content reached the value of 26.6±1.22 mg/g and the obtained extraction yield was 27.32±1.62%. The assessment of antilithiatic activity of 4 selected extracts (AE1-4), revealed enhanced nucleation and aggregation inhibition of calcium oxalate crystals with AE1 and AE2, which in addition significantly altered the size and morphology of calcium oxalate monohydrate (COM) crystals compared to AE3 and AE4. In vitro cell culture based studies on renal epithelial cells (MDCK, NRK-52E and PK 15) proved that the AE1 showed higher cytoprotective potency by increasing cell viability as compared to the oxalate treated group. The free radical scavenging activity of aqueous extract lowered the reactive oxygen specie's induced damage and potentially reduced the signals of programmed cell death due to oxalate injury. In addition, modulation of the COM crystal morphology was enhanced by AE1 as compared to AE2. The FTIR and GC-MS analysis of AE1, showed the presence of biomolecules which could aid in the attenuation of lithiatic process. In the light of these results the utility of the RSM approach to fully optimize the antilithiatic potential of T. terrestris cannot be undermined.

Immediate impact on the rim zone of cement based materials due to chemical attack

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

Schwotzer, M., E-mail: matthias.schwotzer@kit.edu; Scherer, T.; Gerdes, A.

2015-01-15

Cement based materials are in their widespread application fields exposed to various aqueous environments. This can lead to serious chemical changes affecting the durability of the materials. In particular in the context of service life prediction a detailed knowledge of the reaction mechanisms is a necessary base for the evaluation of the aggressivity of an aqueous medium and this is deduced commonly from long term investigations. However, these processes start immediately at the material/water-interface, when a cementitious system comes into contact with an aqueous solution, altering here the chemical composition and microstructure. This rim zone represents the first hurdle thatmore » has to be overcome by an attacking aqueous solution. Therefore, the properties of the surface near area should be closely associated with the further course of deterioration processes by reactive transport. In this context short term exposure experiments with hardened cement paste over 4 and 48 h have been carried out with demineralized water, hard tap water and different sulfate solutions. In order to investigate immediate changes in the near-surface region, depth profile cuts have been performed on the cement paste samples by means of focused ion beam preparation techniques. A scanning beam of Gallium ions is applied to cut a sharp edge in the cement paste surface, providing insights into the composition and microstructure of the upper ten to hundred microns. Electron microscopic investigations on such a section of the rim zone, together with surface sensitive X-ray diffraction accompanied by a detailed characterization of the bulk composition confirm that the properties of the material/water interface are of relevance for the durability of cement based systems in contact with aqueous solutions. In this manner, focused ion beam investigations constitute auspicious tools to contribute to a more sophisticated understanding of the reaction mechanisms. - Highlights: • The chemical stability is related to the properties of material/water interface. • Properties of the rim zone readjust quickly, triggered by hydrochemical conditions. • Durability research can be improved by combining FIB techniques and common analytics.« less

Response surface methodology based extraction of Tribulus terrestris leads to an upsurge of antilithiatic potential by inhibition of calcium oxalate crystallization processes

PubMed Central

Kaushik, Jyoti; Tandon, Simran; Gupta, Varun; Nayyar, Jasamrit; Singla, Surinder Kumar; Tandon, Chanderdeep

2017-01-01

Tribulus terrestris has significant antilithiatic efficacy established via both in vitro as well as in vivo studies and is used in numerous anti-urolithiatic herbal formulations viz. Cystone, Uriflow, Uritone and Neeri. However, to fully utilize its antilithiatic potential, the influence of different extraction parameters on antilithiatic ability of T. terrestris aqueous extract needs elucidation. Thus, the current study was undertaken using statistically optimized extraction conditions for aqueous extract preparation. Response surface methodology was employed to observe the influence of three variables i.e. temperature (°C), time (h) and solid: liquid ratio (S: L) on the extraction yield (%) and protein content (mg/g) of T. terrestris aqueous extract. RSM results revealed that the high S:L ratio, low temperature and reduced incubation time were optimal conditions for aqueous extraction. Under such extraction conditions the protein content reached the value of 26.6±1.22 mg/g and the obtained extraction yield was 27.32±1.62%. The assessment of antilithiatic activity of 4 selected extracts (AE1-4), revealed enhanced nucleation and aggregation inhibition of calcium oxalate crystals with AE1 and AE2, which in addition significantly altered the size and morphology of calcium oxalate monohydrate (COM) crystals compared to AE3 and AE4. In vitro cell culture based studies on renal epithelial cells (MDCK, NRK-52E and PK 15) proved that the AE1 showed higher cytoprotective potency by increasing cell viability as compared to the oxalate treated group. The free radical scavenging activity of aqueous extract lowered the reactive oxygen specie’s induced damage and potentially reduced the signals of programmed cell death due to oxalate injury. In addition, modulation of the COM crystal morphology was enhanced by AE1 as compared to AE2. The FTIR and GC-MS analysis of AE1, showed the presence of biomolecules which could aid in the attenuation of lithiatic process. In the light of these results the utility of the RSM approach to fully optimize the antilithiatic potential of T. terrestris cannot be undermined. PMID:28846699

Insights into the Martian Regolith from Martian Meteorite Northwest Africa 7034

NASA Technical Reports Server (NTRS)

McCubbin, Francis M.; Boyce, Jeremy W.; Szabo, Timea; Santos, Alison R.; Domokos, Gabor; Vazquez, Jorge; Moser, Desmond E.; Jerolmack, Douglas J.; Keller, Lindsay P.; Tartese, Romain

2015-01-01

Everything we know about sedimentary processes on Mars is gleaned from remote sensing observations. Here we report insights from meteorite Northwest Africa (NWA) 7034, which is a water-rich martian regolith breccia that hosts both igneous and sedimentary clasts. The sedimentary clasts in NWA 7034 are poorly-sorted clastic siltstones that we refer to as protobreccia clasts. These protobreccia clasts record aqueous alteration process that occurred prior to breccia formation. The aqueous alteration appears to have occurred at relatively low Eh, high pH conditions based on the co-precipitation of pyrite and magnetite, and the concomitant loss of SiO2 from the system. To determine the origin of the NWA 7034 breccia, we examined the textures and grain-shape characteristics of NWA 7034 clasts. The shapes of the clasts are consistent with rock fragmentation in the absence of transport. Coupled with the clast size distribution, we interpret the protolith of NWA 7034 to have been deposited by atmospheric rainout resulting from pyroclastic eruptions and/or asteroid impacts. Cross-cutting and inclusion relationships and U-Pb data from zircon, baddelleyite, and apatite indicate NWA 7034 lithification occurred at 1.4-1.5 Ga, during a short-lived hydrothermal event at 600-700 C that was texturally imprinted upon the submicron groundmass. The hydrothermal event caused Pb-loss from apatite and U-rich metamict zircons, and it caused partial transformation of pyrite to submicron mixtures of magnetite and maghemite, indicating the fluid had higher Eh than the fluid that caused pyrite-magnetite precipitation in the protobreccia clasts. NWA 7034 also hosts ancient 4.4 Ga crustal materials in the form of baddelleyites and zircons, providing up to a 2.9 Ga record of martian geologic history. This work demonstrates the incredible value of sedimentary basins as scientific targets for Mars sample return missions, but it also highlights the importance of targeting samples that have not been overprinted by metamorphic processes, which is the case for NWA 7034.

Metal separations using aqueous biphasic partitioning systems

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

Chaiko, D.J.; Zaslavsky, B.; Rollins, A.N.

1996-05-01

Aqueous biphasic extraction (ABE) processes offer the potential for low-cost, highly selective separations. This countercurrent extraction technique involves selective partitioning of either dissolved solutes or ultrafine particulates between two immiscible aqueous phases. The extraction systems that the authors have studied are generated by combining an aqueous salt solution with an aqueous polymer solution. They have examined a wide range of applications for ABE, including the treatment of solid and liquid nuclear wastes, decontamination of soils, and processing of mineral ores. They have also conducted fundamental studies of solution microstructure using small angle neutron scattering (SANS). In this report they reviewmore » the physicochemical fundamentals of aqueous biphase formation and discuss the development and scaleup of ABE processes for environmental remediation.« less

Ceramic electrolyte coating methods

DOEpatents

Seabaugh, Matthew M.; Swartz, Scott L.; Dawson, William J.; McCormick, Buddy E.

2004-10-12

Processes for preparing aqueous suspensions of a nanoscale ceramic electrolyte material such as yttrium-stabilized zirconia. The invention also includes a process for preparing an aqueous coating slurry of a nanoscale ceramic electrolyte material. The invention further includes a process for depositing an aqueous spray coating slurry including a ceramic electrolyte material on pre-sintered, partially sintered, and unsintered ceramic substrates and products made by this process.

Possible Bacteria in Nakhla

NASA Technical Reports Server (NTRS)

McKay, David S., Jr.; Westall, F.; Wentworth, S. W.; Thomas-Keptra, K.

1999-01-01

Mars Agueous Alteration Nakhla contains alteration products in an extensive network of which fill cracks, veins, and void spaces, composed of smectite, although in some cases they are amorphous and gel-like. Strong evidence presented show that these alteration products developed on Mars: some veins are offset by impact faulting of olivine followed by annealing of the olivine, and veins near the fusion crust show partial vesicle development suggesting heating and volatile liberation. The smectite-containing cracks and veins are interpreted as low temperature aqueous alteration on Mars. We have been studying these veins with optical microscopy and high resolution SEM.

Hematite Spherules in Basaltic Tephra Altered Under Aqueous, Acid-Sulfate Conditions on Mauna Kea Volcano, Hawaii: Possible Clues for the Occurrence of Hematite-Rich Spherules in the Burns Formation at Meridiani Planum, Mars

NASA Technical Reports Server (NTRS)

Morris, R. V.; Ming, D. W.; Graff, T. G.; Arvidson, R. E.; Bell, J. F., III; Squyres, S. W.; Mertzman, S. A.; Gruener, J. E.; Golden, D. C.; Robinson, G. A.

2005-01-01

Iron-rich spherules (>90% Fe2O3 from electron microprobe analyses) approx.10-100 microns in diameter are found within sulfate-rich rocks formed by aqueous, acid-sulfate alteration of basaltic tephra on Mauna Kea volcano, Hawaii. Although some spherules are nearly pure Fe, most have two concentric compositional zones, with the core having a higher Fe/Al ratio than the rim. Oxide totals less than 100% (93-99%) suggest structural H2O and/or /OH. The transmission Moessbauer spectrum of a spherule-rich separate is dominated by a hematite (alpha-Fe2O3) sextet whose peaks are skewed toward zero velocity. Skewing is consistent with Al(3+) for Fe(3+) substitution and structural H2O and/or /OH. The grey color of the spherules implies specular hematite. Whole-rock powder X-ray diffraction spectra are dominated by peaks from smectite and the hydroxy sulfate mineral natroalunite as alteration products and plagioclase feldspar that was present in the precursor basaltic tephra. Whether spherule formation proceeded directly from basaltic material in one event (dissolution of basaltic material and precipitation of hematite spherules) or whether spherule formation required more than one event (formation of Fe-bearing sulfate rock and subsequent hydrolysis to hematite) is not currently constrained. By analogy, a formation pathway for the hematite spherules in sulfate-rich outcrops at Meridiani Planum on Mars (the Burns formation) is aqueous alteration of basaltic precursor material under acid-sulfate conditions. Although hydrothermal conditions are present on Mauna Kea, such conditions may not be required for spherule formation on Mars if the time interval for hydrolysis at lower temperatures is sufficiently long.

Enzyme kinetics in acoustically levitated droplets of supercooled water: a novel approach to cryoenzymology.

PubMed

Weis, David D; Nardozzi, Jonathan D

2005-04-15

The rate of the alkaline phosphatase-catalyzed hydrolysis of 4-methylumbelliferone phosphate was measured in acoustically levitated droplets of aqueous tris (50 mM) at pH 8.5 at 22 +/- 2 degrees C and in supercooled solution at -6 +/- 2 degrees C. At 22 degrees C, the rate of product formation was in excellent agreement with the rate observed in bulk solution in a cuvette, indicating that the acoustic levitation process does not alter the enzyme activity. The rate of the reaction decreased 6-fold in supercooled solution at -6 +/- 2 degrees C. The acoustic levitator apparatus is described in detail.

Metal-Catalyzed Aqueous Oxidation Processes in Merged Microdroplets

NASA Astrophysics Data System (ADS)

Davis, R. D.; Wilson, K. R.

2017-12-01

Iron-catalyzed production of reactive oxygen species (ROS) from hydrogen peroxide (Fenton's reaction) is a fundamental process throughout nature, from groundwater to cloud droplets. In recent years, Fenton's chemistry has gained further interest in atmospheric science as a potentially important process in the oxidation of aqueous secondary organic aerosol (e.g., Chu et al., Sci. Rep., 2017), with some observations indicating that Fenton's reaction proceeds at a higher rate at aerosol interfaces compared to in the bulk (Enami et al., PNAS, 2014). However, a fundamental-level mechanistic understanding of this process remains elusive and the relative importance of interfacial versus bulk chemistry for aqueous organic processing via Fenton's has yet to be fully established. Here, we present a microreactor experimental approach to studying aqueous-phase Fenton's chemistry in microdroplets by rapidly mixing droplets of different composition. Utilizing two on-demand droplet generators, a stream of microdroplets containing aqueous iron chloride were merged with a separate stream of microdroplets containing aqueous hydrogen peroxide and a range of aromatic organic compounds, initiating ROS production and subsequent aqueous-phase oxidation reactions. Upon merging, mixing of the microdroplets occurred in submillisecond timescales, thus allowing the reaction progress to be monitored with high spatial and temporal resolution. For relatively large microreactor (droplet) sizes (50 µm diameter post-merging), the Fenton-initiated aqueous oxidation of aromatic organic compounds in merged microdroplets was consistent with bulk predictions with hydroxyl radicals as the ROS. The microdroplet-size dependence of this observation, along with the role of other ROS species produced from Fenton and Fenton-like processes, will be discussed in the context of relative importance to aqueous organic processing of atmospheric particles.

Study on the interaction of graphene oxide‑silver nanocomposites with bovine serum albumin and the formation of nanoparticle-protein corona.

PubMed

Xu, Xiangyu; Mao, Xuyan; Wang, Yunfei; Li, Dandan; Du, Zhongyu; Wu, Weihua; Jiang, Liang; Yang, Jie; Li, Jianjun

2018-05-09

The interaction between graphene oxide-sliver nanocomposites (GO-AgNCPs) and bovine serum albumin (BSA) in aqueous buffer solution was investigated by using several spectroscopic and imaging techniques. The visible absorbance intensity of GO-AgNCPs increased with increasing concentrations of BSA, and a slight redshift of the surface plasmon resonance band (SPR) occurred due to the absorption of BSA on the surface of GO-AgNCPs. Fluorescence data revealed a static quenching process of BSA caused by GO-AgNCPs. Thermodynamic parameters of the absorption process, including adsorption equilibrium constants, changes in Gibbs free energy (ΔG), enthalpy (ΔH) and entropy (ΔS), were evaluated at different temperatures. Negative values of ΔG showed that this process was spontaneous and the BSA-GO-AgNCPs complex might form in aqueous solution. Negative values of ΔH and ΔS suggested that the binding was mainly an enthalpy-driven process, and van der Waals forces and hydrogen bonding were the major force in the formation of the nanoparticle-protein corona. Analysis of synchronous, three dimensional (3D) fluorescence and circular dichroism (CD) spectra demonstrated that the conformation of BSA was slightly altered in the presence of GO-AgNCPs. The protein corona formed on the surface of GO-AgNCPs was directly observed by scanning probe microscopy (SPM). Copyright © 2018 Elsevier B.V. All rights reserved.

The Origin of Carbon-Bearing Volatiles in a Continental Hydrothermal System in the Great Basin: Water Chemistry and Isotope Characterizations

NASA Technical Reports Server (NTRS)

Fu, Qi; Socki, Richard A.; Niles, Paul B.; Romanek, Christopher; Datta, Saugata; Darnell, Mike

2012-01-01

Hydrothermal systems on Earth are active centers in the crust where organic molecules can be synthesized biotically or abiotically under a wide range of physical and chemical conditions [1-3]. Not only are volatile species (CO, CO2, H2, and hydrocarbons) a reflection of deep-seated hydrothermal alteration processes, but they also form an important component of biological systems. Studying carbon-bearing fluids from hydrothermal systems is of specific importance to understanding (bio-)geochemical processes within these systems. With recent detection of methane in the martian atmosphere [4-7] and the possibility of its hydrothermal origin [8, 9], understanding the formation mechanisms of methane may provide constraints on the history of the martian aqueous environments and climate.

Therapeutic effect of aqueous extracts of three dietary spices and their mixture on lipid metabolism and oxidative stress in a rat model of chronic alcohol consumption.

PubMed

Otunola, Gloria Aderonke; Afolayan, Anthony Jide

2016-07-01

The protective effect of aqueous extracts of three dietary spices, garlic, (Allium sativum), ginger (Zingiber officinale) and pepper (Capsicum frutescens) singly and combined was investigated using a rat model of chronic alcohol intake. Rats were given 30% ethanol, with or without aqueous extracts of garlic, ginger, pepper or mixture of the three administered at 200mg/kg body weight by oral gavage for 28 days. Lipid profile, lipid peroxidation, oxidative and antioxidative profiles of serum, faecal, liver, kidney, heart and brain tissues of the rats were analyzed. Alcohol treatment significantly elevated liver enzymes, lipid peroxidation, depleted antioxidant system and induced histopathological changes in the liver. These alterations were markedly ameliorated by treatment with aqueous extracts of the three spices singly or mixed at 200mg/kg body weight. These results suggest that aqueous extracts of garlic, ginger, pepper or a blend of the three protects against alcohol- induced hypercholesterolemia, lipid peroxidation, oxidative stress and liver damage.

Aqueous process for recovering sulfur from hydrogen sulfide-bearing gas

DOEpatents

Basu, Arunabha

2015-05-05

A process for recovering sulfur from a hydrogen sulfide-bearing gas utilizes an aqueous reaction medium, a temperature of about 110-150.degree. C., and a high enough pressure to maintain the aqueous reaction medium in a liquid state. The process reduces material and equipment costs and addresses the environmental disadvantages associated with known processes that rely on high boiling point organic solvents.

SOLVENT EXTRACTION PROCESS FOR SEPARATING ACTINIDE AND LANTHANIDE METAL VALUES

DOEpatents

Hildebrandt, R.A.; Hyman, H.H.; Vogler, S.

1962-08-14

A process of countercurrently extracting an aqueous mineral acid feed solution for the separation of actinides from lanthanides dissolved therern is described. The feed solution is made acid-defrcient with alkali metal hydroxide prior to.contact with acid extractant; during extraction, however, acid is transferred from organic to aqueous solution and the aqueous solution gradually becomes acid. The acid-deficient phase ' of the process promotes the extraction of the actinides, while the latter acid phase'' of the process improves retention of the lanthanides in the aqueous solution. This provides for an improved separation. (AEC)

Non-nebular Origin of Dark Mantles Around Chondrules and Inclusions in CM Chondrites

NASA Technical Reports Server (NTRS)

Trigo-Rodriquez, Josep M.; Rubin, Alan E.; Wasson, John T.

2006-01-01

Our examination of nine CM chondrites that span the aqueous alteration sequence leads us to conclude that compact dark fine mantles surrounding chondrules and inclusions in CM chondrites are not discrete fine-grained rims acquired in the solar nebula as modeled by Metzler et al. [Accretionary dust mantles in CM chondrites: evidence for solar nebula processes. Geochim. Cosmochim. Acta 56, 1992, 2873-28971. Nebular processes that lead to agglomeration produce materials with porosities far higher than those in the dark mantles. We infer that the mantles were produced from porous nebular materials on the CM parent asteroid by impact-compaction (a process that produces the lowest porosity adjacent to chondrules and inclusions). Compaction was followed by aqueous alteration that formed tochilinite, serpentine, Ni-bearing sulfide, and other secondary products in voids in the interchondrule regions. Metzler et al. reported a correlation between mantle thickness and the radius of the enclosed object. In Yamato 791 198 we find no correlation when all sizes of central objects and dark lumps are included but a significant correlation (r(sup 2) = 0.44) if we limit consideration to central objects with radii >35 microns; a moderate correlation is also found in QUE 97990. We suggest that impact-induced shear of a plum-pudding-like precursor produced the observed "mantles"; these were shielded from comminution during impact events by the adjacent stronger chondrules and inclusions. Some mantles in CM chondrites with low degrees of alteration show distinct layers that may largely reflect differences in porosity. Typically, a gray, uniform inner layer is surrounded by an outer layer consisting of darker silicates with BSE-bright speckles. The CM-chondrite objects characterized as "primary accretionary rocks" by Metzler et al. did not form in the nebula, but rather on the parent body. The absence of solar-flare particle tracks and solar-wind-implanted rare gases in these clasts reflect their lithified nature and low surface/volume ratios during the period when they resided in the regolith and were subject to irradiation by solar particles. The clasts are analogous to the light-colored metamorphosed clasts in ordinary-chondrite regolith breccias (which also lack solar-flare particle tracks and solar-wind gas).

The Valence of Iron in CM Chondrite Serpentine as Measured by Synchrotron Xanes

NASA Technical Reports Server (NTRS)

Mikouchi, T.; Zolensky, Michael E.; Satake, W.; Le, L.

2012-01-01

Fe-bearing phyllosilicates are the dominant product of aqueous alteration in carbonaceous chondrites, and serpentine is the most abundant phyllosilicate in CM2 chondrites that are the most abundant carbonaceous chondrite. Browning et al. predicted that Fe(3+)/(sum of Fe) ratios of serpentine in CM chondrites should change with progressive alteration. They proposed that progressive CM alteration is best monitored by evaluating the progress of Si and Fe3+ substitutions that necessarily attend the transition from end-member cronstedtite to serpentine. Their proposed Mineralogic Alteration Index, 2-(Fe(3+)/(2-Si)), was intended to highlight and utilize the relevant ex-change information in the stoichiometric phyllosilicate formulas based upon the coupled substitution of 2(Fe(3+), Al) = Si + (Mg, Fe(2+)...) in serpentine. The value of this ratio increases as alteration proceeds. We always wanted to directly test Browning s pre-diction through actual measurements of the Fe3+ con-tent of serpentine at the micron scale appropriate to EPMA analyses (Zega et al. have measured it at much finer scale), and this test can now be made using Synchrotron Radiation X-ray Absorption Near-Edge Structure (SR-XANES). Thus, we have recently begun investigation with CMs that span a large portion of the range of observed aqueous alteration, and we first analyzed Murray, Nogoya, and ALH84029 by SR-XANES. However, we did not find clear correlation between Fe3+/(sum of Fe) ratios of serpentine and their alteration degrees. We thus analyzed serpentine in three more CMs and here report their Fe3+/(sum of Fe) ratios in comparison with our previous results.

Aqueous Cleaning and Validation for Space Shuttle Propulsion Hardware at the White Sands Test Facility

NASA Technical Reports Server (NTRS)

Hornung, Steven D.; Biesinger, Paul; Kirsch, Mike; Beeson, Harold; Leuders, Kathy

1999-01-01

The NASA White Sands Test Facility (WSTF) has developed an entirely aqueous final cleaning and verification process to replace the current chlorofluorocarbon (CFC) 113 based process. This process has been accepted for final cleaning and cleanliness verification of WSTF ground support equipment. The aqueous process relies on ultrapure water at 50 C (323 K) and ultrasonic agitation for removal of organic compounds and particulate. The cleanliness is verified bv determining the total organic carbon (TOC) content and filtration with particulate counting. The effectiveness of the aqueous methods for detecting hydrocarbon contamination and particulate was compared to the accepted CFC 113 sampling procedures. Testing with known contaminants, such as hydraulic fluid and cutting and lubricating oils, to establish a correlation between aqueous TOC and CFC 113 nonvolatile residue (NVR) was performed. Particulate sampling on cleaned batches of hardware that were randomly separated and sampled by the two methods was performed. This paper presents the approach and results, and discusses the issues in establishing the equivalence of aqueous sampling to CFC 113 sampling, while describing the approach for implementing aqueous techniques on Space Shuttle Propulsion hardware.

Modifying optical properties of reduced/graphene oxide with controlled ozone and thermal treatment in aqueous suspensions.

PubMed

Hasan, Md Tanvir; Senger, Brian J; Mulford, Price; Ryan, Conor; Doan, Hung; Gryczynski, Zygmunt; Naumov, Anton V

2017-02-10

Graphene possesses a number of advantageous properties, however, does not exhibit optical emission, which limits its use in optoelectronics. Unlike graphene, its functional derivative, graphene oxide (GO) exhibits fluorescence emission throughout the visible. Here, we focus on controlled methods for tuning the optical properties of GO. We introduce ozone treatment of reduced graphene oxide (RGO) in order to controllably transform it from non-emissive graphene-like material into GO with a specific fluorescence emission response. Solution-based treatment of RGO for 5-45 min with ∼1.2 g l -1 ozone/oxygen gas mixture yields a drastic color change, bleaching of the absorption in the visible and the stepwise increase in fluorescence intensity and lifetime. This is attributed to the introduction of oxygen-containing functional groups to RGO graphitic platform as detected by the infrared spectroscopy. A reverse process: controllable quenching of this fluorescence is achieved by the thermal treatment of GO in aqueous suspension up to 90 °C. This methodology allows for the wide range alteration of GO optical properties starting from the dark-colored non-emissive RGO material up to nearly transparent highly ozone-oxidized GO showing substantial fluorescence emission. The size of the GO flakes is concomitantly altered by oxidation-induced scission. Semi-empirical PM3 theoretical calculations on HyperChem models are utilized to explore the origins of optical response from GO. Two models are considered, attributing the induced emission either to the localized states produced by oxygen-containing addends or the islands of graphitic carbon enclosed by such addends. Band gap values calculated from the models are in the agreement with experimentally observed transition peak maxima. The controllable variation of GO optical properties in aqueous suspension by ozone and thermal treatments shown in this work provides a route to tune its optical response for particular optoelectronics or biomedical applications.

Modifying optical properties of reduced/graphene oxide with controlled ozone and thermal treatment in aqueous suspensions

NASA Astrophysics Data System (ADS)

Tanvir Hasan, Md; Senger, Brian J.; Mulford, Price; Ryan, Conor; Doan, Hung; Gryczynski, Zygmunt; Naumov, Anton V.

2017-02-01

Graphene possesses a number of advantageous properties, however, does not exhibit optical emission, which limits its use in optoelectronics. Unlike graphene, its functional derivative, graphene oxide (GO) exhibits fluorescence emission throughout the visible. Here, we focus on controlled methods for tuning the optical properties of GO. We introduce ozone treatment of reduced graphene oxide (RGO) in order to controllably transform it from non-emissive graphene-like material into GO with a specific fluorescence emission response. Solution-based treatment of RGO for 5-45 min with ˜1.2 g l-1 ozone/oxygen gas mixture yields a drastic color change, bleaching of the absorption in the visible and the stepwise increase in fluorescence intensity and lifetime. This is attributed to the introduction of oxygen-containing functional groups to RGO graphitic platform as detected by the infrared spectroscopy. A reverse process: controllable quenching of this fluorescence is achieved by the thermal treatment of GO in aqueous suspension up to 90 °C. This methodology allows for the wide range alteration of GO optical properties starting from the dark-colored non-emissive RGO material up to nearly transparent highly ozone-oxidized GO showing substantial fluorescence emission. The size of the GO flakes is concomitantly altered by oxidation-induced scission. Semi-empirical PM3 theoretical calculations on HyperChem models are utilized to explore the origins of optical response from GO. Two models are considered, attributing the induced emission either to the localized states produced by oxygen-containing addends or the islands of graphitic carbon enclosed by such addends. Band gap values calculated from the models are in the agreement with experimentally observed transition peak maxima. The controllable variation of GO optical properties in aqueous suspension by ozone and thermal treatments shown in this work provides a route to tune its optical response for particular optoelectronics or biomedical applications.

K, U, and Th behavior in Martian environmental conditions

NASA Technical Reports Server (NTRS)

Zolotov, M. YU.; Krot, T. V.; Moroz, L. V.

1993-01-01

The possibility of K, U, and Th content determination from orbit and in situ allows consideration of those elements as geochemical indicators in the planetary studies. In the case of Mars the unambiguous interpretations of such data in terms of igneous rocks are remarkably constrained by the widespread rock alteration and the existence of exogenic deposits. Besides, the terrestrial experience indicates that K, U, and Th contents could be used as indicators of environmental geochemical processes. Thus the determination of K, U, and Th contents in the Martian surface materials could provide the indirect data on the conditions of some exogenic geological processes. The speculations on the K, U, and Th behavior in the Martian environments show that aeolian and aqueous processes leads to the preferential accumulation of K, U, and Th in fine dust material. The separation of K, U, and Th on Mars is smaller in scale to that on Earth.

Workshop on Oxygen in Asteroids and Meteorites

NASA Technical Reports Server (NTRS)

2005-01-01

Contents include the following: Constraints on the detection of solar nebula's oxidation state through asteroid observation. Oxidation/Reduction Processes in Primitive Achondrites. Low-Temperature Chemical Processing on Asteroids. On the Formation Location of Asteroids and Meteorites. The Spectral Properties of Angritic Basalts. Correlation Between Chemical and Oxygen Isotopic Compositions in Chondrites. Effect of In-Situ Aqueous Alteration on Thermal Model Heat Budgets. Oxidation-Reduction in Meteorites: The Case of High-Ni Irons. Ureilite Atmospherics: Coming up for Air on a Parent Body. High Temperature Effects Including Oxygen Fugacity, in Pre-Planetary and Planetary Meteorites and Asteroids. Oxygen Isotopic Variation of Asteroidal Materials. High-Temperature Chemical Processing on Asteroids: An Oxygen Isotope Perspective. Oxygen Isotopes and Origin of Opaque Assemblages from the Ningqiang Carbonaceous Chondrite. Water Distribution in the Asteroid Belt. Comparative Planetary Mineralogy: V Systematics in Planetary Pyroxenes and fo 2 Estimates for Basalts from Vesta.

3-D-Observation of Matrix of MIL 090657 Meteorite by Absorption-Phase Tomography

NASA Technical Reports Server (NTRS)

Miyama, Sugimoto; Tsuchiyama, Akira; Matsuno, Junya; Miyake, Akira; Nakano, Tsukasa; Uesugi, Kentaro; Takeuchi, Akihisa; Takigawa, Aki; Takayama, Akiko; Nakamura-Messenger, Keiko;

The Mars Orbital Catalog of Hydrated Alteration Signatures (MOCHAS): keeping track of ancient Mars's blanketing aqueous alteration

NASA Astrophysics Data System (ADS)

Carter, John

2016-04-01

The orbital and in-situ analysis of aqueous minerals on Mars is a recent research field which has given new momentum to the search for past life on Mars. These minerals, if found in preserved geologic contexts, also have the potential to decipher the past climatic conditions of Early Mars and probe its geological evolution. Despite terabytes of data and refined observations accumulated for over a decade, progress in those fields has been tedious. The highly degraded morphologic context, intrinsic limitations of orbital spectroscopy and highly localized nature of in-situ missions are major issues. Many highly detailed geological studies have been carried out at tens of locations on Mars, which have somewhat refined the global paradigm proposed in [Bibring et al., 2006], but no consensus exists as to the timing for the bulk of alteration (Pre/Noachian to LN/EH) nor the state of the water (meteoritic, climate mediated; or dominantly closed-system). In practice, the paucity of clear trends noticeable from the large datasets of near-infrared instruments (OMEGA, CRISM) has hampered efforts to test specific, global-scale alteration hypotheses. Other major fields of Mars research have tackled this issue by providing comprehensive databases with controlled biases, such as for channel networks, open-basin paleo-lakes or anhydrous chloride salts. Here we propose to apply the same approach to the OMEGA and CRISM datasets by providing a global and detailed compositional map of aqueous minerals on Mars. This catalog (MOCHAS) has several goals: i) provide for the first time a statistically viable approach to aqueous mineral detections on Mars, ii) provide regional context to help interpret and broaden the implications of numerous local-scale studies, iii) identify previously un-observed deposits of minerals of interest coupled to a well-preserved geologic context, iv) identify new candidate landing sites for future rovers and foster complementary/higher-resolution observations with instruments on current and upcoming probes. This new product adopts a mapping approach to all aqueous mineral detections on Mars, moving away from discrete catalogs of points available in previous attempts [Carter et al., 2013], which allows a statistical inference of their distribution, ages and other physical quantities. Classification of the deposits into major spectral classes will provide composition. The first version to be distributed in the near term will be presented, subsequent releases will provide refined characteristics for the deposits (mineralogical, physical and geological), and are foreseen to improve thanks to inputs from the community.

Natural Fumarolic Alteration of Fluorapatite, Olivine, and Basaltic Glass, and Implications for Habitable Environments on Mars

PubMed Central

Tschauner, Oliver

2013-01-01

Abstract Fumaroles represent a very important potential habitat on Mars because they contain water and nutrients. Global deposition of volcanic sulfate aerosols may also have been an important soil-forming process affecting large areas of Mars. Here we identify alteration from the Senator fumarole, northwest Nevada, USA, and in low-temperature environments near the fumarole to help interpret fumarolic and acid vapor alteration of rocks and soils on Mars. We analyzed soil samples and fluorapatite, olivine, and basaltic glass placed at and near the fumarole in in situ mineral alteration experiments designed to measure weathering under natural field conditions. Using synchrotron X-ray diffraction, we clearly observe hydroxyl-carbonate-bearing fluorapatite as a fumarolic alteration product of the original material, fluorapatite. The composition of apatites as well as secondary phosphates has been previously used to infer magmatic conditions as well as fumarolic conditions on Mars. To our knowledge, the observations reported here represent the first documented instance of formation of hydroxyl-carbonate-bearing apatite from fluorapatite in a field experiment. Retreat of olivine surfaces, as well as abundant NH4-containing minerals, was also characteristic of fumarolic alteration. In contrast, alteration in the nearby low-temperature environment resulted in formation of large pits on olivine surfaces, which were clearly distinguishable from the fumarolic alteration. Raman signatures of some fumarolically impacted surfaces are consistent with detection of the biological molecules chlorophyll and scytenomin, potentially useful biosignatures. Observations of altered minerals on Mars may therefore help identify the environment of formation and understand the aqueous history and potential habitability of that planet. Key Words: Fumaroles—Mars—Olivine—Acidophile—Geothermal—Search for life (biosignatures)—Synchrotron X-ray diffraction. Astrobiology 13, 1049–1064. PMID:24283927

Elucidating Complex Surface Reconstructions with Atomic-Resolution Scanning Tunneling Microscopy: Au(100)-Aqueous Electrochemical Interface

DTIC Science & Technology

1992-05-01

that unusually high-quality STM data of this type 5-7can be obtained at ordered gold -aqueous interfaces. Reconstruction is seen 2 to be triggered on...all three low-index gold surfaces by altering the potential to values corresponding to small (10-15 pC cm-2 ) negative surface electronic 5-7 charges...connections. The former was platinum and the latter was a freshly electrooxidized gold wire. All electrode potentials quoted here, however, are

Non-aqueous solution preparation of doped and undoped Li{sub x}Mn{sub y}O{sub z}

DOEpatents

Boyle, T.J.; Voigt, J.A.

1997-05-20

A method is described for generation of phase-pure doped and undoped Li{sub x}Mn{sub y}O{sub z} precursors. The method of this invention uses organic solutions instead of aqueous solutions or nonsolution ball milling of dry powders to produce phase-pure precursors. These precursors can be used as cathodes for lithium-polymer electrolyte batteries. Dopants may be homogeneously incorporated to alter the characteristics of the powder. 1 fig.

Aqueous cleaning and verification processes for precision cleaning of small parts

NASA Technical Reports Server (NTRS)

Allen, Gale J.; Fishell, Kenneth A.

1995-01-01

The NASA Kennedy Space Center (KSC) Materials Science Laboratory (MSL) has developed a totally aqueous process for precision cleaning and verification of small components. In 1990 the Precision Cleaning Facility at KSC used approximately 228,000 kg (500,000 lbs) of chlorofluorocarbon (CFC) 113 in the cleaning operations. It is estimated that current CFC 113 usage has been reduced by 75 percent and it is projected that a 90 percent reduction will be achieved by the end of calendar year 1994. The cleaning process developed utilizes aqueous degreasers, aqueous surfactants, and ultrasonics in the cleaning operation and an aqueous surfactant, ultrasonics, and Total Organic Carbon Analyzer (TOCA) in the nonvolatile residue (NVR) and particulate analysis for verification of cleanliness. The cleaning and verification process is presented in its entirety, with comparison to the CFC 113 cleaning and verification process, including economic and labor costs/savings.

Aqueous stream characterization from biomass fast pyrolysis and catalytic fast pyrolysis

DOE PAGES

Black, Brenna A.; Michener, William E.; Ramirez, Kelsey J.; ...

2016-09-05

Here, biomass pyrolysis offers a promising means to rapidly depolymerize lignocellulosic biomass for subsequent catalytic upgrading to renewable fuels. Substantial efforts are currently ongoing to optimize pyrolysis processes including various fast pyrolysis and catalytic fast pyrolysis schemes. In all cases, complex aqueous streams are generated containing solubilized organic compounds that are not converted to target fuels or chemicals and are often slated for wastewater treatment, in turn creating an economic burden on the biorefinery. Valorization of the species in these aqueous streams, however, offers significant potential for substantially improving the economics and sustainability of thermochemical biorefineries. To that end, heremore » we provide a thorough characterization of the aqueous streams from four pilot-scale pyrolysis processes: namely, from fast pyrolysis, fast pyrolysis with downstream fractionation, in situ catalytic fast pyrolysis, and ex situ catalytic fast pyrolysis. These configurations and processes represent characteristic pyrolysis processes undergoing intense development currently. Using a comprehensive suite of aqueous-compatible analytical techniques, we quantitatively characterize between 12 g kg -1 of organic carbon of a highly aqueous catalytic fast pyrolysis stream and up to 315 g kg -1 of organic carbon present in the fast pyrolysis aqueous streams. In all cases, the analysis ranges between 75 and 100% of mass closure. The composition and stream properties closely match the nature of pyrolysis processes, with high contents of carbohydrate-derived compounds in the fast pyrolysis aqueous phase, high acid content in nearly all streams, and mostly recalcitrant phenolics in the heavily deoxygenated ex situ catalytic fast pyrolysis stream. Overall, this work provides a detailed compositional analysis of aqueous streams from leading thermochemical processes -- analyses that are critical for subsequent development of selective valorization strategies for these waste streams.« less

Aqueous stream characterization from biomass fast pyrolysis and catalytic fast pyrolysis

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

Black, Brenna A.; Michener, William E.; Ramirez, Kelsey J.

Here, biomass pyrolysis offers a promising means to rapidly depolymerize lignocellulosic biomass for subsequent catalytic upgrading to renewable fuels. Substantial efforts are currently ongoing to optimize pyrolysis processes including various fast pyrolysis and catalytic fast pyrolysis schemes. In all cases, complex aqueous streams are generated containing solubilized organic compounds that are not converted to target fuels or chemicals and are often slated for wastewater treatment, in turn creating an economic burden on the biorefinery. Valorization of the species in these aqueous streams, however, offers significant potential for substantially improving the economics and sustainability of thermochemical biorefineries. To that end, heremore » we provide a thorough characterization of the aqueous streams from four pilot-scale pyrolysis processes: namely, from fast pyrolysis, fast pyrolysis with downstream fractionation, in situ catalytic fast pyrolysis, and ex situ catalytic fast pyrolysis. These configurations and processes represent characteristic pyrolysis processes undergoing intense development currently. Using a comprehensive suite of aqueous-compatible analytical techniques, we quantitatively characterize between 12 g kg -1 of organic carbon of a highly aqueous catalytic fast pyrolysis stream and up to 315 g kg -1 of organic carbon present in the fast pyrolysis aqueous streams. In all cases, the analysis ranges between 75 and 100% of mass closure. The composition and stream properties closely match the nature of pyrolysis processes, with high contents of carbohydrate-derived compounds in the fast pyrolysis aqueous phase, high acid content in nearly all streams, and mostly recalcitrant phenolics in the heavily deoxygenated ex situ catalytic fast pyrolysis stream. Overall, this work provides a detailed compositional analysis of aqueous streams from leading thermochemical processes -- analyses that are critical for subsequent development of selective valorization strategies for these waste streams.« less

Polyhedral Serpentine Grains in CM Chondrites

NASA Technical Reports Server (NTRS)

Zega, Thomas J.; Garvie, Laurence A. J.; Dodony, Istvan; Stroud, Rhonda M.; Buseck, Peter R.

2005-01-01

CM chondrites are primitive rocks that experienced aqueous alteration in the early solar system. Their matrices and fine-grained rims (FGRs) sustained the effects of alteration, and the minerals within them hold clues to the aqueous reactions. Sheet silicates are an important product of alteration, and those of the serpentine group are abundant in the CM2 chondrites. Here we expand on our previous efforts to characterize the structure and chemistry of serpentines in CM chondrites and report results on a polyhedral form that is structurally similar to polygonal serpentine. Polygonal serpentine consists of tetrahedral (T) sheets joined to M(2+)-centered octahedral (O) sheets (where (M2+) is primarily Mg(2+) and Fe(2+)), which give rise to a 1:1 (TO) layered structure with a 0.7-nm layer periodicity. The structure is similar to chrysotile in that it consists of concentric lizardite layers wrapped around the fiber axis. However, unlike the rolled-up chrysotile, the tetrahedral sheets of the lizardite layers are periodically inverted and kinked, producing sectors. The relative angles between sectors result in 15- and 30-sided polygons in terrestrial samples.

Guava extract (Psidium guajava) alters the labelling of blood constituents with technetium-99m*

PubMed Central

Abreu, P.R.C.; Almeida, M.C.; Bernardo, R.M.; Bernardo, L.C.; Brito, L.C.; Garcia, E.A.C.; Fonseca, A.S.; Bernardo-Filho, M.

2006-01-01

Psidium guajava (guava) leaf is a phytotherapic used in folk medicine to treat gastrointestinal and respiratory disturbances and is used as anti-inflammatory medicine. In nuclear medicine, blood constituents (BC) are labelled with technetium-99m (99mTc) and used to image procedures. However, data have demonstrated that synthetic or natural drugs could modify the labelling of BC with 99mTc. The aim of this work was to evaluate the effects of aqueous extract of guava leaves on the labelling of BC with 99mTc. Blood samples of Wistar rats were incubated with different concentrations of guava extract and labelled with 99mTc after the percentage of incorporated radioactivity (%ATI) in BC was determined. The results suggest that aqueous guava extract could present antioxidant action and/or alters the membrane structures involved in ion transport into cells, thus decreasing the radiolabelling of BC with 99mTc. The data showed significant (P<0.05) alteration of ATI in BC from blood incubated with guava extract. PMID:16691636

Ceramic electrolyte coating and methods

DOEpatents

Seabaugh, Matthew M [Columbus, OH; Swartz, Scott L [Columbus, OH; Dawson, William J [Dublin, OH; McCormick, Buddy E [Dublin, OH

2007-08-28

Aqueous coating slurries useful in depositing a dense coating of a ceramic electrolyte material (e.g., yttrium-stabilized zirconia) onto a porous substrate of a ceramic electrode material (e.g., lanthanum strontium manganite or nickel/zirconia) and processes for preparing an aqueous suspension of a ceramic electrolyte material and an aqueous spray coating slurry including a ceramic electrolyte material. The invention also includes processes for depositing an aqueous spray coating slurry including a ceramic electrolyte material onto pre-sintered, partially sintered, and unsintered ceramic substrates and products made by this process.

Fibrous scaffolds fabricated by emulsion electrospinning: from hosting capacity to in vivo biocompatibility

NASA Astrophysics Data System (ADS)

Spano, F.; Quarta, A.; Martelli, C.; Ottobrini, L.; Rossi, R. M.; Gigli, G.; Blasi, L.

2016-04-01

Electrospinning is a versatile method for preparing functional three-dimensional scaffolds. Synthetic and natural polymers have been used to produce micro- and nanofibers that mimic extracellular matrices. Here, we describe the use of emulsion electrospinning to prepare blended fibers capable of hosting aqueous species and releasing them in solution. The existence of an aqueous and a non-aqueous phase allows water-soluble molecules to be introduced without altering the structure and the degradation of the fibers, and means that their release properties under physiological conditions can be controlled. To demonstrate the loading capability and flexibility of the blend, various species were introduced, from magnetic nanoparticles and quantum rods to biological molecules. Cellular studies showed the spontaneous adhesion and alignment of cells along the fibers. Finally, in vivo experiments demonstrated the high biocompatibility and safety of the scaffolds up to 21 days post-implantation.Electrospinning is a versatile method for preparing functional three-dimensional scaffolds. Synthetic and natural polymers have been used to produce micro- and nanofibers that mimic extracellular matrices. Here, we describe the use of emulsion electrospinning to prepare blended fibers capable of hosting aqueous species and releasing them in solution. The existence of an aqueous and a non-aqueous phase allows water-soluble molecules to be introduced without altering the structure and the degradation of the fibers, and means that their release properties under physiological conditions can be controlled. To demonstrate the loading capability and flexibility of the blend, various species were introduced, from magnetic nanoparticles and quantum rods to biological molecules. Cellular studies showed the spontaneous adhesion and alignment of cells along the fibers. Finally, in vivo experiments demonstrated the high biocompatibility and safety of the scaffolds up to 21 days post-implantation. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr00782a

Hepatoprotective and immunomodulatory properties of aqueous extract of Curcuma longa in carbon tetra chloride intoxicated Swiss albino mice.

PubMed

Sengupta, Mahuya; Sharma, Gauri Dutta; Chakraborty, Biswajit

2011-06-01

To evaluate the hepatoprotective and immunotherapeutic effects of aqueous extract of turmeric rhizome in CCl4 intoxicated Swiss albino mice. First group of mice (n=5) received CCl4 treatment at a dose of 0.5 mL/kg bw (i.p.) for 7 days. Second group was fed orally the aqueous extract of turmeric at a dose of 50 mg/kg bw for 15 days. The third group was given both the turmeric extract (for 15 days, orally) and CCl4 (for last 7 days, i.p.). The fourth group was kept as a control. To study the liver function, the transaminase enzymes (SGOT and SGPT) and bilirubin level were measured in the serum of respective groups. For assaying the immunotherapeutic action of Curcuma longa (C. longa), non specific host response parameters like morphological alteration, phagocytosis, nitric oxide release, myeloperoxidase release and intracellular killing capacity of peritoneal macrophages were studied from the respective groups. The result of present study suggested that CCl4 administration increased the level of SGOT and SGPT and bilirubin level in serum. However, the aqueous extract of turmeric reduced the level of SGOT, SGPT and bilirubin in CCl4 intoxicated mice. Apart from damaging the liver system, CCl4 also reduced non specific host response parameters like morphological alteration, phagocytosis, nitric oxide release, myeloperoxidase release and intracellular killing capacity of peritoneal macrophages. Administration of aqueous extract of C. longa offered significant protection from these damaging actions of CCl4 on the non specific host response in the peritoneal macrophages of CCl4 intoxicated mice. In conclusion, the present study suggests that C. longa has immunotherapeutic properties along with its ability to ameliorate hepatotoxicity.

Hepatoprotective and immunomodulatory properties of aqueous extract of Curcuma longa in carbon tetra chloride intoxicated Swiss albino mice

PubMed Central

Sengupta, Mahuya; Sharma, Gauri Dutta; Chakraborty, Biswajit

2011-01-01

Objective To evaluate the hepatoprotective and immunotherapeutic effects of aqueous extract of turmeric rhizome in CCl4 intoxicated Swiss albino mice. Methods First group of mice (n=5) received CCl4 treatment at a dose of 0.5 mL/kg bw (i.p.) for 7 days. Second group was fed orally the aqueous extract of turmeric at a dose of 50 mg/kg bw for 15 days. The third group was given both the turmeric extract (for 15 days, orally) and CCl4 (for last 7 days, i.p.). The fourth group was kept as a control. To study the liver function, the transaminase enzymes (SGOT and SGPT) and bilirubin level were measured in the serum of respective groups. For assaying the immunotherapeutic action of Curcuma longa (C. longa), non specific host response parameters like morphological alteration, phagocytosis, nitric oxide release, myeloperoxidase release and intracellular killing capacity of peritoneal macrophages were studied from the respective groups. Results The result of present study suggested that CCl4 administration increased the level of SGOT and SGPT and bilirubin level in serum. However, the aqueous extract of turmeric reduced the level of SGOT, SGPT and bilirubin in CCl4 intoxicated mice. Apart from damaging the liver system, CCl4 also reduced non specific host response parameters like morphological alteration, phagocytosis, nitric oxide release, myeloperoxidase release and intracellular killing capacity of peritoneal macrophages. Administration of aqueous extract of C. longa offered significant protection from these damaging actions of CCl4 on the non specific host response in the peritoneal macrophages of CCl4 intoxicated mice. Conclusions In conclusion, the present study suggests that C. longa has immunotherapeutic properties along with its ability to ameliorate hepatotoxicity. PMID:23569758

Analysis of a whole diet in terms of phenolic content and antioxidant capacity: effects of a simulated gastrointestinal digestion.

PubMed

Koehnlein, Eloá Angélica; Koehnlein, Érica Marcela; Corrêa, Rúbia Carvalho Gomes; Nishida, Verônica Sayuri; Correa, Vanesa Gesser; Bracht, Adelar; Peralta, Rosane Marina

2016-09-01

This work compares the phenolic contents and the total antioxidant capacity of the 36 most popular Brazilian foods submitted to aqueous extraction or in vitro digestion. The purpose was to evaluate the extent by which digestion differs from the simple aqueous extraction procedures of several food matrices. After in vitro digestion, cereals, legumes, vegetables, tuberous vegetables, chocolates and fruits showed higher phenolic contents and higher antioxidant activities than those obtained by aqueous extraction. Contrarily, the digestion caused a reduction in the phenolic contents and antioxidant activities of beverages (red wine, coffee and yerba mate). Our results suggest that the phenolics of food groups with solid and complex matrix are protected against enzymatic action and alteration in pH during the digestion, what does not occur in liquid food matrices such as the beverages. This fact would overestimate the antioxidant activities of beverages submitted solely to aqueous extraction.

Using solid phase micro extraction to determine salting-out (Setschenow) constants for hydrophobic organic chemicals.

PubMed

Jonker, Michiel T O; Muijs, Barry

2010-06-01

With increasing ionic strength, the aqueous solubility and activity of organic chemicals are altered. This so-called salting-out effect causes the hydrophobicity of the chemicals to be increased and sorption in the marine environment to be more pronounced than in freshwater systems. The process can be described with empirical salting-out or Setschenow constants, which traditionally are determined by comparing aqueous solubilities in freshwater and saline water. Aqueous solubilities of hydrophobic organic chemicals (HOCs) however are difficult to determine, which might partly explain the limited size of the existing data base on Setschenow constants for these chemicals. In this paper, we propose an alternative approach for determining the constants, which is based on the use of solid phase micro extraction (SPME) fibers. Partitioning of polycyclic aromatic hydrocarbons (PAHs) to SPME fibers increased about 1.7 times when going from de-ionized water to seawater. From the log-linear relationship between SPME fiber-water partition coefficients and ionic strength, Setschenow constants were derived, which measured on average 0.35 L mol(-1). These values agreed with literature values existing for some of the investigated PAHs and were independent of solute hydrophobicity or molar volume. Based on the present data, SPME seems to be a convenient and suitable alternative technique to determine Setschenow constants for HOCs. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

Determination of soluble and insoluble dietary fiber in psyllium-containing cereal products.

PubMed

Lee, S C; Rodriguez, F; Storey, M; Farmakalidis, E; Prosky, L

1995-01-01

A method for soluble and insoluble dietary fiber determinations was developed for psyllium-containing food products, which are highly viscous in aqueous solutions. The assay is based on a modification of the AOAC soluble and insoluble dietary fiber method (991.43), which was recommended for nutrition labeling in the final U.S. food labeling regulations. We found that method 991.43 and other existing dietary fiber methods could not be applied to psyllium food products, which exhibit high viscosity in aqueous solutions, because highly viscous solutions could not be filtered easily. In this study, we modified AOAC method 991.43 to accommodate the filtration process of viscous sample solutions. Sonication followed by high-speed centrifugation was used before filtration. The principles of the method are similar to those for AOAC method 991.43, including the use of the same 3 enzymes (heat-stable alpha-amylase, protease, and amyloglucosidase) as well as similar enzyme incubation conditions. The modification using sonication and high-speed centrifugation did not alter the method performance for analytically normal products such as wheat bran, oat bran, and soy fiber. Yet, the modification allowed the separation of soluble dietary fiber fractions from insoluble fractions for psyllium products with satisfactory precision. This method for psyllium dietary fiber determinations may be applied to other food products that exhibit high viscosity in aqueous solutions.

SEPARATION OF SCANDIUM VALUES FORM IRON VALUES BY SOLVENT EXTRACTION

DOEpatents

Kuhlman, C.W. Jr.; Lang, G.P.

1961-12-19

A process is given for separating scandium from trivalent iron values. In this process, an aqueous nitric acid solution is contacted with a water- immiscible alkyl phosphate solution, the aqueous solution containing the values to be separated, whereby the scandium is taken up by the alkyl phosphate. The aqueous so1ution is preferably saturated with magnesium nitrate to retain the iron in the aqueous solution. (AEC)

CO2 adhesion on hydrated mineral surfaces.

PubMed

Wang, Shibo; Tao, Zhiyuan; Persily, Sara M; Clarens, Andres F

2013-10-15

Hydrated mineral surfaces in the environment are generally hydrophilic but in certain cases can strongly adhere CO2, which is largely nonpolar. This adhesion can significantly alter the wettability characteristics of the mineral surface and consequently influence capillary/residual trapping and other multiphase flow processes in porous media. Here, the conditions influencing adhesion between CO2 and homogeneous mineral surfaces were studied using static pendant contact angle measurements and captive advancing/receding tests. The prevalence of adhesion was sensitive to both surface roughness and aqueous chemistry. Adhesion was most widely observed on phlogopite mica, silica, and calcite surfaces with roughness on the order of ~10 nm. The incidence of adhesion increased with ionic strength and CO2 partial pressure. Adhesion was very rarely observed on surfaces equilibrated with brines containing strong acid or base. In advancing/receding contact angle measurements, adhesion could increase the contact angle by a factor of 3. These results support an emerging understanding of adhesion of, nonpolar nonaqueous phase fluids on mineral surfaces influenced by the properties of the electrical double layer in the aqueous phase film and surface functional groups between the mineral and CO2.

Distribution of Aliphatic Amines in CO, CV, and CK Carbonaceous Chondrites and Relation to Mineralogy and Processing History

NASA Technical Reports Server (NTRS)

Aponte, Jose C.; Abreu, Neyda M.; Glavin, Daniel P.; Dworkin, Jason P.; Elsila, Jamie E.

2017-01-01

The analysis of water-soluble organic compounds in meteorites provides valuable insights into the prebiotic synthesis of organic matter and the processes that occurred during the formation of the solar system. We investigated the concentration of aliphatic monoamines present in hot acid water extracts of the unaltered Antarctic carbonaceous chondrites, Dominion Range (DOM) 08006 (CO3) and Miller Range (MIL) 05013 (CO3), and the thermally altered meteorites, Allende (CV3), LAP 02206 (CV3), GRA 06101 (CV3), Allan Hills (ALH) 85002 (CK4), and EET 92002 (CK5). We have also reviewed and assessed the petrologic characteristics of the meteorites studied here to evaluate the effects of asteroidal processing on the abundance and molecular distributions of monoamines. The CO3, CV3, CK4, and CK5 meteorites studied here contain total concentrations of amines ranging from 1.2 to 4.0 nmol/g of meteorite; these amounts are 1-3 orders of magnitude below those observed in carbonaceous chondrites from the CI, CM, and CR groups. The low-amine abundances for CV and CK chondrites may be related to their extensive degree of thermal metamorphism and/or to their low original amine content. Although the CO3 meteorites, DOM 08006 and MIL 05013, do not show signs of thermal and aqueous alteration, their monoamine contents are comparable to those observed in moderately/extensively thermally altered CV3, CK4, and CK5 carbonaceous chondrites. The low content of monoamines in pristine CO carbonaceous chondrites suggests that the initial amounts, and not asteroidal processes, play a dominant role in the content of monoamines in carbonaceous chondrites. The primary monoamines, methylamine, ethylamine, and n-propylamine constitute the most abundant amines in the CO3, CV3, CK4, and CK5 meteorites studied here. Contrary to the predominance of n-x-amino acid isomers in CO3 and thermally altered meteorites, there appears to be no preference for the larger n-amines.

Searching for Biogeochemical Cycles on Mars

NASA Technical Reports Server (NTRS)

DesMarais, David J.

1997-01-01

The search for life on Mars clearly benefits from a rigorous, yet broad, definition of life that compels us to consider all possible lines of evidence for a martian biosphere. Recent studies in microbial ecology illustrate that the classic definition of life should be expanded beyond the traditional definition of a living cell. The traditional defining characteristics of life are threefold. First, life is capable of metabolism, that is, it performs chemical reactions that utilize energy and also synthesize its cellular constituents. Second, life is capable of self-replication. Third, life can evolve in order to adapt to environmental changes. An expanded, ecological definition of life also recognizes that life is a community of organisms that must interact with their nonliving environment through processes called biogeochemical cycles. This regenerative processing maintains, in an aqueous conditions, a dependable supply of nutrients and energy for growth. In turn, life can significantly affect those processes that control the exchange of materials between the atmosphere, ocean, and upper crust. Because metabolic processes interact directly with the environment, they can alter their surroundings and thus leave behind evidence of life. For example, organic matter is produced from single-carbon-atom precursors for the biosynthesis of cellular constituents. This leads to a reservoir of reduced carbon in sediments that, in turn, can affect the oxidation state of the atmosphere. The harvesting of chemical energy for metabolism often employs oxidation-reduction reactions that can alter the chemistry and oxidation state of the redox-sensitive elements carbon, sulfur, nitrogen, iron, and manganese. Have there ever been biogeochemical cycles on Mars? Certain key planetary processes can offer clues. Active volcanism provides reduced chemical species that biota can use for organic synthesis. Volcanic carbon dioxide and methane can serve as greenhouse gases. Thus the persistence of volcanism on Mars may well have influenced the persistence of a martian biosphere. The geologic processing of the crust can affect the availability of nutrients and also control the deposition of minerals that could have served as a medium for the preservation of fossil information. Finally, the activity of liquid water is crucial to life. Was there ever an Earth-like hydrologic cycle with rainfall? Has aqueous activity instead been restricted principally to hydrothermal activity below the surface? To what extent did the inorganic chemistry driven by sunlight and hydrothermal activity influence organic chemistry (prebiotic chemical evolution)? This paper addresses these and other key questions.

Micelle-vesicle-micelle transition in aqueous solution of anionic surfactant and cationic imidazolium surfactants: Alteration of the location of different fluorophores.

PubMed

Dutta, Rupam; Ghosh, Surajit; Banerjee, Pavel; Kundu, Sangita; Sarkar, Nilmoni

2017-03-15

The presence of different surfactants can alter the physicochemical behaviors of aqueous organized assemblies. In this article, we have investigated the location of hydrophobic molecule (Coumarin 153, C153) and hydrophilic molecule (Rhodamine 6G perchlorate, R6G) during micelle-vesicle-micelle transition in aqueous medium in presence of anionic surfactant, sodium dodecylbenzenesulfonate (SDBS) and cationic imidazolium-based surfactant, 1-alkyl-3-methylimidazolium chloride (C n mimCl; n=12, 16). Initially, the physicochemical properties of anionic micellar solution of SDBS has been investigated in presence of imidazolium-based surfactant, C n mimCl (n=12, 16) in aqueous medium by visual observation, turbidity measurement, zeta potential (ζ), dynamics light scattering (DLS), and transmission electron microscopy (TEM). Zeta potential (ζ) measurement clearly indicates that the incorporation efficiency of C 16 mimCl in SDBS micelle is better than the other one due to the involvement of strong hydrophobic as well as electrostatic interaction between the two associated molecules. Turbidity and DLS measurements clearly suggest the formation of vesicles over a wide range of concentration. Finally, the rotational motion of C153 and R6G has also been monitored at different mole fractions of C n mimCl in SDBS-C n mimCl (n=12, 16) solution mixtures. The hydrophobic C153 molecules preferentially located in the bilayer region of vesicle, whereas hydrophilic R6G can be solubilized at surface of the bilayer, inner water pool or outer surface of vesicles. It is observed that rotational motion of R6G is altered significantly in SDBS-C n mimCl solution mixtures in presence of different mole fractions of C n mimCl. Additionally, the translational diffusion motion of R6G is monitored using fluorescence correlation spectroscopy (FCS) techniques to get a complete scenario about the location and translational diffusion of R6G. Copyright © 2016 Elsevier Inc. All rights reserved.

PROCESS OF SEPARATING URANIUM FROM AQUEOUS SOLUTION BY SOLVENT EXTRACTION

DOEpatents

Warf, J.C.

1958-08-19

A process is described for separating uranium values from aqueous uranyl nitrate solutions. The process consists in contacting the uramium bearing solution with an organic solvent, tributyl phosphate, preferably diluted with a less viscous organic liquida whereby the uranyl nitrate is extracted into the organic solvent phase. The uranvl nitrate may be recovered from the solvent phase bv back extracting with an aqueous mediuin.

Early aqueous activity on the ordinary and carbonaceous chondrite parent bodies recorded by fayalite

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

Doyle, Patricia M.; Jogo, Kaori; Nagashima, Kazuhide

Here, chronology of aqueous activity on chondrite parent bodies constrains their accretion times and thermal histories. Radiometric 53Mn– 53Cr dating has been successfully applied to aqueously formed carbonates in CM carbonaceous chondrites. Owing to the absence of carbonates in ordinary (H, L and LL), and CV and CO carbonaceous chondrites, and the lack of proper standards, there are no reliable ages of aqueous activity on their parent bodies. Here we report the first 53Mn– 53Cr ages of aqueously formed fayalite in the L3 chondrite Elephant Moraine 90161 as 2.4 +1.8 -1.3 Myr after calcium–aluminium-rich inclusions (CAIs), the oldest Solar Systemmore » solids. In addition, measurements using our synthesized fayalite standard show that fayalite in the CV3 chondrite Asuka 881317 and CO3-like chondrite MacAlpine Hills 88107 formed and 4.2 +0.8 -0.7 Myr after CAIs, respectively. Thermal modelling, combined with the inferred conditions (temperature and water/rock ratio) and 53Mn– 53Cr ages of aqueous alteration, suggests accretion of the L, CV and CO parent bodies ~1.8–2.5 Myr after CAIs.« less

Early aqueous activity on the ordinary and carbonaceous chondrite parent bodies recorded by fayalite

DOE PAGES

Doyle, Patricia M.; Jogo, Kaori; Nagashima, Kazuhide; ...

2015-06-23

Here, chronology of aqueous activity on chondrite parent bodies constrains their accretion times and thermal histories. Radiometric 53Mn– 53Cr dating has been successfully applied to aqueously formed carbonates in CM carbonaceous chondrites. Owing to the absence of carbonates in ordinary (H, L and LL), and CV and CO carbonaceous chondrites, and the lack of proper standards, there are no reliable ages of aqueous activity on their parent bodies. Here we report the first 53Mn– 53Cr ages of aqueously formed fayalite in the L3 chondrite Elephant Moraine 90161 as 2.4 +1.8 -1.3 Myr after calcium–aluminium-rich inclusions (CAIs), the oldest Solar Systemmore » solids. In addition, measurements using our synthesized fayalite standard show that fayalite in the CV3 chondrite Asuka 881317 and CO3-like chondrite MacAlpine Hills 88107 formed and 4.2 +0.8 -0.7 Myr after CAIs, respectively. Thermal modelling, combined with the inferred conditions (temperature and water/rock ratio) and 53Mn– 53Cr ages of aqueous alteration, suggests accretion of the L, CV and CO parent bodies ~1.8–2.5 Myr after CAIs.« less

Polymeric nanospheres as a displacement fluid in enhanced oil recovery

NASA Astrophysics Data System (ADS)

Hendraningrat, Luky; Zhang, Julien

2015-12-01

This paper presents the investigation of using nanoscale polyacrylamide-based spheres (nanospheres) as a displacement fluid in enhanced oil recovery (EOR). Coreflood experiments were conducted to evaluate the impact of nanospheres and its concentration dispersed in model formation water on oil recovery during a tertiary oil recovery process. The coreflood results showed that nanospheres can enhance residual oil recovery in the sandstone rock samples and its concentration showed a significant impact into incremental oil. By evaluating the contact angle, it was observed that wettability alteration also might be involved in the possible oil displacement mechanism in this process together with fluid behavior and permeability to water that might divert injected fluid into unswept oil areas and enhance the residual oil recovery. These investigations promote nanospheres aqueous disperse solution as a potential displacement fluid in EOR.

Removing sulphur oxides from a fluid stream

DOEpatents

Katz, Torsten; Riemann, Christian; Bartling, Karsten; Rigby, Sean Taylor; Coleman, Luke James Ivor; Lail, Marty Alan

2014-04-08

A process for removing sulphur oxides from a fluid stream, such as flue gas, comprising: providing a non-aqueous absorption liquid containing at least one hydrophobic amine, the liquid being incompletely miscible with water; treating the fluid stream in an absorption zone with the non-aqueous absorption liquid to transfer at least part of the sulphur oxides into the non-aqueous absorption liquid and to form a sulphur oxide-hydrophobic amine-complex; causing the non-aqueous absorption liquid to be in liquid-liquid contact with an aqueous liquid whereby at least part of the sulphur oxide-hydrophobic amine-complex is hydrolyzed to release the hydrophobic amine and sulphurous hydrolysis products, and at least part of the sulphurous hydrolysis products is transferred into the aqueous liquid; separating the aqueous liquid from the non-aqueous absorption liquid. The process mitigates absorbent degradation problems caused by sulphur dioxide and oxygen in flue gas.

Aqueous alteration detection in Tikhonravov crater, Mars

NASA Astrophysics Data System (ADS)

Mancarella, F.; Fonti, S.; Alemanno, G.; Orofino, V.; Blanco, A.

2018-03-01

The existence of a wet period lasting long enough to allow the development of elementary forms of life on Mars has always been a very interesting issue. Given this perspective, the research for geological markers of such occurrences has been continually pursued. Once a favorable site is detected, effort should be spent to get as much information as possible aimed at a precise assessment of the genesis and evolution of the areas showing the selected markers. In this work, we discuss the recent finding of possible deposits pointing to the past existence of liquid water in Tikhonravov crater located in Arabia Terra. Comparison of CRISM spectra and those of laboratory minerals formed by aqueous alteration has led us to the conclusion that the studied areas within the impact crater host phyllosilicates deposits. In addition, analysis of the CRISM spectra has resulted in the tentative identification of carbonates mixed with phyllosilicates.

Recent Results From the Opportunity Rover's Exploration of Endeavour Crater, Mars

NASA Technical Reports Server (NTRS)

Arvidson, R. E.; Squyres, S. W.; Gellert, R.; Mittlefehldt, D. W.

2014-01-01

The Mars Exploration Rover Opportunity is beginning its 11th year of exploration and as of sol 3535 (1/3/14 UTC) has traversed 38,729 m (based on wheel turns) across the plains of Meridiani and the rim of the approx. 22 km wide Noachian Endeavour Crater. Opportunity has investigated ancient sulfate-rich sand-stones (Burns formation) that dominate the plains and formed in ancient playa and dune environments, characterized impact breccias (Shoemaker formation) and their aqueous alteration on Endeavour's Cape York rim segment, and investigated extensive aqueous alteration of rocks on Cape York's Matijevic Hill that stratigraphically underlie Shoemaker formation and predate the Endeavour-forming event. In this abstract results from Opportunity's recent exploration of Endeavour's rim are covered, focusing on comparing what was found on Matijevic Hill with observations acquired on Murray Ridge, where Opportunity will spend its sixth winter at Cook Haven.

Oriented Mineral Transformation in a Dark Inclusion from the Leoville Meteorite

NASA Technical Reports Server (NTRS)

Buchanan, P. C.; Zolensky, M. E.; Weisberg, M. K.; Hagiya, K.; Mikouchi, T.; Takenouchi, A.; Hasegawa, H.; Ono, H.; Higashi, K.; Ohsumi, K.

2017-01-01

Dark inclusions (DIs) in chondrites and achondrites are dark gray to black fragments that include a wide variety of materials that have experienced very different petrologic histories. Based on the law of inclusions, they are rocks that accreted prior to and are older than their host meteorites and possibly rep-resent an earlier generation of material. The origin of these inclusions and their relationship to their host meteorites is not always clear. They are interesting in that they represent lithologies that experienced different parent body histories than their host meteorites and are either exotic components or originated from different regions of the meteorite parent body. In many cases, DIs in CV chondrites have been altered to greater degrees than their host meteorites suggesting pre accretionary alteration [e.g., 1,2,3]. There is debate concerning whether or not these DIs record an earlier era of aqueous alteration and subsequent thermal metamorphism, and how these processes may have also affected the host CV materials. The present study is a description of a dark inclusion found in the Leoville meteorite (specifically, thin section USNM 3535-1). This inclusion has some interesting features that have considerable relevance for this discussion.

Aqueous organic chemistry in the atmosphere: sources and chemical processing of organic aerosols.

PubMed

McNeill, V Faye

2015-02-03

Over the past decade, it has become clear that aqueous chemical processes occurring in cloud droplets and wet atmospheric particles are an important source of organic atmospheric particulate matter. Reactions of water-soluble volatile (or semivolatile) organic gases (VOCs or SVOCs) in these aqueous media lead to the formation of highly oxidized organic particulate matter (secondary organic aerosol; SOA) and key tracer species, such as organosulfates. These processes are often driven by a combination of anthropogenic and biogenic emissions, and therefore their accurate representation in models is important for effective air quality management. Despite considerable progress, mechanistic understanding of some key aqueous processes is still lacking, and these pathways are incompletely represented in 3D atmospheric chemistry and air quality models. In this article, the concepts, historical context, and current state of the science of aqueous pathways of SOA formation are discussed.

PROCESS OF REMOVING PLUTONIUM VALUES FROM SOLUTION WITH GROUP IVB METAL PHOSPHO-SILICATE COMPOSITIONS

DOEpatents

Russell, E.R.; Adamson, A.W.; Schubert, J.; Boyd, G.E.

1957-10-29

A process for separating plutonium values from aqueous solutions which contain the plutonium in minute concentrations is described. These values can be removed from an aqueous solution by taking an aqueous solution containing a salt of zirconium, titanium, hafnium or thorium, adding an aqueous solution of silicate and phosphoric acid anions to the metal salt solution, and separating, washing and drying the precipitate which forms when the two solutions are mixed. The aqueous plutonium containing solution is then acidified and passed over the above described precipi-tate causing the plutonium values to be adsorbed by the precipitate.

Assessment of Fenton's reagent and ozonation as pre-treatments for increasing the biodegradability of aqueous diethanolamine solutions from an oil refinery gas sweetening process.

PubMed

Durán-Moreno, A; García-González, S A; Gutiérrez-Lara, M R; Rigas, F; Ramírez-Zamora, R M

2011-02-28

The aim of this work was to evaluate the efficiency of three chemical oxidation processes for increasing the biodegradability of aqueous diethanolamine solutions (aqueous DEA solutions), to be used as pre-treatments before a biological process. The raw aqueous DEA solution, sourced from a sour gas sweetening plant at a Mexican oil refinery, was first characterized by standardized physico-chemical methods. Then experiments were conducted on diluted aqueous DEA solutions to test the effects of Fenton's reagent, ozone and ozone-hydrogen peroxide on the removal of some physicochemical parameters of these solutions. Lastly, biodegradability tests based on Dissolved Organic Carbon Die Away OECD301-A, were carried out on a dilution of the raw aqueous DEA solution and on the treated aqueous DEA solutions, produced by applying the best experimental conditions determined during the aforementioned oxidation tests. Experimental results showed that for aqueous DEA solutions treated with Fenton's reagent, the best degradation rate (70%) was obtained at pH 2.8, with Fe(2+) and H(2)O(2) at doses of 1000 and 10,000 mg/L respectively. In the ozone process, the best degradation (60%) was observed in aqueous DEA solution (100 mg COD/L), using 100 mg O(3)/L at pH 5. In the ozone-hydrogen peroxide process, no COD or DOC removals were observed. The diluted spent diethanolamine solution showed its greatest increase in biodegradability after a reaction period of 28 days when treated with Fenton's reagent, but after only 15 days in the case of ozonation. Copyright © 2011 Elsevier B.V. All rights reserved.

Comparison of particle sizes between 238PuO 2 before aqueous processing, after aqueous processing, and after ball milling

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

Mulford, Roberta Nancy

Particle sizes determined for a single lot of incoming Russian fuel and for a lot of fuel after aqueous processing are compared with particle sizes measured on fuel after ball-milling. The single samples of each type are believed to have particle size distributions typical of oxide from similar lots, as the processing of fuel lots is fairly uniform. Variation between lots is, as yet, uncharacterized. Sampling and particle size measurement methods are discussed elsewhere.

Polymer-assisted aqueous deposition of metal oxide films

DOEpatents

Li, DeQuan [Los Alamos, NM; Jia, Quanxi [Los Alamos, NM

2003-07-08

An organic solvent-free process for deposition of metal oxide thin films is presented. The process includes aqueous solutions of necessary metal precursors and an aqueous solution of a water-soluble polymer. After a coating operation, the resultant coating is fired at high temperatures to yield optical quality metal oxide thin films.

URANIUM SEPARATION PROCESS

DOEpatents

McVey, W.H.; Reas, W.H.

1959-03-10

The separation of uranium from an aqueous solution containing a water soluble uranyl salt is described. The process involves adding an alkali thiocyanate to the aqueous solution, contacting the resulting solution with methyl isobutyl ketons and separating the resulting aqueous and organic phase. The uranium is extracted in the organic phase as UO/sub 2/(SCN)/sub/.

Metamorphosed CM and CI Carbonaceous Chondrites Could Be from the Breakup of the Same Earth-crossing Asteroid

NASA Technical Reports Server (NTRS)

Zolensky, Michael; Abell, Paul; Tonui, Eric

2005-01-01

Far from being the relatively unprocessed materials they were once believed to be, we now know that a significant number of carbonaceous chondrites were thermally metamorphosed on their parent asteroid(s). Numerous studies indicate that 7 "CM" and 2 "CI" chondrites have been naturally heated, variously, at from 400 to over 700 C on their parent asteroid(s). Petrographic textures reveal that this thermal metamorphism occurred after the dominant aqueous alteration phase, although some meteorites show evidence of a heating event between two aqueous alteration episodes, i.e. pro- and retrograde aqueous alteration. Aside from the issues of the identification of the transient heat source, timing of metamorphism, and the relation of these materials (if any) to conventional CM and CI chondrites, there is also a mystery related to their recovery. All of these meteorites have been recovered from the Antarctic; none are falls or finds from anyplace else. Indeed, the majority have been collected by the Japanese NIPR field parties in the Yamato Mountains. In fact, one estimate is that these meteorites account for approx. 64 wt% of the CM carbonaceous chondrites at the NIPR. The reasons for this are unclear and might be due in part to simple sampling bias. However we suggest that this recovery difference is related to the particular age of the Yamato Mountains meteorite recovery surfaces, and differences in meteoroid fluxes between the Yamato meteorites and recent falls and substantially older Antarctic meteorites. Additional information is included in the original extended abstract.

Compositional evolution of particle-phase reaction products and water in the heterogeneous OH oxidation of model aqueous organic aerosols

NASA Astrophysics Data System (ADS)

Chim, Man Mei; Cheng, Chiu Tung; Davies, James F.; Berkemeier, Thomas; Shiraiwa, Manabu; Zuend, Andreas; Nin Chan, Man

2017-12-01

Organic compounds present at or near the surface of aqueous droplets can be efficiently oxidized by gas-phase OH radicals, which alter the molecular distribution of the reaction products within the droplet. A change in aerosol composition affects the hygroscopicity and leads to a concomitant response in the equilibrium amount of particle-phase water. The variation in the aerosol water content affects the aerosol size and physicochemical properties, which in turn governs the oxidation kinetics and chemistry. To attain better knowledge of the compositional evolution of aqueous organic droplets during oxidation, this work investigates the heterogeneous OH-radical-initiated oxidation of aqueous methylsuccinic acid (C5H8O4) droplets, a model compound for small branched dicarboxylic acids found in atmospheric aerosols, at a high relative humidity of 85 % through experimental and modeling approaches. Aerosol mass spectra measured by a soft atmospheric pressure ionization source (Direct Analysis in Real Time, DART) coupled with a high-resolution mass spectrometer reveal two major products: a five carbon atom (C5) hydroxyl functionalization product (C5H8O5) and a C4 fragmentation product (C4H6O3). These two products likely originate from the formation and subsequent reactions (intermolecular hydrogen abstraction and carbon-carbon bond scission) of tertiary alkoxy radicals resulting from the OH abstraction occurring at the methyl-substituted carbon site. Based on the identification of the reaction products, a kinetic model of oxidation (a two-product model) coupled with the Aerosol Inorganic-Organic Mixtures Functional groups Activity Coefficients (AIOMFAC) model is built to simulate the size and compositional changes of aqueous methylsuccinic acid droplets during oxidation. Model results show that at the maximum OH exposure, the droplets become slightly more hygroscopic after oxidation, as the mass fraction of water is predicted to increase from 0.362 to 0.424; however, the diameter of the droplets decreases by 6.1 %. This can be attributed to the formation of volatile fragmentation products that partition to the gas phase, leading to a net loss of organic species and associated particle-phase water, and thus a smaller droplet size. Overall, fragmentation and volatilization processes play a larger role than the functionalization process in determining the evolution of aerosol water content and droplet size at high-oxidation stages.

POLONIUM SEPARATION PROCESS

DOEpatents

Karraker, D.G.

1959-07-14

A liquid-liquid extraction process is presented for the recovery of polonium from lead and bismuth. According to the invention an acidic aqueous chloride phase containing the polonium, lead, and bismuth values is contacted with a tributyl phosphate ether phase. The polonium preferentially enters the organic phase which is then separated and washed with an aqueous hydrochloric solution to remove any lead or bismuth which may also have been extracted. The now highly purified polonium in the organic phase may be transferred to an aqueous solution by extraction with aqueous nitric acid.

Microbial solubilization of phosphate

DOEpatents

Rogers, R.D.; Wolfram, J.H.

1993-10-26

A process is provided for solubilizing phosphate from phosphate containing ore by treatment with microorganisms which comprises forming an aqueous mixture of phosphate ore, microorganisms operable for solubilizing phosphate from the phosphate ore and maintaining the aqueous mixture for a period of time and under conditions operable to effect the microbial solubilization process. An aqueous solution containing soluble phosphorus can be separated from the reacted mixture by precipitation, solvent extraction, selective membrane, exchange resin or gravity methods to recover phosphate from the aqueous solution. 6 figures.

Microbial solubilization of phosphate

DOEpatents

Rogers, Robert D.; Wolfram, James H.

1993-01-01

A process is provided for solubilizing phosphate from phosphate containing ore by treatment with microorganisms which comprises forming an aqueous mixture of phosphate ore, microorganisms operable for solubilizing phosphate from the phosphate ore and maintaining the aqueous mixture for a period of time and under conditions operable to effect the microbial solubilization process. An aqueous solution containing soluble phosphorous can be separated from the reacted mixture by precipitation, solvent extraction, selective membrane, exchange resin or gravity methods to recover phosphate from the aqueous solution.

Process for preparing organoclays for aqueous and polar-organic systems

DOEpatents

Chaiko, David J.

2001-01-01

A process for preparing organoclays as thixotropic agents to control the rheology of water-based paints and other aqueous and polar-organic systems. The process relates to treating low-grade clay ores to achieve highly purified organoclays and/or to incorporate surface modifying agents onto the clay by adsorption and/or to produce highly dispersed organoclays without excessive grinding or high shear dispersion. The process involves the treatment of impure, or run-of-mine, clay using an aqueous biphasic extraction system to produce a highly dispersed clay, free of mineral impurities and with modified surface properties brought about by adsorption of the water-soluble polymers used in generating the aqueous biphasic extraction system. This invention purifies the clay to greater than 95%.

Siderophile-element Anomalies in CK Carbonaceous Chondrites: Implications for Parent-body Aqueous Alteration and Terrestrial Weathering of Sulfides

NASA Technical Reports Server (NTRS)

Huber, Heinz; Rubin, Alan E.; Kallemeyn, Gregory W.; Wasson, John T.

2006-01-01

CK chondrites constitute the most oxidized anhydrous carbonaceous chondrite group; most of the Fe occurs in magnetite and in FeO-rich mafic silicates. The two observed CK falls (Karoonda and Kobe), along with thirteen relatively unweathered CK finds, have unfractionated siderophile-element abundance patterns. In contrast, a sizable fraction of CK finds (9 of 24 investigated) shows fractionated siderophile abundance patterns including low abundances of Ni, Co, Se and Au; the most extreme depletions are in Ni (0.24 of normal CK) and Au (0.14 of normal CK). This depletion pattern has not been found in other chondrite groups. Out of the 74 CK chondrites listed in the Meteoritical Bulletin Database (2006; excluded considerably paired specimens; see http://tin.er.usgs.gov/meteor/ metbull.php) we analyzed 24 and subclassified the CK chondrites in terms of their chemical composition and sulfide mineralogy: sL (siderophiles low; six samples) for large depletions in Ni, Co, Se and Au (>50% of sulfides lost); sM (siderophiles medium; two CKs) for moderately low Ni and Co abundances (sulfides are highly altered or partly lost); sH (siderophiles high; one specimen) for enrichments in Ni, Co, Se and Au; 'normal' for unfractionated samples (13 samples). The sole sH sample may have obtained additional sulfide from impact redistribution in the parent asteroid. We infer that these elements became incorporated into sulfides after asteroidal aqueous processes oxidized nebular metal; thermal metamorphism probably also played a role in their mineral siting. The siderophile losses in the SL and sM samples are mainly the result of oxidation of pentlandite, pyrite and violarite by terrestrial alteration followed by leaching of the resulting phases. Some Antarctic CK chondrites have lost most of their sulfides but retained Ni, Co, Se and Au, presumably as insoluble weathering products.

Spitzer IRS Spectroscopy of the 10 Myr-Old EF Cha Debris Disk: Evidence for Phyllosilicate-Rich Dust in the Terrestrial Zone

NASA Technical Reports Server (NTRS)

Currie, Thayne; Lisse, Carey M.; Sicillia-Aguilar, Aurora; Rieke, George H.; Su, Kate Y. L.

2011-01-01

We describe Spitzer IRS spectroscopic observations of the approx. 10 Myr-old star, EF Chao Compositional modeling of the spectra from 5 micron to 35 micron confirms that it is surrounded by a luminous debris disk with L(sub D)/L(sub *) approx. 10(exp -3), containing dust with temperatures between 225 K and 430 K characteristic of the terrestrial zone. The EF Cha spectrum shows evidence for many solid-state features, unlike most cold, low-luminosity debris disks but like some other 10-20 Myr-old luminous, warm debris disks (e.g. HD 113766A). The EF Cha debris disk is unusually rich in a species or combination of species whose emissivities resemble that of finely-powdered, laboratory-measured phyllosilicate species (talc, saponite, and smectite), which are likely produced by aqueous alteration of primordial anhydrous rocky materials. The dust and, by inference, the parent bodies of the debris also contain abundant amorphous silicates and metal sulfides, and possibly water ice. The dust's total olivine to pyroxene ratio of approx. 2 also provides evidence of aqueous alteration. The large mass volume of grains with sizes comparable to or below the radiation blow-out limit implies that planetesimals may be colliding at a rate high enough to yield the emitting dust but not so high as to devolatize the planetesimals via impact processing. Because phyllosilicates are produced by the interactions between anhydrous rock and warm, reactive water, EF Cha's disk is a likely signpost for water delivery to the terrestrial zone of a young planetary system.

Experimental study of potential wellbore cement carbonation by various phases of carbon dioxide during geologic carbon sequestration

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

Jung, Hun Bok; Um, Wooyong

2013-08-16

Hydrated Portland cement was reacted with carbon dioxide (CO2) in supercritical, gaseous, and aqueous phases to understand the potential cement alteration processes along the length of a wellbore, extending from deep CO2 storage reservoir to the shallow subsurface during geologic carbon sequestration. The 3-D X-ray microtomography (XMT) images displayed that the cement alteration was significantly more extensive by CO2-saturated synthetic groundwater than dry or wet supercritical CO2 at high P (10 MPa)-T (50°C) conditions. Scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS) analysis also exhibited a systematic Ca depletion and C enrichment in cement matrix exposed to CO2-saturated groundwater. Integratedmore » XMT, XRD, and SEM-EDS analyses identified the formation of extensive carbonated zone filled with CaCO3(s), as well as the porous degradation front and the outermost silica-rich zone in cement after exposure to CO2-saturated groundwater. The cement alteration by CO2-saturated groundwater for 2-8 months overall decreased the porosity from 31% to 22% and the permeability by an order of magnitude. Cement alteration by dry or wet supercritical CO2 was slow and minor compared to CO2-saturated groundwater. A thin single carbonation zone was formed in cement after exposure to wet supercritical CO2 for 8 months or dry supercritical CO2 for 15 months. Extensive calcite coating was formed on the outside surface of a cement sample after exposure to wet gaseous CO2 for 1-3 months. The chemical-physical characterization of hydrated Portland cement after exposure to various phases of carbon dioxide indicates that the extent of cement carbonation can be significantly heterogeneous depending on CO2 phase present in the wellbore environment. Both experimental and geochemical modeling results suggest that wellbore cement exposure to supercritical, gaseous, and aqueous phases of CO2 during geologic carbon sequestration is unlikely to damage the wellbore integrity because cement alteration by all phases of CO2 is dominated by carbonation reaction. This is consistent with previous field studies of wellbore cement with extensive carbonation after exposure to CO2 for 3 decades. However, XMT imaging indicates that preferential cement alteration by supercritical CO2 or CO2-saturated groundwater can occur along the cement-steel or cement-rock interfaces. This highlights the importance of further investigation of cement degradation along the interfaces of wellbore materials to ensure permanent geologic carbon storage.« less

Fluid/rock Interaction History of a Faulted Rhyolite-Granite Contact Determined by Sr- Pb-Isotopes, Th/U-Disequilibria and Elemental Distributions (Eastern Rhine Graben Shoulder, SW-Germany)

NASA Astrophysics Data System (ADS)

Marbach, T.; Mangini, A.; Kober, B.; Schleicher, A.; Warr, L. N.

2003-04-01

Major and trace element analyses allow to obtain information concerning the chemical changes induced by alteration. Differences are partly petrographic because the profile crosses the granite-rhyolite contact, but they are also due to different alteration levels induced by fluid circulation along the fault system which has drained the alteration processes. The granite-rhyolite contact constitutes the primary structure. Only the most incompatible elements (Si, Al, Zr, Hf) retain their original signatures and reflect a mixing between typical granite and rhyolite lithologies across the altered zones (cataclasite). The more mobile elements show a different composition within the altered zones (cataclasite) notably a high leaching of cations. The geochemical tracers also suggest at least one strong hydrothermal event with reducing conditions in the altered zones. The isotopic analyses delivered qualitative and temporal information. The use of several isotopic systems, Rb/Sr-, U/Pb-isotopes and Th/U disequilibria, reveals a complex history of polyphase fluid/rock interaction following the Permian volcanic extrusion, showing notable disturbances during the late Jurassic hydrothermal activities, the Tertiary rifting of the Rhine Graben and more recent Quaternary alteration. The granite zone of the sampling profile has underwent an event which set up a new Rb-Sr isotopic composition and reset the Rb/Sr system which originatly corresponded to the Carboniferous intrusion ages. The Rb-Sr data of the granite samples produce a whole rock isochron of 152 ± 5,7 Ma (2σ error) in good agreement with the well-known late Jurassic hydrothermal event (135--160 Ma). The rocks evolution lines for Pb support a Tertiary hydrothermal event (54 Ma ± 16; 1σ error), potentially connected with the development of the Rhine Graben. The profile samples have undergone uranium and thorium redistribution processes which have occurred within the last ˜10^6 years. The samples of the altered zones record a more complex history of uranium exchange with the aqueous phase. This uranium exchange is proportional to the porosity. The best approximation is reached for an exchange coefficient (λ_E) for uranium ranging from 2,5 E-06 [a-1] in the middle of the altered zones to 2,5 E-05 [a-1] on the sides of the altered zones.

Variation of mineralogy and organic material during the early stages of aqueous activity recorded in Antarctic micrometeorites

NASA Astrophysics Data System (ADS)

Noguchi, T.; Yabuta, H.; Itoh, S.; Sakamoto, N.; Mitsunari, T.; Okubo, A.; Okazaki, R.; Nakamura, T.; Tachibana, S.; Terada, K.; Ebihara, M.; Imae, N.; Kimura, M.; Nagahara, H.

2017-07-01

Micrometeorites (MMs) recovered from surface snow near the Dome Fuji Station, Antarctica are almost free from terrestrial weathering and contain very primitive materials, and are suitable for investigation of the evolution and interaction of inorganic and organic materials in the early solar system. We carried out a comprehensive study on seven porous and fluffy MMs [four Chondritic porous (CP) MMs and three fluffy fine-grained (Fluffy Fg) MMs] and one fine-grained type 1 (Fg C1) MM for comparison with scanning electron microscope, transmission electron microscope, X-ray absorption near-edge structure analysis, and secondary ion mass spectrometer. They show a variety of early aqueous activities. Four out of the seven CP MMs contain glass with embedded metal and sulfide (GEMS) and enstatite whiskers/platelets and do not have hydrated minerals. Despite the same mineralogy, organic chemistry of the CP MMs shows diversity. Two of them contain considerable amounts of organic materials with high carboxyl functionality, and one of them contains nitrile (Ctbnd N) and/or nitrogen heterocyclic groups with D and 15N enrichments, suggesting formation in the molecular cloud or a very low temperature region of the outer solar system. Another two CP MMs are poorer in organic materials than the above-mentioned MMs. Organic material in one of them is richer in aromatic C than the CP MMs mentioned above, being indistinguishable from those of hydrated carbonaceous chondrites. In addition, bulk chemical compositions of GEMS in the latter organic poor CP MMs are more homogeneous and have higher Fe/(Si + Mg + Fe) ratios than those of GEMS in the former organic-rich CP MMs. Functional group of the organic materials and amorphous silicate in GEMS in the organic-poor CP MMs may have transformed in the earliest stage of aqueous alteration, which did not form hydrated minerals. Three Fluffy Fg MMs contain abundant phyllosilicates, showing a clear evidence of aqueous alteration. Phyllosilicates in thee MMs are richer in Fe than those in hydrated IDPs, typical fine-grained hydrated (Fg C1) MMs, and hydrated carbonaceous chondrites. One of the Fluffy Fg MMs contains amorphous silicate, which is richer in Fe than GEMS and contains little or no nanophase Fe metal but contains Fe sulfide. Because the chemical compositions of the amorphous silicate are within the compositional field of GEMS in CP IDPs, the amorphous silicate may be alteration products of GEMS. The entire compositional field of GEMS in the CP MMs and the amorphous silicate in the Fluffy Fg MM matches that of the previously reported total compositional range of GEMS in IDPs. One Fluffy Fg MM contains Mg-rich phyllosilicate along with Fe-rich phyllosilicate and Mg-Fe carbonate. Mg-rich phyllosilicate and Mg-Fe carbonate may have been formed through the reaction of Fe-rich phyllosilicate, Mg-rich olivine and pyroxene, and water with C-bearing chemical species. These data indicate that CP MMs and Fluffy Fg MMs recovered from Antarctic surface snow contain materials that throw a light on the earliest stages of aqueous alteration on very primitive solar system bodies. Because mineralogy and isotopic and structural features of organic materials in D10IB009 are comparable with isotopically primitive IDPs, its parent body could be comets or icy asteroids showing mass ejection (active asteroids). By contrast, organic-poor CP MMs may have experienced the earliest stage of aqueous alteration and Fluffy Fg MMs experienced weak aqueous alteration. The precursor materials of the parent bodies of Fluffy Fg MMs probably contained abundant GEMS or GEMS-like materials like CP IDPs, which is common to fine-grained matrices of very primitive carbonaceous chondrites such as CR3s. However, highly porous nature of organic-poor CP MMs and Fluffy Fg MMs suggests that parent bodies of these MMs must have been much more porous than the parent bodies of primitive carbonaceous chondrites. Given no phyllosilicate among the returned samples of 81P/Wild 2 comet, the MMs may have been derived from porous icy asteroids such as active asteroids as well as P- and D-type asteroids rather than comets.

Formation of an active dimer during storage of interleukin-1 receptor antagonist in aqueous solution.

PubMed Central

Chang, B S; Beauvais, R M; Arakawa, T; Narhi, L O; Dong, A; Aparisio, D I; Carpenter, J F

1996-01-01

The degradation products of recombinant human interleukin-1 receptor antagonist (rhIL-1ra) formed during storage at 30 degrees C in aqueous solution were characterized. Cationic exchange chromatography of the stored sample showed two major, new peaks eluting before (P1) and after (L2) the native protein, which were interconvertible. Size-exclusion chromatography and electrophoresis documented that both the P1 and L2 fractions were irreversible dimers, formed by noncovalent interactions. A competition assay with interleukin-1 indicated that on a per monomer basis the P1 and L2 dimers retained about two-thirds of the activity of the native monomer. Infrared and far-UV circular dichroism spectroscopies showed that only minor alterations in secondary structure arose upon the formation of the P1 dimer. However, alteration in the near-UV circular dichroism spectrum suggested the presence of disulfide bonds in the P1 dimer, which are absent in the native protein. Mass spectroscopy and tryptic mapping, before and after carboxymethylation, demonstrated that the P1 dimer contained an intramolecular disulfide bond between Cys-66 and Cys-69. Although conversion of native protein to the P1 dimer was irreversible in buffer alone, the native monomer could be regained by denaturing the P1 dimer with guanidine hydrochloride and renaturing it by dialysis, suggesting that the intramolecular disulfide bond does not interfere with refolding. Analysis of the time course of P1 formation during storage at 30 degrees C indicated that the process followed first-order, and not second-order, kinetics, suggesting that the rate-limiting step was not dimerization. It is proposed that a conformational change in the monomer is the rate-limiting step in the formation of the P1 dimer degradation product. Sucrose stabilized the native monomer against this process. This result can be explained by the general stabilization mechanism for this additive, which is due to its preferential exclusion from the protein surface. PMID:8968609

Altered Antioxidant-Oxidant Status in the Aqueous Humor and Peripheral Blood of Patients with Retinitis Pigmentosa

PubMed Central

Martínez-Fernández de la Cámara, Cristina; Salom, David; Sequedo, Ma Dolores; Hervás, David; Marín-Lambíes, Cristina; Aller, Elena; Jaijo, Teresa; Díaz-LLopis, Manuel; Millán, José María; Rodrigo, Regina

2013-01-01

Retinitis Pigmentosa is a common form of hereditary retinal degeneration constituting the largest Mendelian genetic cause of blindness in the developed world. It has been widely suggested that oxidative stress possibly contributes to its pathogenesis. We measured the levels of total antioxidant capacity, free nitrotyrosine, thiobarbituric acid reactive substances (TBARS) formation, extracellular superoxide dismutase (SOD3) activity, protein, metabolites of the nitric oxide/cyclic GMP pathway, heme oxygenase-I and inducible nitric oxide synthase expression in aqueous humor or/and peripheral blood from fifty-six patients with retinitis pigmentosa and sixty subjects without systemic or ocular oxidative stress-related disease. Multivariate analysis of covariance revealed that retinitis pigmentosa alters ocular antioxidant defence machinery and the redox status in blood. Patients with retinitis pigmentosa present low total antioxidant capacity including reduced SOD3 activity and protein concentration in aqueous humor. Patients also show reduced SOD3 activity, increased TBARS formation and upregulation of the nitric oxide/cyclic GMP pathway in peripheral blood. Together these findings confirmed the hypothesis that patients with retinitis pigmentosa present reduced ocular antioxidant status. Moreover, these patients show changes in some oxidative-nitrosative markers in the peripheral blood. Further studies are needed to clarify the relationship between these peripheral markers and retinitis pigmentosa. PMID:24069283

The formation environment of potassic-chloro-hastingsite in the nakhlites MIL 03346 and pairs and NWA 5790: Insights from terrestrial chloro-amphibole

NASA Astrophysics Data System (ADS)

Giesting, Paul A.; Filiberto, Justin

2016-11-01

Potassic-chloro-hastingsite has been found in melt inclusions in MIL 03346, its paired stones, and NWA 5790. It is some of the most chlorine-rich amphibole ever analyzed. In this article, we evaluate what crystal chemistry, terrestrial analogs, and experiments have shown about how chlorine-dominant amphibole (chloro-amphibole) forms and apply these insights to the nakhlites. Chloro-amphibole is rare, with about a dozen identified localities on Earth. It is always rich in potassium and iron and poor in titanium. In terrestrial settings, its presence has been interpreted to result from medium to high-grade alteration (>400 °C) of a protolith by an alkali and/or iron chloride-rich aqueous fluid. Ferrous chloride fluids exsolved from mafic magmas can cause such alteration, as can crustal fluids that have reacted with rock and lost H2O in preference to chloride, resulting in concentrated alkali chloride fluids. In the case of the nakhlites, an aqueous alkali-ferrous chloride fluid was exsolved from the parental melt as it crystallized. This aqueous chloride fluid itself likely unmixed into chloride-dominant and water-dominant fluids. Chloride-dominant fluid was trapped in some melt inclusions and reacted with the silicate contents of the inclusion to form potassic-chloro-hastingsite.

Expanded polytetrafluoroethylene membrane alters tissue response to implanted Ahmed glaucoma valve.

PubMed

DeCroos, Francis Char; Ahmad, Sameer; Kondo, Yuji; Chow, Jessica; Mordes, Daniel; Lee, Maria Regina; Asrani, Sanjay; Allingham, R Rand; Olbrich, Kevin C; Klitzman, Bruce

2009-07-01

Long-term intraocular pressure control by glaucoma drainage implants is compromised by the formation of an avascular fibrous capsule that surrounds the glaucoma implant and increases aqueous outflow resistance. It is possible to alter this fibrotic tissue reaction and produce a more vascularized and potentially more permeable capsule around implanted devices by enclosing them in a porous membrane. Ahmed glaucoma implants modified with an outer 5-microm pore size membrane (termed porous retrofitted implant with modified enclosure or PRIME-Ahmed) and unmodified glaucoma implants were implanted into paired rabbit eyes. After 6 weeks, the devices were explanted and subject to histological analysis. A tissue response containing minimal vascularization, negligible immune response, and a thick fibrous capsule surrounded the unmodified Ahmed glaucoma implant. In comparison, the tissue response around the PRIME-Ahmed demonstrated a thinner fibrous capsule (46.4 +/- 10.8 microm for PRIME-Ahmed versus 94.9 +/- 21.2 microm for control, p < 0.001) and was highly vascularized near the tissue-material interface. A prominent chronic inflammatory response was noted as well. Encapsulating the aqueous outflow pathway with a porous membrane produces a more vascular tissue response and thinner fibrous capsule compared with a standard glaucoma implant plate. Enhanced vascularity and a thinner fibrous capsule may reduce aqueous outflow resistance and improve long-term glaucoma implant performance.

Low-Resolution Spectroscopy of Primitive Asteroids: Progress Report for SARA/VSU Survey

NASA Technical Reports Server (NTRS)

Leake, M. A.; Nogues, J. P.; Gaines, J. K.; Looper, J. K.; Freitas, K. A.

2001-01-01

Progress on a low-resolution survey of primitive C-class asteroids continues using new equipment (and its associated problems) to understand aqueous alteration in the solar system. Additional information is contained in the original extended abstract.

Composition and process for separating cesium ions from an acidic aqueous solution also containing other ions

DOEpatents

Dietz, Mark L.; Horwitz, E. Philip; Bartsch, Richard A.; Barrans, Jr., Richard E.; Rausch, David

1999-01-01

A crown ether cesium ion extractant is disclosed as is its synthesis. The crown ether cesium ion extractant is useful for the selective purification of cesium ions from aqueous acidic media, and more particularly useful for the isolation of radioactive cesium-137 from nuclear waste streams. Processes for isolating cesium ions from aqueous acidic media using the crown ether cesium extractant are disclosed as are processes for recycling the crown ether cesium extractant and processes for recovering cesium from a crown ether cesium extractant solution.

Composition and process for separating cesium ions from an acidic aqueous solution also containing other ions

DOEpatents

Dietz, M.L.; Horwitz, E.P.; Bartsch, R.A.; Barrans, R.E. Jr.; Rausch, D.

1999-03-30

A crown ether cesium ion extractant is disclosed as is its synthesis. The crown ether cesium ion extractant is useful for the selective purification of cesium ions from aqueous acidic media, and more particularly useful for the isolation of radioactive cesium-137 from nuclear waste streams. Processes for isolating cesium ions from aqueous acidic media using the crown ether cesium extractant are disclosed as are processes for recycling the crown ether cesium extractant and processes for recovering cesium from a crown ether cesium extractant solution. 4 figs.

Aqueous Alteration of the Grosnaja CV3 Carbonaceous Chondrite

NASA Astrophysics Data System (ADS)

Keller, L. P.; McKay, D. S.

1993-07-01

Previous petrographic studies have shown that aqueous alteration products are locally well developed in some of the CV3 falls [e.g., 1-3]. In this abstract, we describe our transmission electron microscope (TEM) study of the extent of aqueous alteration in matrix and in chondrules in the Grosnaja CV3 carbonaceous chondrite. Grosnaja is an observed fall and belongs to the oxidized subgroup of the CV chondrites [4]. We obtained fragments of Grosnaja from the Naturhistorisches Museum in Vienna. Regions of interest were extracted from polished thin sections and prepared for TEM observation by ion milling. Quantitative energy-dispersive X-ray (EDX) analyses were obtained using a JEOL 2000FX TEM equipped with a LINK thin- window EDX detector. Grosnaja has undergone aqueous alteration, which has resulted in the formation of phyllosilicates in matrix and in chondrules. The suprising result from Grosnaja is that three different types of phyllosilicates are intimately intergrown. Serpentine is the most abundant phyllosilicate in matrix and occurs as fine-grained packets along grain boundaries and as fracture-fillings and veinlets that cross cut olivine and pyroxene grains. Mixed with the serpentine are packets of fine-grained phyllosilicates with a distinct 1.4-nm basal spacing that is probably a chlorite group mineral. Rare packets of smectite occur as epitaxial intergrowths with olivine, but are not interstratified with serpentine as observed in the CI chondrites. Phyllosilicates in Grosnaja matrix occur with Mg-rich carbonates, fine-grained magnetite, chromite and pentlandite, and poorly-crystalline FeNi- oxide/hydroxides, which stain the matrix a brownish-red color. Some of the rust may be of terrestrial origin (Grosnaja fell in 1861). Although the matrix phyllosilicates are too small to obtain single-phase chemical analyses in the TEM, quantitative EDX analyses suggest that the serpentine contains significant Fe (Mg/Mg + Fe ~0.5). The serpentine/chlorite forms as an alteration product of matrix olivine. Olivine in matrix is equilibrated (Fa(sub)50). The matrix olivines contain numerous planar defects along (100) planes, which results in strong streaking along a* in electron diffraction patterns. These planar defects in matrix olivines are common in other CV chondrites, including Bali [3] and Mokoia [1]. Chondrule mesostasis is extensively altered to coarse-grained Na-saponite that is coherently interstratified with a 1.4-nm phyllosilicate (as shown by selected-area electron diffraction patterns). The 1.4-nm layers occur individually and in groups up to five layers wide. Serpentine has not been observed in chondrules. The Mg/Mg + Fe (atomic) ratio for the saponite is ~0.9, the same as for the host chondrule olivines. The formation of phyllosilicates in Grosnaja was controlled by local bulk compositions. The abundance of Na and Al in chondrule mesostasis stabilized Na-saponite, while in matrix, the high olivine content resulted in formation of serpentine. Grosnaja is unusual for a CV chondrite in that the dominant phyllosilicates in matrix are serpentine and chlorite, whereas smectite is the dominant phyllosilicate for the other altered CV chondrites [3]. This result suggests that alteration conditions were different for Grosnaja relative to the other CV falls. We believe that the occurrence of chlorite in both matrix and chondrules indicates alteration at temperatures higher than those experienced by the other altered CV chondrites. The heat source for the alteration reactions may be related to the thermal event that equilibrated matrix olivines. Acknowledgements: We thank G. Kurat of the Naturhistorisches Museum for samples of Grosnaja. This work was supported by NASA RTOPs 152-17-40-23 and 199-52-11-02. References: [1] Tomeoka K. and Buseck P. R. (1990) GCA, 54, 1745. [2] Keller L. P. and Buseck P. R. (1990) GCA, 54, 2113. [3] Keller L. P. and Thomas K. L. (1991) LPS XXII, 705. [4] McSween H. Y. (1977) GCA, 41, 1777.

Behavior of Paramecium sp. in solutions containing Sr and Pb: Do Paramecium sp. alter chemical forms of those metals?

NASA Astrophysics Data System (ADS)

Kozai, Naofumi; Ohnuki, Toshihiko; Koka, Masahi; Satoh, Takahiro; Kamiya, Tomihiro

2011-10-01

The behavior of Paramecium sp. (Paramecium bursaria) in aqueous solutions containing Sr and Pb was investigated to determine the role of protozoa in the migration of radionuclides in the environment. Precultured living cells of P. bursaria were exposed to aqueous solutions containing 0.01 or 0.05 mM Sr or Pb at pH 7 for 24 h. For comparison, pre-killed cells were treated with the metal solutions in the same way. Two-dimensional elemental mappings of cells were obtained by micro-PIXE. Aquatic species of Sr and Pb were analyzed by size exclusion chromatography (SEC) coupled online to ultraviolet (UV) spectroscopy and inductivity coupled plasma mass spectroscopy (ICP-MS). The amounts of Sr adsorbed or taken up by the cells surviving for 24 h and adsorbed on pre-killed cells were below the detection limit. Cells of P. bursaria adsorbed or took up a fraction of Pb. The Pb adsorbed or taken up by the cells surviving for 24 h in the Pb solution was barely detectable, while the Pb adsorbed on pre-killed cells was clearly mappable. These findings suggest that living cells of P. bursaria have functions that reduce adsorption or uptake of Pb on the cells. Quantitative and SEC-UV-ICP-MS analyses of the Sr and Pb in aqueous phases showed no clear evidences that living cells of P. bursaria alter the chemical form of Sr or Pb remaining in the aqueous phases after the cell-solution contact.

Abiotic Organic Chemistry in Hydrothermal Systems.

NASA Astrophysics Data System (ADS)

Simoneit, B. R.; Rushdi, A. I.

2004-12-01

Abiotic organic chemistry in hydrothermal systems is of interest to biologists, geochemists and oceanographers. This chemistry consists of thermal alteration of organic matter and minor prebiotic synthesis of organic compounds. Thermal alteration has been extensively documented to yield petroleum and heavy bitumen products from contemporary organic detritus. Carbon dioxide, carbon monoxide, ammonia and sulfur species have been used as precursors in prebiotic synthesis experiments to organic compounds. These inorganic species are common components of hot spring gases and marine hydrothermal systems. It is of interest to further test their reactivities in reductive aqueous thermolysis. We have synthesized organic compounds (lipids) in aqueous solutions of oxalic acid, and with carbon disulfide or ammonium bicarbonate at temperatures from 175-400° C. The synthetic lipids from oxalic acid solutions consisted of n-alkanols, n-alkanoic acids, n-alkyl formates, n-alkanones, n-alkenes and n-alkanes, typically to C30 with no carbon number preferences. The products from CS2 in acidic aqueous solutions yielded cyclic thioalkanes, alkyl polysulfides, and thioesters with other numerous minor compounds. The synthesis products from oxalic acid and ammonium bicarbonate solutions were homologous series of n-alkyl amides, n-alkyl amines, n-alkanes and n-alkanoic acids, also to C30 with no carbon number predominance. Condensation (dehydration) reactions also occur under elevated temperatures in aqueous medium as tested by model reactions to form amide, ester and nitrile bonds. It is concluded that the abiotic formation of aliphatic lipids, condensation products (amides, esters, nitriles, and CS2 derivatives (alkyl polysulfides, cyclic polysulfides) is possible under hydrothermal conditions and warrants further studies.

Method for separating water soluble organics from a process stream by aqueous biphasic extraction

DOEpatents

Chaiko, David J.; Mego, William A.

1999-01-01

A method for separating water-miscible organic species from a process stream by aqueous biphasic extraction is provided. An aqueous biphase system is generated by contacting a process stream comprised of water, salt, and organic species with an aqueous polymer solution. The organic species transfer from the salt-rich phase to the polymer-rich phase, and the phases are separated. Next, the polymer is recovered from the loaded polymer phase by selectively extracting the polymer into an organic phase at an elevated temperature, while the organic species remain in a substantially salt-free aqueous solution. Alternatively, the polymer is recovered from the loaded polymer by a temperature induced phase separation (cloud point extraction), whereby the polymer and the organic species separate into two distinct solutions. The method for separating water-miscible organic species is applicable to the treatment of industrial wastewater streams, including the extraction and recovery of complexed metal ions from salt solutions, organic contaminants from mineral processing streams, and colorants from spent dye baths.

Aqueous and Ethanolic Valeriana officinalis Extracts Change the Binding of Ligands to Glutamate Receptors

PubMed Central

Del Valle-Mojica, Lisa M.; Cordero-Hernández, José M.; González-Medina, Giselle; Ramos-Vélez, Igmeris; Berríos-Cartagena, Nairimer; Torres-Hernández, Bianca A.; Ortíz, José G.

2011-01-01

The effects of two valerian extracts (aqueous and hydroalcoholic) were investigated through [3H]Glutamate ([3H]Glu) and [3H]Fluorowillardine ([3H]FW) receptor binding assays using rat synaptic membranes in presence of different receptor ligands. In addition, the extract stability was monitored spectrophotometrically. Both extracts demonstrated interaction with ionotropic glutamate receptors (iGluRs). However, the extracts displayed considerable differences in receptor selectivity. The hydroalcoholic extract selectively interacted with quisqualic acid (QA), group I metabotropic glutamate receptor (mGluR) ligand, while the aqueous extract did not alter the binding of QA. The stability of the extracts was examined during several weeks. Freshly prepared extract inhibited 38–60% of [3H]FW binding (AMPA). After 10 days, the aqueous extract inhibited 85% of [3H]FW binding while the hydroalcoholic extract markedly potentiated (200%) [3H]FW binding to AMPA receptors. Thus, our results showed that factors such as extraction solvent and extract stability determine the selectivity for glutamate receptor (GluR) interactions. PMID:21151614

Aqueous and Ethanolic Valeriana officinalis Extracts Change the Binding of Ligands to Glutamate Receptors.

PubMed

Del Valle-Mojica, Lisa M; Cordero-Hernández, José M; González-Medina, Giselle; Ramos-Vélez, Igmeris; Berríos-Cartagena, Nairimer; Torres-Hernández, Bianca A; Ortíz, José G

2011-01-01

The effects of two valerian extracts (aqueous and hydroalcoholic) were investigated through [(3)H]Glutamate ([(3)H]Glu) and [(3)H]Fluorowillardine ([(3)H]FW) receptor binding assays using rat synaptic membranes in presence of different receptor ligands. In addition, the extract stability was monitored spectrophotometrically. Both extracts demonstrated interaction with ionotropic glutamate receptors (iGluRs). However, the extracts displayed considerable differences in receptor selectivity. The hydroalcoholic extract selectively interacted with quisqualic acid (QA), group I metabotropic glutamate receptor (mGluR) ligand, while the aqueous extract did not alter the binding of QA. The stability of the extracts was examined during several weeks. Freshly prepared extract inhibited 38-60% of [(3)H]FW binding (AMPA). After 10 days, the aqueous extract inhibited 85% of [(3)H]FW binding while the hydroalcoholic extract markedly potentiated (200%) [(3)H]FW binding to AMPA receptors. Thus, our results showed that factors such as extraction solvent and extract stability determine the selectivity for glutamate receptor (GluR) interactions.

Petrographic and C & O isotopic characteristics of the earliest stages of aqueous alteration of CM chondrites

NASA Astrophysics Data System (ADS)

Vacher, Lionel G.; Marrocchi, Yves; Villeneuve, Johan; Verdier-Paoletti, Maximilien J.; Gounelle, Matthieu

2017-09-01

CM chondrites form the largest group of hydrated meteorites and span a wide range of alteration states, with the Paris meteorite being the least altered CM described to date. Ca-Carbonates are powerful proxies for the alteration conditions of CMs because they are direct snapshots of the chemical and isotopic compositions of the parent fluids. Here, we report a petrographic and a C isotope and O isotope survey of Ca-carbonates in Paris in order to better characterize the earliest stages of aqueous alteration. Petrographic observations show that Paris contains two distinct populations of Ca-carbonates: Type 1a Ca-carbonates, which are surrounded by rims of tochilinite/cronstedtite intergrowths (TCIs), and new Type 0 Ca-carbonates, which do not exhibit the TCI rims. The TCI rims of Type 1a Ca-carbonates commonly outline euhedral crystal faces, demonstrating that these Ca-carbonates were (i) partially or totally pseudomorphosed by TCI and (ii) precipitated at the earliest stages of aqueous alteration, before Type 0 Ca-carbonates. Isotopic measurements show that Paris' Ca-carbonates have δ13C values that range from 19 to 80‰ (PDB), δ18O values that range from 29 to 41%, and δ17O values that range from 13 to 24‰ (SMOW). According to the δ13C-δ18O values of Paris' Ca-carbonates, we developed a new alteration model that involves (i) the equilibration of a primordial 17,18O-rich water (PW) with 16O-rich anhydrous silicates and (ii) varying contribution of 12C- and 13C-rich soluble organic matter (SOMs). It also suggests that many parameters control the C and O isotopic composition of Ca-carbonates, the principles being the degree of isotopic equilibration between the PW and the anhydrous silicates, the respective contribution of 12C and 13C-rich SOMs as well as the thermal evolution of CM parent bodies. Consequently, we suggest that CM Ca-carbonates could record both positive and negative δ13C-δ18O relationships, but a systematic correspondence is probably absent in CM chondrites due to the large number of factors involved in generating the isotopic characteristics of Ca-carbonates. From recent reports of the C-isotopic compositions of SOM in CM chondrites, we propose that water-soluble organic compounds were the most probable source of 13C enrichment in the majority of CM carbonates.

Mineralogy and stratigraphy of phyllosilicate-bearing and dark mantling units in the greater Mawrth Vallis/west Arabia Terra area: Constraints on geological origin

USGS Publications Warehouse

Noe Dobrea, E.Z.; Bishop, J.L.; McKeown, N.K.; Fu, R.; Rossi, C.M.; Michalski, J.R.; Heinlein, C.; Hanus, V.; Poulet, F.; Mustard, R.J.F.; Murchie, S.; McEwen, A.S.; Swayze, G.; Bibring, J.-P.; Malaret, E.; Hash, C.

2010-01-01

Analyses of MRO/CRISM images of the greater Mawrth Vallis region of Mars affirm the presence of two primary phyllosilicate assemblages throughout a region ∼1000 × 1000 km. These two units consist of an Fe/Mg-phyllosilicate assemblage overlain by an Al-phyllosilicate and hydrated silica assemblage. The lower unit contains Fe/Mg-smectites, sometimes combined with one or more of these other Fe/Mg-phyllosilicates: serpentine, chlorite, biotite, and/or vermiculite. It is more than 100 m thick and finely layered at meter scales. The upper unit includes Al-smectite, kaolin group minerals, and hydrated silica. It is tens of meters thick and finely layered as well. A common phyllosilicate stratigraphy and morphology is observed throughout the greater region wherever erosional windows are present. This suggests that the geologic processes forming these units must have occurred on at least a regional scale. Sinuous ridges (interpreted to be inverted channels) and narrow channels cut into the upper clay-bearing unit suggesting that aqueous processes were prevalent after, and possibly during, the deposition of the layered units. We propose that layered units may have been deposited at Mawrth Vallis and then subsequently altered to form the hydrated units. The Fe/Mg-phyllosilicate assemblage is consistent with hydrothermal alteration or pedogenesis of mafic to ultramafic rocks. The Al-phyllosilicate/hydrated silica unit may have formed through alteration of felsic material or via leaching of basaltic material through pedogenic alteration or a mildly acidic environment. These phyllosilicate-bearing units are overlain by a darker, relatively unaltered, and indurated material that has probably experienced a complex geological history.

Visualizing different uranium oxidation states during the surface alteration of uraninite and uranium tetrachloride.

PubMed

Grossmann, Kay; Arnold, Thuro; Steudtner, Robin; Weiss, Stefan; Bernhard, Gert

2009-08-01

Low-temperature alteration reactions on uranium phases may lead to the mobilization of uranium and thereby poses a potential threat to humans living close to uranium-contaminated sites. In this study, the surface alteration of uraninite (UO(2)) and uranium tetrachloride (UCl(4)) in air atmosphere was studied by confocal laser scanning microscopy (CLSM) and laser-induced fluorescence spectroscopy using an excitation wavelength of 408 nm. It was found that within minutes the oxidation state on the surface of the uraninite and the uranium tetrachloride changed. During the surface alteration process U(IV) atoms on the uraninite and uranium tetrachloride surface became stepwise oxidized by a one-electron step at first to U(V) and then further to U(VI). These observed changes in the oxidation states of the uraninite surface were microscopically visualized and spectroscopically identified on the basis of their fluorescence emission signal. A fluorescence signal in the wavelength range of 415-475 nm was indicative for metastable uranium(V), and a fluorescence signal in the range of 480-560 nm was identified as uranium(VI). In addition, the oxidation process of tetravalent uranium in aqueous solution at pH 0.3 was visualized by CLSM and U(V) was fluorescence spectroscopically identified. The combination of microscopy and fluorescence spectroscopy provided a very convincing visualization of the brief presence of U(V) as a metastable reaction intermediate and of the simultaneous coexistence of the three states U(IV), U(V), and U(VI). These results have a significant importance for fundamental uranium redox chemistry and should contribute to a better understanding of the geochemical behavior of uranium in nature.

Thermal Infrared Emission Spectroscopy of Synthetic Allophane and its Potential Formation on Mars

NASA Technical Reports Server (NTRS)

Rampe, E. B.; Kraft, M. D.; Sharp, T. G.; Golden, D. C.; Ming, Douglas W.

2010-01-01

Allophane is a poorly-crystalline, hydrous aluminosilicate with variable Si/Al ratios approx.0.5-1 and a metastable precursor of clay minerals. On Earth, it forms rapidly by aqueous alteration of volcanic glass under neutral to slightly acidic conditions [1]. Based on in situ chemical measurements and the identification of alteration phases [2-4], the Martian surface is interpreted to have been chemically weathered on local to regional scales. Chemical models of altered surfaces detected by the Mars Exploration Rover Spirit in Gusev crater suggest the presence of an allophane-like alteration product [3]. Thermal infrared (TIR) spectroscopy and spectral deconvolution models are primary tools for determining the mineralogy of the Martian surface [5]. Spectral models of data from the Thermal Emission Spectrometer (TES) indicate a global compositional dichotomy, where high latitudes tend to be enriched in a high-silica material [6,7], interpreted as high-silica, K-rich volcanic glass [6,8]. However, later interpretations proposed that the high-silica material may be an alteration product (such as amorphous silica, clay minerals, or allophane) and that high latitude surfaces are chemically weathered [9-11]. A TIR spectral library of pure minerals is available for the public [12], but it does not contain allophane spectra. The identification of allophane on the Martian surface would indicate high water activity at the time of its formation and would help constrain the aqueous alteration environment [13,14]. The addition of allophane to the spectral library is necessary to address the global compositional dichotomy. In this study, we characterize a synthetic allophane by IR spectroscopy, X-ray diffraction (XRD), and transmission electron microscopy (TEM) to create an IR emission spectrum of pure allophane for the Mars science community to use in Martian spectral models.

The role of surface chemical analysis in a study to select replacement processes for TCA vapor degreasing

NASA Technical Reports Server (NTRS)

Lesley, Michael W.; Davis, Lawrence E.; Moulder, John F.; Carlson, Brad A.

1995-01-01

The role of surface-sensitive chemical analysis (ESCA, AES, and SIMS) in a study to select a process to replace 1, 1, 1-trichloroethane (TCA) vapor degreasing as a steel and aluminum bonding surface preparation method is described. The effort was primarily concerned with spray-in-air cleaning processes involving aqueous alkaline and semi-aqueous cleaners and a contamination sensitive epoxy-to-metal bondline. While all five cleaners tested produced bonding strength results equal to or better than those produced by vapor degreasing, the aqueous alkaline cleaners yielded results which were superior to those produced by the semi-aqueous cleaners. The main reason for the enhanced performance appears to be a silicate layer left behind by the aqueous alkaline cleaners. The silicate layer increases the polarity of the surface and enhances epoxy-to-metal bonding. On the other hand, one of the semi-aqueous cleaners left a nonpolar carbonaceous residue which appeared to have a negative effect on epoxy-to-metal bonding. Differences in cleaning efficiency between cleaners/processes were also identified. These differences in surface chemistry, which were sufficient to affect bonding, were not detected by conventional chemical analysis techniques.

Insights Into Atmospheric Aqueous Organic Chemistry Through Controlled Experiments with Cloud Water Surrogates

NASA Astrophysics Data System (ADS)

Turpin, B. J.; Ramos, A.; Kirkland, J. R.; Lim, Y. B.; Seitzinger, S.

2011-12-01

There is considerable laboratory and field-based evidence that chemical processing in clouds and wet aerosols alters organic composition and contributes to the formation of secondary organic aerosol (SOA). Single-compound laboratory experiments have played an important role in developing aqueous-phase chemical mechanisms that aid prediction of SOA formation through multiphase chemistry. In this work we conduct similar experiments with cloud/fog water surrogates, to 1) evaluate to what extent the previously studied chemistry is observed in these more realistic atmospheric waters, and 2) to identify additional atmospherically-relevant precursors and products that require further study. We used filtered Camden and Pinelands, NJ rainwater as a surrogate for cloud water. OH radical (~10-12 M) was formed by photolysis of hydrogen peroxide and samples were analyzed in real-time by electrospray ionization mass spectroscopy (ESI-MS). Discrete samples were also analyzed by ion chromatography (IC) and ESI-MS after IC separation. All experiments were performed in duplicate. Standards of glyoxal, methylglyoxal and glycolaldehyde and their major aqueous oxidation products were also analyzed, and control experiments performed. Decreases in the ion abundance of many positive mode compounds and increases in the ion abundance of many negative mode compounds (e.g., organic acids) suggest that precursors are predominantly aldehydes, organic peroxides and/or alcohols. Real-time ESI mass spectra were consistent with the expected loss of methylglyoxal and subsequent formation of pyruvate, glyoxylate, and oxalate. New insights regarding other potential precursors and products will be provided.

Habitability Conditions Constrained by Martian Meteorites: Implications for Microbial Colonization and Mars Sample Return

NASA Astrophysics Data System (ADS)

Shivak, J. N.; Banerjee, N.; Flemming, R. L.

2013-12-01

We report the results of a comparative study of the crustal environmental conditions recorded by several Martian meteorites (Nakhla, Los Angeles, and Zagami). Though no samples have yet been returned from Mars, numerous meteorites are known and these provide the only samples of the Martian crust currently available for study. Terrestrial basalts and other mafic igneous rocks are analogous in many ways to much of the Martian crust, as evidenced by the composition of known Martian meteorites and measurements from planetary missions [1]. Microorganisms are known to thrive in the terrestrial geosphere and make use of many different substrates within rock in the subsurface of the Earth [2]. The action of aqueous solutions in the Martian crust has been well established through the study of alteration mineral assemblages present in many Martian meteorites, such as the nakhlites [3]. Aqueous activity in terrestrial chemolithoautotrophic habitats provides numerous energy and nutrient sources for microbes [4], suggesting the potential for habitable endolithic environments in Martian rocks. Fayalite in Nakhla has experienced extensive aqueous alteration to reddish-brown 'iddingsite' material within a pervasive fracture system. Textural imaging shows the replacement of primary olivine with various alteration phases and infiltration of this alteration front into host grains. Geochemical analysis of the alteration material shows the addition of iron and silica and removal of magnesium during alteration. Novel In situ Micro-XRD and Raman Spectroscopy of this material reveals a new assemblage consisting of iron oxides, smectite clays, carbonates, and a minor serpentine component. The alteration mineral assemblage here differs from several that have been previously reported [4] [5], allowing for a reevaluation of the environmental conditions during fluid action. Los Angeles and Zagami show no evidence of aqueous activity, though their primary basaltic mineralogies show many similarities to that of Nakhla. Fractures within Los Angeles and Zagami are fresh and unweathered, and no secondarily deposited phases were found. The environmental conditions suggested by the mineral phases in the Nakhla, Los Angeles, and Zagami meteorites can be used to assess their potential to act as microbial substrates for possible Martian life. Future Mars sample return missions have been proposed to involve the selection and caching of rock samples for return to the Earth. This will require intensive prioritization of samples on the surface and a need to vector towards areas with higher potential for astrobiologically interesting samples. The comparative methodologies developed here with Martian meteorites can be applied to unknown samples recovered from the surface of Mars to aid in mission operations and logistics. [1] J.C. Bridges et al., 2006. Journal of the Geological Society, London 163:229-251. [2] G. Southam et al., 2007. Treatise on Geophysics: Planets and Moons 10:421-438. [3] J.C. Bridges et al., 2001 Space Science Reviews 96: 365-392. [4] I.H. Thorseth et al., 1992. Geochimica et Cosmochimica Acta 56:845-850. [5] H.G. Changela et al., 2011 Meteoritics & Planetary Science 45(12):1847-1867.

Effect of Acid on Surface Hydroxyl Groups on Kaolinite and Montmorillonite

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

Sihvonen, Sarah K.; Murphy, Kelly A.; Washton, Nancy M.

Mineral dust aerosol participates in heterogeneous chemistry in the atmosphere. In particular, the hydroxyl groups on the surface of aluminosilicate clay minerals are important for heterogeneous atmospheric processes. These functional groups may be altered by acidic processing during atmospheric transport. In this study, we exposed kaolinite (KGa-1b) and montmorillonite (STx-1b) to aqueous sulfuric acid and then rinsed the soluble reactants and products off in order to explore changes to functional groups on the mineral surface. To quantify the changes due to acid treatment of edge hydroxyl groups, we use 19F magic angle spinning nuclear magnetic resonance spectroscopy and a probemore » molecule, 3,3,3-trifluoropropyldimethylchlorosilane. We find that the edge hydroxyl groups (OH) increase in both number and density with acid treatment. Chemical reactions in the atmosphere may be impacted by the increase in OH at the mineral edge.« less

Groundwater–surface water mixing shifts ecological assembly processes and stimulates organic carbon turnover

PubMed Central

Stegen, James C.; Fredrickson, James K.; Wilkins, Michael J.; Konopka, Allan E.; Nelson, William C.; Arntzen, Evan V.; Chrisler, William B.; Chu, Rosalie K.; Danczak, Robert E.; Fansler, Sarah J.; Kennedy, David W.; Resch, Charles T.; Tfaily, Malak

2016-01-01

Environmental transitions often result in resource mixtures that overcome limitations to microbial metabolism, resulting in biogeochemical hotspots and moments. Riverine systems, where groundwater mixes with surface water (the hyporheic zone), are spatially complex and temporally dynamic, making development of predictive models challenging. Spatial and temporal variations in hyporheic zone microbial communities are a key, but understudied, component of riverine biogeochemical function. Here, to investigate the coupling among groundwater–surface water mixing, microbial communities and biogeochemistry, we apply ecological theory, aqueous biogeochemistry, DNA sequencing and ultra-high-resolution organic carbon profiling to field samples collected across times and locations representing a broad range of mixing conditions. Our results indicate that groundwater–surface water mixing in the hyporheic zone stimulates heterotrophic respiration, alters organic carbon composition, causes ecological processes to shift from stochastic to deterministic and is associated with elevated abundances of microbial taxa that may degrade a broad suite of organic compounds. PMID:27052662

Groundwater-surface water mixing shifts ecological assembly processes and stimulates organic carbon turnover.

PubMed

Stegen, James C; Fredrickson, James K; Wilkins, Michael J; Konopka, Allan E; Nelson, William C; Arntzen, Evan V; Chrisler, William B; Chu, Rosalie K; Danczak, Robert E; Fansler, Sarah J; Kennedy, David W; Resch, Charles T; Tfaily, Malak

2016-04-07

Environmental transitions often result in resource mixtures that overcome limitations to microbial metabolism, resulting in biogeochemical hotspots and moments. Riverine systems, where groundwater mixes with surface water (the hyporheic zone), are spatially complex and temporally dynamic, making development of predictive models challenging. Spatial and temporal variations in hyporheic zone microbial communities are a key, but understudied, component of riverine biogeochemical function. Here, to investigate the coupling among groundwater-surface water mixing, microbial communities and biogeochemistry, we apply ecological theory, aqueous biogeochemistry, DNA sequencing and ultra-high-resolution organic carbon profiling to field samples collected across times and locations representing a broad range of mixing conditions. Our results indicate that groundwater-surface water mixing in the hyporheic zone stimulates heterotrophic respiration, alters organic carbon composition, causes ecological processes to shift from stochastic to deterministic and is associated with elevated abundances of microbial taxa that may degrade a broad suite of organic compounds.

URANIUM DECONTAMINATION WITH RESPECT TO ZIRCONIUM

DOEpatents

Vogler, S.; Beederman, M.

1961-05-01

A process is given for separating uranium values from a nitric acid aqueous solution containing uranyl values, zirconium values and tetravalent plutonium values. The process comprises contacting said solution with a substantially water-immiscible liquid organic solvent containing alkyl phosphate, separating an organic extract phase containing the uranium, zirconium, and tetravalent plutonium values from an aqueous raffinate, contacting said organic extract phase with an aqueous solution 2M to 7M in nitric acid and also containing an oxalate ion-containing substance, and separating a uranium- containing organic raffinate from aqueous zirconium- and plutonium-containing extract phase.

Process for recovering chaotropic anions from an aqueous solution also containing other ions

DOEpatents

Rogers, Robin; Horwitz, E. Philip; Bond, Andrew H.

1999-01-01

A solid/liquid process for the separation and recovery of chaotropic anions from an aqueous solution is disclosed. The solid support comprises separation particles having surface-bonded poly(ethylene glycol) groups, whereas the aqueous solution from which the chaotropic anions are separated contains a poly(ethylene glycol) liquid/liquid biphase-forming amount of a dissolved salt (lyotrope). A solid/liquid phase admixture of separation particles containing bound chaotropic anions in such an aqueous solution is also contemplated, as is a chromatography apparatus containing that solid/liquid phase admixture.

Process for recovering chaotropic anions from an aqueous solution also containing other ions

DOEpatents

Rogers, R.; Horwitz, E.P.; Bond, A.H.

1999-03-30

A solid/liquid process for the separation and recovery of chaotropic anions from an aqueous solution is disclosed. The solid support comprises separation particles having surface-bonded poly(ethylene glycol) groups, whereas the aqueous solution from which the chaotropic anions are separated contains a poly(ethylene glycol) liquid/liquid biphase-forming amount of a dissolved salt (lyotrope). A solid/liquid phase admixture of separation particles containing bound chaotropic anions in such an aqueous solution is also contemplated, as is a chromatography apparatus containing that solid/liquid phase admixture. 19 figs.

Prioritized List of Research Needs to support MRWFD Case Study Flowsheet Advancement

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

Law, Jack Douglas; Soelberg, Nicholas Ray

In FY-13, a case study evaluation was performed of full recycle technologies for both the processing of light-water reactor (LWR) used nuclear fuels as well as fast reactor (FR) fuel in the full recycle option. This effort focused on the identification of the case study processes and the initial preparation of material balance flowsheets for the identified technologies. In identifying the case study flowsheets, it was decided that two cases would be developed: one which identifies the flowsheet as currently developed and another near-term target flowsheet which identifies the flowsheet as envisioned within two years, pending the results of ongoingmore » research. The case study focus is on homogeneous aqueous recycle of the U/TRU resulting from the processing of LWR fuel as feed for metal fuel fabrication. The metal fuel is utilized in a sodium-cooled fast reactor, and the used fast reactor fuel is processed using electrochemical separations. The recovered U/TRU from electrochemical separations is recycled to fuel fabrication and the fast reactor. Waste streams from the aqueous and electrochemical processing are treated and prepared for disposition. Off-gas from the separations and waste processing are also treated. As part of the FY-13 effort, preliminary process unknowns and research needs to advance the near-term target flowsheets were identified. In FY-14, these research needs were updated, expanded and prioritized. This report again updates the prioritized list of research needs based upon results to date in FY-15. The research needs are listed for each of the main portions of the flowsheet: 1) Aqueous headend, 2) Headend tritium pretreatment off-gas, 3) Aqueous U/Pu/Np recovery, 4) Aqueous TRU product solidification, 5) Aqueous actinide/lanthanide separation, 6) Aqueous off-gas treatment, 7) Aqueous HLW management, 8) Treatment of aqueous process wastes, 9) E-chem actinide separations, 10) E-chem off-gas, 11) E-chem HLW management. The identified research needs were prioritized within each of these areas. No effort was made to perform an overall prioritization. This information will be used by the MRWFD Campaign leadership in research planning for FY-16. Additionally, this information will be incorporated into the next version of the Case Study Report scheduled to be issued September 2015.« less

Compound-Specific Carbon Isotope Compositions of Aldehydes and Ketones in the Tagish Lake Meteorite

NASA Astrophysics Data System (ADS)

Simkus, D. N.; Aponte, J. C.; Hilts, R. W.; Elsila, J. E.; Herd, C. D. K.

2016-08-01

Aldehydes and ketones detected in the Tagish Lake meteorite are highly depleted in 13C, indicating that they are unlikely relic Strecker synthesis precursors. Potential sources for these compounds and the effects of aqueous alteration are discussed.

Influence of formulation and processing variables on properties of itraconazole nanoparticles made by advanced evaporative precipitation into aqueous solution.

PubMed

Bosselmann, Stephanie; Nagao, Masao; Chow, Keat T; Williams, Robert O

2012-09-01

Nanoparticles, of the poorly water-soluble drug, itraconazole (ITZ), were produced by the Advanced Evaporative Precipitation into Aqueous Solution process (Advanced EPAS). This process combines emulsion templating and EPAS processing to provide improved control over the size distribution of precipitated particles. Specifically, oil-in-water emulsions containing the drug and suitable stabilizers are sprayed into a heated aqueous solution to induce precipitation of the drug in form of nanoparticles. The influence of processing parameters (temperature and volume of the heated aqueous solution; type of nozzle) and formulation aspects (stabilizer concentrations; total solid concentrations) on the size of suspended ITZ particles, as determined by laser diffraction, was investigated. Furthermore, freeze-dried ITZ nanoparticles were evaluated regarding their morphology, crystallinity, redispersibility, and dissolution behavior. Results indicate that a robust precipitation process was developed such that size distribution of dispersed nanoparticles was shown to be largely independent across the different processing and formulation parameters. Freeze-drying of colloidal dispersions resulted in micron-sized agglomerates composed of spherical, sub-300-nm particles characterized by reduced crystallinity and high ITZ potencies of up to 94% (w/w). The use of sucrose prevented particle agglomeration and resulted in powders that were readily reconstituted and reached high and sustained supersaturation levels upon dissolution in aqueous media.

X-Ray Amorphous Phases in Antarctica Dry Valley Soils: Insight into Aqueous Alteration Processes on Mars?

NASA Technical Reports Server (NTRS)

Ming, D. W.; Morris, R. V.; Rampe, E. B.; Golden, D. C.; Quinn, J. E.

2015-01-01

The Chemistry and Mineralogy (CheMin) instrument onboard the Mars Curiosity rover has detected abundant amounts (approx. 25-30 weight percentage) of X-ray amorphous materials in a windblown deposit (Rocknest) and in a sedimentary mudstone (Cumberland and John Klein) in Gale crater, Mars. On Earth, X-ray amorphous components are common in soils and sediments, but usually not as abundant as detected in Gale crater. One hypothesis for the abundant X-ray amorphous materials on Mars is limited interaction of liquid water with surface materials, kinetically inhibiting maturation to more crystalline phases. The objective of this study was to characterize the chemistry and mineralogy of soils formed in the Antarctica Dry Valleys, one of the driest locations on Earth. Two soils were characterized from different elevations, including a low elevation, coastal, subxerous soil in Taylor Valley and a high elevation, ultraxerous soil in University Valley. A variety of techniques were used to characterize materials from each soil horizon, including Rietveld analysis of X-ray diffraction data. For Taylor Valley soil, the X-ray amorphous component ranged from about 4 weight percentage in the upper horizon to as high as 15 weight percentage in the lowest horizon just above the permafrost layer. Transmission electron microscopy indicated that the presence of short-range ordered (SRO) smectite was the most likely candidate for the X-ray amorphous materials in the Taylor Valley soils. The SRO smectite is likely an aqueous alteration product of mica inherited from granitic materials during glaciation of Taylor Valley. The drier University Valley soils had lower X-ray amorphous contents of about 5 weight percentage in the lowest horizon. The X-ray amorphous materials in University Valley are attributed to nanoparticles of TiO2 and possibly amorphous SiO2. The high abundance of X-ray amorphous materials in Taylor Valley is surprising for one of the driest places on Earth. These materials may have been physically and chemical altered during soil formation, however, the limited interaction with water and low temperatures may result in the formation of "immature" X-ray amorphous or SRO materials. Perhaps, a similar process contributes to the formation of the high content of X-ray amorphous materials detected on Mars.

Process for separating and recovering an anionic dye from an aqueous solution

DOEpatents

Rogers, Robin; Horwitz, E. Philip; Bond, Andrew H.

1998-01-01

A solid/liquid phase process for the separation and recovery of an anionic dye from an aqueous solution is disclosed. The solid phase comprises separation particles having surface-bonded poly(ethylene glycol) groups, whereas the aqueous solution from which the anionic dye molecules are separated contains a poly(ethylene glycol) liquid/liquid biphase-forming amount of a dissolved lyotropic salt. After contact between the aqueous solution and separation particles, the anionic dye is bound to the particles. The bound anionic dye molecules are freed from the separation particles by contacting the anionic dye-bound particles with an aqueous solution that does not contain a poly(ethylene glycol) liquid/liquid biphase-forming amount of a dissolved lyotropic salt to form an aqueous anionic dye solution whose anionic dye concentration is preferably higher than that of the initial dye-containing solution.

Is the U-B color sufficient for identifying water of hydration on solar system bodies?

NASA Technical Reports Server (NTRS)

Vilas, Faith

1995-01-01

The U-B color has been suggested as a predictor of the presence of water of hydration on asteroids. Photometry from the Eight-Color Asteroid Survey (ECAS) was used to test this concept. An overlap in U-B color prevents this magnitude difference from distinguishing between surface material that was thermally processed at higher temperatures and surface material that was aqueously altered. Two tests of the presence of water of hydration using visible spectral region photometry failed to flag those few higher albedo M- and E-class asteroids having photometry that shows a 3.0-micrometers water of hydration absorption. These asteroids probably contain little or no oxidized iron in their surface material.

Materials Fabrication from Bombyx mori Silk Fibroin

PubMed Central

Rockwood, Danielle N.; Preda, Rucsanda C.; Yücel, Tuna; Wang, Xiaoqin; Lovett, Michael L.; Kaplan, David L.

2013-01-01

Silk fibroin, derived from Bombyx mori cocoons, is a widely used and studied protein polymer for biomaterial applications. Silk fibroin has remarkable mechanical properties when formed into different materials, demonstrates biocompatibility, has controllable degradation rates from hours to years, and it can be chemically modified to alter surface properties or to immobilize growth factors. A variety of aqueous or organic solvent processing methods can be used to generate silk biomaterials for a range of applications. In this protocol we include methods to extract silk from B. mori cocoons in order to fabricate hydrogels, tubes, sponges, composites, fibers, microspheres and thin films. These materials can be used directly as biomaterials for implants, as scaffolding in tissue engineering and in vitro disease models, and for drug delivery. PMID:21959241

Martian Analogue Sample Characterization and Spectral Library Development at the Johnson Space Center

NASA Technical Reports Server (NTRS)

Morris, Richard V.

2002-01-01

An extensive collection of Martian analogue samples housed at the Johnson Space Center is the focus of ongoing research by the JSC Mars soil genesis group and their collaborators. Because the major element composition of Martian meteorites and in situ analyses of Martian soils and rocks indicate that Mars is predominantly an iron-rich basaltic world, the focus of active sample collection and analysis is basaltic materials and their hydrolytic (both aqueous and hydrothermal) and sulfatetic alteration products. Described below are the scope of the JSC Mars analogue sample collection, the characterization process, and plans to incorporate the data into spectral libraries for the Mars 2003 Mars Exploration Rover (MER) and Mars 2005 Mars Reconnaissance Orbiter (MRO) CRISM missions.

Treatment of Aqueous Film-Forming Foam by Heat-Activated Persulfate Under Conditions Representative of In Situ Chemical Oxidation

PubMed Central

2017-01-01

Poly- and perfluoroalkyl substances (PFASs) have been detected in an increasing number of water supplies. In many instances, the contamination is associated with the use of PFAS-containing aqueous film-forming foams (AFFF) in firefighting activities. To investigate the potential for remediating AFFF contamination in groundwater with heat-activated persulfate, PFAS oxidation and the generation of transformation products was evaluated under well-controlled conditions. Fluorotelomer- and perfluoroalkyl sulfonamide-based polyfluorinated compounds were transformed to perfluorinated carboxylic acids, which underwent further degradation under acidic conditions produced after persulfate decomposed. The presence of aquifer sediments decreased the efficiency of the remedial process but did not alter the transformation pathways. At high concentrations, the presence of organic solvents, such as those present in AFFF formulations, inhibited transformation of a representative perfluorinated compound, perfluorooctanoic acid. Heat-activated persulfate did not transform perfluorooctanesulfonic acid or perfluorohexanesulfonic acid under any conditions. Despite challenges associated with the creation of acidic conditions in the subsurface, the potential for generation of undesirable transformation products, and the release of toxic metals, heat-activated persulfate may be a useful in situ treatment for sites contaminated with polyfluoroalkyl substances and perfluorocarboxylic acids. PMID:29164864

Sulfate Formation From Acid-Weathered Phylosilicates: Implications for the Aqueous History of Mars

NASA Technical Reports Server (NTRS)

Craig, P. I.; Ming, D. W.; Rampe, E. B.

2014-01-01

Most phyllosilicates on Mars are thought to have formed during the planet's earliest Noachian era, then Mars underwent a global change making the planet's surface more acidic [e.g. 1]. Prevailing acidic conditions may have affected the already existing phyllosilicates, resulting in the formation of sulfates. Both sulfates and phyllosilicates have been identified on Mars in a variety of geologic settings [2] but only in a handful of sites are these minerals found in close spatial proximity to each other, including Mawrth Vallis [3,4] and Gale Crater [5]. While sulfate formation from the acidic weathering of basalts is well documented in the literature [6,7], few experimental studies investigate sulfate formation from acid-weathered phyllosilicates [8-10]. The purpose of this study is to characterize the al-teration products of acid-weathered phyllosilicates in laboratory experiments. We focus on three commonly identified phyllosilicates on Mars: nontronite (Fe-smectite), saponite (Mg-smectite), and montmorillonite (Al-smectite) [1, and references therein]. This information will help constrain the formation processes of sulfates observed in close association with phyllosilicates on Mars and provide a better understanding of the aqueous history of such regions as well as the planet as a whole.

Analysis of Direct Samples of Early Solar System Aqueous Fluids

NASA Technical Reports Server (NTRS)

Zolensky, Michael E.; Bodnar, R J.; Fedele, L.; Yurimoto,H.; Itoh, S.; Fries, M.; Steele, A.

2012-01-01

Over the past three decades we have become increasingly aware of the fundamental importance of water, and aqueous alteration, on primitive solar-system bodies. Some carbonaceous and ordinary chondrites have been altered by interactions with liquid water within the first 10 million years after formation of their parent asteroids. Millimeter to centimeter-sized aggregates of purple halite containing aqueous fluid inclusions were found in the matrix of two freshly-fallen brecciated H chondrite falls, Monahans (1998, hereafter simply "Monahans") (H5) and Zag (H3-6) (Zolensky et al., 1999; Whitby et al., 2000; Bogard et al., 2001) In order to understand origin and evolution of the aqueous fluids inside these inclusions we much measure the actual fluid composition, and also learn the O and H isotopic composition of the water. It has taken a decade for laboratory analytical techniques to catch up to these particular nanomole-sized aqueous samples. We have recently been successful in (1) measuring the isotopic composition of H and O in the water in a few fluid inclusions from the Zag and Monahans halite, (2) mineralogical characterization of the solid mineral phases associated with the aqueous fluids within the halite, and (3) the first minor element analyses of the fluid itself. A Cameca ims-1270 equipped with a cryo-sample-stage of Hokkaido University was specially prepared for the O and H isotopic measurements. The cryo-sample-stage (Techno. I. S. Corp.) was cooled down to c.a. -190 C using liquid nitrogen at which the aqueous fluid in inclusions was frozen. We excavated the salt crystal surfaces to expose the frozen fluids using a 15 keV Cs+ beam and measured negative secondary ions. The secondary ions from deep craters of approximately 10 m in depth emitted stably but the intensities changed gradually during measurement cycles because of shifting states of charge compensation, resulting in rather poor reproducibility of multiple measurements of standard fluid inclusions of +/- 90 0/00(2 sigma) for delta D, and +/- 29 0/00 (2 sigma) for delta O-18. On the other hand, the reproducibility of Delta O-17 is plus or minus 8 /00 (2 sigma ) because the observed variations of isotope ratios follow a mass dependent fractionation law. Variations of delta D of the aqueous fluids range over sog,a 330(90; 2 sigma ) to +1200(90) 0/00 for Monahans and delta 300(96) 0/00 to +90(98)0/00 for Zag. Delta O-17 of aqueous fluids range over delta 16(22) 0/00 to +18(10) 0/00 for Monahans and +3(10) 0/00 to +27(11) 0/00 for Zag. These variations are larger than the reproducibility of standard analyses and suggest that isotope equilibria were under way in the fluids before trapping into halite. The mean values of delta D and Delta O-17 are +290 0/00 and +9 0/00, respectively. The mean values and the variations of these fluids are different from the representative values of ordinary chondrites, verifying our working hypothesis that the fluid inclusion-bearing halites were not indigenous to the H chondrite parent-asteroid but rather represent exogenous material delivered onto the asteroid from a separate cryovolcanically-active body. This initial isotopic work has demonstrated the feasibility of the measurements, but also revealed sample processing and analytical shortcomings that are now being addressed. Examination of solid mineral inclusions within Monahans and Zag halite grains by confocal Raman spectroscopy at the Carnegie Geophysical Laboratory has revealed them to be metal, magnetite, forsteritic olivine (Fo.98), macromolecular carbon (MMC), pyroxenes, feldspar with Raman spectral affinity to anorthoclase and, probably, fine-grained lepidocrocite (FeO(OH)). In addition, one inclusion features aliphatic material with Raman spectral features consistent with a mixture of short-chain aliphatic compounds. We have initiated analyses of the bulk composition of the fluids within the inclusions in Zag and Monahans halites at Virginia Tech by LA ICPMS using angilent 7500ce quadrupole ICPMS and a Lambda Physik GeoLas 193 nm excimer laser ablation system. Preliminary results reveal that the inclusion aqueous fluids contain highly charged cations of Ca, Mg and Fe. The minerals and compounds discovered thus far within Monahans/Zag halites are indicative of an originating body at least partly composed of unequilibrated anhydrous materials (high Fo olivine, pyroxenes, feldspars, possibly the metal) which were subjected to aqueous alteration (the halite parent brine) and containing a light organic component (the short-chain aliphatic compounds). This material was ejected from the originating body with little or no disruption, as evidenced with the presence of fluid inclusions. An actively geysering body similar to modern Enceladus (Postberg et al., 2011) may be a reasonable analogue in this respect. Also, the originating body should have been within close proximity to the H chondrite parent in order to generate the number of halite grains seen in Monahans and Zag. Other candidates for Monahans/Zag halite parent bodie(s) may include a young Ceres with its possible liquid ocean, or Main Belt comets.

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.

Effects of an aqueous extract of Orbignya phalerata Mart on locomotor activity and motor coordination in mice and as antioxidant in vitro.

PubMed

Silva, A P dos S; Cerqueira, G S; Nunes, L C C; de Freitas, R M

2012-03-01

The antioxidant activities of aqueous extract (AE) of Orbignya phalerata were assessed in vitro as well as its effect on locomotor activity and motor coordination in mice. AE does not possesses a strong antioxidant potential according to the scavenging assays; it also did not present scavenger activity in vitro. Following oral administration, AE (1, 2 and 3 g/kg) did not significantly change the motor activity of animals when compared with the control group, up to 24 h after administration and did not alter the remaining time of the animals on the Rota-rod apparatus. Further studies currently in progress will enable us to understand the mechanisms of action of the aqueous extract of Orbignya phalerata widely used in Brazilian flok medicine.

Aqueous geochemistry on Mars: Possible clues from salts and clays in SNC meteorites

NASA Technical Reports Server (NTRS)

Gooding, James L.

1992-01-01

All subgroups of the shergottite, nakhlite, and chassignite (SNC) meteorites contain traces of water precipitated minerals that include various combinations of carbonates, sulfates, halides, ferric oxides, and aluminosilicate clays of preterrestrial origin. Oxygen three-isotope analysis of thermally extracted bulk water has confirmed that at least some of the water in SNC's is, indeed, extraterrestrial. A mixture of aqueous precipitates found in the SNC's, comprising smectite, illite, and gypsum (with minor halite +/- calcite and hematite), provides a self-consistent, though not unique, model for the bulk elemental composition of surface sediments at the Viking Lander sites. Therefore, if the salts and clays in SNC's are truly linked to aqueous alteration and soil formation on Mars, then the suite of SNC secondary minerals might provide the best currently available insight into near-surface martian chemistry.

Investigations of per- and polyfluorinated compounds in environmental samples and contemporary products

EPA Science Inventory

Due to the usefulness of per- and polyfluoro alkyl substances (PFAS), they are in many applications and products, such as fluoropolymer dispersions, fluoro-surfactants, paper/paperboard coatings, and aqueous film forming foam (AFFF). Recent regulatory pressure has altered the che...

Silica Retention and Enrichment in Open-System Chemical Weathering on Mars

NASA Technical Reports Server (NTRS)

Yen, A. S.; Ming, D. W.; Gellert, R.; Clark, B. C.; Mittlefehldt, D. W.; Morris, R. V.; Thompson, L. M.; Berger, J.

2015-01-01

Chemical signatures of weathering are evident in the Alpha Particle X-ray Spectrometer (APXS) datasets from Gusev Crater, Meridiani Planum, and Gale Crater. Comparisons across the landing sites show consistent patterns indicating silica retention and/or enrichment in open-system aqueous alteration.

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

Yang Bin; Jewitt, David, E-mail: yangbin@ifa.hawaii.ed, E-mail: jewitt@ucla.ed

Spectrally blue (B-type) asteroids are rare, with the second discovered asteroid, Pallas, being the largest and most famous example. We conducted a focused, infrared spectroscopic survey of B-type asteroids to search for water-related features in these objects. Our results show that the negative optical spectral slope of some B-type asteroids is due to the presence of a broad absorption band centered near 1.0 {mu}m. The 1 {mu}m band can be matched in position and shape using magnetite (Fe{sub 3}O{sub 4}), which is an important indicator of past aqueous alteration in the parent body. Furthermore, our observations of B-type asteroid (335)more » Roberta in the 3 {mu}m region reveal an absorption feature centered at 2.9 {mu}m, which is consistent with the absorption due to phyllosilicates (another hydration product) observed in CI chondrites. The new observations suggest that at least some B-type asteroids are likely to have incorporated significant amounts of water ice and to have experienced intensive aqueous alteration.« less

Spectral filtering for plant production

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

Young, R.E.; McMahon, M.J.; Rajapakse, N.C.

1994-12-31

Research to date suggests that spectral filtering can be an effective alternative to chemical growth regulators for altering plant development. If properly implemented, it can be nonchemical and environmentally friendly. The aqueous CuSO{sub 4}, and CuCl{sub 2} solutions in channelled plastic panels have been shown to be effective filters, but they can be highly toxic if the solutions contact plants. Some studies suggest that spectral filtration limited to short EOD intervals can also alter plant development. Future research should be directed toward confirmation of the influence of spectral filters and exposure times on a broader range of plant species andmore » cultivars. Efforts should also be made to identify non-noxious alternatives to aqueous copper solutions and/or to incorporate these chemicals permanently into plastic films and panels that can be used in greenhouse construction. It would also be informative to study the impacts of spectral filters on insect and microbal populations in plant growth facilities. The economic impacts of spectral filtering techniques should be assessed for each delivery methodology.« less

Coordinated mineralogical and isotopic analyses of a cosmic symplectite discovered in a comet 81P/Wild 2 sample

NASA Astrophysics Data System (ADS)

Nguyen, Ann N.; Berger, Eve L.; Nakamura-Messenger, Keiko; Messenger, Scott; Keller, Lindsay P.

2017-09-01

We have discovered in a Stardust mission terminal particle a unique mineralogical assemblage of symplectically intergrown pentlandite ((Fe,Ni)9S8) and nanocrystalline maghemite (γ-Fe2O3). Mineralogically similar cosmic symplectites (COS) have only been found in the primitive carbonaceous chondrite Acfer 094 and are believed to have formed by aqueous alteration. The O and S isotopic compositions of the Wild 2 COS are indistinguishable from terrestrial values. The metal and sulfide precursors were thus oxidized by an isotopically equilibrated aqueous reservoir either inside the snow line, in the Wild 2 comet, or in a larger Kuiper Belt object. Close association of the Stardust COS with a Kool mineral assemblage (kosmochloric Ca-rich pyroxene, FeO-rich olivine, and albite) that likely originated in the solar nebula suggests the COS precursors also had a nebular origin and were transported from the inner solar system to the comet-forming region after they were altered.

Competitive and Cooperative Effects during Nickel Adsorption to Iron Oxides in the Presence of Oxalate

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

Flynn, Elaine D.; Catalano, Jeffrey G.

Iron oxides are ubiquitous in soils and sediments and play a critical role in the geochemical distribution of trace elements and heavy metals via adsorption and coprecipitation. The presence of organic acids may potentially alter how metals associate with iron oxide minerals through a series of cooperative or competitive processes: solution complexation, ternary surface complexation, and surface site competition. The macroscopic and molecular-scale effects of these processes were investigated for Ni adsorption to hematite and goethite at pH 7 in the presence of oxalate. The addition of this organic acid suppresses Ni uptake on both minerals. Aqueous speciation suggests thatmore » this is dominantly the result of oxalate complexing and solubilizing Ni. Comparison of the Ni surface coverage to the concentration of free (uncomplexed) Ni 2+ in solution suggests that the oxalate also alters Ni adsorption affinity. EXAFS and ATR-FTIR spectroscopies indicate that these changes in binding affinity are due to the formation of Ni–oxalate ternary surface complexes. These observations demonstrate that competition between dissolved oxalate and the mineral surface for Ni overwhelms the enhancement in adsorption associated with ternary complexation. Oxalate thus largely enhances Ni mobility, thereby increasing micronutrient bioavailability and inhibiting contaminant sequestration.« less

History of Nebular Processing Traced by Silicate Stardust in IDPS

NASA Technical Reports Server (NTRS)

Messenger, Scott R.; Keller, L. P.; Nakamura-Messenger, K.

2010-01-01

Chondritic porous interplanetary dust particles (CP-IDPs) may be the best preserved remnants of primordial solar system materials, in part because they were not affected by parent body hydrothermal alteration. Their primitive characteristics include fine grained, unequilibrated, anhydrous mineralogy, enrichment in volatile elements, and abundant molecular cloud material and silicate stardust. However, while the majority of CP-IDP materials likely derived from the Solar System, their formation processes and provenance are poorly constrained. Stardust abundances provide a relative measure of the extent of processing that the Solar System starting materials has undergone in primitive materials. For example, among primitive meteorites silicate stardust abundances vary by over two orders of magnitude (less than 10-200 ppm). This range of abundances is ascribed to varying extents of aqueous processing in the meteorite parent bodies. The higher average silicate stardust abundances among CP-IDPs (greater than 375 ppm) are thus attributable to the lack of aqueous processing of these materials. Yet, silicate stardust abundances in IDPs also vary considerably. While the silicate stardust abundance in IDPs having anomalous N isotopic compositions was reported to be 375 ppm, the abundance in IDPs lacking N anomalies is less than 10 ppm. Furthermore, these values are significantly eclipsed among some IDPs with abundances ranging from 2,000 ppm to 10,000 ppm. Given that CP-IDPs have not been significantly affected by parent body processes, the difference in silicate stardust abundances among these IDPs must reflect varying extents of nebular processing. Here we present recent results of a systematic coordinated mineralogical/isotopic study of large cluster IDPs aimed at (1) characterizing the mineralogy of presolar silicates and (2) delineating the mineralogical and petrographic characteristics of IDPs with differing silicate stardust abundances. One of the goals of this study is to better understand the earliest stages of evolution of the Solar System starting materials.

Gas-solid carbonation as a current alternative origin for carbonates in Martian regolith

NASA Astrophysics Data System (ADS)

Garenne, A.; Montes-Hernandez, G.; Beck, P.; Schmitt, B.; Brissaud, O.

2011-12-01

Carbonates are abundant sedimentary minerals at the surface and sub-surface of Earth and they have been proposed as tracers of liquid water in extraterrestrial environments (e.g. at Mars surface). Its formation mechanism is since generally associated with aqueous alteration processes. Recently, carbonates minerals have been discovered on Mars surface by different orbital or rovers missions. In particular, the phoenix mission has measured from 1 to 5% of calcium carbonate (calcite type). These occurrences have been reported in area were the relative humidity is significantly high (Boynton et al., 2009). The small concentration of carbonates suggests an alternative process than carbonation in aqueous conditions. Such an observation might rather point toward a possible formation mechanism by dust-gas reaction under current Martian conditions. For this reason, in the present study, we designed an experimental setup consisting of an infrared microscope coupled to a cryogenic reaction cell (IR-CryoCell setup) in order to investigate the gas-solid carbonation of three different mineral precursors for carbonates (Ca and Mg hydroxides, and a hydrated Ca silicate formed from Ca2SiO4) at low temperature (from -10 to 25°C) and at reduced CO2 pressure (from 100 to 1000 mbar). These mineral materials are crucial precursors to form respective Ca and Mg carbonates in humid environments (0 < relative humidity < 100%) at dust-CO2 or dust-water ice-CO2 interfaces. The results have revealed a significant and fast carbonation process for Ca hydroxide and hydrated Ca silicate. Conversely, slight carbonation process was observed for Mg hydroxide. These results suggest that gas-solid carbonation process or carbonate formation at the dust-water ice-CO2 interfaces could be a currently active Mars surface process. We note that the carbonation process at low temperature (<0°C) described in the present study could also have important implications on the dust-water ice-CO2 interactions in cold terrestrial environments (e.g. Antarctic).

Surveying Clay Mineral Diversity in the Murray Formation, Gale Crater, Mars

NASA Technical Reports Server (NTRS)

Bristow, T.F.; Blake, D. F..; Vaniman, D. T.; Chipera, S. J.; Rampe, E. B.; Grotzinger, J. P.; McAdam, A. C.; Ming, D. W..; Morrison, S. M.; Yen, A. S.;

Aqueous and pyrochemical reprocessing of actinide fuels

NASA Astrophysics Data System (ADS)

Toth, L. Mac; Bond, Walter D.; Avens, Larry R.

1993-02-01

Processing of the nuclear fuel actinides has developed in two independent directions—aqueous processing and pyroprocessing. Similarities in the two processes, their goals, and restraints are indicated in brief parallel descriptions along with distinguishing advantages and areas of future development. It is suggested that from a technical viewpoint, the ultimate process might be a hybrid which incorporates the best steps of each process.

PROCESS FOR DECONTAMINATING THORIUM AND URANIUM WITH RESPECT TO RUTHENIUM

DOEpatents

Meservey, A.A.; Rainey, R.H.

1959-10-20

The control of ruthenium extraction in solvent-extraction processing of neutron-irradiated thorium is presented. Ruthenium is rendered organic-insoluble by the provision of sulfite or bisulfite ions in the aqueous feed solution. As a result the ruthenium remains in the aqueous phase along with other fission product and protactinium values, thorium and uranium values being extracted into the organic phase. This process is particularly applicable to the use of a nitrate-ion-deficient aqueous feed solution and to the use of tributyl phosphate as the organic extractant.

Process for separating and recovering an anionic dye from an aqueous solution

DOEpatents

Rogers, R.; Horwitz, E.P.; Bond, A.H.

1998-01-13

A solid/liquid phase process for the separation and recovery of an anionic dye from an aqueous solution is disclosed. The solid phase comprises separation particles having surface-bonded poly(ethylene glycol) groups, whereas the aqueous solution from which the anionic dye molecules are separated contains a poly(ethylene glycol) liquid/liquid biphase-forming amount of a dissolved lyotropic salt. After contact between the aqueous solution and separation particles, the anionic dye is bound to the particles. The bound anionic dye molecules are freed from the separation particles by contacting the anionic dye-bound particles with an aqueous solution that does not contain a poly(ethylene glycol) liquid/liquid biphase-forming amount of a dissolved lyotropic salt to form an aqueous anionic dye solution whose anionic dye concentration is preferably higher than that of the initial dye-containing solution. 7 figs.

Continuous-flow ultrasound assisted oxidative desulfurization (UAOD) process: An efficient diesel treatment by injection of the aqueous phase.

PubMed

Rahimi, Masoud; Shahhosseini, Shahrokh; Movahedirad, Salman

2017-11-01

A new continuous-flow ultrasound assisted oxidative desulfurization (UAOD) process was developed in order to decrease energy and aqueous phase consumption. In this process the aqueous phase is injected below the horn tip leading to enhanced mixing of the phases. Diesel fuel as the oil phase with sulfur content of 1550ppmw and an appropriate mixture of hydrogen peroxide and formic acid as the aqueous phase were used. At the first step, the optimized condition for the sulfur removal has been obtained in the batch mode operation. Hence, the effect of more important oxidation parameters; oxidant-to-sulfur molar ratio, acid-to-sulfur molar ratio and sonication time were investigated. Then the optimized conditions were obtained using Response Surface Methodology (RSM) technique. Afterwards, some experiments corresponding to the best batch condition and also with objective of minimizing the residence time and aqueous phase to fuel volume ratio have been conducted in a newly designed double-compartment reactor with injection of the aqueous phase to evaluate the process in a continuous flow operation. In addition, the effect of nozzle diameter has been examined. Significant improvement on the sulfur removal was observed specially in lower sonication time in the case of dispersion method in comparison with the conventional contact between two phases. Ultimately, the flow pattern induced by ultrasonic device, and also injection of the aqueous phase were analyzed quantitatively and qualitatively by capturing the sequential images. Copyright © 2017 Elsevier B.V. All rights reserved.

Internal load management in eutrophic, anoxic environments. The role of natural zeolite.

NASA Astrophysics Data System (ADS)

Gianni, Areti; Zacharias, Ierotheos

2015-04-01

During the last decades, the increase of the nutrient and organic load inflows in the coastal zone increased the number of the anoxic environments. Inputs' control constitutes one of the basic practices for the eutrophic/anoxic aquatic ecosystems management. However, the induced changes at the ecosystem characteristics resulting from the trophic state alteration, and anoxic conditions prevalence, render the ecosystem's restoration difficult if not impossible. Bottom water anoxia accelerates PO43-, NH4+ and S2- recycling and accumulation from organic matter decomposition. This, toxic layer is a permanent menace for the balance of the entire ecosystem, as it can supply PO43-, NH4+ and S2- to the surface layers altering their qualitative character and threatening the welfare of fishes and other aquatic organisms. Having as objective the water basins' internal load control and based on practices are used in eutrophic environments' restoration, this study is referred to the role of the natural zeolite in eutrophic/anoxic ecosystems management. For the first time are presented, results from S2- removal experiments using the zeolitic mineral mordenite, [(Na2, Ca, K2)4 (H2O)28] [Al8Si40O96]. Four different sets of experiments were conducted, in order to examine zeolite's removal capacity of S2- in aquatic solutions, under a wide range of physicochemical parameters. More specific: a) the effect of initial pH on the removal process, b) the removal process kinetics, c) the removal process isotherms and d) the effect of salinity on the removal process were studied. Natural zeolite has the ability to neutralize the pH of aqueous solutions, thus all the experiments were practically performed at pH 7. Initially sulfides concentration range from 1 to 10mg/l. Zeolite's removal capability appeared to be directly depended on the S2- initial concentration. For initial concentration of 1mg/l, the removal rate reached up to 90% after 24h. The maximum zeolite removal capacity was calculated equal to 123.1 10-3 mg/g S2-. Zeolite removal capacity varied by about 10% as the solution's salinity varied from 0 to 35‰. This study emphasizes in the zeolite ability to remove dissolved sulfides from aqueous solutions. According to literature, natural zeolite is particularly effective in removing ammonium from aquatic solutions, while due to its negative charge zeolite doesn't adsorb phosphate ions. However, in the presence of cations (Ca+2, Na+, K+) in the aquatic solution it turns to the appropriate substrate for the formed phosphate salts. In conclusion, zeolite is a natural inert material, capable to remove from aqueous solutions forms of nitrogen, phosphorus and sulfur. Due to this ability zeolite could play a key role, in eutrophic/anoxic environments restoration efforts, since PO43-, NH4+ and H2S constitute the three aspects of the problem called anoxic basins' internal load.

Enabling aqueous processing for crack-free thick electrodes

DOE PAGES

Du, Zhijia; Rollag, K. M.; Li, J.; ...

2017-04-14

Aqueous processing of thick electrodes for Li-ion cells promises to increase energy density due to increased volume fraction of active materials, and to reduce cost due to the elimination of the toxic solvents. Here in this paper this work reports the processing and characterization of aqueous processed electrodes with high areal loading and associated full pouch cell performance. Cracking of the electrode coatings becomes a critical issue for aqueous processing of the positive electrode as areal loading increases above 20–25 mg/cm 2 (~4 mAh/cm 2). Crack initiation and propagation, which was observed during drying via optical microscopy, is related tomore » the build-up of capillary pressure during the drying process. The surface tension of water was reduced by the addition of isopropyl alcohol (IPA), which led to improved wettability and decreased capillary pressure during drying. The critical thickness (areal loading) without cracking increased gradually with increasing IPA content. The electrochemical performance was evaluated in pouch cells. Electrodes processed with water/IPA (80/20 wt%) mixture exhibited good structural integrity with good rate performance and cycling performance.« less

A COMPOSITE HOLLOW FIBER MEMBRANE-BASED PERVAPORATION PROCESS FOR SEPARATION OF VOCS FROM AQUEOUS SURFACTANT SOLUTIONS. (R825511C027)

EPA Science Inventory

The separation and recovery of VOCs from surfactant-containing aqueous solutions by a composite hollow fiber membrane-based pervaporation process has been studied. The process employed hydrophobic microporous polypropylene hollow fibers having a thin plasma polymerized silicon...

PRETREATMENT AND FRACTIONATION OF CORN STOVER BY AMMONIA RECYCLE PERCOLATION PROCESS. (R831645)

EPA Science Inventory

Corn stover was pretreated with aqueous ammonia in a flow-through column reactor,
a process termed as Ammonia Recycle Percolation (ARP). The aqueous ammonia causes
swelling and efficient delignification of biomass at high temperatures. The ARP
process solubilizes abou...

Weathering of the New Albany Shale, Kentucky: II. Redistribution of minor and trace elements

USGS Publications Warehouse

Tuttle, M.L.W.; Breit, G.N.; Goldhaber, M.B.

2009-01-01

During weathering, elements enriched in black shale are dispersed in the environment by aqueous and mechanical transport. Here a unique evaluation of the differential release, transport, and fate of Fe and 15 trace elements during progressive weathering of the Devonian New Albany Shale in Kentucky is presented. Results of chemical analyses along a weathering profile (unweathered through progressively weathered shale to soil) describe the chemically distinct pathways of the trace elements and the rate that elements are transferred into the broader, local environment. Trace elements enriched in the unweathered shale are in massive or framboidal pyrite, minor sphalerite, CuS and NiS phases, organic matter and clay minerals. These phases are subject to varying degrees and rates of alteration along the profile. Cadmium, Co, Mn, Ni, and Zn are removed from weathered shale during sulfide-mineral oxidation and transported primarily in aqueous solution. The aqueous fluxes for these trace elements range from 0.1 g/ha/a (Cd) to 44 g/ha/a (Mn). When hydrologic and climatic conditions are favorable, solutions seep to surface exposures, evaporate, and form Fe-sulfate efflorescent salts rich in these elements. Elements that remain dissolved in the low pH (<4) streams and groundwater draining New Albany Shale watersheds become fixed by reactions that increase pH. Neutralization of the weathering solution in local streams results in elements being adsorbed and precipitated onto sediment surfaces, resulting in trace element anomalies. Other elements are strongly adsorbed or structurally bound to solid phases during weathering. Copper and U initially are concentrated in weathering solutions, but become fixed to modern plant litter in soil formed on New Albany Shale. Molybdenum, Pb, Sb, and Se are released from sulfide minerals and organic matter by oxidation and accumulate in Fe-oxyhydroxide clay coatings that concentrate in surface soil during illuviation. Chromium, Ti, and V are strongly correlated with clay abundance and considered to be in the structure of illitic clay. Illite undergoes minimal alteration during weathering and is concentrated during illuvial processes. Arsenic concentration increases across the weathering profile and is associated with the succession of secondary Fe(III) minerals that form with progressive weathering. Detrital fluxes of particle-bound trace elements range from 0.1 g/ha/a (Sb) to 8 g/ha/a (Mo). Although many of the elements are concentrated in the stream sediments, changes in pH and redox conditions along the sediment transport path could facilitate their release for aqueous transport.

I-Xe Dating: The Time Line of Chondrule Formation and Metamorphism in LL Chondrites

NASA Technical Reports Server (NTRS)

Pravdivtseva, O. V.; Hohenberg, C. M.; Meshik, A. P.

2005-01-01

Refractory inclusions, considered to be the oldest solids formed in the solar nebula. (4567.2 0.6 Ma) [1], are common in many carbonaceous and in some ordinary and enstatite chondrites. High-precision Pb- Pb ages for CAI s and chondrules (from different meteorites) suggested that chondrule formation appeared to have started about 2 Ma later than that of CAIs [1]. However, recent 26Al/26Mg data suggest simultaneous formation of CAI s and chondrules in Allende [2]. The I-Xe ages of CAI s in Allende are about 2 Ma younger than the I-Xe ages of Allende chondrules [3] but, like all chronometers, the I-Xe system records closure time of its particular host phase. In the case of Allende CAI s, the major iodine-bearing phase is sodalite, a secondary phase presumably formed by aqueous alteration, so I-Xe reflects the post-formational processes in these objects. In chondrules the iodine host phases vary and can reflect formation and/or alteration but, to put chondrule ages on a quantative basis, some problems should first be addressed.

Acid Vapor Weathering of Apatite and Implications for Mars

NASA Technical Reports Server (NTRS)

Hausrath, E. M.; Golden, D. C.; Morris, R. V.; Ming, D. W.

2008-01-01

Phosphorus is an essential nutrient for terrestrial life, and therefore may be important in characterizing habitability on Mars. In addition, phosphate mobility on Mars has been postulated as an indicator of early aqueous activity [1]. Rock surfaces analyzed by the Spirit Mars Exploration Rover indicate elemental concentrations consistent with the loss of a phosphate-containing mineral [2], and the highly altered Paso Robles deposit contains 5% P2O5, modeled as 8-10 % phosphate [3]. Depending on the pH of the solution, phosphate can exist as one of four charge states, which can affect its solubility, reactivity and mobility. Phosphate may therefore prove a useful and interesting tracer of alteration conditions on Mars. Acid vapor weathering has been previously studied as a potentially important process on Mars [4-6], and Paso Robles may have been formed by reaction of volcanic vapors with phosphate-bearing rock [3, 7]. Here we present preliminary results of acid vapor reactions in a Parr vessel [6] using fluorapatite, olivine and glass as single phases and in a mixture.

The influence of ZnO incorporation on the aqueous leaching characteristics of a borosilicate glass

NASA Astrophysics Data System (ADS)

Vance, E. R.; Gregg, D. J.; Karatchevtseva, I.; Griffiths, G. J.; Olufson, K.; Rees, Gregory J.; Hanna, John V.

2017-10-01

With increasing ZnO content, short term aqueous durability enhancement of all elements in borosilicate glasses containing 1.0 and 3.85 wt% ZnO was evident in 7-day PCT-B tests. In 14-day MCC-1 type leach tests conducted at 90 °C, surface alteration was very clear in the undoped glass via the formation of strongly altered amorphous material which tended to spall off the surface. No sign of crystallinity was detected by grazing incidence X-ray diffraction or electron microscopy of the surface layers and the surface material was very rich in silica. For the ZnO-bearing glasses, significant growth of particles following PCT leaching for 7 days was observed, due to a build-up of surface ZnO-containing Si-rich material and possible agglomeration. This alteration layer was also observed in MCC-1 type experiments in which cross-section SEM-EDS data were obtained. Raman, infrared and 11B and 29Si MAS NMR spectroscopy showed only slight changes in boron speciation on the addition of up to 9.1 wt% ZnO. Bulk positron annihilation lifetime spectra (PALS) of glasses containing 0-3.85 wt% ZnO could be analysed with three distinct lifetimes and also showed only slight differences. These results indicate that the basic glass structure was essentially not influenced by the ZnO content and that the passivation of the alteration layer is promoted by ZnO content.

Potential role of Saudi red propolis in alleviating lung damage induced by methicillin resistant Staphylococcus aureus virulence in rats.

PubMed

Saddiq, Amna Ali; Mohamed, Azza Mostafa

2016-07-01

The aim of this study was to explore the protective impact of aqueous extract of Saudi red propolis against rat lung damage induced by the pathogenic bacteria namely methicillin resistant Staphylococcus aureus (MRSA) ATCC 6538 strain. Infected rats were received a single intraperitoneal (i.p.) injection of bacterial suspension at a dose of 1 X 10(6) CFU / 100g body weight. Results showed that oral administration of an aqueous extract of propolis (50mg/100g body weight) daily for two weeks to infected rats simultaneously with bacterial infection, effectively ameliorated the alteration of oxidative stress biomarker, malondialdehyde (MDA), as well as the antioxidant markers, glutathione peroxidase (GPx) and superoxide dismutase (SOD), in lungs of infected rats compared with infected untreated ones. Also, the used propolis extract successfully modulated the alterations in proinflammatory mediators, tumor necrosis factor-α (TNF- α) and vascular endothelial growth factor (VEGF) in serum. In addition, the propolis extract successfully modulated the oxidative DNA damage and the apoptosis biomarker, caspase 3, in lungs of S aureus infected rats compared with infected untreated animals. The biochemical results were supported by histo-pathological observation of lung tissues. In conclusion, the beneficial prophylactic role of the aqueous extract of Saudi red propolis against lung damage induced by methicillin resistant S aureus may be related to the antioxidant, anti-inflammatory, immunomodulatory and antiapoptosis of its active constituents.

Aqueous alteration of the Nakhla meteorite

NASA Technical Reports Server (NTRS)

Gooding, James L.; Zolensky, Michael E.; Wentworth, Susan J.

1991-01-01

Interior samples of three different Nakhla specimens contain an iron-rich silicate 'rust' (which includes a tentatively identified smectite), Ca-carbonate (probably calcite), Ca-sulfate (possibly gypsum or bassanite), Mg-sulfate (possibly epsomite or kieserite), and NaCl (halite); the total abundance of these phases is estimated as less than 0.01 weight percent of the bulk meteorite. Rust veins are truncated and decrepitated by fusion crust and are preserved as faulted segments in partially healed olivine crystals, indicating that the rust is preterrestrial in origin. Because Ca-carbonate and Ca-sulfate are intergrown with the rust, they are also indicated to be of preterrestrial origin. Similar textural evidence regarding origins of the NaCl and Mg-sulfate is lacking. Impure and poorly crystallized sulfates and halides on the fusion crust of the meteorite suggest leaching of interior (preterrestrial) salts from the interior after Makhla arrived on earth, but coincidental addition of these same salts by terrestrial contamination cannot be exluded. At least the clay-like silicate 'rust', Ca-carbonate, and Ca-sulfate were formed by precipitation from water-based solutions on the Nakhla parent planet, although temperature and pressure conditions of aqueous precipitation are unconstrained by currently available data. It is possible that aqueous alteration on the parent body was responsible for the previously observed disturbance of the Rb-Sr geochronometer in Nakhla at or near 1.3 Ga.

Phytochemical and Antibacterial Investigations of the Extracts and Fractions from the Stem Bark of Hymenaea stigonocarpa Mart. ex Hayne and Effect on Ultrastructure of Staphylococcus aureus Induced by Hydroalcoholic Extract

PubMed Central

Dimech, Gustavo Santiago; Soares, Luiz Alberto Lira; Ferreira, Magda Assunção; de Oliveira, Anne Gabrielle Vasconcelos; Carvalho, Maria da Conceição; Ximenes, Eulália Azevedo

2013-01-01

The aim of this study was to investigate the antimicrobial activity of different extracts and fractions obtained from Hymenaea stigonocarpa stem barks. The cyclohexanic, ethyl acetate, ethanol, aqueous, and hydroalcoholic extracts were obtained by maceration. The hydroalcoholic extract was partitioned, which resulted in the ethyl acetate and aqueous fractions. All extracts and fractions were subjected to phytochemical screening and evaluation of total phenol and tannin contents. An HPLC-DAD and ultrastructural alterations analysis were performed. Terpenes and coumarins were detected in the cyclohexanic extract. Flavonoids and condensed tannins were present in the other extracts and fractions. The extracts with the highest contents of tannins, ethanol (EE), hydroalcoholic (HE), and aqueous fraction (AF) showed also the highest antimicrobial activity. The MIC values ranged from 64 to 526 µg/mL. The chromatographic fingerprints suggest the presence of astilbin and other flavonoids in EE and HE. Presence of the thick cell wall, undulating outer layer, abnormal septa, and leakage of the cytoplasmic contents and absence of cell wall and cell lyses were the main alterations observed on Staphylococcus aureus ATCC 33591 after treatment with the Hymenaea stigonocarpa hydroalcoholic extract. The presence of phenolic compounds like flavonoids and tannins is possibly the reason for the antimicrobial activity. PMID:24396311

Surface characterisation of ethylene propylene diene rubber upon exposure to aqueous acidic solution

NASA Astrophysics Data System (ADS)

Mitra, Susanta; Ghanbari-Siahkali, Afshin; Kingshott, Peter; Hvilsted, Søren; Almdal, Kristoffer

2006-07-01

Two types of pure ethylene propylene diene rubbers were exposed to two different acids for varying period of time. Surface characterisation was carried out using X-ray photoelectron spectroscopy (XPS). Two EPDM rubbers selected for this study were comparable in co-monomer compositions but significantly different with respect to molar mass and the presence of long chain branching. Both rubbers contained 5-ethylidene-2-norbornene (ENB) as diene. Solution cast films of pure EPDM samples were exposed in two different acidic solutions, viz. chromosulphuric (Cr (VI)/H 2SO 4) and sulphuric acid (H 2SO 4) (20%, v/v) at ambient temperature from 1 to 12 weeks. XPS analysis indicated that several oxygenated species were formed on the surface of both rubbers after exposure. It was postulated from the XPS analyses that both aqueous acidic solutions attacked the olefinic double bonds (C dbnd C) of ENB. Furthermore, 20% Cr (VI)/H 2SO 4 also attacked the allylic carbon-hydrogen (C sbnd H) bonds of ENB resulting in more oxygenated species on the surface compared to 20% H 2SO 4 under identical conditions. Cr (VI) in the 20% Cr (VI)/H 2SO 4 was found to play an important role in alteration of surface chemistry. Studies using a model system consisting of EPDM mixed with Cr (VI) and Cr (III) salts revealed that the change of oxidation state from Cr (VI) to Cr (III) as a consequence of direct involvement of Cr (VI) in the chemical alteration of EPDM surfaces. Interestingly, the presence of long chain branching and molar mass did not significantly influence the chemical processes owing to the acid treatment.

Low-temperature lithium diffusion in simulated high-level boroaluminosilicate nuclear waste glasses

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

Neeway, James J.; Kerisit, Sebastien N.; Gin, Stephane

2014-12-01

Ion exchange is recognized as an integral, if underrepresented, mechanism influencing glass corrosion. However, due to the formation of various alteration layers in the presence of water, it is difficult to conclusively deconvolute the mechanisms of ion exchange from other processes occurring simultaneously during corrosion. In this work, an operationally inert non-aqueous solution was used as an alkali source material to isolate ion exchange and study the solid-state diffusion of lithium. Specifically, the experiments involved contacting glass coupons relevant to the immobilization of high-level nuclear waste, SON68 and CJ-6, which contained Li in natural isotope abundance, with a non-aqueous solutionmore » of 6LiCl dissolved in dimethyl sulfoxide at 90 °C for various time periods. The depth profiles of major elements in the glass coupons were measured using time-of-flight secondary ion mass spectrometry (ToF-SIMS). Lithium interdiffusion coefficients, D Li, were then calculated based on the measured depth profiles. The results indicate that the penetration of 6Li is rapid in both glasses with the simplified CJ-6 glass (D 6Li ≈ 4.0-8.0 × 10 -21 m 2/s) exhibiting faster exchange than the more complex SON68 glass (D Li ≈ 2.0-4.0 × 10 -21 m 2/s). Additionally, sodium ions present in the glass were observed to participate in ion exchange reactions; however, different diffusion coefficients were necessary to fit the diffusion profiles of the two alkali ions. Implications of the diffusion coefficients obtained in the absence of alteration layers to the long-term performance of nuclear waste glasses in a geological repository system are also discussed.« less

Ceres Evolution: From Thermodynamic Modeling and Now Dawn Observation

NASA Astrophysics Data System (ADS)

McCord, T. B.; Combe, J. P.; Castillo, J. C.; Raymond, C. A.; De Sanctis, M. C.; Jaumann, R.; Ammannito, E.; Russell, C. T.

2015-12-01

Thermodynamic modeling indicated that Ceres has experienced planetary processes, including extensive melting of its ~25% water and differentiation, (McCord and Sotin, JGR, 2005; Castillo and McCord, Icarus, 2009). Early telescopic studies showed Ceres' surface to be spectrally similar to carboneous-chondrite-like material, i.e., aqueously altered silicates darkened by carbon, with a water-OH-related absorption near 3.06 µm. Later observations improved the spectra and suggested more specific interpretations: Structural water in clay minerals, phyllosilicates, perhaps ammoniated, iron-rich clays, carbonates, brucite, all implying extensive aqueous alteration, perhaps in the presence of CO2. Telescopic observations and thermodynamic models predicted Dawn would find a very different body compared to Vesta (e.g. McCord et al., SSR, 2011), as current Dawn observations are confirming. Ceres' original water ice should have melted early in its evolution, with the resulting differentiation and mineralization strongly affecting Ceres' composition, size and shape over time. The ocean should have become very salty and perhaps may still be liquid in places. The surface composition from telescopes seems to reflect this complex history. The mineralization with repeated mixing of the crust with the early liquid interior and with in-fall from space would create a complex surface that will present an interpretation challenge for Dawn. The Dawn spacecraft is currently collecting observations of Ceres' landforms, elemental and mineralogical/molecular composition and gravity field from orbit. Early results suggest a heavily cratered but distorted and lumpy body with features and composition consistent with internal activity, perhaps recent or current, associated with water and perhaps other volatiles. We will present and interpret the latest Dawn Ceres findings and how they affect our earlier understanding of Ceres evolution from modeling and telescope observations.

Crustal structure and igneous processes in a chondritic Io

NASA Technical Reports Server (NTRS)

Kargel, J. S.

1993-01-01

Liquid sulfur can form when metal-free C1 or C2 chondrites are heated. It may be obtained either by direct melting of native sulfur in disequilibrated C1 or C2 chondrites or by incongruent melting of pyrite and other sulfides in thermodynamically equilibrated rocks of the same composition. Hence, Lewis considered C2 chondrites to be the best meteoritic analog for Io's bulk composition. Metal-bearing C3 and ordinary chondrites are too chemically reduced to yield liquid sulfur and are not thought to represent plausible analogs of Io's bulk composition. An important aspect of Lewis' work is that CaSO4 and MgSO4 are predicted to be important in Io. Real C1 and C2 chondrites contain averages of, respectively, 11 percent and 3 percent by mass of salts (plus water of hydration). The most abundant chondritic salts are magnesium and calcium sulfates, but other important components include sulfates of sodium, potassium, and nickel and carbonates of magnesium, calcium, and iron. It is widely accepted that chondritic salts are formed by low-temperature aqueous alteration. Even if Io originally did not contain salts, it is likely that aqueous alteration would have yielded several percent sulfates and carbonates. In any event, Io probably contains sulfates and carbonates. This report presents the results of a model of differentiation of a simplified C2 chondrite-like composition that includes 1.92 percent MgSO4, 0.56 percent CaSO4, 0.53 percent CaCO3, and 0.094 percent elemental sulfur. The temperature of the model is gradually increased; ensuing fractional melting results in these components extruding or intruding at gravitationally stable levels in Io's crust. Relevant phase equilibria were reviewed. A deficiency of high-pressure phase equilibria renders the present model qualitative.

Aggregation and Deposition of C60 in Aqueous Systems

EPA Science Inventory

The extremely low water solubility of many fullerenes precludes aqueous solution processing for engineering applications and minimizes the potential for fullerene environmental effects in aqueous environments. However, studies have shown that C60 fullerene can form stable colloi...

Flame Suppression Agent, System and Uses

NASA Technical Reports Server (NTRS)

Parrish, Clyde F. (Inventor)

2013-01-01

Aqueous droplets encapsulated in a flame retardant polymer are useful in suppressing combustion. Upon exposure to a flame, the encapsulated aqueous droplets rupture and vaporize, removing heat and displacing oxygen to retard the combustion process. The polymer encapsulant, through decomposition, may further add free radicals to the combustion atmosphere, thereby further retarding the combustion process. The encapsulated aqueous droplets may be used as a replacement to halon, water mist and dry powder flame suppression systems.

Excavation of buried hydrated minerals on Mars by impact cratering? (Invited)

NASA Astrophysics Data System (ADS)

Carter, J.; Poulet, F.; Loizeau, D.; Bibring, J.

2010-12-01

Impact cratering is a key process when studying Mars’s past aqueous environments. It is a widespread and dynamic process which has been active throughout Mars’s history, especially during the Noachian era. Noachian-aged hydrated minerals have been reported on Mars (e.g. [1, 2]) and provide strong constrains on the alleged early wet Martian environment [3]. Our knowledge of this early wet environment will be greatly improved if we understand how hydrated minerals are formed, modified or destroyed by impact processes. One main consequence of impact cratering is the excavation of buried material. Excavated material is found in walls, ejecta and central uplifts in the case of large complex craters. It may originate from the deeply buried crust or subsurface, depending on crater size [4]. In this case craters act as natural boreholes that allow orbital spectroscopic inquiry of otherwise hidden material and is of great importance when investigating the aqueous alteration of Mars. This process has proven particularly useful when studying the northern crust of Mars which is covered by a thick mantling unit [5]. Large craters have penetrated the cover and exhumed buried hydrated crustal material, including the low-grade metamorphic mineral prehnite and there is evidence that the ancient crust has been altered by water down to kilometer depths, both in the northern plains and southern highlands [6]. Using the OMEGA and CRISM [7, 8] near-infrared hyperspectral instruments currently in orbit around Mars we have mapped surface exposures of hydrated minerals and found that many are associated with impact structures [9]. Here we report how detailed analysis of these sites reveal exposures of various hydrated minerals including phyllosilicates, zeolites and sulfates, associated with crater central uplifts, floors, walls, rims and ejecta. We focus on the heavily cratered Tyrrhena Terra region of Mars as well as the large northern plain craters. In both cases, excavation of buried, pre-existing phyllosilicates is thought to be the driving process. Other hydrated mineral formation pathways linked with impact cratering include impact-induced hydrothermal alteration [10-12], shock-induced and post-impact changes to mineral composition. [1]Poulet et al., Nature 438, 623 (2005). [2]Murchie et al., J. Geophys. Res. 114, E00D06 (2009). [3]Bibring et al., Science 312, 5772 (2006). [4]Baratoux et al., J. Geophys. Res. 112, E08S05 (2007). [5]Tanaka et al., J. Geophys. Res. 108, (E4), 8043 (2003). [6]Carter et al., Science 328, 1682 (2010). [7]Bibring et al., Eur. Space Agency Spec. Pub. 1240, 37 (2004). [8]Murchie et al., J. Geophys. Res. 114, E00D07 (2009). [9]Carter et al., Proc. Lunar Planet. Sci. Conf. 40, abstr. 2028 (2009). [10]Abramov and Kring, J. Geophys. Res. 110, (E12), E12S09 (2005). [11]Schwenzer and Kring, Geology 37, 1091 (2009). [12]Marzo et al., Icarus 208, 667-683 (2010).

Property Changes in Aqueous Solutions due to Surfactant Treatment of PCE: Implications to Geophysical Measurements

NASA Astrophysics Data System (ADS)

Werkema, D. D.

2007-12-01

Select physicochemical properties of aqueous solutions composed of surfactants, dye, and perchloroethylene (PCE) were evaluated through a response surface quadratic design model of experiment. Nine surfactants, which are conventionally used in the remediation of PCE, were evaluated with varying concentrations of PCE and indicator dyes in aqueous solutions. Two hundred forty experiments were performed using PCE as a numerical factor (coded A) from 0 to 200 parts per million (ppm), dye type (coded B) as a 3-level categorical factor, and surfactant type (coded C) as a 10-level categorical factor. Five responses were measured: temperature (°C), pH, conductivity (μS/cm), dissolved oxygen (DO, mg/L), and density (g/mL). Diagnostics proved a normally distributed predictable response for all measured responses except pH. The Box-Cox plot for transforms recommended a power transform for the conductivity response with lambda (λ) = 0.50, and for the DO response, λ =2.2. The overall mean of the temperature response proved to be a better predictor than the linear model. The conductivity response is best fitted with a linear model using significant coded terms B and C. Both DO and density also showed a linear model with coded terms A, B, and C for DO; and terms A and C for density. Some of the surfactant treatments of PCE significantly alter the conductivity, DO, and density of the aqueous solution. However, the magnitude of the density response is so small that it does not exceed the instrument tolerance. Results for the conductivity and DO responses provide predictive models for the surfactant treatment of PCE and may be useful in determining the potential for geophysically monitoring surfactant enhanced aquifer remediation (SEAR) of PCE. As the aqueous physicochemical properties change due to surfactant remediation efforts, so will the properties of the subsurface pore water which are influential factors in geophysical measurements. Geoelectrical methods are potentially the best suited to measure SEAR alterations in the subsurface because the conductivity of the pore fluid has the largest relative change. This research has provided predictive models for alterations in the physicochemical properties of the pore fluid to SEAR of PCE. Future investigations should address the contribution of the solid matrix in the subsurface and the solid-fluid interaction during SEAR of PCE contamination. Notice: Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy. Mention of trade names or commercial products does not constitute endorsement or recommendation by EPA for use.

CO2-rich geothermal areas in Iceland as natural analogues for geologic carbon sequestration

NASA Astrophysics Data System (ADS)

Thomas, D.; Maher, K.; Bird, D. K.; Brown, G. E.; Arnorsson, S.

2013-12-01

Geologic CO2 sequestration into mafic rocks via silicate mineral dissolution and carbonate precipitation has been suggested as a way to mitigate industrial CO2 emissions by storing CO2 in a stable form. Experimental observations of irreversible reaction of basalt with supercritical or gaseous and aqueous CO2 have resulted in carbonate precipitation, but there are no universal trends linking the extent of mineralization and type of reaction products to the bulk rock composition, glass percentage or mineralogy of the starting material. Additionally, concern exists that CO2 leakage from injection sites and migration through the subsurface may induce mineral dissolution and desorption of trace elements, potentially contaminating groundwater. This study investigates low-temperature (≤180°C) basaltic geothermal areas in Iceland with an anomalously high input of magmatic CO2 as natural analogues of the geochemical processes associated with the injection of CO2 into mafic rocks and possible leakage. Fluids that contain >4 mmol/kg total CO2 are common along the divergent Snæfellsnes Volcanic Zone in western Iceland and within the South Iceland Seismic Zone in southwest Iceland. The meteorically derived waters contain up to 80 mmol/kg dissolved inorganic carbonate (DIC). The aqueous concentration of major cations and trace elements is greater than that in Icelandic surface and groundwater and increases with DIC and decreasing pH. Concentrations of As and Ni in some samples are several times the World Health Organization (WHO) guidelines for safe drinking water. Thermodynamic modeling indicates that waters approach saturation with respect to calcite and/or aragonite, kaolinite and amorphous silica, and are undersaturated with respect to plagioclase feldspar, clinozoisite and Ca-zeolites. Petrographic study of drill cuttings from wells that intersect the CO2-rich areas indicates that the sites have undergone at least two stages of hydrothermal alteration: initial high-temperature and late stage low-temperature alteration. Imaging results from scanning electron microscopy show that calcite has replaced hydrothermally altered silicate minerals, such as albitic plagioclase. CO2-rich low-temperature fluids are not in equilibrium with correlative high-temperature hydrothermal mineral assemblages, indicating that the kinetics of mineral dissolution and secondary mineral precipitation, along with fluid residence times, are important controls on CO2 alteration and mineral formation at low temperatures. Our results have implications for predicting mineral product formation and trace element release during geologic carbon sequestration into hydrothermally altered basalts.

Compositional evolution of particle-phase reaction products and water in the heterogeneous OH oxidation of model aqueous organic aerosols

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

Chim, Man Mei; Cheng, Chiu Tung; Davies, James F.

Organic compounds present at or near the surface of aqueous droplets can be efficiently oxidized by gas-phase OH radicals, which alter the molecular distribution of the reaction products within the droplet. A change in aerosol composition affects the hygroscopicity and leads to a concomitant response in the equilibrium amount of particle-phase water. The variation in the aerosol water content affects the aerosol size and physicochemical properties, which in turn governs the oxidation kinetics and chemistry. To attain better knowledge of the compositional evolution of aqueous organic droplets during oxidation, this work investigates the heterogeneous OH-radical-initiated oxidation of aqueous methylsuccinic acid (C 5Hmore » 8O 4) droplets, a model compound for small branched dicarboxylic acids found in atmospheric aerosols, at a high relative humidity of 85 % through experimental and modeling approaches. Aerosol mass spectra measured by a soft atmospheric pressure ionization source (Direct Analysis in Real Time, DART) coupled with a high-resolution mass spectrometer reveal two major products: a five carbon atom (C 5) hydroxyl functionalization product (C 5H 8O 5) and a C 4 fragmentation product (C 4H 6O 3). These two products likely originate from the formation and subsequent reactions (intermolecular hydrogen abstraction and carbon–carbon bond scission) of tertiary alkoxy radicals resulting from the OH abstraction occurring at the methyl-substituted carbon site. Based on the identification of the reaction products, a kinetic model of oxidation (a two-product model) coupled with the Aerosol Inorganic–Organic Mixtures Functional groups Activity Coefficients (AIOMFAC) model is built to simulate the size and compositional changes of aqueous methylsuccinic acid droplets during oxidation. Model results show that at the maximum OH exposure, the droplets become slightly more hygroscopic after oxidation, as the mass fraction of water is predicted to increase from 0.362 to 0.424; however, the diameter of the droplets decreases by 6.1 %. This can be attributed to the formation of volatile fragmentation products that partition to the gas phase, leading to a net loss of organic species and associated particle-phase water, and thus a smaller droplet size. Overall, fragmentation and volatilization processes play a larger role than the functionalization process in determining the evolution of aerosol water content and droplet size at high-oxidation stages.« less

Compositional evolution of particle-phase reaction products and water in the heterogeneous OH oxidation of model aqueous organic aerosols

DOE PAGES

Chim, Man Mei; Cheng, Chiu Tung; Davies, James F.; ...

2017-12-05

Organic compounds present at or near the surface of aqueous droplets can be efficiently oxidized by gas-phase OH radicals, which alter the molecular distribution of the reaction products within the droplet. A change in aerosol composition affects the hygroscopicity and leads to a concomitant response in the equilibrium amount of particle-phase water. The variation in the aerosol water content affects the aerosol size and physicochemical properties, which in turn governs the oxidation kinetics and chemistry. To attain better knowledge of the compositional evolution of aqueous organic droplets during oxidation, this work investigates the heterogeneous OH-radical-initiated oxidation of aqueous methylsuccinic acid (C 5Hmore » 8O 4) droplets, a model compound for small branched dicarboxylic acids found in atmospheric aerosols, at a high relative humidity of 85 % through experimental and modeling approaches. Aerosol mass spectra measured by a soft atmospheric pressure ionization source (Direct Analysis in Real Time, DART) coupled with a high-resolution mass spectrometer reveal two major products: a five carbon atom (C 5) hydroxyl functionalization product (C 5H 8O 5) and a C 4 fragmentation product (C 4H 6O 3). These two products likely originate from the formation and subsequent reactions (intermolecular hydrogen abstraction and carbon–carbon bond scission) of tertiary alkoxy radicals resulting from the OH abstraction occurring at the methyl-substituted carbon site. Based on the identification of the reaction products, a kinetic model of oxidation (a two-product model) coupled with the Aerosol Inorganic–Organic Mixtures Functional groups Activity Coefficients (AIOMFAC) model is built to simulate the size and compositional changes of aqueous methylsuccinic acid droplets during oxidation. Model results show that at the maximum OH exposure, the droplets become slightly more hygroscopic after oxidation, as the mass fraction of water is predicted to increase from 0.362 to 0.424; however, the diameter of the droplets decreases by 6.1 %. This can be attributed to the formation of volatile fragmentation products that partition to the gas phase, leading to a net loss of organic species and associated particle-phase water, and thus a smaller droplet size. Overall, fragmentation and volatilization processes play a larger role than the functionalization process in determining the evolution of aerosol water content and droplet size at high-oxidation stages.« less

Experimental aqueous alteration of the Allende meteorite under oxidizing conditions: Constraints on asteroidal alteration

NASA Astrophysics Data System (ADS)

Jones, Catherine L.; Brearley, Adrian J.

2006-02-01

We have performed an experimental study of the aqueous alteration of the Allende CV3 carbonaceous chondrite under highly oxidizing conditions, in order to examine the alteration behavior of Allende's anhydrous mineralogy. The experiments were carried out at temperatures of 100, 150, and 200 °C, for time periods between 7 and 180 days, with water/rock ratios ranging from 1:1 to 9:1. Uncrushed cubes of Allende were used so that the spatial relationships between reactant and product phases could be examined in detail. Scanning electron microscope studies show that in all the experiments, even those of short duration (7 days), soluble salts of Ca and Mg (CaSO 4, CaCO 3, and MgSO 4) precipitated on the sample surface, indicating that these elements are rapidly mobilized during alteration. In addition, iron oxides and hydroxides formed on the sample surfaces. The sulfates, carbonates, and the majority of the iron-bearing secondary minerals are randomly distributed over the surface of samples. In some instances the iron oxides and hydroxides are constrained to the boundaries of altering mineral grains. Transmission electron microscope studies show that the FeO-rich olivine in the interior of the samples has altered to form interlayered serpentine/saponite and Fe-oxyhydroxides. The degree of alteration increases significantly with increasing water/rock ratio, and to a lesser extent with increasing duration of heating. The serpentine/saponite forms both by direct replacement of the olivine in crystallographically oriented intergrowths, and by recrystallization of an amorphous Si-rich phase that precipitates in pore space between the olivine grains. The alteration assemblage bears many similarities to those found in altered carbonaceous chondrites, although in detail there are important differences, which we attribute to (a) the relatively high temperatures of our experiments and (b) comparatively short reaction times compared with the natural examples. In terms of mineral assemblage, our experiments most closely resemble alteration in the CI chondrites, although the degree of alteration of our experiments is much lower. CI chondrites contain serpentine/saponite intergrowths and veins of Ca-sulfate and Ca-carbonate as well as the Fe-oxyhydroxide, ferrihydrite. However, the phyllosilicate phases formed in our experiments are somewhat coarser-grained than the finest phyllosilicate fraction present in CI chondrites, suggesting that alteration of the CI chondrites occurred at lower temperatures. In terms of mineral assemblage, our experiments also appear to come close to matching CR chondrites, although we infer that CR alteration probably occurred at temperatures <100 °C, based on the very fine-grained size of phyllosilicates in CR matrices.

Antihyperglycaemic effect of Mangifera indica in rat.

PubMed

Aderibigbe, A O; Emudianughe, T S; Lawal, B A

1999-09-01

The leaves of Mangifera indica are used as an antidiabetic agent in Nigerian folk medicine. To determine whether or not there is a scientific basis for this use, the effect of the aqueous extract of the leaves on blood glucose level was assessed in normoglycaemic, glucose - induced hyperglycaemic and streptozotocin (STZ)-induced diabetic rats. The aqueous extract given orally (1 g/kg) did not alter the blood glucose levels in either normoglycaemic or STZ-induced diabetic rats. In glucose - induced hyperglycaemia, however, antidiabetic activity was seen when the extract and glucose were administered simultaneously and also when the extract was given to the rats 60 min before the glucose. The hypoglycaemic effect of the aqueous extract was compared with that of an oral dose of chlorpropamide (200 mg/kg) under the same conditions. The results of this study indicate that the aqueous extract of the leaves of Mangifera indica possess hypoglycaemic activity. This action may be due to an intestinal reduction of the absorption of glucose. However, other different mechanisms of action cannot be excluded. Copyright 1999 John Wiley & Sons, Ltd.

RECOVERY OF ACTINIDES FROM AQUEOUS NITRIC ACID SOLUTIONS

DOEpatents

Ader, M.

1963-11-19

A process of recovering actinides is presented. Tetravalent actinides are extracted from rare earths in an aqueous nitric acid solution with a ketone and back-extracted from the ketone into an aqueous medium. The aqueous actinide solution thus obtained, prior to concentration by boiling, is sparged with steam to reduce its ketone to a maximum content of 3 grams per liter. (AEC)

Acute pulmonary pathology and sudden death in rats following the intravenous administration of the plasticizer, DI (2-ethylhexyl) phthalate, solubilized with Tween surfactants. [pathology of vinyl plastics poisoning

NASA Technical Reports Server (NTRS)

Schulz, C. O.; Rubin, R. J.; Hutchins, G. M.

1975-01-01

Intravenous administration of 200-300 mg/kg of di(2-ethylhexyl)phthalate (DEHP) solubilized in aqueous solutions of several Tween surfactants caused respiratory distress in rats. There was a dose-dependent lethality with death generally occurring within 90 minutes after injection. The lungs from DEHP:Tween treated animals were enlarged, generally darkened, and in some cases showed hemorrhagic congestion. Neither the overt symptoms nor the morphologic alterations resulting from DEHP:Tween administration could be reproduced by intravenous administration of aqueous Tween solutions alone. The absence of pulmonary abnormalities following the intravenous administration of DEHP as an aqueous emulsion given either alone or even as soon as 2 minutes after pretreatment with Tween 80, suggests that the specific in vivo interaction between DEHP and Tween surfactants depends on the prior formation of water-soluble micelles of DEHP.

Performance and histological responses of internal organs of broiler chickens fed raw, dehulled, and aqueous and dry-heated kidney bean meals.

PubMed

Emiola, I A; Ologhobo, A D; Gous, R M

2007-06-01

The objective of the present study was to investigate the effect of raw and differently processed [aqueous heating, dehulled, and dry heating (toasted)] kidney bean meals on the performance, weights, and histology of internal organs of broiler chicken. The feeding trial lasted for 56 d. Two hundred twenty-five 1-d-old broiler chicks (Anak strain) were used for the study. There were 5 treatment groups of 3 replicates with 15 birds per replicate. Raw and processed kidney bean meals were used to replace 50% protein supplied by soybean in the control diet. Data collected were used to evaluate feed intake, weight gain, and efficiency of feed utilization. The weights of liver, pancreas, kidney, heart, and lungs were also recorded and tissue samples of each collected for histological examination. Average daily food intake, average daily gain, and efficiency of feed utilization were influenced by the dietary treatments. Average daily food intake and average daily gain in birds fed the control diet and heat-treated kidney bean meals were similar and significantly (P<0.05) higher than those fed raw or dehulled meals. Feed conversion ratio was significantly (P<0.05) higher in birds fed raw or dehulled meals compared with those fed the control diet. The relative weight of the pancreas was significantly (P<0.05) increased as a result of acinar hypertrophy. The kidney had severe congestion of glomeruli and distention of the capillary vessels with numerous thrombi in birds fed raw and dehulled kidney bean meals. The weight of the liver was significantly (P<0.05) reduced in birds fed raw and dehulled meals, and the liver was characterized by marked coagulative necrosis and degeneration of the hepatocytes. The structural alterations were attributed to intake of trypsin inhibitors and haemagglutinins in the processed seeds. In conclusion, aqueous heated kidney bean meal can be used to replace 50% protein supplied by soybean meal in broiler starter and finisher diets without any adverse effect on the performance and the internal organs.

Transfer Kinetics at the Aqueous/Non-Aqueous Phase Liquid Interface. A Statistical Mechanic Approach

NASA Astrophysics Data System (ADS)

Doss, S. K.; Ezzedine, S.; Ezzedine, S.; Ziagos, J. P.; Hoffman, F.; Gelinas, R. J.

2001-05-01

Many modeling efforts in the literature use a first-order, linear-driving-force model to represent the chemical dissolution process at the non-aqueous/aqueous phase liquid (NAPL/APL) interface. In other words, NAPL to APL phase flux is assumed to be equal to the difference between the solubility limit and the "bulk aqueous solution" concentrations times a mass transfer coefficient. Under such assumptions, a few questions are raised: where, in relation to a region of pure NAPL, does the "bulk aqueous solution" regime begin and how does it behave? The answers are assumed to be associated with an arbitrary, predetermined boundary layer, which separates the NAPL from the surrounding solution. The mass transfer rate is considered to be, primarily, limited by diffusion of the component through the boundary layer. In fact, compositional models of interphase mass transfer usually assume that a local equilibrium is reached between phases. Representing mass flux as a rate-limiting process is equivalent to assuming diffusion through a stationary boundary layer with an instantaneous local equilibrium and linear concentration profile. Some environmental researchers have enjoyed success explaining their data using chemical engineering-based correlations. Correlations are strongly dependent on the experimental conditions employed. A universally applicable theory for NAPL dissolution in natural systems does not exist. These correlations are usually expressed in terms of the modified Sherwood number as a function of Reynolds, Peclet, and Schmidt numbers. The Sherwood number may be interpreted as the ratio between the grain size and the thickness of the Nernst stagnant film. In the present study, we show that transfer kinetics at the NAPL/APL interface under equilibrium conditions disagree with approaches based on the Nernst stagnant film concept. It is unclear whether local equilibrium assumptions used in current models are suitable for all situations.A statistical mechanic framework has been chosen to study the transfer kinetic processes at the microscale level. The rationale for our approach is based on both the activation energy of transfer of an ion and its velocity across the NAPL/APL interface. There are four major energies controlling the interfacial NAPL dissolution kinetics: (de)solvation energy, interfacial tension energy, electrostatic energy, and thermal fluctuation energy. Transfer of an ion across the NAPL/APL interface is accelerated by the viscous forces which can be described using the averaged Langevin master equation. The resulting energies and viscous forces were combined using the Boltzmann probability distribution. Asymptotic time limits of the resulting kinetics lead to instantaneous local equilibrium conditions that contradict the Nernst equilibrium equation. The NAPL/APL interface is not an ideal one: it does not conserve energy and heat. In our case the interface is treated as a thin film or slush zone that alters the thermodynamic variables. Such added zone, between the two phases, is itself a phase, and, therefore, the equilibrium does not occur between two phases but rather three. All these findings led us to develop a new non-linearly coupled flow and transport system of equations which is able to account for specific chemical dissolution processes and precludes the need for empirical mass-transfer parameters. Work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract W-7405-Eng-48.

Tuning Product Selectivity for Aqueous CO2 Reduction with a Mn(bipyridine)-pyrene Catalyst Immobilized on a Carbon Nanotube Electrode

PubMed Central

2017-01-01

The development of high-performance electrocatalytic systems for the controlled reduction of CO2 to value-added chemicals is a key goal in emerging renewable energy technologies. The lack of selective and scalable catalysts in aqueous solution currently hampers the implementation of such a process. Here, the assembly of a [MnBr(2,2′-bipyridine)(CO)3] complex anchored to a carbon nanotube electrode via a pyrene unit is reported. Immobilization of the molecular catalyst allows electrocatalytic reduction of CO2 under fully aqueous conditions with a catalytic onset overpotential of η = 360 mV, and controlled potential electrolysis generated more than 1000 turnovers at η = 550 mV. The product selectivity can be tuned by alteration of the catalyst loading on the nanotube surface. CO was observed as the main product at high catalyst loadings, whereas formate was the dominant CO2 reduction product at low catalyst loadings. Using UV–vis and surface-sensitive IR spectroelectrochemical techniques, two different intermediates were identified as responsible for the change in selectivity of the heterogenized Mn catalyst. The formation of a dimeric Mn0 species at higher surface loading was shown to preferentially lead to CO formation, whereas at lower surface loading the electrochemical generation of a monomeric Mn-hydride is suggested to greatly enhance the production of formate. These results emphasize the advantages of integrating molecular catalysts onto electrode surfaces for enhancing catalytic activity while allowing excellent control and a deeper understanding of the catalytic mechanisms. PMID:28885841

Electrolytic Plasma Processing for Sequential Cleaning and Coating Deposition for Cadmium Plating Replacement

DTIC Science & Technology

2008-08-01

deposit Al coatings or ZnAl alloys from aqueous solution. Unfortunately this proved impossible, producing only Al hydroxides and oxides, which are... deposited by normal aqueous electroplating methods. A great deal of effort was expended on attempts to produce metallic Al alloys , but no satisfactory... process . If an Al -bearing salt were soluble in a non- aqueous fluid that did not need an enclosure, then it might be possible to deposit Al coatings

Organic-aqueous crossover coating process for the desmopressin orally disintegrating microparticles.

PubMed

Kim, Ju-Young; Hwang, Kyu-Mok; Park, Chun-Woong; Rhee, Yun-Seok; Park, Eun-Seok

2015-02-01

The purpose of the present study was to prepare desmopressin orally disintegrating microparticles (ODMs) using organic-aqueous crossover coating process which featured an organic sub-coating followed by an aqueous active coating. Sucrose beads and hydroxypropyl cellulose (HPC) were used as inert cores and a coating material, respectively. Characterizations including size distribution analysis, in-vitro release studies and in-vitro disintegration studies were performed. A pharmacokinetic study of the ODMs was also conducted in eight beagle dogs. It was found that sucrose beads should be coated using organic solvents to preserve their original morphology. For the active coating, the aqueous coating solution should be used for drug stability. When sucrose beads were coated using organic-aqueous crossover coating process, double-layer ODMs with round shapes were produced with detectable impurities below limit of US Pharmacopeia. The median size of ODMs was 195.6 μm, which was considered small enough for a good mouthfeel. The ODMs dissolved in artificial saliva within 15 s because of hydrophilic materials including sucrose and HPC in the ODMs. Because of its fast-dissolving properties, 100% release of the drug was reached within 5 min. Pharmacokinetic parameters including Cmax and AUC24 indicated bioequivalence of the ODMs and the conventional immediate release tablets. Therefore, by using the organic-aqueous crossover coating process, double-layer ODMs were successively prepared with small size, round shapes and good drug stability.

Presolar silicates in the matrix and fine-grained rims around chondrules in primitive CO3.0 chondrites: Evidence for pre-accretionary aqueous alteration of the rims in the solar nebula

NASA Astrophysics Data System (ADS)

Haenecour, Pierre; Floss, Christine; Zega, Thomas J.; Croat, Thomas K.; Wang, Alian; Jolliff, Bradley L.; Carpenter, Paul

2018-01-01

To investigate the origin of fine-grained rims around chondrules (FGRs), we compared presolar grain abundances, elemental compositions and mineralogies in fine-grained interstitial matrix material and individual FGRs in the primitive CO3.0 chondrites Allan Hills A77307, LaPaz Icefield 031117 and Dominion Range 08006. The observation of similar overall O-anomalous (∼155 ppm) and C-anomalous grain abundances (∼40 ppm) in all three CO3.0 chondrites suggests that they all accreted from a nebular reservoir with similar presolar grain abundances. The presence of presolar silicate grains in FGRs combined with the observation of similar estimated porosity between interstitial matrix regions and FGRs in LAP 031117 and ALHA77307, as well as the identification of a composite FGR (a small rimmed chondrule within a larger chondrule rim) in ALHA77307, all provide evidence for a formation of FGRs by accretion of dust grains onto freely-floating chondrules in the solar nebula before their aggregation into their parent body asteroids. Our study also shows systematically lower abundances of presolar silicate grains in the FGRs than in the matrix regions of CO3 chondrites, while the abundances of SiC grains are the same in all areas, within errors. This trend differs from CR2 chondrites in which the presolar silicate abundances are higher in the FGRs than in the matrix, but similar to each other within 2σ errors. This observation combined with the identification of localized (micrometer-scaled) aqueous alteration in a FGR of LAP 031117 suggests that the lower abundance of presolar silicates in FGRs reflects pre-accretionary aqueous alteration of the fine-grained material in the FGRs. This pre-accretionary alteration could be due to either hydration and heating of freely floating rimmed chondrules in icy regions of the solar nebula or melted water ice associated with 26Al-related heating inside precursor planetesimals, followed by aggregation of FGRs into the CO chondrite parent-body.

Engineered metal based nanomaterials in aqueous environments: Interactions, transformations and implications

NASA Astrophysics Data System (ADS)

Mudunkotuwa, Imali Ama

Nanoscience and nanotechnology offer potential routes towards addressing critical issues such as clean and sustainable energy, environmental protection and human health. Specifically, metal and metal oxide nanomaterials are found in a wide range of applications and therefore hold a greater potential of possible release into the environment or for the human to be exposed. Understanding the aqueous phase behavior of metal and metal oxide nanomaterials is a key factor in the safe design of these materials because their interactions with living systems are always mediated through the aqueous phase. Broadly the transformations in the aqueous phase can be classified as dissolution, aggregation and adsorption which are dependent and linked processes to one another. The complexity of these processes at the liquid-solid interface has therefore been one of the grand challenges that has persisted since the beginning of nanotechnology. Although classical models provide guidance for understanding dissolution and aggregation of nanoparticles in water, there are many uncertainties associated with the recent findings. This is often due to a lack of fundamental knowledge of the surface structure and surface energetics for very small particles. Therefore currently the environmental health and safety studies related to nanomaterials are more focused on understanding the surface chemistry that governs the overall processes in the liquid-solid interfacial region at the molecular level. The metal based nanomaterials focused on in this dissertation include TiO2, ZnO, Cu and CuO. These are among the most heavily used in a number of applications ranging from uses in the construction industry to cosmetic formulation. Therefore they are produced in large scale and have been detected in the environment. There is debate within the scientific community related to their safety as a result of the lack of understanding on the surface interactions that arise from the detailed nature of the surfaces. Specifically, the interactions of these metal and metal oxide nanoparticles with environmental and biological ligands in the solutions have demonstrated dramatic alterations in their aqueous phase behavior in terms of dissolution and aggregation. Dissolution and aggregation are among the determining factors of nanoparticle uptake and toxicity. Furthermore, solution conditions such as ionic strength and pH can act as controlling parameters for surface ligand adsorption while adsorbed ligands themselves undergo surface induced structural and conformational changes. Because, nanomaterials in both the environment and in biological systems are subjected to a wide range of matrix conditions they are in fact dynamic and not static entities. Thus monitoring and tracking these nanomaterials in real systems can be extremely challenging which requires a thorough understanding of the surface chemistry governing their transformations. The work presented in this dissertation attempts to bridge the gap between the dynamic processing of these nanomaterials, the details of the molecular level processes that occur at the liquid-solid interfacial region and potential environmental and biological interactions. Extensive nanomaterial characterization is an integral part of these investigations and all the materials presented here are thoroughly analyzed for particle size, shape, surface area, bulk and surface compositions. Detailed spectroscopic analysis was used to acquire molecular information of the processes in the liquid-solid interfacial region and the outcomes are linked with the macroscopic analysis with the aid of dynamic and static light scattering techniques. Furthermore, emphasis is given to the size dependent behavior and theoretical modeling is adapted giving careful consideration to the details of the physicochemical characterization and molecular information unique to the nanomaterials.

Aqueous-Processed Inorganic Thin-Film Solar Cells Based on CdSe(x)Te(1-x) Nanocrystals: The Impact of Composition on Photovoltaic Performance.

PubMed

Zeng, Qingsen; Chen, Zhaolai; Zhao, Yue; Du, Xiaohang; Liu, Fangyuan; Jin, Gan; Dong, Fengxia; Zhang, Hao; Yang, Bai

2015-10-21

Aqueous processed nanocrystal (NC) solar cells are attractive due to their environmental friendliness and cost effectiveness. Controlling the bandgap of absorbing layers is critical for achieving high efficiency for single and multijunction solar cells. Herein, we tune the bandgap of CdTe through the incorporation of Se via aqueous process. The photovoltaic performance of aqueous CdSexTe1-x NCs is systematically investigated, and the impacts of charge generation, transport, and injection on device performance for different compositions are deeply discussed. We discover that the performance degrades with the increasing Se content from CdTe to CdSe. This is mainly ascribed to the lower conduction band (CB) of CdSexTe1-x with higher Se content, which reduces the driving force for electron injection into TiO2. Finally, the performance is improved by mixing CdSexTe1-x NCs with conjugated polymer poly(p-phenylenevinylene) (PPV), and power conversion efficiency (PCE) of 3.35% is achieved based on ternary NCs. This work may provide some information to further optimize the aqueous-processed NC and hybrid solar cells.

What Hayabusa2 Will Find at Asteroid Ryugu, and What It Will Reveal About the Source of Earth's Water

NASA Technical Reports Server (NTRS)

Zolensky, Michael; Martinez, James E.

2017-01-01

Water-rich carbonaceous chondrites contain evidence of aqueous alteration in the early solar system. To see this one must look carefully at the meteorites, and see past the later alteration which has generally obscured mineral textures. We suggest that these materials will dominate, be detectable, and be sampled on the surfaces of C-class asteroids, initially by the Hayabusa2 spacecraft. Thus, hydrous samples returned by this mission will help to reveal the source of water on earth.

Fluorophotometric determination of aqueous humor flow rates in red-tailed hawks (Buteo jamaicensis).

PubMed

Jones, Michael P; Ward, Daniel A

2012-04-01

To determine aqueous humor flow rate (AHFR) in an avian species by use of anterior segment fluorophotometry. 9 healthy red-tailed hawks (Buteo jamaicensis; 4 males and 5 females) that ranged from 8 months to 8 years of age. A protocol was developed for fluorophotometric determination of AHFR. Topical administration of 10% fluorescein was used to load the corneas, and corneal and aqueous humor fluorescein concentrations were measured approximately 5, 6.5, and 8 hours later. Concentration-versus-time plots were generated, and slopes and cornea-to-aqueous humor concentration ratios from these plots were used to manually calculate flow rates. Mean ± SD AHFRs for the right eye, left eye, and both eyes were 3.17 ± 1.36 μL/min (range, 1.67 to 6.21 μL/min), 2.86 ± 0.88 μL/min (range, 2.04 to 4.30 μL/min), and 2.90 ± 0.90 μL/min (range, 1.67 to 4.42 μL/min), respectively. The AHFRs were similar for right and left eyes. These flow rates represented a mean aqueous humor transfer coefficient of 0.0082/min, which is similar to that of mammalian species. The AHFR in red-tailed hawks was similar to that of most mammalian species, and the fractional egress was almost identical to that of other species. This information will allow a greater understanding of aqueous humor flow in avian eyes, which is crucial when evaluating diseases that affect avian eyes as well as medications that alter aqueous humor flow.

Alterations of thorium oxalate morphology by changing elementary precipitation conditions

NASA Astrophysics Data System (ADS)

Tyrpekl, V.; Beliš, M.; Wangle, T.; Vleugels, J.; Verwerft, M.

2017-09-01

Oxalates of actinide elements are widely used in research and industry mainly due to their low solubility in aqueous solution and easy conversion to oxide. Although thorium oxide is worldwide mostly produced by the oxalate precipitation and conversion route, the powder morphology obtained through this process is known to inhibit the packing and sintering step of the pellet production. The presented work investigates the effects of oxalate precipitation conditions on the final powder morphology. Among the precipitation conditions considered are: pH of the thorium feed solution, concentration, temperature and the order of addition (thorium solution in oxalic acid solution and vice versa) known as reverse/direct strike. Herein, we show that the morphology of the final oxalate depends significantly on the above mentioned precipitation parameters.

Sulfates on Mars as Markers of Aqueous Processes: An Integrated Multidisciplinary Study of Minerals, Mars Analog sites and Recent Mission Data

NASA Technical Reports Server (NTRS)

Bishop, J. L.; Lane, M. D.; Dyar, M. D.; Brown, A. J.; Parente, M.

2006-01-01

Our analyses of sulfate minerals, analog sites, and Martian spectra and spectral images is focused on characterization of the Martian surface and in particular identification of aqueous processes there.

Treatment of aqueous phase of bio-oil by granular activated carbon and evaluation of biogas production.

PubMed

Shanmugam, Saravanan R; Adhikari, Sushil; Wang, Zhouhang; Shakya, Rajdeep

2017-01-01

Hydrothermal liquefaction of wet biomass such as algae is a promising thermochemical process for the production of bio-oil. Bio-oil aqueous phase generated during liquefaction process is rich in complex organics and can be utilized for biogas production following its pre-treatment with granular activated carbon. In our study, use of 30% activated carbon resulted in higher chemical oxygen demand (COD) reduction (53±0.3%) from aqueous phase. Higher CH 4 production (84±12mL/gCOD) was also observed in 30% carbon-treated aqueous phase fed cultures, whereas only 32±6mLCH 4 /gCOD was observed in control (non-carbon treated) cultures. The results from this study indicate that almost 67±0.3% initial COD of aqueous phase can be reduced using a combination of both carbon treatment and biogas production. This study shows that aqueous phase can be utilized for CH 4 production. Copyright © 2016 Elsevier Ltd. All rights reserved.

Mineralogy of dark asteroids: Detection of phyllosilicate features in the mid-infrared

NASA Astrophysics Data System (ADS)

McAdam, Margaret; Sunshine , Jessica Sunshine M.; Kelley, Michael S.

2014-11-01

Dark asteroids (C- and related types) have been shown to have phyllosilicates on their surfaces by the presence of the 0.7-µm charge transfer band in the visible/near-infrared (VIS/NIR) spectral region (e.g. [1], [2]). Observations of asteroids in the 2.5-5-µm have also indicated the presence of water [3, 4] and phyllosilicates [5, 6]. Phyllosilicates also have spectral features in the 8-30-µm [7]. The results of a coordinated spectral-mineralogical study of aqueously altered meteorites [8] can be used to both remotely identify the presence of aqueous alteration and determine the degree of alteration on asteroids. Two main regions have strong features related to the mineralogy and degree of alteration: the 10-13-µm and the 16-25-µm region. Alteration features change continuously in these regions between less 60%) and highly 90%) altered meteorites. These features have been identified in the spectra of some dark asteroids [8, 9, 10]. Additionally, no trends are found between 0.7-µm charge transfer band and degree of alteration. While all meteorites with a 0.7-µm band have phyllosilicates, the absence of a 0.7-µm band is not indicative of the absence of alteration. Altered meteorites always exhibit MIR features that are directly related to their degree of alteration whether or not they have a 0.7-µm band. Here, we present preliminary results of a survey of archived Spitzer Space Telescope data of asteroids in the 10-13-µm region and the 16-25-µm region (where data is available) including comparisons to published VIS/NIR spectra of the same dark asteroids without VIS/NIR features. Possible effects in comparing laboratory measurements of meteorite powders under ambient conditions to telescopic spectra of asteroid regoliths are considered. [1] Vilas and Gaffey, (1989) Nature, 246, 790-792. [2] Barucci et al (1998) Icarus, 132, 388-396. [3] Campins et al., (2010), Nature Letters, 464, 1320-1321. [4] Rivkin & Emery (2010) Nature Letters, 464, 1322-1323. [5] Hargrove, et al. (2012), Icarus, 221, 453-455. [6] Takir and Emery (2012) Icarus, 219, 641-654. [7] Calvin & King, (1997), Met. & Plan. Sci., 32, 693-701. [8] McAdam et al, Icarus, in review. [9] McAdam, et al (2013) DPS abs. [10] McAdam et al, ACM abs.

Hydrothermally-altered dacite terrains in the Methana peninsula Greece: Relevance to Mars

NASA Astrophysics Data System (ADS)

Cloutis, Edward A.; Jonatanson, Victoria; Bandfield, Joshua L.; Amador, Elena S.; Rivera-Hernández, Frances; Mann, P.; Mertzman, Stanley A.

2017-04-01

Dacitic rocks, often indicative of crustal recycling on Earth, have been identified in some regions on Mars, as have possible hydrothermally/aqueously-altered dacites. To enable more robust identification of unaltered and altered dacites on Mars and other planetary bodies, we undertook a spectroscopic-structural-compositional study of altered and unaltered dacites from a dacitic volcanic region in Methana, Greece. Dacites erupted in this region range from fresh to pervasively hydrothermally altered, resulting in friable, Si-enriched products, as well as fumarolic deposition of Si and S-rich precipitates. Spectrally, fresh dacites are unremarkable in the 0.35-2.5 μm region with low, generally flat, reflectance and few, if any, absorption bands. Dacite infrared spectra exhibit Si-O absorption features in the 8-10 μm region (which are characteristic of Si-bearing rocks, in general). With increasing alteration, reflectance over the 0.35-2.5 μm range increases, absorption bands in the 1.4 and 1.9 μm region, associated with H2O/OH, and in the 2.2-2.3 μm region, associated with SiOH, become deeper, Fe3+-associated absorption bands in the 0.43 and 0.9 μm region appear, and the Christiansen feature near 8 μm moves to shorter wavelengths. Silica-rich coatings appear to be spectrally indistinguishable from Si-rich alteration. Alteration-formed sulfates may be detectable by the presence of diagnostic absorption features in the 0.35-2.5 μm region. Spectral similarities between different poorly crystalline high-Si phases make it difficult to uniquely determine the processes that formed high-Si surfaces that have been identified on Mars. However, the samples described here show a variety of spectral features that correspond to variable amounts of alteration. We find a similar range of spectral features, likely due to similar phases, on Mars, perhaps indicating a similar range of alteration environments. Comparison of laboratory spectra to Mars observational data also suggests that the major Si-rich regions likely consist of assemblages that more mineralogically complex than those included in this study.

Coarse muscovite veins and alteration deep in the Yerington batholith, Nevada: insights into fluid exsolution in the roots of porphyry copper systems

NASA Astrophysics Data System (ADS)

Runyon, Simone E.; Steele-MacInnis, Matthew; Seedorff, Eric; Lecumberri-Sanchez, Pilar; Mazdab, Frank K.

2017-04-01

Veins and pervasive wall-rock alteration composed of coarse muscovite±quartz±pyrite are documented for the first time in a porphyritic granite at Luhr Hill in the Yerington District, Nevada. Coarse muscovite at Luhr Hill occurs at paleodepths of 6-7 km in the roots of a porphyry copper system and crops out on the scale of tens to hundreds of meters, surrounded by rock that is unaltered or variably altered to sodic-calcic assemblages. Coarse muscovite veins exhibit a consistent orientation, subvertical and N-S striking, which structurally restores to subhorizontal at the time of formation. Along strike, coarse muscovite veins swell from distal, millimeter-thick muscovite-only veinlets to proximal, centimeter-thick quartz-sulfide-bearing muscovite veins. Crosscutting relationships between coarse muscovite veins, pegmatite dikes, and sodic-calcic veins indicate that muscovite veins are late-stage magmatic-hydrothermal features predating final solidification of the Luhr Hill porphyritic granite. Fluid inclusions in the muscovite-quartz veins are high-density aqueous inclusions of 3-9 wt% NaCl eq. and <1 mol% CO2 that homogenize between 150 and 200 °C, similar to fluid inclusions from greisen veins in Sn-W-Mo vein systems. Our results indicate that muscovite-forming fluids at Luhr Hill were mildly acidic, of low to moderate salinity and sulfur content and low CO2 content, and that muscovite in deep veins and alteration differs in texture, composition, and process of formation from sericite at shallower levels of the hydrothermal system. Although the definition of greisen is controversial, we suggest that coarse muscovite alteration is more similar to alteration in greisen-type Sn-W-Mo districts worldwide than to sericitic alteration at higher levels of porphyry copper systems. The fluids that form coarse muscovite veins and alteration in the roots of porphyry copper systems are distinct from fluids that formed copper ore or widespread, shallower, acidic alteration. We propose that this style of veins and alteration at Luhr Hill represents degassing of moderate volumes of overpressured hydrothermal fluid during late crystallization of deep levels of the Yerington batholith.

Development of environmentally conscious cleaning process for leadless chip carrier assemblies. Final report

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

Adams, B.E.

1995-04-01

A cross-functional team of process, product, quality, material, and design lab engineers was assembled to develop an environmentally friendly cleaning process for leadless chip carrier assemblies (LCCAs). Using flush and filter testing, Auger surface analysis, GC-Mass spectrophotometry, production yield results, and electrical testing results over an extended testing period, the team developed an aqueous cleaning process for LCCAs. The aqueous process replaced the Freon vapor degreasing/ultrasonic rinse process.

Process for recovering pertechnetate ions from an aqueous solution also containing other ions

DOEpatents

Rogers, Robin; Horwitz, E. Philip; Bond, Andrew H.

1997-01-01

A solid/liquid process for the separation and recovery of TcO.sub.4.sup.-1 ions from an aqueous solution is disclosed. The solid support comprises separation particles having surface-bonded poly(ethylene glycol) groups; whereas the aqueous solution from which the TcO.sub.4.sup.-1 ions are separated contains a poly(ethylene glycol) liquid/liquid biphase-forming amount of a dissolved salt. A solid/liquid phase admixture of separation particles containing bound TcO.sub.4.sup.-1 ions in such an aqueous solution that is free from MoO.sub.4.sup.-2 ions is also contemplated, as is a chromatography apparatus containing that solid/liquid phase admixture.

The Effect of Shock on the Amorphous Component in Altered Basalt

NASA Technical Reports Server (NTRS)

Eckley, S. A.; Wright, S. P.; Rampe, E. B.; Niles, P. B.

2017-01-01

Investigation of the geochemical and mineralogical composition of the Martian surface provides insight into the geologic history of the predominantly basaltic crust. The Chemistry and Mineralogy (CheMin) instrument onboard the Curiosity rover has returned the first X-Ray diffraction data from the Martian surface. However, large proportions (27 +/- 14 with some estimates as high as 50 weight percentage) of an amorphous component have been reported. As a remedy to this problem, mass balance equations using geochemistry, volatile chemistry, and mineralogy have been employed to constrain the geochemistry of the amorphous component. However, "the nature and number of amorphous phases that constitute the amorphous component is not unequivocally known". Multiple hypotheses have been proposed to explain the origin of this amorphous component: Allophane (Al2O); Basaltic glass (Volcanic and impact); Palagonite (Altered basaltic glass); Hisingerite (Fe (sup 3 plus)-bearing phyllosilicate); S/Cl-rich component (sulfates and/or akaganeite); Nanophase ferric oxide component (npOx). Establishing a multi-phase amorphous component from a basaltic precursor that has undergone physical and chemical weathering within geochemical constraints is of paramount importance to better understand the composition of a large portion of the Martian surface (up to 50 weight percentage). Shocked basalts from Lonar Crater in India are valuable analogs for the Martian surface because it is a well-preserved impact crater in a basaltic target. Having undergone pre- and post-shock aqueous alteration, these rocks provide crucial data regarding the effect of shock on the amorphous component in altered basalt. By conducting mass balance equations similar to what has been performed for Gale crater materials, we attempt to calculate the geochemistry of the amorphous component in altered basalts ranging from unshocked to Class 5 (Table 1). This has the potential to reveal the nature and origin (i.e. primary igneous, shock metamorphic, and/or aqueous alteration occurring before or after the impact event) of the amorphous component in shocked basalt with the goal of unravelling the history of the Martian surface.

Aqueous biphasic extraction process with pH and particle control

DOEpatents

Chaiko, David J.; Mensah-Biney, R.

1995-01-01

A process for aqueous biphasic extraction of metallic oxides and the like from substances containing silica. Control of media pH enables efficient and effective partition of mixture components. The inventive method may be employed to remove excess silica from kaolin clay.

Hydrothermal alteration and diagenesis of terrestrial lacustrine pillow basalts: Coordination of hyperspectral imaging with laboratory measurements

USGS Publications Warehouse

Greenberger, Rebecca N; Mustard, John F; Cloutis, Edward A; Mann, Paul; Wilson, Janette H.; Flemming, Roberta L; Robertson, Kevin; Salvatore, Mark R; Edwards, Christopher

2015-01-01

The phases identified in the sample are albite, large iron oxides, and titanite throughout; calcite in vesicles; calcic clinopyroxene, aegirine, and Fe/Mg-bearing clay in the rind; and fine-grained hematite and pyroxenes in the interior. Using imaging spectroscopy, the chemistry and mineralogy results extend to the hand sample and larger outcrop. From all of the analyses, we suggest that the pillow basalts were altered initially after emplacement, either by heated lake water or magmatic fluids, at temperatures of at least 400-600°C, and the calcic clinopyroxenes and aegirine identified in the rind are a preserved record of that alteration. As the hydrothermal system cooled to slightly lower temperatures, clays formed in the rind, and, during this alteration, the sample oxidized to form hematite in the matrix of the interior and Fe3+ in the pyroxenes in the rind. During the waning stages of the hydrothermal system, calcite precipitated in vesicles within the rind. Later, diagenetic processes albitized the sample, with albite replacing plagioclase, lining vesicles, and accreting onto the exterior of the sample. This albitization or Na-metasomatism occurred when the lake within the Hartford Basin evaporated during a drier past climatic era, resulting in Na-rich brines. As Ca-rich plagioclase altered to albite, Ca was released into solution, eventually precipitating as calcite in previously-unfilled vesicles, dominantly in the interior of the pillow. Coordinated analyses of this sample permit identification of the alteration phases and help synthesize the aqueous history of pillow lavas of the Talcott formation. These results are also relevant to Mars, where volcanically-resurfaced open basin lakes have been found, and this Hartford Basin outcrop may be a valuable analog for any potential volcano-lacustrine interactions. The results can also help to inform the utility and optimization of potentially complementary, synergistic, and uniquely-suited techniques for characterization of hydrothermally-altered terrains.

Investigation of the Blood Glucose Lowering Potential of the Jamaican Momordica charantia (Cerasee) Fruit in Sprague-Dawley Rats

PubMed Central

Burnett, A; McKoy, M-L; Singh, P

2015-01-01

ABSTRACT The Momordica charantia (MC) fruit has been documented to possess antidiabetic properties. However, these studies were not without controversy surrounding the blood glucose-lowering ability and the mechanism of action in diabetes therapy. In an effort to evaluate such claims in the Jamaican MC species known as cerasee, aqueous extracts of the unripe fruit were studied in normal and diabetic rats. Normal male Sprague-Dawley rats were divided into groups (n = 6) orally administered distilled water, 10% dimethyl sulfoxide (DMSO) solution, the aqueous extract (400 mg/kg body weight) and glibenclamide (15 mg/kg body weight), respectively prior to assessment of fasting blood glucose (FBG) concentration. The oral glucose tolerance test (OGTT) was conducted in normoglycaemic rats orally administered distilled water, 10% DMSO solution, glibenclamide (15 mg/kg body weight) or aqueous extracts of the fruit (200 and 400 mg/kg body weight). Blood glucose concentration was also monitored in streptozotocin-induced diabetic rats administered the aqueous extract (250 mg/kg body weight) or water vehicle after an overnight fast. The aqueous extracts showed no hypoglycaemic or antidiabetic activity. However, the administration of the aqueous extracts (200 and 400 mg/kg body weight) resulted in significant improvement in glucose tolerance of glucose-primed normoglycaemic rats during the OGTT. These data suggest that the glucose-lowering mechanism of the Jamaican MC fruit species likely involves altered glucose absorption across the gastrointestinal tract. PMID:26624580

Water-soluble polymers for recovery of metal ions from aqueous streams

DOEpatents

Smith, Barbara F.; Robison, Thomas W.

1998-01-01

A process of selectively separating a target metal contained in an aqueous solution by contacting the aqueous solution containing a target metal with an aqueous solution including a water-soluble polymer capable of binding with the target metal for sufficient time whereby a water-soluble polymer-target metal complex is formed, and, separating the solution including the water-soluble polymer-target metal complex from the solution is disclosed.

Insights into Aqueous-phase processing through Comparison of the Organic Chemical Composition of Atmospheric Particles and Cloud Water in the Southeast United States

NASA Astrophysics Data System (ADS)

Boone, E.; Laskin, J.; Laskin, A.; Wirth, C.; Shepson, P. B.; Stirm, B. H.; Pratt, K.

2014-12-01

Organic compounds comprise a significant mass fraction of submicron atmospheric particles with considerable contribution from secondary organic aerosol (SOA), a large fraction of which is formed from the oxidation of biogenic volatile organic compounds. Aqueous-phase reactions in particles and cloud droplets are suggested to increase SOA mass and change the chemical composition the particles following cloud evaporation. Aqueous-phase processing may also explain discrepancies between measurements and models. To gain a better understanding of these processes, cloud water and below-cloud atmospheric particles were collected onboard a research aircraft during the Southeast Oxidants and Aerosol Study (SOAS) over Alabama in June 2013. Nanospray desorption electrospray ionization (nano-DESI) and direct electrospray ionization (ESI) coupled with high resolution mass spectrometry were utilized to compare the organic molecular composition of the particle and cloud water samples, respectively. Several hundred unique compounds have been identified in the particle and cloud water samples, allowing possible aqueous-phase reactions to be examined. Hydrolysis of organosulfate compounds, aqueous-phase formation of nitrogen-containing compounds, and possible fragmentation of oligomeric compounds will be discussed, with comparisons to previous laboratory studies. This study provides insights into aqueous-phase reactions in ambient cloud droplets.

Trivalent Lanthanide/Actinide Separation Using Aqueous-Modified TALSPEAK Chemistry

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

Travis S. Grimes; Richard D. Tillotson; Leigh R. Martin

TALSPEAK is a liquid/liquid extraction process designed to separate trivalent lanthanides (Ln3+) from minor actinides (MAs) Am3+ and Cm3+. Traditional TALSPEAK organic phase is comprised of a monoacidic dialkyl bis(2-ethylhexyl)phosphoric acid extractant (HDEHP) in diisopropyl benzene (DIPB). The aqueous phase contains a soluble aminopolycarboxylate diethylenetriamine-N,N,N’,N”,N”-pentaacetic acid (DTPA) in a concentrated (1.0-2.0 M) lactic acid (HL) buffer with the aqueous acidity typically adjusted to pH 3.0. TALSPEAK balances the selective complexation of the actinides by DTPA against the electrostatic attraction of the lanthanides by the HDEHP extractant to achieve the desired trivalent lanthanide/actinide group separation. Although TALSPEAK is considered a successfulmore » separations scheme, recent fundamental studies have highlighted complex chemical interactions occurring in the aqueous and organic phases during the extraction process. Previous attempts to model the system have shown thermodynamic models do not accurately predict the observed extraction trends in the p[H+] range 2.5-4.8. In this study, the aqueous phase is modified by replacing the lactic acid buffer with a variety of simple and longer-chain amino acid buffers. The results show successful trivalent lanthanide/actinide group separation with the aqueous-modified TALSPEAK process at pH 2. The amino acid buffer concentrations were reduced to 0.5 M (at pH 2) and separations were performed without any effect on phase transfer kinetics. Successful modeling of the aqueous-modified TALSPEAK process (p[H+] 1.6-3.1) using a simplified thermodynamic model and an internally consistent set of thermodynamic data is presented.« less

Oxygen, Magnesium, and Aluminum Isotopes in the Ivuna CAI: Re-Examining High-Temperature Fractionations in CI Chondrites

NASA Technical Reports Server (NTRS)

Frank, D. R.; Huss, G. R.; Nagashima, K.; Zolensky, M. E.; Le, L.

2017-01-01

CI chondrites are thought to approximate the bulk solar system composition since they closely match the composition of the solar photosphere. Thus, chemical differences between a planetary object and the CI composition are interpreted to result from fractionations of a CI starting composition. This interpretation is often made despite the secondary mineralogy of CI chondrites, which resulted from low-T aqueous alteration on the parent asteroid(s). Prevalent alteration and the relatively large uncertainties in the photospheric abundances (approx. +/-5-10%) permit chemical fractionation of CI chondrites from the bulk solar system, if primary chondrules and/or CAIs have been altered beyond recognition. Isolated olivine and pyroxene grains that range from approx. 5 microns to several hundred microns have been reported in CI chondrites, and acid residues of Orgueil were found to contain refractory oxides with oxygen isotopic compositions matching CAIs. However, the only CAI found to be unambiguously preserved in a CI chondrite was identified in Ivuna. The Ivuna CAI's primary mineralogy, small size (approx.170 microns), and fine-grained igneous texture classify it as a compact type A. Aqueous alteration infiltrated large portions of the CAI, but other regions remain pristine. The major primary phases are melilite (Ak 14-36 ), grossmanite (up to 20.8 wt.% TiO 2 ), and spinel. Both melilite and grossmanite have igneous textures and zoning patterns. An accretionary rim consists primarily of olivine (Fa 2-17 ) and low-Ca pyroxene (Fs 2-10 ), which could be either surviving CI2 material or a third lithology.

Mars Exploration Rover APXS Results from Matijevic Hill

NASA Technical Reports Server (NTRS)

Cohen, B. A.; Clark, B. C.; Gellert, R.; Klingelhoefer, G.; Ming, D. W.; Mittlefehldt, D. W.; Morris, R. V.; Schrader, C. M.; Schroeder, C.; Yen, A. S.;

Mineralogy of Tagish Lake, a Unique Type 2 Carbonaceous Chondrite

NASA Technical Reports Server (NTRS)

Gounelle, M.; Zolensky, M. E.; Tonui, E.; Mikouchi, T.

2001-01-01

We have identified in Tagish Lake an abondant carbonate-poor lithology and a less common carbonate-rich lithology. Tagish Lake shows similarities and differences with CMs and CI1s. It is a unique carbonaceous chondrite recording specific aqueous alteration conditions. Additional information is contained in the original extended abstract.

Oxygen, Magnesium, and Aluminum Isotopes in the Ivuna CAI: Re-Examining High-Temperature Fractionations in CI Chondrites

NASA Astrophysics Data System (ADS)

Frank, D. R.; Huss, G. R.; Nagashima, K.; Zolensky, M. E.; Le, L.

2017-07-01

The only whole CAI preserved in the aqueously altered CI chondrites is 16O-rich and has no resolvable radiogenic Mg. Accretion of CAIs by the CI parent object(s) may limit the precision of cosmochemical models that require a CI starting composition.

Aqueous biphasic extraction process with pH and particle control

DOEpatents

Chaiko, D.J.; Mensah-Biney, R.

1995-05-02

A process for aqueous biphasic extraction of metallic oxides and the like from substances containing silica. Control of media pH enables efficient and effective partition of mixture components. The inventive method may be employed to remove excess silica from kaolin clay. 2 figs.

Subcritical fracturing of shales under chemically reactive conditions

NASA Astrophysics Data System (ADS)

Chen, X.; Callahan, O. A.; Eichhubl, P.; Olson, J. E.

2016-12-01

Growth of opening-mode fractures under chemically reactive subsurface conditions is potentially relevant for seal integrity in subsurface CO2 storage and hazardous waste disposal. Using double-torsion load relaxation tests we determine mode-I fracture toughness (KIC), subcritical index (SCI), and the stress-intensity factor vs fracture velocity (K-V) behavior of Marcellus, Woodford, and Mancos shales. Samples are tested under ambient air and aqueous conditions with variable NaCl and KCl concentrations, variable pH, and temperatures of up to 70. Under ambient air condition, KIC determined from double torsion tests is 1.3, 0.6, and 1.1 MPam1/2 for Marcellus, Woodford, and Mancos shales, respectively. SCI under ambient air condition is between 55 and 90 for the shales tested. Tests in aqueous solutions show a significant drop of KIC compared to ambient air condition. For tests in deionized water, KIC reduction is 18.5% for Marcellus and 47.0% for Woodford. The presence of aqueous fluids also results in a reduction of the SCI up to 85% compared to ambient condition. K-V curves generally obey a power-law relation throughout the load-relaxation period. However, aqueous-based tests on samples result in K-V curves deviating from the power-law relation, with the SCI values gradually decreasing with time during the relaxation period. This non-power-law behavior is obvious in Woodford and Mancos, but negligible in Marcellus. We find that the shales interact with the aqueous solution both at the fracture tip and within the rock matrix during subcritical fracturing. For Marcellus shale, water mainly interacts with the fracture tip on both tests due to low matrix permeability and less reactive mineral composition. However, Woodford and Mancos react strongly with water causing significant sample degradation. The competition between degradation and fracture growth results in the time-dependent SCI: at lower fracture velocities, the tip interacts longer with the chemically altered area around the tip; at higher fracture velocities, the fracture propagates through the altered area before significant degradation. Our results display strong weakening effects of chemically reactive fluids on subcritical fracture properties with implications on subsurface storage seal performance.

Evidences of early aqueous Mars: Implications on the origin of branched valleys in the Ius Chasma, Mars

NASA Astrophysics Data System (ADS)

Martha, Tapas R.; Jain, Nirmala; Vamshi, Gasiganti T.; Vinod Kumar, K.

2017-11-01

This study shows results of morphological and spectroscopic analyses of Ius Chasma and its southern branched valleys using Orbiter datasets such as Mars Reconnaissance Orbiter (MRO)-Compact Reconnaissance Imaging Spectrometer for Mars (CRISM), High Resolution Imaging Science Experiment (MRO-HiRISE) and digital terrain model (HRSC-DTM). Result of the spectral analysis reveals presence of hydrated minerals such as opal, nontronite and vermiculite in the floor and wall rock areas Ius Chasma indicating alteration of parent rock in an water rich environment of early Mars. Topographic gradient and morphological evidences such as V-shaped valleys with theatre shaped stubby channels, dendritic drainage and river piracy indicate that these valleys were initially developed by surface runoff due to episodic floods and further expanded due to groundwater sapping controlled by faults and fractures. Minerals formed by aqueous alteration during valley formation and their intricate association with different morphological domains suggest that surface runoff played a key role in the development of branched valleys south of Ius Chasma on Mars.

FIB-TEM Investigations of Fe-NI-Sulfides in the CI Chondrites Alais and Orgueil

NASA Technical Reports Server (NTRS)

Berger, Eve L.; Lauretta, D. S.; Zega, T. J.; Keller, L. P.

2013-01-01

The CI chondrites are primitive meteorites with bulk compositions matching the solar photosphere for all but the lightest elements. They have been extensively aqueously altered, and are composed primarily of fine-grained phyllosilicate matrix material which is host to carbonates, sulfates, sulfides, and minor amounts of olivine and pyroxene. The alteration, while extensive, is heterogeneous. For example, CI-chondrite cubanite and carbonate grains differ on mm to sub-mm scales, demonstrating multiple aqueous episodes. CI-chondrite variability is also evidenced by degree of brecciation, abundance and size of coarse-grained phyllosilicates, olivine and pyroxene abundance, as well as Ni-content and size of sulfide grains. Our previous work revealed Orgueil sulfide grains with variable Ni-contents, metal:S ratios, crystal structures and textures. We continue to explore the variability of CI-chondrite pyrrhotite (Po, (FeNi)1-xS) and pentlandite (Pn, (Fe,Ni)9S8) grains. We investigate the microstructure of sulfides within and among CI-chondrite meteorites in order to place constraints on the conditions under which they formed.

Cross-phase separation of nanowires and nanoparticles

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

Qian, Fang; Duoss, Eric; Han, Jinkyu

In one embodiment, a process includes creating a mixture of an aqueous component, nanowires and nanoparticles, and a hydrophobic solvent and allowing migration of the nanowires to the hydrophobic solvent, where the nanoparticles remain in the aqueous component. Moreover, the nanowires and nanoparticles are in the aqueous component before the migration.

REMOVAL OF CHLORIDE FROM AQUEOUS SOLUTIONS

DOEpatents

Schulz, W.W.

1959-08-01

The removal of chlorides from aqueons solutions is described. The process involves contacting the aqueous chloride containing solution with a benzene solution about 0.005 M in phenyl mercuric acetate whereby the chloride anions are taken up by the organic phase and separating the organic phase from the aqueous solutions.

From synthetic montroseite VOOH to topochemical paramontroseite VO2 and their applications in aqueous lithium ion batteries.

PubMed

Xu, Yang; Zheng, Lei; Xie, Yi

2010-11-28

Synthetic montroseite VOOH has been successfully prepared via a simple template-free hydrothermal route on a large scale for the first time-after sixty years of delay. The as-obtained sample shows a hierarchical morphology of urchin-like nanoarchitecture with hollow interiors consisting of well-crystalline nanorods standing vertically on the shell surface. Time-dependent experiments illustrated that these hierarchical hollow nanourchins were formed through the hydrolysis-driven Kirkendall effect coupled with a new-phased vanadium oxyhydroxide V(10)O(14)(OH)(2) precursor templated approach. Meanwhile, the as-obtained VOOH hollow nanourchins could convert topochemically to paramontroseite VO(2) without altering the size and original appearance during the annealing process due to the extreme structural similarity revealed by crystal structure analysis. Furthermore, the improved electrochemical performance of both montroseite VOOH and paramontroseite VO(2) hierarchical hollow structures toward Li uptake and release verifies their potential applications as anode materials in aqueous lithium ion batteries. These improved electrochemical properties could be ascribed to the synergetic effect of the microscopic tunneled crystal structure and macroscopic hollow morphological features, which provide the easy infiltration of electrolyte, short diffusion lengths for lithium ions and electron transport as well as sufficient void space to buffer the volume change.

Hazardous Waste Minimization Assessment: Fort Campbell, Kentucky

DTIC Science & Technology

1991-03-01

Used Oii - Better Operating Practices . Selective Segregation 97 Used Oil - Process Change - Fast Lube Oil Change System (FLOCS) 98 Caustic Wastes...Product Substitution 98 Caustic Wastes - Process Change - Hot Tank (Equipment) Modifications 98 Aqueous or Caustic Wastes - Process Change - Dry Ovens...Aqueous or Caustic Wastes - Equipment Leasiag 102 Dirty Rags/Uniforms • Onsite/Offsite Recycling - Laundry Service 103 Treatment 103 Used Oil - Onsite

Process for the combined removal of SO.sub.2 and NO.sub.x from flue gas

DOEpatents

Chang, Shih-Ger; Liu, David K.; Griffiths, Elizabeth A.; Littlejohn, David

1988-01-01

The present invention in one aspect relates to a process for the simultaneous removal of NO.sub.x and SO.sub.2 from a fluid stream comprising mixtures thereof and in another aspect relates to the separation, use and/or regeneration of various chemicals contaminated or spent in the process and which includes the steps of: (A) contacting the fluid stream at a temperature of between about 105.degree. and 180.degree. C. with a liquid aqueous slurry or solution comprising an effective amount of an iron chelate of an amino acid moiety having at least one --SH group; (B) separating the fluid stream from the particulates formed in step (A) comprising the chelate of the amino acid moiety and fly ash; (C) washing and separating the particulates of step (B) with an aqueous solution having a pH value of between about 5 to 8; (D) subsequently washing and separating the particulates of step (C) with a strongly acidic aqueous solution having a pH value of between about 1 to 3; (E) washing and separating the particulates of step (D) with an basic aqueous solution having a pH value of between about 9 to 12; (F) optionally adding additional amino acid moiety, iron (II) and alkali to the aqueous liquid from step (D) to produce an aqueous solution or slurry similar to that in step (A) having a pH value of between about 4 to 12; and (G) recycling the aqueous slurry of step (F) to the contacting zone of step (A). Steps (D) and (E) can be carried out in the reverse sequence, however the preferred order is (D) and then (E). In another preferred embodiment the present invention provides a process for the removal of NO.sub.x, SO.sub.2 and particulates from a fluid stream which includes the steps of (A) injecting into a reaction zone an aqueous solution itself comprising (i) an amino acid moiety selected from those described above; (ii) iron (II) ion; and (iii) an alkali, wherein the aqueous solution has a pH of between about 4 and 11; followed by solids separation and washing as is described in steps (B), (C), (D) and (E) above. The overall process is useful to reduce acid rain components from combustion gas sources.

Method for producing catalysis from coal

DOEpatents

Farcasiu, Malvina; Derbyshire, Frank; Kaufman, Phillip B.; Jagtoyen, Marit

1998-01-01

A method for producing catalysts from coal is provided comprising mixing an aqueous alkali solution with the coal, heating the aqueous mixture to treat the coal, drying the now-heated aqueous mixture, reheating the mixture to form carbonized material, cooling the mixture, removing excess alkali from the carbonized material, and recovering the carbonized material, wherein the entire process is carried out in controlled atmospheres, and the carbonized material is a hydrocracking or hydrodehalogenation catalyst for liquid phase reactions. The invention also provides for a one-step method for producing catalysts from coal comprising mixing an aqueous alkali solution with the coal to create a mixture, heating the aqueous mixture from an ambient temperature to a predetermined temperature at a predetermined rate, cooling the mixture, and washing the mixture to remove excess alkali from the treated and carbonized material, wherein the entire process is carried out in a controlled atmosphere.

Process for preparing a stabilized coal-water slurry

DOEpatents

Givens, E.N.; Kang, D.

1987-06-23

A process is described for preparing a stabilized coal particle suspension which includes the steps of providing an aqueous media substantially free of coal oxidizing constituents, reducing, in a nonoxidizing atmosphere, the particle size of the coal to be suspended to a size sufficiently small to permit suspension thereof in the aqueous media and admixing the coal of reduced particle size with the aqueous media to release into the aqueous media coal stabilizing constituents indigenous to and carried by the reduced coal particles in order to form a stabilized coal particle suspension. The coal stabilizing constituents are effective in a nonoxidizing atmosphere to maintain the coal particle suspension at essentially a neutral or alkaline pH. The coal is ground in a nonoxidizing atmosphere such as an inert gaseous atmosphere to reduce the coal to a sufficient particle size and is admixed with an aqueous media that has been purged of oxygen and acid-forming gases. 2 figs.

Process for preparing a stabilized coal-water slurry

DOEpatents

Givens, Edwin N.; Kang, Doohee

1987-01-01

A process for preparing a stabilized coal particle suspension which includes the steps of providing an aqueous media substantially free of coal oxidizing constituents, reducing, in a nonoxidizing atmosphere, the particle size of the coal to be suspended to a size sufficiently small to permit suspension thereof in the aqueous media and admixing the coal of reduced particle size with the aqueous media to release into the aqueous media coal stabilizing constituents indigenous to and carried by the reduced coal particles in order to form a stabilized coal particle suspension. The coal stabilizing constituents are effective in a nonoxidizing atmosphere to maintain the coal particle suspension at essentially a neutral or alkaline pH. The coal is ground in a nonoxidizing atmosphere such as an inert gaseous atmosphere to reduce the coal to a sufficient particle size and is admixed with an aqueous media that has been purged of oxygen and acid-forming gases.

Method for producing catalysts from coal

DOEpatents

Farcasiu, M.; Derbyshire, F.; Kaufman, P.B.; Jagtoyen, M.

1998-02-24

A method for producing catalysts from coal is provided comprising mixing an aqueous alkali solution with the coal, heating the aqueous mixture to treat the coal, drying the now-heated aqueous mixture, reheating the mixture to form carbonized material, cooling the mixture, removing excess alkali from the carbonized material, and recovering the carbonized material, wherein the entire process is carried out in controlled atmospheres, and the carbonized material is a hydrocracking or hydrodehalogenation catalyst for liquid phase reactions. The invention also provides for a one-step method for producing catalysts from coal comprising mixing an aqueous alkali solution with the coal to create a mixture, heating the aqueous mixture from an ambient temperature to a predetermined temperature at a predetermined rate, cooling the mixture, and washing the mixture to remove excess alkali from the treated and carbonized material, wherein the entire process is carried out in a controlled atmosphere. 1 fig.

Pretreatment of Biomass by Aqueous Ammonia for Bioethanol Production

NASA Astrophysics Data System (ADS)

Kim, Tae Hyun; Gupta, Rajesh; Lee, Y. Y.

The methods of pretreatment of lignocellulosic biomass using aqueous ammonia are described. The main effect of ammonia treatment of biomass is delignification without significantly affecting the carbohydrate contents. It is a very effective pretreatment method especially for substrates that have low lignin contents such as agricultural residues and herbaceous feedstock. The ammonia-based pretreatment is well suited for simultaneous saccharification and co-fermentation (SSCF) because the treated biomass retains cellulose as well as hemicellulose. It has been demonstrated that overall ethanol yield above 75% of the theoretical maximum on the basis of total carbohydrate is achievable from corn stover pretreated with aqueous ammonia by way of SSCF. There are two different types of pretreatment methods based on aqueous ammonia: (1) high severity, low contact time process (ammonia recycle percolation; ARP), (2) low severity, high treatment time process (soaking in aqueous ammonia; SAA). Both of these methods are described and discussed for their features and effectiveness.

Development of CFC-Free Cleaning Processes at the NASA White Sands Test Facility

NASA Technical Reports Server (NTRS)

Beeson, Harold; Kirsch, Mike; Hornung, Steven; Biesinger, Paul

1995-01-01

The NASA White Sands Test Facility (WSTF) is developing cleaning and verification processes to replace currently used chlorofluorocarbon-113- (CFC-113-) based processes. The processes being evaluated include both aqueous- and solvent-based techniques. The presentation will include the findings of investigations of aqueous cleaning and verification processes that are based on a draft of a proposed NASA Kennedy Space Center (KSC) cleaning procedure. Verification testing with known contaminants, such as hydraulic fluid and commonly used oils, established correlations between nonvolatile residue and CFC-113. Recoveries ranged from 35 to 60 percent of theoretical. WSTF is also investigating enhancements to aqueous sampling for organics and particulates. Although aqueous alternatives have been identified for several processes, a need still exists for nonaqueous solvent cleaning, such as the cleaning and cleanliness verification of gauges used for oxygen service. The cleaning effectiveness of tetrachloroethylene (PCE), trichloroethylene (TCE), ethanol, hydrochlorofluorocarbon-225 (HCFC-225), tert-butylmethylether, and n-Hexane was evaluated using aerospace gauges and precision instruments and then compared to the cleaning effectiveness of CFC-113. Solvents considered for use in oxygen systems were also tested for oxygen compatibility using high-pressure oxygen autoignition and liquid oxygen mechanical impact testing.

[Petrological Analysis of Astrophysical Dust Analog Evolution

NASA Technical Reports Server (NTRS)

Rietmeijer, Frans J. M.

1997-01-01

This project "Petrological analysis of astrophysical dust analog evolution" was initiated to try to understand the vapor phase condensation, and the nature of the reaction products, in circumstellar environments, such as the solar nebula 4,500 Myrs ago, and in the interstellar medium. Telescope-based infrared [IR] spectroscopy offers a broad-scale inventory of the various types of dust in these environments but no details on small-scale variations in terms of chemistry and morphology and petrological phase relationships. Vapor phase condensation in these environments is almost certainly a non-equilibrium process. The main challenge to this research was to document the nature of this process that, based on astrophysical observations, seems to yield compositionally consistent materials. This observation may suggest a predictable character during non-equilibrium condensation. These astrophysical environments include two chemically distinct, that is, oxygen-rich and carbon-rich environments. The former is characterized by silicates the latter by carbon-bearing solids. According to cosmological models of stellar evolution circumstellar dust accreted into protoplanets wherein thermal and/or aqueous processes will alter the dust under initially, non-equilibrium conditions.

Berberis vulgaris L. effects on oxidative stress and liver injury in lead-intoxicated mice.

PubMed

Laamech, Jawhar; El-Hilaly, Jaouad; Fetoui, Hamadi; Chtourou, Yassine; Gouitaa, Hanane; Tahraoui, Adel; Lyoussi, Badiaa

2017-03-01

Background Berberis vulgaris L. (BV), commonly known as "Aghriss" in Moroccan pharmacopoeia, is used to cure liver disorders and other diseases. The present study aimed to investigate the protective effect of BV aqueous extract against lead-induced toxicity in mice liver. Methods Sixty IOPS mice were divided into six groups and were treated as follows: group 1 (normal control) received double distilled water; group 2 (toxic control) received lead acetate (5 mg/kg body weight/day) in double distilled water for 40 days; groups 3-6 received BV aqueous extract at doses of 25, 50, 100 and 150 mg/kg body weight , respectively, once daily for 30 days from 11 day after beginning of lead acetate exposure to the end of the experiment. Results Toxic control group showed a significant alteration of serum alanine-aminotransferase (ALT), aspartate-aminotransferase (AST), total cholesterol (TC), total bilirubin (TB), catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx) and reduced glutathione (GSH). Histological assessment of lead-intoxicated mice liver revealed alterations in hepatocytes and focal necrosis. BV treatment significantly prevented lead accumulation, increased ALT, AST, TC, and TB, inhibited lipid peroxidation and protein carbonyls(PCO) formation. Additionally, BV extract normalized the antioxidant enzymes (CAT, SOD and GPx), GSH and architecture of liver tissues. Conclusions BV aqueous extract exerts significant hepatoprotective effects against lead-induced oxidative stress and liver dysfunction. The BV effect may be mediated through the enhancement of antioxidant status, lead-chelating abilities and free radicals quenching.

Structural alteration of hexagonal birnessite by aqueous Mn(II): Impacts on Ni(II) sorption

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

Lefkowitz, Joshua P.; Elzinga, Evert J.

We studied the impacts of aqueous Mn(II) (1 mM) on the sorption of Ni(II) (200 μM) by hexagonal birnessite (0.1 g L- 1) at pH 6.5 and 7.5 with batch experiments and XRD, ATR-FTIR and Ni K-edge EXAFS analyses. In the absence of Mn(II)aq, sorbed Ni(II) was coordinated predominantly as triple corner-sharing complexes at layer vacancies at both pH values. Introduction of Mn(II)aq into Ni(II)-birnessite suspensions at pH 6.5 caused Ni(II) desorption and led to the formation of edge-sharing Ni(II) complexes. This was attributed to competitive displacement of Ni(II) from layer vacancies by either Mn(II) or by Mn(III) formed throughmore » interfacial Mn(II)-Mn(IV) comproportionation, and/or incorporation of Ni(II) into the birnessite lattice promoted by Mn(II)-catalyzed recrystallization of the sorbent. Similar to Mn(II)aq, the presence of HEPES or MES caused the formation of edge-sharing Ni(II) sorption complexes in Ni(II)-birnessite suspensions, which was attributed to partial reduction of the sorbent by the buffers. At pH 7.5, interaction with aqueous Mn(II) caused reductive transformation of birnessite into secondary feitknechtite that incorporated Ni(II), enhancing removal of Ni(II) from solution. These results demonstrate that reductive alteration of phyllomanganates may significantly affect the speciation and solubility of Ni(II) in anoxic and suboxic environments.« less

Evidence of ancient microbial activity on Mars

NASA Astrophysics Data System (ADS)

Wallis, Jamie; Wickramasinghe, N. C.; Wallis, Daryl H.; Miyake, Nori; Wallis, M. K.; Hoover, Richard B.

2015-09-01

We report for the first time in situ observations of a relatively rare secondary iron arsenate-sulphate mineral named bukovskýite - Fe3+ 2(As5+O4)(S6+O4)(OH)•7(H2O) - found in a shock melt vein of the Tissint Martian meteorite. It is hypothesised that the mineral formed when high concentrations of aqueous H+, Fe(III), SO4 and AsO4 were maintained for long periods of time in microenvironments created within wet subsurface Martian clays. The aqueous H+, Fe(III), SO4 and AsO4 species arose from the microbial oxidation of FeS2 with concurrent release of sequestrated As. The availability of aqueous AsO4 would also be complemented by dissolution by-products of the microbial reduction of Feoxides influenced by dissolved organic matter that alters the redox state and the complexation of As, thus shifting As partitioning in favour of the solute phase. This hypothesis is substantially supported by SEM analysis of a 15μm spherical structure comprising of a carbonaceous outer coating with a inner core of FeS2 (pyrite) that showed the pyrite surface with spherical pits, and chains of pits, with morphologies distinct from abiotic alteration features. The pits and channels have a clustered, geometric distribution, typical of microbial activity, and are closely comparable to biologically mediated microstructures created by Fe- and S-oxidising microbes in the laboratory. These microstructures are interpreted as trace fossils resulting from the attachment of bacteria to the pyrite surfaces.

Compositional study of asteroids in the Erigone collisional family using visible spectroscopy at the 10.4m GTC

NASA Astrophysics Data System (ADS)

Morate, David; de León, Julia; De Prá, Mário; Licandro, Javier; Cabrera-Lavers, Antonio; Campins, Humberto; Pinilla-Alonso, Noemí; Alí-Lagoa, Víctor

2015-11-01

Asteroid families are formed by the fragments produced by the disruption of a common parent body (Bendjoya & Zappalà 2002). Primitive asteroids in the solar system are believed to have undergone less thermal processing than the S-complex asteroids. Thus, study of primitive asteroid families provides information about the solar system formation period. The Erigone collisional family, together with other three families (Polana, Clarissa and Sulamitis), are believed to be the origin of the two primitive Near-Earth asteroids that are the main targets of the NASA’s OSIRIS-REx ((101955) Bennu) and JAXA’s Hayabusa 2 ((162173) 1999 JU3) missions (Campins et al. 2010; Campins et al. 2013; Lauretta et al. 2010; Tsuda et al. 2013). These spacecrafts will visit the asteroids, and a sample of their surface material will be returned to Earth. Understanding of the families that are considered potential sources will enhance the scientific return of the missions. The main goal of the work presented here is to characterize the Erigone collisional family. Asteroid (163) Erigone has been classified as a primitive object (Bus 1999; Bus & Binzel 2002), and we expect the members of this family to be consistent with the spectral type of the parent body. We have obtained visible spectra (0.5-0.9 μm) for 101 members of the Erigone family, using the OSIRIS instrument at the 10.4m Gran Telescopio Canarias. We performed a taxonomical classification of these asteroids, finding that the number of primitive objects in our sample is in agreement with the hypothesis of a common parent body. In addition, we have found a significant fraction of asteroids in our sample that present evidences of aqueous alteration. Study of aqueous alterations is important, as it can give information on the heating processes of the early Solar System, and for the associated astrobiological implications (it has been suggested that the Earth’s present water supply was brought here by asteroids, instead of comets, in opposition to previous explanations (Morbidelli et al. 2000).

Comparison of the Mineralogy of Comet Wild 2 Coma Grains to Other Astromaterials

NASA Technical Reports Server (NTRS)

Frank, David; Zolensky, Michael

2010-01-01

We propose that Kuiper Belt samples (in this case comet coma grains from the Jupiter family comet Wild 2) are recognizably different from the bulk of materials in outer belt asteroids, because of their different formation positions and times in the early solar system. We believe this despite similarities found between some Wild 2 grains and components of carbonaceous chondrites (i.e. some CAI and chondrules). Kuiper Belt samples must preserve measurable mineralogical and compositional evidence of formation at unique positions and times in the early solar nebula, and these formational differences must have imparted recognizable special characteristics. We hypothesize that these characteristics include: (1) Unique major element compositional ranges of common astromaterial minerals, especially olivine and pyroxene; (2) Unique minor element compositions of major silicate phases, especially olivine and low-Ca pyroxene; (3) Degree and effects of radiation processing -- including amorphous rims, metal coatings, and Glass with Embedded Metal and Sulfides (GEMS); (4) Presence of abundant presolar silicate grains as recognized by anomalous oxygen in silicates; (5) Oxidation state of the mineral assemblage. We are working our way through all available Wild 2 samples, selecting 1-2 non-consecutive viable TEM grids from each possible extracted Wild 2 grain. We especially prefer TEM grids from grains for which complete mineralogical details have not been published (which is to say the majority of the extracted grains). We are performing a basic mineralogic survey by E-beam techniques, to establish the essential features of the extracted Wild 2 grains. We are making a particular effort to carefully and accurately measure minor elements of olivine and pyroxene, as these minerals are widespread in astromaterials, and comparisons of their compositions will serve to place the Wild 2 silicates in contact with asteroids, meteorites and chondritic interplanetary dust particles processing. We are also making a special effort to search for mineralogical products of aqueous alteration, since their presence would reveal that Wild 2 was once internally heated, a result with dramatic implications for models of early solar system primitive bodies. Thus far carbonates are the only potential evidence for aqueous alteration for Wild 2.

Aqueous alteration and brecciation in Bells, an unusual, saponite-bearing, CM chondrite

NASA Astrophysics Data System (ADS)

Brearley, Adrian J.

1995-06-01

The petrological and mineralogical characteristics of the unusual CM2 chondrite, Bells, have been investigated in detail by scanning electron microscopy (SEM), electron microprobe analysis (EPMA), and transmission electron microscopy (TEM). Bells is a highly brecciated chondrite which contains few intact chondrules, a very low abundance of refractory inclusions, and is notable in having an unusually high abundance of magnetite, which is disseminated throughout the fine-grained matrix. Fragmental olivines and pyroxenes are common and, based on compositional data, appear to have been derived from chondrules as a result of extensive brecciation. The fine-grained mineralogy of matrix in Bells differs considerably from other CM chondrites and has closer affinities to matrix in CI chondrites. The dominant phases are fine-grained saponite interlayered with serpentine, and phases such as tochilinite and cronstedtite, which are typical of CM chondrite matrices, are entirely absent. Pentlandite, pyrrhotite, magnetite, anhydrite, calcite, and rare Ti-oxides also occur as accessory phases. Based on its oxygen and noble gas isotopic compositions (Zadnik, 1985; Rowe et al., 1994), Bells can be considered to be a CM2 chondrite, although its bulk composition shows some departures from the typical range exhibited by this group. However, these variations in bulk chemistry are entirely consistent with the observed mineralogy of Bells. The unusual fine-grained mineralogy of Bells matrix can be reasonably attributed to the combined effects of aqueous alteration and advanced brecciation in a parent body environment. Extensive brecciation has assisted aqueous alteration by reducing chondrules and mineral grains into progressively smaller grains with high surface areas, which are more susceptible to dissolution reactions involving aqueous fluids. This has resulted in the preferential dissolution of Fe-rich chondrule olivines, which are now completely absent in Bells although present in other CM chondrites. The formation of saponite in Bells probably resulted from the dissolution of relatively silica-rich phases, such as pyroxene and olivine, that were derived from chondrules. The result of such dissolution reactions would be to increase the activity of silica in the fluid phase, at least on a localized scale, stabilizing saponite in preference to serpentine. An increase in aSiO 2 would also have destabilized preexisting cronstedtite which may have reacted to form magnetite and MgFe serpentine under conditions of constant ƒO 2 .

First insights on the molybdenum-copper Bled M'Dena complex (Eglab massif, Algeria)

NASA Astrophysics Data System (ADS)

Lagraa, Karima; Salvi, Stefano; Béziat, Didier; Debat, Pierre; Kolli, Omar

2017-03-01

Molybdenum-Copper showings in the Eglab massif (eastern part of the Reguibat rise of Algeria), are found in quartz-monzodiorite and granodiorite of the Bled M'Dena complex, a Paleoproterozoic circular structure of ∼5 km in diameter, comprising volcanic and intrusive suites. The latter consist of quartz-diorite, quartz-monzodiorite and granodiorite with a metaluminous normative composition. They display an "adakitic character" with moderate light rare-earth element (LREE) enrichment, minor Eu anomalies, high Sr/Y ratio and low Yb concentration, suggestive of a hydrous, arc magma of volcanic-arc affinity. The mineralization occurs mostly in quartz + molybdenite + chalcopyrite stockwork veins marked by widespread propylitic alteration along the selvages. Molybdenite and chalcopyrite are commonly associated with calcite, which precipitated at relatively late stages of the hydrothermal alteration. Fluid inclusions related to the mineralization stage, range from aqueous to aqueous-carbonic to solid bearing. The latter inclusions have the highest homogenization temperature (up to ∼400 °C), are salt saturated, and commonly contain molybdenite and/or chalcopyrite crystals. The petrology and geochemistry of the host rocks, the style of the hydrothermal alteration, the ore mineral associations, and the characteristics of the fluid inclusions, are all coherent in indicating that the Bled M'Dena represents a Paleoproterozoic porphyry style Mo mineralization, which is far unreported in the African continent.

Membrane Treatment of Aqueous Film Forming Foam (AFFF) Wastes for Recovery of Its Active Ingredients

DTIC Science & Technology

1980-10-01

T ME1MBRANE TREATMENT OF AQUEOUS FILM FORMING FOAM~ (AFFF) WASTES FOR RECOVERY OFI Fts ACTIVE INGREDIENTS FINAL REPORT October 1980 by Edward S. K...OF THIS PAGEOPMn Date AVntr* d)__ ---- Ultrafiltration (UF) and Reverse Osmosis (RO) treatment of Aqueous Film Forming Foam (AFFF) solutions was...of Aqueous Film Forming Foam (AFFF) solutions was investigated to determine the feasibility of employing membrane processes to separate and recover

Mineralogy and Petrology of Amoeboid Olivine Inclusions in CO3 Chondrites: Relationship to Parent-Body Aqueous Alteration

NASA Technical Reports Server (NTRS)

Chizmadia, Lysa J.; Rubin, Alan E.; Wasson, John T.

2003-01-01

Petrographic and mineralogic studies of amoeboid olivine inclusions (AOIs) in CO3 carbonaceous chondrites reveal that they are sensitive indicators of parent-body aqueous and thermal alteration. As the petrologic subtype increases from 3.0 to 3.8, forsteritic olivine (Fa(sub 0-1)) is systematically converted into ferroan olivine (Fa(sub 60-75)). We infer that the Fe, Si and O entered the assemblage along grain boundaries, forming ferroan olivine that filled fractures and voids. As temperatures increased, Fe(+2) from the new olivine exchanged with Mg(+2) from the original AOI to form diffusive haloes around low-FeO cores. Cations of Mn(+2), Ca(+2) and Cr(+3) were also mobilized. The systematic changes in AOI textures and olivine compositional distributions can be used to refine the classification of CO3 chondrites into subtypes. In subtype 3.0, olivine occurs as small forsterite grains (Fa(sub 0-1)), free of ferroan olivine. In petrologic subtype 3.2, narrow veins of FeO-rich olivine have formed at forsterite grain boundaries. With increasing alteration, these veins thicken to form zones of ferroan olivine at the outside AOI margin and within the AOI interior. By subtype 3.7, there is a fairly broad olivine compositional distribution in the range Fa(sub 63-70), and by subtype 3.8, no forsterite remains and the high-Fa peak has narrowed, Fa(sub 64-67). Even at this stage, there is incomplete equilibration in the chondrite as a whole (e.g., data for coarse olivine grains in Isna (CO3.8) chondrules and lithic clasts show a peak at Fa(sub39)). We infer that the mineral changes in A01 identified in the low petrologic types required aqueous or hydrothermal fluids whereas those in subtypes greater than or equal to 3.3 largely reflect diffusive exchange within and between mineral grains without the aid of fluids.

The redox state of iron in the matrix of CI, CM and metamorphosed CM chondrites by XANES spectroscopy

NASA Astrophysics Data System (ADS)

Beck, P.; De Andrade, V.; Orthous-Daunay, F.-R.; Veronesi, G.; Cotte, M.; Quirico, E.; Schmitt, B.

2012-12-01

Carbonaceous chondrites record the action of water at some point of their petrological history. These meteorites are usually connected to low albedo asteroid, which present visible/near-IR absorption explained by iron related absorption within phyllosilicates and oxides. In order to obtain quantitative insight into the mineralogy of iron-bearing phases, we have measured X-ray absorption near-edge spectroscopy at the iron K-edge of matrix from carbonaceous chondrites. This method enables to constrain the redox state and environment of iron in these meteorites. For this study, we selected seven CM chondrites and the CI Orgueil, expected to span a range of aqueous alteration degrees. Our analysis of the pre-edge features show that the redox state of Orgueil (CI) is dominated by octahedral Fe and that the Fe3+/(Fe3++Fe2+) atomic ratio is above 80%. Full-inversion of the spectra suggests that the iron budget is dominated by iron oxides, with additional contributions from phyllosilicate. In the case of the CM, the iron speciation appears different that in the case of Orgueil. Cronstedtite is identified from the inversion of the spectra, and suggested by the presence of significant amount of tetrahedral Fe3+. Within the CM chondrites, a trend of aqueous alteration appears presents, and which is roughly correlated to the scheme defined by Rubin et al. (2007). This trend is characterized by an increase in the amount of iron oxides. Two shock metamorphosed CM are present in our dataset (PCA 91008, WIS 91600). If WIS 91600 does not appear distinguishable, from the CM trend, in the case of PCA 91008, shock metamorphism did impact the pre-edge intensity and an increased amount of anhydrous silicates is found. Although the matrix was dehydrated, significant amount of Fe3+ is still present, providing a memory of the aqueous alteration.

Meteoric Water Alteration of Soil and Landscapes at Meridiani Planum, Mars

NASA Astrophysics Data System (ADS)

Amundson, R.

2017-12-01

The geomorphology and geochemistry data gathered by the MER Opportunity at Meridiani Planum is arguably the richest data set relevant soil research on Mars. Much of the data, particularly with respect to outcrops at Victoria Crater, have been only partially published and analyzed. Here, the previously published geochemical profile of Endurance Crater is compared to that of Victoria Crater, to understand aspects of the post-depositional aqueous and chemical alteration of the Meridiani land surface. The landsurface bears cracking patterns similar to those produced by multiple episodes of wetting and drying in expansive materials on Earth. The geochemical profiles at both craters are nearly identical, suggesting (using mass balance methods) that a very homogenous sedimentary deposit has been engulfed by the apparent surficial addition of S, Cl, and Br (and associated cations) since exposure to the atmosphere. The chemistry and mineralogy at both locations is one where the most insoluble of the added components resides near the land surface (Ca sulfates), and the more soluble components are concentrated at greater depths in a vertical pattern consistent with their solubility in water. The profiles, when compared to those on Earth (and to physical constraints), are unambiguously those generated by the downward movement of meteoric water. When this aqueous alteration and soil formation occurred is not well constrained, but progressed between late Noachian to Amazonian times. The exposure of the Victoria crater walls, which occurred likely less than 107y ago (late Amazonian), shows the accumulation of dust as well as evidence for aqueous concentration of NaBr, possibly by deliquescence. By direct comparison to Earth, the regional soil at Meridiani Planum is a Typic Petrogypsid, bearing similarities to very ancient soils formed in the Atacama Desert of Chile. The amount of water required to produce the soils ranges from a very low (and physically unlikely) quantity of 2-4 m, to (more likely) possibly km's of water over the extended time period that is needed to produce similar soils on Earth.

Use of a fiber optic probe for organic species determination

DOEpatents

Ekechukwu, A.A.

1996-12-10

A fiber optic probe is described for remotely detecting the presence and concentration organic species in aqueous solutions. The probe includes a cylindrical housing with an organic species indicator, preferably diaminonaphthyl sulfonic acid adsorbed in a silica gel (DANS-modified gel), contained in the probe`s distal end. The probe admits aqueous solutions to the probe interior for mixing within the DANS-modified gel. An optical fiber transmits light through the DANS-modified gel while the indicator reacts with organic species present in the solution, thereby shifting the location of the fluorescent peak. The altered light is reflected to a receiving fiber that carries the light to a spectrophotometer or other analysis device. 5 figs.

Global Mineralogical and Aqueous Mars History Derived from OMEGA/Mars Express Data

NASA Astrophysics Data System (ADS)

Bibring, Jean-Pierre; Langevin, Yves; Mustard, John F.; Poulet, François; Arvidson, Raymond; Gendrin, Aline; Gondet, Brigitte; Mangold, Nicolas; Pinet, P.; Forget, F.; OMEGA Team; Berthé, Michel; Gomez, Cécile; Jouglet, Denis; Soufflot, Alain; Vincendon, Mathieu; Combes, Michel; Drossart, Pierre; Encrenaz, Thérèse; Fouchet, Thierry; Merchiorri, Riccardo; Belluci, GianCarlo; Altieri, Francesca; Formisano, Vittorio; Capaccioni, Fabricio; Cerroni, Pricilla; Coradini, Angioletta; Fonti, Sergio; Korablev, Oleg; Kottsov, Volodia; Ignatiev, Nikolai; Moroz, Vassilli; Titov, Dimitri; Zasova, Ludmilla; Loiseau, Damien; Pinet, Patrick; Doute, Sylvain; Schmitt, Bernard; Sotin, Christophe; Hauber, Ernst; Hoffmann, Harald; Jaumann, Ralf; Keller, Uwe; Arvidson, Ray; Duxbury, Tom; Neukum, G.

2006-04-01

Global mineralogical mapping of Mars by the Observatoire pour la Mineralogie, l'Eau, les Glaces et l'Activité (OMEGA) instrument on the European Space Agency's Mars Express spacecraft provides new information on Mars' geological and climatic history. Phyllosilicates formed by aqueous alteration very early in the planet's history (the ``phyllocian'' era) are found in the oldest terrains; sulfates were formed in a second era (the ``theiikian'' era) in an acidic environment. Beginning about 3.5 billion years ago, the last era (the ``siderikian'') is dominated by the formation of anhydrous ferric oxides in a slow superficial weathering, without liquid water playing a major role across the planet.

Use of a fiber optic probe for organic species determination

DOEpatents

Ekechukwu, Amy A.

1996-01-01

A fiber optic probe for remotely detecting the presence and concentration organic species in aqueous solutions. The probe includes a cylindrical housing with an organic species indicator, preferably diaminonaphthyl sulfonic acid adsorbed in a silica gel (DANS-modified gel), contained in the probe's distal end. The probe admits aqueous solutions to the probe interior for mixing within the DANS-modified gel. An optical fiber transmits light through the DANS-modified gel while the indicator reacts with organic species present in the solution, thereby shifting the location of the fluorescent peak. The altered light is reflected to a receiving fiber that carries the light to a spectrophotometer or other analysis device.

ION EXCHANGE PROCESS FOR THE RECOVERY AND PURIFICATION OF MATERIALS

DOEpatents

Long, R.S.; Bailes, R.H.

1958-04-15

A process for the recovery of certain metallic ions from aqueous solutions by ion exchange techniques is described. It is applicable to elements such as vanadium, chromium, nnanganese, and the like, which are capable of forming lower valent cations soluble in aqueous solutions and which also form ldgher valent anions soluble in aqueous acidic solutions. For example, small amounts of vanadium occurring in phosphoric acid prepared from phosphate rock may be recovered by reducing the vanadium to a trivalent cation adsorbing; the vanadium in a cationic exchange resin, then treating the resin with a suitable oxidizing agent to convert the adsorbed vanadium to a higher valent state, and finally eluting; the vanadium as an anion from the resin by means of an aqueous acidic solution.

Process for recovering pertechnetate ions from an aqueous solution also containing other ions

DOEpatents

Rogers, R.; Horwitz, E.P.; Bond, A.H.

1997-02-18

A solid/liquid process for the separation and recovery of TcO{sub 4}{sup {minus}1} ions from an aqueous solution is disclosed. The solid support comprises separation particles having surface-bonded poly(ethylene glycol) groups; whereas the aqueous solution from which the TcO{sub 4}{sup {minus}1} ions are separated contains a poly(ethylene glycol) liquid/liquid biphase-forming amount of a dissolved salt. A solid/liquid phase admixture of separation particles containing bound TcO{sub 4}{sup {minus}1} ions in such an aqueous solution that is free from MoO{sub 4}{sup {minus}2} ions is also contemplated, as is a chromatography apparatus containing that solid/liquid phase admixture. 15 figs.

Martian Weathering Environments of the Amazonian Indicated by Correlated Morphologic and Spectral Observation in Acidalia Planitia

NASA Astrophysics Data System (ADS)

Kraft, M. D.; Rogers, D.; Fergason, R. L.; Michalski, J. R.; Sharp, T. G.

2009-12-01

While much attention has been given to chemical alteration and the state of water on early Mars, it remains important to understand aqueous processes throughout Martian history, including the recent geologic past. It has been suggested that the Amazonian was marked primarily by anhydrous, oxidative weathering because Amazonian surfaces, such as the northern plains, lack hydration features in near-infrared spectra [1]. But high-silica materials (Surface Type 2, ST2) discovered by the Thermal Emission Spectrometer [2] that occur in the northern plains attest to aqueous alteration of silicate minerals. The questions are when did this occur and by what process? ST2 correlates spatially with outflow sediments and high-silica materials may have formed in large amounts of water related to outflow flooding events of the late Hesperian [3,4]. ST2 also may correspond to global ice-rich mantles, indicating formation in icy environments related to geologically recent climate fluctuations [3]. Can these very different mechanisms and environments be discerned? In a global study of TES spectra, Rogers et al. (2007) [5] found significant spectral differences between ST2 surfaces in northern and southern Acidalia Planitia that occur near 40-50° N. Several geomorphic transitions occur across latitudes, and many of these are directly or potentially related to Amazonian periglacial activity and occur in the 40-50° N range. This potential link between composition and periglacial morphology needs further exploration. We examined this relationship from 40-50° N in Acidalia Planitia, using Thermal Emission Imaging System (THEMIS) multispectral data to measure the local spectral properties of the surface. We identified a boundary between two surface spectral types that match closely the spectra of north and south Acidalia derived by Rogers et al. [2007]. This boundary is diffuse, occurring between 47-48° N in our study region in western Acidalia, and correlates with observed morphologic and thermophysical differences. Close examination of those surfaces with High Resolution Imaging Science Experiment (HiRISE) images shows that the area north of the boundary is a modified version of the southern surface, subdued and overprinted by periglacial polygonal ground. Thus, we think that ground ice has modified the surface morphology and, furthermore, that periglacial processing also modified the silicate composition of the northern surface materials. Weathering that created the northern Acidalia composition involved ground ice, and was likely similar to weathering in Antarctic soils, in which silica is mobilized by thin water films and deposited as gels [6]. By this mechanism, aqueous weathering on Mars has probably persisted into, and throughout, the Amazonian. References: [1] Bibring et al. (2006) Science, 312, 400-404. [2] Bandfield et al. (2000) Science, 287, 1626-1630. [3] Wyatt et al. (2004) Geology, 32, 645-648. [4] Tanaka et al. (2005) USGS Sci. Invest. Map 2888. [5] Rogers et al. (2007) J. Geophys. Res.,112, E02004. [6] Ugolini and Anderson (1973), Soil Sci., 105, 461-470.

Aqueous silicates in biological sol-gel applications: new perspectives for old precursors.

PubMed

Coradin, Thibaud; Livage, Jacques

2007-09-01

Identification of silica sol-gel chemistry with silicon alkoxide hydrolysis and condensation processes is common in modern materials science. However, aqueous silicates exhibit several features indicating that they may be more suitable precursors for specific fields of research and applications related to biology and medicine. In this Account, we illustrate the potentialities of such aqueous precursors for biomimetic studies, bio-hybrid material design, and bioencapsulation routes. We emphasize that the natural relevance, the biocompatibility, and the low ecological impact of silicate chemistry may balance its lack of diversity, flexibility, and processability.

SEPARATION PROCESS FOR TRANSURANIC ELEMENT AND COMPOUNDS THEREOF

DOEpatents

Magnusson, L.B.

1958-04-01

A process is described for the separation of neptunium, from aqueous solutions of neptunium, plutonium, uraniunn, and fission prcducts. This separation from an acidic aqueous solution of a tetravalent neptuniunn can be made by contacting the solution with a certain type of chelating,; agent, preferably dissolved in an organic solvent, to form a neptunium chelate compound. When the organic solvent is present, the neptunium chelate compound is extracted; otherwise, it precipitates from the aqueous solution and is separated by any suitable means. The chelating agent is a fluorinated BETA -diketone. such as trifluoroacetyl acetone.

Effects of dorzolamide on choroidal blood flow, ciliary blood flow, and aqueous production in rabbits.

PubMed

Reitsamer, Herbert A; Bogner, Barbara; Tockner, Birgit; Kiel, Jeffrey W

2009-05-01

To determine the effects of topical dorzolamide (a carbonic anhydrase inhibitor) on choroidal and ciliary blood flow and the relationship between ciliary blood flow and aqueous flow. The experiments were performed in four groups of pentobarbital-anesthetized rabbits treated with topical dorzolamide (2%, 50 microL). In all groups, intraocular pressure (IOP) and mean arterial pressure (MAP) at the eye level were measured continuously by direct cannulation. In group 1, aqueous flow was measured by fluorophotometry before and after dorzolamide treatment. In group 2, aqueous flow was measured after dorzolamide at normal MAP and while MAP was held constant at 80, 55, or 40 mm Hg with occluders on the aorta and vena cava. In group 3, the same MAP levels were used, and ciliary blood flow was measured transsclerally by laser Doppler flowmetry (LDF). In group 4, choroidal blood flow was measured by LDF with the probe tip positioned in the vitreous over the posterior pole during ramp increases and decreases in MAP before and after dorzolamide. Dorzolamide lowered IOP by 19% (P < 0.01) and aqueous flow by 17% (P < 0.01), and increased ciliary blood flow by 18% (P < 0.01), which was associated with a significant reduction in ciliary vasculature resistance (-7%, P < 0.01). Dorzolamide shifted the relationship between ciliary blood flow and aqueous flow downward relative to the previously determined control relationship in the rabbit. Dorzolamide did not alter choroidal blood flow, choroidal vascular resistance, or the choroidal pressure flow relationship. Acute topical dorzolamide is a ciliary vasodilator and has a direct inhibitory effect on aqueous production, but it does not have a detectable effect on choroidal hemodynamics at the posterior pole in the rabbit.

Effects of Cecropia pachystachya and Larrea divaricata aqueous extracts in mice.

PubMed

Bigliani, M C; Grondona, E; Zunino, P M; Ponce, A A

2010-07-01

Our studies were performed to investigate the effects of the aqueous extracts of Cecropia pachystachya and Larrea divaricata. These plants are used in folkloric medicine in infusion and were administered orally (0.76 g/kg) to male Albino Swiss mice for 16 days, on drink intake, organ weight/body weight (OW/BW x 100) ratio, histology, broqueoalveolar fluid (BALF) and elevated plus-maze (EPM). Feeding as well as body weight were unaffected by the consumption of these extracts. There were no signs of toxicity in BALF, morbidity or mortality during the study. C. pachystachya caused an increase in relative kidney OW/BW (p

Recovering oil by injecting aqueous alkali, cosurfactant and gas

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

Reisberg, J.; Bielmowicz, L. J.; Thigpen, D. R.

1985-01-15

A process of recovering oil from a subterranean reservoir in which the oil is acidic but forms monovalent cation soaps of only relatively low interfacial activity when reacted with aqueous alkaline solutions, comprises displacing the oil toward a production location with a mixture of gas and cosurfactant-containing aqueous alkaline solution.

Quantitative Characterization of Aqueous Byproducts from Hydrothermal Liquefaction of Municipal Wastes, Food Industry Wastes, and Biomass Grown on Waste

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

Maddi, Balakrishna; Panisko, Ellen; Wietsma, Thomas

Hydrothermal liquefaction (HTL) is a viable thermochemical process for converting wet solid wastes into biocrude which can be hydroprocessed to liquid transportation fuel blendstocks and specialty chemicals. The aqueous byproduct from HTL contains significant amounts (20 to 50%) of the feed carbon, which must be used to enhance economic sustainability of the process on an industrial scale. In this study, aqueous fractions produced from HTL of industrial and municipal waste were characterized using a wide variety of analytical approaches. Organic chemical compounds present in these aqueous fractions were identified using two-dimensional gas chromatography equipped with time-of-flight mass spectrometry. Identified compoundsmore » include organic acids, nitrogen compounds, alcohols, aldehydes, and ketones. Conventional gas chromatography and liquid chromatography methods were employed to quantify the identified compounds. Inorganic species, in the aqueous stream of hydrothermal liquefaction of these aqueous byproducts, also were quantified using ion chromatography and inductively coupled plasma optical emission spectroscopy. The concentrations of organic chemical compounds and inorganic species are reported, and the significance of these results is discussed in detail.« less

Origin and Evolution of Prebiotic Organic Matter as Inferred from the Tagish Lake Meteorite

NASA Technical Reports Server (NTRS)

Herd, Christopher D.; Blinova, Alexandra; Simkus, Danielle N.; Huang, Yongsong; Tarozo, Rafael; Alexander, Conel M.; Gyngard, Frank; Nittler, Larry R.; Cody, George D.; Fogel, Marilyn L.;

Effect of UV-A and UV-B irradiation on the metabolic profile of aqueous humor in rabbits analyzed by 1H NMR spectroscopy.

PubMed

Tessem, May-Britt; Bathen, Tone F; Cejková, Jitka; Midelfart, Anna

2005-03-01

This study was conducted to investigate metabolic changes in aqueous humor from rabbit eyes exposed to either UV-A or -B radiation, by using (1)H nuclear magnetic resonance (NMR) spectroscopy and unsupervised pattern recognition methods. Both eyes of adult albino rabbits were irradiated with UV-A (366 nm, 0.589 J/cm(2)) or UV-B (312 nm, 1.667 J/cm(2)) radiation for 8 minutes, once a day for 5 days. Three days after the last irradiation, samples of aqueous humor were aspirated, and the metabolic profiles analyzed with (1)H NMR spectroscopy. The metabolic concentrations in the exposed and control materials were statistically analyzed and compared, with multivariate methods and one-way ANOVA. UV-B radiation caused statistically significant alterations of betaine, glucose, ascorbate, valine, isoleucine, and formate in the rabbit aqueous humor. By using principal component analysis, the UV-B-irradiated samples were clearly separated from the UV-A-irradiated samples and the control group. No significant metabolic changes were detected in UV-A-irradiated samples. This study demonstrates the potential of using unsupervised pattern recognition methods to extract valuable metabolic information from complex (1)H NMR spectra. UV-B irradiation of rabbit eyes led to significant metabolic changes in the aqueous humor detected 3 days after the last exposure.

Physicochemical processes in the indirect interaction between surface air plasma and deionized water

NASA Astrophysics Data System (ADS)

Liu, Z. C.; Liu, D. X.; Chen, C.; Li, D.; Yang, A. J.; Rong, M. Z.; Chen, H. L.; Kong, M. G.

2015-12-01

One of the most central scientific questions for plasma applications in healthcare and environmental remediation is the chemical identity and the dose profile of plasma-induced reactive oxygen and nitrogen species (ROS/RNS) that can act on an object inside a liquid. A logical focus is on aqueous physicochemical processes near a sample with a direct link to their upstream gaseous processes in the plasma region and a separation gap from the liquid bulk. Here, a system-level modeling framework is developed for indirect interactions of surface air plasma and a deionized water bulk and its predictions are found to be in good agreement with the measurement of gas-phase ozone and aqueous long-living ROS/RNS concentrations. The plasma region is described with a global model, whereas the air gap and the liquid region are simulated with a 1D fluid model. All three regions are treated as one integrated entity and computed simultaneously. With experimental validation, the system-level modeling shows that the dominant aqueous ROS/RNS are long-living species (e.g. H2O2 aq, O3 aq, nitrite/nitrate, H+ aq). While most short-living gaseous species could hardly survive their passage to the liquid, aqueous short-living ROS/RNS are generated in situ through reactions among long-living plasma species and with water molecules. This plasma-mediated remote production of aqueous ROS/RNS is important for the abundance of aqueous HO2 aq, HO3 aq, OHaq and \\text{O}2- aq as well as NO2 aq and NO3 aq. Aqueous plasma chemistry offers a novel and significant pathway to activate a given biological outcome, as exemplified here for bacterial deactivation in plasma-activated water. Additional factors that may synergistically broaden the usefulness of aqueous plasma chemistry include an electric field by aqueous ions and liquid acidification. The system-modeling framework will be useful in assisting designs and analyses of future investigations of plasma-liquid and plasma-cell interactions.

Attenuated Total Reflection Fourier Transform Infrared (ATR FT-IR) Spectroscopy as an Analytical Method to Investigate the Secondary Structure of a Model Protein Embedded in Solid Lipid Matrices.

PubMed

Zeeshan, Farrukh; Tabbassum, Misbah; Jorgensen, Lene; Medlicott, Natalie J

2018-02-01

Protein drugs may encounter conformational perturbations during the formulation processing of lipid-based solid dosage forms. In aqueous protein solutions, attenuated total reflection Fourier transform infrared (ATR FT-IR) spectroscopy can investigate these conformational changes following the subtraction of spectral interference of solvent with protein amide I bands. However, in solid dosage forms, the possible spectral contribution of lipid carriers to protein amide I band may be an obstacle to determine conformational alterations. The objective of this study was to develop an ATR FT-IR spectroscopic method for the analysis of protein secondary structure embedded in solid lipid matrices. Bovine serum albumin (BSA) was chosen as a model protein, while Precirol AT05 (glycerol palmitostearate, melting point 58 ℃) was employed as the model lipid matrix. Bovine serum albumin was incorporated into lipid using physical mixing, melting and mixing, or wet granulation mixing methods. Attenuated total reflection FT-IR spectroscopy and size exclusion chromatography (SEC) were performed for the analysis of BSA secondary structure and its dissolution in aqueous media, respectively. The results showed significant interference of Precirol ATO5 with BSA amide I band which was subtracted up to 90% w/w lipid content to analyze BSA secondary structure. In addition, ATR FT-IR spectroscopy also detected thermally denatured BSA solid alone and in the presence of lipid matrix indicating its suitability for the detection of denatured protein solids in lipid matrices. Despite being in the solid state, conformational changes occurred to BSA upon incorporation into solid lipid matrices. However, the extent of these conformational alterations was found to be dependent on the mixing method employed as indicated by area overlap calculations. For instance, the melting and mixing method imparted negligible effect on BSA secondary structure, whereas the wet granulation mixing method promoted more changes. Size exclusion chromatography analysis depicted the complete dissolution of BSA in the aqueous media employed in the wet granulation method. In conclusion, an ATR FT-IR spectroscopic method was successfully developed to investigate BSA secondary structure in solid lipid matrices following the subtraction of lipid spectral interference. The ATR FT-IR spectroscopy could further be applied to investigate the secondary structure perturbations of therapeutic proteins during their formulation development.

Preparing polymeric matrix composites using an aqueous slurry technique

NASA Technical Reports Server (NTRS)

Johnston, Norman J. (Inventor); Towell, Timothy W. (Inventor)

1993-01-01

An aqueous process was developed to prepare a consolidated composite laminate from an aqueous slurry. An aqueous poly(amic acid) surfactant solution was prepared by dissolving a poly(amic acid) powder in an aqueous ammonia solution. A polymeric powder was added to this solution to form a slurry. The slurry was deposited on carbon fiber to form a prepreg which was dried and stacked to form a composite laminate. The composite laminate was consolidated using pressure and was heated to form the polymeric matrix. The resulting composite laminate exhibited high fracture toughness and excellent consolidation.

A framework for expanding aqueous chemistry in the Community Multiscale Air Quality (CMAQ) model version 5.1

NASA Astrophysics Data System (ADS)

Fahey, Kathleen M.; Carlton, Annmarie G.; Pye, Havala O. T.; Baek, Jaemeen; Hutzell, William T.; Stanier, Charles O.; Baker, Kirk R.; Wyat Appel, K.; Jaoui, Mohammed; Offenberg, John H.

2017-04-01

This paper describes the development and implementation of an extendable aqueous-phase chemistry option (AQCHEM - KMT(I)) for the Community Multiscale Air Quality (CMAQ) modeling system, version 5.1. Here, the Kinetic PreProcessor (KPP), version 2.2.3, is used to generate a Rosenbrock solver (Rodas3) to integrate the stiff system of ordinary differential equations (ODEs) that describe the mass transfer, chemical kinetics, and scavenging processes of CMAQ clouds. CMAQ's standard cloud chemistry module (AQCHEM) is structurally limited to the treatment of a simple chemical mechanism. This work advances our ability to test and implement more sophisticated aqueous chemical mechanisms in CMAQ and further investigate the impacts of microphysical parameters on cloud chemistry. Box model cloud chemistry simulations were performed to choose efficient solver and tolerance settings, evaluate the implementation of the KPP solver, and assess the direct impacts of alternative solver and kinetic mass transfer on predicted concentrations for a range of scenarios. Month-long CMAQ simulations for winter and summer periods over the US reveal the changes in model predictions due to these cloud module updates within the full chemical transport model. While monthly average CMAQ predictions are not drastically altered between AQCHEM and AQCHEM - KMT, hourly concentration differences can be significant. With added in-cloud secondary organic aerosol (SOA) formation from biogenic epoxides (AQCHEM - KMTI), normalized mean error and bias statistics are slightly improved for 2-methyltetrols and 2-methylglyceric acid at the Research Triangle Park measurement site in North Carolina during the Southern Oxidant and Aerosol Study (SOAS) period. The added in-cloud chemistry leads to a monthly average increase of 11-18 % in cloud SOA at the surface in the eastern United States for June 2013.

Crataegus monogyna fruit aqueous extract as a protective agent against doxorubicin-induced reproductive toxicity in male rats

PubMed Central

Shalizar Jalali, Ali; Hasanzadeh, Shapour

2013-01-01

Objective: Doxorubicin (DOX) is a broad spectrum chemotherapeutic agent used in the treatment of several malignancies. The use of DOX in clinical chemotherapy has been restricted due to its diverse toxicities, including reproductive toxicity. Crataegus monogyna (C. monogyna) is one of the oldest medicinal plants that have been shown to be cytoprotective because of scavenging free radicals. The present study was undertaken to determine whether C. monogyna fruits aqueous extract could serve as a protective agent against reproductive toxicity during DOX treatment in a rat model through antioxidant-mediated mechanisms. Materials and Methods: Male Wistar rats were allocated to four groups. Two groups of rats were treated with DOX at a dose of 4 mg/kg intraperitoneally on days 1, 7, 14, 21, and 28 (accumulated dose of 20 mg/kg). One of the groups received C. monogyna fruits aqueous extract at a dose of 20 mg/kg per day orally for 28 days along with DOX. A vehicle-treated control group and a C. monogyna control group were also included. Results: The DOX-treated group showed significant decreases in the body and organ weights and spermatogenic activities as well as many histological alterations. DOX treatment also caused a significant decrease in sperm count and motility with an increase in dead and abnormal sperms. Moreover, significant decrease in serum levels of testosterone and increased serum concentrations of FSH, LH, LDH, CPK, and SGOT were observed in DOX-treated rats. Notably, Crataegus co-administration caused a partial recovery in above-mentioned parameters. Conclusion: These findings indicated that doxorubicin can adversely damage the testicular tissue, while Crataegus co-administration could effectively prevent these adverse effects by effective inhibiting oxidative processes and restoration of antioxidant defense system. PMID:25050270

Reaction behaviors of decomposition of monocrotophos in aqueous solution by UV and UV/O processes.

PubMed

Ku, Y; Wang, W; Shen, Y S

2000-02-01

The decomposition of monocrotophos (cis-3-dimethoxyphosphinyloxy-N-methyl-crotonamide) in aqueous solution by UV and UV/O(3) processes was studied. The experiments were carried out under various solution pH values to investigate the decomposition efficiencies of the reactant and organic intermediates in order to determine the completeness of decomposition. The photolytic decomposition rate of monocrotophos was increased with increasing solution pH because the solution pH affects the distribution and light absorbance of monocrotophos species. The combination of O(3) with UV light apparently promoted the decomposition and mineralization of monocrotophos in aqueous solution. For the UV/O(3) process, the breakage of the >C=C< bond of monocrotophos by ozone molecules was found to occur first, followed by mineralization by hydroxyl radicals to generate CO(3)(2-), PO4(3-), and NO(3)(-) anions in sequence. The quasi-global kinetics based on a simplified consecutive-parallel reaction scheme was developed to describe the temporal behavior of monocrotophos decomposition in aqueous solution by the UV/O(3) process.

Interactions of silicate glasses with aqueous environments under conditions of prolonged contact and flow

NASA Technical Reports Server (NTRS)

Barkatt, Aaron; Saad, E. E.; Adiga, R. B.; Sousanpour, W.; Barkatt, AL.; Feng, X.; O'Keefe, J. A.; Alterescu, S.

1988-01-01

This paper discusses mechanisms involving saturation and reactions that lead to the formation of altered phases in silicate glasses considered for use in geologic repositories for nuclear waste. It is shown that the rate of dissolution of silicate glasses exposed to a broad range of contact times, leachant compositions, and surface-to-volume ratios is strongly affected by the presence of reactive species such as Al, Mg, and Fe. The reactive materials may originate in the leachant or, under conditions of high surface-to-volume ratio, in the glass itself. The effects of glass composition on the course of the corrosion process can be viewed in terms of the formation of a surface layer on the leached glass; the type, composition, and structure of this layer control the dissolution behavior of the glass.

R Raman Spectroscopy and Petrology of Antarctic CR Chondrites: Comparison with Other Carbonaceous Chondrites

NASA Technical Reports Server (NTRS)

Komatsu, M.; Fagan, T. J.; Yamaguchi, A.; Mikouchi, T.; Zolensky, M. E.; Yasutake, M.

2015-01-01

In Renazzo-like carbonaceous (CR) chondrites, abundant original Fe,Ni-metal is preserved in chrondules, but the matrix is characterized by fine-grained magnetite with phyllosilicate. This combination of reduced Fe in chrodrules with oxidized Fe and phyllosilicate in the matrix has been attributed to aqueous alteration of matrix at relatively low temperatures.

Determining Changes in Groundwater Quality during Managed Aquifer Recharge

NASA Astrophysics Data System (ADS)

Gambhir, T.; Houlihan, M.; Fakhreddine, S.; Dadakis, J.; Fendorf, S. E.

2016-12-01

Managed aquifer recharge (MAR) is becoming an increasingly prevalent technology for improving the sustainability of freshwater supply. However, recharge water can alter the geochemical conditions of the aquifer, mobilizing contaminants native to the aquifer sediments. Geochemical alterations on deep (>300 m) injection of highly treated recycled wastewater for MAR has received limited attention. We aim to determine how residual disinfectants used in water treatment processes, specifically the strong oxidants chloramine and hydrogen peroxide, affect metal mobilization within deep injection wells of the Orange County Water District. Furthermore, as the treated recharge water has very low ionic strength (44.6 mg L-1 total dissolved solids), we tested how differing concentrations of magnesium chloride and calcium chloride affected metal mobilization within deep aquifers. Continuous flow experiments were conducted on columns dry packed with sediments from a deep injection MAR site in Orange County, CA. The effluent was analyzed for shifts in water quality, including aqueous concentrations of arsenic, uranium, and chromium. Interaction between the sediment and oxic recharge solution causes naturally-occurring arsenopyrite to repartition onto iron oxides. The stability of arsenic on the newly precipitated iron oxides is dependent on pH changes during recharge.

Surface modification of zinc oxide nanoparticle by PMAA and its dispersion in aqueous system

NASA Astrophysics Data System (ADS)

Tang, Erjun; Cheng, Guoxiang; Ma, Xiaolu; Pang, Xingshou; Zhao, Qiang

2006-05-01

Commercial zinc oxide nanoparticles were modified by polymethacrylic acid (PMAA) in aqueous system. The hydroxyl groups of nano-ZnO particle surface can interact with carboxyl groups (COO-) of PMAA and form poly(zinc methacrylate) complex on the surface of nano-ZnO. The formation of poly(zinc methacrylate) complex was testified by Fourier-transform infrared spectra (FT-IR). Thermogravimetric analysis (TGA) indicated that PMAA molecules were absorbed or anchored on the surface of nano-ZnO particle, which facilitated to hinder the aggregation of nano-ZnO particles. Through particle size analysis and transmission electron micrograph (TEM) observation, it was found that PMAA enhanced the dispersibility of nano-ZnO particles in water. The dispersion stabilization of modified ZnO nanoparticles in aqueous system was significantly improved due to the introduction of grafted polymer on the surface of nanoparticles. The modification did not alter the crystalline structure of the ZnO nanoparticles according to the X-ray diffraction patterns.

Process of concentrating ethanol from dilute aqueous solutions thereof

DOEpatents

Oulman, C.S.; Chriswell, C.D.

1981-07-07

Relatively dilute aqueous solutions of ethanol are concentrated by passage through a bed of a crystalline silica polymorph, such as silicalite, to adsorb the ethanol with residual dilute feed in contact with the bed, which is displaced by passing concentrated aqueous ethanol through the bed without displacing the adsorbed ethanol. A product concentrate is then obtained by removing the adsorbed ethanol from the bed together with at least a portion of the concentrated aqueous ethanol used as the displacer liquid. This process permits ethanol to be concentrated from dilute fermentation beers, which may contain from 6 to 10% ethanol, to obtain a concentrate product at very low energy cost having an ethanol concentration in excess of 95%, such as a concentration of from 98 to 99.5%. 5 figs.

Process of concentrating ethanol from dilute aqueous solutions thereof

DOEpatents

Oulman, Charles S. [Ames, IA; Chriswell, Colin D. [Slater, IA

1981-07-07

Relatively dilute aqueous solutions of ethanol are concentrated by passage through a bed of a crystalline silica polymorph, such as silicalite, to adsorb the ethanol with residual dilute feed in contact with the bed, which is displaced by passing concentrated aqueous ethanol through the bed without displacing the adsorbed ethanol. A product concentrate is then obtained by removing the adsorbed ethanol from the bed together with at least a portion of the concentrated aqueous ethanol used as the displacer liquid. This process permits ethanol to be concentrated from dilute fermentation beers, which may contain from 6 to 10% ethanol, to obtain a concentrate product at very low energy cost having an ethanol concentration in excess of 95%, such as a concentration of from 98 to 99.5%.

Flexible ITO-free organic solar cells applying aqueous solution-processed V2O5 hole transport layer: An outdoor stability study

NASA Astrophysics Data System (ADS)

Lima, F. Anderson S.; Beliatis, Michail J.; Roth, Bérenger; Andersen, Thomas R.; Bortoti, Andressa; Reyna, Yegraf; Castro, Eryza; Vasconcelos, Igor F.; Gevorgyan, Suren A.; Krebs, Frederik C.; Lira-Cantu, Mónica

2016-02-01

Solution processable semiconductor oxides have opened a new paradigm for the enhancement of the lifetime of thin film solar cells. Their fabrication by low-cost and environmentally friendly solution-processable methods makes them ideal barrier (hole and electron) transport layers. In this work, we fabricate flexible ITO-free organic solar cells (OPV) by printing methods applying an aqueous solution-processed V2O5 as the hole transport layer (HTL) and compared them to devices applying PEDOT:PSS. The transparent conducting electrode was PET/Ag/PEDOT/ZnO, and the OPV configuration was PET/Ag/PEDOT/ZnO/P3HT:PC60BM/HTL/Ag. Outdoor stability analyses carried out for more than 900 h revealed higher stability for devices fabricated with the aqueous solution-processed V2O5.

Extracting alcohols from aqueous solutions. [USDOE patent application

DOEpatents

Compere, A.L.; Googin, J.M.; Griffith, W.L.

1981-12-02

The objective is to provide an efficient process for extracting alcohols in aqueous solutions into hydrocarbon fuel mixtures, such as gasoline, diesel fuel and fuel oil. This is done by contacting an aqueous fermentation liquor with a hydrocarbon or hydrocarbon mixture containing carbon compounds having 5-18 carbon atoms, which may include gasoline, diesel fuel or fuel oil. The hydrocarbon-aqueous alcohol solution is then mixed with one or more of a group of polyoxyalkylene polymers to extract the alcohol into the hydrocarbon fuel-polyoxyalkylene polymer mixture.

Petrologic evolution of CM chondrites: The difficulty of discriminating between nebular and parent-body effects

NASA Astrophysics Data System (ADS)

Kerridge, J. F.; McSween, H. Y., Jr.; Bunch, T. E.

1994-07-01

We wish to draw attention to a major controversy that has arisen in the area of CM-chondrite petrology. The problem is important because its resolution will have profound implications for ideas concerning nebular dynamics, gas-solid interactions in the nebula, and accretionary processes in the nebula, among other issues. On the one hand, cogent arguments have been presented that 'accretionary dust mantles,' were formed in the solar nebula prior to accretion of the CM parent asteroid(s). On the other hand, no-less-powerful arguments have been advanced that a significant fraction of the CM lithology is secondary, produced by aqueous alteration in the near-surface regions of an asteroid-sized object. Because most, if not all, CM chondrites are breccias, these two views could coexist harmoniously, were it not for the fact that some of the coarse-grained lithologies surrounded by 'accretion dust mantles' are themselves of apparently secondary origin. Such an observation must clearly force a reassessment of one or both of the present schools of thought. Our objective here is to stimulate such a reassessment. Four possible resolutions of this conflict may be postulated. First, perhaps nature found a way of permitting such secondary alteration to take place in the nebula. Second, maybe dust mantles could form in a regolith, rather than a nebular, environment. Third, it is possible that dust mantles around secondary lithologies are different from those around primary lithologies. Finally, perhaps formation of CM chondrites involved a more complex sequence of events than visualized so far, so that some apparently 'primary' processes postdated certain 'secondary' processes.

Evidence for mechanical and chemical alteration of iron-nickel meteorites on Mars: Process insights for Meridiani Planum

USGS Publications Warehouse

Ashley, James W.; Golombek, M.P.; Christensen, P.R.; Squyres, S. W.; McCoy, T.J.; Schroder, C.; Fleischer, I.; Johnson, J. R.; Herkenhoff, K. E.; Parker, T.J.

2011-01-01

The weathering of meteorites found on Mars involves chemical and physical processes that can provide clues to climate conditions at the location of their discovery. Beginning on sol 1961, the Opportunity rover encountered three large iron meteorites within a few hundred meters of each other. In order of discovery, these rocks have been assigned the unofficial names Block Island, Shelter Island, and Mackinac Island. Each rock presents a unique but complimentary set of features that increase our understanding of weathering processes at Meridiani Planum. Significant morphologic characteristics interpretable as weathering features include (1) a large pit in Block Island, lined with delicate iron protrusions suggestive of inclusion removal by corrosive interaction; (2) differentially eroded kamacite and taenite lamellae in Block Island and Shelter Island, providing relative timing through crosscutting relationships with deposition of (3) an iron oxide-rich dark coating; (4) regmaglypted surfaces testifying to regions of minimal surface modification, with other regions in the same meteorites exhibiting (5) large-scale, cavernous weathering (in Shelter Island and Mackinac Island). We conclude that the current size of the rocks is approximate to their original postfall contours. Their morphology thus likely results from a combination of atmospheric interaction and postfall weathering effects. Among our specific findings is evidence supporting (1) at least one possible episode of aqueous acidic exposure for Block Island; (2) ripple migration over portions of the meteorites; (3) a minimum of two separate episodes of wind abrasion; alternating with (4) at least one episode of coating-forming chemical alteration, most likely at subzero temperatures. Copyright 2011 by the American Geophysical Union.

Comparison of fluoride intercalation/de-intercalation processes on graphite electrodes in aqueous and aqueous methanolic HF media

NASA Astrophysics Data System (ADS)

Noel, M.; Santhanam, R.; Francisca Flora, M.

The solvent can play a major role in the intercalation/de-intercalation process and the stability of graphite substrates towards this process. This fact is established in the present work that involves fluoride intercalation/de-intercatlation on graphite electrodes in aqueous and aqueous methanolic HF solutions where the HF concentration is varied between 1.0 and 18.0 M. In addition to cyclic voltammetry and potentiostatic polarization, open-circuit potential decay measurements, scanning electron microscopy and X-ray diffraction measurements have been employed. In general, addition of methanol and increasing concentration of HF raise the overall intercalation/de-intercalation efficiency. Methanol is adsorbed preferentially on the graphite lattice and, hence, suppresses both oxygen evolution and the formation of passive graphite oxides. In 15.0 M HF, the optimum methanol concentration is 5 vol.%. This suggests that, in addition to the adsorption effect, there is some weakening of the structured water molecules that facilitates the solvated fluoride ions for efficient intercalation.

Coupling hydrothermal liquefaction and anaerobic digestion for energy valorization from model biomass feedstocks.

PubMed

Posmanik, Roy; Labatut, Rodrigo A; Kim, Andrew H; Usack, Joseph G; Tester, Jefferson W; Angenent, Largus T

2017-06-01

Hydrothermal liquefaction converts food waste into oil and a carbon-rich hydrothermal aqueous phase. The hydrothermal aqueous phase may be converted to biomethane via anaerobic digestion. Here, the feasibility of coupling hydrothermal liquefaction and anaerobic digestion for the conversion of food waste into energy products was examined. A mixture of polysaccharides, proteins, and lipids, representing food waste, underwent hydrothermal processing at temperatures ranging from 200 to 350°C. The anaerobic biodegradability of the hydrothermal aqueous phase was examined through conducting biochemical methane potential assays. The results demonstrate that the anaerobic biodegradability of the hydrothermal aqueous phase was lower when the temperature of hydrothermal processing increased. The chemical composition of the hydrothermal aqueous phase affected the anaerobic biodegradability. However, no inhibition of biodegradation was observed for most samples. Combining hydrothermal and anaerobic digestion may, therefore, yield a higher energetic return by converting the feedstock into oil and biomethane. Copyright © 2017 Elsevier Ltd. All rights reserved.

SOLVENT EXTRACTION PROCESS FOR THE SEPARATION OF URANIUM AND THORIUM FROM PROTACTINIUM AND FISSION PRODUCTS

DOEpatents

Rainey, R.H.; Moore, J.G.

1962-08-14

A liquid-liquid extraction process was developed for recovering thorium and uranium values from a neutron irradiated thorium composition. They are separated from a solvent extraction system comprising a first end extraction stage for introducing an aqueous feed containing thorium and uranium into the system consisting of a plurality of intermediate extractiorr stages and a second end extractron stage for introducing an aqueous immiscible selective organic solvent for thorium and uranium in countercurrent contact therein with the aqueous feed. A nitrate iondeficient aqueous feed solution containing thorium and uranium was introduced into the first end extraction stage in countercurrent contact with the organic solvent entering the system from the second end extraction stage while intro ducing an aqueous solution of salting nitric acid into any one of the intermediate extraction stages of the system. The resultant thorium and uranium-laden organic solvent was removed at a point preceding the first end extraction stage of the system. (AEC)

Process for extracting technetium from alkaline solutions

DOEpatents

Moyer, Bruce A.; Sachleben, Richard A.; Bonnesen, Peter V.

1995-01-01

A process for extracting technetium values from an aqueous alkaline solution containing at least one alkali metal hydroxide and at least one alkali metal nitrate, the at least one alkali metal nitrate having a concentration of from about 0.1 to 6 molar. The solution is contacted with a solvent consisting of a crown ether in a diluent for a period of time sufficient to selectively extract the technetium values from the aqueous alkaline solution. The solvent containing the technetium values is separated from the aqueous alkaline solution and the technetium values are stripped from the solvent.

Bidentate organophosphorus solvent extraction process for actinide recovery and partition

DOEpatents

Schulz, Wallace W.

1976-01-01

A liquid-liquid extraction process for the recovery and partitioning of actinide values from acidic nuclear waste aqueous solutions, the actinide values including trivalent, tetravalent and hexavalent oxidation states is provided and includes the steps of contacting the aqueous solution with a bidentate organophosphorous extractant to extract essentially all of the actinide values into the organic phase. Thereafter the respective actinide fractions are selectively partitioned into separate aqueous solutions by contact with dilute nitric or nitric-hydrofluoric acid solutions. The hexavalent uranium is finally removed from the organic phase by contact with a dilute sodium carbonate solution.

A process for the preparation of cysteine from cystine

DOEpatents

Chang, Shih-Ger; Liu, David K.; Griffiths, Elizabeth A.; Littlejohn, David

1989-01-01

The present invention in one aspect relates to a process for the simultaneous removal of NO.sub.x and SO.sub.2 from a fluid stream comprising mixtures thereof and in another aspect relates to the separation, use and/or regeneration of various chemicals contaminated or spent in the process and which includes the steps of: (A) contacting the fluid stream at a temperature of between about 105.degree. and 180.degree. C. with a liquid aqueous slurry or solution comprising an effective amount of an iron chelate of an amino acid moiety having at least one --SH group; (B) separating the fluid stream from the particulates formed in step (A) comprising the chelate of the amino acid moiety and fly ash; (C) washing and separating the particulates of step (B) with an aqeous solution having a pH value of between about 5 to 8; (D) subsequently washing and separating the particulates of step (C) with a strongly acidic aqueous solution having a pH value of between about 1 to 3; (E) washing and separating the particulates of step (D) with an basic aqueous solution having a pH value of between about 9 to 12; (F) optionally adding additional amino acid moiety, iron (II) and alkali to the aqueous liquid from step (D) to produce an aqueous solution or slurry similar to that in step (A) having a pH value of between about 4 to 12; and (G) recycling the aqueous slurry of step (F) to the contacting zone of step (A). Steps (D) and (E) can be carried out in the reverse sequence, however the preferred order is (D) and then (E). In a preferred embodiment the present invention provides an improved process for the preparation (regeneration) of cysteine from cystine, which includes reacting an aqueous solution of cystine at a pH of between about 9 to 13 with a reducing agent selected from hydrogen sulfide or alkali metal sulfides, sulfur dioxide, an alkali metal sulfite or mixtures thereof for a time and at a temperature effective to cleave and reduce the cystine to cysteine with subsequent recovery of the cysteine. In another preferred embodiment the present invention provides a process for the removal of NO.sub.x, SO.sub.2 and particulates from a fluid stream which includes the steps of (A) injecting into a reaction zone an aqueous solution itself comprising (i) an amino acid moiety selected from those described above; (ii) iron (II) ion; and (iii) an alkali, wherein the aqueous solution has a pH of between about 4 and 11; followed by solids separation and washing as is described in steps (B), (C), (D) and (E) above. The overall process is useful to reduce acid rain components from combustion gas sources.

Anterior Segment Alterations and Comparative Aqueous Humor Proteomics in the Buphthalmic Rabbit (An American Ophthalmological Society Thesis)

PubMed Central

Edward, Deepak P.; Bouhenni, Rachida

2011-01-01

Purpose To use an integrated proteohistologic approach to gain insight into the anterior segment alterations in the buphthalmic rabbit. Methods Eyes from 2- and 5-year-old buphthalmic and normal rabbits (n=20) were studied histologically. Liquid chromatography–tandem mass spectrometry (LC-MS/MS) of aqueous humor (AH) was used to determine differential protein expression between animal groups. Western blot and immunohistochemistry were performed on selected differentially expressed proteins identified by LC-MS/MS. Results The buphthalmic rabbits manifested a mild clinical phenotype with typical angle anomalies that appeared progressive by histology. Significantly thickened Descemet’s membrane (DM) and anterior lens capsule in all buphthalmic rabbits showed increased fibronectin and collagen-IV immunolabeling. LC-MS/MS applying stringent filtering criteria revealed significant differential expression of several AH proteins in these rabbits. The protein of interest in the 2-year-old group was histidine-rich glycoprotein, and those in the 5-year-old group included alpha-2-HS-glycoprotein, clusterin, apolipoprotein E, interphotoreceptor retinoid-binding protein, transthyretin, cochlin, gelsolin, haptoglobin, hemopexin, and beta-2 microglobulin. The proteomic data for selected proteins was validated by Western blot and immunohistochemistry. A wide range of functional groups were affected by the altered AH proteins. These included extracellular matrix modulation, regulation of apoptosis, oxidative stress, and protein transport. Conclusions Multiple anterior segment alterations were histologically identified in the buphthalmic rabbits that showed progressive changes with age. The differentially expressed AH proteins in these rabbits suggest a multifunctional role for AH in modulating pathologic changes in DM, anterior lens capsule, and the angular meshwork in these animals. PMID:22253484

The effects of wine-processing on ascending and descending: The distribution of flavonoids in rat tissues after oral administration of crude and wine-processed Radix scutellariae.

PubMed

Huang, Ping; Tan, Shanzhong; Zhang, Yong-xin; Li, Jun-song; Chai, Chuan; Li, Jin-ji; Cai, Bao-chang

2014-08-08

Ascending and descending theory is a core principle of traditional Chinese medicine (TCM) theories. It plays an essential role in TCM clinical applications. Some TCM medicine has specific properties, which could alter the inclination and direction of their actions. The properties of the ascending and floating process of one herbal medicine are affected by means of herb processing. Wine-processing, which is sautéing with rice wine, is one of the most popular technologies of herb processing. Wine-processing increases the inclination and direction of its actions, thereby producing or strengthening their efficacy in cleaning the upper-energizer heat. Radix scutellariae, the dried roots of Scutellaria baicalensis Georgi, is a well-known TCM used for the treatment of inflammation, pyrexia, jaundice, etc. Recently, wine-processed Radix scutellariae was normally applied in clinical studies for the treatment of upper-energizer syndrome. In order to investigate the effects of wine-processing on ascending and descending of Radix scutellariae, the comparative study of distribution of flavonoids in rat tissues of triple energizers (SanJiao-upper, middle, lower jiao) after oral administration of crude and wine-processed Radix scutellariae aqueous extracts was carried out. The rats were randomly assigned to two groups and orally administered with crude and wine-processed Radix scutellariae aqueous extracts, respectively. At different pre-determined time points after administration, the concentrations of compounds in rat tissue homogenate were determined, and the main tissue pharmacokinetic parameters were investigated. Tissue pharmacokinetic parameters including AUC0-t, t1/2, Tmax and Cmax were calculated using DAS 2.0. An unpaired Student t-test was used to compare the differences in tissue pharmacokinetic parameters between the two groups. All the results were expressed as arithmetic mean±S.D. The parameters of Cmax and AUC0-t of some flavonoids in wine-processed Radix scutellariae were remarkably increased (p<0.05, p<0.01, p<0.001) in the rat upper-energizer tissues (lung and heart) compared with those of the crude group. However, in the rat middle- and lower-energizer tissues (spleen, liver and kidney), the Cmax and AUC0-t of some flavonoids were significantly decreased (p<0.05, p<0.01) compared with the crude group. The main explanation for these differences seems to the effects of wine-processing on ascending and descending theory. All of these differences in the distribution of triple energizers after oral administration of crude and wine-processed Radix scutellariae aqueous extracts may lead to the increase of efficacy on the upper-energizer tissues and were in compliance with the ascending and descending theory. Therefore, wine-processing was recommended when Radix scutellariae was used for cleaning the upper-energizer heat and humidity. The obtained knowledge can be used to evaluate the impact of these differences on the efficacy of both the drugs in clinical applications and might be helpful in explaining the effects of wine-processing on ascending and descending theory. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

A Systematic Evaluation of the Extent of Photochemical Processing in Different Types of Secondary Organic Aerosols in the Aqueous Phase

NASA Astrophysics Data System (ADS)

Romonosky, D.; Lee, H.; Epstein, S. A.; Nizkorodov, S.; Laskin, J.; Laskin, A.

2013-12-01

A significant fraction of atmospheric organic compounds are predominantly found in condensed phases, such as organic phase in aerosol particles or aqueous phase in cloud droplets. The oxidation of VOCs followed by the condensation of products into particles was thought to be the main mechanism of organic aerosol (OA) formation. However, in the last several years, scientists have realized that a large fraction, if not the majority of organic particles, is produced through cloud and fog photochemical processes. Many of these organic compounds are photolabile, and can degrade through direct photolysis or indirect photooxidation processes on time scales that are comparable to the typical lifetimes of droplets (hours) and particles (days). We previously reported that compounds in secondary organic aerosol (SOA) from ozonolysis of d-limonene efficiently photodegrade in both organic (Walser et al., 2007) and aqueous phases (Bateman et al., 2011). Significant photolysis was also observed in an aqueous extract of SOA from high-NOx photooxidation of isoprene (Nguyen et al., 2012). More recent experiments studying the response to irradiation of complex aqueous mixtures (as opposed to solutions of isolated compounds) found surprising resilience to photodegradation in aqueous extracts of SOA prepared by photooxidation of alpha-pinene (Romonosky et al., unpublished). We present a systematic investigation of the extent of photochemical processing in different types of SOA from various biogenic and anthropogenic precursors. Chamber- or flowtube-generated SOA is collected on an inert substrate, extracted in a methanol/water solution (70:30), photolyzed in the aqueous solution, and the extent of change in the molecular level composition of the material is assessed with high-resolution mass spectrometry (HR-MS). The outcome of this study will be improved understanding of the role of condensed-phase photochemistry in chemical aging of aerosol particles and cloud droplets. Bateman et al. Photolytic processing of secondary organic aerosols dissolved in cloud droplets. Phys. Chem. Chem. Phys. 2011, 13, 12199. Nguyen et al. Direct aqueous photochemistry of isoprene high-NOx secondary organic aerosol. Phys. Chem. Chem. Phys. 2012, 14, 9702. Walser et al. Photochemical aging of secondary organic aerosol particles generated from the oxidation of d-limonene. J. Phys. Chem. A 2007, 111, 1907.

INVESTIGATION OF AQUEOUS BIPHASIC SYSTEMS FOR THE SEPARATIONS OF LIGNINS FROM CELLULOSE IN THE PAPER PULPING PROCESS. (R826732)

EPA Science Inventory

In efforts to apply a polymer-based aqueous biphasic system (ABS) extraction to the paper pulping process, the study of the distribution of various lignin and cellulosic fractions in ABS and the effects of temperature on system composition and solute partitioning have been inv...

In Situ Coating of Li[Ni0.33 Mn0.33 Co0.33 ]O2 Particles to Enable Aqueous Electrode Processing.

PubMed

Loeffler, Nicholas; Kim, Guk-Tae; Mueller, Franziska; Diemant, Thomas; Kim, Jae-Kwang; Behm, R Jürgen; Passerini, Stefano

2016-05-23

The aqueous processing of lithium-ion battery (LIB) electrodes has the potential to notably decrease the battery processing costs and paves the way for a sustainable and environmentally benign production (and recycling) of electrochemical energy storage devices. Although this concept has already been adopted for the industrial production of LIB graphite anodes, the performance decay of cathode electrodes based on transition metal oxides processed in aqueous environments is still an open issue. In this study, we show that the addition of small quantities of phosphoric acid into the cathodic slurry yields Li[Ni0.33 Mn0.33 Co0.33 ]O2 electrodes that have an outstanding electrochemical performance in lithium-ion cells. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Thermally responsive polymer electrolytes for inherently safe electrochemical energy storage

NASA Astrophysics Data System (ADS)

Kelly, Jesse C.

Electrochemical double layer capacitors (EDLCs), supercapacitors and Li-ion batteries have emerged as premier candidates to meet the rising demands in energy storage; however, such systems are limited by thermal hazards, thermal runaway, fires and explosions, all of which become increasingly more dangerous in large-format devices. To prevent such scenarios, thermally-responsive polymer electrolytes (RPEs) that alter properties in electrochemical energy storage devices were designed and tested. These RPEs will be used to limit or halt device operation when temperatures increase beyond a predetermined threshold, therefore limiting further heating. The development of these responsive systems will offer an inherent safety mechanism in electrochemical energy storage devices, while preserving the performance, lifetimes, and versatility that large-format systems require. Initial work focused on the development of a model system that demonstrated the concept of RPEs in an electrochemical device. Aqueous electrolyte solutions of polymers exhibiting properties that change in response to temperature were developed for applications in EDLCs and supercapacitors. These "smart materials" provide a means to control electrochemical systems where polymer phase separation at high temperatures affects electrolyte properties and inhibits device performance. Aqueous RPEs were synthesized using N-isopropylacrylamide, which governs the thermal properties, and fractions of acrylic acid or vinyl sulfonic acids, which provide ions to the solution. The molecular properties of these aqueous RPEs, specifically the ionic composition, were shown to influence the temperature-dependent electrolyte properties and the extent to which these electrolytes control the energy storage characteristics of a supercapacitor device. Materials with high ionic content provided the highest room temperature conductivity and electrochemical activity; however, RPEs with low ionic content provided the highest "on-off" ratio in electrochemical activity at elevated temperatures. Overall, solution pH and conductivity were altered by an order of magnitude and device performance (ability to store charge) decreased by over 70%. After demonstration of a model responsive electrolyte in an aqueous system, ionic liquid (IL) based electrolytes were developed as a means of controlling the electrochemical performance in the non-aqueous environments that batteries, specifically Li-ion, require. Here, two systems were developed: (1) an electrolyte comprising poly(ethylene oxide) (PEO), the IL, [EMIM][BF4], and a lithium salt and (2) an electrolyte comprising poly(benzyl methacrylate) (PBzMA), the IL, [EMIM][TFSI], and a lithium salt. In each system, the polymer-IL phase separation inhibited device operation at elevated temperatures. For the PEO/IL electrolyte, the thermally induced liquid-liquid phase separation was shown to decrease the ionic conductivity, thereby affecting the concentration of ions at the electrode. Additionally, an increasing charge transfer resistance associated with the phase separated polymer coating the porous electrode was shown to limit electrochemical activity significantly. For the PBzMA/IL electrolyte, the solid-liquid phase separation did not show a change in conductivity, but did cause a drastic increase in charge transfer resistance, effectively shutting off Li-ion battery operation at high temperatures. Such responsive mixtures provide a transformative approach to regulating electrochemical processes, which is necessary to achieve inherently safe operation in large format energy storage with EDLCs, supercapacitors and Li-ion batteries.

Removal of hydrogen sulfide as ammonium sulfate from hydropyrolysis product vapors

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

Marker, Terry L.; Felix, Larry G.; Linck, Martin B.

A system and method for processing biomass into hydrocarbon fuels that includes processing a biomass in a hydropyrolysis reactor resulting in hydrocarbon fuels and a process vapor stream and cooling the process vapor stream to a condensation temperature resulting in an aqueous stream. The aqueous stream is sent to a catalytic reactor where it is oxidized to obtain a product stream containing ammonia and ammonium sulfate. A resulting cooled product vapor stream includes non-condensable process vapors comprising H.sub.2, CH.sub.4, CO, CO.sub.2, ammonia and hydrogen sulfide.

Removal of hydrogen sulfide as ammonium sulfate from hydropyrolysis product vapors

DOEpatents

Marker, Terry L; Felix, Larry G; Linck, Martin B; Roberts, Michael J

2014-10-14

A system and method for processing biomass into hydrocarbon fuels that includes processing a biomass in a hydropyrolysis reactor resulting in hydrocarbon fuels and a process vapor stream and cooling the process vapor stream to a condensation temperature resulting in an aqueous stream. The aqueous stream is sent to a catalytic reactor where it is oxidized to obtain a product stream containing ammonia and ammonium sulfate. A resulting cooled product vapor stream includes non-condensable process vapors comprising H.sub.2, CH.sub.4, CO, CO.sub.2, ammonia and hydrogen sulfide.

Anti-arthritic activity of aqueous-methanolic extract and various fractions of Berberis orthobotrys Bien ex Aitch.

PubMed

Alamgeer; Uttra, Ambreen Malik; Hasan, Umme Habiba

2017-07-18

The roots and stem bark of Berberis orthobotrys (Berberidaceae) have long been used traditionally to treat joint pain. Though, it has not been pharmacologically assessed for rheumatoid arthritis. The current study explores anti-arthritic activity and phytochemical analysis of aqueous-methanolic extract (30:70) and fractions (ethyl acetate, n-butanol, and aqueous) of Berberis orthobotrys roots. Anti-arthritic potential was evaluated in vitro using protein denaturation (bovine serum albumin and egg albumin) and membrane stabilization methods at 12.5-800 μg/ml concentration and in vivo via turpentine oil, formaldehyde and Complete Freund Adjuvant (CFA) models at 50, 100 and 150 mg/kg doses. Also, in vitro antioxidant ability was appraised by reducing power assay. Moreover, total flavonoid content, Fourier transform infrared spectroscopy and High performance liquid chromatography of n-butanol fraction were performed. The results revealed concentration dependent inhibition of albumin denaturation and notable RBC membrane stabilization, with maximum results obtained at 800 μg/ml. Similarly, plant exhibited dose dependent anti-arthritic effect in turpentine oil and formaldehyde models, with maximum activity observed at 150 mg/kg. The results of CFA model depicted better protection against arthritic lesions and body weight alterations. Also, B.orthobotrys remarkably ameliorated altered hematological parameters, rheumatoid factor and positively modified radiographic and histopathological changes. Additionally, plant exhibited remarkable anti-oxidant activity. Moreover, phytochemical analysis revealed polyphenols and flavonoids. Taken together, these results support traditional use of B.orthobotrys as potent anti-arthritic agent that may be proposed for rheumatoid arthritis treatment.

Method and apparatus for destroying organic contaminants in aqueous liquids

DOEpatents

Donaldson, T.L.; Wilson, J.H.

1993-09-21

A method and apparatus for destroying organic contaminants, such as trichloroethylene, in aqueous liquids, such as groundwater, utilizing steam stripping integrated with biodegradation. The contaminated aqueous liquid is fed into a steam stripper causing the volatilization of essentially all of the organic contaminants and a portion of the aqueous liquid. The majority of the aqueous liquid is discharged from the steam stripper. The volatilized vapors are then condensed to the liquid phase and introduced into a bioreactor. The bioreactor contains methanotrophic microorganisms which convert the organic contaminants into mainly carbon dioxide. The effluent from the bioreactor is then recycled back to the steam stripper for further processing. 2 figures.

Method and apparatus for destroying organic contaminants in aqueous liquids

DOEpatents

Donaldson, Terrence L.; Wilson, James H.

1993-01-01

A method and apparatus for destroying organic contaminants, such as trichloroethylene, in aqueous liquids, such as groundwater, utilizing steam stripping integrated with biodegradation. The contaminated aqueous liquid is fed into a steam stripper causing the volatilization of essentially all of the organic contaminants and a portion of the aqueous liquid. The majority of the aqueous liquid is discharged from the steam stripper. The volatilized vapors are then condensed to the liquid phase and introduced into a bioreactor. The bioreactor contains methanotrophic microorganisms which convert the organic contaminants into mainly carbon dioxide. The effluent from the bioreactor is then recycled back to the steam stripper for further processing.

Mesoscale fabrication and design

NASA Astrophysics Data System (ADS)

Hayes, Gregory R.

A strong link between mechanical engineering design and materials science and engineering fabrication can facilitate an effective and adaptable prototyping process. In this dissertation, new developments in the lost mold-rapid infiltration forming (LM-RIF) process is presented which demonstrates the relationship between these two fields of engineering in the context of two device applications. Within the LM-RIF process, changes in materials processing and mechanical design are updated iteratively, often aided by statistical design of experiments (DOE). The LM-RIF process was originally developed by Antolino and Hayes et al to fabricate mesoscale components. In this dissertation the focus is on advancements in the process and underlying science. The presented advancements to the LM-RIF process include an augmented lithography procedure, the incorporation of engineered aqueous and non-aqueous colloidal suspensions, an assessment of constrained drying forces during LM-RIF processing, mechanical property evaluation, and finally prototype testing and validation. Specifically, the molding procedure within the LM-RIF process is capable of producing molds with thickness upwards of 1mm, as well as multi-layering to create three dimensional structures. Increasing the mold thickness leads to an increase in the smallest feature resolvable; however, the increase in mold thickness and three dimensional capability has expanded the mechanical design space. Tetragonally stabilized zirconia (3Y-TZP) is an ideal material for mesoscale instruments, as it is biocompatible, exhibits high strength, and is chemically stable. In this work, aqueous colloidal suspensions were formulated with two new gel-binder systems, increasing final natural orifice translumenal endoscopic surgery (NOTES) instrument yield from 0% to upwards of 40% in the best case scenario. The effects of the gel-binder system on the rheological behavior of the suspension along with the thermal characteristics of the gel-binder system were characterized. Finally, mechanical properties of ceramic specimens were obtained via 3-point bend testing. Another candidate material for NOTES devices as well as cellular contact aided compliant mechanisms (C3M) devices is 300 series stainless steel (300 series stainless steel). 300 series stainless steel is a common biocompatible material; it is used in surgical applications, exhibits a high corrosion resistance, and has high strength to failure. New, high solids loading, non-aqueous colloidal suspensions of 300 series stainless steel were formulated and incorporated into the LM-RIF process. The rheological behavior and thermal characteristics of the non-aqueous colloidal suspensions were analyzed and engineered to operate within the LM-RIF process. Final part yield with the non-aqueous colloidal suspensions was higher than that of the aqueous ceramic suspensions. Mechanical properties of 300 series stainless steel specimens were determined via 3-point bend testing. Furthermore, new composite non-aqueous colloidal suspensions of 3Y-TZP and 300 series stainless steel were formulated and incorporated into the LM-RIF process. The composite materials showed an increase in final part yield, and an increase in yield strength compared to pure 300 series stainless steel was determined by Vickers hardness testing. The successful incorporation of composite suspensions in the LM-RIF process was facilitated through an analysis of the rheological behavior as a function of solids loading and ceramic to metal ratio. Optimized designs of NOTES instruments, as well as C3M devices were manufactured using the LM-RIF process with the non-aqueous 300 series stainless steel suspension. The performance of the prototype NOTES instruments was evaluated and compared against the theoretically predicted performance results, showing good agreement. Similarly, good agreement was seen between the stress-displacement behavior of prototype C3M devices when compared to the theoretically calculated stress-displacement results. Finally, in a comparison by endoscopic surgeons at Hershey Medical Center between an existing industry standard endoscopic device and the mesoscale instrument prototypes fabricated via the LM-RIF process, the prototype design performed favorably in almost all categories. (Abstract shortened by UMI.)

Process for recovering hydrocarbons from a diatomite-type ore

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

Davis, B.W.

1983-02-15

A process for recovering hydrocarbons from a diatomite-type ore which comprises contacting the diatomite ore with a C/sub 4/-C/sub 10/ alcohol and thereafter contacting the diatomite ore-alcohol mixture with an aqueous alkaline solution to separate a hydrocarbon-alcohol phase and an alkaline aqueous phase containing the stripped diatomite ore. Thereafter, the alcohol is distilled off from the hydrocarbon phase and recycled back into the initial process.

PROCESS OF SEPARATING PLUTONIUM VALUES BY ELECTRODEPOSITION

DOEpatents

Whal, A.C.

1958-04-15

A process is described of separating plutonium values from an aqueous solution by electrodeposition. The process consists of subjecting an aqueous 0.1 to 1.0 N nitric acid solution containing plutonium ions to electrolysis between inert metallic electrodes. A current density of one milliampere io one ampere per square centimeter of cathode surface and a temperature between 10 and 60 d C are maintained. Plutonium is electrodeposited on the cathode surface and recovered.

Martian fluvial conglomerates at Gale crater.

PubMed

Williams, R M E; Grotzinger, J P; Dietrich, W E; Gupta, S; Sumner, D Y; Wiens, R C; Mangold, N; Malin, M C; Edgett, K S; Maurice, S; Forni, O; Gasnault, O; Ollila, A; Newsom, H E; Dromart, G; Palucis, M C; Yingst, R A; Anderson, R B; Herkenhoff, K E; Le Mouélic, S; Goetz, W; Madsen, M B; Koefoed, A; Jensen, J K; Bridges, J C; Schwenzer, S P; Lewis, K W; Stack, K M; Rubin, D; Kah, L C; Bell, J F; Farmer, J D; Sullivan, R; Van Beek, T; Blaney, D L; Pariser, O; Deen, R G

2013-05-31

Observations by the Mars Science Laboratory Mast Camera (Mastcam) in Gale crater reveal isolated outcrops of cemented pebbles (2 to 40 millimeters in diameter) and sand grains with textures typical of fluvial sedimentary conglomerates. Rounded pebbles in the conglomerates indicate substantial fluvial abrasion. ChemCam emission spectra at one outcrop show a predominantly feldspathic composition, consistent with minimal aqueous alteration of sediments. Sediment was mobilized in ancient water flows that likely exceeded the threshold conditions (depth 0.03 to 0.9 meter, average velocity 0.20 to 0.75 meter per second) required to transport the pebbles. Climate conditions at the time sediment was transported must have differed substantially from the cold, hyper-arid modern environment to permit aqueous flows across several kilometers.

Imino Acids in the Murchison Meteorite: Evidence of Strecker Reactions

NASA Technical Reports Server (NTRS)

Lerner, N. R.; Cooper, G. W.

2003-01-01

Both alpha-amino acids and alpha-hydroxy acids occur in aqueous extracts of the Murchison carbonaceous meteorite. The Strecker-cyanohydrin reaction, the reaction of carbonyl compounds, cyanide, and ammonia to produce amino and hydroxy acids, has been proposed as a source of such organic acids in meteorites. Such syntheses are consistent with the suggestion that interstellar precursors of meteoritic organic compounds accreted on the meteorite parent body together with other ices. Subsequent internal heating of the parent body melted these ices and led to the formation of larger compounds in synthetic reactions during aqueous alteration, which probably occurred at temperatures between 273K and 298K. In the laboratory, imino acids are observed as important by-products of the Strecker synthesis.

Martian fluvial conglomerates at Gale Crater

USGS Publications Warehouse

Williams, Rebecca M.E.; Grotzinger, J.P.; Dietrich, W.E.; Gupta, S.; Sumner, D.Y.; Wiens, R.C.; Mangold, N.; Malin, M.C.; Edgett, K.S.; Maurice, S.; Forni, O.; Gasnault, O.; Ollila, A.; Newsom, Horton E.; Dromart, G.; Palucis, M.C.; Yingst, R.A.; Anderson, Ryan B.; Herkenhoff, K. E.; Le Mouélic, S.; Goetz, W.; Madsen, M.B.; Koefoed, A.; Jensen, J.K.; Bridges, J.C.; Schwenzer, S.P.; Lewis, K.W.; Stack, K.M.; Rubin, D.; Kah, L.C.; Bell, J.F.; Farmer, J.D.; Sullivan, R.; Van Beek, T.; Blaney, D.L.; Pariser, O.; Deen, R.G.

2013-01-01

Observations by the Mars Science Laboratory Mast Camera (Mastcam) in Gale crater reveal isolated outcrops of cemented pebbles (2 to 40 millimeters in diameter) and sand grains with textures typical of fluvial sedimentary conglomerates. Rounded pebbles in the conglomerates indicate substantial fluvial abrasion. ChemCam emission spectra at one outcrop show a predominantly feldspathic composition, consistent with minimal aqueous alteration of sediments. Sediment was mobilized in ancient water flows that likely exceeded the threshold conditions (depth 0.03 to 0.9 meter, average velocity 0.20 to 0.75 meter per second) required to transport the pebbles. Climate conditions at the time sediment was transported must have differed substantially from the cold, hyper-arid modern environment to permit aqueous flows across several kilometers.

Ultrafast fluorescence quenching dynamics of Atto655 in the presence of N-acetyltyrosine and N-acetyltryptophan in aqueous solution: proton-coupled electron transfer versus electron transfer.

PubMed

Zhang, Ying; Yuan, Shuwei; Lu, Rong; Yu, Anchi

2013-06-20

We studied the ultrafast fluorescence quenching dynamics of Atto655 in the presence of N-acetyltyrosine (AcTyr) and N-acetyltryptophan (AcTrp) in aqueous solution with femtosecond transient absorption spectroscopy. We found that the charge-transfer rate between Atto655 and AcTyr is about 240 times smaller than that between Atto655 and AcTrp. The pH value and D2O dependences of the excited-state decay kinetics of Atto655 in the presence of AcTyr and AcTrp reveal that the quenching of Atto655 fluorescence by AcTyr in aqueous solution is via a proton-coupled electron-transfer (PCET) process and that the quenching of Atto655 fluorescence by AcTrp in aqueous solution is via an electron-transfer process. With the version of the semiclassical Marcus ET theory, we derived that the electronic coupling constant for the PCET reaction between Atto655 and AcTyr in aqueous solution is 8.3 cm(-1), indicating that the PCET reaction between Atto655 and AcTyr in aqueous solution is nonadiabatic.

Differential capacitance probe for process control involving aqueous dielectric fluids

DOEpatents

Svoboda, John M.; Morrison, John L.

2002-10-08

A differential capacitance probe device for process control involving aqueous dielectric fluids is disclosed. The device contains a pair of matched capacitor probes configured in parallel, one immersed in a sealed container of reference fluid, and the other immersed in the process fluid. The sealed container holding the reference fluid is also immersed in the process fluid, hence both probes are operated at the same temperature. Signal conditioning measures the difference in capacitance between the reference probe and the process probe. The resulting signal is a control error signal that can be used to control the process.

Morphological alterations in the synganglion and integument of Rhipicephalus sanguineus ticks exposed to aqueous extracts of neem leaves (Azadirachta indica A. JUSS).

PubMed

Remedio, R N; Nunes, P H; Anholeto, L A; Camargo-Mathias, M I

2014-12-01

Currently, the necessity of controlling infestation by ticks, especially by Rhipicephalus sanguineus, has led researchers and public health managers around the world to search for new and more efficient control methods. This way, we can highlight neem (Azadirachta indica A. Juss) leaf, bark, and seed extracts, which have been very effective on tick control, and moreover causing less damage to the environment and to the host. This study showed the potential of neem as a control method for R. sanguineus through morphological and morphometric evaluation of the integument and synganglion of females, in semiengorged stage. To attain this, routine techniques of optical microscopy, scanning electron microscopy and morphometry of the cuticle and subcuticle of the integument were applied. Expressive morphological alterations were observed in both organs, presenting a dose-dependent effect. Integument epithelial cells and nerve cells of the synganglion showed signs of cell vacuolation, dilated intercellular boundaries, and cellular disorganization, alterations not previously reported in studies with neem. In addition, variations in subcuticle thickness were also observed. In general, the effects of neem are multiple, and affect the morphology and physiology of target animals in various ways. The results presented in this work are the first evidence of its effects in the coating and nervous system of ticks, thus allowing an indication of neem aqueous extracts as a potential control method of the brown dog tick and opening new perspectives on acaricide use. © 2014 Wiley Periodicals, Inc.

CM and CO chondrites: A common parent body or asteroidal neighbors? Insights from chondrule silicates

NASA Astrophysics Data System (ADS)

Schrader, Devin L.; Davidson, Jemma

2017-10-01

By investigating the petrology and chemical composition of type II (FeO-rich) chondrules in the Mighei-like carbonaceous (CM) chondrites we constrain their thermal histories and relationship to the Ornans-like carbonaceous (CO) chondrites. We identified FeO-rich relict grains in type II chondrules by their Fe/Mn ratios; their presence indicates chondrule recycling among type II chondrules. The majority of relict grains in type II chondrules are FeO-poor olivine grains. Consistent with previous studies, chemical similarities between CM and CO chondrite chondrules indicate that they had similar formation conditions and that their parent bodies probably formed in a common region within the protoplanetary disk. However, important differences such as mean chondrule size and the lower abundance of FeO-poor relicts in CM chondrite type II chondrules than in CO chondrites suggest CM and CO chondrules did not form together and they likely originate from distinct parent asteroids. Despite being aqueously altered, many CM chondrites contain pre-accretionary anhydrous minerals (i.e., olivine) that are among the least thermally metamorphosed materials in chondrites according to the Cr2O3 content of their ferroan olivine. The presence of these minimally altered pre-accretionary chondrule silicates suggests that samples to be returned from aqueously altered asteroids by the Hayabusa2 and OSIRIS-REx asteroid sample return missions, even highly hydrated, may contain silicates that can provide information about the pre-accretionary histories and conditions of asteroids Ryugu and Bennu, respectively.

Ice growth from supercooled aqueous solutions of benzene, naphthalene, and phenanthrene.

PubMed

Liyana-Arachchi, Thilanga P; Valsaraj, Kalliat T; Hung, Francisco R

2012-08-23

Classical molecular dynamics (MD) were performed to investigate the growth of ice from supercooled aqueous solutions of benzene, naphthalene, or phenanthrene. The main objective of this study is to explore the fate of those aromatic molecules after freezing of the supercooled aqueous solutions, i.e., if these molecules become trapped inside the ice lattice or if they are displaced to the QLL or to the interface with air. Ice growth from supercooled aqueous solutions of benzene, naphthalene, or phenanthrene result in the formation of quasi-liquid layers (QLLs) at the air/ice interface that are thicker than those observed when pure supercooled water freezes. Naphthalene and phenanthrene molecules in the supercooled aqueous solutions are displaced to the air/ice interface during the freezing process at both 270 and 260 K; no incorporation of these aromatics into the ice lattice is observed throughout the freezing process. Similar trends were observed during freezing of supercooled aqueous solutions of benzene at 270 K. In contrast, a fraction of the benzene molecules become trapped inside the ice lattice during the freezing process at 260 K, with the rest of the benzene molecules being displaced to the air/ice interface. These results suggest that the size of the aromatic molecule in the supercooled aqueous solution is an important parameter in determining whether these molecules become trapped inside the ice crystals. Finally, we also report potential of mean force (PMF) calculations aimed at studying the adsorption of gas-phase benzene and phenanthrene on atmospheric air/ice interfaces. Our PMF calculations indicate the presence of deep free energy minima for both benzene and phenanthrene at the air/ice interface, with these molecules adopting a flat orientation at the air/ice interface.

Identical Origin for Halide and Sulfate Efflorescences on Meteorite Finds and Sulfate Veins in Orgueil

NASA Technical Reports Server (NTRS)

Zolensky, M. E.

2000-01-01

Halide and sulfate efflorescences are common on meteorite finds, especially those from cold deserts. Meanwhile, the late-stage sulfate veins in Orgueil are universally accepted as having originated by the action of late-stage high fO2 aqueous alteration on an asteroid. I suggest here that these phenomena have essentially the same origin.