Science.gov

Sample records for organic-rich polymetallic concentrate

  1. Controls on porphyrin concentrations of Pennsylvanian organic-rich shales, Western U.S.A.

    USGS Publications Warehouse

    Clayton, J.L.; Michael, G.E.

    1990-01-01

    Organic-rich black shales of Middle Pennsylvanian (Desmoinesian) age occur over much of the central U.S. and as far west as the northern Denver and southeastern Powder River basins. Total organic carbon contents (Corg) are commonly greater than 10 wt %. Porphyrin concentrations (vanadyl + nickel) are as high as 40000 ppm relative to extractable bitumen. In bulk, the organic matter contained in the shales is mostly type II and III (Rock-Eval hydrogen indexes 200-400 mg of hydrocarbons/g of Corg). The finding of high porphyrin concentrations in type III organic matter is unusual but can be explained by a depositional model wherein high preservation of primary organic production (water column photosynthesis) is combined with substantial input of allochthonous organic matter. The allochthonous organic matter (low porphyrin concentration) may come from erosion during advance of the sea across the area or from fluvial transport from shore.

  2. Roasting of a sulfide polymetallic concentrate in a fluidized bed furnace

    NASA Astrophysics Data System (ADS)

    Savinova, Yu. A.; Popov, V. A.; Portov, A. B.; Tsemekhman, L. Sh.

    2014-05-01

    Three series of experiments on oxidizing roasting of sulfide polymetallic concentrates in a laboratory fluidized bed furnace are performed to develop an economically efficient technology of processing the sulfide polymetallic ore concentrate of the Artem'evsk deposit (Kazakhstan). The composition of the initial concentrate and the products of its oxidizing roasting are studied. The mineral composition of the concentrate is determined, and it demonstrates that this material tends toward intense spinel formation under oxidizing roasting conditions. The main structural constituents of the cinder are found to be sulfate-spinel conglomerates and oxide and sulfide particles. The possible ways of formation of these constituents are discussed using the obtained experimental data, the existing theoretical concepts, and the results of thermodynamic analysis. The calculations are performed using the FactSage software package and database. The formation of oxide and spinel components are found to be caused by both direct oxidation of sulfide minerals (primary processes) and the interaction of primary products with sulfuric anhydride and each other (secondary processes). In turn, all sulfates in the cinder are the products of secondary processes, and primary sulfate formation does not take place in roasting under the chosen conditions. Spinels cannot be completely removed from the cinder using their sulfation because of predominant consumption of sulfuric anhydride for interaction with oxide components. The optimum roasting conditions that ensure the formation of the best cinder for subsequent hydrometallurgical processing are chosen on the basis of the obtained data. The degree of extraction of nonferrous metals achieved upon leaching of the cinder is 94-96 wt %.

  3. "Isolation, identification, characterization and polymetallic concentrate leaching studies of tryptic soy- and peptone-resistant thermotolerant Acidithiobacillus ferrooxidans SRDSM2".

    PubMed

    Patel, Mitesh J; Tipre, Devayani R; Dave, Shailesh R

    2011-01-01

    Acidithiobacillus ferrooxidans strain SRDSM2 was isolated from silica containing soil sample collected at a Rajpardi lignite mine. The strain responded to the addition of 0.5 g/L peptone and 1.0 g/L tryptone soya broth in the ferrous sulphate tryptone soya broth (ITSB) medium with 35.3% and 29.6% increase in iron oxidation rate (IOR), but decrease in the IOR at higher peptone or tryptone soya broth levels. The presence of 4 mM of zinc as zinc sulphate in the medium increased the IOR by 24.4%. Forty percent of the inoculated cells survived even after exposure at 80 °C for 120 min and showed 30% ferrous iron oxidation. The Vmax and Ks for iron oxidation by the isolate were 344.82 mg/L/h and 32.25 g/L respectively. The isolate was able to oxidized ferrous iron even in presence of 4.06 M ionic strength of medium and leached>85% copper and zinc from the polymetallic concentrate. Thus, this isolate can be used for bioextraction of metals from polymetallic concentrate.

  4. DNA alterations triggered by environmentally relevant polymetallic concentrations in marine clams Ruditapes philippinarum and polychaete worms Hediste diversicolor.

    PubMed

    Dedeh, Amina; Ciutat, Aurélie; Tran, Damien; Bourdineaud, Jean-Paul

    2014-11-01

    We exposed marine clams (Ruditapes philippinarum) and aquatic worms (Hediste diversicolor) to environmentally relevant concentrations of two metal mixtures each containing three divalent metals [(C₁ in µg/L) cadmium (Cd) 1, mercury (Hg) 0.1, and lead (Pb) 4] and [C₂ in µg/L) Cd 17, Hg 1.1, and Pb 55]. Animals collected in the Arcachon Bay were exposed for 8 days in microcosms made up of a mixed biotope consisting of a water column and natural marine sediment both taken up from the Arcachon Bay. Bioaccumulation analysis showed a significant increase of Cd, Hg, and Pb in clams, particularly at C₂ concentration in the water column reaching, in soft body, 2.3 ± 0.3 µg Cd/g, 0.7 ± 0.2 µg Hg/g, and 45 µg Pb/g dry weight (dw). DNA alterations and upregulation of the cox1 mitochondrial gene were also observed in clam gill after exposure to the metal blend. For worms exposed to the C₂ metal blend, DNA alterations and significant increase of Cd and Hg concentrations were observed reaching 0.5 ± 0.1 µg Cd/g and 2 ± 0.6 µg Hg/g dw.

  5. Microporoelastic Modeling of Organic-Rich Shales

    NASA Astrophysics Data System (ADS)

    Khosh Sokhan Monfared, S.; Abedi, S.; Ulm, F. J.

    2014-12-01

    Organic-rich shale is an extremely complex, naturally occurring geo-composite. The heterogeneous nature of organic-rich shale and its anisotropic behavior pose grand challenges for characterization, modeling and engineering design The intricacy of organic-rich shale, in the context of its mechanical and poromechanical properties, originates in the presence of organic/inorganic constituents and their interfaces as well as the occurrence of porosity and elastic anisotropy, at multiple length scales. To capture the contributing mechanisms, of 1st order, responsible for organic-rich shale complex behavior, we introduce an original approach for micromechanical modeling of organic-rich shales which accounts for the effect of maturity of organics on the overall elasticity through morphology considerations. This morphology contribution is captured by means of an effective media theory that bridges the gap between immature and mature systems through the choice of system's microtexture; namely a matrix-inclusion morphology (Mori-Tanaka) for immature systems and a polycrystal/granular morphology for mature systems. Also, we show that interfaces play a role on the effective elasticity of mature, organic-rich shales. The models are calibrated by means of ultrasonic pulse velocity measurements of elastic properties and validated by means of nanoindentation results. Sensitivity analyses using Spearman's Partial Rank Correlation Coefficient shows the importance of porosity and Total Organic Carbon (TOC) as key input parameters for accurate model predictions. These modeling developments pave the way to reach a "unique" set of clay properties and highlight the importance of depositional environment, burial and diagenetic processes on overall mechanical and poromechanical behavior of organic-rich shale. These developments also emphasize the importance of understanding and modeling clay elasticity and organic maturity on the overall rock behavior which is of critical importance for a

  6. Nano-Chemomechanical Assessment of Organic Rich Shales

    NASA Astrophysics Data System (ADS)

    Abedi, S.; Slim, M. I.; Ferralis, N.; Ulm, F.

    2013-12-01

    Organic rich shales, a rapidly increasing source of fossil fuels, have recently gained significant attention from the geomechanics and geochemistry communities. Despite their importance, the chemomechanical characterization of organic rich shales remains a pressing challenge due to their highly heterogeneous microstructure, complex chemistry, and multiscale mechanical performances. Such complexity requires advanced and innovative characterization tools for a complete understanding of the role played by different constituents in the chemomechnaical properties at multiple scales. In this study, experimental and theoretical microporomechanics have been employed for assessing the microtexture and material invariant properties of clay-dominated organic rich shales at nanometer length scales. A novel experimental methodology consisting of instrumented nanoindenation experiments and Energy Dispersive X-ray Spectroscopy (EDX) is developed for the proper chemomechanical characterization of the main constituents of the composite shale material. Combining experimental characterization with micromechanical modeling, the material invariant properties and mesotexture of material main constituents are investigated. The results provide evidence that mature clay-dominated organic rich shale systems exhibit a kerogen stiffening of the mechanical properties of the elementary particles. Such a stiffening effect cannot be explained by classical micromechanics models based on mean-field theories and volume averaging where a property softening would be predicted. Furthermore, it is seen that the presence and chemical composition of organic matter affects mechanical properties of organic rich shales significantly. The role of kerogen maturity, type, and chemical composition on mechanical performance of the material is investigated by incorporating results from Raman Spectroscopy into the analysis. The results of this investigation are used to define a model of the fundamental building

  7. Organic-rich shales of the world land areas

    SciTech Connect

    Miller, J.B.

    1980-12-01

    Organic-rich shale is a fine-grained sedimentary rock containing up to 65% organic matter commonly referred to as ''kerogen.'' When subjected to heat, the rock is capable of yielding synthetic oil and/or combustible gas. The rock commonly called ''oil shale'' is one type of organic-rich shale even though it may be an impure limestone lithologically. Other types include black, carbonaceous, bituminous and cannel shales. All have one common characteristic which is important to us all; namely, they are a significant potential source of energy for our future needs. Oil shale and other organic-rich shale deposits throughout the world range in age from Cambrian to Tertiary (40-600 million years old). The major deposits were formed in large marine basins or embayments and in large lake basins with the deposits extending over thousands of square miles. Many lesser deposits formed in smaller bodies of water and in coastal swamps associated with coal beds. Based on a world-wide inventory compiled by the USGS in 1965, organic-rich shale deposits underlie about 20 million square miles of six continents: Africa, Asia, Australia-New Zealand, Europe, North America and South America. In shales grading 10+ G/T oil, the total in-place resource of these deposits is about 342 trillion barrels of shale oil with 712 billion barrels estimated recoverable.

  8. Improved automation of dissolved organic carbon sampling for organic-rich surface waters.

    PubMed

    Grayson, Richard P; Holden, Joseph

    2016-02-01

    In-situ UV-Vis spectrophotometers offer the potential for improved estimates of dissolved organic carbon (DOC) fluxes for organic-rich systems such as peatlands because they are able to sample and log DOC proxies automatically through time at low cost. In turn, this could enable improved total carbon budget estimates for peatlands. The ability of such instruments to accurately measure DOC depends on a number of factors, not least of which is how absorbance measurements relate to DOC and the environmental conditions. Here we test the ability of a S::can Spectro::lyser™ for measuring DOC in peatland streams with routinely high DOC concentrations. Through analysis of the spectral response data collected by the instrument we have been able to accurately measure DOC up to 66 mg L(-1), which is more than double the original upper calibration limit for this particular instrument. A linear regression modelling approach resulted in an accuracy >95%. The greatest accuracy was achieved when absorbance values for several different wavelengths were used at the same time in the model. However, an accuracy >90% was achieved using absorbance values for a single wavelength to predict DOC concentration. Our calculations indicated that, for organic-rich systems, in-situ measurement with a scanning spectrophotometer can improve fluvial DOC flux estimates by 6 to 8% compared with traditional sampling methods. Thus, our techniques pave the way for improved long-term carbon budget calculations from organic-rich systems such as peatlands.

  9. A depositional model for organic-rich Duvernay Formation mudstones

    NASA Astrophysics Data System (ADS)

    Knapp, Levi J.; McMillan, Julia M.; Harris, Nicholas B.

    2017-01-01

    The Upper Devonian Duvernay Formation of western Canada is an organic-rich shale formation now targeted as a hydrocarbon reservoir. We present a detailed sedimentological analysis of the Duvernay Formation in order to better understand organic-rich mudstone depositional processes and conditions and to characterize the vertical and lateral heterogeneity of mudstone lithofacies that affect petrophysical and geomechanical rock properties. Organic-rich mudstone facies of the Duvernay Formation were deposited in a dynamic depositional environment by a variety of sediment transport mechanisms, including suspension settling, turbidity currents, and bottom water currents in variably oxygenated bottom waters. Suspension settling dominated in distal relatively deep areas of the basin, but evidence for weak turbidity currents and bottom water currents was observed in the form of graded beds and thin grain-supported siltstone laminae. Organic enrichment primarily occurred in distal areas as a result of bottom water anoxia and low depositional rates of inorganic sediment. In deep water locations near platform margins, alternating silty-sandy contourite beds and organic-rich mudstone beds are present, the former interpreted to have been deposited and reworked by bottom water currents flowing parallel to slope. In shallower, more oxygenated settings, mudstone lithologies vary from calcareous to argillaceous. These sediments were deposited from suspension settling, turbidity currents, and bottom water currents, although primary sedimentary structures are often obscured by extensive bioturbation. Locally, organic enrichment in dysoxic rather than anoxic bottom waters was driven by a slightly increased sedimentation rate and possibly also by aggregation of sedimentary particles in the water column due to interaction between organic matter and clay minerals. Large variations observed in sediment composition, from siliceous to calcareous to argillaceous, reflect multiple biogenic

  10. Storage and Transport of Hydrocarbons in Organic-Rich Mudstones

    NASA Astrophysics Data System (ADS)

    Kleinberg, R. L.; Falk, K. I.; Coasne, B. A.

    2014-12-01

    Organic-rich mudstones - also called source rocks - are capable of economically producing significant quantities of oil and natural gas. Although the static physical and chemical properties of these rocks are generally well understood, the dynamics of hydrocarbon fluids in them is still a matter of conjecture and debate. In conventional porous petroleum reservoirs, the solid matrix is composed of inorganic minerals such as quartz or calcite, pore sizes are in the range of micrometers, and the following assumptions generally hold to a high degree of approximation: (1) thermodynamic and transport properties of the pore fluids are identical to their bulk values; (2) matrix solids are inert; (3) fluid-solid interactions are fully described by simple notions of wettability. In contrast, in source rock, oil and gas are in intimate contact with an organic solid called kerogen, the pore spaces of which are comparable to molecular dimensions. Therefore the dynamics of hydrocarbons in organic-rich mudstones must take into account significant departures from bulk thermodynamics and hydrodynamics, and fluid-solid interactions are molecular-species specific. We present a multi-scale model of organic-rich mudstone that is consistent with a variety of molecular-level computations and physical property measurements, and that may serve as a basis for understanding the oil and gas production mechanisms of these rocks.

  11. Paleohydrologic controls on methanogenesis in organic-rich saline aquifers

    NASA Astrophysics Data System (ADS)

    McIntosh, J.; Petsch, S.; Schlegel, M.; Osborn, S.

    2007-12-01

    Freshwater recharge into the margins of sedimentary basins, during periods of continental glaciation, stimulated microbial methane generation in organic-rich shales and coal beds, by significantly diluting the ambient formation water salinity. Subglacial recharge may have also transported microorganisms and nutrients into the subsurface environment. Methane is generated by a diverse consortium of both acetoclastic and CO2-reducing methanogenic Archaea, and adsorbed onto the organic matter. These shallow methane accumulations account for ~20% of the total U.S. natural gas production. Anaerobic microbial metabolism of shales and coals is in part controlled by the volume of pore waters and fluid composition, amount of extractable organic matter and intermediary substrates, reservoir temperature, and mass transport processes that provide essential rock-derived nutrients and organic acids. Methanogens are most active in low salinity environments (<2.5 mol/L Cl) with no SO4, and at the interfaces between confining units and adjacent aquifers where diffusion dominates. Microbial degradation of organic matter generates high alkalinity concentrations, which may induce calcite precipitation in shale fractures and coal cleats, which can in turn modify the subsurface hydrology. Microbial methanogenesis also imparts a strong control on the cycling of carbon, H2, and other elements in the subsurface environment. This presentation will focus on the timing of recharge and establishment of microbial communities within the Upper Devonian black shales, Pennsylvanian coal beds, and overlying glacial drift in the Illinois Basin, and the importance of continued groundwater flow on active methane generation and accumulation. There is an approximately 65-70 per mil depletion in 13C of CH4, relative to the precursor CO2 in the Upper Devonian shales, Pennsylvanian coals, and glacial drift. In addition, there is a linear correlation between the dD values of co- produced formation waters and

  12. Testing Organic-Rich Sediments as Recorders of the Seawater Os Isotope Record

    NASA Astrophysics Data System (ADS)

    Paquay, F.; Ravizza, G.

    2006-12-01

    Organic-rich sediments of Eocene to Oligocene age, deposited under anoxic to moderately reducing conditions from the Ocean Drilling Program (ODP) Site 959 on the continental margin of the Cote d'Ivoire- Ghana were investigated in order to empirically test the fidelity of organic-rich marine sediments as recorders of past seawater Os isotope variations. Although initial ^{187}Os/^{188}Os ratios derived from Re-Os isochrons provide the best available constraints on the Mesozoic and Paleozoic portions of the marine Os isotope record, no systematic study comparing Re-Os analyses of organic-rich marine sediments to a well established portion of the Cenozoic marine Os isotope record has been made. Forty-two bulk sediment Os analyses from Site 959 reveal that Os concentrations range from 80 to 550 pg/g, indicating the dominance of hydrogenous Os. Measured ^{187}Os/^{188}Os ratios range from 0.48 to 1.40 and are larger than the ^{187}Os/^{188}Os of contemporaneous seawater. Variability among replicate analyses clearly indicates significant powder heterogeneity in some samples. A small subset of these samples has been subjected to an oxidative partial dissolution that allows analyses of Re and Os on the same sample splits, and calculation of initial ^{187}Os/^{188}Os ratios using an age model constrained by biostratigraphy. Comparison of leach analyses to bulk sediment analyses indicates that all the Re and in excess of 90% of the Os is liberated during leaching. In most cases the ^{187}Os/^{188}Os of leachable Os is indistinguishable from that of the bulk sediment. The resulting calculated initial ^{187}Os/^{188}Os ratios are in general agreement with the independently established Os isotope record of the Eocene-Oligocene transition. In particular, one sample analyzed records the pronounced minimum in the seawater ^{187}Os/^{188}Os record during the late Eocene. In total these results indicate that the Re-Os systematics of Cenozoic organic-rich sediments effectively record

  13. Molecular Analyzer for Complex Refractory Organic-Rich Surfaces (MACROS)

    NASA Technical Reports Server (NTRS)

    Getty, Stephanie A.; Cook, Jamie E.; Balvin, Manuel; Brinckerhoff, William B.; Li, Xiang; Grubisic, Andrej; Cornish, Timothy; Ferrance, Jerome; Southard, Adrian

    2017-01-01

    The Molecular Analyzer for Complex Refractory Organic-rich Surfaces, MACROS, is a novel instrument package being developed at NASA Goddard Space Flight Center. MACROS enables the in situ characterization of a sample's composition by coupling two powerful techniques into one compact instrument package: (1) laser desorption/ionization time-of-flight mass spectrometry (LDMS) for broad detection of inorganic mineral composition and non-volatile organics, and (2) liquid-phase extraction methods to gently isolate the soluble organic and inorganic fraction of a planetary powder for enrichment and detailed analysis by liquid chromatographic separation coupled to LDMS. The LDMS is capable of positive and negative ion detection, precision mass selection, and fragment analysis. Two modes are included for LDMS: single laser LDMS as the broad survey mode and two step laser mass spectrometry (L2MS). The liquid-phase extraction will be done in a newly designed extraction module (EM) prototype, providing selectivity in the analysis of a complex sample. For the sample collection, a diamond drill front end will be used to collect rock/icy powder. With all these components and capabilities together, MACROS offers a versatile analytical instrument for a mission targeting an icy moon, carbonaceous asteroid, or comet, to fully characterize the surface composition and advance our understanding of the chemical inventory present on that body.

  14. Polymetallic complexes in microemulsions for the hydrolysis of 4-nitrophenyl phosphate: a bio-mimetic model for decontamination of organophosphates in the environment.

    PubMed

    Tafesse, Fikru; Deppa, Ntsapokazi C

    2004-06-01

    Reactions of several metal ions and polymetallic complexes toward hydrolysis of 4-nitrophenyl phosphate (NPP) were investigated at 10(-3)M concentration in oil-in-water microemulsions and aqueous media. The reactions were monitored by measuring the absorbance of the nitrophenolate ion produced in the reaction aliquots with time. The order of effectiveness of the metal ions and polymetallic complexes at neutral pH toward hydrolysis of NPP was found to be Turnbull's Blue>magnetite>Fe(III)>Fe(II)>Co(II)>Ca(II)>Cu(II). The possible application of these systems for sites contaminated with chemical warfare agents such as organophosphates is discussed.

  15. Microbial control of silicate weathering in organic-rich ground water

    USGS Publications Warehouse

    Hiebert, Franz K.; Bennett, Philip C.

    1992-01-01

    An in situ microcosm study of the influence of surface-adhering bacteria on silicate diagenesis in a shallow petroleum-contaminated aquifer showed that minerals were colonized by indigenous bacteria and chemically weathered at a rate faster than theoretically predicted. Feldspar and quartz fragments were placed in anoxic, organic-rich ground water, left for 14 months, recovered, and compared to unreacted controls with scanning electron microscopy. Ground-water geochemistry was characterized before and after the experiment. Localized mineral etching probably occurred in a reaction zone at the bacteria-mineral interface where high concentrations of organic acids, formed by bacteria during metabolism of hydrocarbon, selectively mobilized silica and aluminum from the mineral surface.

  16. Archaea in Organic-Lean and Organic-Rich Marine Subsurface Sediments: An Environmental Gradient Reflected in Distinct Phylogenetic Lineages

    PubMed Central

    Durbin, Alan M.; Teske, Andreas

    2012-01-01

    Examining the patterns of archaeal diversity in little-explored organic-lean marine subsurface sediments presents an opportunity to study the association of phylogenetic affiliation and habitat preference in uncultured marine Archaea. Here we have compiled and re-analyzed published archaeal 16S rRNA clone library datasets across a spectrum of sediment trophic states characterized by a wide range of terminal electron-accepting processes. Our results show that organic-lean marine sediments in deep marine basins and oligotrophic open ocean locations are inhabited by distinct lineages of archaea that are not found in the more frequently studied, organic-rich continental margin sediments. We hypothesize that different combinations of electron donor and acceptor concentrations along the organic-rich/organic-lean spectrum result in distinct archaeal communities, and propose an integrated classification of habitat characteristics and archaeal community structure. PMID:22666218

  17. Uranium and radium diffusion in organic-rich sediments (sapropels)

    NASA Astrophysics Data System (ADS)

    Gourgiotis, A.; Reyss, J.-L.; Frank, N.; Guihou, A.; Anagnostou, C.

    2011-09-01

    Among the late Quaternary Mediterranean sapropels, the S5 (125 ka) is one of the best preserved due to its high organic carbon content that has limited postdepositional oxidation. The high uranium content in this sapropel, >40 dpm g-1, makes this layer interesting for studying uranium series disequilibrium in organic-rich sediments. For this reason, the present work provides isotopic measurements of the U decay series in a S5 sapropel by applying more precise mass spectrometric methods, TIMS/MC-ICPMS, and gamma spectrometry. Assuming that U in the sapropel mostly originated from seawater the (234U/238U), (230Th/238U), (226Ra/230Th) and (231Pa/235U) activity ratios show systematic deviations from the theoretical values for a closed-system evolution of the U series over the 125 ka since sapropel formation. The radiogenic 234Urad and 226Ra show clear evidence of migration in the sapropel with modeled diffusion coefficients of (7.1 ± 1.1) × 10-12 cm2 s-1 and (1.6 ± 0.2) × 10-10 cm2 s-1, respectively. The diffusion of 234Urad cannot explain the high (230Th/238U) and (231Pa/235U) activity ratios observed in the sapropel. Two possible mechanisms or a combination of both are proposed for explaining the irregular (230Th/238U) and (231Pa/235U) activity profiles in sapropel S5. The first one is an enhanced export flux of 230Thxs and 231Paxs excesses exceeding the production rate in seawater, during the time of sapropel formation, and the second one is diffusion of authigenic Uauth in the sapropel. However, the ambiguous determination of 230Thxs and 231Paxs in the sapropel and the poorly understood processes that might lead to Uauth migration in anoxic sediments still limit a final explanation for the deviation of (230Th/238U) and (231Pa/235U) activity ratios from their expected theoretical values.

  18. Physiological and proteome study of sunflowers exposed to a polymetallic constraint.

    PubMed

    Printz, Bruno; Sergeant, Kjell; Guignard, Cedric; Renaut, Jenny; Hausman, Jean-Francois

    2013-06-01

    The new energy requirements of the growing world population together with the actual ecological trend of phytoremediation have made challenging the cultivation of energetic crops on nonagricultural lands, such as those contaminated with trace elements. In this study, phenotypical characterization and biochemical analyses were combined to emphasize the global response of young sunflowers (Helianthus annuus L.) grown in hydroponic media contaminated with different Cd, Ni, and Zn concentrations. Leaves and roots of sunflowers reaching the stage "2-extended leaves" and exposed to different trace metal concentrations were harvested and analyzed by 2D-DIGE in order to study in depth the molecular responses of the young plants upon the polymetallic exposure. Proteomics confirmed the observed global reduction in growth and development. If photosynthetic light reactions and carbon metabolism were the most affected in leaves, in roots significant disruptions were observed in proteins involved in respiration, oxidative balance, protein and gene expression, and in the induction of programmed cell death. Elemental analyses of the plantlets indicated a profound impact of the treatment resulting in misbalance in essential micronutrients. Altogether, this study highlights the sensitivity of the sunflower to a polymetallic pollution and indicates that its use as a remediative tool of trace element polluted soils is limited.

  19. Identifying organic-rich Marcellus Shale lithofacies by support vector machine classifier in the Appalachian basin

    NASA Astrophysics Data System (ADS)

    Wang, Guochang; Carr, Timothy R.; Ju, Yiwen; Li, Chaofeng

    2014-03-01

    Unconventional shale reservoirs as the result of extremely low matrix permeability, higher potential gas productivity requires not only sufficient gas-in-place, but also a high concentration of brittle minerals (silica and/or carbonate) that is amenable to hydraulic fracturing. Shale lithofacies is primarily defined by mineral composition and organic matter richness, and its representation as a 3-D model has advantages in recognizing productive zones of shale-gas reservoirs, designing horizontal wells and stimulation strategy, and aiding in understanding depositional process of organic-rich shale. A challenging and key step is to effectively recognize shale lithofacies from well conventional logs, where the relationship is very complex and nonlinear. In the recognition of shale lithofacies, the application of support vector machine (SVM), which underlies statistical learning theory and structural risk minimization principle, is superior to the traditional empirical risk minimization principle employed by artificial neural network (ANN). We propose SVM classifier combined with learning algorithms, such as grid searching, genetic algorithm and particle swarm optimization, and various kernel functions the approach to identify Marcellus Shale lithofacies. Compared with ANN classifiers, the experimental results of SVM classifiers showed higher cross-validation accuracy, better stability and less computational time cost. The SVM classifier with radius basis function as kernel worked best as it is trained by particle swarm optimization. The lithofacies predicted using the SVM classifier are used to build a 3-D Marcellus Shale lithofacies model, which assists in identifying higher productive zones, especially with thermal maturity and natural fractures.

  20. Upper Cenozoic organic-rich sequences (offshore and onshore the south Aegean sea)

    SciTech Connect

    Anastasakis, G.

    1988-08-01

    The upper Cenozoic sedimentary column of the south Aegean Sea is composed mostly of marine sediments which have been deposited after the Seravallian breakup of the south Aegean landmass. Extensive submarine coring has revealed the frequent occurrence of Quaternary dark, organic-rich layers in the cores retrieved from water depths greater than 180 m. Moreover, deep-sea drilling (DSDP leg 42A) in the south Aegean basin recovered organic-rich layers as old as late Miocene. Onshore the south Aegean Sea islands, organic-rich sediments are found at the north and south territories of the region, on Milos and Crete islands. Especially on the island of Crete and south of it, on the smaller islands of Gavdos and Koufonisi, these organic-rich sediments represent a considerable portion of the widespread upper Cenozoic sediments. Stratigraphically they cover the interval between upper Seravallian and lower Pleistocene. The organic carbon content of all these mostly calcareous lithofacies, the so-called sapropels, ranges mostly between 0.5 and 6.5%. The most reliably chronostratigraphically correlated upper Pleistocene sapropels display similar compositional characteristics across the entire basin. Certain Pleistocene and older organic-rich layers contain increased proportions of siliceous tests. However the entire range of sapropels in the region (except those within the Messinian evaporites) can be described adequately by the same lithofacies association. To demonstrate this the authors compare the lower Tortonian Faneromeni Formation on Crete with the upper Quaternary sediments from the south Aegean Sea.

  1. Polymetallic reforming catalysts and their preparation

    SciTech Connect

    Baird, W.C. Jr.

    1989-03-14

    This patent describes a catalyst useful for reforming a naphtha feed at reforming conditions comprising an iridium component in concentration ranging from about 0.001 percent to about 2 percent dispersed throughout, and bound within an alumina support matrix by calcining the iridium-alumina composite at temperature ranging from about 370/sup 0/C to about 700/sup 0/C for a period ranging from about 1 hour to about 72 hours. It also has a platinum component, in concentration ranging from about 0.001 percent to about 2 percent, dispersed upon the iridium-containing alumina support; and a halogen component dispersed thereon in concentration ranging from about 0.01 percent to about 2 percent, based on the total weight of the catalyst. The iridium component is dispersed throughout and bound within the alumina support even when the composition is subjected to temperatures ranging above about 426.7/sup 0/C at oxygen concentrations ranging above about 0.1 percent, based on the volume of the gas contacted with the catalyst, for periods ranging from about 1 hour to about 48 hours.

  2. Generation of oil-like pyrolyzates from organic-rich shales.

    PubMed

    Lewan, M D; Winters, J C; McDonald, J H

    1979-03-02

    Pyrolyzates similar to natural crude oils were generated from organic-rich shales by hydrous pyrolysis. With this type of pyrolysis it is possible to make more sophisticated correlations between crude oils and their source rocks, evaluate the hydrocarbon potential of a source rock, and elucidate the variables involved in the natural oil-generating process.

  3. The Bartonian organic-rich deposits within the Silesian Basin (Polish Outer Carpathians)

    NASA Astrophysics Data System (ADS)

    Waskowska, Anna; Golonka, Jan; Bębenek, Sławomir; Cieszkowski, Marek; Chodyń, Rafał; Kaminski, Michael

    2016-04-01

    conditions were favorable for preserving organic matter, which was supplied to the basin floor and secured against wash-out and dilution. These conditions were fulfilled during the sedimentation of the Bartonian organic-rich deposits, which suggests the lithological development predominated by mudstones and siltstones, occurring in particular within thin layers of bentonites. The Bartonian organic-rich deposits occur within the upper part of the so-called Hieroglyphic Beds and form a relatively thick complex measuring 20m in thickness. They are clearly separated from the Menilite Formation by 40 m thick deposits of grey-green shales with sandstones belonging to the upper Bartonian - Priabonian Hieroglyphic Beds and the light marly shales, marls and marly limestones of the Priabonian Globigerina Marls Formation. The anoxic conditions lasted about 4-5 million years. This research has been financially supported by Micropress Europe Foundation and AGH University of Science and Technology in Krakow grant no. 11.11.140.173, NCBiR Blue Gas grant no. 17.17.140.87330.

  4. Early transcriptomic response of Arabidopsis thaliana to polymetallic contamination: implications for the identification of potential biomarkers of metal exposure.

    PubMed

    Gómez-Sagasti, María T; Barrutia, Oihana; Ribas, Griselda; Garbisu, Carlos; Becerril, José M

    2016-05-01

    Heavy metal contaminated sites are frequently characterized by the simultaneous presence of several heavy metals. However, many studies report metal-induced plant responses after long-term exposure to just one metal. By contrast, whole genome expression microarrays were employed here to investigate the early (3 h) transcriptional responses of Arabidopsis thaliana plants exposed to polymetallic treatment (Pb, Hg, Cu, Cd, Co, Ni, Zn, and Mn) at low (L) and high (H) concentrations. After 3 h of exposure to polymetallic treatment, a total of 1315 noticeably (≥2-fold) and significantly (P < 0.05) differentially expressed genes were identified: 656 and 351 upregulated and 314 and 200 downregulated genes in L and H treatments, respectively. Functional analysis revealed that many genes involved in oxidative stress and perception/signalling/regulation systems were activated. Genes encoding proteins involved in hormone regulation (jasmonic acid, abscisic acid, ethylene, and auxins), glucosinolate metabolism and sulphur and nitrogen transport were also modulated. RT-qPCR analysis of four downregulated (AOP2, SAUR16, BBX31, and MTPC3) and upregulated genes (ASN1, DIN2, BT2, and EXL5), markedly responsive to both L and H treatments, validated our microarray data and suggested the potential of some of these genes (AOP2, SAUR16, ASN1, and DIN2) as early biomarkers of metal exposure. Relevant changes in gene expression occur as early as 3 h after exposure to polymetallic treatment. Four genes deserve further studies as novel putative biomarkers of early metal exposure and also owing to their potential implications in stress-related mechanisms: sulphur balance (AOP2), phytohormone regulation of plant growth and development (SAUR16), ammonium detoxification (ASN1) and senescence (DIN2).

  5. Calcium isotope evidence for suppression of carbonate dissolution in carbonate-bearing organic-rich sediments

    NASA Astrophysics Data System (ADS)

    Turchyn, Alexandra V.; DePaolo, Donald J.

    2011-11-01

    sites (the actual rates could be significantly slower) because other processes that impact the calcium isotope composition of sedimentary pore fluid have not been included. The results provide direct geochemical evidence for the anecdotal observation that the best-preserved carbonate fossils are often found in clay or organic-rich sedimentary horizons. The results also suggest that the presence of clay minerals has a strong passivating effect on the surfaces of biogenic carbonate minerals, slowing dissolution dramatically even in relation to the already-slow rates typical of carbonate-rich sediments.

  6. Porphyry Cu-Au and associated polymetallic Fe-Cu-Au deposits in the Beiya Area, western Yunnan Province, south China

    USGS Publications Warehouse

    Xu, X.-W.; Cai, X.-P.; Xiao, Q.-B.; Peters, S.G.

    2007-01-01

    The Alkaline porphyries in the Beiya area are located east of the Jinshajiang suture, as part of a Cenozoic alkali-rich porphyry belt in western Yunnan. The main rock types include quartz-albite porphyry, quartz-K-feldspar porphyry and biotite-K-feldspar porphyry. These porphyries are characterised by high alkalinity [(K2O + Na2O)% > 10%], high silica (SiO2% > 65%), high Sr (> 400??ppm) and 87Sr/86Sr (> 0.706)] ratio and were intruded at 65.5??Ma, between 25.5 to 32.5??Ma, and about 3.8??Ma, respectively. There are five main types of mineral deposits in the Beiya area: (1) porphyry Cu-Au deposits, (2) magmatic Fe-Au deposits, (3) sedimentary polymetallic deposits, (4) polymetallic skarn deposits, and (5) palaeoplacers associated with karsts. The porphyry Cu-Au and polymetallic skarn deposits are associated with quartz-albite porphyry bodies. The Fe-Au and polymetallic sedimentary deposits are part of an ore-forming system that produced considerable Au in the Beiya area, and are characterised by low concentrations of La, Ti, and Co, and high concentrations of Y, Yb, and Sc. The Cenozoic porphyries in western Yunnan display increased alkalinity away from the Triassic Jinshajiang suture. Distribution of both the porphyries and sedimentary deposits in the Beiya area are interpreted to be related to partial melting in a disjointed region between upper mantle lithosphere of the Yangtze Plate and Gondwana continent, and lie within a shear zone between buried Palaeo-Tethyan oceanic lithosphere and upper mantle lithosphere, caused by the subduction and collision of India and Asia. ?? 2006 Elsevier B.V. All rights reserved.

  7. Stratigraphy and depositional settings of Cretaceous organic-rich sequences in the Brazilian marginal basins

    SciTech Connect

    Mello, M.R.; Koutsoukos, E.A.M.; Santos Neto, E.V. )

    1991-03-01

    A comprehensive geochemical and paleontological survey of the stratigraphic framework and depositional setting of the organic-rich and most prolific petroleum source rocks sequences in the Brazilian marginal basins has been undertaken. The geochemical analysis of the rocks included organic carbon determinations, Rock-Eval pyrolysis, carbon and hydrogen isotope measurements, porphyrin analysis, and biological markers investigations, using chromatography-mass spectrometry/mass spectrometry (GC-MS/MS) of the saturate and aromatic fractions. The paleontological study involved the assessment of the distribution and diversity patterns of microfossils (foraminifers, radiolarians, diatoms and ostracods), calcareous nannofossils, and palynomorphs in dating and paleoenvironmental assignments. The results demonstrate the importance of the integration of geochemical and paleontological data for both characterization and lateral and vertical correlations of organic-rich sequences. Furthermore, such an approach is a powerful tool in ascertaining types of depositional environment and age constraints within different petroleum stratigraphic frameworks.

  8. Bacteria Contribute to Sediment Nutrient Release and Reflect Progressed Eutrophication-Driven Hypoxia in an Organic-Rich Continental Sea

    PubMed Central

    Sinkko, Hanna; Lukkari, Kaarina; Sihvonen, Leila M.; Sivonen, Kaarina; Leivuori, Mirja; Rantanen, Matias; Paulin, Lars; Lyra, Christina

    2013-01-01

    In the sedimental organic matter of eutrophic continental seas, such as the largest dead zone in the world, the Baltic Sea, bacteria may directly participate in nutrient release by mineralizing organic matter or indirectly by altering the sediment’s ability to retain nutrients. Here, we present a case study of a hypoxic sea, which receives riverine nutrient loading and in which microbe-mediated vicious cycles of nutrients prevail. We showed that bacterial communities changed along the horizontal loading and vertical mineralization gradients in the Gulf of Finland of the Baltic Sea, using multivariate statistics of terminal restriction fragments and sediment chemical, spatial and other properties of the sampling sites. The change was mainly explained by concentrations of organic carbon, nitrogen and phosphorus, which showed strong positive correlation with Flavobacteria, Sphingobacteria, Alphaproteobacteria and Gammaproteobacteria. These bacteria predominated in the most organic-rich coastal surface sediments overlain by oxic bottom water, whereas sulphate-reducing bacteria, particularly the genus Desulfobacula, prevailed in the reduced organic-rich surface sediments in the open sea. They correlated positively with organic nitrogen and phosphorus, as well as manganese oxides. These relationships suggest that the bacterial groups participated in the aerobic and anaerobic degradation of organic matter and contributed to nutrient cycling. The high abundance of sulphate reducers in the surficial sediment layers reflects the persistence of eutrophication-induced hypoxia causing ecosystem-level changes in the Baltic Sea. The sulphate reducers began to decrease below depths of 20 cm, where members of the family Anaerolineaceae (phylum Chloroflexi) increased, possibly taking part in terminal mineralization processes. Our study provides valuable information on how organic loading affects sediment bacterial community compositions, which consequently may maintain active

  9. Bacteria contribute to sediment nutrient release and reflect progressed eutrophication-driven hypoxia in an organic-rich continental sea.

    PubMed

    Sinkko, Hanna; Lukkari, Kaarina; Sihvonen, Leila M; Sivonen, Kaarina; Leivuori, Mirja; Rantanen, Matias; Paulin, Lars; Lyra, Christina

    2013-01-01

    In the sedimental organic matter of eutrophic continental seas, such as the largest dead zone in the world, the Baltic Sea, bacteria may directly participate in nutrient release by mineralizing organic matter or indirectly by altering the sediment's ability to retain nutrients. Here, we present a case study of a hypoxic sea, which receives riverine nutrient loading and in which microbe-mediated vicious cycles of nutrients prevail. We showed that bacterial communities changed along the horizontal loading and vertical mineralization gradients in the Gulf of Finland of the Baltic Sea, using multivariate statistics of terminal restriction fragments and sediment chemical, spatial and other properties of the sampling sites. The change was mainly explained by concentrations of organic carbon, nitrogen and phosphorus, which showed strong positive correlation with Flavobacteria, Sphingobacteria, Alphaproteobacteria and Gammaproteobacteria. These bacteria predominated in the most organic-rich coastal surface sediments overlain by oxic bottom water, whereas sulphate-reducing bacteria, particularly the genus Desulfobacula, prevailed in the reduced organic-rich surface sediments in the open sea. They correlated positively with organic nitrogen and phosphorus, as well as manganese oxides. These relationships suggest that the bacterial groups participated in the aerobic and anaerobic degradation of organic matter and contributed to nutrient cycling. The high abundance of sulphate reducers in the surficial sediment layers reflects the persistence of eutrophication-induced hypoxia causing ecosystem-level changes in the Baltic Sea. The sulphate reducers began to decrease below depths of 20 cm, where members of the family Anaerolineaceae (phylum Chloroflexi) increased, possibly taking part in terminal mineralization processes. Our study provides valuable information on how organic loading affects sediment bacterial community compositions, which consequently may maintain active

  10. Critical shear stress for mass erosion of organic-rich fine sediments

    NASA Astrophysics Data System (ADS)

    Mehta, Ashish J.; Hwang, Kyu-Nam; Khare, Yogesh P.

    2015-11-01

    In shallow lakes of Florida laden with low-strength organic-rich sediments, wind-induced water movement is believed to actuate bed surface erosion as well as mass erosion. Experiments in hydraulic flumes to measure the critical shear stress for mass erosion tend to be lengthy and require large quantities of sediment. For bottom sediment from Lake Okeechobee at naturally occurring values of the floc volume fraction, a comparison of the viscoplastic yield stress, readily obtained from rheometry, with the mass erosion critical stress from flume tests indicates that it may be permissible to consider the yield stress as a surrogate for the critical stress. This inference appears to be supported by ancillary observations from Lake Apopka and Newnans Lake. Interestingly enough, the variation of yield stress with the floc volume fraction of the organic-rich bed is found to conform to fractal characterization commonly invoked for mineral sediment flocs, consistent with a representative constant value of 2.55 of the fractal dimension. Pending fuller investigations with a wide range of organic-rich sediments, recourse to rheometry in lieu of flume experiments holds promise as a means to simplify testing requirements for estimating the mass erosion critical stress.

  11. Geochemistry, paleoenvironment and timing of Lower Aptian organic rich beds of Paja Formation (Eastern Cordillera, Colombia)

    NASA Astrophysics Data System (ADS)

    Gaona Narvaez, T.; Maurrasse, F. J.; Etayo Serna, F.

    2011-12-01

    High-resolution analyses were carried out on two sections of the Colombian Eastern Cordillera to determine the stratigraphic and geochemical relationship between some Aptian-age organic-rich levels within the Paja Fm and the Oceanic Anoxic Event 1a. These analyses included: petrography, total inorganic carbon (TIC, wt% CaCO3), total organic carbon (TOC, wt% C), stable carbon isotopes in the organic matter (δ13Corg), and ammonite biostratigraphy. In a global context, the Lower Aptian organic-rich marine sediments are believed to include an episode of anoxia referred as the "Oceanic Anoxic Event 1a" (OAE-1a), which correlates with δ13C stages C3 to C6, and had a duration of about 1.0 to 1.3 MA [1,2]. At the Villa de Leiva section (Tunja-Villa de Leiva road), a 115 m succession of the Paja Fm Arcillolitas Abigarradas Member was studied. At this locality the unit has a prominent 4m-thick interval of black shale, ten meters below the base of the lowest Upper Aptian (Gargasian) Dufrenoyia sanctorum-Stoyanowiceras treffryanus ammonite assemblage zone [3]. Similarly, at Curiti Quarry (San Gil-Curiti road), a 12 m section includes an 8 m-thick organic-rich shale at the basal interval of the Paja Fm. At this locality the succession overlies the Barremian-age carbonate ramp deposits of the Rosablanca Fm; and the base of the Paja Fm yielded a reworked and phosphatized assemblage of middle Barremian to lowest Aptian ammonites of the genera Pulchellia, Gerhardtia, Toxancycloceras, Karsteniceras and Prodeshayesites. At Villa de Leiva, the 4 m-thick interval of TOC-rich clay-shale and marlstones (191.6 m to 195.5 m), shows horizontal laminae associated with gypsum, absence of bioturbation and benthic fossils, and presence of pyritic concretions. At this locality the studied interval has TOC values between 1.17% and 5.33%; and the Fm Paja is interpreted as have been deposited under anoxic conditions in a subtidal, hypersaline environment. Carbon isotope data below the base of the

  12. Role of microbial processes in linking sandstone diagenesis with organic-rich clays

    USGS Publications Warehouse

    McMahon, P.B.; Chapelle, F.H.; Falls, W.F.; Bradley, P.M.

    1992-01-01

    Shows that the processes of microbial organic-acid production (via fermentation) in clays and microbial organic-acid consumption (via sulfate reduction) in sands effectively link organic-rich clays to sandstone diagenesis in the Black Creek Formation of South Carolina. Diagenetic processes have resulted in the formation of 10 volume percent calcite cement, 0.1 volume percent authigenic pyrite, and 1.5 volume percent secondary porosity in Black Creek sands. However, the distribution of these diagenetic processes is not uniform, resulting in net destruction of porosity in some parts of the sand and net porosity enchancement in other parts. -from Authors

  13. Integrated depositional model for the Cenomanian Turonian organic-rich strata in North Africa

    NASA Astrophysics Data System (ADS)

    Lüning, S.; Kolonic, S.; Belhadj, E. M.; Belhadj, Z.; Cota, L.; Barić, G.; Wagner, T.

    2004-01-01

    During the Late Cenomanian-Early Turonian (C/T) Oceanic Anoxic Event (OAE2), organic-rich strata was deposited in rift shelf basins and slopes across North Africa and in deep-sea basins of the adjacent oceans. Based on a review of published and unpublished information, this paper documents the distribution and organic-richness of C/T strata across the whole region within a palaeogeographic framework and systematically analyses the conditions and processes, which controlled their deposition. Previously, the C/T in North Africa has been most intensively studied in southern Morocco (Tarfaya) and Tunisia. Only little data is availabe for other parts of North Africa, namely Algeria, Libya and Egypt, because distribution of C/T Corg strata there becomes more patchy. A general decrease in peak organic richness and black shale thickness occurs from west to east, partly as a result of upwelling along the Moroccan Atlantic coast and the absence of upwelling in the eastern Mediterranean area. Furthermore, in the confined central Atlantic, the oxygen minimum zone (OMZ) in many places reached down to the deep-sea floor (3-4 km), while the lower limit of the OMZ along the North African Tethys was much shallower and underlain by oxic water masses. As documented by high resolution biostratigraphic and chemostratigraphic data, C/T black shale deposition in most areas outside the upwelling zone are restricted to a strong, eustatic, latest Cenomanian transgressive phase. Triggered by this sea-level rise, the OMZ impinged onto the North African continental shelf and the margins of intrashelf basins, which mostly formed during the Early Cretaceous as halfgrabens. Important units containing C/T organic-rich strata in the region are the Atlantic Tarfaya black shales (Morocco, Western Sahara), black shales and phtanites in the Moroccan and Algerian Atlas, the Bahloul Fm. in the SE Constantine Basin and in northern and central Tunisia, the Etel Fm. in the Sirte Basin, the Al Hilal Fm. in

  14. The aqueous geochemistry of uranium in a drainage containing uraniferous organic-rich sediments, Lake Tahoe area, Nevada, USA

    USGS Publications Warehouse

    Zielinski, R.A.; Otton, J.K.; Wanty, R.B.; Pierson, C.T.

    1988-01-01

    Anomalously uraniferous waters occur in a small (4.2 km2) drainage in the west-central Carson Range, Nevada, on the eastern side of Lake Tahoe. The waters transport uranium from local U-rich soils and bedrock to organic-rich valley-fill sediments where it is concentrated, but weakly bound. The dissolved U and the U that is potentially available from coexisting sediments pose a threat to the quality of drinking water that is taken from the drainage. The U concentration in samples of 6 stream, 11 spring and 7 near-surface waters ranged from 0.1 V). Possible precipitation of U(IV) minerals is predicted under the more reducing conditions that are particularly likely in near-surface waters, but the inhibitory effects of sluggish kinetics or organic complexing are not considered. These combined results suggest that a process such as adsorption or ion exchange, rather than mineral saturation, is the most probable mechanism for uranium fixation in the sediments. -Authors

  15. Transformation of polymetallic dust in the organic horizon of Al-Fe-humus podzol (field experiment)

    NASA Astrophysics Data System (ADS)

    Lyanguzova, I. V.; Goldvirt, D. K.; Fadeeva, I. K.

    2015-07-01

    Scanning electron microscopy with an X-ray spectral microanalysis showed that the ash matter from the organic horizons (after ignition) of control and experimental plots mainly (>85%) consists of different soil-forming minerals and iron oxides (particularly magnetite). From 10% to 15% of particles in the organic horizon of Al-Fe-humus podzol (Albic Rustic Podzol) of the experimental plot were represented by polymetallic ball-shaped dust particles that were preserved in the soil without significant transformation for 14 years after their artificial application. The total contents of Cu, Pb, As, and Ni in the organic horizon on the experimental plot were 22-100 times higher than those in the control; the contents of Zn and Fe were 2-5 times higher. The sequence of chemical elements according to their total contents in the samples of control and experimental plots was different. The portion of available forms of heavy metal (Ni, Cu, and Co) compounds extractable with 1.0 M HCl averaged 20-30% of their total contents in the soil. More than 80% of acid-soluble forms of heavy metals were concentrated in the organic horizon of contaminated podzol soil, which represents the biogeochemical barrier to the migration of pollutants down the soil profile. Durable fixation of heavy metals in the organic horizon and their weak migration into the mineral soil layers significantly hamper the processes of self-purification of contaminated soils.

  16. Comparison of formation mechanism of fresh-water and salt-water lacustrine organic-rich shale

    NASA Astrophysics Data System (ADS)

    Lin, Senhu

    2017-04-01

    Based on the core and thin section observation, major, trace and rare earth elements test, carbon and oxygen isotopes content analysis and other geochemical methods, a detailed study was performed on formation mechanism of lacustrine organic-rich shale by taking the middle Permian salt-water shale in Zhungaer Basin and upper Triassic fresh-water shale in Ordos Basin as the research target. The results show that, the middle Permian salt-water shale was overall deposited in hot and dry climate. Long-term reductive environment and high biological abundance due to elevated temperature provides favorable conditions for formation and preservation of organic-rich shale. Within certain limits, the hotter climate, the organic-richer shale formed. These organic-rich shale was typically distributed in the area where palaeosalinity is relatively high. However, during the upper Triassic at Ordos Basin, organic-rich shale was formed in warm and moist environment. What's more, if the temperature, salinity or water depth rises, the TOC in shale decreases. In other words, relatively low temperature and salinity, stable lake level and strong reducing conditions benefits organic-rich shale deposits in fresh water. In this sense, looking for high-TOC shale in lacustrine basin needs to follow different rules depends on the palaeoclimate and palaeoenvironment during sedimentary period. There is reason to believe that the some other factors can also have significant impact on formation mechanism of organic-rich shale, which increases the complexity of shale oil and gas prediction.

  17. No bolide impact trace for OJP volcanism that triggered Early Cretaceous anoxia event: PGE evidence from coeval organic-rich sediments, central Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Tejada, M. G.; Nozaki, T.; Ishikawa, A.; Senda, R.; Suzuki, K.; Kimura, J.

    2010-12-01

    Marine deposits of organic-rich sediments that represent the Early Cretaceous oceanic anoxic event, OAE 1a, are found at different sites globally. Previous study of the type section in Gorgo a Cerbara, central Italy, known as the Selli Level, showed that this event is also marked by a sharp decrease to unradiogenic values in the seawater Os isotope profile, indicating massive inputs from unradiogenic Os source. Both mantle and meteoritic inputs can account for the unradiogenic Os isotope signature of the organic-rich sediments because they have the same low 187Os/188Os values of 0.13 and the massive OJP eruption is also linked to both mantle plume and bolide impact origin. The platinum group element (PGE) abundances in sedimentary rocks deposited before and during the OJP emplacement can be used to assess the influence of mantle vs. extraterrestrial source on the origin of the plateau itself and on the marine oceanic anoxic event that happened contemporaneously ~120 my ago. If a bolide impact caused the emplacement of the OJP, traces of this event may have been preserved in marine sequences nearby but could have been diluted or absent from distant sites like the previously studied central Italy sections. In view of this, we investigated both the platinum group element and Os isotope variation at DSDP Site 463, central Pacific Ocean, ~2000 km away from the OJP. The PGE contents of the organic-rich sequence at Site 463 were analyzed and found to have Ir concentrations of 24-285 ppt, lower than the values for other known large impact horizons. These values fall within the range for Gorgo a Cerbara section. A 90-cm segment within the 10-meter organic-rich section yielded the highest Ir concentrations of 239-285 ppt but it does not coincide with the base of the Selli Level-equivalent interval. In addition, the organic-rich, Selli Level-equivalent horizon including the interval that yielded the highest concentration of Re and other PGEs have nonchondritic Os/Ir and Pt

  18. Green icebergs formed by freezing of organic-rich seawater to the base of Antarctic ice shelves

    NASA Technical Reports Server (NTRS)

    Warren, Stephen G.; Roesler, Collin S.; Morgan, Vincent I.; Brandt, Richard E.; Goodwin, Ian D.; Allison, Ian

    1993-01-01

    Samples of Antarctic seawater, basal ice, and green ice from ice cliffs and green icebergs are analyzed in order to examine green icebergs formed by the freezing of organic-rich seawater to the base of Antarctic ice shelves. Spectral reflectance of a green iceberg measured near 67 deg S, 62 deg E confirms that the color is inherent in the ice, not an artifact of the illumination. A constituent that absorbs blue photons is identified by spectrophotometric analysis of core samples from this iceberg and from the Amery basal ice, and of seawater samples from Prydz Bay off the Amery Ice Shelf. Analysis of the samples by fluorescence spectroscopy indicates that the blue absorption, and hence the inherent green color, is due to the presence of marine-derived organic matter in the green iceberg, basal ice, and seawater. Thick accumulations of green ice, in icebergs, and at the base of ice shelves indicate that high concentrations of organic matter exist in seawater for centuries at the depth of basal freezing.

  19. Contamination of soils near a tailing pond at the Zlate Hory polymetallic ore deposit

    SciTech Connect

    Raclavska, H.; Raclavska, K.

    1994-12-31

    The relationship between concentrations of trace elements in soils and their content in plants has became a frequently discussed issue. Attention also focuses on the effects of trace element concentrations on the healthy development of vegetation. The Zlate Hory Mining District (in the northern part of the Jeseniky Mountains, 14 km east of Jesenik) with its polymetallic mineral deposits represents an important geochemical source area. It provides opportunities for the study of trace element distributions in the soil horizons and vegetation of a forest comprising mainly Norway spruce, Picea abies (L.) Karsten. Conditions of geochemical migration vary widely from geochemical background to the anomalous areas affected by a high level of mining activity. Trace element distribution in soil horizons was studied in the flood plain of Prudnik Creek. The study area was delineated using basic square units, 10 x 10 m, alternated regularly with free squares. Soil sampling was performed inside the basic square units simultaneously with geobotanical mapping. The study area was located where soils of the flood plain are influenced by waters discharged from a tailing pond and by the highly contaminated waters of Prudnik Creek. The tailing pond is situated above the study area, on the western slope of the Prudnik valley. The mine and mineral dressing plant is located two kilometers upstream to the south. Flotation technology is used to produce chalcopyrite concentrate from ore of the disseminated type. Stratiform ore bodies formed by chalcopyrite and pyrite, with some admixtures of galena and sphalerite, are deposited in metamorphosed Devonian series with quartzite and phyllites predominant.

  20. Evaluating the Poroelastic Effect on Anisotropic, Organic-Rich, Mudstone Systems

    NASA Astrophysics Data System (ADS)

    Suarez-Rivera, Roberto; Fjær, Erling

    2013-05-01

    Understanding the poroelastic effect on anisotropic organic-rich mudstones is of high interest and value for evaluating coupled effects of rock deformation and pore pressure, during drilling, completion and production operations in the oilfield. These applications include modeling and prevention of time-dependent wellbore failure, improved predictions of fracture initiation during hydraulic fracturing operations (Suarez-Rivera et al. Presented at the Canadian Unconventional Resources Conference held in Calgary, Alberta, Canada, 15-17 November 2011. CSUG/SPE 146998 2011), improved understanding of the evolution of pore pressure during basin development, including subsidence and uplift, and the equilibrated effective in situ stress (Charlez, Rock mechanics, vol 2 1997; Katahara and Corrigan, Pressure regimes in sedimentary basins and their prediction: AAPG Memoir, vol 76, pp 73-78 2002; Fjær et al. Petroleum related rock mechanics. 2nd edn 2008). In isotropic rocks, the coupled poro-elastic deformations of the solid framework and the pore fluids are controlled by the Biot and Skempton coefficients. These are the two fundamental properties that relate the rock framework and fluid compressibility and define the magnitude of the poroelastic effect. In transversely isotropic rocks, one desires to understand the variability of these coefficients along the directions parallel and longitudinal to the principal directions of material symmetry (usually the direction of bedding). These types of measurements are complex and uncommon in low-porosity rocks, and particularly problematic and scarce in tight shales. In this paper, we discuss a methodology for evaluating the Biot's coefficient, its variability along the directions parallel and perpendicular to bedding as a function of stress, and the homogenized Skempton coefficient, also as a function of stress. We also predict the pore pressure change that results during undrained compression. Most importantly, we provide values

  1. Estimation of anisotropy parameters in organic-rich shale: Rock physics forward modeling approach

    NASA Astrophysics Data System (ADS)

    Herawati, Ida; Winardhi, Sonny; Priyono, Awali

    2015-09-01

    Anisotropy analysis becomes an important step in processing and interpretation of seismic data. One of the most important things in anisotropy analysis is anisotropy parameter estimation which can be estimated using well data, core data or seismic data. In seismic data, anisotropy parameter calculation is generally based on velocity moveout analysis. However, the accuracy depends on data quality, available offset, and velocity moveout picking. Anisotropy estimation using seismic data is needed to obtain wide coverage of particular layer anisotropy. In anisotropic reservoir, analysis of anisotropy parameters also helps us to better understand the reservoir characteristics. Anisotropy parameters, especially ɛ, are related to rock property and lithology determination. Current research aims to estimate anisotropy parameter from seismic data and integrate well data with case study in potential shale gas reservoir. Due to complexity in organic-rich shale reservoir, extensive study from different disciplines is needed to understand the reservoir. Shale itself has intrinsic anisotropy caused by lamination of their formed minerals. In order to link rock physic with seismic response, it is necessary to build forward modeling in organic-rich shale. This paper focuses on studying relationship between reservoir properties such as clay content, porosity and total organic content with anisotropy. Organic content which defines prospectivity of shale gas can be considered as solid background or solid inclusion or both. From the forward modeling result, it is shown that organic matter presence increases anisotropy in shale. The relationships between total organic content and other seismic properties such as acoustic impedance and Vp/Vs are also presented.

  2. Estimation of anisotropy parameters in organic-rich shale: Rock physics forward modeling approach

    SciTech Connect

    Herawati, Ida Winardhi, Sonny; Priyono, Awali

    2015-09-30

    Anisotropy analysis becomes an important step in processing and interpretation of seismic data. One of the most important things in anisotropy analysis is anisotropy parameter estimation which can be estimated using well data, core data or seismic data. In seismic data, anisotropy parameter calculation is generally based on velocity moveout analysis. However, the accuracy depends on data quality, available offset, and velocity moveout picking. Anisotropy estimation using seismic data is needed to obtain wide coverage of particular layer anisotropy. In anisotropic reservoir, analysis of anisotropy parameters also helps us to better understand the reservoir characteristics. Anisotropy parameters, especially ε, are related to rock property and lithology determination. Current research aims to estimate anisotropy parameter from seismic data and integrate well data with case study in potential shale gas reservoir. Due to complexity in organic-rich shale reservoir, extensive study from different disciplines is needed to understand the reservoir. Shale itself has intrinsic anisotropy caused by lamination of their formed minerals. In order to link rock physic with seismic response, it is necessary to build forward modeling in organic-rich shale. This paper focuses on studying relationship between reservoir properties such as clay content, porosity and total organic content with anisotropy. Organic content which defines prospectivity of shale gas can be considered as solid background or solid inclusion or both. From the forward modeling result, it is shown that organic matter presence increases anisotropy in shale. The relationships between total organic content and other seismic properties such as acoustic impedance and Vp/Vs are also presented.

  3. Biogeochemical response of organic-rich freshwater marshes in the Louisiana delta plain to chronic river water influx

    USGS Publications Warehouse

    Swarzenski, C.M.; Doyle, T.W.; Fry, B.; Hargis, T.G.

    2008-01-01

    To help evaluate effects of Mississippi River inputs to sustainability of coastal Louisiana ecosystems, we compared porewater and substrate quality of organic-rich Panicum hemitomon freshwater marshes inundated by river water annually for more than 30 years (Penchant basin, PB) or not during the same time (Barataria basin, BB). In the marshes receiving river water the soil environment was more reduced, the organic substrate was more decomposed and accumulated more sulfur. The porewater dissolved ammonium and orthophosphate concentrations were an order of magnitude higher and sulfide and alkalinity concentrations were more than twice as high in PB compared with BB marshes. The pH was higher and dissolved iron concentrations were more than an order of magnitude lower in PB marshes than in BB marshes. The influx of nutrient-rich river water did not enhance end-of-year above-ground standing biomass or vertical accretion rates of the shallow substrate. The differences in porewater chemistry and substrate quality are reasonably linked to the long-term influx of river water through biogeochemical processes and transformations involving alkalinity, nitrate and sulfate. The key factor is the continual replenishment of alkalinity, nitrate and sulfate via overland flow during high river stage each year for several weeks to more than 6 months. This leads to a reducing soil environment, pooling of the phytotoxin sulfide and inorganic nutrients in porewater, and internally generated alkalinity. Organic matter decomposition is enhanced under these conditions and root mats degraded. The more decomposed root mat makes these marshes more susceptible to erosion during infrequent high-energy events (for example hurricanes) and regular low-energy events, such as tides and the passage of weather fronts. Our findings were unexpected and, if generally applicable, suggest that river diversions may not be the beneficial mitigating agent of wetland restoration and conservation that they are

  4. Au-Ag polymetallic mineralization within tectonically weak zones along the southwestern edge of the Colorado Plateau

    SciTech Connect

    Wenrich, K.J.; Silberman, M.L. )

    1993-04-01

    The Music Mountain mining district lies at the base of the Grand Wash Cliffs, a major fault-line scarp along the Grand Wash fault, which marks the SW margin of the Colorado Plateau. Nearly vertical Au-Ag polymetallic quartz veins parallel, and are in contact with, altered diabase and granite porphyry dikes that cut Proterozoic granite, schist, and gneiss. The gold-bearing veins range in thickness from an inch to several feet and contain significant amounts of sulfide minerals. Diabase dikes and quartz veins in the district and to the north consistently strike N42[degree]W to N57[degree]W, which is one of the most prevalent fracture orientation throughout NW Arizona. In the Gold Basin-Lost Basin districts to the north, the Au occurs in such pegmatite-quartz veins that strike NE. Thirty miles east along Diamond Creek, quartz veins and diabase dikes strike N45[degree]E and are associated with Au and Ag anomalies in stream-sediments and panned concentrates. To the west major Au-Ag polymetallic quartz veins of the Wallapai mining district show consistent strikes from N30[degree] to 60[degree]W. K-Ar ages of hydrothermal alterations of 4 NW oriented diabase dikes that have quartz veins along them, range from 935 [+-] 35 to 755 [+-] 21 Ma. Sericite from altered granite porphyry, adjacent to a mineralized vein, gave a K-Ar age of 72 [+-]2 Ma. All geochemical sites (within a 1,000 mi[sup 2] area) determined to be anomalous in Au lie within 2 mi of either the Grand Wash or Hurricane faults. The Hurricane and Grand Wash faults, major Precambrian fault zones that were reactivated in the Phanerozoic, appear to be good exploration targets for Au-rich quartz veins associated with pegmatite or diabase dikes, many of which may be buried beneath the thick alluvium of Hualapai Valley.

  5. The Eagle Ford Shale, Texas: an initial insight into Late Cretaceous organic-rich mudrock palaeoenvironments

    NASA Astrophysics Data System (ADS)

    Forshaw, Joline; Jarvis, Ian; Trabucho-Alexandre, João; Tocher, Bruce; Pearce, Martin

    2014-05-01

    The hypothesised reduction of oxygen within the oceans during the Cretaceous is believed to have led to extended intervals of regional anoxia in bottom waters, resulting in increased preservation of organic matter and the deposition of black shales. Episodes of more widespread anoxia, and even euxinia, in both bottom and surface waters are associated with widespread black shale deposition during Ocean Anoxic Events (OAEs). The most extensive Late Cretaceous OAE, which occurred ~ 94 Ma during Cenomanian-Turonian boundary times, and was particularly well developed in the proto-North Atlantic and Tethyan regions, lasted for around 500 kyr (OAE2). Although the causes of this and other events are still hotly debated, research is taking place internationally to produce a global picture of the causes and consequences of Cretaceous OAEs. Understanding OAEs will enable a better interpretation of the climate fluctuations that ensued, and their association with the widespread deposition of black shales, rising temperatures, increased pCO2, enhanced weathering, and increased nutrient fluxes. The Eagle Ford Formation, of Cenomanian - Turonian age, is a major shale gas play in SW and NE Texas, extending over an area of more than 45,000 km2. The formation, which consists predominantly of black shales (organic-rich calcareous mudstones), was deposited during an extended period of relative tectonic quiescence in the northern Gulf Coast of the Mexico Basin, bordered by reefs along the continental shelf. The area offers an opportunity to study the effects of OAE2 in an organic-rich shelf setting. The high degree of organic matter preservation in the formation has produced excellent oil and gas source rocks. Vast areas of petroleum-rich shales are now being exploited in the Southern States of the US for shale gas, and the Eagle Ford Shale is fast becoming one of the countries largest producers of gas, oil and condensate. The Eagle Ford Shale stratigraphy is complex and heterogeneous

  6. Gold nanorod-templated synthesis of polymetallic hollow nanostructures with enhanced electrocatalytic performance

    NASA Astrophysics Data System (ADS)

    Guo, Xia; Ye, Wei; Zhu, Rui; Wang, Wenxin; Xie, Fang; Sun, Hongyan; Zhao, Qing; Ding, Yi; Yang, Jian

    2014-09-01

    Anisotropic polymetallic hollow nanostructures are highly desired for many applications because of their unique morphology, large specific surface areas and attractive electronic effects. Here, a simple method using gold nanorods as a self-sacrificed template has been developed for the fabrication of hollow dumbbell-like nanorods of Au@PtAg. The formation of the hollow structures involves the growth of another metallic shell first, and then the etching of gold nanorods, which is induced by oxygen and ascorbic acid. The lattice mismatch and cohesive energy of the shell, along with its surface passivation, greatly affect the subsequent etching and the resulting products, as has been demonstrated by a positive control in the case of Rh and a negative control in the case of Pd. Hollow dumbbell-like nanorods of Au@PtAg show great enhancement for the dehydrogenation pathway in the oxidation of formic acid, as compared to solid Au@PtAg nanorods, PtAu nanotubes and commercial Pt/C.Anisotropic polymetallic hollow nanostructures are highly desired for many applications because of their unique morphology, large specific surface areas and attractive electronic effects. Here, a simple method using gold nanorods as a self-sacrificed template has been developed for the fabrication of hollow dumbbell-like nanorods of Au@PtAg. The formation of the hollow structures involves the growth of another metallic shell first, and then the etching of gold nanorods, which is induced by oxygen and ascorbic acid. The lattice mismatch and cohesive energy of the shell, along with its surface passivation, greatly affect the subsequent etching and the resulting products, as has been demonstrated by a positive control in the case of Rh and a negative control in the case of Pd. Hollow dumbbell-like nanorods of Au@PtAg show great enhancement for the dehydrogenation pathway in the oxidation of formic acid, as compared to solid Au@PtAg nanorods, PtAu nanotubes and commercial Pt/C. Electronic

  7. Chemistry of the organic-rich hot core G327.3-0.6

    NASA Technical Reports Server (NTRS)

    Gibb, E.; Nummelin, A.; Irvine, W. M.; Whittet, D. C.; Bergman, P.; Ferris, J. P. (Principal Investigator)

    2000-01-01

    We present gas-phase abundances of species found in the organic-rich hot core G327.3-0.6. The data were taken with the Swedish-ESO Submillimetre Telescope (SEST). The 1-3 mm spectrum of this source is dominated by emission features of nitrile species and saturated organics, with abundances greater than those found in many other hot cores, including Sgr B2 and OMC-1. Population diagram analysis indicates that many species (CH3CN, C2H3CN, C2H5CN, CH3OH, etc.) have hot components that originate in a compact (2") region. Gas-phase chemical models cannot reproduce the high abundances of these molecules found in hot cores, and we suggest that they originate from processing and evaporation of icy grain mantle material. In addition, we report the first detection of vibrationally excited ethyl cyanide and the first detection of methyl mercaptan (CH3SH) outside the Galactic center.

  8. Chemistry of the organic-rich hot core G327.3-0.6

    NASA Technical Reports Server (NTRS)

    Gibb, E.; Nummelin, A.; Irvine, W. M.; Whittet, D. C.; Bergman, P.; Ferris, J. P. (Principal Investigator)

    2000-01-01

    We present gas-phase abundances of species found in the organic-rich hot core G327.3-0.6. The data were taken with the Swedish-ESO Submillimetre Telescope (SEST). The 1-3 mm spectrum of this source is dominated by emission features of nitrile species and saturated organics, with abundances greater than those found in many other hot cores, including Sgr B2 and OMC-1. Population diagram analysis indicates that many species (CH3CN, C2H3CN, C2H5CN, CH3OH, etc.) have hot components that originate in a compact (2") region. Gas-phase chemical models cannot reproduce the high abundances of these molecules found in hot cores, and we suggest that they originate from processing and evaporation of icy grain mantle material. In addition, we report the first detection of vibrationally excited ethyl cyanide and the first detection of methyl mercaptan (CH3SH) outside the Galactic center.

  9. 4D imaging of fracturing in organic-rich shales during heating

    SciTech Connect

    Maya Kobchenko; Hamed Panahi; François Renard; Dag K. Dysthe; Anders Malthe-Sørenssen; Adriano Mazzini; Julien Scheibert1; Bjørn Jamtveit; Paul Meakin

    2011-12-01

    To better understand the mechanisms of fracture pattern development and fluid escape in low permeability rocks, we performed time-resolved in situ X-ray tomography imaging to investigate the processes that occur during the slow heating (from 60 to 400 C) of organic-rich Green River shale. At about 350 C cracks nucleated in the sample, and as the temperature continued to increase, these cracks propagated parallel to shale bedding and coalesced, thus cutting across the sample. Thermogravimetry and gas chromatography revealed that the fracturing occurring at {approx}350 C was associated with significant mass loss and release of light hydrocarbons generated by the decomposition of immature organic matter. Kerogen decomposition is thought to cause an internal pressure build up sufficient to form cracks in the shale, thus providing pathways for the outgoing hydrocarbons. We show that a 2D numerical model based on this idea qualitatively reproduces the experimentally observed dynamics of crack nucleation, growth and coalescence, as well as the irregular outlines of the cracks. Our results provide a new description of fracture pattern formation in low permeability shales.

  10. Detection of intermolecular homonuclear dipolar coupling in organic rich shale by transverse relaxation exchange

    NASA Astrophysics Data System (ADS)

    Washburn, Kathryn E.; Cheng, Yuesheng

    2017-05-01

    The mechanism behind surface relaxivity within organic porosity in shales has been an unanswered question. Here, we present results that confirm the existence of intermolecular homonuclear dipolar coupling between solid and liquid phases in sedimentary organic matter. Transverse magnetization exchange measurements were performed on an organic-rich shale saturated with liquid hydrocarbon. Liquid and solid constituents were identified through both sample resaturation and through their T1/T2 ratios. Extensive cross peaks are observed in the T2-T2 exchange spectra between the solid and liquid constituents, indicating an exchange of magnetization between the two phases. This result cannot arise from physical molecular diffusion, and the dissolution energies are too high for chemical exchange, such that the magnetization exchange must arise from intermolecular homonuclear dipolar coupling. These results both confirm a possible source of surface relaxivity in organic matter and emphasize caution in the use of standard porous media interpretations of relaxation results in shales because of coupling between different magnetization environments.

  11. The culturable bacteria isolated from organic-rich black shale potentially useful in biometallurgical procedures.

    PubMed

    Matlakowska, R; Sklodowska, A

    2009-09-01

    The aim of this study was the isolation and characterization of micro-organisms from Lubin copper mine potentially useful in biotechnology of metal recovery from copper bearing black shale. Eight bacterial strains were isolated from black shale ore. Phylogenetic analysis based on 16S rRNA gene homology showed that five strains belonged to the gamma-Proteobacteria, one to the Firmicutes and two to the Actinobacteria. The ability of the isolates to transform bituminous shale and use them as carbon and energy sources, as well as high resistance to metals and metalloids, esterase and lipase activities, assimilation of organic acids, degradation of phenanthrene and siderophores production were shown. The indigenous bacteria exhibited a broad range of physiological properties related to geochemical parameters of the examined environment and potentially useful in biometallurgical procedures. The results have yielded new insights into the microbiology of black shale. It can be suggested that isolated micro-organisms might play a role in the geochemical cycle of carbon and metals occurring in the organic fraction of black shale ore and might be of potential use in biotechnological procedures for the copper recovery and other valuable metals from tailings containing black shale as well as organic rich ore.

  12. Lysis efficiency of standard DNA extraction methods for Halococcus spp. in an organic rich environment.

    PubMed

    Leuko, S; Goh, F; Ibáñez-Peral, R; Burns, B P; Walter, M R; Neilan, B A

    2008-03-01

    The extraction of nucleic acids from a given environment marks a crucial and essential starting point in any molecular investigation. Members of Halococcus spp. are known for their rigid cell walls, and are thus difficult to lyse and could potentially be overlooked in an environment. Furthermore, the lack of a suitable lysis method hinders subsequent molecular analysis. The effects of six different DNA extraction methods were tested on Halococcus hamelinensis, Halococcus saccharolyticus and Halobacterium salinarum NRC-1 as well as on an organic rich, highly carbonated sediment from stromatolites spiked with Halococcus hamelinensis. The methods tested were based on physical disruption (boiling and freeze/thawing), chemical lysis (Triton X-100, potassium ethyl xanthogenate (XS) buffer and CTAB) and on enzymatic lysis (lysozyme). Results showed that boiling and freeze/thawing had little effect on the lysis of both Halococcus strains. Methods based on chemical lysis (Triton X-100, XS-buffer, and CTAB) showed the best results, however, Triton X-100 treatment failed to produce visible DNA fragments. Using a combination of bead beating, chemical lysis with lysozyme, and thermal shock, lysis of cells was achieved however DNA was badly sheared. Lysis of cells and DNA extraction of samples from spiked sediment proved to be difficult, with the XS-buffer method indicating the best results. This study provides an evaluation of six commonly used methods of cell lysis and DNA extraction of Halococcus spp., and the suitability of the resulting DNA for molecular analysis.

  13. Detection of intermolecular homonuclear dipolar coupling in organic rich shale by transverse relaxation exchange.

    PubMed

    Washburn, Kathryn E; Cheng, Yuesheng

    2017-03-04

    The mechanism behind surface relaxivity within organic porosity in shales has been an unanswered question. Here, we present results that confirm the existence of intermolecular homonuclear dipolar coupling between solid and liquid phases in sedimentary organic matter. Transverse magnetization exchange measurements were performed on an organic-rich shale saturated with liquid hydrocarbon. Liquid and solid constituents were identified through both sample resaturation and through their T1/T2 ratios. Extensive cross peaks are observed in the T2-T2 exchange spectra between the solid and liquid constituents, indicating an exchange of magnetization between the two phases. This result cannot arise from physical molecular diffusion, and the dissolution energies are too high for chemical exchange, such that the magnetization exchange must arise from intermolecular homonuclear dipolar coupling. These results both confirm a possible source of surface relaxivity in organic matter and emphasize caution in the use of standard porous media interpretations of relaxation results in shales because of coupling between different magnetization environments.

  14. Paleoenvironmental Controls on Early Cementation of Organic-Rich Shales in the Eagle Ford Group

    NASA Astrophysics Data System (ADS)

    Kruse, K.; Tice, M. M.

    2013-12-01

    Early carbonate cements have the potential to alter fracture toughness, and carbonate can be either promoted or inhibited by microbial processes in different redox zones. It is therefore possible that basin redox evolution could indirectly control early diagenesis and modify reservoir properties of corresponding shale units. The goals of this study are to analyze geochemical characteristics of the Late Cretaceous Eagle Ford Group in McMullen County, Texas in order to test the hypotheses that (1) the redox state of the water column controlled carbonate cement abundance and (2) carbonate cement lowered organic matter content by volumetric dilution. An X-ray analytical microscope was used to map elemental compositions of fresh core samples spanning the Eagle Ford Group. Resultant maps were used to characterize carbonate cements and to estimate the redox state of the overlying water column during deposition as proxied by the relative abundances of the trace metals Mo, V, Cr, and Zn. Preliminary results indicate that cementation occurred early relative to compaction. Ti-Kα1-normalized Mo Kα1 and Ca Kα1 fluorescence intensities are positively correlated throughout the unit, suggesting that carbonate cementation was promoted by basin euxinia. Total organic carbon is negatively correlated with (Ca Kα1)/(Ti Kα1) fluorescence ratio in the upper Eagle Ford Group, consistent with volumetric dilution of sedimentary organic matter by diagenetic cementation prior to compaction. In contrast, there is no significant correlation between total organic carbon and carbonate content in the more organic-rich lower Eagle Ford Group, suggesting that variations in organic matter production, preservation, or dilution by siliciclastic input were also important in controlling final organic content.

  15. Creep Behavior of Organic-Rich Shales - Evidences of Microscale Strain Partitioning

    NASA Astrophysics Data System (ADS)

    Sone, H.; Morales, L. F. G.; Dresen, G. H.

    2015-12-01

    Laboratory creep experiments conducted using organic-rich shales show that these rocks exhibit some ductility under sustained loading conditions although they may appear to be elastic and brittle (Young's modulus 15-80 GPa) at shorter time scales. At room-temperature and in-situ pressure conditions, creep strain observed after 3 hours of sustained loading reach strains on the order of 10-5per megapascal of applied differential stress. The creep behavior is highly anisotropic such that creep occurs more in the direction perpendicular to the bedding plane than in the direction parallel to the bedding plane. In general, we find that the creep behavior is largely controlled by the amount of clay mineral and organic content. This is also supported by evidences of elastic stiffening and sample volume reduction during creep which imply that the creep is accommodated by localized compaction occurring within clay-aggregates and/or organic materials, the relatively porous members in the rock. We also find that the tendency to creep has a unique relation with the Young's modulus regardless of the loading direction or the mineral composition. Sone and Zoback (2013) explained this correlation by appealing to the stress partitioning behavior that occurs between the relatively stiff and soft components of the rock, and also by assuming that creep only occurs within the soft components, namely the clay and organic contents, with a specific local 3-hour creep compliance value of 10-4 MPa-1. In order to confirm that such strain-partitioning occurs during creep deformation, we also performed creep experiments under a scanning electron microscope using a deformation stage setup. Such experiments allow us to directly observe the deformation and quantify the strain-partitioning occurring between the different mineral constituents with the aid of digital image correlation analysis. Results suggest that strain-partitioning do occur during creep deformation and inferred creep properties of

  16. Magnetic anisotropy of Silurian organic-rich shale rocks and calcareous concretions from Northern Poland

    NASA Astrophysics Data System (ADS)

    Niezabitowska, Dominika; Szaniawski, Rafał

    2017-04-01

    The research has been performed on Wenlockian shales of Pelplin formation from the Pomerania region located in Northern Poland. These organic-rich marine shales were deposited on the western shelf of the Baltica paleo-continent and currently they constitute the cover of East European Platform. The studied shales lie almost completely flat without signs of tectonic deformations. Rock magnetic studies were carried out with the aim of recognizing ferro- and paramagnetic minerals in shales and thus fully understanding the origin of the magnetic anisotropy. The typical dark shales and spherical calcareous concretions from two boreholes were sampled. Based on deflection of shales beds bordered with a concretions, we deduce that such concretions were formed in the early stage of diagenesis, before the final compaction and lithification of surrounding shales. We obtained similar rockmagnetic results for both of rock types. The results of thermal variation of magnetic susceptibility and hysteresis loops show that the magnetic susceptibility is mainly controlled by paramagnetic minerals, due to domination of phyllosilicate minerals, with a smaller impact of ferromagnetic phase. The results of the hysteresis studies documented the domination of low coercivity ferromagnetic minerals, that is magnetite and pyrrhotite. The deposition alignment of flocculated phyllosilicates and further compaction determine distinct bedding parallel foliation of the AMS (Anisotropy of Magnetic Susceptibility) in the both drill cores. In one of the drill core the maximal AMS axes are almost randomly distributed in the bedding plane and show only a weak tendency for grouping. In the second drill core the magnetic lineation is better defined. In the case of concretions the bedding parallel magnetic foliation is also evident but it is much weaker than in shales. In turn, the magnetic lineation in the both drill cores is well developed and the maximal AMS axes are well grouped. In both of the cores

  17. Relation between creep compliance and elastic modulus in organic-rich shales observed through laboratory experiments.

    NASA Astrophysics Data System (ADS)

    Sone, Hiroki; Zoback, Mark

    2013-04-01

    We studied the ductile creep behavior of organic-rich shales from shale gas reservoirs in North America through laboratory triaxial experiments to better understand controls on the physical behavior of these rocks over time and the effect of creep on other rock properties. Laboratory experiments conducted at room-temperature conditions show that creep deformation observed at in-situ differential stress conditions is approximately linear with the applied differential pressure. The creep behavior is also anisotropic such that creep occurs more in the bedding-perpendicular direction than in the bedding-parallel direction. The reduction in sample volume during creep suggests that the creep is accommodated by a small amount of pore compaction occurring in the clay-aggregates and/or the relatively porous kerogen in the rock. Thus, the tendency to creep (creep compliance) is generally observed to increases with clay and kerogen volume. However, the strongest correlation is found between creep compliance and Young's modulus. A strong negative correlation between creep compliance and elastic Young's modulus exists regardless of the sample orientation and despite the wide range of sample mineralogy (5-50% clay, 5-60% quartz-feldspar-pyrite, 0-80% carbonates). This correlation is quite interesting as inelastic creep and elastic stiffness depend on somewhat different physical attributes. We attempt to quantitatively explain the correlation between creep behavior and elastic stiffness by appealing to a stress-partitioning that occurs between the soft components (clay and kerogen) and stiff components (quartz, feldspar, pyrite, carbonates) of the shale rock. First, the stress-partitioning occurring within the soft and stiff components is quantified based on the rock composition, elastic properties of the individual components, and the overall average Young's modulus of the rock. By combining the stress-partitioning behavior with knowledge that the creep behavior is linear

  18. Boron isotope geochemistry during diagenesis. Part II. Applications to organic-rich sediments

    NASA Astrophysics Data System (ADS)

    Williams, Lynda B.; Hervig, Richard L.; Hutcheon, Ian

    2001-06-01

    The measured clay-water isotope fractionation for boron was applied to natural organic-rich sediments undergoing illitization. Two field areas were chosen that show illitization occurring over a range of temperatures (80-500°C). Samples representing diagenetic temperatures of illitization (80-200°C) are from the Gulf of Mexico sedimentary basin at 4 to 6-km depth in the Eocene Wilcox Fm and Jurassic Norphlet Fm. The higher temperatures of illitization (200-500°C) occur in a contact metamorphic aureole of the Cretaceous Pierre shale near Walsenburg, Colorado. Here the kinetics of the illitization reaction are more rapid than in a slowly subsiding sedimentary basin, but the chemical and mineralogical variations are minimized as complete illitization occurs over a small lateral distance in a single bentonite layer. These studies indicate that B-isotopes provide a more sensitive indicator of fluid variations in sedimentary basins than O-isotopes, and that B-isotope analyses of authigenic illite can be a valuable geochemical tracer of fluid/rock interactions. Boron isotope ratios in authigenic illite (pore filling) and muscovite (stylolites) from reservoir sandstones in the Gulf of Mexico are distinct from adjacent illitic mudstones, whereas the oxygen isotopic ratios show little variation. Fluids in equilibrium with the mudstones cannot precipitate the authigenic clays with higher δ 11B values measured in the hydrocarbon reservoirs. This suggests that the reservoir fluids were not in communication with the adjacent mudstone pore fluids but were introduced from another source area, perhaps carrying a B-isotopic label derived from the hydrocarbon source region. Authigenic illite formed in the Pierre shale meta-bentonite shows large isotopic fractionations of boron (20‰) during illitization at high temperatures. Incorporation of 500 ppm B in illite formed at 500°C shows that illite is a host for B even at metamorphic temperatures. By using the experimentally

  19. Models of Organic-Rich Surfaces in the Outer Solar System

    NASA Astrophysics Data System (ADS)

    Wilson, Peter Derrick

    This thesis applies light-scattering theory along with recently-measured optical constants of astronomically-interesting organic materials in an attempt to understand the surfaces of representative organic-rich bodies in the outer Solar System. any other object in the Solar System. The Centaur 5145 Pholus has a visible and near-ir spectrum redder than Its color can be reproduced by an intraparticle mixture of water ice, Titan tholin, and either astronomical silicate or polymerized hydrogen cyanide. The solar UV flux, combined with surface gardening by micrometeoroids, will convert all carbon-bearing ices to dark organic solids in the top millimeter of Kuiper Belt Objects in ~107 yrs. Initially red, further irradiation makes the surface more neutral. If impacts expose fresh ice over a large fraction of the object's surface on a similar time scale, an average red color may be retained. The color diversity observed in the Centaur and Kuiper Belt populations thus can be explained by a variation in the average exposure ages of their surfaces. The dark material on the leading hemisphere of Iapetus has a spectrum that is too generic, lacking in absorption features, to strongly constrain models of its composition; many mixtures of water ice, organics, and∨ silicates can reproduce its albedo and spectrum. Several mechanisms have been proposed to explain why one hemisphere of Iapetus is extremely dark while the other hemisphere is very bright, but this thesis finds major flaws in most of them. A scheme postulating a global, several-km-thick layer of dark material covered by a layer of ice ~1-m thick, but which is excavated on the leading hemisphere, works best. Finally, the impacts of the fragments of Comet Shoemaker-Levy 9 into Jupiter left behind dark atmospheric blemishes that may be composed of organic matter. The optical constants of the blemish aerosols-as derived by others-are near-perfect matches to Murchison organic residue. The reflectances of the initial impact

  20. Sulfur and oxygen isotope geochemistry of acid mine drainage--the polymetallic sulfide deposit "himmelfahrt fundgrube" in Freiberg (Germany).

    PubMed

    Haubrich, F; Tichomirowa, M

    2002-06-01

    We investigated physical, chemical and isotope (S, O) parameters of sulfate from acid mine drainage from the polymetallic sulfide ore deposit Freiberg (Gennany), which was mined for more than eight hundred years. Two main groups of water were distinguished: 1. Flowing mine water with sulfate concentrations of less than 9,000 mg/l and pH values higher than 3.2, 2. Pore water in weathered low grade ores and pools with sulfate concentrations higher than 9000mg/l and pH values below 3.2. The sulfur and oxygen isotope composition of sulfate from flowing mine waters reflects mixing of sulfate from two sulfur sources: a) atmospheric sulfur from precipitation and b) sulfate formed as a result of sulfide oxidation processes. Sulfur isotope values of mine water sulfate were used to estimate the contribution of sulfate derived through oxidation of sulfides. The sulfur isotope composition of pore water sulfate and precipitated sulfate (jarosite) from weathered low grade ore samples is identical to the sulfur isotope composition of primary sulfides. The oxygen isotope composition of pore water sulfate from low grade ore samples indicates that the oxidation process proceeds relatively slowly in 02-depleted waters, probably without significant microbial catalysis.

  1. Arctic catchment releases mostly young aquatic carbon despite complete thawing of old organic-rich permafrost soils during growing season.

    NASA Astrophysics Data System (ADS)

    Dean, Joshua F.; Billett, Michael F.; Dinsmore, Kerry J.; Garnett, Mark H.; van der Velde, Ype

    2017-04-01

    Radiocarbon (14C) dating of dissolved organic carbon (DOC) in Arctic freshwaters has been used as a crucial tool for detecting old C mobilised from thawing permafrost, but DO14C in major Arctic rivers is usually quite young. New methods for the collection of both CO2 and CH4 from inland waters allow novel observation of dissolved 14CO2 and 14CH4 alongside DO14C, and provide a more sensitive method than aquatic OC alone - published Arctic freshwater 14C studies to date focus only on DOC, particulate OC, or ebullition CH4/CO2. The mobilisation of old C sourced from deepening permafrost soil active-layers into Arctic freshwaters has the potential to form a significant positive climate feedback. We compare 14C in DOC, dissolved CO2 and dissolved CH4 at five time points over a single growing season from streams, ponds and lakes underlain by continuous permafrost in the western Canadian Arctic. Using age distribution analysis based on atmospheric 14CO2 records, we estimated the age of aquatic C that would otherwise be labelled as "modern" due to the 14C bomb peak. We then calculated the vertical and lateral C fluxes in the study systems, and estimated the proportion derived from old permafrost C. The upper organic-rich soils are the dominant hydrologic pathway, which were completely thawed by late season, and we hypothesised that mobilisation of older, deeper organic soil C would be visible in the aquatic 14C by late in the growing season. Early in the season, median aquatic DO14C and CO2 ages were 65-131 years old (all 14C ages reported here are years before sampling date). By the end of the season, DO14C was 156-271 years old, while CO2 was 113-161 years old, demonstrating that aquatic C ages reflect the mobilisation of thawing older permafrost C. CH4 concentrations were generally low throughout and only two dates were obtained: 202 and 1,970 years old. Overall there was limited evidence of very old permafrost organic C, which comprised 0-10% of vertical and lateral

  2. Controls on composition and distribution of lacustrine organic-rich rocks of the Green River fm. , Wyoming

    SciTech Connect

    Grabowski, G.J. Jr. ); Bohacs, K.M. )

    1996-01-01

    Lake type controls the accumulation of organic-rich rocks, climate and hydrology determine lake type, The amount and composition of organic matter, and the thickness, variability and lateral extent of organic-rich rocks, differ in freshwater, alkaline and saline take deposits, as illustrated by the Eocene Green River Fm. The Luman Tongue was deposited in freshwater, thermally stratified lakes. It consists of sequences of lacustrine shales, 100's of feet thick, that are variable in composition. Littoral coals and shales with less than 2% TOC are composed of Type-III kerogen (HI 58-300 mg/gC). Profundal shales have up to 7% TOC that is a mixture of Types I and III kerogen (HI <580). Low TOC values are due to poor preservation in the lake sediments and dilution by detrital deposition. Input of land- derived organic matter causes much variability in organic-matter type. The Laney Member was deposited in alkaline, chemically stratified lakes with littoral marshes. Well-defined sequences 10-20 ft. thick characterize this member. Littoral shales have less than 7% TOC that is a mixture of Types I and III kerogen (HI 235-650). Profundal dolomitic lime mudstones have up to 30% TOC enriched in Type I kerogen (HI 500-650). TOC and HI values are typically highest near the base of each sequence, where the lake was at its maximum extent, deposition from land was restricted to littoral areas, and the bottom sediments were depleted in oxygen. The Wilkins Peak Member was deposited in saline, chemically stratified playa lakes. Organic-rich rocks 1-5 ft. thick occur at the bases of several sequences that are 3-10 ft. thick. These organic-rich dolomitic lime mudstones have 5-20% TOC composed of Type-I kerogen (HI 650-1100). TOC and HI values vary little laterally, reflecting an absence of diluting sedimentation or input of organic matter from land.

  3. Controls on composition and distribution of lacustrine organic-rich rocks of the Green River fm., Wyoming

    SciTech Connect

    Grabowski, G.J. Jr.; Bohacs, K.M.

    1996-12-31

    Lake type controls the accumulation of organic-rich rocks, climate and hydrology determine lake type, The amount and composition of organic matter, and the thickness, variability and lateral extent of organic-rich rocks, differ in freshwater, alkaline and saline take deposits, as illustrated by the Eocene Green River Fm. The Luman Tongue was deposited in freshwater, thermally stratified lakes. It consists of sequences of lacustrine shales, 100`s of feet thick, that are variable in composition. Littoral coals and shales with less than 2% TOC are composed of Type-III kerogen (HI 58-300 mg/gC). Profundal shales have up to 7% TOC that is a mixture of Types I and III kerogen (HI <580). Low TOC values are due to poor preservation in the lake sediments and dilution by detrital deposition. Input of land- derived organic matter causes much variability in organic-matter type. The Laney Member was deposited in alkaline, chemically stratified lakes with littoral marshes. Well-defined sequences 10-20 ft. thick characterize this member. Littoral shales have less than 7% TOC that is a mixture of Types I and III kerogen (HI 235-650). Profundal dolomitic lime mudstones have up to 30% TOC enriched in Type I kerogen (HI 500-650). TOC and HI values are typically highest near the base of each sequence, where the lake was at its maximum extent, deposition from land was restricted to littoral areas, and the bottom sediments were depleted in oxygen. The Wilkins Peak Member was deposited in saline, chemically stratified playa lakes. Organic-rich rocks 1-5 ft. thick occur at the bases of several sequences that are 3-10 ft. thick. These organic-rich dolomitic lime mudstones have 5-20% TOC composed of Type-I kerogen (HI 650-1100). TOC and HI values vary little laterally, reflecting an absence of diluting sedimentation or input of organic matter from land.

  4. Chemical analysis of extracting transition metal oxides from polymetallic ore by sulphate process

    NASA Astrophysics Data System (ADS)

    Enkh-Uyanga, Otgon-Uul; Munkhtsetseg, Baatar; Urangoo, Urtnasan; Tserendulam, Enkhtur; Agiimaa, Davaadorj

    2017-06-01

    In this research work we attempt to improve the purity of polymetallic ores in Mongolia whilst developing practical applications of its refinement processes and this paper presents the results of chemical research of extracting transition metal titanium oxides, ferrous oxide and rare earth oxides from polymetallic ore. Thereby, chemical and mineral analysis of polymetallic ore is carried out basis of responses to the support process at various degrees of water whereas transition metal sulphates solubility differ. As a result of sulphate and resulphurization process we have extracted anatase with 62.5 percent titanium dioxide and brookite mineral with 89.6 percent of titanium dioxide as well as mineral with 83.8 percent of ferrous oxide hematite and rare earth oxides with 57.6 percent of cerium oxide. These oxides are identified under various conditions in the thermal processing. The morphology structure and chemical content compound of the mineral has been verified as a result of the XRF, XRD, SEM-EDX analysis.

  5. Critical elements in sediment-hosted deposits (clastic-dominated Zn-Pb-Ag, Mississippi Valley-type Zn-Pb, sedimentary rock-hosted Stratiform Cu, and carbonate-hosted Polymetallic Deposits): A review: Chapter 12

    USGS Publications Warehouse

    Marsh, Erin; Hitzman, Murray W.; Leach, David L.

    2016-01-01

    Some sediment-hosted base metal deposits, specifically the clastic-dominated (CD) Zn-Pb deposits, carbonate-hosted Mississippi Valley-type (MVT) deposits, sedimentary-rock hosted stratiform copper deposits, and carbonate-hosted polymetallic (“Kipushi type”) deposits, are or have been important sources of critical elements including Co, Ga, Ge, and Re. The generally poor data concerning trace element concentrations in these types of sediment-hosted ores suggest that there may be economically important concentrations of critical elements yet to be recognized.

  6. Integrated bio-chemostratigraphy of Late Cretaceous organic-rich marine sediments in Israel

    NASA Astrophysics Data System (ADS)

    Mizrahi, Nitzan; Harlavan, Yehudit; Abramovich, Sigal; Ashckenazi-Polivoda, Sarit

    2017-04-01

    The Late Cretaceous was a time of great climatic and paleocanographic changes that had major impact on the global marine ecosystems. The timing of these events must be accurately determined based on a reliable chronostratigraphic framework that can be readily applied in various environmental settings. The Late Cretaceous planktic foraminiferal biostratigraphic zonation is mainly based on tropical-subtropical species that are typically found in normal pelagic settings. However, during this time, unique conditions of high water column productivity and oxygen deficiency prevailed throughout the Levant region, including Israel, causing a partial to total exclusion of some of these species. Consequently, establishing age framework based on biostratigraphic correlation of the Levant region is a challenging task, emphasizing the need to apply additional method to advance the regional chronostratigraphy. Among these, is chemostratigraphy based on the 87Sr/86Sr ratio in of the carbonate tests of foraminifera, which is now widely used for stratigraphic correlation. The main objective of the present research was to improve the chronostratigraphic resolution for the Upper Cretaceous organic-rich sequence in Israel. This was accomplished by integrating detailed correlation of planktic and benthic foraminiferal bioevents, with 87Sr/86Sr ratio, correlated to the global 87Sr/86Sr ratio curve. This integration provides a new and much improved chronostratigraphic framework of the Late Cretaceous strata of Israel and the entire Levant region. It allows to integrate sections with poorly preserved or lack of the common biomarkers, define for the biozone. In general this should yield the best age control for economically valuable stratigraphic units (e.g., oil shale) deposited during this time. The biozonation of the studied sections, RE-2 and RE-6 from the Negev basins (southern Israel), spans from the Late Santonian Dicarinella asymetrica Zone to the middle Maastrichtian Abathomphalus

  7. A tectonic model for the spatial occurrence of porphyry copper and polymetallic vein deposits - applications to Central Europe

    USGS Publications Warehouse

    Drew, Lawrence J.

    2006-01-01

    A structural-tectonic model, which was developed to assess the occurrence of undiscovered porphyry copper deposits and associated polymetallic vein systems for the Matra Mountains, Hungary, has been expanded here and applied to other parts of central Europe. The model explains how granitoid stocks are emplaced and hydrothermal fluids flow within local strain features (duplexes) within strike-slip fault systems that develop in continental crust above subducting plates. Areas of extension that lack shear at the corners and along the edges of the fault duplexes are structural traps for the granitoid stocks associated with porphyry copper deposits. By contrast, polymetallic vein deposits are emplaced where shear and extension are prevalent in the interior of the duplexes. This model was applied to the Late Cretaceous-age porphyry copper and polymetallic vein deposits in the Banat-Timok-Srednogorie region of Romania-Serbia-Bulgaria and the middle Miocene-age deposits in Romania and Slovakia. In the first area, porphyry copper deposits are most commonly located at the corners, and occasionally along the edges, of strike-slip fault duplexes, and the few polymetallic vein deposits identified are located at interior sites of the duplexes. In the second area, the model accounts for the preferred sites of porphyry copper and polymetallic vein deposits in the Apuseni Mountains (Romania) and central Slovakian volcanic field (Slovakia).

  8. Comparison of fluid geochemistry and microbiology of multiple organic-rich reservoirs in the Illinois Basin, USA: Evidence for controls on methanogenesis and microbial transport

    NASA Astrophysics Data System (ADS)

    Schlegel, Melissa E.; McIntosh, Jennifer C.; Bates, Brittney L.; Kirk, Matthew F.; Martini, Anna M.

    2011-04-01

    Microbial methane in sedimentary basins comprises approximately 20% of global natural gas resources, yet little is known about the environmental requirements and metabolic rates of these subsurface microbial communities. The Illinois Basin, located in the midcontinent of the United States, is an ideal location to investigate hydrogeochemical factors controlling methanogenesis as microbial methane accumulations occur: (1) in three organic-rich reservoirs of different geologic ages and organic matter types - Upper Devonian New Albany Shale (up to 900 m depth), Pennsylvanian coals (up to 600 m depth), and Quaternary glacial sediments (shallow aquifers); (2) across steep salinity gradients; and (3) with variable concentrations of SO42-. For all three organic-rich reservoirs aqueous geochemical conditions are favorable for microbial methanogenesis, with near neutral pH, SO42- concentrations <2 mM, and Cl - concentrations <3 M. Also, carbon isotopic fractionation of CH 4, CO 2, and DIC is consistent with microbial methanogenesis, and increased carbon isotopic fractionation with average reservoir depth corresponds to a decrease of groundwater flushing rates with average depth of reservoir. Plots of stable isotopes of water and Cl - show mixing between a brine endmember and freshwater, suggesting that meteoric groundwater recharge has affected all microbial methanogenic systems. Additionally, similar methanogenic communities are present in all three reservoirs with comparable cell counts (8.69E3-2.58E6 cells/mL). TRFLP results show low numbers of archaea species with only two dominant groups of base pairs in coals, shale, and limestone aquifers. These results compare favorably with other methanogen-containing deep subsurface environments. Individual hydrogeochemical parameters that have a Spearman correlation coefficient greater than 0.3 to variations in methanogenic species include stable isotopes of water (δ 18O and δD), type of substrate (i.e. coals versus shale), p

  9. Effect of organic matter properties, clay mineral type and thermal maturity on gas adsorption in organic-rich shale systems

    USGS Publications Warehouse

    Zhang, Tongwei; Ellis, Geoffrey S.; Ruppel, Stephen C.; Milliken, Kitty; Lewan, Mike; Sun, Xun; Baez, Luis; Beeney, Ken; Sonnenberg, Steve

    2013-01-01

    A series of CH4 adsorption experiments on natural organic-rich shales, isolated kerogen, clay-rich rocks, and artificially matured Woodford Shale samples were conducted under dry conditions. Our results indicate that physisorption is a dominant process for CH4 sorption, both on organic-rich shales and clay minerals. The Brunauer–Emmett–Teller (BET) surface area of the investigated samples is linearly correlated with the CH4 sorption capacity in both organic-rich shales and clay-rich rocks. The presence of organic matter is a primary control on gas adsorption in shale-gas systems, and the gas-sorption capacity is determined by total organic carbon (TOC) content, organic-matter type, and thermal maturity. A large number of nanopores, in the 2–50 nm size range, were created during organic-matter thermal decomposition, and they significantly contributed to the surface area. Consequently, methane-sorption capacity increases with increasing thermal maturity due to the presence of nanopores produced during organic-matter decomposition. Furthermore, CH4 sorption on clay minerals is mainly controlled by the type of clay mineral present. In terms of relative CH4 sorption capacity: montmorillonite ≫ illite – smectite mixed layer > kaolinite > chlorite > illite. The effect of rock properties (organic matter content, type, maturity, and clay minerals) on CH4 adsorption can be quantified with the heat of adsorption and the standard entropy, which are determined from adsorption isotherms at different temperatures. For clay-mineral rich rocks, the heat of adsorption (q) ranges from 9.4 to 16.6 kJ/mol. These values are considerably smaller than those for CH4 adsorption on kerogen (21.9–28 kJ/mol) and organic-rich shales (15.1–18.4 kJ/mol). The standard entropy (Δs°) ranges from -64.8 to -79.5 J/mol/K for clay minerals, -68.1 to -111.3 J/mol/K for kerogen, and -76.0 to -84.6 J/mol/K for organic-rich shales. The affinity of CH4 molecules for sorption on organic matter

  10. Biological responses to disturbance from simulated deep-sea polymetallic nodule mining

    PubMed Central

    Kaiser, Stefanie; Sweetman, Andrew K.; Smith, Craig R.; Menot, Lenaick; Vink, Annemiek; Trueblood, Dwight; Greinert, Jens; Billett, David S. M.; Arbizu, Pedro Martinez; Radziejewska, Teresa; Singh, Ravail; Ingole, Baban; Stratmann, Tanja; Simon-Lledó, Erik; Durden, Jennifer M.; Clark, Malcolm R.

    2017-01-01

    Commercial-scale mining for polymetallic nodules could have a major impact on the deep-sea environment, but the effects of these mining activities on deep-sea ecosystems are very poorly known. The first commercial test mining for polymetallic nodules was carried out in 1970. Since then a number of small-scale commercial test mining or scientific disturbance studies have been carried out. Here we evaluate changes in faunal densities and diversity of benthic communities measured in response to these 11 simulated or test nodule mining disturbances using meta-analysis techniques. We find that impacts are often severe immediately after mining, with major negative changes in density and diversity of most groups occurring. However, in some cases, the mobile fauna and small-sized fauna experienced less negative impacts over the longer term. At seven sites in the Pacific, multiple surveys assessed recovery in fauna over periods of up to 26 years. Almost all studies show some recovery in faunal density and diversity for meiofauna and mobile megafauna, often within one year. However, very few faunal groups return to baseline or control conditions after two decades. The effects of polymetallic nodule mining are likely to be long term. Our analyses show considerable negative biological effects of seafloor nodule mining, even at the small scale of test mining experiments, although there is variation in sensitivity amongst organisms of different sizes and functional groups, which have important implications for ecosystem responses. Unfortunately, many past studies have limitations that reduce their effectiveness in determining responses. We provide recommendations to improve future mining impact test studies. Further research to assess the effects of test-mining activities will inform ways to improve mining practices and guide effective environmental management of mining activities. PMID:28178346

  11. Biological responses to disturbance from simulated deep-sea polymetallic nodule mining.

    PubMed

    Jones, Daniel O B; Kaiser, Stefanie; Sweetman, Andrew K; Smith, Craig R; Menot, Lenaick; Vink, Annemiek; Trueblood, Dwight; Greinert, Jens; Billett, David S M; Arbizu, Pedro Martinez; Radziejewska, Teresa; Singh, Ravail; Ingole, Baban; Stratmann, Tanja; Simon-Lledó, Erik; Durden, Jennifer M; Clark, Malcolm R

    2017-01-01

    Commercial-scale mining for polymetallic nodules could have a major impact on the deep-sea environment, but the effects of these mining activities on deep-sea ecosystems are very poorly known. The first commercial test mining for polymetallic nodules was carried out in 1970. Since then a number of small-scale commercial test mining or scientific disturbance studies have been carried out. Here we evaluate changes in faunal densities and diversity of benthic communities measured in response to these 11 simulated or test nodule mining disturbances using meta-analysis techniques. We find that impacts are often severe immediately after mining, with major negative changes in density and diversity of most groups occurring. However, in some cases, the mobile fauna and small-sized fauna experienced less negative impacts over the longer term. At seven sites in the Pacific, multiple surveys assessed recovery in fauna over periods of up to 26 years. Almost all studies show some recovery in faunal density and diversity for meiofauna and mobile megafauna, often within one year. However, very few faunal groups return to baseline or control conditions after two decades. The effects of polymetallic nodule mining are likely to be long term. Our analyses show considerable negative biological effects of seafloor nodule mining, even at the small scale of test mining experiments, although there is variation in sensitivity amongst organisms of different sizes and functional groups, which have important implications for ecosystem responses. Unfortunately, many past studies have limitations that reduce their effectiveness in determining responses. We provide recommendations to improve future mining impact test studies. Further research to assess the effects of test-mining activities will inform ways to improve mining practices and guide effective environmental management of mining activities.

  12. The application of soft X-ray microscopy to the in-situ analysis of sporopollenin/sporinite in a rank variable suite of organic rich sediments

    SciTech Connect

    Cody, G.D.; Botto, R.E.; Ade, H.; Wirick, S.

    1997-07-01

    Soft X-ray imaging and carbon near edge absorption fine structure spectroscopy (C-NEXAFS) has been used for the in-situ analysis of sporinite in a rank variable suite of organic rich sediments extending from recent up to high volatile A bituminous coal. The acquisition of chemically based images (contrast based on the 1s - 1{pi}* transition of unsaturated carbon), revealed a homogeneous chemical structure in the spore exine. C-NEXAFS microanalysis indicates chemical structural evolution in sporopollenin/sporinite with increases in maturation. The most significant change in the C-NEXAFS spectrum is an increase in unsaturated carbon, presumably aromatic, with rank. The rate of aromatization in sporinite exceeds that of the surrounding vitrinite. Increases in the concentration of unsaturated carbon are compensated by losses of aliphatic and hydroxylated aliphatic carbon components. Carboxyl groups are present in low and variable concentrations. Absorption due to carboxyl persists in the most mature specimen in this series, a high volatile A rank coal. The reactions which drive sporopollenin chemical structural evolution during diagenesis presumably involve dehydration, Diels-Alder cyclo-addition, and dehydrogenation reactions which ultimately lead to a progressively aromatized bio/geopolymer.

  13. A kuroko-type polymetallic sulfide deposit in a submarine silicic caldera

    PubMed

    Iizasa; Fiske; Ishizuka; Yuasa; Hashimoto; Ishibashi; Naka; Horii; Fujiwara; Imai; Koyama

    1999-02-12

    Manned submersible studies have delineated a large and actively growing Kuroko-type volcanogenic massive sulfide deposit 400 kilometers south of Tokyo in Myojin Knoll submarine caldera. The sulfide body is located on the caldera floor at a depth of 1210 to 1360 meters, has an area of 400 by 400 by 30 meters, and is notably rich in gold and silver. The discovery of a large Kuroko-type polymetallic sulfide deposit in this arc-front caldera raises the possibility that the numerous unexplored submarine silicic calderas elsewhere might have similar deposits.

  14. Geochemical and biostratigraphic characterization of an upper Cretaceous organic-rich condensed section in the Santos Basin, Brazil

    SciTech Connect

    Trindade, L.A.F., Porsche, E.; Penteado, H.L.B. )

    1996-01-01

    The Cenomanian-Turonian section is worldwide recognized as an organic- rich interval associated with a widespread anoxic event. Samples from this interval, representing proximal sedimentary conditions have been well characterized in the Santos Basin, Brazil, where it reaches 300m thickness. The main objective of this study is to characterize the geochemical and paleoecological attributes as well as to ascertain the biostratigraphic position of this organic-rich section in a more distal location, at ODP Site 356. Biostratigraphic analyses identify die interval at ODP Site 356 as a condensed section ranging in age from Cenomanian to Coniacian (11 m), deposited under anoxic conditions associated with a warm, and climate in the adjacent continental areas. Geochemical analyses indicate high total organic carbon contents (up tp 6.7%), dominance of algal derived material, high relative abundances of homohopanes and methylsteranes, [delta][sup 13]C around -27[per thousand], indicating a typical marine anoxic section. Despite the high content of oil-prone organic matter, this section has not attained thermal evolution appropriated for hydrocarbon generation due to its shallow burial. In proximal areas of the basin, this section is interpreted as a transgressive system tract which is composed by a series of sequences, that are enriched in organic material at their bases. Basinward the interval is thinner, but presents higher organic carbon contents according to geochemical data of ODP Site 356, typical of a condensed section.

  15. Geochemical and biostratigraphic characterization of an upper Cretaceous organic-rich condensed section in the Santos Basin, Brazil

    SciTech Connect

    Trindade, L.A.F., Porsche, E.; Penteado, H.L.B.

    1996-12-31

    The Cenomanian-Turonian section is worldwide recognized as an organic- rich interval associated with a widespread anoxic event. Samples from this interval, representing proximal sedimentary conditions have been well characterized in the Santos Basin, Brazil, where it reaches 300m thickness. The main objective of this study is to characterize the geochemical and paleoecological attributes as well as to ascertain the biostratigraphic position of this organic-rich section in a more distal location, at ODP Site 356. Biostratigraphic analyses identify die interval at ODP Site 356 as a condensed section ranging in age from Cenomanian to Coniacian (11 m), deposited under anoxic conditions associated with a warm, and climate in the adjacent continental areas. Geochemical analyses indicate high total organic carbon contents (up tp 6.7%), dominance of algal derived material, high relative abundances of homohopanes and methylsteranes, {delta}{sup 13}C around -27{per_thousand}, indicating a typical marine anoxic section. Despite the high content of oil-prone organic matter, this section has not attained thermal evolution appropriated for hydrocarbon generation due to its shallow burial. In proximal areas of the basin, this section is interpreted as a transgressive system tract which is composed by a series of sequences, that are enriched in organic material at their bases. Basinward the interval is thinner, but presents higher organic carbon contents according to geochemical data of ODP Site 356, typical of a condensed section.

  16. Biotransformation of organic-rich copper-bearing black shale by indigenous microorganisms isolated from lubin copper mine (Poland).

    PubMed

    Matlakowska, Renata; Narkiewicz, Wanda; Sklodowska, Aleksandra

    2010-04-01

    The role of indigenous microorganisms in the biotransformation of refractory organic-rich copper-bearing black shale ore (Kupferschiefer) was confirmed in laboratory experiments. The persistent shale's organic matter was utilized by a mixture of bacterial strains as the sole carbon and energy source, and bacterial growth was accompanied by chemical and structural changes of black shale. The release of metallic elements and organic compounds into the aqueous phase was shown. Chemical analysis revealed the presence of long-chain aliphatic hydrocarbons and further biodegradation of these compounds by bacterial action. In this study, the release of metals from metalloorganic compounds present in organic-rich copper-bearing black shale was shown for the first time. The results have also confirmed the biotransformation of metalloporphyrins naturally occurring in black shale by indigenous microorganisms. Moreover, changes in the surface area and quantitative mineral composition of black shale were detected following bacterial treatment. This biotransformation activity is of potential use in biotechnological procedures for the recovery of copper and other valuable metals from tailings that contain up to 16% black shale. On the other hand, the release of organic carbon and heavy metals from black shale by biodegradation may significantly add to anthropogenic pollution.

  17. Contrasted responses of Ruditapes decussatus (filter and deposit feeding) and Loripes lacteus (symbiotic) exposed to polymetallic contamination (Port-Camargue, France).

    PubMed

    Caro, Audrey; Chereau, Gaetan; Briant, Nicolas; Roques, Cécile; Freydier, Rémi; Delpoux, Sophie; Escalas, Arthur; Elbaz-Poulichet, Françoise

    2015-02-01

    The use of symbiotic bivalve species to assess the effect of anthropogenic metal pollution was rarely investigated whereas data on filter feeding bivalves are common. The aim of this study was the exposure of two bivalve species, Ruditapes decussatus and Loripes lacteus to polymetallic pollution gradient, originating from harbor activities (Port-Camargue, south of France). Both bivalves differ by their trophic status, filter and deposit feeder for Ruditapes and symbiotic for Loripes that underlies potential differences in metal sensibility. The bivalves were immerged in July (for Ruditapes during 2 and 8 days) and in August 2012 (for Loripes during 2, 6 and 8 days) in the water column of the harbor, at 3 stations according to pollution gradient. Metal concentrations (Cu, Mn, Zn) in the water column were quantified as dissolved metals (measured by ICP-MS) and as labile metals (measured by ICP-MS using DGT technique). For each exposure time, accumulation of metals in the soft tissue of bivalves ("bioaccumulation") was measured for both species. In addition, specific parameters, according to the trophic status of each bivalve, were investigated: filtering activity (specific clearance rate, SCR) for Ruditapes, and relative cell size (SSC) and genomic content (FL1) of bacterial symbionts hosted in the gills of Loripes. The SCR of Ruditapes drops from 100% (control) to 34.7% after 2 days of exposure in the less contaminated site (station 8). On the other hand, the relative cell size (SSC) and genomic content (FL1), measured by flow cytometry were not impacted by the pollution gradient. Bioaccumulation was compared for both species, showing a greater capability of Cu accumulation for Loripes without lethal effect. Mn, Fe and Zn were generally not accumulated by any of the species according to the pollution gradient. The trophic status of each species may greatly influence their respective responses to polymetallic pollution.

  18. Early gene expression in Pseudomonas fluorescens exposed to a polymetallic solution.

    PubMed

    Gómez-Sagasti, María T; Becerril, José M; Epelde, Lur; Alkorta, Itziar; Garbisu, Carlos

    2015-02-01

    The molecular response of Pseudomonas fluorescens cells exposed to a mixture of heavy metals remains largely unknown. Here, we studied the temporal changes in the early gene expression of P. fluorescens cells exposed to three doses of a polymetallic solution over two exposure times, through the application of a customized cDNA microarray. At the lowest metal dose (MD/4), we observed a repression of the Hsp70 chaperone system, MATE and MFS transporters, TonB membrane transporter and histidine kinases, together with an overexpression of metal transport (ChaC, CopC), chemotaxis and glutamine synthetase genes. At the intermediate metal dose (MD), several amino acid transporters, a response regulator (CheY), a TonB-dependent receptor and the mutT DNA repair gene were repressed; by contrast, an overexpression of genes associated with the antioxidative stress system and the transport of chelates and sulfur was observed. Finally, at the highest metal dose (4MD), a repression of genes encoding metal ion transporters, drug resistance and alginate biosynthesis was found, together with an overexpression of genes encoding antioxidative proteins, membrane transporters, ribosomal proteins, chaperones and proteases. It was concluded that P. fluorescens cells showed, over exposure time, a highly complex molecular response when exposed to a polymetallic solution, involving mechanisms related with chemotaxis, signal transmission, membrane transport, cellular redox state, and the regulation of transcription and ribosomal activity.

  19. Biosourced polymetallic catalysts: an efficient means to synthesize underexploited platform molecules from carbohydrates.

    PubMed

    Escande, Vincent; Olszewski, Tomasz K; Petit, Eddy; Grison, Claude

    2014-07-01

    Polymetallic hyperaccumulating plants growing on wastes from former mining activity were used as the starting material in the preparation of novel plant-based Lewis acid catalysts. The preparation of biosourced Lewis acid catalysts is a new way to make use of mining wastes. These catalysts were characterized by X-ray fluorescence, X-ray diffraction, inductively coupled plasma mass spectrometry, and direct infusion electrospray ionization mass spectrometry. These analyses revealed a complex composition of metal species, present mainly as polymetallic chlorides. The catalysts proved to be efficient and recyclable in a solid-state version of the Garcia Gonzalez reaction, which has been underexploited until now in efforts to use carbohydrates from biomass. This methodology was extended to various carbohydrates to obtain the corresponding polyhydroxyalkyl furans in 38-98% yield. These plant-based catalysts may be a better alternative to classical Lewis acid catalysts that were previously used for the Garcia Gonzalez reaction, such as ZnCl2 , FeCl3 , and CeCl3 , which are often unrecyclable, require aqueous treatments, or rely on metals, the current known reserves of which will be consumed in the coming decades. Moreover, the plant-based catalysts allowed novel control of the Garcia Gonzalez reaction, as two different products were obtained depending on the reaction conditions.

  20. I/TOC in organic-rich shale as a potential tool to gauge iodine burial during the Oceanic Anoxic Events (OAEs)

    NASA Astrophysics Data System (ADS)

    Zhou, X.; Lu, Z.

    2013-12-01

    OAEs were likely triggered by volcanic activity and warming, causing increased continental weathering and circulation changes, which further stimulated productivity and CO2 drawdown through nutrient cycle feedbacks, eventually leading to significant ocean deoxygenation. I/Ca ratios in bulk carbonates were used to reconstruct relatively subtle redox changes in surface waters, since the oxidized form of iodine (iodate) can be incorporated in carbonate. Lower I/Ca ratios were found during the OAE interval, interpreted to be the result of both iodate reduction and iodine drawdown by increased organic carbon burial. Organic matter burial is the largest sink of iodine in modern ocean. It is important to reconstruct iodine burial during the OAE, in order to better interpret the I/Ca record. We aim to develop a new method for measuring iodine concentration in organic-rich shale with small sample size < 50mg, making high resolution work possible for future studies. Preliminary data indicate I/TOC ratio might have been significantly lower during the OAE compared to background levels. The iodine drawdown from seawater could be much smaller than intuitively assumed for such organic carbon burial events.

  1. Microbial colonization and degradation of polyethylene and biodegradable plastic bags in temperate fine-grained organic-rich marine sediments.

    PubMed

    Nauendorf, Alice; Krause, Stefan; Bigalke, Nikolaus K; Gorb, Elena V; Gorb, Stanislav N; Haeckel, Matthias; Wahl, Martin; Treude, Tina

    2016-02-15

    To date, the longevity of plastic litter at the sea floor is poorly constrained. The present study compares colonization and biodegradation of plastic bags by aerobic and anaerobic benthic microbes in temperate fine-grained organic-rich marine sediments. Samples of polyethylene and biodegradable plastic carrier bags were incubated in natural oxic and anoxic sediments from Eckernförde Bay (Western Baltic Sea) for 98 days. Analyses included (1) microbial colonization rates on the bags, (2) examination of the surface structure, wettability, and chemistry, and (3) mass loss of the samples during incubation. On average, biodegradable plastic bags were colonized five times higher by aerobic and eight times higher by anaerobic microbes than polyethylene bags. Both types of bags showed no sign of biodegradation during this study. Therefore, marine sediment in temperate coastal zones may represent a long-term sink for plastic litter and also supposedly compostable material.

  2. Evolution of organo-clay composites with respect to thermal maturity in type II organic-rich source rocks

    NASA Astrophysics Data System (ADS)

    Berthonneau, Jeremie; Grauby, Olivier; Abuhaikal, Muhannad; Pellenq, Roland J.-M.; Ulm, Franz J.; Van Damme, Henri

    2016-12-01

    Among the proposed pathways of sequestration and progressive transformation of organic matter (OM) during burial, the sorptive protection mechanism explains the strong relationship between total organic carbon (TOC) and mineral surface area (MSA) noted in numerous black shales around the globe. The complete mechanistic framework of preservation and evolution of OM in organo-mineral complexes remains, however, an enigma. On one hand, smectite layers composing the clay fraction are known to have a major influence on available surface area. OM maturation occurs, on the other hand, concurrently with the smectite illitization that provokes the closure of the interlayer spaces. The potential of smectite layers in the sequestration and preservation of organic molecules and the fate of these molecules with respect to the smectite illitization were therefore addressed. Here, the mineralogy of three organic-rich source rocks of various maturities was characterized in regards with the geochemistry of their OM. A thorough examination of the clay minerals present in the clay matrices provided evidences of mixed layer minerals containing smectite and illite layers with an increasing illite component with respect to maturity. The comprehensive interpretation of the X-ray diffractograms and analytical electron microscopy results suggested the presence of organic molecules in the inter-particulate and possibly the interlayer spaces of the smectite-rich components in immature source rocks. This eventuality was further supported by the presence of intercalated clay-organic nanocomposites observed by transmitted electron microscopy coupled with energy dispersive spectroscopy. Textural observations also showed that the increased illite content found in the overmature sample led to the reorganization of the OM and the clay particles into nano-scale aggregates. These results clarify the geochemical mechanism beyond the reported relationship between TOC and MSA and allow generalizing it

  3. Function of a deltaic silt deposit as a repository and long-term source of sulfate and related weathering products in a glaciofluvial aquifer derived from organic-rich shale (North Dakota, USA)

    NASA Astrophysics Data System (ADS)

    Schuh, W. M.; Bottrell, S. H.

    2014-05-01

    A shallow unconfined glaciofluvial aquifer in North Dakota (USA) has largest groundwater sulfate concentrations near the bottom boundary. A deltaic silt layer underlying the aquifer, at >16 m, is the modern proximate sulfate source for the aquifer. The original sulfate source was pyrite in the organic-rich shale component of the aquifer and silt grain matrix. An oxidizing event occurred during which grain-matrix pyrite sulfur was oxidized to sulfate. Thereafter the silt served as a "conserving" layer, slowly feeding sulfate into the lower part of the aquifer and the underlying till. A method was developed for estimating the approximate initial sulfate concentration in the source layer and the redistribution time since the oxidizing event, using a semi-generic convection-dispersion model. The convection-dispersion model and a model for the evolution of modern sulfate δ 34S in silt-layer pore water from the initial grain-matrix pyrite δ 34S, both estimated that the oxidizing event occurred several thousand years ago, and was likely related to the dry conditions of the Hypsithermal Interval. The silt layer also serves as an arsenic source. Results indicate that deltaic silts derived from organic-rich shale parent materials in a glacial environment can provide long-term sources for sulfate and arsenic and possibly other related oxidative weathering products.

  4. Bioturbating animals control the mobility of redox-sensitive trace elements in organic-rich mudstone

    SciTech Connect

    Harazim, Dario; McIlroy, Duncan; Edwards, Nicholas P.; Wogelius, Roy A.; Manning, Phillip L.; Poduska, Kristin M.; Layne, Graham D.; Sokaras, Dimosthenis; Alonso-Mori, Roberto; Bergmann, Uwe

    2015-10-07

    Bioturbating animals modify the original mineralogy, porosity, organic content, and fabric of mud, thus affecting the burial diagenetic pathways of potential hydrocarbon source, seal, and reservoir rocks. High-sensitivity, synchrotron rapid scanning X-ray fluorescence elemental mapping reveals that producers of phycosiphoniform burrows systematically partition redox-sensitive trace elements (i.e., Fe, V, Cr, Mn, Co, Ni, Cu, and As) in fine-grained siliciclastic rocks. Systematic differences in organic carbon content (total organic carbon >1.5 wt%) and quality (Δ13Corg~0.6‰) are measured between the burrow core and host sediment. The relative enrichment of redox-sensitive elements in the burrow core does not correlate with significant neo-formation of early diagenetic pyrite (via trace metal pyritization), but is best explained by physical concentration of clay- and silt-sized components. A measured loss (~–15%) of the large-ionic-radius elements Sr and Ba from both burrow halo and core is most likely associated with the release of Sr and Ba to pore waters during biological (in vivo) weathering of silt- to clay-sized lithic components and feldspar. In conclusion, this newly documented effect has significant potential to inform the interpretation of geochemical proxy and rock property data, particularly from shales, where elemental analyses are commonly employed to predict reservoir quality and support paleoenvironmental analysis.

  5. Bioturbating animals control the mobility of redox-sensitive trace elements in organic-rich mudstone

    DOE PAGES

    Harazim, Dario; McIlroy, Duncan; Edwards, Nicholas P.; ...

    2015-10-07

    Bioturbating animals modify the original mineralogy, porosity, organic content, and fabric of mud, thus affecting the burial diagenetic pathways of potential hydrocarbon source, seal, and reservoir rocks. High-sensitivity, synchrotron rapid scanning X-ray fluorescence elemental mapping reveals that producers of phycosiphoniform burrows systematically partition redox-sensitive trace elements (i.e., Fe, V, Cr, Mn, Co, Ni, Cu, and As) in fine-grained siliciclastic rocks. Systematic differences in organic carbon content (total organic carbon >1.5 wt%) and quality (Δ13Corg~0.6‰) are measured between the burrow core and host sediment. The relative enrichment of redox-sensitive elements in the burrow core does not correlate with significant neo-formation ofmore » early diagenetic pyrite (via trace metal pyritization), but is best explained by physical concentration of clay- and silt-sized components. A measured loss (~–15%) of the large-ionic-radius elements Sr and Ba from both burrow halo and core is most likely associated with the release of Sr and Ba to pore waters during biological (in vivo) weathering of silt- to clay-sized lithic components and feldspar. In conclusion, this newly documented effect has significant potential to inform the interpretation of geochemical proxy and rock property data, particularly from shales, where elemental analyses are commonly employed to predict reservoir quality and support paleoenvironmental analysis.« less

  6. Sulfur isotope fractionation during bacterial sulfate reduction in organic-rich sediments.

    PubMed

    Habicht, K S; Canfield, D E

    1997-12-01

    Isotope fractionation during sulfate reduction by natural populations of sulfate-reducing bacteria was investigated in the cyanobacterial microbial mats of Solar Lake, Sinai and the sediments of Logten Lagoon sulfuretum, Denmark. Fractionation was measured at different sediment depths, sulfate concentrations, and incubation temperatures. Rates of sulfate reduction varied between 0.1 and 37 micromoles cm-3 d-1, with the highest rates among the highest ever reported from natural sediments. The depletion of 34S during dissimilatory sulfate reduction ranged from 16% to 42%, with the largest 34S-depletions associated with the lowest rates of sulfate reduction and the lowest 34S-depletions with the highest rates. However, at high sulfate reduction rates (>10 micromoles cm-3 d-1) the lowest fractionation was 20% independent of the rates. Overall, there was a similarity between the fractionation obtained by the natural populations of sulfate reducers and previous measurements from pure cultures. This was somewhat surprising given the extremely high rates of sulfate reduction in the experiments. Our results are explained if we conclude that the fractionation was mainly controlled by the specific rate of sulfate reduction (mass cell-1 time-1) and not by the absolute rate (mass volume-1 time-1). Sedimentary sulfides (mainly FeS2) were on average 40% depleted in 34S compared to seawater sulfate. This amount of depletion was more than could be explained by the isotopic fractionations that we measured during bacterial sulfate reduction. Therefore, additional processes contributing to the fractionation of sulfur isotopes in the sediments are indicated. From both Solar Lake and Logten Lagoon we were able to enrich cultures of elemental sulfur-disproportionating bacteria. We suggest that isotope fractionation accompanying elemental sulfur disproportionation contributes to the 34S depletion of sedimentary sulfides at our study sites.

  7. The Role of Cable Bacteria on Porewater Acidity in an Organic Rich Coastal Sediment

    NASA Astrophysics Data System (ADS)

    Malkin, S.; Rao, A. M. F.; Seitaj, D.; Burdorf, L. D.; Hidalgo-Martinez, S.; Tramper, A.; Meysman, F. J. R.

    2016-02-01

    Sulphide generating coastal sediments are characterised by steep redox gradients. To connect energetically favorable electron donors and acceptors in such sediments, a variety of different microbial strategies have evolved. For example, the well-known sulphur oxidizing bacteria Beggiatoa can acquire nitrate near the sediment surface and transport this electron acceptor deeper in the sediment to oxidize sulphide. Recently, a very different bacterial sulphur oxidizing lifestyle was described in marine sediments. Cable bacteria (family Desulfobulbaceae) grow as long filaments capable of conducting electrons across centimeter-scale distances, from deep reducing sediments up to surface oxic sediments. Ex situ sediment incubation experiments have shown that cable bacteria can exert a powerful control on porewater pH and associated sediment geochemistry. Yet, the biogeography of these novel bacteria, and their influence on sediment geochemistry in natural environments, is not yet well understood. Here we report on a study carried out at an intertidal mussel bed and an oyster reef in the Wadden Sea (The Netherlands). In all sediments examined, nitrate-storing Beggiatoa were nearly absent, while cable bacteria were consistently abundant, with densities reaching up to 1038 m cm-2. Microsensor profiling revealed acidity distributions that were expected for sediments hosting cable bacteria, with pH maxima near the sediment surface (up to 8.3), and pH minima near the sulphide horizon (down to 6.1). Porewater analyses revealed strongly elevated concentrations of dissolved calcium (< 35 mM), manganese (up to 250 µM), and iron (up to 700 µM), consistent with acidity-driven dissolution of calcium carbonates and iron sulphides associated with cable bacteria activity. Overall, cable bacteria are shown to exert a powerful control on the sediment acidity of coastal bivalve bed sediments, which may have broad implications, particularly for sediment alkalinity fluxes and for carbonate

  8. Distribution and speciation of ambient selenium in contrasted soils, from mineral to organic rich.

    PubMed

    Tolu, Julie; Thiry, Yves; Bueno, Maïté; Jolivet, Claudy; Potin-Gautier, Martine; Le Hécho, Isabelle

    2014-05-01

    Selenium adsorption onto oxy-hydroxides mainly controls its mobility in volcanic soils, red earths and soils poor in organic matter (OM) while the influence of OM was emphasized in podzol and peat soils. This work aims at deciphering how those solid phases influence ambient Se mobility and speciation under less contrasted conditions in 26 soils spanning extensive ranges of OM (1-32%), Fe/Al oxy-hydroxides (0.3-6.1%) contents and pH (4.0-8.3). The soil collection included agriculture, meadow and forest soils to assess the influence of OM quality as well. Trace concentrations of six ambient Se species (Se(IV), Se(VI) and 4 organo-Se compounds) were analyzed by HPLC-ICP-MS in three extractants (ultrapure water, phosphate and sodium hydroxide) targeting Se associated to different soil phases. The Kd values determined from ultrapure water extraction were higher than those reported in commonly used short-term experiments after Se-spiking. Correlations of ambient Se content and distribution with soil parameters explained this difference by an involvement of slow processes in Se retention in soils. The 26 Kd values determined here for a wide variety of soils thus represent a relevant database for long-term prediction of Se mobility. For soils containing less than 20% OM, ambient Se solubility is primarily controlled by its adsorption onto crystalline oxy-hydroxides. However, OM plays an important role in Se mobility by forming organo-mineral associations that may protect adsorbed Se from leaching and/or create anoxic zones (aggregates) where Se is immobilized after its reduction. Although for the first time, inorganic Se(IV), Se(VI) and organo-Se compounds were simultaneously investigated in a large soil collection, high Se proportions remain unidentified in each soil extract, most probably due to Se incorporation and/or binding to colloidal-sized OM. Variations of environmental factors regulating the extent of OM-mineral associations/aggregation may thus lead to changes

  9. Iron and copper isotope fractionation during filtration and ultrafiltration of boreal organic-rich waters

    NASA Astrophysics Data System (ADS)

    Ilina, Svetlana M.; Viers, Jerome; Pokrovsky, Oleg S.; Poitrasson, Franck; Lapitsky, Sergey A.; Alekhin, Yuriy V.

    2010-05-01

    Typical feature of all boreal surface waters is high concentration of dissolved (< 0.22 µm) organic matter (DOM) and iron, notably in the form of Fe(III)-OM complexes. Organic and organo-mineral colloids are the most likely carriers of trace metals such as Cu in rivers of the boreal zone. This work addresses colloidal speciation of Cu and Fe using conventional size separation technique, on-site frontal ultrafiltration. Specifically, we aimed to test the possibility of the presence of different pools of metal having specific isotopic signatures in different colloidal fractions using stable isotope measurements. We have chosen Cu for its high affinity to colloidal DOM and Fe for its tendency to form stable organo-mineral colloids of various size. Samples of natural waters were collected from small rivers, lakes, bogs, groundwater and soil environments in the Northern Karelia (NW Russia) during summer baseflow period. Large volumes (20-40 L) of water were filtered in the field through progressively decreasing pore size filters: 20, 10, 5, 0.8, 0.45, 0.22, 0.1 µm and 100, 10 and 1 kDa (1 kDa ~ 1 nm) using nylon and regenerated cellulose membranes and frontal ultrafiltration (Millipore, Amicon) devises. The homogeneity of the sample was verified by tracing radiogenic Sr isotopes in each fraction. In all filtrates and ultrafiltrates (permeates), and in selected retentates, stable isotopic composition of Cu and Fe was measured using double focusing high resolution MC-ICP MS (Neptune). We observe rather constant Cu isotopic ratio in all filtrate series and a systematic enrichment of heavy isotope of Fe with decreasing poresize. These preliminary results can be explained by strong complexation of Cu with small-size organic ligands of fulvic nature and its partial association with organo-mineral colloids. Both Fe(III) - OM complxeation and Fe(III) oxyhydroxides precipitation can be invoked to explain Fe isotope fractionation. This work allows, for the first, time, multi

  10. Sub-cellular partitioning of essential and non-essential metals in a freshwater mollusc, Pyganodon grandis, collected in the field along a polymetallic environmental gradient

    NASA Astrophysics Data System (ADS)

    Bonneris, E.; Giguère, A.; Masson, S.; Campbell, P. G. C.

    2003-05-01

    The cellular alterations normally induced by metals at high concentrations can be prevented by detoxification processes [1] such as sequestration into cellular compartments (calcium concretions, lysosomes, etc.) or their binding to specifie cellular ligands like metallothionein [2]. The aim of this project was to study and compare the subcellular partitioning of three metals (Cd, Cu, Zn) in gills of a freshwater mollusc, Pyganodon grandis, collected along a polymetallic environmental gradient (nine lakes in the Rouyn-Noranda area, Abitibi, QC, Canada). Differential centrifugation was used to partition metals among different subcellular fractions. In the gills, along the environmental metal gradient, total tissue metal concentrations were positively correlated with concentrations in the granule fraction; gill tissues contained high amounts of calcium concretions, which acted as preferential sites for sequestration of the three metals. An increase in Cd concentration was observed in the heat stable proteins fraction (including metallothionein), but not in the heat-denatured proteins fraction, suggesting that Cd-induced cell injury could be prevented by the involement of multiple cellular compartments in a protective role.

  11. Field transplantation of the freshwater bivalve Corbicula fluminea along a polymetallic contamination gradient (River Lot, France): 2. Metallothionein response to metal exposure

    SciTech Connect

    Baudrimont, M.; Andres, S.; Metivaud, J.; Lapaquellerie, Y.; Ribeyre, F.; Maillet, N.; Latouche, C.; Boudou, A.

    1999-11-01

    Specimens of the Asiatic clam Corbicula fluminea were transplanted from a clean lacustrine site to four stations along a polymetallic pollution gradient in the river Lot, France, downstream from an old Zn ore treatment facility (see Part 1). From April to September 1996, the authors studied Cd and Zn bioaccumulation and the metallothionein-like metal-binding protein (MT) concentrations by subsampling the ages at t = 0, 21, 49, 85, 120, and 150 d. Marked differences were observed among the four stations. At the most polluted station Riou-Mort, MT concentrations did not increase despite very rapid metal accumulation; all mollusks died between days 49 and 85, suggesting that the metal detoxification mechanisms were overwhelmed at this station. At the next station downstream, the final levels of bioaccumulated metal after 150 d were as high as those at the Riou-Mort station, but in this case the MT concentrations also increased progressively with positive correlations between MT and metal concentrations; no mortality was observed, but a significant growth inhibition was revealed in comparison to the reference site, with a lack of correlation between MT and reduced growth. Subcellular metal partitioning, as determined by size-exclusion chromatography, revealed that most of the Cd was sequestered by MT. In contrast, most of the Zn was bound to low molecular weight proteins, the MT fraction representing only 12% of cytosolic zn. These data show the marked role of MT toward Cd bioaccumulation and toxic effects on this freshwater bivalve species.

  12. Geochemical hunting of lithogenic and anthropogenic impacts on polymetallic distribution (Bregalnica river basin, Republic of Macedonia).

    PubMed

    Balabanova, Biljana; Stafilov, Trajče; Šajn, Robert; Tănăselia, Claudiu

    2016-11-09

    The main subject of this investigation was the assessment of the lithogenic and anthropogenic distribution of 69 elements in the sediments and fluvisol in the Bregalnica river basin. Alluvial soil and fluvisol samples were collected from the total of eighteen locations along the course of the Bregalnica river and additional thirteen samples were collected from its tributaries. The matrix elements accumulation patterns followed the order: Fe > Na > Al > Ca > Mg > K > Ti > P. The potentially toxic elements, such as As, Cd, Pb, and Zn, have enriched content in the sediments in the medium course of the river, where the main anthropogenic introduction activities occurred. By multivariate analysis the dominant geochemical associations were extracted, as follows: F1: Y-Eu-Lu-Cr-V-La-Gd-Nb-Co-Hf-Zr-Ga-Mg-Fe-Sr-Ta-Sn-Li-Na-Rb-Ni-Ge-Be-Cs; F2: As-W-Ba-Ag-Cu-Tl-Zn-Sb-Mo-In-Cd-Te-Bi-Pb and F3: I-Sc-Br-K. Lead and zinc contents were strongly correlated with the hydrothermal exploitations, especially in the area of Neogene clastite and vulcanite. These elements occur as dominant geochemical markers of the anthropogenic impacts of polymetallic enrichments due to the hydrothermal ore exploitation (Factor 2). The impact of Oligocene volcanism (Kratovo-Zletovo region) was observed in the lithological enrichments of Pb, Zn, Cu, As, Sb, Mo and Bi. Despite the natural distribution along the course of the Bregalnica river, an exceptional anomaly in the iron distribution of the old polymetallic unused mineralization was detected in Zone 1 (Berovo region).

  13. δ15N changes during Paleogene climatic events in organic-rich, marine clays from coastal Tanzania

    NASA Astrophysics Data System (ADS)

    O'Halloran, A.; Nicholas, C. J.; Goodhue, R.

    2007-12-01

    A mid- to outer-shelf, passive margin sequence, consisting of organic-rich marine clays, has been cored by the Tanzanian Drilling Project (TDP) on southern coastal Tanzania. Drilling recovered an expanded Paleogene section -- from latest Cretaceous to early Oligocene. Intervals cored include at least two periods of global climatic change: the Paleocene-Eocene Thermal Maximum (PETM), and the Eocene-Oligocene boundary. The organic- rich nature of these clays makes them ideal for nitrogen isotope analysis across these global climate change boundaries. Shifts in the δ15N of sediments represent changes in the primary productivity regime of the local ocean at that time. An increased or high δ15N signal in sediment corresponds to regions of greater nitrate depletion in the surface waters (i.e. higher productivity). A low δ15N signal represents a lack of nitrate uptake in the surface waters, possibly due to phytoplankton migration, phytoplankton collapse or lack of nutrient supply. A sharp and significant decrease in δ15N is seen at the onset of the PETM. This negative shift in δ15N coincides with an extinction of benthic foraminifera at this site and may indicate a broader ecosystem collapse. Productivity collapse is a likely result of switching off the nutrient supply to the planktonic biomass. This may indicate stratification of the water column -- much like that seen during El Niño events, but over a longer timescale. Preliminary investigations of mineralogy across the Eocene-Oligocene boundary have indicated that through the transition, increased amounts of detrital material (e.g. SiO2) entered the coastal system. The increasing abundances of detrital quartz are coeval with increases in Ti/Al ratios, also indicating increased terrigenous input. A likely cause is the lowering of global sea-levels during initiation of glaciation on Antarctica. Analyses of the Fe/Al and Ba/Al ratios of the sediments indicate brief periods of increased productivity after the

  14. The geochemistry of water near a surficial organic-rich uranium deposit, northeastern Washington State, U.S.A.

    USGS Publications Warehouse

    Zielinski, R.A.; Otton, J.K.; Wanty, R.B.; Pierson, C.T.

    1987-01-01

    The chemistry of three stream, three spring and six near-surface waters in the vicinity of a Holocene organic-rich uranium deposit is described, with particular emphasis on the chemistry of U. Results characterize the solution behavior of uranium as U-bearing water interacts with relatively undecomposed, surficial organic matter. Of the measured major and trace chemical species, only U is consistently highly enriched (17-318 ppb) relative to reported values for regional waters, or to literature values for waters in largely granitic terrains. R-mode factor analysis of the chemical data suggests that most U is present in a soluble form, but that some U is also associated with fine suspended particulates of clay, organic matter, or hydrous oxides. Calculations that apply thermodynamic data to predict U speciation in solution indicate the relative importance of uranyl carbonate and uranyl phosphate complexes. Analysis of more finely filtered samples (0.05 ??m vs. 0.45 ??m), and direct radiographic observations using fission-track detectors suspended in the waters indicate the presence of some uraniferous particulate matter. Application of existing thermodynamic data for uranous- and uranyl-bearing minerals indicates that all waters are undersaturated with U minerals as long as ambient Eh ??? +0.1 v. If coexisting surface and near-surface waters are sufficiently oxidizing, initial fixation of U in the deposit should be by a mechanism of adsorption. Alternatively, more reducing conditions may prevail in deeper pore waters of the organic-rich host sediments, perhaps leading to direct precipitation or diagenetic formation of U4+ minerals. A 234U 238U alpha activity ratio of 1.08 ?? 0.02 in a spring issuing from a hillslope above the deposit suggests a relatively soluble source of U. In contrast, higher activity ratios of 234U 238U (??? 1.3) in waters in contact with the uraniferous valley-fill sediments suggest differences in the nature of interaction between groundwater

  15. Effects of sedimentary sulfide on community structure, population dynamics, and colonization depth of macrozoobenthos in organic-rich estuarine sediments.

    PubMed

    Kanaya, Gen; Uehara, Tadayasu; Kikuchi, Eisuke

    2016-08-15

    An annual field survey and in situ recolonization experiment revealed the effects of sedimentary sulfide (H2S) on macrozoobenthos in a eutrophic brackish lagoon. Species diversity was much lower throughout the year in muddy opportunist-dominant sulfidic areas. Mass mortality occurred during warmer months under elevated H2S levels. An enclosure experiment demonstrated that sedimentary H2S modified community composition, size structure, and colonization depth of macrozoobenthos. Species-specific responses to each sediment type (sand, sulfidic mud, and mud with H2S removed) resulted in changes in the established community structure. Dominant polychaetes (Hediste spp., Pseudopolydora spp., and Capitella teleta) occurred predominantly in a thin surface layer in the presence of H2S. On the other hand, organic-rich mud facilitated settlement of polychaete larvae if it does not contain H2S. These results demonstrate that sediment characteristics, including H2S level and organic content, were key structuring factors for the macrozoobenthic assemblage in organically polluted estuarine sediments.

  16. Determination of factors responsible for the bioweathering of copper minerals from organic-rich copper-bearing Kupferschiefer black shale.

    PubMed

    Włodarczyk, Agnieszka; Szymańska, Agata; Skłodowska, Aleksandra; Matlakowska, Renata

    2016-04-01

    The aim of this study was to investigate the bioweathering of copper minerals present in the alkaline, copper-bearing and organic-rich Kupferschiefer black shale through the action of a consortium of indigenous lithobiontic, heterotrophic, neutrophilic bacteria isolated from this sedimentary rock. The involvement of microorganisms in the direct/enzymatic bioweathering of fossil organic matter of the rock was confirmed. As a result of bacterial activity, a spectrum of various organic compounds such as urea and phosphoric acid tributyl ester were released from the rock. These compounds indirectly act on the copper minerals occurring in the rock and cause them to weather. This process was reflected in the mobilization of copper, iron and sulfur and in changes in the appearance of copper minerals observed under reflected light. The potential role of identified enzymes in biodegradation of fossil organic matter and role of organic compounds released from black shale as a result of this process in copper minerals weathering was discussed. The presented results provide a new insight into the role of chemical compounds released by bacteria during fossil organic matter bioweathering potentially important in the cycling of copper and iron deposited in the sedimentary rock. The originality of the described phenomenon lies in the fact that the bioweathering of fossil organic matter and, consequently, of copper minerals occur simultaneously in the same environment, without any additional sources of energy, electrons and carbon.

  17. Comparison of three extraction methods for 17beta-estradiol in sand, bentonite, and organic-rich silt loam.

    PubMed

    Chun, Soul; Lee, Jaehoon; Geyer, Roland; White, David C

    2005-01-01

    Extraction is an important procedure for samples that contain soil because other compounds in soil may affect analysis of estrogens. This study was conducted to evaluate three different extraction methods for 17beta-estradiol in soil. Sand, bentonite, and organic-rich silt loam were spiked with 1 mg kg(-1) of 17beta-estradiol as a model compound of estrogens. 17beta-estradiol and its metabolites, estrone and estriol, were extracted using (i) a modified Bligh and Dyer extraction, (ii) a pressurized fluid extraction, and (iii) a diethyl ether extraction, and measured by liquid chromatography tandem mass spectrometry. There were significant differences in the extraction efficiency for 17beta-estradiol among the extraction methods and the soils: the efficiencies ranged from 10% to 97%. Overall, the diethyl ether extraction method had the largest efficiency of 17beta-estradiol with 45% and 57% for bentonite and silt loam, respectively. Transformation of 17beta-estradiol to estrone and estriol in the different extraction methods was less than 3.6% during the extraction procedures. This study underlined the importance of sample preparation for estrogen analysis in soil samples.

  18. Experimental and theoretical enhancement of the inversion accuracy of the Thomsen parameter δ in organic-rich shale

    NASA Astrophysics Data System (ADS)

    Xie, Jianyong; Wei, Jianxin; Di, Bangrang; Xu, Kaichi; Chen, Yangkang

    2016-12-01

    Experimental physical inversion of rock from the diagonal group velocities is an effective method for the determination of Thomsen’s δ anisotropy parameter in organic-rich shale. We further enhance the inversion accuracy of δ through conducting more reliable experimental measurements and through theoretical expression. First, we assembled two sets of group velocity acquisition methods, a rotational ultrasonic transducer system and a laser ultrasonic system, and then we assessed which of them was more applicable and accurate by comparing the waveforms and observations on the same cylindrical organicrich shale. Second, we combined the δ-based phase velocity approximation and stricter physical constraints of δ, which are deduced on a standard VTI medium, to improve the theoretical part of the inversion. As a result of better observations by the optimal test methods and the proposed δ inversion methods, the least errors between the best fitted curve to the observations are 3.24% for the traditional method and 2.1% for the proposed method, which verifies the superiority of the proposed method. Based on experimental tests on two cylindrical shale specimens, we find that rotational ultrasonic transducer measurement is more applicable for quick velocity anisotropy measurements, while for observations obtained by the laser technique, system relative error and the necessary scattering effect processing should be conducted. The procedure of the inversion is more robust and accurate when conducted on the proposed δ-based inversion.

  19. Alkyl amides in two organic-rich anoxic sediments: A possible new abiotic route for N sequestration

    NASA Astrophysics Data System (ADS)

    McKee, Georgina A.; Hatcher, Patrick G.

    2010-11-01

    Fixed nitrogen (N) plays an integral role in global cycling; while most is recycled to refuel primary productivity, a small fraction escapes to be preserved and stabilised in sediments. Despite decades of research, the functionality and reactivity of this sequestered organic N has been poorly understood. This study was undertaken to shed light on this problem by characterising the bulk sediment organic matter using nuclear magnetic resonance (NMR), followed by molecular level analysis using ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS). We studied two organic-rich anaerobic sediments, one from a freshwater system and another from a marine paralic basin. Mangrove Lake, Bermuda (marine) and Mud Lake, Florida (freshwater) have been shown in past studies to contain high levels of N-containing organic matter. Our resulting multidimensional NMR data suggests the existence of a new type of amide functionality in both these lake sediments, and we investigated this further using FT-ICR-MS and gas chromatography mass spectrometry (GC-MS). FT-ICR-MS confirmed the existence of homologous series of CHNO containing compounds, whose structures are verified using GC-MS as alkyl amides. Model reactions involving naturally occurring esters and ammonia suggest the source of alkyl amides to be amidation of esters with sedimentary ammonia derived from anaerobic degradation of organic matter. This expands upon previous hypotheses for preservation of amide containing compounds that call upon biological/abiological protection of proteins and peptides or the formation of refractory nitrogenous adducts.

  20. Model of the porphyry copper and polymetallic vein family of deposits - Applications in Slovakia, Hungary, and Romania

    USGS Publications Warehouse

    Drew, L.J.

    2003-01-01

    A tectonic model useful in estimating the occurrence of undiscovered porphyry copper and polymetallic vein systems has been developed. This model is based on the manner in which magmatic and hydrothermal fluids flow and are trapped in fault systems as far-field stress is released in tectonic strain features above subducting plates (e.g. strike-slip fault systems). The structural traps include preferred locations for stock emplacement and tensional-shear fault meshes within the step-overs that localize porphyry- and vein-style deposits. The application of the model is illustrated for the porphyry copper and polymetallic vein deposits in the Central Slovakian Volcanic Field, Slovakia; the Ma??tra Mountains, Hungary; and the Apuseni Mountains, Romania.

  1. Metallic elements and metalloids in Boletus luridus, B. magnificus and B. tomentipes mushrooms from polymetallic soils from SW China.

    PubMed

    Falandysz, Jerzy; Zhang, Ji; Wiejak, Anna; Barałkiewicz, Danuta; Hanć, Anetta

    2017-08-01

    Yunnan Province in China is known for its high biodiversity of mushrooms and a diverse geochemistry of soil bedrock and polymetallic soils, but our knowledge of mineral compositions of mushrooms from Yunnan is scarce. The metallic trace elements, Ag, Ba, Co, Cd, Cs, Cu, Cr, Hg, Li, Mn, Ni, Pb, Rb, Sr, V, Tl, U and Zn, and the metalloids, As and Sb, have been investigated using validated methods with a dynamic reactive cell by mass spectroscopy - inductive coupled plasma and cold vapour - atomic absorption spectroscopy on three popular species of Boletus mushrooms from Southwestern China. The trace mineral profiles in caps and stipes of B. luridus (24 individuals), B. magnificus (29 individuals) and B. tomentipes (38 individuals) have been evaluated. The interspecific differences in the content of several trace elements could be attributed to known differences in the geochemistry of soils in Yunnan, but for copper a difference was observed within species. The mean values of concentrations in composite samples of caps for B. luridus, B. magnificus and B. tomentipes from three to four locations were at the ranges (mgkg(-1) dry biomass): Ag (1.3-3.7), As (0.79-53), Ba (4.0-12), Co (0.68-1.2), Cd (0.79-2.2), Cs (0.67-55), Cu (37-77), Cr (5.0-7.6), Hg (2.1-5.4), Li (0.15-0.61), Mn (13-28), Ni (0.86-4.6), Pb (0.59-1.8), Rb (90-120), Sb (0.014-0.088), Sr (0.63-1.6), V (1.4-2.2), Tl (0.017-0.054), U (0.029-0.065) and Zn (130-180). Caps of Boletus mushrooms were richer in Ag, Cu, Hg and Zn than stipes, while other elements were distributed roughly equally between both morphological parts. B. luridus, B. magnificus and B. tomentipes grew in certain sites in Yunnan contained Ag, As, Ba, Cr, Hg, Ni, Sr or V at elevated concentration. A specific geochemistry of the soils type (latosols, lateritic red earths, and red and yellow earths in the Circum-Pacific Mercuriferous Belt of Southwestern China) can explain occurrence of some minerals at greater or elevated amount in mushrooms

  2. Determination of Natural 14C Abundances in Dissolved Organic Carbon in Organic-Rich Marine Sediment Porewaters by Thermal Sulfate Reduction

    NASA Astrophysics Data System (ADS)

    Johnson, L.; Komada, T.

    2010-12-01

    value of 0.54±0.05 fMC. The size of the blank agreed well with that determined directly by processing variable volumes of UV-irradiated deionized water (5.6±0.7 μgC, n=9). The size of the blank amounts to <~5% of the size of porewater DOC samples that are typically recovered from organic-rich sediment cores (~100-500 μgC). The fMC value of the blank suggests that there may be multiple sources of extraneous carbon that range in 14C abundance. In order to assess the fidelity of 14C abundances in natural porewater DOC oxidized by thermal sulfate reduction, we oxidized porewater DOC samples collected from the central floor of the Santa Monica Basin, California Borderland, using both this method and UV irradiation (the latter carried out at the Druffel laboratory, University of California Irvine). The fMC values obtained by the two methods agreed within error. Carbon yields from the two methods also agreed closely. These findings show that thermal sulfate reduction may be a promising method to oxidize small, concentrated marine DOC samples for 14C analysis.

  3. Pollution level and inhalation exposure of ambient aerosol fluoride as affected by polymetallic rare earth mining and smelting in Baotou, north China

    NASA Astrophysics Data System (ADS)

    Zhong, Buqing; Wang, Lingqing; Liang, Tao; Xing, Baoshan

    2017-10-01

    Airborne fluoride associated with total suspended particles (TSP) and respirable particulate (PM10) in the rare earth mining and smelting areas were analyzed during August 2012 and March 2013. In March, average concentrations of fluoride bound to TSP in the mining and smelting areas were 0.598 ± 0.626 μg/m3 and 3.615 ± 4.267 μg/m3, respectively, whereas that in August were 0.699 ± 0.801 μg/m3 and 1.917 ± 2.233 μg/m3, respectively. TSP samples were classified into four categories by different sampling periods and locations using Kohonen's self-organizing map, which demonstrates that high airborne fluoride concentrations in March in the smelting area were probably attributed to industrial emissions from smelting activities and wind-blown dust from tailings pond, influenced by meteorologic parameters such as temperature, relative humidity, precipitation and wind speed. The mean daily amount of fluoride inhaled in the mining and smelting areas were estimated to be in the range of 2.77-57.61 μg/day and 3.39-64.32 μg/day, respectively. These results indicate the high potential exposure level of fluoride inhaled for local residents in the polymetallic mining and smelting areas.

  4. Carbon isotopes and lipid biomarkers from organic-rich facies of the Shuram Formation, Sultanate of Oman.

    PubMed

    Lee, C; Fike, D A; Love, G D; Sessions, A L; Grotzinger, J P; Summons, R E; Fischer, W W

    2013-09-01

    The largest recorded carbon isotopic excursion in Earth history is observed globally in carbonate rocks of middle Ediacaran age. Known from the Sultanate of Oman as the 'Shuram excursion', this event records a dramatic, systematic shift in δ(13) Ccarbonate values to ca. -12‰. Attempts to explain the nature, magnitude and origin of this excursion include (i) a primary signal resulting from the protracted oxidation of a large dissolved organic carbon reservoir in seawater, release of methane from sediment-hosted clathrates, or water column stratification; and (ii) a secondary signal from diagenetic processes. The compositions and isotope ratios of organic carbon phases during the excursion are critical to evaluating these ideas; however, previous work has focused on localities that are low in organic carbon, hindering straightforward interpretation of the observed time-series trends. We report carbon isotope data from bulk organic carbon, extracted bitumen and kerogen, in addition to lipid biomarker data, from a subsurface well drilled on the eastern flank of the South Oman Salt Basin, Sultanate of Oman. This section captures Nafun Group strata through the Ediacaran-Cambrian boundary in the Ara Group and includes an organic-rich, deeper-water facies of the Shuram Formation. Despite the high organic matter contents, the carbon isotopic compositions of carbonates - which record a negative δ(13) C isotope excursion similar in shape and magnitude to sections elsewhere in Oman - do not covary with those of organic phases (bulk TOC, bitumen and kerogen). Paired inorganic and organic δ(13) C data only display coupled behaviour during the latter part of the excursion's recovery. Furthermore, lipid biomarker data reveal that organic matter composition and source inputs varied stratigraphically, reflecting biological community shifts in non-migrated, syngenetic organic matter deposited during this interval. © 2013 John Wiley & Sons Ltd.

  5. Synchrotron tomographic quantification of strain and fracture during simulated thermal maturation of an organic-rich shale, UK Kimmeridge Clay

    NASA Astrophysics Data System (ADS)

    Figueroa Pilz, Fernando; Dowey, Patrick J.; Fauchille, Anne-Laure; Courtois, Loic; Bay, Brian; Ma, Lin; Taylor, Kevin G.; Mecklenburgh, Julian; Lee, Peter D.

    2017-04-01

    Analyzing the development of fracture networks in shale is important to understand both hydrocarbon migration pathways within and from source rocks and the effectiveness of hydraulic stimulation upon shale reservoirs. Here we use time-resolved synchrotron X-ray tomography to quantify in four dimensions (3-D plus time) the development of fractures during the accelerated maturation of an organic-rich mudstone (the UK Kimmeridge Clay), with the aim of determining the nature and timing of crack initiation. Electron microscopy (EM, both scanning backscattered and energy dispersive) was used to correlatively characterize the microstructure of the sample preheating and postheating. The tomographic data were analyzed by using digital volume correlation (DVC) to measure the three-dimensional displacements between subsequent time/heating steps allowing the strain fields surrounding each crack to be calculated, enabling crack opening modes to be determined. Quantification of the strain eigenvectors just before crack propagation suggests that the main mode driving crack initiation is the opening displacement perpendicular to the bedding, mode I. Further, detailed investigation of the DVC measured strain evolution revealed the complex interaction of the laminar clay matrix and the maximum principal strain on incipient crack nucleation. Full field DVC also allowed accurate calculation of the coefficients of thermal expansion (8 × 10-5/°C perpendicular and 6.2 × 10-5/°C parallel to the bedding plane). These results demonstrate how correlative imaging (using synchrotron tomography, DVC, and EM) can be used to elucidate the influence of shale microstructure on its anisotropic mechanical behavior.

  6. Three magnetic reversals recorded in an 80-m organic-rich core from a sinkhole east of Tampa, FL

    SciTech Connect

    McCartan, L.; Rubin, M. ); Liddicoat, J.C. ); Bond, P.A.; Osmond, J.K. )

    1994-03-01

    Preliminary analysis of a continuous 80-m core from a phosphate mines at Bartow, Fla., indicates as many as three magnetically reversed and five normal sections and five upward-fining depositional sequences. The paleomagnetic data are based on analysis of 16 samples; 100 additional samples have been taken for more detailed analysis. The authors estimate the maximum age to be 1.1--2.6 Ma. The core is composed of massive to faintly laminated beds of black to dark-brown, organic-rich, fine quartz sand and silt, kaolinitic and organic clay, and peat, Only the top meter is within the 40 Ka range of [sup 14]C; a sample at 8.5 m yielded an age estimate close to 350,000 years, the limit of the open-system U/Th dating technique. Rates of deposition are 2--7.5 cm/1,000 years, which is much slower than rates in late Quaternary lakes elsewhere in Florida. There is no clear relation between the magnetic stratigraphy and the depositional stratigraphy. The authors assume that most of the sand was derived from dissolved limestone around the sinkhole, but some of the sand as well as the silt and clay may be windborne. Textural variations may be coincident with differences in rainfall, and this concept will be investigated through pollen analysis of approximately 800 samples. The one sample examined so far is from the bottom of the core, and it has an equivocal biostratigraphic age. The high grass pollen content indicates a drier climate than at present; it is from a long interval of peat with sand, which is typically windborne in dry climates.

  7. Geological, fluid inclusion and isotopic studies of the Baiyangping Pb-Zn-Cu-Ag polymetallic deposit, Lanping basin, Yunnan province, China

    NASA Astrophysics Data System (ADS)

    Wang, Xiao-Hu; Hou, Zeng-Qian; Song, Yu-Cai; Zhang, Hong-Rui

    2015-11-01

    Baiyangping Pb-Zn-Cu-Ag deposit is located in Lanping basin, northwestern Yunnan province. The deposit is composed of a few ore veins and can be divided into several ore blocks. The ore bodies are primarily hosted in Mesozoic carbonate, sandstone and siltstone along the north-south-striking, NWW-striking and NE-SW-striking fault zones. There are breccia, massive, vein like and disseminated ores. The main ore minerals are sphalerite, galena, gratonite, jordanite, tetrahedrite series minerals, chalcocite, chalcopyrite, realgar, orpiment, bournonite, cobalt-bearing arsenopyrite, argentite, kongsbergite, cobaltine, siegenite. The sizes of fluid inclusions in Baiyangping deposit are generally less than 10 μm and have the shape of round, oval, irregular, etc. The ore-forming fluid system is Ca2+-Na+-K+-Mg2+-Cl--F--NO3- brine system. The freezing temperature of fluid inclusions in mineral deposits ranges from -26.4 to -0.2 °C, average -14.6 °C; the homogenization temperature is concentrated in 120-180 °C, and the salinity is between 0.35 and 24.73 wt% (NaCleq), average 16.9 wt% (NaCleq). δ13CPDB and δ18OSMOW values of hydrothermal calcite range from -4.16‰ to 3‰ and -2.5‰ to 20.4‰, respectively. δ34S values of sulfide minerals range from -10.2‰ to 11.2‰, average 5.6‰. The sulfide samples yield 206Pb/204Pb values of 18.609-18.818, 207Pb/204Pb of 15.548-15.842 and 208Pb/204Pb = 38.514-39.556. C-O-S-Pb isotope compositions of the Baiyangping deposit indicate a homogeneous carbon source, and the carbon in hydrothermal calcite is derived from the dissolution of carbonate rock strata, the ore-forming fluid belongs to basin brine fluid system, which is mixed with the precipitate water, sulfur in sulfides and sulfosalts is derived from thermal chemical sulfate reduction, and the thermal decomposition of sulfur-bearing organic matter. The metal mineralization material is from sedimentary strata and basement. The late Pb-Zn polymetallic mineralization event

  8. Time-domain electromagnetic signatures of polymetallic vein deposits in Cottonwood Canyon area, Santa Cruz County, Arizona

    USGS Publications Warehouse

    Bultman, Mark W.

    2002-01-01

    This report tests the usefulness of airborne time-domain electromagnetic (TEM) data on three mineral-resource-related issues: (1) to test whether known mineral deposits at or near the surface display any signal in the TEM data; 2) determine whether TEM data can be used to locate bedrock concealed by basin fill; and (3) if the exposed mineral deposits display a signal in the TEM data, to determine if whether deposits are recognizable at depth in outcropping bedrock or in bedrock concealed beneath basin fill. Because Earth's total-intensity magnetic field data are also acquired with the TEM data, these data are included in the analysis. The Cottonwood Canyon area in Santa Cruz County, Arizona, contains several polymetallic vein deposits, including those of the Tyndall, Salero, and Wrightson mining districts, all of which have had significant mineral production. Polymetallic vein deposits, which generally consist of veins of disseminated metallic minerals, commonly exhibit a response to electrical geophysical methods. Also, on the basis of other studies, the conditions that produced the polymetallic vein mineralization in the region are believed to extend offshore into the bedrock concealed by basin fill. The polymetallic vein deposits of the Cottonwood Canyon area all display a geophysical signature in the TEM data. These deposits occur in bedrock that has, in general, a very low resistivity. The polymetallic vein deposits are associated with high-conductivity regions that extend from deep in the bedrock to the surface. These high-conductivity regions can be quite narrow (100 m) or quite wide (1 km); most are relatively narrow. Every known mineral deposit or prospect is associated with a high-conductivity feature. High-conductivity regions can also occur without an association with known mineral deposits. Airborne TEM data appear to be able to locate the basin fill/bedrock contact beneath basin fill. The basin fill (both dry and saturated) is generally more

  9. Research on the growth orientation of pyrite grains in the colloform textures in Baiyunpu Pb-Zn polymetallic deposit, Hunan, China

    NASA Astrophysics Data System (ADS)

    Gao, Shang; Huang, Fei; Gu, Xiangping; Chen, Zhenyu; Xing, Miaomiao; Li, Yongli

    2017-02-01

    A large number of colloform-textured pyrites were found in Baiyunpu Pb-Zn ore bodies in Xinshao County, Hunan, China. This study investigates the growth orientation of the pyrite grains in these structures by field emission scanning electron microscopy (FE-SEM), in situ micro X-ray diffraction (μXRD) and electron backscatter diffraction (EBSD). The growth proceeded from micro-crystalline cores in the colloform textures. Moreover, the pyrite layers were discrete and separated by locally significant quantities of galena and calcite. The μXRD results suggested clear crystalline characteristics and weakly preferred orientations of the colloform textures. EBSD confirmed that the pyrite grains exist preferred orientations <100 > or <111 > in the layered zones. According to the crystal growth theory, the formation and variation of crystal preferred orientations (CPOs) in pyrite are mainly restricted by the internal crystal structure of the pyrite and depends on the external environment conditions, such as trace element concentrations and the supersaturation degree. We inferred the evolutionary regularity of lattice planes with different indices in the pyrite crystal structure from morphological, compositional and growth orientation information, which reflect the crystal growth history of the colloform pyrite. This study will advance our understanding of the growth processes of colloform pyrite and environmental evolution in the Baiyunpu Pb-Zn polymetallic deposits.

  10. Polymetallic nodules, sediments, and deep waters in the equatorial North Pacific exhibit highly diverse and distinct bacterial, archaeal, and microeukaryotic communities.

    PubMed

    Shulse, Christine N; Maillot, Brianne; Smith, Craig R; Church, Matthew J

    2017-04-01

    Concentrated seabed deposits of polymetallic nodules, which are rich in economically valuable metals (e.g., copper, nickel, cobalt, manganese), occur over vast areas of the abyssal Pacific Ocean floor. Little is currently known about the diversity of microorganisms inhabiting abyssal habitats. In this study, sediment, nodule, and water column samples were collected from the Clarion-Clipperton Zone of the Eastern North Pacific. The diversities of prokaryote and microeukaryote communities associated with these habitats were examined. Microbial community composition and diversity varied with habitat type, water column depth, and sediment horizon. Thaumarchaeota were relatively enriched in the sediments and nodules compared to the water column, whereas Gammaproteobacteria were the most abundant sequences associated with nodules. Among the Eukaryota, rRNA genes belonging to the Cryptomonadales were relatively most abundant among organisms associated with nodules, whereas rRNA gene sequences deriving from members of the Alveolata were relatively enriched in sediments and the water column. Nine operational taxonomic unit (OTU)s were identified that occur in all nodules in this dataset, as well as all nodules found in a study 3000-9000 km from our site. Microbial communities in the sediments had the highest diversity, followed by nodules, and then by the water column with <1/3 the number of OTUs as in the sediments.

  11. Parallel changes of taxonomic interaction networks in lacustrine bacterial communities induced by a polymetallic perturbation

    PubMed Central

    Laplante, Karine; Sébastien, Boutin; Derome, Nicolas

    2013-01-01

    Heavy metals released by anthropogenic activities such as mining trigger profound changes to bacterial communities. In this study we used 16S SSU rRNA gene high-throughput sequencing to characterize the impact of a polymetallic perturbation and other environmental parameters on taxonomic networks within five lacustrine bacterial communities from sites located near Rouyn-Noranda, Quebec, Canada. The results showed that community equilibrium was disturbed in terms of both diversity and structure. Moreover, heavy metals, especially cadmium combined with water acidity, induced parallel changes among sites via the selection of resistant OTUs (Operational Taxonomic Unit) and taxonomic dominance perturbations favoring the Alphaproteobacteria. Furthermore, under a similar selective pressure, covariation trends between phyla revealed conservation and parallelism within interphylum interactions. Our study sheds light on the importance of analyzing communities not only from a phylogenetic perspective but also including a quantitative approach to provide significant insights into the evolutionary forces that shape the dynamic of the taxonomic interaction networks in bacterial communities. PMID:23789031

  12. Phytoremediation of the toxic effluent generated during recovery of precious metals from polymetallic sea nodules.

    PubMed

    Vaseem, Huma; Banerjee, T K

    2012-01-01

    Recovery of metals from the polymetallic sea nodules at the pilot plant at National Metallurgical Laboratory, Jamshedpur, India has generated a highly toxic effluent. This effluent contains several metals like Mn, Cu, Zn, Fe, Pb, Cr, and Cd that pollute the neighboring water bodies when discharged. Hence detoxification of this effluent was practiced using two plants: Lemna minor and Azolla pinnata for 7 days. During investigation A. pinnata removed 96% of Mn, 97% of Cu, 98% of Zn, 70% of Fe, 96% of Pb, 93% of Cr, 78% of Cd, and was comparatively more effective than L. minor which removed 94% of Mn, 86% of Cu, 62% of Zn, 74% of Fe, 84% of Pb, 63% of Cr, 78% of Cd. During the 7 days of experiment chlorophyll content decreased by 51% and 59% in A. pinnata and L. minor respectively. Based on our findings we can suggest that these two plants have wide range of metal retention potentialities hence can be of routine use for purification of toxic effluents.

  13. Threatened by mining, polymetallic nodules are required to preserve abyssal epifauna

    PubMed Central

    Vanreusel, Ann; Hilario, Ana; Ribeiro, Pedro A.; Menot, Lenaick; Arbizu, Pedro Martínez

    2016-01-01

    Polymetallic nodule mining at abyssal depths in the Clarion Clipperton Fracture Zone (Eastern Central Pacific) will impact one of the most remote and least known environments on Earth. Since vast areas are being targeted by concession holders for future mining, large-scale effects of these activities are expected. Hence, insight into the fauna associated with nodules is crucial to support effective environmental management. In this study video surveys were used to compare the epifauna from sites with contrasting nodule coverage in four license areas. Results showed that epifaunal densities are more than two times higher at dense nodule coverage (>25 versus ≤10 individuals per 100 m2), and that taxa such as alcyonacean and antipatharian corals are virtually absent from nodule-free areas. Furthermore, surveys conducted along tracks from trawling or experimental mining simulations up to 37 years old, suggest that the removal of epifauna is almost complete and that its full recovery is slow. By highlighting the importance of nodules for the epifaunal biodiversity of this abyssal area, we urge for cautious consideration of the criteria for determining future preservation zones. PMID:27245847

  14. Reactivity of organic-rich sediment in seawater at 350°c, 500 bars: experimental and theoretical constraints and implications for the guaymas basin hydrothermal system

    NASA Astrophysics Data System (ADS)

    Thornton, Edward C.; Seyfried, W. E., Jr.

    1987-07-01

    Hydrothermal alteration of organic-rich diatomaceous sediment by seawater was modelled experimentally at 350°C, 500 bars and seawater/sediment mass ratio of 3. The experiment was performed to assess the effect of organic matter reactivity on solution speciation and sediment alteration processes at an elevated temperature and pressure and provide requisite data to better understand the chemistry of hydrothermal fluids issuing from vents in the Guaymas Basin, Gulf of California. Seawater chemistry changed greatly during the experiment. In particular, Na, Mg and SO 4 decreased, while ∑ CO 2, ∑ NH 3, ∑ H 2S, SiO 2, Ca, K, H 2, CH 4 and heavy and base metals increased. Moreover, owing to the thermal alteration of sediment organic matter, organic acids, phenolic derivatives and phthlate were released to solution. Examination of solid alteration products revealed the effects of extensive dissolution and precipitation processes characterized by total elimination of diatoms and formation of cristobalite, quartz (?), pyrite, pyrrhotite, mixed layer chlorite/smectite and calcite. Plagioclase feldspar (An 40) recrystallized to a more albitic form owing to Na fixation and Ca cycling to calcite. A graphitic residue was also present in the products of the experiment. Mg and Na fixation reactions during the experiment generated significant H +, although the pH measured at 25°C was approximately 6.2. SO 4 reduction and thermal alteration and dissolution of organics, however, consume H + and are chiefly responsible for the near neutral pH for the overall reaction. Speciation calculations including ammine and acetate protonation reactions give a pH at experimental conditions of approximately 5.1, while mineral solubility relations involving virtually all alteration phases require a pH of 5.57 to 5.94. A near neutral pH at experimental conditions constrains the mobility of Fe, Mn, Zn, Cu and Ni, which existed in solution as chloro-complexes. Dissolved concentrations of Pb and

  15. Confocal Laser Scanning and Atomic-Force Microscopy in Estimation of Elastic Properties of Organic-Rich Rocks, Bazhenov Formation, Russia.

    NASA Astrophysics Data System (ADS)

    Ahmadov, R.; Vanorio, T.; Mavko, G.

    2008-12-01

    We estimate the indentation modulus (related to Young's modulus via Poisson's ratio) of organic-rich shale samples using a nano-indentation technique based on atomic-force microscopy, coupled with scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). Our approach is based on elaboration of data from two types of microscopy (SEM and CLSM to separate organic-rich (kerogen containing) regions from the mineral matrix of oil shales, with subsequent nanoscale probing via AFM. First, the microtexture of shales is characterized by SEM. Possible regions of interest are selected, and CLSM imaging is performed to confirm the presence of organic matter. Then, an AFM-based nano- indentation probe is employed to test the hardness of the previously identified region. Finally, nano- indentation modulus values are determined for individual mineral and organic-rich phases. This allows mapping of the absolute value of the modulus, providing spatial variation of elasticity, which then can be correlated with the initial mineralogy of the sample.

  16. The time-space distribution of Eocene to Miocene magmatism in the central Peruvian polymetallic province and its metallogenetic implications

    NASA Astrophysics Data System (ADS)

    Bissig, Thomas; Ullrich, Thomas D.; Tosdal, Richard M.; Friedman, Richard; Ebert, Shane

    2008-07-01

    Eocene to late Miocene magmatism in the central Peruvian high-plain (approx. between Cerro de Pasco and Huancayo; Lats. ˜10.2-12°S) and east of the Cordillera Occidental is represented by scattered shallow-level intrusions as well as subaerial domes and volcanic deposits. These igneous rocks are calc-alkalic and range from basalt to rhyolite in composition, and many of them are spatially, temporally and, by inference, genetically associated with varied styles of major polymetallic mineralization. Forty-four new 40Ar- 39Ar and three U/Pb zircon dates are presented, many for previously undated intrusions. Our new time constraints together with data from the literature now cover most of the Cenozoic igneous rocks of this Andean segment and provide foundation for geodynamic and metallogenetic research. The oldest Cenozoic bodies are of Eocene age and include dacitic domes to the west of Cerro de Pasco with ages ranging from 38.5 to 33.5 Ma. South of the Domo de Yauli structural dome, Eocene igneous rocks occur some 15 km east of the Cordillera Occidental and include a 39.34 ± 0.28 Ma granodioritic intrusion and a 40.14 ± 0.61 Ma rhyolite sill, whereas several diorite stocks were emplaced between 36 and 33 Ma. Eocene mineralization is restricted to the Quicay high-sulfidation epithermal deposit some 10 km to the west of Cerro de Pasco. Igneous activity in the earliest Oligocene was concentrated up to 70 km east of the Cordillera Occidental and is represented by a number of granodioritic intrusions in the Milpo-Atacocha area. Relatively voluminous early Oligocene dacitic to andesitic volcanism gave rise to the Astabamba Formation to the southeast of Domo de Yauli. Some stocks at Milpo and Atacocha generated important Zn-Pb (-Ag) skarn mineralization. After about 29.3 Ma, magmatism ceased throughout the study region. Late Oligocene igneous activity was restricted to andesitic and dacitic volcanic deposits and intrusions around Uchucchacua (approx. 25 Ma) and felsic

  17. Effect of two different composts on soil quality and on the growth of various plant species in a polymetallic acidic mine soil.

    PubMed

    Rossini-Oliva, S; Mingorance, M D; Peña, A

    2017-02-01

    The effect of the addition (0-10%) of two types of sewage sludge composts (composted sewage sludge [CS] and sewage sludge co-composted with olive prune wastes [CSO]) on a polymetallic acidic soil from the Riotinto mining area was evaluated by i) a soil incubation experiment and ii) a greenhouse pot experiment using tomato (Solanum lycopersicum Mill.), ryegrass (Lolium perenne L.) and ahipa (Pachyrhizus ahipa (Wedd.) Parodi). Compost addition improved the soil organic carbon content, increased the pH and the electrical conductivity and enhanced enzyme activities and soil respiration, more for CSO than for CS. Plant growth was generally enhanced after compost addition, but not proportionally to the dose. Foliar concentrations of some hazardous elements (As, Cr, Fe) in tomato growing in non-amended soil were above the thresholds, questioning the adequacy of using this plant species. However, leaf concentrations of essential and potentially toxic elements (Fe, As, Cr and Pb) in tomato and/or ryegrass were reduced after the amendment with both composts, generally more for CSO than for CS. Conversely, foliar concentrations in ahipa, a plant species which is able to grow without the need of compost addition, were safe except for As and were only slightly affected by compost addition. This plant species would be a suitable candidate due to its low requirements and due to the limited element translocation to the leaves. Concerning the composts, amelioration of plant and soil properties was better accomplished when using CSO, a compost of sewage sludge and plant remains, than when using CS, which only contained the sludge.

  18. Evaluating Re-Os systematics in organic-rich sedimentary rocks in response to petroleum generation using hydrous pyrolysis experiments

    NASA Astrophysics Data System (ADS)

    Rooney, Alan D.; Selby, David; Lewan, Michael D.; Lillis, Paul G.; Houzay, Jean-Pierre

    2012-01-01

    Successful application of the 187Re-187Os geochronometer has enabled the determination of accurate and precise depositional ages for organic-rich sedimentary rocks (ORS) as well as establishing timing constraints of petroleum generation. However, we do not fully understand the systematics and transfer behaviour of Re and Os between ORS and petroleum products (e.g., bitumen and oil). To more fully understand the behaviour of Re-Os systematics in both source rocks and petroleum products we apply hydrous pyrolysis to two immature hydrocarbon source rocks: the Permian Phosphoria Formation (TOC = 17.4%; Type II-S kerogen) and the Jurassic Staffin Formation (TOC = 2.5%; Type III kerogen). The laboratory-based hydrous pyrolysis experiments were carried out for 72 h at 250, 300, 325 and 350 °C. These experiments provided us with whole rock, extracted rock and bitumen and in some cases expelled oil and asphaltene for evaluation of Re-Os isotopic and elemental abundance. The data from these experiments demonstrate that the majority (>95%) of Re and Os are housed within extracted rock and that thermal maturation does not result in significant transfer of Re or Os from the extracted rock into organic phases. Based on existing thermodynamic data our findings suggest that organic chelating sites have a greater affinity for the quadravalent states of Re and Os than sulphides. Across the temperature range of the hydrous pyrolysis experiments both whole rock and extracted rock 187Re/188Os ratios show small variations (3.3% and 4.7%, for Staffin, respectively and 6.3% and 4.9% for Phosphoria, respectively). Similarly, the 187Os/188Os ratios show only minor variations for the Staffin and Phosphoria whole rock and extracted rock samples (0.6% and 1.4% and 1.3% and 2.2%). These isotopic data strongly suggest that crude oil generation through hydrous pyrolysis experiments does not disturb the Re-Os systematics in ORS as supported by various studies on natural systems. The elemental

  19. Evaluating Re-Os systematics in organic-rich sedimentary rocks in response to petroleum generation using hydrous pyrolysis experiments

    USGS Publications Warehouse

    Rooney, A.D.; Selby, D.; Lewan, M.D.; Lillis, P.G.; Houzay, J.-P.

    2012-01-01

    Successful application of the 187Re–187Os geochronometer has enabled the determination of accurate and precise depositional ages for organic-rich sedimentary rocks (ORS) as well as establishing timing constraints of petroleum generation. However, we do not fully understand the systematics and transfer behaviour of Re and Os between ORS and petroleum products (e.g., bitumen and oil). To more fully understand the behaviour of Re–Os systematics in both source rocks and petroleum products we apply hydrous pyrolysis to two immature hydrocarbon source rocks: the Permian Phosphoria Formation (TOC = 17.4%; Type II-S kerogen) and the Jurassic Staffin Formation (TOC = 2.5%; Type III kerogen). The laboratory-based hydrous pyrolysis experiments were carried out for 72 h at 250, 300, 325 and 350 °C. These experiments provided us with whole rock, extracted rock and bitumen and in some cases expelled oil and asphaltene for evaluation of Re–Os isotopic and elemental abundance. The data from these experiments demonstrate that the majority (>95%) of Re and Os are housed within extracted rock and that thermal maturation does not result in significant transfer of Re or Os from the extracted rock into organic phases. Based on existing thermodynamic data our findings suggest that organic chelating sites have a greater affinity for the quadravalent states of Re and Os than sulphides. Across the temperature range of the hydrous pyrolysis experiments both whole rock and extracted rock 187Re/188Os ratios show small variations (3.3% and 4.7%, for Staffin, respectively and 6.3% and 4.9% for Phosphoria, respectively). Similarly, the 187Os/188Os ratios show only minor variations for the Staffin and Phosphoria whole rock and extracted rock samples (0.6% and 1.4% and 1.3% and 2.2%). These isotopic data strongly suggest that crude oil generation through hydrous pyrolysis experiments does not disturb the Re–Os systematics in ORS as supported by various studies on natural systems. The

  20. Oceanic response to Pliensbachian and Toarcian magmatic events: Implications from an organic-rich basinal succession in the NW Tethys

    NASA Astrophysics Data System (ADS)

    Neumeister, S.; Gratzer, R.; Algeo, T. J.; Bechtel, A.; Gawlick, H.-J.; Newton, R. J.; Sachsenhofer, R. F.

    2015-03-01

    The Bächental bituminous marls (Bächentaler Bitumenmergel) belonging to the Sachrang Member of the Lower Jurassic Middle Allgäu Formation were investigated using a multidisciplinary approach to determine environmental controls on the formation of organic-rich deposits in a semi-restricted basin of the NW Tethys during the Early Jurassic. The marls are subdivided into three units on the basis of mineralogical composition, source-rock parameters, redox conditions, salinity variations, and diagenetic processes. Redox proxies (e.g., pristane/phytane ratio; aryl isoprenoids; bioturbation; ternary plot of iron, total organic carbon, and sulphur) indicate varying suboxic to euxinic conditions during deposition of the Bächental section. Redox variations were mainly controlled by sea-level fluctuations with the tectonically complex bathymetry of the Bächental basin determining watermass exchange with the Tethys Ocean. Accordingly, strongest anoxia and highest total organic carbon content (up to 13%) occur in the middle part of the profile (upper tenuicostatum and lower falciferum zones), coincident with an increase in surface-water productivity during a period of relative sea-level lowstand that induced salinity stratification in a stagnant basin setting. This level corresponds to the time interval of the lower Toarcian oceanic anoxic event (T-OAE). However, the absence of the widely observed lower Toarcian negative carbon isotope excursion in the study section questions its unrestricted use as a global chemostratigraphic marker. Stratigraphic correlation of the thermally immature Bächental bituminous marls with the Posidonia Shale of SW Germany on the basis of C27/C29 sterane ratio profiles and ammonite data suggests that deposition of organic matter-rich sediments in isolated basins in the Alpine realm commenced earlier (late Pliensbachian margaritatus Zone) than in regionally proximal epicontinental seas (early Toarcian tenuicostatum Zone). The late Pliensbachian

  1. Towards an improved soil moisture retrieval for organic-rich soils from SMOS passive microwave L-band observations

    NASA Astrophysics Data System (ADS)

    Bircher, Simone; Richaume, Philippe; Mahmoodi, Ali; Mialon, Arnaud; Fernandez-Moran, Roberto; Wigneron, Jean-Pierre; Demontoux, François; Jonard, François; Weihermüller, Lutz; Andreasen, Mie; Rautiainen, Kimmo; Ikonen, Jaakko; Schwank, Mike; Drusch, Mattias; Kerr, Yann H.

    2017-04-01

    evaluated using the default dielectric model for mineral soils is ongoing for the "organic" L-MEB version. Additionally, in order to decide where a soil moisture retrieval using the "organic" dielectric model should be triggered, information on soil organic matter content in the soil surface layer has to be considered in the retrieval algorithm. For this purpose, SoilGrids (www.soilgrids.org) providing soil organic carbon content (SOCC) in g/kg is under study. A SOCC threshold based on the relation between the SoilGrids' SOCC and the presence of organic soil surface layers (relevant to alter the microwave L-band emissions from the land surface) in the SoilGrids' source soil profile information has to be established. In this communication, we present the current status of the above outlined studies with the objective to advance towards an improved soil moisture retrieval for organic-rich soils from SMOS passive microwave L-band observations.

  2. Rock Geochemistry and Mineralogy from Fault Zones and Polymetallic Fault Veins of the Central Front Range, Colorado

    USGS Publications Warehouse

    Caine, Jonathan S.; Bove, Dana J.

    2010-01-01

    During the 2004 to 2008 field seasons, approximately 200 hand samples of fault and polymetallic vein-related rocks were collected for geochemical and mineralogical analyses. The samples were collected by the U.S. Geological Survey as part of the Evolution of Brittle Structures Task under the Central Colorado Assessment Project (CCAP) of the Mineral Resources Program (http://minerals.cr.usgs.gov/projects/colorado_assessment/index.html). The purpose of this work has been to characterize the relation between epithermal, polymetallic mineral deposits, paleostress, and the geological structures that hosted fluid flow and localization of the deposits. The data in this report will be used to document and better understand the processes that control epithermal mineral-deposit formation by attempting to relate the geochemistry of the primary structures that hosted hydrothermal fluid flow to their heat and fluid sources. This includes processes from the scale of the structures themselves to the far field scale, inclusive of the intrusive bodies that have been thought to be the sources for the hydrothermal fluid flow. The data presented in this report are part of a larger assessment effort on public lands. The larger study area spans the region of the southern Rocky Mountains in Colorado from the Wyoming to New Mexico borders and from the eastern boundary of the Front Range to approximately the longitude of Vail and Leadville, Colorado. Although the study area has had an extensive history of geological mapping, the mapping has resulted in a number of hypotheses that are still in their infancy of being tested. For example, the proximity of polymetallic veins to intrusive bodies has been thought to reflect a genetic relation between the two features; however, this idea has not been well tested with geochemical indicators. Recent knowledge regarding the coupled nature of stress, strain, fluid flow, and geochemistry warrant new investigations and approaches to test a variety of

  3. Geochemical features of the Osovey Area, perspective for the polymetallic mineralization revealing (Polar Urals)

    NASA Astrophysics Data System (ADS)

    Savicheva, Olga; Sholokhnev, Vladimir; Makarova, Yuliya

    2014-05-01

    Osovey prospective area (184 km2) is located in the north of the Polar Urals within the Verhnekarsk Eletsk metallogenic zone, specialized on the base metals, barium and bauxite. Three structural stages, namely Riphean-Early Cambrian, the Late Carboniferous, and Triassic-Cenozoic are identified in the geological structure of the area. They are divided by the stratigraphic and angular unconformity. Volcaniclastic rocks of the Oyuyahinskaay Formation such as basaltic andesite, apovolcanogenic shales, mediosilicic and basic composition tuffs, as well as black banded shales of carbon-clay-siliceous composition related to the Silurian-Early Devonian Harotskaay Formation are predominant. Area is characterized by complex landscape conditions for the prospecting. Increased thickness of loose sediments, transeluvial weakly dissected lowlands, superaqual landscapes in lower parts of the slopes are widespread. In 2012 at the 1:50 000 scale geochemical prospecting (sampling density 500×50 m), carried out in the Osovey Area, 6000 samples were picked out from unconsolidated sediments. The samples were analyzed by the ICP MS method. Principal typomorphic elements of the polymetallic mineralization (Zn, Pb, Cu, Ag) as well as elements-indicators such as Bi, Sb, Se, Mo, etc. were defined. In addition to the polymetallic mineralization the Osoveysky area is perspective on the identification of iron-manganese ores, barites with polymetals, phosphorites, and vanadium. Such elements as Mn, P, V, U, Ba were also defined for this reason. Contrast secondary dispersion halos of Cu (up to 2060 ppm), Ag (1,45 ppm), Sb (12,3 ppm), Mo (18,9 ppm), Mn (7, 6 %), P (1,05%), Ni (338 ppm), and medium-low contrast ones of Zn, Pb, Co, V, Se, Sr, Bi, Sn, Ba, Ti, U, Cr, Zr were identified according to the results of the geochemical prospecting. Five anomalous geochemical fields (AGF) of the ore deposit rank (n ×100 km2) were identified according to the results of geochemical data processing and their

  4. Tectonic conditions of hydrothermal polymetallic vein-type mineralization, Sainte Marie-aux-Mines, France

    NASA Astrophysics Data System (ADS)

    Hafeznia, Y.; Bourlange, S.; Ohnenstetter, M.

    2012-04-01

    The Sainte-Marie-aux-Mines (SMM) mines host one of the most famous and oldest silver deposits in Europe. The SMM district is located in the central part of the Vosges mountains, France, within gneiss and granites of the Moldanubian zone. The SMM district includes the Neuenberg E-W vein-type Cu-Ag-As/Pb-Zn deposit and the Altenberg N-S vein-type Pb-Zn-Ag deposit. Deposition of the SMM hydrothermal mineralization occurred under a brittle tectonic regime that might be connected to neo-Variscan and/or post-Variscan tectonics, in a similar way as the polymetallic vein deposits of the Black Forest, Germany. A structural study was done in the Neuenberg area, in the vicinity of the Saint-Jacques vein, and within the Gabe Gottes mine, considering the orientation, extent, chronology and density of faults as well as the nature of the infilling minerals. In the Gabe-Gottes mine, the Saint-Jacques vein comprises multiple successive, sub-parallel subvertical veinlets with gangue minerals, mostly carbonates and quartz, and metal-bearing phases, sulfides and sulfosalts. The veinlets are 2 to 50 cm thick and strike N80° to N110°, the earlier veins slightly dipping towards the north, and the latest one, to the south. Seven systems of faults were identified, which may be classified into three major groups formed respectively before, during and after the main stage of ore deposition: a) Pre-mineralization faults - These consist of sinistral NE-SW strike-slip faults, and NW-SE and NE-SW steeply dipping normal faults. These could be related to Carboniferous events considering their relationships with the granitoid intrusives present in the mine area (Brézouard leucogranite ~329 Ma), and the extensional tectonics developed during exhumation processes. b) Faults associated with the main ore-deposition - These faults could be related to late-Hercynian processes from compressional to extensional tectonic regimes. Mineralization controlling faults consist of dextral and sinistral E

  5. Optimisation of sample preparation protocols for measurement of PGE and Re-Os in organic-rich shales by isotope dilution ICP-MS

    NASA Astrophysics Data System (ADS)

    Rammensee, Philipp; Aulbach, Sonja; Gudelius, Dominik; Brey, Gerhard

    2013-04-01

    Platinum-group elements (PGE) and Re-Os isotopes, which are variably redox-sensitive and fluid-soluble, have potential as proxies for the oxygenation of the atmosphere and oceans (e.g. [1]). However, analysis of these elements in organic rich shales (ORS) is challenging due to abundances of <1 ng/g and the presence of interfering isotopes or molecules of matrix elements. Furthermore, PGE-ReOs systematics in detrital and hydrogenous components may vary, and the choice of digestion parameters (reagents, temperature and pressure) during decomposition of rock powder affects the ratio of digested components [2,3]. Additional treatment to remove the matrix and pre-concentrate PGE-Re by column chromatography is necessary to minimise the effects of interfering elements, but presents its own challenges. We are in the process of conducting variations of acid digestion and column chromatographic protocols on reference sample SDO-1 (Devonian Ohio Shale, USGS). We aim to identify the optimum protocol to investigate PGE-Re-Os systematics of ORS that were sampled as part of the Barberton Drilling Project BARB5 drill core, in order to constrain the changes in detrital and hydrogenous contributions to the sediment with time, to assess the extent of euxinity in the sedimentary basin and to look for evidence of transient "whiffs of oxygen" [1]. The following digestion methods were tested: (1) 4h acid digestion in High Pressure Asher (HPA) apparatus with reverse aqua regia at 300°C and 130 bar (only this digestion allows extraction of volatilised Os in CHCl3 followed by HBr); (2) 3h reverse aqua regia digestion in centrifuge vials on hotplate at 80°C; (3) 48h reverse aqua regia digestion in closed Teflon beakers on hotplate at 140°C followed by a HF/HNO3 digestion step; (4) 48h HF/HNO3 digestion of ashed sample powder in closed Teflon beaker at 140°C on hotplate followed by an aqua regia digestion step. Column chromatographic approaches to decrease the concentrations of

  6. Fluid flow and polymetallic sulfide mineralization in the Kettara shear zone (Jebilet Massif, Variscan Belt, Morocco)

    NASA Astrophysics Data System (ADS)

    N'diaye, I.; Essaifi, A.; Dubois, M.; Lacroix, B.; Goodenough, K. M.; Maacha, L.

    2016-07-01

    The Kettara shear zone is a regional wrench shear zone within the Jebilet massif of Western Morocco, part of the Variscan orogenic belt. This massif is characterized by bimodal magmatism, largely intrusive, and by a number of polymetallic massive sulfide deposits. A syntectonic mafic-ultramafic intrusion and an adjacent, deformed pyrrhotite-rich massive sulfide deposit are located within a 'compressional jog' of the shear zone. Hydrothermal alteration in both the intrusion and the wall rocks adjacent to the deposit is characterized by syntectonic replacement processes leading to formation of chlorite-schists and quartz ± calcite veins. Fluid inclusions in mineralized (pyrrhotite-bearing) quartz veins from the wall rocks adjacent to the deposit and in veins associated with chlorite-schists within the intrusion indicate a prevalence of H2O-CO2-CH4-N2 and H2O-salt fluid systems. In the mineralized veins the fluid shows reducing conditions, with gas dominated by CH4 and N2 and salinities around 7.5 wt% NaCl, whereas in the chlorite shear zones fluid is CO2 dominated and salinities are higher than 23 wt% NaCl. Hydrogen and oxygen isotopic compositions of chlorite and quartz are similar and demonstrate involvement of metamorphic water in both the deposit and the intrusion. The data are consistent with a regional metamorphic fluid flow through the Kettara shear zone. The migrating metamorphic fluids were reduced in the organic matter-rich host rocks leading to deposition of sulfides in the mineralized veins. There are two possible hypotheses for the origin of these mineralized veins: either they were formed during deformation and remobilization of a syn-sedimentary massive sulfide deposit, or they were formed synchronously with the sulfide deposit during development of the Kettara shear zone.

  7. A Reverse Taxonomic Approach to Assess Macrofaunal Distribution Patterns in Abyssal Pacific Polymetallic Nodule Fields

    PubMed Central

    Janssen, Annika; Kaiser, Stefanie; Meißner, Karin; Brenke, Nils; Menot, Lenaick; Martínez Arbizu, Pedro

    2015-01-01

    Heightened interest in the exploitation of deep seafloor minerals is raising questions on the consequences for the resident fauna. Assessing species ranges and determination of processes underlying current species distributions are prerequisites to conservation planning and predicting faunal responses to changing environmental conditions. The abyssal central Pacific nodule belt, located between the Clarion and Clipperton Fracture Zones (CCZ), is an area prospected for mining of polymetallic nodules. We examined variations in genetic diversity and broad-scale connectivity of isopods and polychaetes across the CCZ. Faunal assemblages were studied from two mining claims (the eastern German and French license areas) located 1300 km apart and influenced by different productivity regimes. Using a reverse taxonomy approach based on DNA barcoding, we tested to what extent distance and large-scale changes in environmental parameters lead to differentiation in two macrofaunal taxa exhibiting different functions and life-history patterns. A fragment of the mitochondrial gene Cytochrome Oxidase Subunit 1 (COI) was analyzed. At a 97% threshold the molecular operational taxonomic units (MOTUs) corresponded well to morphological species. Molecular analyses indicated high local and regional diversity mostly because of large numbers of singletons in the samples. Consequently, variation in composition of genotypic clusters between sites was exceedingly large partly due to paucity of deep-sea sampling and faunal patchiness. A higher proportion of wide-ranging species in polychaetes was contrasted with mostly restricted distributions in isopods. Remarkably, several cryptic lineages appeared to be sympatric and occurred in taxa with putatively good dispersal abilities, whereas some brooding lineages revealed broad distributions across the CCZ. Geographic distance could explain variation in faunal connectivity between regions and sites to some extent, while assumed dispersal

  8. Fluid evolution in the Baia Mare epithermal gold/polymetallic district, Inner Carpathians, Romania

    NASA Astrophysics Data System (ADS)

    Grancea, Luminita; Bailly, Laurent; Leroy, Jacques; Banks, David; Marcoux, Eric; Milési, Jean; Cuney, Michel; André, Anne; Istvan, Dumitru; Fabre, Cécile

    2002-08-01

    The Baia Mare district (Romania) represents a complex segment of the Neogene/Quaternary, subduction-related, volcanic chain of the Carpathians. In this province, the calc-alkaline volcanism and associated mineralization are closely related to a major strike-slip fault and an underlying pluton. The ore deposits of the district have many features typical of low-sulfidation (or adularia-sericite) epithermal deposits. The combination of fluid-inclusion microthermometry, Raman spectroscopy, bulk crush-leach analysis, laser ablation-optical emission spectrometry (LA-OES) of individual fluid inclusions and stable isotope data has been used to characterize the ore-forming solutions involved with gold/polymetallic mineralization in three of the largest deposits. Ore fluids at Baia Sprie, Cavnic and Sasar deposits had temperatures of 320 to 150 °C and salinities in the range 0-21 wt% NaCl equiv. During phreatomagmatic activity, fracturing and periods of vein dilation, the pressure fluctuations may have caused boiling. The hydrothermal fluids were Na-K-Li-Ca chloride solutions with lesser amounts of SO4 and F. The Na/K ratios and the stable isotope compositions are consistent with equilibration of the fluids with country rocks at progressively lower temperatures. The halogen ratios (Br/Cl×103 in the range 0.13-1.21), together with sulfur isotopic systematics (δ34S=0.3-5.2 per mil), are consistent with a dominantly magmatic origin of the solutes, and probably of the ore fluids themselves.

  9. Molecular biomineralization: toward an understanding of the biogenic origin of polymetallic nodules, seamount crusts, and hydrothermal vents.

    PubMed

    Wang, Xiaohong; Wiens, Matthias; Schröder, Heinz C; Schloßmacher, Ute; Müller, Werner E G

    2011-01-01

    Polymetallic nodules and crusts, hydrothermal vents from the Deep Sea are economically interesting, since they contain alloying components, e.g., manganese or cobalt, that are used in the production of special steels; in addition, they contain rare metals applied for plasma screens, for magnets in hard disks, or in hybrid car motors. While hydrothermal vents can regenerate in weeks, polymetallic nodules and seamount crusts grow slowly. Even though the geochemical basis for the growth of the nodules and crusts has been well studied, the contribution of microorganisms to the formation of these minerals remained obscure. Recent HR-SEM (high-resolution scanning electron microscopy) analyses of nodules and crusts support their biogenic origin. Within the nodules, bacteria with surface S-layers are arranged on biofilm-like structures, around which Mn deposition starts. In crusts, coccoliths represent the dominant biologically formed structures that act as bio-seeds for an initial Mn deposition. In contrast, hydrothermal vents have apparently an abiogenic origin; however, their minerals are biogenically transformed by bacteria. In turn, strategies can now be developed for biotechnological enrichment as well as selective dissolution of metals from such concretions. We are convinced that the recent discoveries will considerably contribute to our understanding of the participation of organic matrices in the enrichment of those metals and will provide the basis for feasibility studies for biotechnological applications.

  10. Integration of multi-source and multi-scale datasets for 3D structural modeling for subsurface exploration targeting, Luanchuan Mo-polymetallic district, China

    NASA Astrophysics Data System (ADS)

    Wang, Gongwen; Ma, Zhenbo; Li, Ruixi; Song, Yaowu; Qu, Jianan; Zhang, Shouting; Yan, Changhai; Han, Jiangwei

    2017-04-01

    In this paper, multi-source (geophysical, geochemical, geological and remote sensing) datasets were used to construct multi-scale (district-, deposit-, and orebody-scale) 3D geological models and extract 3D exploration criteria for subsurface Mo-polymetallic exploration targeting in the Luanchuan district in China. The results indicate that (i) a series of region-/district-scale NW-trending thrusts controlled main Mo-polymetallic forming, and they were formed by regional Indosinian Qinling orogenic events, the secondary NW-trending district-scale folds and NE-trending faults and the intrusive stock structure are produced based on thrust structure in Caledonian-Indosinian orogenic events; they are ore-bearing zones and ore-forming structures; (ii) the NW-trending district-scale and NE-trending deposit-scale normal faults were crossed and controlled by the Jurassic granite stocks in 3D space, they are associated with the magma-skarn Mo polymetallic mineralization (the 3D buffer distance of ore-forming granite stocks is 600 m) and the NW-trending hydrothermal Pb-Zn deposits which are surrounded by the Jurassic granite stocks and constrained by NW-trending or NE-trending faults (the 3D buffer distance of ore-forming fault is 700 m); and (iii) nine Mo polymetallic and four Pb-Zn targets were identified in the subsurface of the Luanchuan district.

  11. Fluid inclusion, rare earth element geochemistry, and isotopic characteristics of the eastern ore zone of the Baiyangping polymetallic Ore district, northwestern Yunnan Province, China

    NASA Astrophysics Data System (ADS)

    Feng, Caixia; Bi, Xianwu; Liu, Shen; Hu, Ruizhong

    2014-05-01

    The Baiyangping Cu-Ag polymetallic ore district is located in the northern part of the Lanping-Simao foreland fold belt, which lies between the Jinshajiang-Ailaoshan and Lancangjiang faults in western Yunnan Province, China. The source of ore-forming fluids and materials within the eastern ore zone were investigated using fluid inclusion, rare earth element (REE), and isotopic (C, O, and S) analyses undertaken on sulfides, gangue minerals, wall rocks, and ores formed during the hydrothermal stage of mineralization. These analyses indicate: (1) The presence of five types of fluid inclusion, which contain various combinations of liquid (l) and vapor (v) phases at room temperature: (a) H2O (l), (b) H2O (l) + H2O (v), (c) H2O (v), (d) CmHn (v), and (e) H2O (l) + CO2 (l), sometimes with CO2 (v). These inclusions have salinities of 1.4-19.9 wt.% NaCl equivalents, with two modes at approximately 5-10 and 16-21 wt.% NaCl equivalent, and homogenization temperatures between 101 °C and 295 °C. Five components were identified in fluid inclusions using Raman microspectrometry: H2O, dolomite, calcite, CH4, and N2. (2) Calcite, dolomitized limestone, and dolomite contain total REE concentrations of 3.10-38.93 ppm, whereas wall rocks and ores contain REE concentrations of 1.21-196 ppm. Dolomitized limestone, dolomite, wall rock, and ore samples have similar chondrite-normalized REE patterns, with ores in the Huachangshan, Xiaquwu, and Dongzhiyan ore blocks having large negative δCe and δEu anomalies, which may be indicative of a change in redox conditions during fluid ascent, migration, and/or cooling. (3) δ34S values for sphalerite, galena, pyrite, and tetrahedrite sulfide samples range from -7.3‰ to 2.1‰, a wide range that indicates multiple sulfur sources. The basin contains numerous sources of S, and deriving S from a mixture of these sources could have yielded these near-zero values, either by mixing of S from different sources, or by changes in the geological

  12. Biogenic origin of polymetallic nodules from the Clarion-Clipperton Zone in the Eastern Pacific Ocean: electron microscopic and EDX evidence.

    PubMed

    Wang, Xiaohong; Schlossmacher, Ute; Wiens, Matthias; Schröder, Heinz C; Müller, Werner E G

    2009-01-01

    Polymetallic/ferromanganese nodules (Mn-nodules) have been assigned a huge economic potential since they contain considerable concentrations of manganese, copper, nickel, iron, and cobalt. It has been assumed that they are formed by, besides hydrogenous, nonbiogenic processes, biogenic processes based on metabolic processes driven by microorganisms. In the present study, we applied the techniques of digital optical microscopy and high-resolution scanning electron microscopy to search for microorganisms in Mn-nodules. They were collected from the Clarion-Clipperton Zone in the Eastern Pacific Ocean and are composed of Mn (23.9%), Cu (0.69%), Ni (1.02%), Fe (10.9%), and Co (0.29%). These Mn-nodules, between 2.3 and 4.8 cm, show a distinct lamination; they are composed of small-sized micronodules, 100 to 450 microm in size, which are bound together by an interstitial whitish material. In the micronodules, a dense accumulation of microorganisms/bacteria could be visualized. Only two morphotypes exist: (1) round-shaped cocci and (2) elongated rods. The cocci (diameter: approximately 3.5 microm) are arranged in bead-like chains, while the rods (approximately 2 x 0.4 microm) are arranged either as palisades or in a linear row. Energy-dispersive X-ray spectroscopy analyses showed that the areas rich in microorganisms/bacteria are also rich in Mn, while in regions where no microorganisms are found, the element Si is dominant. We suggest that growth of the Mn-nodules starts with the formation of "micronodules." The formation of micronodules is assumed to be mediated by microorganisms. After accretion of biogenic and additional nonbiogenic minerals, the micronodules assemble to large nodules on the sea floor through additional inclusion of nonbiogenic material.

  13. Severe and contrasted polymetallic contamination patterns (1900-2009) in the Loire River sediments (France).

    PubMed

    Grosbois, C; Meybeck, M; Lestel, L; Lefèvre, I; Moatar, F

    2012-10-01

    The Loire River basin (117,800 km(2), France) has been exposed to multiple sources of metals during the last 150 years, originating from major mining districts (coal and non-ferrous metals) and their associated industrial activities. Geochemical archives are established here from the analysis of a 4m sediment core in the downstream floodplain and then compared to stream bed sediments from pristine monolithological sub-basins and from bed and bank sediments in impacted tributaries. The contamination is assessed for 55 major and trace elements through their enrichment factors to Al (EF), normalized to the pre-anthropogenic background. Archives from 1900 to 2009 show enrichment (EF<1.3) not only for Ba, Be, Cs, Ga, Rb, REE, Sr, V, and Zr but also for U and Th, despite U mining activities until the 1990s. From 1900 to 1950, the level of contamination is severe for Hg, Au, Ag (10polymetallic contamination is noted for Hg (EF up to 53), Cd (23), Ag (18), Zn (6.2), Cu (6.0), Sn (5.6), Pb(4.8), Sb(4.4) and for new impacted elements as Bi (23.8), As (3.7), Cr (3.4), W (3.1), Mo (2.6), Ni (2.8), Co (1.65) due to mines, smelters, industries and from urban sewers, collected mostly after 1950 (total population of 8.4 million people). The limited dilution by detrital material (Loire sediment load about 1.5 Mt/year) is an additional cause of such severe contamination. After 1950, river eutrophication is well marked by the general increase of endogenic calcite (EF (Ca)=4), diluting all other elements by 20%. From 1980 to 2009, all contaminants, except Au (EF=100), decrease steadily.

  14. Physical, chemical and biological controls of nutrient fluxes from fine-grained, organic-rich sediments in the Indian River Lagoon, Florida

    NASA Astrophysics Data System (ADS)

    Fox, A. L.; Trefry, J. H.; Trocine, R. P.; Fox, S. L.; Yan, Y.

    2016-02-01

    Releases and biogeochemical controls of dissolved nitrogen and phosphorus from fine-grained, organic-rich sediments in the Indian River Lagoon, Florida, were determined using (1) interstitial water chemistry, (2) laboratory incubations and experiments, and (3) in situ chambers. Fluxes of nitrogen, essentially all as ammonium ions, and phosphorus, essentially all as orthophosphate ions, averaged 2000 ± 1000 and 130 ± 90 µmol/m2/day, respectively. This internal recycling of ammonium and phosphate from fine-grained, organic-rich sediments that comprise at least 10% of the sediments throughout the northern lagoon total 300 metric tons/yr and 50 metric tons/yr, respectively, and were greater than external inputs to this system. Ammonium fluxes varied spatially in response to physical and chemical differences in sediment composition. Seasonal and experimental changes in temperature resulted in a >50% differences in fluxes of ammonium and phosphate. High fluxes of dissolved sulfide supported dense mats of sulfur-oxidizing bacteria that provided stability to an otherwise unconsolidated fluff layer; this negative feedback loop reduced the net flux of nitrogen and phosphorus into the overlying water.

  15. Seasonal variations in production and consumption rates of dissolved organic carbon in an organic-rich coastal sediment

    NASA Astrophysics Data System (ADS)

    Alperin, M. J.; Albert, D. B.; Martens, C. S.

    1994-11-01

    Dissolved organic carbon (DOC) concentrations in anoxic marine sediments are controlled by at least three processes: (1) production of nonvolatile dissolved compounds, such as peptides and amino acids, soluble saccharides and fatty acids, via hydrolysis of particulate organic carbon (POC). (2) conversion of these compounds to volatile fatty acids and alcohols by fermentative bacteria. (3) consumption of volatile fatty acids and alcohols by terminal bacteria, such as sulfate reducers and methanogens. We monitored seasonal changes in concentration profiles of total DOC, nonacid-volatile (NAV) DOC and acid-volatile (AV) DOC in anoxic sediment from Cape Lookout Bight, North Carolina, USA, in order to investigate the factors that control seasonal variations in rates of hydrolysis, fermentation, and terminal metabolism. During the winter months, DOC concentrations increased continuously from 0.2 mM in the bottomwater to ~4 mM at a depth of 36 cm in the sediment column. During the summer, a large DOC maximum developed between 5 and 20 cm, with peak concentrations approaching 10 mM. The mid-depth summertime maximum was driven by increases in both NAV- and AV-DOC concentrations. Net NAV-DOC reaction rates were estimated by a diagenetic model applied to NAV-DOC concentration profiles. Depth-integrated production rates of NAV-DOC increased from February through July, suggesting that net rates of POC hydrolysis during this period are controlled by temperature. Net consumption of NAV-DOC during the late summer and early fall suggests reduced gross NAV-DOC production rates, presumably due to a decline in the availability of labile POC. A distinct subsurface peak in AV-DOC concentration developed during the late spring, when the sulfate depletion depth shoaled from 25 to 10 cm. We hypothesize that the AV-DOC maximum results from a decline in consumption by sulfate-reducing bacteria (due to sulfate limitation) and a lag in the development of an active population of methanogenic

  16. Comparison of low-cost and engineered materials for phosphorus removal from organic-rich surface water.

    PubMed

    Boyer, Treavor H; Persaud, Amar; Banerjee, Poulomi; Palomino, Pedro

    2011-10-15

    Excess phosphorus (P) in lakes and rivers remains a major water quality problem on a global scale. As a result, new materials and innovative approaches to P remediation are required. Natural materials and waste byproduct materials from industrial processes have the potential to be effective materials for P removal from surface water. Advantages of natural and waste byproduct materials include their low-cost, abundant supply, and minimal preparation, especially compared with engineered materials, such as ion exchange resins and polymeric adsorbents. As a result, natural and waste byproduct materials are commonly referred to as low-cost materials. Despite the potential advantages of low-cost materials, there are critical gaps in knowledge that are preventing their effective use. In particular, there are limited data on the performance of low-cost materials in surface waters that have high concentrations of natural organic matter (NOM), and there are no systematic studies that track the changes in water chemistry following treatment with low-cost materials or compare their performance with engineered materials. Accordingly, the goal of this work was to evaluate and compare the effectiveness of low-cost and engineered materials for P removal from NOM-rich surface water. Seven low-cost materials and three engineered materials were evaluated using jar tests and mini-column experiments. The test water was a surface water that had a total P concentration of 132-250 μg P/L and a total organic carbon concentration of 15-32 mg C/L. Alum sludge, a byproduct of drinking water treatment, and a hybrid anion exchange resin loaded with nanosize iron oxide were the best performing materials in terms of selective P removal in the presence of NOM and minimum undesirable secondary changes to the water chemistry. Copyright © 2011 Elsevier Ltd. All rights reserved.

  17. Bulk δ(15) N measurements of organic-rich rock samples by elemental analyzer/isotope ratio mass spectrometry with enhanced oxidation ability.

    PubMed

    Han, Wennian; Feng, Lianjun; Li, Hongwei; Liu, Wei

    2017-01-15

    Elemental analyzer/isotope ratio mass spectrometry (EA/IRMS) has been widely used for nitrogen isotope ratio determination in various organic and inorganic samples. However, the extent of the redox reaction in the EA reaction tube can greatly affect the accuracy and precision of measurements, especially in the case of complex geological samples. It is therefore necessary to determine the appropriate reaction conditions to reach a high recovery of nitrogen by complete combustion or thermal decomposition and quantitative reduction. The conventional Dumas dual-inlet method was used to determine the bulk nitrogen isotope composition of SGR-1 (an organic-rich standard sample), which then was analyzed by EA/IRMS under different EA reaction conditions to study the influence of the redox environment on the δ(15) N measurements. The measured data together with the results reported by previous researchers were used to evaluate the effectiveness of the nitrogen extraction for organic-rich rock samples. Our results demonstrated that with the Dumas dual-inlet method more oxidizing agent (CuO) addition to SGR-1 would yield a higher nitrogen content of 0.91% than the recommended content (0.81%) although a δ(15) N value of 17.39 ± 0.09‰ was consistent with the recommended value by USGS. Using EA/IRMS, when more O2 was injected in the reaction tube, a high nitrogen content (0.92 ± 0.01%) and a δ(15) N value (17.43 ± 0.17‰) close to that of the Dumas dual-inlet method were obtained. The addition of V2 O5 or CuO in a continuous-flow system of EA/IRMS could not effectively enable the complete combustion of SGR-1. When measuring the nitrogen isotope composition of organic-rich rock sample dominated by reduced substances with EA/IRMS, greater O2 injection will enable more complete combustion to obtain reliable nitrogen yields compared with the addition of V2 O5 or CuO. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  18. Optimized Slag Design for Maximum Metal Recovery during the Pyrometallurgical Processing of Polymetallic Deep-Sea Nodules

    NASA Astrophysics Data System (ADS)

    Friedmann, David; Friedrich, Bernd

    The steadily growing demand for critical metals and their price increase on the world market makes the mining of marine mineral resources in the not too distant future probable. Therefore, an enormous focus lays currently on the development of a viable process route to extract valuable metals from marine mineral resources such as polymetallic nodules. For a country with few natural resources like Germany, the industrial treatment of marine mineral resources could lead to a significantly decreased dependence on the global natural resource market. The focus during treatment of these nodules lies on the pyrometallurgical extraction of Ni, Cu and Co on one hand as well as the generation of a sellable ferromanganese and/or silicomanganese product on the other. All work is conducted in lab-scale SAF furnaces. The concept approach is zero-waste, which includes careful slag design, so that the produced slags adhere to environmental restrictions.

  19. Abyssal fauna of the UK-1 polymetallic nodule exploration claim, Clarion-Clipperton Zone, central Pacific Ocean: Echinodermata.

    PubMed

    Glover, Adrian G; Wiklund, Helena; Rabone, Muriel; Amon, Diva J; Smith, Craig R; O'Hara, Tim; Mah, Christopher L; Dahlgren, Thomas G

    2016-01-01

    We present data from a DNA taxonomy register of the abyssal benthic Echinodermata collected as part of the Abyssal Baseline (ABYSSLINE) environmental survey cruise 'AB01' to the UK Seabed Resources Ltd (UKSRL) polymetallic-nodule exploration claim 'UK-1' in the eastern Clarion-Clipperton Zone (CCZ), central Pacific Ocean abyssal plain. Morphological and genetic data are presented for 17 species (4 Asteroidea, 4 Crinoidea, 2 Holothuroidea and 7 Ophiuroidea) identified by a combination of morphological and genetic data. No taxa matched previously published genetic sequences, but 8 taxa could be assigned to previously-described species based on morphology, although here we have used a precautionary approach in taxon assignments to avoid over-estimating species ranges. The Clarion-Clipperton Zone is a region undergoing intense exploration for potential deep-sea mineral extraction. We present these data to facilitate future taxonomic and environmental impact study by making both data and voucher materials available through curated and accessible biological collections.

  20. Extracellular compounds produced by bacterial consortium promoting elements mobilization from polymetallic Kupferschiefer black shale (Fore-Sudetic Monocline, Poland).

    PubMed

    Włodarczyk, Agnieszka; Stasiuk, Robert; Skłodowska, Aleksandra; Matlakowska, Renata

    2015-03-01

    Culture experiments employing Fe-deficient medium showed that a consortium of indigenous microorganisms isolated from Kupferschiefer black shale produced a mixture of extracellular compounds containing siderophores which could form complexes with a wide range of elements and were able to mediate element mobilization from polymetallic black shale. The mobilization of a diverse array of elements including a number of essential trace elements (Co, Cu, Mn, Mo, Zn) and toxic species (As) was shown. Since the bacteria used in this study were originally obtained from a subsurface copper deposit, these results highlight the potential importance of extracellular compounds in biogeochemical cycles of elements in underground environment and their ecological significance in promoting the uptake of essential trace metals and resistance to toxic elements.

  1. [XRD, FTIR and XPS analysis of oxidized particles from Dongshengmiao pyrite-polymetallic sulfide deposit, inner Mongolia].

    PubMed

    Yuan, Xue-Ling; Cao, Jian-Jin; Xie, Fang-Yan; Yang, Xiao-Jie; Yan, Hong-Bin; Lai, Pei-Xin; Wang, Zheng-Hai; Zeng, Jian-Nian

    2013-01-01

    In the present paper, characteristics of material compositions, phase structures, surface element states, and transformation mechanism of oxidized particles from Dongshengmiao pyrite-polymetallic sulfide deposit were studied using modern analytical testing technology including XRD, FTIR and XPS. The results show that the samples consist of gypsum, calcite, quartz, muscovite, goethite, organic matter, etc. Primary ore in deep oxidation zone mainly under went such processes as oxidization, hydrolysis, dehydration and carbonation. Compared to the surface oxidation zone of arid and extremely arid regions in the northwestern China, the oxidation process and oxidizing condition of the deep oxidation zone were less complex. New mineral type was also not found, and extensively developed sulfate minerals were rare to be seen. The research results can not only be applied to mineral identification of oxidized particles from this type of ore deposit but also play an important role in ore exploration, mining, mineral processing, etc.

  2. Biogeochemical cycling in an organic-rich coastal marine basin: 11. The sedimentary cycling of dissolved, free amino acids

    SciTech Connect

    Burdige, D.J.; Martens, C.S. )

    1990-11-01

    In the anoxic sediments of Cape Lookout Bight, NC, concentrations of total dissolved free amino acids (TDFAAs) are highest near the sediment-water interface, and decrease to non-zero, asymptotic concentrations at depths greater than 20 cm. TDFAAs in the overlying waters are <1 {mu}M. Dissolved free amino acid (DFAA) profiles often show a secondary subsurface maximum in the region between the 1 and 5 mM sulfate isopleths. This phenomenon appears to be related to the transition in the sediments of this region from sulfate reduction to methanogenesis. A steady-state diagenetic model which quantifies the processes affecting DFAAs in these sediments yields rates of DFAA production and consumption that agree reasonably well with independent estimates of these quantities in Cape Lookout Bight and other anoxic marine sediments. The combined results of modelling pore water DFAA and sedimentary amino acid profiles indicate that significant exchange of amino acids occurs between the sediments and pore waters. These results demonstrate that the biogeochemistry of dissolved free amino acids in the pore waters of Cape Lookout Bight sediments is dominated by internal transformations (i.e. production from sedimentary amino acids, microbial remineralization, and reincorporation back into the sediments). There is some uncertainty in the magnitude of the flux of DFAAs across the sediment-water interface, although it appears to be of secondary importance when compared to the other sedimentary processes affecting DFAAs.

  3. Abyssal fauna of the UK-1 polymetallic nodule exploration area, Clarion-Clipperton Zone, central Pacific Ocean: Cnidaria.

    PubMed

    Dahlgren, Thomas G; Wiklund, Helena; Rabone, Muriel; Amon, Diva J; Ikebe, Chiho; Watling, Les; Smith, Craig R; Glover, Adrian G

    2016-01-01

    We present data from a DNA taxonomy register of the abyssal Cnidaria collected as part of the Abyssal Baseline (ABYSSLINE) environmental survey cruise 'AB01' to the UK Seabed Resources Ltd (UKSRL) polymetallic-nodule exploration area 'UK-1' in the eastern Clarion-Clipperton Zone (CCZ), central Pacific Ocean abyssal plain. This is the second paper in a series to provide regional taxonomic data for a region that is undergoing intense deep-sea mineral exploration for high-grade polymetallic nodules. Data were collected from the UK-1 exploration area following the methods described in Glover et al. (2015b). Morphological and genetic data are presented for 10 species and 18 records identified by a combination of morphological and genetic data, including molecular phylogenetic analyses. These included 2 primnoid octocorals, 2 isidid octocorals, 1 anemone, 4 hydroids (including 2 pelagic siphonophores accidentally caught) and a scyphozoan jellyfish (in the benthic stage of the life cycle). Two taxa matched previously published genetic sequences (pelagic siphonophores), two taxa matched published morphological descriptions (abyssal primnoids described from the same locality in 2015) and the remaining 6 taxa are potentially new species, for which we make the raw data, imagery and vouchers available for future taxonomic study. We have used a precautionary approach in taxon assignments to avoid over-estimating species ranges. The Clarion-Clipperton Zone is a region undergoing intense exploration for potential deep-sea mineral extraction. We present these data to facilitate future taxonomic and environmental impact study by making both data and voucher materials available through curated and accessible biological collections. For some of the specimens we also provide image data collected at the seabed by ROV, wich may facilitate more accurate taxon designation in coming ROV or AUV surveys.

  4. Abyssal fauna of the UK-1 polymetallic nodule exploration area, Clarion-Clipperton Zone, central Pacific Ocean: Cnidaria

    PubMed Central

    Wiklund, Helena; Rabone, Muriel; Amon, Diva J; Ikebe, Chiho; Watling, Les; Smith, Craig R; Glover, Adrian G

    2016-01-01

    Abstract Background We present data from a DNA taxonomy register of the abyssal Cnidaria collected as part of the Abyssal Baseline (ABYSSLINE) environmental survey cruise ‘AB01’ to the UK Seabed Resources Ltd (UKSRL) polymetallic-nodule exploration area ‘UK-1’ in the eastern Clarion-Clipperton Zone (CCZ), central Pacific Ocean abyssal plain. This is the second paper in a series to provide regional taxonomic data for a region that is undergoing intense deep-sea mineral exploration for high-grade polymetallic nodules. Data were collected from the UK-1 exploration area following the methods described in Glover et al. (2015b). New information Morphological and genetic data are presented for 10 species and 18 records identified by a combination of morphological and genetic data, including molecular phylogenetic analyses. These included 2 primnoid octocorals, 2 isidid octocorals, 1 anemone, 4 hydroids (including 2 pelagic siphonophores accidentally caught) and a scyphozoan jellyfish (in the benthic stage of the life cycle). Two taxa matched previously published genetic sequences (pelagic siphonophores), two taxa matched published morphological descriptions (abyssal primnoids described from the same locality in 2015) and the remaining 6 taxa are potentially new species, for which we make the raw data, imagery and vouchers available for future taxonomic study. We have used a precautionary approach in taxon assignments to avoid over-estimating species ranges. The Clarion-Clipperton Zone is a region undergoing intense exploration for potential deep-sea mineral extraction. We present these data to facilitate future taxonomic and environmental impact study by making both data and voucher materials available through curated and accessible biological collections. For some of the specimens we also provide image data collected at the seabed by ROV, wich may facilitate more accurate taxon designation in coming ROV or AUV surveys. PMID:27660533

  5. Magmatism and polymetallic mineralization in southwestern Qinzhou-Hangzhou metallogenic belt, South China

    NASA Astrophysics Data System (ADS)

    Huang, Xudong; Lu, Jianjun; Wang, Rucheng; Ma, Dongsheng

    2016-04-01

    As Neoproterozoic suture zone between the Yangtze Block and Cathaysia Block, Qinzhou-Hangzhou metallogenic belt is one of the 21 key metallogenic belts in China. Intensive multiple-aged felsic magmatism and related polymetallic mineralization take place in this belt. Although Neoproterozoic, Paleozoic, Triassic granites and associated deposits have been found in southwestern Qinzhou-Hangzhou metallogenic belt, Middle-Late Jurassic (150-165 Ma) magmatism and related mineralization is of the most importance. Three major kinds of Middle-Late Jurassic granitoids have been distinguished. (Cu)-Pb-Zn-bearing granitoids are slightly differentiated, calc-alkaline and metaluminous dioritic to granodioritic rocks. Sn-(W)-bearing granites contain dark microgranular enclaves and have high contents of REE and HFSE, suggesting affinities of aluminous A-type (A2) granites. W-bearing granites are highly differentiated and peraluminous rocks. (Cu)-Pb-Zn-bearing granitoids have ɛNd(t) values of -11 ˜ -4 and ɛHf(t) values of -12 ˜ -7, corresponding to TDMC(Nd) from 1.4 to 1.8 Ga and TDMC(Hf) from 1.6 to 2.0 Ga, respectively. The ɛNd(t) values of W-bearing granites vary from -11 to -8 with TDMC(Nd) of 1.6 ˜ 1.9 Ga and ɛHf(t) values change from -16 to -7 with TDMC(Hf) of 1.5 ˜ 2.0 Ga. Compared with (Cu)-Pb-Zn-bearing granitoids and W-bearing granites, the Sn-(W)-bearing granites have higher ɛNd(t) (-8 ˜ -2) and ɛHf(t) (-8 ˜ -2) values and younger TDMC(Nd) (1.1 ˜ 1.6 Ga) and TDMC(Hf) (1.2 ˜ 1.8 Ga) values, showing a more juvenile isotopic character. Sn-(W)-bearing granites originate from partial melting of granulitized lower crust involved with some mantle-derived materials. W-bearing granites are derived from partial melting of crust. (Cu)-Pb-Zn-bearing granitoids are also derived from crust but may be influenced by more mantle-derived materials. For (Cu)-Pb-Zn deposits, skarn and carbonate replacement are the most important mineralization types. Cu ore bodies mainly

  6. Microbiological and geochemical dynamics in simulated-heap leaching of a polymetallic sulfide ore.

    PubMed

    Wakeman, Kathryn; Auvinen, Hannele; Johnson, D Barrie

    2008-11-01

    The evolution of microbial populations involved in simulated-heap leaching of a polymetallic black schist sulfide ore (from the recently-commissioned Talvivaara mine, Finland) was monitored in aerated packed bed column reactors over a period of 40 weeks. The influence of ore particle size (2-6.5 mm and 6.5-12 mm) on changes in composition of the bioleaching microflora and mineral leaching dynamics in columns was investigated and compared to fine-grain (<2 microm) ore that was bioprocessed in shake flask cultures. Both column reactors and shake flasks were inoculated with 24 different species and strains of mineral-oxidizing and other acidophilic micro-organisms, and maintained at 37 degrees C. Mineral oxidation was most rapid in shake flask cultures, with about 80% of both manganese and nickel and 68% of zinc being leached within 6 weeks, though relatively little of the copper present in the ore was solubilised. The microbial consortium that emerged from the original inoculum was relatively simple in shake flasks, and was dominated by the iron-oxidizing autotroph Leptospirillum ferriphilum, with smaller numbers of Acidimicrobium ferrooxidans, Acidithiobacillus caldus and Leptospirillum ferrooxidans. Both metal recovery and (for the most part) total numbers of prokaryotes were greater in the column reactor containing the medium-grain than that containing the coarse-grain ore. The bioleaching communities in the columns displayed temporal changes in composition and differed radically from those in shake flask cultures. While iron-oxidizing chemoautotrophic bacteria were always the most numerically dominant bacteria in the medium-grain column bioreactor, there were major shifts in the most abundant species present, with the type strain of Acidithiobacillus ferrooxidans dominating in the early phase of the experiment and other bacteria (At. ferrooxidans NO37 and L. ferriphilum) dominating from week 4 to week 40. With the coarse-grain column bioreactor, similar

  7. High precision analysis modeling by backward elimination with attitude on interaction effects on Au (Ag)-polymetallic mineralization of Glojeh, Iran

    NASA Astrophysics Data System (ADS)

    Darabi-Golestan, F.; Hezarkhani, A.

    2016-12-01

    Identification of possible relationship between the elements, in mineralization and geochemical modeling is very important. The Full Cubic Model (FCM) with 90 Predictors including the main effects, quadratic terms, and interaction effects of Ag, As, Cu, Hg, Mn, Nb, P, Pb, Sn, Sr, Zn and U elements was used to create an Optimal and Reduced Cubic Model (ORCM) at vein-style Au (Ag)-polymetallic mineralization of Glojeh. It was generated with multiple regression and variance analysis and enhanced by Backward Elimination Procedure (BEP) for insignificant predictors through 15 steps. All the predictors contributed in ORCM by lowest p-value of 0.07 at degree of freedom (DF) equaled to 36. F ratio and R2 (pred.) criteria showed increasing trend from 0% to 77.80% and 6.12-262.51, respectively in model optimization. The main and interacted elements at ORCM are Sn, U, Pb, Cu and Ag × Sn, As × Mn, As × Zn, Hg × P, P × Sn, Sn2, P2, respectively based on related t-values. Interaction occurred when a pair of elements produces no similar trend on the response at different levels (associated to populations) of another element. Therefore, interaction of two elements on Au concentration was considered, simultaneously. By investigation, a disordinal interaction effect occurs on deposit for Au-As-Mn, Au-Ag-As and Au-Hg-Mn when the third element changes across the background level to vein values. Whereas, ordinal effects was observed at both population for Au-Ag-Hg and Au-As-Hg, since the lines were parallel. It implies that As has similar trend on Au for each value of Hg. The Au-Ag line explains the general downward shift by increasing Hg concentrations from vein to background. It revealed that Hg is more concentrated in background area. The accuracy and precision of this approach have been studied extensively for sample analysis, parameter identification, and modeling to ensure about BEP.

  8. When Organic-Rich Turbidites Reach 5000 m: "Cold-Seep Like" Life in the Congo Deep-Sea Fan

    NASA Astrophysics Data System (ADS)

    Pastor, L.; Toffin, L.; Cathalot, C.; Olu, K.; Brandily, C.; Bessette, S.; Lesongeur, F.; Godfroy, A.; Khripounoff, A.; Decker, C.; Taillefert, M.; Rabouille, C.

    2016-12-01

    The Congo canyon, located on the west coast of Africa, is a unique example of a canyon directly connected to a major river (The Congo River). Turbidites are responsible for a large input of terrestrial organic matter at depths up to 5000 m. These high inputs led to global high organic matter mineralization rates, with very localized hot spots that were visually observed and specifically sampled with a ROV. These hot spots, featuring substantial concentration of reduced compounds, mainly methane and sulfides, were recognizable in surface by the presence of reduced sediment patches, bacterial mats, and/or vesicomyid bivalves that host bacterial endosymbionts able to process H2S. In this paper we present geochemical sediment profiles of sulfate, methane, sulfide and dissolved iron together with phylogenetic diversity of 16S rRNA communities. This will give a first understanding of biogeochemical processes occurring in this peculiar ecosystem, mainly sulfate reduction, methanogenesis and subsequent anaerobic oxidation of methane with bacterial and archaeal assemblages similar to cold seeps environments. Iron also seems to play a major role in this system and iron/sulfur interactions as a sink for H2S can probably compete with H2S consumption by chemosynthetic bivalves, estimated at one site by vesicomyds gills incubations in a sulfide-rich solution.

  9. Physico-Chemical Heterogeneity of Organic-Rich Sediments in the Rifle Aquifer, CO: Impact on Uranium Biogeochemistry.

    PubMed

    Janot, Noémie; Lezama Pacheco, Juan S; Pham, Don Q; O'Brien, Timothy M; Hausladen, Debra; Noël, Vincent; Lallier, Florent; Maher, Kate; Fendorf, Scott; Williams, Kenneth H; Long, Philip E; Bargar, John R

    2016-01-05

    The Rifle alluvial aquifer along the Colorado River in west central Colorado contains fine-grained, diffusion-limited sediment lenses that are substantially enriched in organic carbon and sulfides, as well as uranium, from previous milling operations. These naturally reduced zones (NRZs) coincide spatially with a persistent uranium groundwater plume. There is concern that uranium release from NRZs is contributing to plume persistence or will do so in the future. To better define the physical extent, heterogeneity and biogeochemistry of these NRZs, we investigated sediment cores from five neighboring wells. The main NRZ body exhibited uranium concentrations up to 100 mg/kg U as U(IV) and contains ca. 286 g of U in total. Uranium accumulated only in areas where organic carbon and reduced sulfur (as iron sulfides) were present, emphasizing the importance of sulfate-reducing conditions to uranium retention and the essential role of organic matter. NRZs further exhibited centimeter-scale variations in both redox status and particle size. Mackinawite, greigite, pyrite and sulfate coexist in the sediments, indicating that dynamic redox cycling occurs within NRZs and that their internal portions can be seasonally oxidized. We show that oxidative U(VI) release to the aquifer has the potential to sustain a groundwater contaminant plume for centuries. NRZs, known to exist in other uranium-contaminated aquifers, may be regionally important to uranium persistence.

  10. From the Surface to the Deep-Sea: Bacterial Distributions across Polymetallic Nodule Fields in the Clarion-Clipperton Zone of the Pacific Ocean

    PubMed Central

    Lindh, Markus V.; Maillot, Brianne M.; Shulse, Christine N.; Gooday, Andrew J.; Amon, Diva J.; Smith, Craig R.; Church, Matthew J.

    2017-01-01

    Marine bacteria regulate fluxes of matter and energy essential for pelagic and benthic organisms and may also be involved in the formation and maintenance of commercially valuable abyssal polymetallic nodules. Future mining of these nodule fields is predicted to have substantial effects on biodiversity and physicochemical conditions in mined areas. Yet, the identity and distributions of bacterial populations in deep-sea sediments and associated polymetallic nodules has received relatively little attention. We examined bacterial communities using high-throughput sequencing of bacterial 16S rRNA gene fragments from samples collected in the water column, sediment, and polymetallic nodules in the Pacific Ocean (bottom depth ≥4,000 m) in the eastern Clarion-Clipperton Zone. Operational taxonomic units (OTUs; defined at 99% 16S rRNA gene identity) affiliated with JTB255 (Gammaproteobacteria) and Rhodospirillaceae (Alphaproteobacteria) had higher relative abundances in the nodule and sediment habitats compared to the water column. Rhodobiaceae family and Vibrio OTUs had higher relative abundance in nodule samples, but were less abundant in sediment and water column samples. Bacterial communities in sediments and associated with nodules were generally similar; however, 5,861 and 6,827 OTUs found in the water column were retrieved from sediment and nodule habitats, respectively. Cyanobacterial OTUs clustering among Prochlorococcus and Synechococcus were detected in both sediments and nodules, with greater representation among nodule samples. Such results suggest that vertical export of typically abundant photic-zone microbes may be an important process in delivery of water column microorganisms to abyssal habitats, potentially influencing the structure and function of communities in polymetallic nodule fields. PMID:28943866

  11. Investigation of Microbial Communities and Their Links to Biogeochemistry at the Marine Sediment-water Interface in Deep-sea Polymetallic Nodule Province

    NASA Astrophysics Data System (ADS)

    Zhou, P.; Huo, Y. Y.; Wu, Y. H.; Wang, C. S.; Xu, X. W.

    2016-12-01

    The sedimentary environment surrounding deep-sea polymetallic nodules is critical in understanding the formation of deep-sea polymetallic nodules and the connection between the biological and geological cycles of metal elements. To elucidate key microbes involved in cycling of metal elements, we particularly addressed the spatial patterns of microorganisms across scales. We collected sediments by multi-corer at ten sampling sites around Clarion-Clipperton Fracture Zone. To study the sediment-water interface, the sediments were divided into samples according to three layers of 0-5cm, 5-10cm, and 10-15cm. The metal composition in these 30 samples was investigated, such as the richness of manganese, cobalt, copper, and nickel. We found that the metals, including manganese, iron, aluminum, copper, vanadium, nickel, cobalt, even sodium, usually decreased with the increasing depth away from the sediment-water interface, while calcium usually increased. The content of calcium varied significantly in particular samples. To find the relationship between microbes and metal cycling, the biodiversity and relative abundance of taxa in the microbial communities was investigated by using culture-independent high-throughput sequencing, followed by classification and statistical analyses. Correlations among the microbes and metals were calculated, and correlation-based network was established, which helped us obtain a comprehensive understanding of relationships between metals and microorganisms. The roles of Rhizobiales and Solirubrobacterales and other microbial taxa in elementary cycling in sediments and polymetallic nodules were discussed. Here we will present our findings linking seafloor metal cycling to the diversity of deep ocean microbial community, which helps understand the biotic formation of polymetallic nodules and benefits the sustainable use and conversation of biodiversity during deep-sea mining.

  12. Palaeoredox indicators from the organic-rich Messinian early post-evaporitic deposits of the Apennines (Central Italy)

    NASA Astrophysics Data System (ADS)

    Sampalmieri, G.; Iadanza, A.; Cipollari, P.; Cosentino, D.; Lo Mastro, S.

    2009-04-01

    Bottom redox conditions in marine and lacustrine ancient basins are often inferred by the occurrence of peculiar sedimentological structures and microfaunal assemblages. The co-occurrence, in such environments, of authigenic uranium, framboidal pyrite, barite and Fe-Mn nodules and encrustations, provides a good constraint for palaeo reconstructions. Authigenic uranium is a common constituent of hydrocarbon source rocks: it forms at the sediment-water interface under oxygen-deficient conditions and accumulates together with organic matter (OM). Its precipitation is triggered by the reduction of the soluble U6+ion in seawater to insoluble U4+. With respect to black shales, uranium content has even been used to estimate the TOC. Also authigenic pyrite forms under anoxic conditions and replaces organic matter: 1) the increase in pyrite content and in organic matter are directly correlated; 2) the size distribution of framboidal pyrite (consistent with sulphate-reducing bacterial activity) is considered a measure of redox conditions within the sediment. Barite is an authigenic mineral related to Corg content, since its organic precipitation is triggered by sulphate-reduction processes occurring in decaying OM-bearing microenvironments. Finally, also Fe-Mn oxyhydroxide are typical indicators of redox conditions. About 6 My ago the Mediterranean Sea underwent a giant event of concentration referred to as Messinian Salinity Crisis, which can be roughly subdivided into an evaporitic and a post evaporitic phase. The post evaporitic phase (p-ev; 5.61-5.33 Ma) developed in a context of humid conditions and can be further distinguished into two steps: p-ev1 (early post evaporitic phase) and p-ev2 (late post evaporitic phase). Previous works focused on pev2, which is interpreted to represent the establishment of brackish water conditions (Lago-Mare biofacies). In other respects, the palaeoenvironment of p-ev1 deposits, mostly represented by resedimented evaporitic deposits or

  13. Influence of source distribution and geochemical composition of aerosols on children exposure in the large polymetallic mining region of the Bolivian Altiplano.

    PubMed

    Goix, Sylvaine; Point, David; Oliva, Priscia; Polve, Mireille; Duprey, Jean Louis; Mazurek, Hubert; Guislain, Ludivine; Huayta, Carlos; Barbieri, Flavia L; Gardon, Jacques

    2011-12-15

    The Bolivian Altiplano (Highlands) region is subject to intense mining, tailing and smelting activities since centuries because of the presence of large and unique polymetallic ore deposits (Ag, Au, Cu, Pb, Sn, Sb, Zn). A large scale PM(10), PM(2.5) aerosol monitoring survey was conducted during the dry season in one of the largest mining cities of this region (Oruro, 200,000 inhabitants). Aerosol fractions, source distribution and transport were investigated for 23 elements at approximately 1 km(2) scale resolution, and compared to children exposure data obtained within the same geographical space. As, Cd, Pb, Sb, W and Zn in aerosols are present at relatively high concentrations when compared to studies from other mining regions. Arsenic exceeds the European council PM(10) guide value (6 ng/m(3)) for 90% of the samples, topping 200 ng/m(3). Ag, As, Cd, Cu, Pb and Sb are present at significantly higher levels in the district located in the vicinity of the smelter zone. At the city level, principal component analysis combined with the mapping of factor scores allowed the identification and deconvolution of four individual sources: i) a natural magmatic source (Co, Cs, Fe, K, Mn, Na, Rb and U) originating from soil dust, resuspended by the traffic activity; ii) a natural sedimentary source (Mg, Ca, Sr, Ba and Th) resulting from the suspension of evaporative salt deposits located South; iii) an anthropogenic source specifically enriched in mined elements (As, Cd, Cu, Pb, Sb and Zn) mainly in the smelting district of the city; and iv) a Ni-Cr source homogenously distributed between the different city districts. Enrichment factors for As, Cd and Sb clearly show the impact of smelting activities, particularly in the finest PM(2.5) fraction. Comparison to children's hair metal contents collected in five schools from different districts shows a direct exposure to smelting activity fingerprinted by a unique trace elements pattern (Ag, As, Cu, Pb, Sb). Copyright © 2011

  14. The nature of porosity in organic-rich mudstones of the Upper Jurassic Kimmeridge Clay Formation, North Sea, offshore United Kingdom

    USGS Publications Warehouse

    Fishman, Neil S.; Hackley, Paul C.; Lowers, Heather; Hill, Ronald J.; Egenhoff, Sven O.; Eberl, Dennis D.; Blum, Alex E.

    2012-01-01

    Analyses of organic-rich mudstones from wells that penetrated the Upper Jurassic Kimmeridge Clay Formation, offshore United Kingdom, were performed to evaluate the nature of both organic and inorganic rock constituents and their relation to porosity in this world-class source rock. The formation is at varying levels of thermal maturity, ranging from immature in the shallowest core samples to mature in the deepest core samples. The intent of this study was to evaluate porosity as a function of both organic macerals and thermal maturity. At least four distinct types of organic macerals were observed in petrographic and SEM analyses and they all were present across the study area. The macerals include, in decreasing abundance: 1) bituminite admixed with clays; 2) elongate lamellar masses (alginite or bituminite) with small quartz, feldspar, and clay entrained within it; 3) terrestrial (vitrinite, fusinite, semifusinite) grains; and 4) Tasmanites microfossils. Although pores in all maceral types were observed on ion-milled surfaces of all samples, the pores (largely nanopores with some micropores) vary as a function of maceral type. Importantly, pores in the macerals do not vary systematically as a function of thermal maturity, insofar as organic pores are of similar size and shape in both the immature and mature Kimmeridge rocks. If any organic pores developed during the generation of hydrocarbons, they were apparently not preserved, possibly because of the highly ductile nature of much of the rock constituents of Kimmeridge mudstones (clays and organic material). Inorganic pores (largely micropores with some nanopores) have been observed in all Kimmeridge mudstones. These pores, particularly interparticle (i.e., between clay platelets), and intraparticle (i.e., in framboidal pyrite, in partially dissolved detrital K-feldspar, and in both detrital and authigenic dolomite) are noteworthy because they compose much of the observable porosity in the shales in both

  15. Minerals and clay minerals assemblages in organic-rich facies: the case study of the Sinemurian-Pliensbachian carbonate deposits of the western Lusitanian Basin (Portugal)

    NASA Astrophysics Data System (ADS)

    Caniço, Ana; Duarte, Luís V.; Silva, Ricardo L.; Rocha, Fernando; Graciano Mendonça Filho, João

    2015-04-01

    phase, and marks the disappearance of the organic-rich facies and increase of carbonate sedimentation. This enrichment was likely favored by the development of more humid conditions at the Sinemurian-Pliensbachian transition. References Duarte, L.V., Silva, R.L., Oliveira, L.C.V., Comas-Rengifo, M.J., Silva, F. 2010. Organic-rich facies in the Sinemurian and Pliensbachian of the Lusitanian Basin, Portugal: Total Organic Carbon distribution and relation to transgressive-regressive facies cycles. Geologica Acta 8, 325-340.

  16. Seismically-triggered organic-rich layers in recent sediments from Göllüköy Lake (North Anatolian Fault, Turkey)

    NASA Astrophysics Data System (ADS)

    Avşar, Ulaş; Hubert-Ferrari, Aurélia; De Batist, Marc; Lepoint, Gilles; Schmidt, Sabine; Fagel, Nathalie

    2014-11-01

    Multi-proxy analyses on the sedimentary sequence of Göllüköy Lake, which is located on the eastern North Anatolian Fault (NAF), reveals a complete and high-resolution paleoseismic record for the last 650 years. Six sedimentary events are detected in a 3.1 m-long piston core. They form distinct organic-rich intercalations within the background sedimentation, which are characterized by strong anomalies on the loss-on-ignition (LOI550) and total organic carbon (TOC) profiles, as well as by lighter colours on the X-ray radiographic images. Itrax micro-XRF core scanner data are also used to contribute to the detection and characterization of the event deposits. After the detection of the sedimentary events, their temporal correlation with the earthquakes in the historical seismicity catalogue of the NAF is tested. The youngest event is dated to 1940s by using 210Pb and 137Cs profiles in sediment, which coincides with the 1939 earthquake (Ms = 7.7) on the NAF. The ages of the older five events are determined based on radiocarbon dating and regional time-stratigraphic correlation. Radiocarbon dating on the bulk sediment samples does not provide reliable results due to hard-water effect. On the other hand, dating on charcoals, Ephippia of Daphnia and phragmite remains significantly improves the results and implies a mean sedimentation rate of 0.28 cm/yr. Based on this preliminary sedimentation rate, we show that organic matter content variations through our record correlate with the varve-based δ18O record of Nar Lake, which is located 350 km southwest of Göllüköy Lake. Accordingly, high-precipitation/low-evaporation climatic episodes detected in Nar Lake are represented by higher organic matter content in Göllüköy sediments. Fine-tuning the Göllüköy LOI550 record to the Nar δ18O record reveals that the ages of the sedimentary events in Göllüköy match with well-known historical earthquakes that occurred around the lake. Finally, the origin of the organic-rich

  17. Field transplantation of the freshwater bivalve Corbicula fluminea along a polymetallic contamination gradient (River Lot, France): 1. Geochemical characteristics of the sampling sites and cadmium and zinc bioccumulation kinetics

    SciTech Connect

    Andres, S.; Baudrimont, M.; Lapaquellerie, Y.; Ribeyre, F.; Maillet, N.; Latouche, C.; Boudou, A.

    1999-11-01

    Specimens of the Asiatic clam Corbicula fluminea were transplanted from a clean lacustrine site to four stations along a polymetallic gradient in the river Lot (France), downstream from an old Zn ore treatment facility. The bivalves were held in benthic cages for a 5-month exposure period, April to September 1996; mollusk growth and metal bioaccumulation kinetics (Cd, Zn) were followed by subsampling the cages at t = 0, 21, 49, 85, 120, and 150 d. Rates of Cd bioaccumulation in the whole soft bodies and in individual organs were greater at the upstream stations located close to the pollution source, but there was no direct proportionality between Cd in the bivalves and in the unfiltered or filtered river water samples. Unlike the case for Cd, rates of Zn bioaccumulation did not reflect the contamination gradient. Marked growth differences were measured among the four stations, reflecting both nutritional differences and changes in the degree of metal contamination; these growth differences produced markedly different trends when metal bioaccumulation was expressed in terms of burdens rather than concentrations.

  18. Scientific Challenges of Producing Natural Gas from Organic-Rich Shales - From the Nano-Scale to the Reservoir Scale (Louis Néel Medal Lecture)

    NASA Astrophysics Data System (ADS)

    Zoback, Mark D.

    2013-04-01

    In this talk I will discuss several on-going research projects with the PhD students and post-Docs in my group that are investigating the wide variety of factors affecting the success of stimulating gas production from extremely low permeability organic-rich shales. First, I will present laboratory measurements of pore structure, adsorption and nano-scale fluid transport on samples of the Barnett, Eagle Ford, Haynesville, Marcellus and Horn River shale (all in North America). I will also discuss how these factors affect ultimate gas recovery. Second, I present several lines of evidence that indicate that during hydraulic fracturing stimulation of shale gas reservoirs there is pervasive slow slip occurring on pre-existing fractures and faults that are not detected by standard microseismic monitoring. I will also present laboratory and modeling studies that demonstrate why slowly slipping faults are to be expected. In many cases, slow slip on faults may be the most important process responsible for stimulating gas production in the reservoirs. Finally, I discuss our research on the viscoplastic behavior of the shales and what viscoplasticity implies for the evolution of the physical properties of the reservoir and in situ stress magnitudes.

  19. New Re-Os organic-rich shale and sulphide geochronology data from the Pre-Sturtian Chuar Group, Grand Canyon

    NASA Astrophysics Data System (ADS)

    Rooney, Alan; Austermann, Jaqueline; Selby, David; Dehler, Carol; Karlstrom, Karl; Macdonald, Francis

    2016-04-01

    The Neoproterozoic Chuar Group is an exceptionally well-exposed and unmetamorphosed succession of siliciclastics and carbonates with a thickness of ~1600 m. Deposition of the Chuar Group began ~782 Ma and ended 742 ± 6 Ma (U-Pb detrital zircon data and U-Pb reworked tuff age, respectively). The Chuar Group hosts an assemblage of diverse microfossils including vase-shaped microfossils and records major perturbations to biogeochemical cycles. Here we present new Re-Os geochronology data from organic-rich shale and from sulphide (marcasite) that further constrain the duration and depositional history of this pre-Sturtian succession and enhances global correlation with other Neoproterozoic sedimentary successions. In addition to the new geochronology data, we also present a more complete statistical analysis of uncertainties in the Re-Os shale geochronometer in an effort to quantify the different contributors to age uncertainties and identify opportunities to reduce them. This will help to further integration of Re-Os into the EARTHTIME initiative.

  20. Reactivity of organic-rich sediment in sea water at 350/sup 0/C, 500 bars: experimental and theoretical constraints and implications for the Guaymas basin hydrothermal system

    SciTech Connect

    Thornton, E.C.; Seyfried, W.E. Jr.

    1987-07-01

    Hydrothermal alteration of organic-rich diatomaceous sediment by sea water was modeled experimentally at 350/sup 0/C, 500 bars, and sea water/sediment mass ratio of 3. The experiment was performed to assess the effect of organic matter reactivity on solution speciation and sediment alteration processes at an elevated temperature and pressure, and provide requisite data to better understand the chemistry of hydrothermal fluids issuing from vents in the Guaymas Basin, Gulf of California. Sea water chemistry changed greatly during the experiment. Moreover, owing to the thermal alteration of sediment organic matter, organic acids, phenolic derivatives and phthlate were released to solution. Examination of solid alteration products revealed the effects of extensive dissolution and precipitation processes characterized by total elimination of diatoms and formation of cristobalite, quartz, pyrite, pyrrhotite, mixed layer chlorite/smectite, and calcite. A graphitic residue was also present in the products of the experiment. Mg and Na fixation reactions during the experiment generated significant H/sup +/, although the pH measured at 25/sup 0/C was approximately 6.2. Speciation calculations including ammine and acetate protonation reactions give a pH at experimental conditions of approximately 5.1, while mineral solubility relations involving virtually all alteration phases require a pH of 5.57 to 5.94. A near neutral pH at experimental conditions constrains the mobility of Fe, Mn, Zn, Cu and Ni, which existed in solution as chloro-complexes.

  1. Marine redox stratification during the early Cambrian (ca. 529-509 Ma) and its control on the development of organic-rich shales in Yangtze Platform

    NASA Astrophysics Data System (ADS)

    Zhang, Yuying; He, Zhiliang; Jiang, Shu; Gao, Bo; Liu, Zhongbao; Han, Bo; Wang, Hu

    2017-06-01

    High resolution geochemical data from nine sections representing shelf to basinal environments in the Yangtze Platform were analyzed to reconstruct the marine redox environment during early Cambrian. Based on Fe species and Mo/TOC ratios, we have supplemented marine redox stratification during Stage 4 (late Canglangpuian-Longwangmiaoan, ˜514-509 Ma) on basis of the previously studied Stage 2-Stage 3 (Meishucunian-Qiongzhusian, ˜529-514 Ma). A new proposed marine stratified redox model indicates that the middepth "euxinic wedge" developed at the base of slope during ˜514-509 Ma in contrast to that the "euxinic wedge" prevailed at the shelf margin during ˜529-514 Ma, even though these middepth euxinic waters both occurred between the oxic surface waters and ferruginous deep waters. This marine redox stratification resulted in high production and good preservation of organic matter during early Cambrian. TOC values in euxinic waters in the middle are generally higher than in ferruginous waters due to upwelling in slope. Therefore, the lower Cambrian organic-rich shales in the Yangtze Platform are inferred to be deposited under the anoxic-ferruginous and euxinic bottom waters with moderate-strong restriction.

  2. Distinctive Reactivities at Biotite Edge and Basal Planes in the Presence of Organic Ligands: Implications for Organic-Rich Geologic CO2 Sequestration.

    PubMed

    Zhang, Lijie; Jun, Young-Shin

    2015-08-18

    To better understand how scCO2-saturated brine-mineral interactions can affect safe and efficient geologic CO2 sequestration (GCS), we studied the effects of organic ligands (acetate and oxalate) on biotite dissolution and surface morphological changes. The experimental conditions were chosen to be relevant to GCS sites (95 °C and 102 atm CO2). Quantitative analyses of dissolution differences between biotite edge and basal planes were made. Acetate slightly inhibited biotite dissolution and promoted secondary precipitation. The effect of acetate was mainly pH-induced aqueous acetate speciation and the subsequent surface adsorption. Under the experimental conditions, most of acetate exists as acetic acid and adsorbs to biotite surface Si and Al sites, thereby reducing their release. However, oxalate strongly enhanced biotite dissolution and induced faster and more significant surface morphology changes by forming bidentate mononuclear surface complexes. For the first time, we show that oxalate selectively attacks edge surface sites and enhances biotite dissolution. Thus, oxalate increases the relative reactivity ratio of biotite edge surfaces to basal surfaces, while acetate does not impact this relative reactivity. This study provides new information on reactivity differences at biotite edge and basal planes in the presence of organic ligands, which has implications for safe CO2 storage in organic-rich sites.

  3. Abyssal near-bottom dispersal stages of benthic invertebrates in the Clarion-Clipperton polymetallic nodule province

    NASA Astrophysics Data System (ADS)

    Kersten, Oliver; Smith, Craig R.; Vetter, Eric W.

    2017-09-01

    Growing interest in polymetallic nodule mining has intensified the need to characterize the abundance, community structure and vertical flux of meroplankton in the Clarion-Clipperton Zone (CCZ) to facilitate the estimation of larval supply and potential connectivity of benthic populations. These ecological parameters are essential to predict recolonization processes following the expected large-scale, high intensity disturbances associated with nodule extraction. Here, we present the first description of the composition, abundance, temporal variability, and mesoscale distribution of dispersing stages of the benthos in two study areas in the eastern CCZ. Samples from free-vehicle plankton pumps showed little variation in meroplankton diversity and abundance over scales of 30-100 km for time scales of days to weeks. However, sediment-trap samples revealed high temporal variability in vertical flux over weeks to months. Larval abundances and fluxes measured in the abyssal CCZ are 1-2 orders of magnitude lower than observed at deep-sea ridge and hydrothermal-vent habitats. We found significantly higher downward larval fluxes at 11 m above the bottom (mab) than at 146 mab, indicating accumulation or retention of meroplankton within the Benthic Boundary Layer (BBL). The high abundance of meroplankton in the BBL emphasizes its importance to dispersing stages and suggests that the creation of large sediment plumes in the BBL during nodule mining could compromise the dispersal and recruitment abilities of the abyssal benthos, potentially slowing rates and altering patterns of benthic community recovery following mining disturbance.

  4. Novel benthic foraminifera are abundant and diverse in an area of the abyssal equatorial Pacific licensed for polymetallic nodule exploration

    NASA Astrophysics Data System (ADS)

    Goineau, Aurélie; Gooday, Andrew J.

    2017-04-01

    The benthic biota of the Clarion-Clipperton Zone (CCZ, abyssal eastern equatorial Pacific) is the focus of a major research effort linked to possible future mining of polymetallic nodules. Within the framework of ABYSSLINE, a biological baseline study conducted on behalf of Seabed Resources Development Ltd. in the UK-1 exploration contract area (eastern CCZ, ~4,080 m water depth), we analysed foraminifera (testate protists), including ‘live’ (Rose Bengal stained) and dead tests, in 5 cores (0-1 cm layer, >150-μm fraction) recovered during separate megacorer deployments inside a 30 by 30 km seafloor area. In both categories (live and dead) we distinguished between complete and fragmented specimens. The outstanding feature of these assemblages is the overwhelming predominance of monothalamids, a group often ignored in foraminiferal studies. These single-chambered foraminifera, which include agglutinated tubes, spheres and komokiaceans, represented 79% of 3,607 complete tests, 98% of 1,798 fragments and 76% of the 416 morphospecies (live and dead combined) in our samples. Only 3.1% of monothalamid species and 9.8% of all species in the UK-1 assemblages are scientifically described and many are rare (29% singletons). Our results emphasise how little is known about foraminifera in abyssal areas that may experience major impacts from future mining activities.

  5. Abyssal fauna of the UK-1 polymetallic nodule exploration claim, Clarion-Clipperton Zone, central Pacific Ocean: Echinodermata

    PubMed Central

    Glover, Adrian G; Wiklund, Helena; Rabone, Muriel; Amon, Diva J; Smith, Craig R; O'Hara, Tim; Mah, Christopher L

    2016-01-01

    Abstract We present data from a DNA taxonomy register of the abyssal benthic Echinodermata collected as part of the Abyssal Baseline (ABYSSLINE) environmental survey cruise ‘AB01’ to the UK Seabed Resources Ltd (UKSRL) polymetallic-nodule exploration claim ‘UK-1’ in the eastern Clarion-Clipperton Zone (CCZ), central Pacific Ocean abyssal plain. Morphological and genetic data are presented for 17 species (4 Asteroidea, 4 Crinoidea, 2 Holothuroidea and 7 Ophiuroidea) identified by a combination of morphological and genetic data. No taxa matched previously published genetic sequences, but 8 taxa could be assigned to previously-described species based on morphology, although here we have used a precautionary approach in taxon assignments to avoid over-estimating species ranges. The Clarion-Clipperton Zone is a region undergoing intense exploration for potential deep-sea mineral extraction. We present these data to facilitate future taxonomic and environmental impact study by making both data and voucher materials available through curated and accessible biological collections. PMID:26929713

  6. Novel benthic foraminifera are abundant and diverse in an area of the abyssal equatorial Pacific licensed for polymetallic nodule exploration

    PubMed Central

    Goineau, Aurélie; Gooday, Andrew J.

    2017-01-01

    The benthic biota of the Clarion–Clipperton Zone (CCZ, abyssal eastern equatorial Pacific) is the focus of a major research effort linked to possible future mining of polymetallic nodules. Within the framework of ABYSSLINE, a biological baseline study conducted on behalf of Seabed Resources Development Ltd. in the UK-1 exploration contract area (eastern CCZ, ~4,080 m water depth), we analysed foraminifera (testate protists), including ‘live’ (Rose Bengal stained) and dead tests, in 5 cores (0–1 cm layer, >150-μm fraction) recovered during separate megacorer deployments inside a 30 by 30 km seafloor area. In both categories (live and dead) we distinguished between complete and fragmented specimens. The outstanding feature of these assemblages is the overwhelming predominance of monothalamids, a group often ignored in foraminiferal studies. These single-chambered foraminifera, which include agglutinated tubes, spheres and komokiaceans, represented 79% of 3,607 complete tests, 98% of 1,798 fragments and 76% of the 416 morphospecies (live and dead combined) in our samples. Only 3.1% of monothalamid species and 9.8% of all species in the UK-1 assemblages are scientifically described and many are rare (29% singletons). Our results emphasise how little is known about foraminifera in abyssal areas that may experience major impacts from future mining activities. PMID:28382941

  7. In-situ high temperature X-ray diffraction study on the phase transition process of polymetallic sulfide ore

    NASA Astrophysics Data System (ADS)

    Li, Guangshi; Cheng, Hongwei; Xiong, Xiaolu; Lu, Xionggang; Xu, Cong; Lu, Changyuan; Zou, Xingli; Xu, Qian

    2017-04-01

    The phase transformation of the polymetallic sulfide ore is quite complicated, especially the variety and diversity of the roasted intermediate. The mineralogy properties of the ore particles were characterized by XRF, ICP and SEM-EDS. The thermal stability of the complex ore was investigated using TG-DSC under different atmosphere (pure N2 and 1% O2-N2). The phase changes and intermediates were revealed by the in-situ XRD in pure N2 and 1% O2-N2 atmospheres with the temperature range from 25 to 800°C. These results indicated that the crystal transformation of the pyrrhotite from monoclinic to hexagonal at 320°C, and the pentlandite and chalcopyrite were decomposed into monosulfide solid solution in pure N2. While the pentlandite and chalcopyrite were completely oxidized into M*xFe3-xO4 (M*=Fe, Ni, Cu) and Fe2O3, which is also the final product of the ore sample oxidized under 1% O2-N2 atmosphere.

  8. Geochemistry and Re-Os geochronology of the organic-rich sedimentary rocks in the Jingtieshan Fe-Cu deposit, North Qilian Mountains, NW China

    NASA Astrophysics Data System (ADS)

    Yang, Xiuqing; Zhang, Zuoheng; Li, Chao; Duan, Shigang; Jiang, Zongsheng

    2016-04-01

    The Jingtieshan Group in the North Qilian Mountains, NW China, is dominantly composed of banded iron formations (BIFs), copper deposits and organic-rich sedimentary rocks (ORS, carbonaceous phyllite). X-ray diffraction analysis of the ORS shows the mineral assemblage to be quartz + clay minerals. The total organic carbon contents show a range of 0.44-1.72%. Here we present the results of the geochemistry and Re-Os geochronology of the ORS from the Jingtieshan Group. The high values of Chemical Index of Alteration (CIA), Chemical Index of Weathering (CIW), Plagioclase Index of Alteration (PIA), and Th/U ratio, indicate intense weathering. The Al2O3/TiO2, Zr/Sc, Th/Sc, La/Th ratios, high rare earth elements abundances, light rare earth elements enrichment (normalized to chondrite), and distinctly negative Eu anomalies, suggest that the Jingtieshan Group ORS were derived mainly from felsic volcanic units. The new Re-Os isochron age of 1308 ± 100 Ma (2σ, n = 6, MSWD = 23) broadly overlap with the previous published ages determined using Sm-Nd and U-Pb isotope systems. The new age represents the depositional age of the Jingtieshan Group, as well that of BIF in the Jingtieshan area. Furthermore, the initial 187Os/188Os ratios (0.44 ± 0.07) indicate that the Os in the seawater was dominantly derived from hydrothermal fluids (∼75%). The Ce anomaly (Ce/Ce∗ = 0.95-1.00) and V/(V + Ni) ratios (0.71-0.86), as well as the lack of enrichment in redox-sensitive trace elements such as U, V, Zn, Pb, Cu, Ni, Cr, Co and Mn, together with the presence of overlying BIF, suggest that the Jingtieshan area represents a ferruginous deep-water succession. This, and intense submarine hydrothermal activities contributed to the deposition of the Jingtieshan BIF.

  9. Changes in abundance and community structure of nematodes from the abyssal polymetallic nodule field, Tropical Northeast Pacific

    NASA Astrophysics Data System (ADS)

    Miljutin, Dmitry; Miljutina, Maria; Messié, Monique

    2015-12-01

    Deep-sea fields of polymetallic nodules in the Clarion-Clipperton Zone (CCFZ, tropical NE Pacific) are currently being investigated to assess their potential for commercial mining. During such mining, benthic communities will be inevitably disturbed or destroyed. Therefore, assessments of their standing stock and composition may be helpful for the future evaluation of possible impacts of commercial nodule exploitation. Analysis of nematode communities (at genus level) inhabiting the French license area of the CCFZ were studied based on data from the cruises NODINAUT (2004) and BIONOD (2012). The total nematode density was ca. 1.5-fold higher in 2012 as compared with 2004. This reflected a 2-2.5 times higher density of non-selective deposit-feeders (i.e. possessing a small buccal cavity without armature) in 2012 compared with 2004, whereas no significant differences between sampling periods were observed in the density of the other feeding groups. Consequently, whilst the list of the most abundant genera was identical, their relative abundances changed significantly. The relative abundance of the genus Thalassomonhystera was two times greater in 2012 than in 2004, whereas the relative abundances of the genera Acantholaimus and Theristus were significantly lower in 2012 (10% and 4%, respectively) than in 2004 (28% and 9%). Nematode diversity (including values of diversity indices and total number of recorded genera) was significantly lower in 2012 in comparison with 2004. Although our data do not take into account seasonal and shorter temporal scales of variability in nematode assemblages, we report here that a certain fraction of variations observed between the two sampling periods could be associated with differences in primary production. Future studies should aim to better characterise temporal variability in nematode communities of the CCFZ at seasonal and interannual scales.

  10. Geochemistry and petrology of the indium-bearing polymetallic skarn ores at Pitkäranta, Ladoga Karelia, Russia

    NASA Astrophysics Data System (ADS)

    Valkama, M.; Sundblad, K.; Cook, N. J.; Ivashchenko, V. I.

    2016-08-01

    The historic mining district of Pitkäranta in the Ladoga region, Fennoscandian Shield, was exploited for Fe, Cu, Zn, Pb, Sn and Ag in the nineteenth to twentieth centuries. The Pitkäranta region is dominated by Palaeoproterozoic supracrustal rocks, which, together with gneissic Archaean dome structures, constitute an allochthonous terrane complex that amalgamated to the Archaean continent during the Svecokarelian orogeny at 1.9-1.8 Ga. This crustal complex was intruded by 1.8 Ga Late orogenic granites, 1.54 Ga anorogenic rapakivi granites and 1.45 Ga dolerites. The polymetallic skarn ores of Pitkäranta extend over a 25-km-long zone in Palaeoproterozoic supracrustal rocks and formed from hydrothermal solutions, which emanated from the anorogenic rapakivi granites and reacted with marble layers. Four major ore types are recognised after the dominating metal: Fe, Cu, Sn and Zn, respectively. These types are not restricted to individual mines or mine fields but represent end members in zonation patterns within each ore body. Pitkäranta was the second discovery site in the world for indium but has been without modern documentation for more than 75 years. The indium contents in the ores are up to 600 ppm, in most cases sphalerite-hosted. The only roquesite-bearing sample in this study had an indium grade of 291 ppm and an In/Zn ratio of 51 (close to the criteria for the limiting conditions for creating an In-rich mineral). The Pitkäranta ores have a potential for future small-scale exploitation, but all such plans are hampered by high contents if Bi, Cd and As.

  11. Effect of thermal maturation on the K-Ar, Rb-Sr and REE systematics of an organic-rich New Albany Shale as determined by hydrous pyrolysis

    USGS Publications Warehouse

    Clauer, Norbert; Chaudhuri, Sambhudas; Lewan, M.D.; Toulkeridis, T.

    2006-01-01

    Hydrous-pyrolysis experiments were conducted on an organic-rich Devonian-Mississippian shale, which was also leached by dilute HCl before and after pyrolysis, to identify and quantify the induced chemical and isotopic changes in the rock. The experiments significantly affect the organic-mineral organization, which plays an important role in natural interactions during diagenetic hydrocarbon maturation in source rocks. They produce 10.5% of volatiles and the amount of HCl leachables almost doubles from about 6% to 11%. The Rb-Sr and K-Ar data are significantly modified, but not just by removal of radiogenic 40Ar and 87Sr, as described in many studies of natural samples at similar thermal and hydrous conditions. The determining reactions relate to alteration of the organic matter marked by a significant change in the heavy REEs in the HCl leachate after pyrolysis, underlining the potential effects of acidic fluids in natural environments. Pyrolysis induces also release from organics of some Sr with a very low 87Sr/86Sr ratio, as well as part of U. Both seem to have been volatilised during the experiment, whereas other metals such as Pb, Th and part of U appear to have been transferred from soluble phases into stable (silicate?) components. Increase of the K2O and radiogenic 40Ar contents of the silicate minerals after pyrolysis is explained by removal of other elements that could only be volatilised, as the system remains strictly closed during the experiment. The observed increase in radiogenic 40Ar implies that it was not preferentially released as a volatile gas phase when escaping the altered mineral phases. It had to be re-incorporated into newly-formed soluble phases, which is opposite to the general knowledge about the behavior of Ar in supergene natural environments. Because of the strictly closed-system conditions, hydrous-pyrolysis experiments allow to better identify and even quantify the geochemical aspects of organic-inorganic interactions, such as

  12. [Dust and gas factors in extraction of polymetallic ore in Arctic conditions and their hygienic assessment].

    PubMed

    Borisenkova, R V; Lutsenko, L A; Skriabin, S Iu; Khristenko, P P

    1996-01-01

    Studies of drilling and blasting method of copper and nickel ores extraction at underground Transpolar mines proved that the highest concentrations of dust appeared during dry drilling of vertical blast holes, work of scraper windlass, fragmentation of out-size blocks, preparation of concrete mixture. Presence of aggressive metals, especially nickel, in the ore dust is a main base for planned thorough investigations of fibrogenic, toxic and carcinogenic effects of copper and nickel ore dust, for more precise assessment of its MAC in the air of workplace. Two-step purification of exhaust gases appearing due to mining diesel machines is not quite efficient, as the concentrations of nitrogen oxides (assessed through nitrogen dioxide) continually exceeded the MAC.

  13. Insights into the abundance and diversity of abyssal megafauna in a polymetallic-nodule region in the eastern Clarion-Clipperton Zone

    PubMed Central

    Amon, Diva J.; Ziegler, Amanda F.; Dahlgren, Thomas G.; Glover, Adrian G.; Goineau, Aurélie; Gooday, Andrew J.; Wiklund, Helena; Smith, Craig R.

    2016-01-01

    There is growing interest in mining polymetallic nodules in the abyssal Clarion-Clipperton Zone (CCZ) in the Pacific. Nonetheless, benthic communities in this region remain poorly known. The ABYSSLINE Project is conducting benthic biological baseline surveys for the UK Seabed Resources Ltd. exploration contract area (UK-1) in the CCZ. Using a Remotely Operated Vehicle, we surveyed megafauna at four sites within a 900 km2 stratum in the UK-1 contract area, and at a site ~250 km east of the UK-1 area, allowing us to make the first estimates of abundance and diversity. We distinguished 170 morphotypes within the UK-1 contract area but species-richness estimators suggest this could be as high as 229. Megafaunal abundance averaged 1.48 ind. m−2. Seven of 12 collected metazoan species were new to science, and four belonged to new genera. Approximately half of the morphotypes occurred only on polymetallic nodules. There were weak, but statistically significant, positive correlations between megafaunal and nodule abundance. Eastern-CCZ megafaunal diversity is high relative to two abyssal datasets from other regions, however comparisons with CCZ and DISCOL datasets are problematic given the lack of standardised methods and taxonomy. We postulate that CCZ megafaunal diversity is driven in part by habitat heterogeneity. PMID:27470484

  14. Insights into the abundance and diversity of abyssal megafauna in a polymetallic-nodule region in the eastern Clarion-Clipperton Zone

    NASA Astrophysics Data System (ADS)

    Amon, Diva J.; Ziegler, Amanda F.; Dahlgren, Thomas G.; Glover, Adrian G.; Goineau, Aurélie; Gooday, Andrew J.; Wiklund, Helena; Smith, Craig R.

    2016-07-01

    There is growing interest in mining polymetallic nodules in the abyssal Clarion-Clipperton Zone (CCZ) in the Pacific. Nonetheless, benthic communities in this region remain poorly known. The ABYSSLINE Project is conducting benthic biological baseline surveys for the UK Seabed Resources Ltd. exploration contract area (UK-1) in the CCZ. Using a Remotely Operated Vehicle, we surveyed megafauna at four sites within a 900 km2 stratum in the UK-1 contract area, and at a site ~250 km east of the UK-1 area, allowing us to make the first estimates of abundance and diversity. We distinguished 170 morphotypes within the UK-1 contract area but species-richness estimators suggest this could be as high as 229. Megafaunal abundance averaged 1.48 ind. m-2. Seven of 12 collected metazoan species were new to science, and four belonged to new genera. Approximately half of the morphotypes occurred only on polymetallic nodules. There were weak, but statistically significant, positive correlations between megafaunal and nodule abundance. Eastern-CCZ megafaunal diversity is high relative to two abyssal datasets from other regions, however comparisons with CCZ and DISCOL datasets are problematic given the lack of standardised methods and taxonomy. We postulate that CCZ megafaunal diversity is driven in part by habitat heterogeneity.

  15. Mineral potential tracts for polymetallic Pb-Zn-Cu vein deposits (phase V, deliverable 71): Chapter I in Second projet de renforcement institutionnel du secteur minier de la République Islamique de Mauritanie (PRISM-II)

    USGS Publications Warehouse

    Beaudoin, Georges

    2015-01-01

    In Mauritania, mineral occurrences of the polymetallic Pb-Zn-Cu vein deposit type are found near the Florence-El Khdar shear zone in northeast Mauritania. The deposits visited were deemed representative of other similar occurrences and consist of quartz veins with trace sulfides. The low sulfide and Pb-Zn-Cu content in the quartz veins is unlike producing polymetallic Pb-Zn-Cu vein deposits, such that the veins are not considered to belong to this deposit type. Mineral potential tracts for polymetallic Pb-ZnCu veins are highly speculative considering the lack of known mineralization belonging to this deposit type. Mineral potential tracts for polymetallic Pb-Zn-Cu veins are associated with and surround major shear zones in the Rgueïbat Shield and zones of complex faulting in the southern Mauritanides, at the exclusion of the imbricated thrust faults that are not considered favorable for this deposit type. No skarn and replacement deposits have been documented in Mauritania and the low mineral potential is indicated by lack of causative Mesozoic and Cenozoic mafic to felsic stocks.

  16. Linear polynuclear helicates as a link between discrete supramolecular complexes and programmed infinite polymetallic chains.

    PubMed

    Dalla-Favera, Natalia; Hamacek, Josef; Borkovec, Michal; Jeannerat, Damien; Gumy, Frédéric; Bünzli, Jean-Claude G; Ercolani, Gianfranco; Piguet, Claude

    2008-01-01

    The contribution of the solvation energies to the assembly of polynuclear helicates reduces the free energy of intermetallic repulsion, DeltaE(MM), in condensed phase to such an extent that stable D(3)-symmetrical tetranuclear lanthanide-containing triple-stranded helicates [Ln(4)(L4)(3)](12+) are quantitatively produced at millimolar concentrations, despite the twelve positive charge borne by these complexes. A detailed modelling of the formation constants using statistical factors, adapted to self-assembly processes involving intra- and intermolecular connections, provides a set of five microscopic parameters, which can be successfully used for rationalizing the stepwise generation of linear bi-, tri- and tetranuclear analogues. Photophysical studies of [Eu(4)(L4)(3)](12+) confirm the existence of two different binding sites producing differentiated metal-centred emission at low temperature, which transforms into single site luminescence at room temperature because of intramolecular energy funelling processes.

  17. A 4D Synchrotron X-Ray-Tomography Study of the Formation of Hydrocarbon- Migration Pathways in Heated Organic-Rich Shale

    SciTech Connect

    Panahi, Hamed; Meakin, Paul; Renard, Francois; Kobchenko, Maya; Scheibert, Julien; Mazzini, Adriano; Jamtveit, Bjorn; Malthe-Sorenssen, Anders; Dysthe, Dag Kristian

    2012-11-27

    Recovery of oil from oil shales and the natural primary migration of hydrocarbons are closely related processes that have received renewed interest in recent years because of the ever tightening supply of conventional hydrocarbons and the growing production of hydrocarbons from low-permeability tight rocks. Quantitative models for conversion of kerogen into oil and gas and the timing of hydrocarbon generation have been well documented. However, lack of consensus about the kinetics of hydrocarbon formation in source rocks, expulsion timing, and how the resulting hydrocarbons escape from or are retained in the source rocks motivates further investigation. In particular, many mechanisms have been proposed for the transport of hydrocarbons from the rocks in which they are generated into adjacent rocks with higher permeabilities and smaller capillary entry pressures, and a better understanding of this complex process (primary migration) is needed. To characterize these processes, it is imperative to use the latest technological advances. In this study, it is shown how insights into hydrocarbon migration in source rocks can be obtained by using sequential high-resolution synchrotron X-ray tomography. Three-dimensional images of several immature "shale" samples were constructed at resolutions close to 5 um. This is sufficient to resolve the source-rock structure down to the grain level, but very-fine-grained silt particles, clay particles, and colloids cannot be resolved. Samples used in this investigation came from the R-8 unit in the upper part of the Green River shale, which is organic rich, varved, lacustrine marl formed in Eocene Lake Uinta, USA. One Green River shale sample was heated in situ up to 400 degrees C as X-ray-tomography images were recorded. The other samples were scanned before and after heating at 400 degrees C. During the heating phase, the organic matter was decomposed, and gas was released. Gas expulsion from the low-permeability shales was coupled

  18. Geogenic Factors as Drivers of Microbial Community Diversity in Soils Overlying Polymetallic Deposits

    PubMed Central

    Zammit, Carla M.; Pohrib, Rebecca; Gregg, Adrienne L.; Wakelin, Steven A.

    2015-01-01

    This study shows that the geogenic factors landform, lithology, and underlying mineral deposits (expressed by elevated metal concentrations in overlying soils) are key drivers of microbial community diversity in naturally metal-rich Australian soils with different land uses, i.e., agriculture versus natural bushland. One hundred sixty-eight soil samples were obtained from two metal-rich provinces in Australia, i.e., the Fifield Au-Pt field (New South Wales) and the Hillside Cu-Au-U rare-earth-element (REE) deposit (South Australia). Soils were analyzed using three-domain multiplex terminal-restriction-fragment-length-polymorphism (M-TRFLP) and PhyloChip microarrays. Geogenic factors were determined using field-mapping techniques and analyses of >50 geochemical parameters. At Fifield, microbial communities differed significantly with geogenic factors and equally with land use (P < 0.05). At Hillside, communities in surface soils (0.03- to 0.2-m depth) differed significantly with landform and land use (P < 0.05). Communities in deeper soils (>0.2 m) differed significantly with lithology and mineral deposit (P < 0.05). Across both sites, elevated metal contents in soils overlying mineral deposits were selective for a range of bacterial taxa, most importantly Acidobacteria, Bacilli, Betaproteobacteria, and Epsilonproteobacteria. In conclusion, long-term geogenic factors can be just as important as land use in determining soil microbial community diversity. PMID:26341204

  19. A mineralogical application of micro-PIXE technique: The Ni-Mo-PGE polymetallic layer of black shales in Zunyi region, South China

    NASA Astrophysics Data System (ADS)

    Li, X.; Han, T.; Zhu, X.; Li, Y.; Zheng, Y.; Shen, H.

    2013-08-01

    The Ni-Mo-PGE polymetallic layers, from Southern China (Huangjiawan mine, Zunyi region, northern part of the Guizhou Province), were analyzed by micro-PIXE. These samples are known to be enriched with acidic elements and basic elements. Some of them, like Ag, Au, Pt, Pd, Se and Mo, are of large economic value. The distributions of Fe, Mo, Ni, As, Se and Pd in black shales samples are studied. The correlation among those elements has also been investigated. Trace element data from minerals, the noble metals' mode of occurrence and correlation with other elements are all significant in mineralogy. Such information can help in understanding the genesis of the deposit and also aid the exploration strategy.

  20. DEFINITION OF MULTIVARIATE GEOCHEMICAL ASSOCIATIONS WITH POLYMETALLIC MINERAL OCCURRENCES USING A SPATIALLY DEPENDENT CLUSTERING TECHNIQUE AND RASTERIZED STREAM SEDIMENT DATA - AN ALASKAN EXAMPLE.

    USGS Publications Warehouse

    Jenson, Susan K.; Trautwein, C.M.

    1984-01-01

    The application of an unsupervised, spatially dependent clustering technique (AMOEBA) to interpolated raster arrays of stream sediment data has been found to provide useful multivariate geochemical associations for modeling regional polymetallic resource potential. The technique is based on three assumptions regarding the compositional and spatial relationships of stream sediment data and their regional significance. These assumptions are: (1) compositionally separable classes exist and can be statistically distinguished; (2) the classification of multivariate data should minimize the pair probability of misclustering to establish useful compositional associations; and (3) a compositionally defined class represented by three or more contiguous cells within an array is a more important descriptor of a terrane than a class represented by spatial outliers.

  1. Late-Hercynian intrusion-related gold deposits: An integrated model on the Tighza polymetallic district, central Morocco

    NASA Astrophysics Data System (ADS)

    Éric, Marcoux; Khadija, Nerci; Yannick, Branquet; Claire, Ramboz; Gilles, Ruffet; Jean-Jacques, Peucat; Ross, Stevenson; Michel, Jébrak

    2015-07-01

    radiogenic isotope studies. Nd and Sr isotope compositions of scheelite and granites suggest the participation of a juvenile component while lead isotopes demonstrate a major participation of the basement. Both gold mineralization and zoning suggest that the system developed at the end of the magmatic activity, accompanying a major transition in magmatic fluid composition. The morphology of the gold-bearing mineralization is dependent of the permeability and the reactivity of host-rocks: focus circulation of fluids through pre-existing tectonic corridors, reactivated by late-Hercynian intrusions favor the formation of large W-type gold veins, while infiltration of fluid within reactive stratigraphic layers gives rise to skarn mineralization. A 40Ar/39Ar date (W1 north vein: 291.8 ± 0.3 Ma) indicates that hydrothermal circulation predates gold and tungsten deposition in open fractures as well as Mine granite emplacement. The W-Au mineralization preceded the onset of a large convective hydrothermal cell around the intrusion that led to the formation of the Pb-Ag-Zn mined veins. The Tighza polymetallic district displays numerous similarities with the R-IRG model that was defined in the American Cordillera, such as thermal and zonation patterns, carbonic hydrothermal fluids and chronology of intrusion and related deposits, but also provides new insight to the R-IRG model such as wide Au-quartz veins instead of sheeted Au-veins, oxidation state of the magma, and Sr-Nd isotopic data. These results establish a major magmatic contribution and discard a direct genetic relationship between gold mineralization and major neighboring Pb-Ag-Zn veins. A large number of classic Pb-Zn district of the Western Hercynides belong to the same clan.

  2. Reforming with polymetallic catalysts

    SciTech Connect

    Baird, W.C. Jr.

    1988-11-29

    This patent describes a process for catalytically reforming, with hydrogen, a hydrocarbon naphtha feed at reforming conditions, the improvement comprising contacting the naphtha feed, and hydrogen, with a halogenated, supported platinum-rhenium catalyst promoted with iridium agglomerated to exhibit a crystallinity greater than 50 percent, as measured by X-ray.

  3. Mobilization of soluble and dispersible lead, arsenic, and antimony in a polluted, organic-rich soil - effects of pH increase and counterion valency.

    PubMed

    Klitzke, Sondra; Lang, Friederike

    2009-01-01

    Liming is a common technique suggested for the stabilization of shooting range sites. We investigated the effect of an increase in pH on the mobilization of soluble and dispersible (colloidal) Pb, As, and Sb. Our hypothesis was that the addition of divalent cations counteracts the pH-induced mobilization of soluble and colloidal metal(loid)s. We determined soluble (operationally defined as the fraction < 10 nm obtained after centrifugation) and dispersible (filter cut-off 1200 nm) As, Pb, Sb, Fe, and C(org) concentrations in the filtered suspensions of batch extracts of topsoil samples (C(org): 8%) from a former shooting range site following a pH increase to values between 3.5 and 7 by adding a monovalent (KOH) or a divalent (Ca(OH)(2)) base. In the Ca(OH)(2)-treated samples, dissolved metal(loid) concentrations were 62 to 98% lower than those titrated with KOH to similar pH. Similarly, Ca reduced the concentration of dispersible Pb by 95%, but had little or no impact on dispersible As and Sb. We conclude that the counterion valency controls the mobility of metal(loid)s by affecting the mobility and sorption capacity of the sorbents (e.g., colloids, organic matter).

  4. Tin-polymetallic sulfide deposits in the eastern part of the Dachang tin field (South China) and the role of black shales in their origin

    NASA Astrophysics Data System (ADS)

    Pašava, Jan; Kříbek, Bohdan; Dobeš, Petr; Vavřín, Ivan; Žák, Karel; Delian, Fan; Tao, Zhang; Boiron, Marie-Christine

    2003-01-01

    The Dafulou and Huile vein and stratabound cassiterite-sulfide deposits and sheeted ore veins at the Kangma cassiterite-sulfide deposit are located in the eastern part of the Dachang tin field. These deposits are hosted in a sedimentary sequence containing significant concentrations of organic matter in the form of Lower Devonian calcareous black shales and hornfels. These rocks together with the younger intrusion of Longxianggai granite (91±2 Ma) actively participated in the formation of Sn-polymetallic deposits. The following three major stages have been distinguished in stratiform and vein-type orebodies at Dafulou, Huile and Kangma: stage I (cassiterite, pyrrhotite, arsenopyrite, tourmaline, carbonate), stage II - main sulfide stage (quartz, cassiterite, arsenopyrite, pyrrhotite, sphalerite, stannite, pyrite, carbonates) and stage III (native Bi, galena, electrum, sulfosalts). Stage IV (post-ore), recognized at Huile is represented by barren carbonates and zeolites. Whole rock geochemistry has revealed that at Dafulou, Bi and Cu correlate strongly with S, whereas V and Pb correlate well with Corg (organic carbon). The similar distribution patterns of selected elements in average slightly mineralized low-Ca black shales indicate a fluid composition similar for all deposits studied. Studies of graphitization of the organic matter in black shales adjacent to orebodies indicate that d(002) and FWHM (full width in half maximum)/peak height values gradually decrease in the following sequence: Dafulou deposit → Kangma deposit → Huile deposit. The pyrolysate of wall rocks at the Dafulou deposit is relatively enriched in asphaltenes and maltenes (55.6-72.0% of the pyrolysate) comparable with pyrolysate obtained from more distal black shales (19.2-28.5%). Typical GC-MS spectra of pyrolysate from distal black shales are dominated by alkanes in the n-C15 to n-C25 range, aromatic molecules being represented mostly by alkyl-naphthalenes. In contrast, only traces of

  5. Biogeochemical cycling in an organic-rich coastal marine basin. 8. A sulfur isotopic budget balanced by differential diffusion across the sediment-water interface

    USGS Publications Warehouse

    Chanton, J.P.; Martens, C.S.; Goldhaber, M.B.

    1987-01-01

    The sulfur isotopic composition of the sulfur fluxes occurring in the anoxic marine sediments of Cape Lookout Bight, N.C., U.S.A., was determined, and the result of isotopic mass balance was obtained via the differential diffusion model. Seasonal pore water sulfate ??34S measurements yielded a calculated sulfate input of 0.6%.. Sulfate transported into the sediments via diffusion appeared to be enriched in the lighter isotope because its concentration gradient was steeper, due to the increase in the measured isotopic composition of sulfate with depth. Similarly, the back diffusion of dissolved sulfide towards the sediment-water interface appeared enriched in the heavier isotope. The isotopic composition of this flux was calculated from measurements of the ??34S of dissolved sulfide and was determined to be 15.9%.. The isotopic composition of buried sulfide was determined to be -5.2%. and the detrital sulfur input was estimated to be -6.2%.. An isotope mass balance equation based upon the fluxes at the sediment-water interface successfully predicted the isotopic composition of the buried sulfur flux within 0.5%., thus confirming that isotopes diffuse in response to their individual concentration gradients. ?? 1987.

  6. U-Pb, Re-Os and Ar-Ar dating of the Linghou polymetallic deposit, Southeastern China: Implications for metallogenesis of the Qingzhou-Hangzhou metallogenic belt

    NASA Astrophysics Data System (ADS)

    Tang, Yanwen; Xie, Yuling; Liu, Liang; Lan, Tingguan; Yang, Jianling; Sebastien, Meffre; Yin, Rongchao; Liang, Songsong; Zhou, Limin

    2017-04-01

    The Qingzhou-Hangzhou metallogenic belt (QHMB) in Southeastern China has gained increasingly attention in recent years. However, due to the lack of reliable ages on intrusions and associated deposits in this belt, the tectonic setting and metallogenesis of the QHMB have not been well understood. The Linghou polymetallic deposit in northwestern Zhejiang Province is one of the typical deposits of the QHMB. According to the field relationships, this deposit consists of the early Cu-Au-Ag and the late Pb-Zn-Cu mineralization stages. Molybdenite samples with a mineral assemblage of molybdenite-chalcopyrite-pyrite ± quartz are collected from the copper mining tunnel near the Cu-Au-Ag ore bodies. Six molybdenite samples give the Re-Os model ages varying from 160.3 to 164.1 Ma and yield a mean age of 162.2 ± 1.4 Ma for the Cu-Au-Ag mineralization. Hydrothermal muscovite gives a well-defined Ar-Ar isochron age of 160.2 ± 1.1 Ma for the Pb-Zn-Cu mineralization. Three phases of granodioritic porphyry have been distinguished in this deposit, and LA-ICP-MS zircon U-Pb dating shows that they have formed at 158.8 ± 2.4 Ma, 158.3 ± 1.9 Ma and 160.6 ± 2.1 Ma, comparable to the obtained ages of the Cu-Au-Ag and Pb-Zn-Cu mineralization. Therefore, these intrusive rocks have a close temporal and spatial relationship with the Cu-Au-Ag and Pb-Zn-Cu ore bodies. The presences of skarn minerals (e.g., garnet) and vein-type ores, together with the previous fluid inclusion and H-O-C-S-Pb isotopic data, clearly indicate that the Cu-Au-Ag and Pb-Zn-Cu mineralization are genetically related to these granodiorite porphyries. This conclusion excludes the possibility that this deposit is of ;SEDEX; type and formed in a sag basin of continental rifts setting as previously proposed. Instead, it is proposed that the Linghou polymetallic and other similar deposits in the QHMB, such as the 150-160 Ma Yongping porphyry-skarn Cu-Mo, Dongxiang porphyry? Cu, Shuikoushan/Kangjiawang skarn Pb

  7. Trace metal cycling and 238U/235U in New Zealand's fjords: Implications for reconstructing global paleoredox conditions in organic-rich sediments

    NASA Astrophysics Data System (ADS)

    Hinojosa, Jessica L.; Stirling, Claudine H.; Reid, Malcolm R.; Moy, Christopher M.; Wilson, Gary S.

    2016-04-01

    Reconstructing the history of ocean oxygenation provides insight into links between ocean anoxia, biogeochemical cycles, and climate. Certain redox-sensitive elements respond to changes in marine oxygen content through phase shifts and concomitant isotopic fractionation, providing new diagnostic proxies of past ocean hypoxia. Here we explore the behavior and inter-dependence of a suite of commonly utilized redox-sensitive trace metals (U, Mo, Fe, and Mn) and the emerging "stable" isotope system of U (238U/235U, or δ238U) in New Zealand fjords. These semi-restricted basins have chemical conditions spanning the complete redox spectrum from fully oxygenated to suboxic to intermittently anoxic/euxinic. In the anoxic water column, U and Mo concentrations decrease, while Fe and Mn concentrations increase. Similarly, signals of past euxinic conditions can be found by U, Mo, Fe, and Mn enrichment in the underlying sediments. The expected U isotopic shift toward a lower δ238U in the anoxic water column due to U(VI)-U(IV) reduction is not observed; instead, water column δ238U profiles are consistent in fjords of all oxygen content, falling within previously reported ranges for open ocean seawater (δ238U = -0.42 ± 0.07‰). Additionally, surface sediment δ238U results show evidence for competing U isotope fractionation processes. One site indicates increased export of 238U from seawater to the underlying sediments (fractionation between aqueous seawater U and particulate sediment U, or ΔU(aq)-U(solid) = -0.25‰), consistent with redox-driven fractionation. Another site suggests potential U(VI) adsorption-driven fractionation, reflecting increased export of 235U from seawater to sediments (ΔU(aq)-U(solid) = 0.25‰). We discuss several potential factors that could alter δ238U in waters and sediments beyond redox-driven shifts, including adsorption to organic matter in waters of high primary productivity, reaction rates for competing processes of U adsorption and

  8. High-resolution Carbon and Trace Element Geochemistry in Early-Middle Aptian Organic-Rich Sediments of the El Pui section, Cataluña, Spain

    NASA Astrophysics Data System (ADS)

    Sanchez-Hernandez, Y.; Maurrasse, F. J.

    2013-12-01

    Darker and more expanded layers characterize the interval of the El Pui section, Organyà Basin that correlates with the early-middle Aptian. They contrast with the earlier levels from the latest Barremian to the earliest Aptian interval, suggesting intensified OM sequestration in the superjacent layers. Accentuated conditions conducive to increased OM accumulation are revealed in the high-resolution δ13Corg curve that corroborates intensified primary productivity as seen elsewhere. Increasing trends in elemental concentrations of Al, Si and Ti normalized with respect to TIC, further support the changing conditions and sustained transport of terrestrial material to the basin. Similarly, clay minerals results indicate intensified breakdown of continental rocks and rapid burial of clay. Enrichment of redox-sensitive trace elements (Ni, V, Co, Cr, U, and Th) at certain levels attests that concurrent reducing conditions prevailed, culminating with temporal development of an anoxic phase. Microfacies characterized by rare to absent benthic fauna are in agreement with the geochemical results suggesting stressful bottom water conditions marked by oxygen deficiency. The integrated results thus indicate that existent intermittent oxygen-depleted conditions in sediments of the El Pui section became accentuated during the early Aptian leading to enhanced OM sequestration. Intensified global paleoceanographic and paleoclimatic changes in the early Aptian, superimposed on specific physiographic characteristics of the semi-enclosed basin and its adjacent landmasses, may have resulted in intensified nutrient delivery to the basin, increased productivity, and water column stratification that caused severe oxygen depletion.

  9. Petrographic Evidence of Microbial Mats in the Upper Cretaceous Fish-Bearing, Organic-Rich Limestone, Agua Nueva Formation, Central Mexico

    NASA Astrophysics Data System (ADS)

    Blanco, A.; Maurrasse, F. J.; Hernández-Ávila, J.; Ángeles-Trigueros, S. A.; García-Cabrera, M. E.

    2013-05-01

    assemblages. Absence of bioturbation, pervasive framboidal pyrite, and the high concentration of organic matter (TOC ranges from 1.2% to 8wt%) in the dark limestones are consistent with persistent recurring dysoxic/anoxic conditions, and the light-gray bioturbated limestones represent relatively well-oxygenated episodes. Planktonic foraminifera (Rotalipora cushmani) and Inoceramu labiatus indicate a time interval from the latest Cenomanian through the earliest Turonian, thus this long interval of severe oxygen deficiency is coeval with Oceanic Anoxic Event 2 (OAE-2). [Duque-Botero and Maurrasse. 2005. Jour. Iberian Geology (31), 85-98; 2008. Cret. Res., 29, 957-964; Kremer. 2006. Acta Palaeontologica Polonica (51, 1), 143-154

  10. Complex conductivity of organic-rich shales

    NASA Astrophysics Data System (ADS)

    Woodruff, W. F.; Revil, A.; Torres-Verdin, C.

    2013-12-01

    We can accurately determine the intrinsic anisotropy and material properties in the laboratory, providing empirical evidence of transverse isotropy and the polarization of the organic and metallic fractions in saturated and unsaturated shales. We develop two distinct approaches to obtain the complex conductivity tensor from spectral induced polarization (SIP) measurements. Experimental results indicate clear anisotropy, and characterize the effects of thermal maturation, TOC, and pyrite, aiding in the calibration and interpretation of geophysical data. SIP is a non-intrusive measurement, sensitive to the surface conductance of mineral grains, frequency-dependent polarization of the electrical double layer, and bulk conductivity of the pore water. The in-phase and quadrature components depend upon parameters of principal importance in unconventional shale formation evaluation (e.g., the distribution of pore throat sizes, formation factor, permeability, salinity and cation exchange capacity (CEC), fluid saturation and wettability). In addition to the contribution of the electrical double layer of non-conducting minerals to surface conductivity, we have observed a clear relaxation associated with kerogen pyrolysis, pyrite distribution, and evidence that the CEC of the kerogen fraction may also contribute, depending on thermal maturation history. We utilize a recent model for anisotropic complex conductivity, and rigorous experimental protocols to quantify the role of kerogen and pyrolysis on surface and quadrature conductivity in mudrocks. The complex conductivity tensor σ* describes the directional dependence of electrical conduction in a porous medium, and accounts for both conduction and polarization. The complex-valued tensor components are given as σ*ij , where σ'ij represents in-phase and σ"ij denotes quadrature conductivities. The directional dependence of the complex conductivity tensor is relegated to the textural properties of the material. The components of the formation factor and connectivity (tortuosity) tensors Fij and Tij (affecting the bulk and surface conductivity, respectively) are correlated as Fij=TijΦ. Both conductivity and connectivity tensors share the same eigenvectors; the anisotropy ratio is equivalent in TI media. At high pore water salinity, surface and quadrature conductivity share the same bulk tortuosity; when surface conductivity dominates (low salinity), conductivity is controlled by the surface conductance, and the tortuosity of electrical current along mineral surfaces usually higher than that of the pore water. We developed two distinct SIP measurement protocols to obtain the tensor: (1) azimuthal sampling and inversion of phasor potentials through the full-field solution of the Laplace equation; (2) direct measurement of complex conductivity eigenvalues by polarized, single-component stimulus current. Experiments also include unsaturated and saturated measurements with three brines of known salinity and pH, at log-distributed frequencies ranging 1 mHz to 45 kHz. Both azimuthal spectra and eigenvalue spectra validate the theoretical model and illustrate the effectiveness of the protocols themselves. We obtain the textural tensors and invert key parameters including Archie exponents and CEC, and characterize the relaxation phenomena associated with kerogen content and maturity for multiphase fluid systems.

  11. U-Pb geochronology, geochemistry, and H-O-S-Pb isotopic compositions of the Leqingla and Xin'gaguo skarn Pb-Zn polymetallic deposits, Tibet, China

    NASA Astrophysics Data System (ADS)

    Wang, Liqiang; Cheng, Wenbin; Tang, Juxing; Kang, Haoran; Zhang, Yan; Li, Zhuang

    2016-01-01

    The Leqingla and Xin'gaguo deposits are two representative skarn Pb-Zn polymetallic deposits of the Gangdese Pb-Zn polymetallic belt, Tibet, China. LA-ICP-MS zircon U-Pb dating of the mineralization-related biotite granites from both the Leqingla and Xin'gaguo deposits yielded weighted mean ages of 60.8 Ma and 56.5 Ma, respectively, which can be inferred as their mineralization ages. The Leqingla biotite granite is characterized by high Al2O3, total Fe, Na2O, and low K2O. In comparison, the Xin'gaguo biotite granite is characterized by relative higher K2O but lower Al2O3, total Fe, and Na2O. Geochemical and mineralogical characteristics indicate that the Leqingla and Xin'gaguo biotite granites are calc-alkaline I-type granite and High K calc-alkaline I-type granite, respectively. Both the Leqingla and Xin'gaguo biotite granites are enrichment in LREE and LILEs and depletion in HFSEs, and they were formed at the India-Asia collision stage. δ18O and δD values for the Leqingla and Xin'gaguo deposits are -8.8‰ to 5.3‰ and -140.4‰ to -90.1‰, -4.5‰ to 7.0‰ and -117.3‰ to -81.0‰, respectively, indicating magma fluids mixed with meteoric water in ore-forming fluids. δ34S values (-11.6‰ to -0.3‰) of ore sulfides from the Leqingla deposit show characteristics of biogenetic sulfur isotope compositions, suggesting sulfur for the Leqingla deposit were sourced from wall rocks of the Mengla and Luobadui Formation, which are rich in organic materials. δ34S values of ore sulfides from the Xin'gaguo deposits show bimodal distribution (-5.0‰ to -1.6‰ and 1.6-2.1‰), indicating sulfur in the Xin'gaguo deposit were derived from both wall rocks and magma. In the Leqingla deposit, most ore sulfides have the similar Pb isotopic compositions with that of the mineralization-related biotite granite, suggesting the biotite granite supplied most of the ore-forming metals. Pb isotopic compositions of ore sulfides and Hf isotopic compositions of biotite granite show

  12. Geochemical characterisation of Tithonian-Berriasian Chia Gara organic-rich rocks in northern Iraq with an emphasis on organic matter enrichment and the relationship to the bioproductivity and anoxia conditions

    NASA Astrophysics Data System (ADS)

    Mohialdeen, Ibrahim M. J.; Hakimi, Mohammed Hail

    2016-02-01

    Tithonian-Berriasian Chia Gara organic-rich rocks, located in Kurdistan (northern Iraq), were analysed based on inorganic and organic geochemistry to define the origin, type of organic matter, and the influencing factors of organic matter (OM) enrichment, including the OM input and preservation, and their relationship to the paleoenvironment conditions. The δ13Corg values of the Chia Gara rocks range from -29.99‰ to -26.93‰, with average values of approximately -28.8‰, indicating that the organic matter has a predominantly marine origin. Enhanced biological productivity within the photic zone of the water column during deposition of the Chia Gara Fm. is indicated by consistently high organic carbon content in most samples (average 3 wt.%), as well as by bulk geochemical and biomarker characteristics. Major contributions by aquatic algae and microorganisms with a minor terrigenous organic matter contribution are indicated by the n-alkane distribution patterns and the composition of the hopanoids, steroids, and tricyclic terpenoids. Strongly reducing bottom water is indicated by low pristane/phytane ratios, homohopane distribution patterns, and the redox-sensitive trace elements geochemistry. Salinity stratification with alkaline bottom waters is indicated by high Sr/Ba ratios and the presence of gammacerane in the analysed Chia Gara samples. These data indicate that OM enrichment in the Tithonian-Berriasian Chia Gara rocks results from the combination of enhanced biological productivity and salinity stratification with anoxic bottom water conditions, which favoured OM preservation.

  13. [Spectral characteristics and implications of quartz from Heliao lead-zinc polymetallic ore district in the south of Qinzhou-Hangzhou joint belt].

    PubMed

    Lü, Wen-Chao; Yang, Zhi-Jun; Zhou, Yong-Zhang; Li, Hong-Zhong; Zeng, Xiang-Qing; Chen, Qing; Liang, Jin; Zeng, Chang-Yu

    2013-05-01

    The XRD, FTIR and Raman spectrum were employed to study the characters of quartz from three types of rock samples, which are mineralized rock sample, near ore body rock sample and far away from ore body rock sample in Heliao lead-zinc polymetallic ore district. The research shows that the quartz in the mineralized rock and far away from ore body rock is pure, while the quartz in near ore body rock contains a small amount of impurities. But such small amounts of impurities did not cause apparent change in the quartz lattice parameters. From far away from ore body rock-->near ore body rock-->mineralized rock, the crystallinity and order degree of quartz are higher and higher. And the quartz in the mineralized rock has a trend to change into low symmetry quartz. It's a unique to mineralized rock that the quartz's absorption peak at 1 050 cm(-1) was split into two strongest ones. It can be used as the signs of whether exists mineralization. The cause for the quartz microstructure changes may be related to the activities of late mineralized hydrothermal fluids. Late hydrothermal influence was very weak to the quartz far away from ore body rock. And through the impact of the multi-stage hydrothermal effect, the quartz in mineralized rock may be purified by recrystallization and structural adjustment. However the quartz in near ore body rock didn't have enough hydrothermal influence, so it's not pure. Genealogy research technology is a useful technique for in-depth exploration of study area mineralization process and metallogenic regularity.

  14. Genesis of the Bangbule Pb-Zn-Cu polymetallic deposit in Tibet, western China: Evidence from zircon U-Pb geochronology and S-Pb isotopes

    NASA Astrophysics Data System (ADS)

    Kan, Tian; Zheng, Youye; Gao, Shunbao

    2016-04-01

    The Banbule Pb-Zn-Cu skarn deposit is located in the Longger-Gongbujiangda volcanic magma arc in the Gangdese-Nyainqentanglha Plate. It is the only lead-zinc polymetallic deposit discovered in the westernmost Nyainqentanglha metallogenic belt. The measured and indicated resources include 0.9 Mt of Pb+Zn (4.77% Pb and 4.74% Zn, respectively), 6499 t of Cu, and 178 t of Ag (18.75g/t Ag). The orebodies mainly occur as lenses, veins and irregular shapes in the contact zone between the quartz-porphyry and limestone of the Upper Permian Xiala Formation, or in the boundaries between limestone and sandstone. Pb-Zn-Cu mineralization in the Banbule deposit is closely associated with skarns. The ore minerals are dominated by galena, sphalerite, chalcopyrite, bornite, and magnetite, with subordinate pyrite, malachite, and azurite. The gangue minerals are mainly garnet, actinolite, diopside, quartz, and calcite. The ore-related quartz-porphyry displays LA-ICP-MS zircon U-Pb age of 77.31±0.74 Ma. The δ34S values of sulfides define a narrow range of -0.8 to 4.7‰ indicating a magmatic source for the ore-forming materials. Lead isotopic systematics yield 206Pb/204Pb of 18.698 to 18.752, 207Pb/204Pb of 15.696 to 15.760, and 208Pb/204Pb of 39.097 to 39.320. The data points are constrained around the growth curves of upper crust and orogenic belt according to the tectonic discrimination diagrams. The calculated Δβ - Δγ values plot within the magmatic field according to the discrimination diagram of Zhu et al. (1995). The S-Pb isotopic data suggest that Bangbule is a typical skarn deposit, and the Pb-Zn-Cu mineralization is genetically related to the quartz-porphyry in the mining district. The discovery of the Bangbule deposit indicates that there is metallogenic potential in the westernmost Nyainqentanglha belt, which is of great importance for the exploration work in this area.

  15. Weathering and its effect upon geochemical dispersion at the polymetallic Wagga Tank deposit, N.S.W., Australia

    USGS Publications Warehouse

    Scott, K.M.; Rabone, G.; Chaffee, M.A.

    1991-01-01

    The Wagga Tank Zn-Pb-Cu-Ag-Au deposit comprises multiple, steeply dipping and structurally controlled sulfide lodes within Early Devonian turbidites and volcaniclastics. Complete weathering at the prospect extends to 100 m below the current land surface. Detailed geochemical studies of drill-derived regolith material were supplemented by extensive mineralogical investigations and enable the major features of the weathered profile to be delineated. The profile consists of soil with reworked portions of a ferruginous lateritic capping within a largely transported overburden. Below the soil, some residual ferruginous capping (characterized by maghemite) occurs above a kaolinite-rich zone which passes into goethitic saprolite containing alunitejarosite family minerals. This lateritic profile was developed during the Tertiary period prior to the Late Miocene onset of more arid conditions. Within the goethitic saprolite, Pb and some Au have remained in their Miocene positions. However, the distributions of Cu and Zn largely reflect the effect of post-Miocene aridity. Thus, these elements (and some Au) are concentrated as supergene minerals at the current water table, with isolated zones higher in the weathered profile reflecting former levels of the water table. Preferential sampling of ferruginous lateritic material in the overlying transported soil can enhance geochemical anomalies and indicate the presence of concealed mineralization at Wagga Tank. ?? 1991.

  16. Comprehensive biological effects of a complex field poly-metallic pollution gradient on the New Zealand mudsnail Potamopyrgus antipodarum (Gray).

    PubMed

    Gust, M; Buronfosse, T; Geffard, O; Coquery, M; Mons, R; Abbaci, K; Giamberini, L; Garric, J

    2011-01-17

    The Lot River is known to be contaminated by metals, mainly cadmium and zinc, due to a former Zn ore treatment plant in the watershed of the Riou-Mort, a tributary of the Lot River. Many studies have been performed to characterize contamination, but few have assessed its consequences on the biological responses of organisms along the gradient. We exposed adult and juvenile New Zealand freshwater mudsnails Potamopyrgus antipodarum at several sites along the gradient of metal contamination for 28 days. Biological responses were monitored at different levels: individual (survival, growth and fecundity), tissue and biochemical (energy status and vertebrate-like sex steroid levels) to better understand the toxicity mechanisms involved. Accumulation of Cd and Zn was high during exposure. Most of the biological effects observed could be linked to this contamination and were concentration-dependent. Histological lesions of the digestive gland were observed, with hypertrophy of calcium cells and vacuolization of digestive cells. Such effects are likely to explain the decrease of energy status (triglycerides and proteins), juvenile growth and adult fecundity observed at the most polluted site. However the magnitude of the fall in fecundity cannot be attributed only to these tissular effects, indicating another mode of action of Cd or possible confounding factors. Steroid accumulation in snails indicated only organic pollution. Histopathological effects proved the most sensitive endpoint to metal (Cd and Zn) contamination. Copyright © 2010 Elsevier B.V. All rights reserved.

  17. Biomarker responses of Eisenia andrei to a polymetallic gradient near a lead mining site in North Tunisia.

    PubMed

    Boughattas, Iteb; Hattab, Sabrine; Boussetta, Hamadi; Sappin-Didier, Valérie; Viarengo, Aldo; Banni, Mohamed; Sforzini, Susanna

    2016-11-01

    Eisenia andrei earthworms were exposed for 7 and 14 days to six samples of soil taken from around an abandoned lead (Pb) mine and characterized by different levels of metal contamination (S6-S1, this latter being the most contaminated soil). The organisms were analyzed for metal bioaccumulation and for biological parameters as biomarkers of stress (lysosomal membrane stability; lipofuscin lysosomal content; lysosomal/cytoplasmic volume ratio) and genotoxicity (Micronucleus frequency). Chemical analysis showed the loads of Pb, Cd, Zn, and Cu in the worms following exposure. Among the stress biomarkers, lysosomal membrane stability was significantly affected in the coelomocytes of the earthworms exposed already 7 days to different contaminated soils. Organisms exposed for 14 days to S1 showed in the cells of the chloragogenous tissue, a particularly relevant increase in lipofuscin, a biomarker of oxidative stress, and an increase in the lysosome/cytoplasm volume ratio, indicating stressful condition at the tissue level. Moreover, in the same conditions, a decrease in total body weight was observed. At the longer exposure time, the coelomocytes of worms exposed to S1, S2, and S3 (soils with higher metal concentrations) showed a significant increase in micronuclei (MNi) frequency. Expressions of the P21 and topoisomerase genes, which are involved in DNA repair, showed significant up-regulation in the cells of worms exposed to S1, S2, S3, S4 and to a less extend S6. This may indicate that the worms were only able to successfully reduce the level of DNA damage in S4 and S5 if considering MN frequency data. The biomarker data was integrated by the Earthworm Expert System, allowing an objective interpretation of the complex biological data and clearly defining the areas in which the presence of chemicals is toxic for the edaphic organisms. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Sedimentary carbonate-hosted giant Bayan Obo REE-Fe-Nb ore deposit of Inner Mongolia, China; a cornerstone example for giant polymetallic ore deposits of hydrothermal origin

    USGS Publications Warehouse

    Chao, E.C.T.; Back, J.M.; Minkin, J.A.; Tatsumoto, M.; Junwen, Wang; Conrad, J.E.; McKee, E.H.; Zonglin, Hou; Qingrun, Meng; Shengguang, Huang

    1997-01-01

    Detailed, integrative field and laboratory studies of the textures, structures, chemical characteristics, and isotopically determined ages and signatures of mineralization of the Bayan Obo deposit provided evidence for the origin and characteristics favorable for its formation and parameters necessary for defining giant polymetallic deposits of hydrothermal origin. Bayan Obo is an epigenetic, metasomatic, hydrothermal rare earth element (REE)-Fe-Nb ore deposit that is hosted in the metasedimentary H8 dolostone marble of the Middle Proterozoic Bayan Obo Group. The metasedimentary sequence was deposited on the northern continental slope of the North China craton. The mine area is about 100 km south of the suture marking Caledonian subduction of the Mongolian oceanic plate from the north beneath the North China craton. The mineralogy of the deposit is very complex, consisting of more than 120 different minerals, some of which are epigenetic minerals introduced by hydrothermal solutions, and some of which are primary and secondary metamorphic minerals. The major REE minerals are monazite and bastnaesite, whereas magnetite and hematite are the dominant Fe-ore minerals, and columbite is the most abundant Nb mineral. Dolomite, alkali amphibole, fluorite, barite, aegirine augite, apatite, phlogopite, albite, and microcline are the most widespread gangue minerals. Three general types of ores occur at Bayan Obo: disseminated, banded, and massive ores. Broad zoning of these ore types occurs in the Main and East Orebodies. Disseminated ores are in the outermost zone, banded ores are in the intermediate zone, and massive ores are in the cores of the orebodies. On the basis of field relations, host rocks, textures, structures, and mineral assemblages, many varieties of these three types of ores have been recognized and mapped. Isotopic dating of monazite, bastnaesite, aeschynite, and metamorphic and metasomatic alkali amphiboles associated with the deposit provides constraints

  19. Variations in the chemical and stable isotope composition of carbon and sulfur species during organic-rich sediment alteration: An experimental and theoretical study of hydrothermal activity at guaymas basin, gulf of california

    USGS Publications Warehouse

    Seewald, Jeffrey S.; Seyfried, W.E.; Shanks, Wayne C.

    1994-01-01

    Organic-rich diatomaceous ooze was reacted with seawater and a Na-Ca-K-Cl fluid of seawater chlorinity at 325-400??C, 400-500 bars, and fluid/sediment mass ratios of 1.56-2.35 to constrain factors regulating the abundance and stable isotope composition of C and S species during hydrothermal alteration of sediment from Guaymas Basin, Gulf of California. Alteration of inorganic and organic sedimentary components resulted in extensive exchange reactions, the release of abundant H2S, CO2, CH4, and Corganic, to solution, and recrystallization of the sediment to an assemblage containing albitic plagioclase, quartz, pyrrhotite, and calcite. The ??34Scdt values of dissolved H2S varied from -10.9 to +4.3??? during seawater-sediment interaction at 325 and 400??C and from -16.5 to -9.0??? during Na-Ca-K-Cl fluid-sediment interaction at 325 and 375??C. In the absence of seawater SO4, H2S is derived from both the transformation of pyrite to pyrrhotite and S released during the degradation of organic matter. In the presence of seawater SO4, reduction of SO4 contributes directly to H2S production. Sedimentary organic matter acts as the reducing agent during pyrite and SO4 reduction. Requisite acidity for the reduction of SO4 is provided by Mg fixation during early-stage sediment alteration and by albite and calcite formation in Mg-free solutions. Organically derived CH4 was characterized by ??13Cpdb values ranging between -20.8 and -23.1???, whereas ??13Cpdb values for dissolved Corganic ranged between -14.8 and -17.7%. Mass balance calculations indicate that ??13C values for organically derived CO2 were ??? - 14.8%. Residual solid sedimentary organic C showed small (??? 0.7???) depletions in 13C relative to the starting sediment. The experimental results are consistent with the isotopic and chemical composition of natural hydrothermal fluids and minerals at Guaymas Basin and permit us to better constrain sources and sinks for C and S species in subseafloor hydrothermal systems

  20. Variations in the chemical and stable isotope composition of carbon and sulfur species during organic-rich sediment alteration: An experimental and theoretical study of hydrothermal activity at guaymas basin, gulf of california

    NASA Astrophysics Data System (ADS)

    Seewald, Jeffrey S.; Seyfried, William E., Jr.; Shanks, Wayne C., III

    1994-11-01

    Organic-rich diatomaceous ooze was reacted with seawater and a Na-Ca-K-Cl fluid of seawater chlorinity at 325-400°C, 400-500 bars, and fluid/sediment mass ratios of 1.56-2.35 to constrain factors regulating the abundance and stable isotope composition of C and S species during hydrothermal alteration of sediment from Guaymas Basin, Gulf of California. Alteration of inorganic and organic sedimentary components resulted in extensive exchange reactions, the release of abundant H 2S, CO 2, CH 4, and C organic, to solution, and recrystallization of the sediment to an assemblage containing albitic plagioclase, quartz, pyrrhotite, and calcite. The δ 34S cdt values of dissolved H 2S varied from -10.9 to +4.3‰ during seawater-sediment interaction at 325 and 400°C and from -16.5 to -9.0‰ during Na-Ca-K-Cl fluid-sediment interaction at 325 and 375°C. In the absence of seawater SO 4, H 2S is derived from both the transformation of pyrite to pyrrhotite and S released during the degradation of organic matter. In the presence of seawater SO 4, reduction of SO 4 contributes directly to H 2S production. Sedimentary organic matter acts as the reducing agent during pyrite and SO 4 reduction. Requisite acidity for the reduction of SO 4 is provided by Mg fixation during early-stage sediment alteration and by albite and calcite formation in Mg-free solutions. Organically derived CH 4 was characterized by δ 13C pdb values ranging between -20.8 and -23.1‰, whereas δ 13C pdb values for dissolved C organic ranged between -14.8 and -17.7%. Mass balance calculations indicate that δ13C values for organically derived CO 2 were ≥ - 14.8%. Residual solid sedimentary organic C showed small (≤ 0.7‰) depletions in 13C relative to the starting sediment. The experimental results are consistent with the isotopic and chemical composition of natural hydrothermal fluids and minerals at Guaymas Basin and permit us to better constrain sources and sinks for C and S species in subseafloor

  1. Separately supported polymetallic reforming catalyst

    SciTech Connect

    Kresge, C. T.; Krishnamurthy, S.; McHale, W. D.

    1985-01-15

    There is provided, in accordance with the present invention, a catalyst composition made up of a mixture of two components, one component comprising a minor proportion of platinum and rhenium on a support and the second component comprising a minor proportion of iridium and rhenium on a separate support. A process for reforming a charge stock, such as naphtha, utilizing such catalyst is also provided.

  2. Photovoltaic concentrators

    NASA Astrophysics Data System (ADS)

    Boes, E. C.

    1980-01-01

    A status report on photovoltaic (PV) concentrators technology is presented. The major topics covered are as follows: (1) current PV concentrator arrays; designs, performances, and costs; (2) current PV concentrator array components; cells and cell assemblies, optical concentrators, support structures, tracking, and drive; (3) design of PV concentrator arrays; and (4) array manufacturing technology.

  3. Sn-polymetallic greisen-type deposits associated with late-stage rapakivi granites, Brazil: fluid inclusion and stable isotope characteristics

    NASA Astrophysics Data System (ADS)

    Bettencourt, Jorge S.; Leite, Washington B.; Goraieb, Claudio L.; Sparrenberger, Irena; Bello, Rosa M. S.; Payolla, Bruno L.

    2005-03-01

    Tin-polymetallic greisen-type deposits in the Itu Rapakivi Province and Rondônia Tin Province, Brazil are associated with late-stage rapakivi fluorine-rich peraluminous alkali-feldspar granites. These granites contain topaz and/or muscovite or zinnwaldite and have geochemical characteristics comparable to the low-P sub-type topaz-bearing granites. Stockworks and veins are common in Oriente Novo (Rondônia Tin Province) and Correas (Itu Rapakivi Province) deposits, but in the Santa Bárbara deposit (Rondônia Tin Province) a preserved cupola with associated bed-like greisen is predominant. The contrasting mineralization styles reflect different depths of formation, spatial relationship to tin granites, and different wall rock/fluid proportions. The deposits contain a similar rare-metal suite that includes Sn (±W, ±Ta, ±Nb), and base-metal suite (Zn-Cu-Pb) is present only in Correas deposit. The early fluid inclusions of the Correas and Oriente Novo deposits are (1) low to moderate-salinity (0-19 wt.% NaCl eq.) CO 2-bearing aqueous fluids homogenizing at 245-450 °C, and (2) aqueous solutions with low CO 2, low to moderate salinity (0-14 wt.% NaCl eq.), which homogenize between 100 and 340 °C. In the Santa Bárbara deposit, the early inclusions are represented by (1) low-salinity (5-12 wt.% NaCl eq.) aqueous fluids with variable CO 2 contents, homogenizing at 340 to 390 °C, and (2) low-salinity (0-3 wt.% NaCl eq.) aqueous fluid inclusions, which homogenize at 320-380 °C. Cassiterite, wolframite, columbite-tantalite, scheelite, and sulfide assemblages accompany these fluids. The late fluid in the Oriente Novo and Correas deposit was a low-salinity (0-6 wt.% NaCl eq.) CO 2-free aqueous solution, which homogenizes at (100-260 °C) and characterizes the sulfide-fluorite-sericite association in the Correas deposit. The late fluid in the Santa Bárbara deposit has lower salinity (0-3 wt.% NaCl eq.) and characterizes the late-barren-quartz, muscovite and kaolinite

  4. Elliptical concentrators.

    PubMed

    Garcia-Botella, Angel; Fernandez-Balbuena, Antonio Alvarez; Bernabeu, Eusebio

    2006-10-10

    Nonimaging optics is a field devoted to the design of optical components for applications such as solar concentration or illumination. In this field, many different techniques have been used to produce optical devices, including the use of reflective and refractive components or inverse engineering techniques. However, many of these optical components are based on translational symmetries, rotational symmetries, or free-form surfaces. We study a new family of nonimaging concentrators called elliptical concentrators. This new family of concentrators provides new capabilities and can have different configurations, either homofocal or nonhomofocal. Translational and rotational concentrators can be considered as particular cases of elliptical concentrators.

  5. Concentrating collectors

    SciTech Connect

    Not Available

    1981-06-01

    Selected specifications from sixteen concentrating collector manufacturers are tabulated. Eleven are linear parabolic trough collectors, and the others include slats, cylindrical trough, linear Fresnel lens, parabolic cylindrical Fresnel lens, and two point focus parabolic dish collectors. Also included is a brief discussion of the operating temperatures and other design considerations for concentrating collectors. (LEW)

  6. Concentrating Radioactivity

    ERIC Educational Resources Information Center

    Herrmann, Richard A.

    1974-01-01

    By concentrating radioactivity contained on luminous dials, a teacher can make a high reading source for classroom experiments on radiation. The preparation of the source and its uses are described. (DT)

  7. Concentrating Radioactivity

    ERIC Educational Resources Information Center

    Herrmann, Richard A.

    1974-01-01

    By concentrating radioactivity contained on luminous dials, a teacher can make a high reading source for classroom experiments on radiation. The preparation of the source and its uses are described. (DT)

  8. Steady-state distribution of metals among metallothionein and other cytosolic ligands and links to cytotoxicity in bivalves living along a polymetallic gradient.

    PubMed

    Giguère, Anik; Couillard, Yves; Campbell, Peter G C; Perceval, Olivier; Hare, Landis; Pinel-Alloul, Bernadette; Pellerin, Jocelyne

    2003-07-16

    The present study was designed to assess the environmental effects of metals in a field setting. We explored exposure-->bioaccumulation-->effects relationships in freshwater molluscs exposed to metals in their natural habitat. Indigenous floater mussels (Pyganodon grandis) were collected from ten limnologically similar lakes located along a Cd, Cu and Zn gradient. Ambient free-metal ion concentrations were estimated as a measure of metal exposure. Metallothionein (MT) was measured in mussel gills and metal partitioning among the various cytosolic protein pools was determined by size exclusion chromatography. Various biomarkers were also measured, including malondialdehyde (MDA) concentrations in the gills and in the digestive gland, glutathione-peroxidase and glutathione-reductase activities in the digestive gland, and lipid concentrations in the gonad. Cadmium and MT concentrations in the gill cytosol increased along the contamination gradient, but Cu and Zn levels were independent of the ambient free-metal ion concentrations. The distribution of Cd among the various cytosolic complexes remained quite constant: 80% in the MT-like pool, 7% in the low molecular weight pool (LMW<1.8 kDa) and 13% in the high molecular weight pool (HMW>18 kDa). For these chronically exposed molluscs there was thus no threshold exposure concentration above which spillover of Cd occurred from the MT pool to other cytosolic ligands. However, the presence of Cd in the LMW and HMW fractions suggests that metal detoxification was imperfect, i.e. that P. grandis was subject to some Cd-related stress at low chronic exposure concentrations. Consistent with this suggestion, MDA concentrations, an indicator of oxidative stress, increased with gill cytosolic Cd. In the digestive gland, MDA concentrations were unrelated to any of the measured metals, but glutathione-peroxidase and glutathione-reductase activities increased with gill cytosolic copper. We speculate that cytosolic Cu catalyses the

  9. Origin of the granites and related Sn and Pb-Zn polymetallic ore deposits in the Pengshan district, Jiangxi Province, South China: constraints from geochronology, geochemistry, mineral chemistry, and Sr-Nd-Hf-Pb-S isotopes

    NASA Astrophysics Data System (ADS)

    Xu, Bin; Jiang, Shao-Yong; Luo, Lan; Zhao, Kui-Dong; Ma, Liang

    2016-05-01

    The Pengshan Sn and Pb-Zn polymetallic deposits are located in the south margin of the Jiujiang-Ruichang (Jiurui) district of the Middle-Lower Yangtze River Metallogenic Belt in South China. Four large deposits include Huangjinwa, Zengjialong, Jianfengpo, and Zhangshiba, the former three are Sn-dominant deposits which occur as stratiform orebodies in the contact zones of the Pengshan granites and within the country rock strata, whereas Zhangshiba consists of stratiform Pb-Zn orebodies within the Precambrian metasedimentary strata. In this study, we present results on zircon U-Pb ages, major and trace elements, and mineral chemistry as well as Sr-Nd-Hf isotope data of the granites, Pb and S isotopes of both the Sn-dominant and Pb-Zn dominant deposits, and U-Pb dating of cassiterite from the Pengshan district. SHRIMP and LA-ICP-MS zircon U-Pb dating shows that the Pengshan granites were emplaced in the Early Cretaceous (129-128 Ma), which is in good agreement with the U-Pb dating (130-128 Ma) of cassiterite from the Jianfengpo Sn deposit. The Pengshan granites consist mainly of weakly peraluminous highly fractionated I-type affinity granitic rocks. Detailed elemental and isotopic data suggest that the granites formed by partial melting of Mesoproterozoic metamorphic basement materials with minor input of mantle-derived melts. The mineral chemistry of biotite demonstrates that the Pengshan granitic magma had a low oxygen fugacity, thereby precluding the tin dominantly partitioning into the rock-forming silicate minerals and favoring accumulation in the exsolved residual liquid during magma crystallization stages. Sulfur isotopes show a relatively heavy sulfur isotopic composition from 5.8 to 17.6 ‰, and no difference for sulfur isotopes between the Sn deposits (5.8-13.4 ‰, Huangjinwa, Zengjialong, Jianfengpo) and the Pb-Zn deposit (mostly 7.1-13.0 ‰, except for one 17.6 ‰, Zhangshiba). The sulfur isotope data of pyrite from the host sedimentary rocks show

  10. Origin of the granites and related Sn and Pb-Zn polymetallic ore deposits in the Pengshan district, Jiangxi Province, South China: constraints from geochronology, geochemistry, mineral chemistry, and Sr-Nd-Hf-Pb-S isotopes

    NASA Astrophysics Data System (ADS)

    Xu, Bin; Jiang, Shao-Yong; Luo, Lan; Zhao, Kui-Dong; Ma, Liang

    2017-03-01

    The Pengshan Sn and Pb-Zn polymetallic deposits are located in the south margin of the Jiujiang-Ruichang (Jiurui) district of the Middle-Lower Yangtze River Metallogenic Belt in South China. Four large deposits include Huangjinwa, Zengjialong, Jianfengpo, and Zhangshiba, the former three are Sn-dominant deposits which occur as stratiform orebodies in the contact zones of the Pengshan granites and within the country rock strata, whereas Zhangshiba consists of stratiform Pb-Zn orebodies within the Precambrian metasedimentary strata. In this study, we present results on zircon U-Pb ages, major and trace elements, and mineral chemistry as well as Sr-Nd-Hf isotope data of the granites, Pb and S isotopes of both the Sn-dominant and Pb-Zn dominant deposits, and U-Pb dating of cassiterite from the Pengshan district. SHRIMP and LA-ICP-MS zircon U-Pb dating shows that the Pengshan granites were emplaced in the Early Cretaceous (129-128 Ma), which is in good agreement with the U-Pb dating (130-128 Ma) of cassiterite from the Jianfengpo Sn deposit. The Pengshan granites consist mainly of weakly peraluminous highly fractionated I-type affinity granitic rocks. Detailed elemental and isotopic data suggest that the granites formed by partial melting of Mesoproterozoic metamorphic basement materials with minor input of mantle-derived melts. The mineral chemistry of biotite demonstrates that the Pengshan granitic magma had a low oxygen fugacity, thereby precluding the tin dominantly partitioning into the rock-forming silicate minerals and favoring accumulation in the exsolved residual liquid during magma crystallization stages. Sulfur isotopes show a relatively heavy sulfur isotopic composition from 5.8 to 17.6 ‰, and no difference for sulfur isotopes between the Sn deposits (5.8-13.4 ‰, Huangjinwa, Zengjialong, Jianfengpo) and the Pb-Zn deposit (mostly 7.1-13.0 ‰, except for one 17.6 ‰, Zhangshiba). The sulfur isotope data of pyrite from the host sedimentary rocks show

  11. Isotopic and geochemical constraints on lead and fluid sources of the Pbsbnd Znsbnd Ag mineralization in the polymetallic Tighza-Jbel Aouam district (central Morocco), and relationships with the geodynamic context

    NASA Astrophysics Data System (ADS)

    Rossi, Magali; Gasquet, Dominique; Cheilletz, Alain; Tarrieu, Leïla; Bounajma, Hassan; Mantoy, Tristan; Reisberg, Laurie; Deloule, Etienne; Boulvais, Philippe; Burnard, Pete

    2017-03-01

    The Wsbnd Au, Pbsbnd Znsbnd Ag, and Sbsbnd Ba mineralizations of the polymetallic Tighza-Jbel Aouam district (central Meseta, Morocco), are hosted in Paleozoic rocks surrounding late-Carboniferous granitic stocks. The Pbsbnd Znsbnd Ag Tighza deposit formed at 254 ± 16 Ma, and is clearly disconnected from the late-Variscan Wsbnd Au deposit (295-280 Ma). The Pbsbnd Znsbnd Ag mineralization precipitated from a complex hydrothermal fluid. It displays air-normalized 3He/4He ratio (0.018-0.103) typical of the upper crust. This crustal component is confirmed by the oxygen and carbon isotope compositions (δ18O = +19 to +25‰; δ13C = -3.6 to -11.2‰) and the ɛNd values (-4.84 to -9.01) of gangue carbonates, which show mixing of (i) fluids that have interacted with late-Carboniferous magmatic rocks, and (ii) fluids in equilibrium with the Paleozoic metasediments. In addition, the Pbsbnd Znsbnd Ag mineralization has 40Ar/36Ar values in the range 284-315 typical of a meteoric fluid. The radiogenic Pb isotopic compositions (207Pb/204Pb = 15.70-15.80 and 206Pb/204Pb = 18.30-18.50) suggest leaching of Pb from the surrounding Paleozoic metasediments and late-Variscan granites, whereas the low radiogenic signatures (207Pb/204Pb = 15.40 and 206Pb/204Pb = 18.05) provide evidence of a deeper source attributed to the lower crust. Crustal thinning related to extensional tectonics in late-Permian and Early-Triassic lead to high-K calc-alkaline to alkaline magmatic activity, which is evidenced by a dense SW-NE-trending dike network that pre-dated the Atlantic Ocean opening (early Liassic times). This magmatic event induced a regional heat flux increase that triggered the circulation of a complex hydrothermal fluid, which has a strong crustal component, but also a meteoric and a lower crustal components. The polymetallic district of Tighza-Jbel Aouam thus results from superposition of an intrusion related porphyry-gold mineralization (Wsbnd Au, 286 Ma) followed by a Pbsbnd Znsbnd Ag

  12. Origin of sulfur and crustal recycling of copper in polymetallic (Cu-Au-Co-Bi-U ± Ag) iron-oxide-dominated systems of the Great Bear Magmatic Zone, NWT, Canada

    NASA Astrophysics Data System (ADS)

    Acosta-Góngora, P.; Gleeson, S. A.; Samson, I. M.; Corriveau, L.; Ootes, L.; Jackson, S. E.; Taylor, B. E.; Girard, I.

    2017-06-01

    The Great Bear Magmatic Zone, in northwest Canada, contains numerous polymetallic mineral occurrences, prospects, and deposits of the iron oxide copper-gold deposit (IOCG) family. The mineralization is hosted by the Treasure Lake Group and igneous rocks of the Great Bear arc and was deposited concomitantly with the arc magmatism (ca. 1.88 to 1.87 Ga). In situ δ 34S (n = 48) and δ 65Cu (n = 79) analyses were carried out on ore-related sulfides from a number of these systems. The δ 34S values mainly vary between 0 and +5‰, consistent with derivation of sulfur from the mantle. Lower δ 34S values (-7.7 to +1.4‰) from the Sue-Dianne breccia may indicate SO2 disproportionation of a magmatic hydrothermal fluid. The δ 65Cu values vary between -1.2 and -0.3‰, and are lower than the igneous δ 65Cu range of values (0.0 ± 0.27‰). The S and Cu isotopic data are decoupled, which suggests that Cu (and possibly some S) was dissolved and remobilized from supracrustal rocks during early stages of alteration (e.g., sodic alteration) and then precipitated by lower temperature, more oxidizing fluids (e.g., Ca-Fe-K alteration). A limited fluid inclusion dataset and δ 13C and δ 18O values are also presented. The δ 18Ofluid values are consistent with a magmatic origin or a host-rock equilibrated meteoric water source, whereas the δ 13Cfluid values support a marine carbonate source. Combined, the S and Cu isotopic data indicate that while the emplacement of the Great Bear magmatic bodies may have driven fluid convection and may be the source of fluids and sulfur, metals such as Cu could have been recycled from crustal sources.

  13. Data Concentrator

    NASA Technical Reports Server (NTRS)

    Willett, Mike

    2015-01-01

    Orbital Research, Inc., developed, built, and tested three high-temperature components for use in the design of a data concentrator module in distributed turbine engine control. The concentrator receives analog and digital signals related to turbine engine control and communicates with a full authority digital engine control (FADEC) or high-level command processor. This data concentrator follows the Distributed Engine Controls Working Group (DECWG) roadmap for turbine engine distributed controls communication development that operates at temperatures at least up to 225 C. In Phase I, Orbital Research developed detailed specifications for each component needed for the system and defined the total system specifications. This entailed a combination of system design, compiling existing component specifications, laboratory testing, and simulation. The results showed the feasibility of the data concentrator. Phase II of this project focused on three key objectives. The first objective was to update the data concentrator design modifications from DECWG and prime contractors. Secondly, the project defined requirements for the three new high-temperature, application-specific integrated circuits (ASICs): one-time programmable (OTP), transient voltage suppression (TVS), and 3.3V. Finally, the project validated each design by testing over temperature and under load.

  14. Uranium Isotope Compositions of Mid-Proterozoic Organic-rich Mudrocks: Evidence for an Episode of Increased Ocean Oxygenation at ca. 1.36 Ga and Evaluation of the Effect of Post-Depositional Hydrothermal Fluid Flow

    NASA Astrophysics Data System (ADS)

    Kendall, B.; Yang, S.; Lu, X.; Zhang, F.; Zheng, W.

    2016-12-01

    The U isotope system represents a relatively new paleoredox proxy that can help trace the evolution of global ocean redox chemistry, but has rarely been applied to the Mid-Proterozoic. We report U isotope data for marine black shales of the early Mesoproterozoic Velkerri Formation (Roper Group) and late Paleoproterozoic Wollogorang Formation (Tawallah Group) from the McArthur Basin, Northern Australia. An average authigenic δ238U of 0.13 ± 0.04‰ (1SD; relative to standard CRM145) was obtained for six euxinic shales from a 1 m interval that previously yielded a precise Re-Os depositional age of 1361 ± 21 Ma. After correcting for a U isotope fractionation of 0.60-0.85‰ between seawater and open-ocean euxinic sediments, we infer that coeval global seawater had a δ238U of -0.47‰ to -0.72‰, which is 0.1-0.3‰ lighter than modern seawater (-0.40 ± 0.03‰). A U isotope mass-balance model suggests that anoxic marine environments accounted for 25-50% of the global oceanic U sink at 1.36 Ga, which is 3-7 times greater than today. The model suggests that a significant proportion, potentially even a majority, of the seafloor was not covered by anoxic waters. Hence, we infer that a significant extent of the ocean floor was covered by O2-bearing waters at 1.36 Ga. The O2 concentrations of those waters were not necessarily high, and a large expanse of weakly to mildly oxygenated deep waters is consistent with the U isotope data. Uranium isotope data from a 1 m interval in the lower Velkerri Formation, deposited at 1417 ± 29 Ma based on Re-Os geochronology, yield a greater estimate for the extent of ocean anoxia. Hence, the upper Velkerri Formation may capture a transient episode of increased ocean oxygenation. Previous Re-Os isotope data from black shales of the ca. 1.73 Ga Paleoproterozoic Wollogorang Formation yielded an erroneously young date of 1359 ± 150 Ma because hydrothermal fluids percolated through the Tawallah Group rocks at ca. 1640 Ma. Higher δ238U

  15. Concentric Rims

    NASA Image and Video Library

    2016-01-19

    This image captured by NASA 2001 Mars Odyssey spacecraft shows an unnamed crater near Acheron Fossae. The structure of this crater includes a central pit and several concentric rims. Radial grooves can be seen on the ejecta blanket surrounding the crater. Orbit Number: 61879 Latitude: 36.8829 Longitude: 232.325 Instrument: VIS Captured: 2015-11-25 21:21 http://photojournal.jpl.nasa.gov/catalog/PIA20240

  16. Factors affecting the partitioning of Cu, Zn and Pb in boulder coatings and stream sediments in the vicinity of a polymetallic sulfide deposit

    USGS Publications Warehouse

    Filipek, L.H.; Chao, T.T.; Carpenter, R.H.

    1981-01-01

    A sequential extraction scheme is utilized to determine the geochemical partitioning of Cu, Zn and Pb among hydrous Mn- and Fe-oxides, organics and residual crystalline silicates and oxides in the minus-80-mesh ( Fe-oxides > Mn-oxides; Zn, Mn-oxides {reversed tilde equals} organics > Fe-oxides; Pb, Fe-oxides > organics > Mn-oxides. In the sediments, organics are the most efficient scavengers of all three ore metals. These results emphasize the importance of organics as sinks for the ore metals, even in environments with high concentrations of Mn- and Fe-oxides. Of the ore metals, Zn appears to be the most mobile, and is partitioned most strongly into the coatings. However, anomaly contrast for hydromorphic Zn, normalized to the MnFe-oxide or organic content, is similar in sediments and coatings. Cu shows the highest anomaly on the boulder coatings, probably due to precipitation of a secondary Cu mineral. In contrast, detrital Pb in the pan concentrates shows a better anomaly than any hydromorphic Pb component. ?? 1981.

  17. Are the Element Budget and the Occurrence of Polymetallic Nodules influenced by Fluids Circulating through the Oceanic Crust or/and Sediments?

    NASA Astrophysics Data System (ADS)

    Heller, C.; Kuhn, T.

    2016-12-01

    Hydrothermal fluids can extract significant amounts of heat from oceanic lithosphere by lateral fluid flow through permeable basaltic crust of an age of up to 65 Ma. Fluid recharge and discharge occur at basement outcrops in between impermeable pelagic sediments. Recharge of oxic seawater causes upward oxygen diffusion into sediments overlying the permeable basalt in areas proximal to recharge sites. It is suggested that this oxygen have a strong impact on sediments and Mn nodules during fluid exposure time. The aim of this study is to investigate if and how fluid flow through oceanic crust influence the distribution and element budget of the Mn nodules. For that purpose, Mn nodules were examined which were collected during the research cruise SO240 in the equatorial NE Pacific at sites with and without faults in the upper basement and overlying sediments. Faults are thought to be preferred fluid pathways. Nodules were found on the sediment surface as well as in the sediment and consist of different nm- to µm-thick, dense and porous layers. The geochemical composition of bulk nodules and single nodule layers were determined by XRF, ICP-MS/OES and by high resolution analyses with EMPA and LA-ICP-MS. Dense layers have low Mn/Fe ratios (<4) and high concentrations of Co, Zr and REY, while porous layers are characterized by high Mn/Fe ratios (> 10) and high Ni+Cu and Li concentrations (Koschinsky et al., 2010; Kuhn et al., 2010). The different compositions depends on different formation processes of the layers. Dense layers are formed by element precipitation from oxygen rich seawater and/or pore water and are called hydrogenetic, while porous layers were formed by precipitation from almost oxygen-free (suboxic) pore water (Burns & Burns, 1978; Glasby, 2006) and are called diagenetic (Halbach et al., 1988). Preliminary results show that there are significant differences between the geochemical composition of nodules grown at sediment surface and those found within

  18. Quartz dissolution in organic-rich aqueous systems

    USGS Publications Warehouse

    Bennett, Philip C.

    1991-01-01

    Organic electrolytes are a common component of natural waters and are known to be important in many rock-water interactions. The influence of organic electrolytes on silica mobility, quartz solubility, and quartz dissolution kinetics, however, is less well understood. While there is mounting evidence supporting the presence of an aqueous organic-silica complex in natural waters, the significance of this species is difficult to characterize because of competing interactions in mixed inorganic-organic electrolyte environments. In the experiments reported here, the kinetics of quartz dissolution in dilute aqueous organic-acid solutions between 25 and 70°C were investigated to determine the influence of both organic and inorganic electrolytes.Batch-reactor dissolution experiments in inorganic and organic electrolyte solutions were designed to investigate the hypothesis that organic acids at circum-neutral pH accelerate the dissolution and increase the solubility of quartz in water. Results suggest that multi-functional organic acids such as citrate and oxalate accelerate quartz dissolution by decreasing the activation energy by approximately 20%. The increase in dissolution rate was accompanied by a 100% increase in apparent quartz solubility at 25°C. Experiments using inorganic electrolytes, in contrast, increase the rate of quartz dissolution without decreasing the activation energy, and without increasing solubility.From these data, a model for both a solution complex between dissolved organic acid and monomeric silicic acid, and an activated complex on quartz surfaces is proposed. The model suggests that dissolved organic compounds in natural waters at near-neutral pH and low temperatures are capable of accelerating the dissolution of quartz and increasing its solubility.

  19. Sulfur and carbon cycling in organic-rich marine sediments

    NASA Technical Reports Server (NTRS)

    Martens, C. S.

    1985-01-01

    Nearshore, continental shelf, and slope sediments are important sites of microbially mediated carbon and sulfur cycling. Marine geochemists investigated the rates and mechanisms of cycling processes in these environments by chemical distribution studies, in situ rate measurements, and steady state kinetic modeling. Pore water chemical distributions, sulfate reduction rates, and sediment water chemical fluxes were used to describe cycling on a ten year time scale in a small, rapidly depositing coastal basin, Cape Lookout Bight, and at general sites on the upper continental slope off North Carolina, U.S.A. In combination with 210 Pb sediment accumulation rates, these data were used to establish quantitative carbon and sulfur budgets as well as the relative importance of sulfate reduction and methanogeneis as the last steps in the degradation of organic matter.

  20. Association of organic-rich (domanikoid) sediments and evaporites

    SciTech Connect

    Shteyngol'ts, V.L.; Chaykin, V.G.; Batalin, Yu.V.; Stankevich, E.F.

    1986-07-01

    Major quantities of oil and gas occur in sedimentary basins containing evaporites, for example the Persian Gulf, the West Canadian basin, and the Dnepr-Donets depression. The relationship between oil and salt has attracted much attention. In the early stages of research, most geologists denied that there was any genetic significance, with the saline beds assigned only a passive covering or structural role. More recently, however, Zharkov, Peterson, Hight, Lotze, Floeger, and others have concluded that there are genetic bases for the relationships. This paper presents an interesting categorization of environments favorable for the deposition of both salts and petroleum-generating organic matter. 14 references.

  1. The Hydrocarbon Fingerprints of Organic-rich Shales

    NASA Astrophysics Data System (ADS)

    Davies, S. J.; Sommariva, R.; Blake, R.; Ortega, M.; Cuss, R. J.; Harrington, J.; Emmings, J.; Lovell, M.; Monks, P.

    2016-12-01

    Geological characterization of key source rocks and potential unconventional reservoirs from the UK Mississippian has shed new light on the heterogeneous character of shales (mudstones) and also on the mechanisms for preserving organic matter of different types and abundances. Sedimentological studies of these mudstones suggest that systematic variations in total organic carbon (TOC) content are related to the dominant sediment delivery process (hemipelagic suspension settling vs. sediment gravity flows). Questions remain, however, as to how the physical character and chemical composition (e.g. lithology, mineralogy, organic matter type, maturity and abundance) of a mudstone relates to the volume and type of hydrocarbon gas that could be released. Using novel proof-of-principle laboratory experiments, we demonstrate that it is possible to quantify, in real-time (second by second), methane and a wide range of non-methane hydrocarbons (NMHC) gases as they are released from a crushed mudstone sample. Real time measurements are undertaken using proton-transfer-reaction time-of-flight mass spectrometry (PTR- TOF- MS). The PTR technique is not sensitive to some classes of NHMC and the whole range of hydrocarbons is analyzed using thermal desorption gas chromatography mass spectrometry (TD- GC- MS). Our data indicate that NMHC gases (mostly alkanes and aromatics) are released with temperature and humidity-dependent release rates, which depend on the physio-chemical characteristics of the different hydrocarbons classes and on the mode of storage within the shale. Knowledge of the abundance of methane and the speciated NMHC, and how that relates to geological characteristics of a mudstone is important to understand both the source rock potential and the potential pollutants. Ultimately, we aim to link these results to the geomechanical properties of shales. We discuss the implications of our findings for the environment and for the industrial and commercial exploitation of source rocks and unconventional reservoirs.

  2. Mechanism of formation of concentrically laminated spherules: Implication to Randall’s plaque and stone formation

    PubMed Central

    Amos, Fairland F.; Dai, Lijun; Kumar, Rajendra; Khan, Saeed R.; Gower, Laurie B.

    2013-01-01

    We report on the formation of calcium phosphate multi-laminated spherules via a polymer-induced liquid-like precursor (PILP) process. In this non-classical crystallization route, the precipitation of liquid-like amorphous calcium phosphate (ACP) particles is promoted using anionic polypeptide additives, and these droplets coalesce to form globules that later crystallize into spherulites. During crystallization of the amorphous globules, the polymer additive, as well as the waters of hydration, is excluded ahead of the crystallization front, but some polymer becomes entrapped within diffusion-limited zones. This results in the formation of concentric laminations with layers of variable density from organic-rich inclusions. The striking resemblance of these spherules with the crystals of the Randall’s plaque and other laminated stones suggests that such biological structures may form via an amorphous precursor process as well. Given the organic-rich environment present in the urinary tract, one might expect a large amount of organic materials to become entrapped within the stratified zones of a forming stone during this type of solidification and transformation process. PMID:19066874

  3. Assessment of environmental and health risks in former polymetallic ore mining and smelting area, Slovakia: Spatial distribution and accumulation of mercury in four different ecosystems.

    PubMed

    Árvay, Július; Demková, Lenka; Hauptvogl, Martin; Michalko, Miloslav; Bajčan, Daniel; Stanovič, Radovan; Tomáš, Ján; Hrstková, Miroslava; Trebichalský, Pavol

    2017-10-01

    Former long-term mining and smelting of pollymetallic ores in the Middle Spiš area caused a serious contamination problem of the environment with heavy metals and metalloids, especially mercury (Hg). Several studies have reported concentration of Hg in the area but this paper provides first detailed characterization of Hg contamination of different environmental components in agricultural, forest, grassland and urban ecosystems. The ecosystems are in different distances from emission sources - former mercury and copper smelting plants in NE Slovakia. Total Hg content was studied in soil/substrate samples (n = 234) and characteristic biological samples (Athyrium filix-femina (L.) Roth, Macrolepiota procera (Scop.) Singer, Boletus edulis Bull., Cyanoboletus pulverulentus (Opat.) Gelardi, Vizzini & Simonini, Triticum aestivum (L.), Poa pratensis (L.)) (n = 234) collected in the above-mentioned ecosystems. The level of contamination and environmental risks were assessed by contamination factor (Cf), index of geoaccumulation (Igeo) and potential environmental risk index (PER). To determine the level of transition of Hg from abiotic to biotic environment, bioconcentration factor (BCF) was used. To determine a health risk resulting from regular and long-term consumption of the locally available species, the results of the Hg content were compared with the Provisional Tolerable Weekly Intake (PTWI) for Hg defined by World Health Organization. The results suggest that almost 63% of the area belong to the very high risk category and 80% of the sampling sites shown very high contamination factor. Geoaccumulation index showed that almost 30% of the area is very strongly contaminated and only 8% is not contaminated with Hg. Spearman's correlation relationship confirmed that the values of PER, BCF, Cf and Igeo decreased with an increasing distance from the pollution source. The percentage of contribution to PTWI ranged between 5.76-69.0% for adults and 11.5-138% for children

  4. Spatial heterogeneity of within-stream methane concentrations

    NASA Astrophysics Data System (ADS)

    Crawford, John T.; Loken, Luke C.; West, William E.; Crary, Benjamin; Spawn, Seth A.; Gubbins, Nicholas; Jones, Stuart E.; Striegl, Robert G.; Stanley, Emily H.

    2017-05-01

    Streams, rivers, and other freshwater features may be significant sources of CH4 to the atmosphere. However, high spatial and temporal variabilities hinder our ability to understand the underlying processes of CH4 production and delivery to streams and also challenge the use of scaling approaches across large areas. We studied a stream having high geomorphic variability to assess the underlying scale of CH4 spatial variability and to examine whether the physical structure of a stream can explain the variation in surface CH4. A combination of high-resolution CH4 mapping, a survey of groundwater CH4 concentrations, quantitative analysis of methanogen DNA, and sediment CH4 production potentials illustrates the spatial and geomorphic controls on CH4 emissions to the atmosphere. We observed significant spatial clustering with high CH4 concentrations in organic-rich stream reaches and lake transitions. These sites were also enriched in the methane-producing mcrA gene and had highest CH4 production rates in the laboratory. In contrast, mineral-rich reaches had significantly lower concentrations and had lesser abundances of mcrA. Strong relationships between CH4 and the physical structure of this aquatic system, along with high spatial variability, suggest that future investigations will benefit from viewing streams as landscapes, as opposed to ecosystems simply embedded in larger terrestrial mosaics. In light of such high spatial variability, we recommend that future workers evaluate stream networks first by using similar spatial tools in order to build effective sampling programs.

  5. Effects of different water storage procedures on the dissolved Fe concentration and isotopic composition of chemically contrasted waters from the Amazon River Basin.

    PubMed

    Mulholland, Daniel S; Poitrasson, Franck; Boaventura, Geraldo R

    2015-11-15

    Although recent studies have investigated the Fe isotopic composition of dissolved, colloidal and particulate phases from continental and oceanic natural waters, few efforts have been made to evaluate whether water sample storage and the separation of different pore-size fractions through filtration can cause any change to the Fe isotopic compositions. The present study investigates the possible biases introduced by different water storage conditions on the dissolved Fe concentration and isotopic composition of chemically different waters. Water samples were collected from an organic-rich river and from mineral particulate-rich rivers. Filtered and unfiltered water samples were stored either at room temperature or frozen at -18°C in order to assess possible biases due to (i) different water storage temperature, and (ii) storage of bulk (unfiltered) vs filtered water. Iron isotope measurements were performed by Multicollector Inductively Coupled Plasma Mass Spectrometry with a Thermo Electron Neptune instrument, after Fe purification using anion-exchange resins. Our data reveal that bulk water storage at room temperature without filtration produces minor changes in the dissolved Fe isotopic composition of mineral particulate-rich waters, but significant isotopic composition changes in organic-rich waters. In both cases, however, the impact of the different procedures on the Fe concentrations was strong. On the other hand, the bulk water stored frozen without filtration produced more limited changes in the dissolved Fe concentrations, and also on isotopic compositions, relative to the samples filtered in the field. The largest effect was again observed for the organic-rich waters. These findings suggest that a time lag between water collection and filtration may cause isotopic exchanges between the dissolved and particulate Fe fractions. When it is not possible to filter the samples in the field immediately after collection, the less detrimental approach is to

  6. The concentration and isotopic composition of osmium in the oceans

    SciTech Connect

    Sharma, M.; Papanastassiou, D.A.; Wasserburg, G.J.

    1997-08-01

    Osmium is one of the rarer elements in seawater. Analytical difficulties have previously prevented the direct measurement of the osmium concentration and isotopic composition in seawater. We report a chemical separation procedure that yields quantitative extraction of osmium standard and of osmium tracer by iron hydroxide precipitation from seawater doped with osmium standard, osmium tracer, and FeCl{sub 3}. The iron hydroxide precipitate is processed to extract osmium, using techniques developed for iron meteorites. Utilizing this procedure, water samples from the Pacific and Atlantic oceans were analyzed for osmium concentration and isotopic composition. Direct determination of the osmium concentration of seawater gives between 15 and 19 fM kg{sup -1}. Detailed experiments on different aliquots of one seawater sample from the North Atlantic Ocean, keeping the amounts of reagents constant, yield concentrations from 16 to 19 fM kg{sup -1}. The variability in concentration is outside the uncertainty introduced because of blanks and indicates a lack of full equilibration between the osmium tracer and seawater osmium. The most reliable osmium concentration of the North Atlantic deep ocean water is 19 fM kg {sup -1} with the {sup 187}Os/{sup 186}Os ratio being 8.7{+-}2 (2{sigma}). Detailed experiments on one seawater sample from the Central Pacific Ocean indicate that the most reliable osmium concentration of the deep ocean water from the Central Pacific is 19 fM kg{sup -1} with the {sup 187}Os/{sup 186}Os ratio being 8.7{+-}0.3 (2{sigma}). The directly measured osmium isotopic composition of the oceans is in good agreement with that obtained from the analysis of some rapidly accumulating organic rich sediments. A sample of ambient seawater around the Juan de Fuca Ridge gave {sup 187}Os/{sup 186}Os = 6.9{+-} 0.4. 42 refs., 6 figs., 4 tabs.

  7. Intramolecular energy transfer reactions in polymetallic

    SciTech Connect

    Petersen, J.

    1990-11-01

    This report is concerned with intramolecular, energy-transfer reactions. The concept of preparing synthetically a complex molecular species, capable of absorbing a photon at one metal center (antenna fragment), transferring that energy to a second metal center (reactive fragment) via a bridging ligand was first reported by our group in 1979. It is now apparent that a major emphasis in inorganic chemistry in the future will involve these types of molecular ensembles. Complexes discussed include Rh, Ru, and Cu complexes. 23 refs., 14 tabs.

  8. Groundwater nutrient concentrations near an incised midwestern stream: Effects of floodplain lithology and land management

    USGS Publications Warehouse

    Schilling, K.E.; Jacobson, P.

    2008-01-01

    It has been recognized that subsurface lithology plays an important role in controlling nutrient cycling and transport in riparian zones. In Iowa and adjacent states, the majority of alluvium preserved in small and moderate sized valleys consists of Holocene-age organic-rich, and fine-grained loam. In this paper, we describe and evaluate spatial and temporal patterns of lithology and groundwater nutrient concentrations at a riparian well transect across Walnut Creek at the Neal Smith National Wildlife Refuge in Jasper County, Iowa. Land treatment on one side of the stream reduced the grass cover to bare ground and allowed assessment of the effects of land management on nutrient concentrations. Results indicated that groundwater in Holocene alluvium is very nutrient rich with background concentrations of nitrogen, phosphorus and dissolved organic carbon that exceed many environmentally sensitive criteria. Average concentrations of ammonium exceeded 1 mg/l in several wells under grass cover whereas nitrate concentrations exceeded 20 mg/l in wells under bare ground. Phosphate concentrations ranged from 0.1 to 1.3 mg/l and DOC concentrations exceeded 5 mg/l in many wells. Denitrification, channel incision, land management and geologic age of alluvium were found to contribute to variable nutrient loading patterns at the site. Study results indicated that riparian zones of incised streams downcutting through nutrient-rich Holocene alluvium can potentially be a significant source of nutrient loadings to streams. ?? 2008 Springer Science+Business Media B.V.

  9. Concentrations of mercury, cadmium, lead and copper in fruiting bodies of edible mushrooms in an emission area of a copper smelter and a mercury smelter.

    PubMed

    Svoboda, L; Zimmermannová, K; Kalac, P

    2000-01-31

    Four metals were determined by AAS techniques in 56 samples of 23 wild mushroom species collected in a heavily polluted area in eastern Slovakia in 1997 and 1998. The area has been contaminated from historical polymetallic ores mining and smelting and by emissions from a mercury smelter between 1969 and 1993 and from a copper smelter since 1951. No significant differences in metal concentrations (P < 0.05) were found in four species when comparing the periods 1992-1993 and 1997-1998. Considerable contamination of most species was observed mainly for mercury and cadmium. The highest levels of mercury, up to 50 mg kg-1 dry matter, were found in Boletus reticulatus, Lycoperdon perlatum and Marasmius oreades, and of cadmium up to 20 mg kg-1 dry matter in Xerocomus chrysenteron and Lycoperdon perlatum. The latter species also had extremely high lead and copper concentrations in hundreds of milligrams per kilogram dry matter. Concentrations of mercury and copper in caps of four Boletaceae species were significantly (P < 0.05) higher than those in stipes.

  10. Thin solar concentrator with high concentration ratio

    NASA Astrophysics Data System (ADS)

    Lin, Jhe-Syuan; Liang, Chao-Wen

    2013-09-01

    Solar concentrators are often used in conjunction with III-V multi-junction solar cells for cost reduction and efficiency improvement purposes. High flux concentration ratio, high optical efficiency and high manufacture tolerance are the key features required for a successful solar concentrator design. This paper describes a novel solar concentrator that combines the concepts, and thus the advantages, of both the refractive type ad reflective type. The proposed concentrator design adopts the Etendue-cascading concept that allows the light beams from all the concentric annular entrance pupils to be collected and transferred to the solar cell with minimal loss. This concept enables the system to perform near its Etendue-Limit and have a high concentration ratio simultaneously. Thereby reducing the costs of solar cells and therefor achieves a better the per watts cost. The concentrator demonstrated has a thing aspect ratio of 0.19 with a zero back focal distance. The numerical aperture at the solar cell immersed inside the dielectric concentrator is as high as 1.33 achieving a unprecedented high optical concentration ratio design.

  11. Spatial heterogeneity of within-stream methane concentrations

    USGS Publications Warehouse

    Crawford, John T.; Loken, Luke C.; West, William E.; Crary, Benjamin; Spawn, Seth A.; Gubbins, Nicholas; Jones, Stuart E.; Striegl, Rob; Stanley, Emily H.

    2017-01-01

    Streams, rivers, and other freshwater features may be significant sources of CH4 to the atmosphere. However, high spatial and temporal variabilities hinder our ability to understand the underlying processes of CH4 production and delivery to streams and also challenge the use of scaling approaches across large areas. We studied a stream having high geomorphic variability to assess the underlying scale of CH4 spatial variability and to examine whether the physical structure of a stream can explain the variation in surface CH4. A combination of high-resolution CH4 mapping, a survey of groundwater CH4 concentrations, quantitative analysis of methanogen DNA, and sediment CH4 production potentials illustrates the spatial and geomorphic controls on CH4 emissions to the atmosphere. We observed significant spatial clustering with high CH4 concentrations in organic-rich stream reaches and lake transitions. These sites were also enriched in the methane-producing mcrA gene and had highest CH4 production rates in the laboratory. In contrast, mineral-rich reaches had significantly lower concentrations and had lesser abundances of mcrA. Strong relationships between CH4and the physical structure of this aquatic system, along with high spatial variability, suggest that future investigations will benefit from viewing streams as landscapes, as opposed to ecosystems simply embedded in larger terrestrial mosaics. In light of such high spatial variability, we recommend that future workers evaluate stream networks first by using similar spatial tools in order to build effective sampling programs.

  12. Theoretical maximum concentration factors for solar concentrators

    SciTech Connect

    Nicolas, R.O.; Duran, J.C.

    1984-11-01

    The theoretical maximum concentration factors are determined for different definitions of the factor for two-dimensional and three-dimensional solar concentrators that are valid for any source with nonuniform intensity distribution. Results are obtained starting from those derived by Winston (1970) for Lambertian sources. In particular, maximum concentration factors for three models of the solar-disk intensity distribution are calculated. 12 references.

  13. Flat high concentration devices

    SciTech Connect

    Minano, J.C.; Gonzalez, J.C.; Zanesco, I.

    1994-12-31

    During the last five years new concentrators achieving the theoretical maximum acceptance-angle-concentration product have appeared. In addition, some of these concentrators are very compact (concentrator depth/aperture diameter smaller than 1/3). The feasibility of these concentrators for photovoltaic applications is studied. It is concluded that these concentrators may be useful for high concentration cells (irradiance for maximum efficiency greater than 800 suns) if these cells have a small size (diameter smaller than 5 mm). The concentrators may provide for this case an acceptance angle of {approx} {+-}2.7 degrees with concentration factor around 1,000x and a concentrator depth 10 times the cell diameter. Instantaneous direct insolation and ambient temperature measurements of Madrid and a thermal model of the heat sink is used to calculate the annual electric energy output with which different concentration factors are compared. Concentration of 1,000x is close to the one giving the maximum annual electrical output.

  14. Photovoltaic concentrator initiative: Concentrator cell development

    SciTech Connect

    Wohlgemuth, J.H.; Narayanan, S.

    1993-05-01

    This project involves the development of a large-area, low-cost, high-efficiency concentrator solar cell for use in the Entech 22-sun linear-focus Fresnel lens concentrator system. The buried contact solar cell developed at the University of New South Wales was selected for this project. Both Entech and the University of New South Wales are subcontractors. This annual report presents the program efforts from November 1990 through December 1991, including the design of the cell, development of a baseline cell process, and presentation of the results of preliminary cell processing. Important results include a cell designed for operation in a real concentrator system and substitution of mechanical grooving for the previously utilized laser scribing.

  15. Air Data - Concentration Map

    EPA Pesticide Factsheets

    Make a map of daily concentrations over several days. The daily air quality can be displayed in terms of the Air Quality Index or in concentration ranges for certain PM species like organic carbon, nitrates, and sulfates.

  16. Photovoltaics. III - Concentrators

    NASA Astrophysics Data System (ADS)

    Backus, C. E.

    1980-02-01

    Photovoltaic concentration systems that redirect sunlight falling on a surface to a smaller solar-cell surface concentrating the intensity of sunlight many times are examined. It is noted that solar cells for concentrating systems must be designed for low internal resistance as well as for high sunlight intensities. Two designs of silicon cells are presented that perform well at high concentrations; these are interdigitated back-contact cells and vertical multijunction cells. Attention is given to heat tapping of reemitted light.

  17. Rheology of concentrated biomass

    Treesearch

    J.R. Samaniuk; J. Wang; T.W. Root; C.T. Scott; D.J. Klingenberg

    2011-01-01

    Economic processing of lignocellulosic biomass requires handling the biomass at high solids concentration. This creates challenges because concentrated biomass behaves as a Bingham-like material with large yield stresses. Here we employ torque rheometry to measure the rheological properties of concentrated lignocellulosic biomass (corn stover). Yield stresses obtained...

  18. Spatial and temporal variations in trace metal concentrations in surface sediments of the Marennes Oléron Bay. Relation to hydrodynamic forcing

    NASA Astrophysics Data System (ADS)

    Strady, Emilie; Kervella, Stéphane; Blanc, Gérard; Robert, Serge; Yves Stanisière, Jean; Coynel, Alexandra; Schäfer, Jörg

    2011-06-01

    Sediments quality assessment is of priority concern to provide a comprehensible overview of ecological and chemical state of an ecosystem. The Marennes-Oléron Bay, hosting the largest oyster production in France, is influenced by the historic polymetallic pollution of the Gironde Estuary. Despite, management efforts and decreasing emissions in the Gironde watershed, Cd levels in oysters from the bay are close to consumption limit (5 μg g -1 dw, EC no. 466/2001). In this context, the aim of the study was to assess the priority metal (Ni, Cu, Zn, As, Ag, Cd, Hg, Pb and Th) concentrations in sediment within the Bay, by investigating spatial and temporal distribution variations and the role of hydrodynamic forcing. For that we selected three sites (east, west and south) characterizing different environments of the Bay and we observed metal concentrations, grain size distribution, bed elevation and wave activities during a year survey. The sampling strategy pointed out both spatial and temporal metal concentrations variability in sediment. In general, metal enrichments were close to geochemical background. The eastern part of the Bay, largely influenced by the Charente river particulate deposition, presented constant concentrations over the survey. In contrast, in the western part, bed elevation was strongly influenced by hydrodynamic forcing especially wave activities, and metal distribution showed constant metal concentrations except very located Cd minor enrichment related to the Gironde influence via the Antioche Strait (north). The southern part was disconnected from the rest of the Bay and showed minor to very located moderately severe Cd enrichment, related to the Gironde water discharges via the Maumusson Strait (south). Thus, the multi-disciplinary approach was relevant to characterize the interactions between hydrodynamic forcing on the environment and sediments and their metal quality state which (i) were close to geochemical background over a year for Ni

  19. Recent trends in concentrated photovoltaics concentrators' architecture

    NASA Astrophysics Data System (ADS)

    Buljan, Marina; Mendes-Lopes, João; Benítez, Pablo; Miñano, Juan Carlos

    2014-01-01

    The field of concentrated photovoltaics (CPV) has met some remarkable advances in recent years. The continuous increase in conversion efficiency of multijunction solar cells and new advancements in optics have led to new demands and opportunities for optical design in CPV. This paper is a mini-review on current requirements for CPV optical design, and it presents some of the main trends in recent years on CPV systems architecture.

  20. Concentrating photovoltaic systems

    NASA Astrophysics Data System (ADS)

    Dupas, A.

    1982-11-01

    Various configurations for concentrating photovoltaic systems are described and their operating principles are explained. The effects of temperature and series resistance on system efficiency are discussed. As an example, the french family of photovoltaic concentrating systems, SOPHOCLE, is described. The SOPHOCLE family of generators is characterized by the use of a heliostat with altazimuth mounting and by the choice of medium concentration (C=45) by fresnel lenses on silicon cells.

  1. Strategies to Support Concentration

    ERIC Educational Resources Information Center

    Haines, Annette

    2017-01-01

    Annette Haines provides a comprehensive overview of concentration across the planes. She first lays the foundation for thinking about student engagement: It must be understood that concentration is found through the interest of the child, which is guided by the sensitive periods. When we understand the child's development in this way, we can offer…

  2. High concentration plasma-reduced plateletapheresis concentrates.

    PubMed

    Perseghin, Paolo

    2011-06-01

    Single-donor hyperconcentrated plateletapheresis (dry-platelets) collection has been introduced in the 90's as a part of the newly developed multi-component collection strategy. This approach allowed to safely collect multiple components from a single apheresis donation, i.e. RBC, FFP and/or plateletpheresis units. Dry-platelets are usually resuspended in additive solution to maintain an adequate pH during the storage period until use. Some concern existed about possible higher degrees of platelet activation in dry-platelets units when compared to standard concentration (1.0-1.6 × 10(6)/μL platelets) units and its possible correlation with lower in vivo efficiency and/or survival of the former units. Several authors investigated this specific issue, and dry-platelets units proved to be equally effective than standard concentration plateletpheresis units in recipients. The use of dry-platelets units may reduce (i) the risk of passive infusion of naturally occurring ABO-related hemolytic antibodies when donor O platelets are given to group A, B, or AB recipient, (ii) the risk of TRALI when multiparous donors undergo plateletpheresis. Furthermore, dry-platelet collection may allow for an increased amount of FFP sent to industry. Finally, hyperconcentrated platelet units may be used for "niche" indications, such as intrauterine platelet transfusion or, in case of autologous dry-platelet collection, for further freezing for long term storage in selected patients within onco-hematological settings.

  3. Uranium concentrations in asparagus

    SciTech Connect

    Tiller, B.L.; Poston, T.M.

    1992-05-01

    Concentrations of uranium were determined in asparagus collected from eight locations near and ten locations on the Hanford Site southcentral Washington State. Only one location (Sagemoor) had samples with elevated concentrations. The presence of elevated uranium in asparagus at Sagemoor may be explained by the elevated levels in irrigation water. These levels of uranium are comparable to levels previously reported upstream and downstream of the 300-FF-1 Operable Unit on the Hanford Site (0.0008 {mu}g/g), but were below the 0.020-{mu}g/g level reported for brush collected at Sagemoor in a 1982 study. Concentrations at all other onsite and offsite sample locations were considerably lower than concentrations reported immediately upstream and downstream of the 300-FF-1 Operable Unit. Using an earlier analysis of the uranium concentrations in asparagus collected from the Hanford Site constitutes a very small fraction of the US Department of Energy effective dose equivalent limit of 100 mrem.

  4. Concentration of Hydrogen Peroxide

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde F. (Inventor)

    2006-01-01

    Methods for concentrating hydrogen peroxide solutions have been described. The methods utilize a polymeric membrane separating a hydrogen peroxide solution from a sweep gas or permeate. The membrane is selective to the permeability of water over the permeability of hydrogen peroxide, thereby facilitating the concentration of the hydrogen peroxide solution through the transport of water through the membrane to the permeate. By utilizing methods in accordance with the invention, hydrogen peroxide solutions of up to 85% by volume or higher may be generated at a point of use without storing substantial quantities of the highly concentrated solutions and without requiring temperatures that would produce explosive mixtures of hydrogen peroxide vapors.

  5. Concentrating photovoltaic solar panel

    DOEpatents

    Cashion, Steven A; Bowser, Michael R; Farrelly, Mark B; Hines, Braden E; Holmes, Howard C; Johnson, Jr., Richard L; Russell, Richard J; Turk, Michael F

    2014-04-15

    The present invention relates to photovoltaic power systems, photovoltaic concentrator modules, and related methods. In particular, the present invention features concentrator modules having interior points of attachment for an articulating mechanism and/or an articulating mechanism that has a unique arrangement of chassis members so as to isolate bending, etc. from being transferred among the chassis members. The present invention also features adjustable solar panel mounting features and/or mounting features with two or more degrees of freedom. The present invention also features a mechanical fastener for secondary optics in a concentrator module.

  6. Nebulization Reflux Concentrator

    NASA Technical Reports Server (NTRS)

    Cofer, Wesley R., III; Collins, V. G.

    1986-01-01

    Nebulization reflux concentrator extracts and concentrates trace quantities of water-soluble gases for subsequent chemical analysis. Hydrophobic membrane and nebulizing nozzles form scrubber for removing trace quantities of soluble gases or other contaminants from atmosphere. Although hydrophobic membrane virtually blocks all transport of droplets, it offers little resistance to gas flow; hence, device permits relatively large volumes of gas scrubbed efficiently with very small volumes of liquid. This means analyzable quantities of contaminants concentrate in extracting solutions in much shorter times than with conventional techniques.

  7. Water Sample Concentrator

    ScienceCinema

    Idaho National Laboratory

    2016-07-12

    Automated portable device that concentrates and packages a sample of suspected contaminated water for safe, efficient transport to a qualified analytical laboratory. This technology will help safeguard against pathogen contamination or chemical and biolog

  8. High concentration dust monitor

    NASA Astrophysics Data System (ADS)

    Lilienfeld, P.

    1981-06-01

    The development, design, fabrication, and testing of a portable, self-contained prototype monitoring instrument capable of detecting and measuring airborne coal dust levels as concentrations in the range of 20 to 500 g/cu m is described. The output of the high concentration dust monitor is essentially independent of particle size and composition, with a response time of 10 seconds. Direct concentration readout as well as internal memory or recording capabilities are incorporated in the device. The operation of the instrument is based on direct sensing of the mass concentration of airborne dust by air-path beta radiation attenuation. The monitor is battery operated and incorporates a microprocessor that controls periodic automatic zero referencing, executes the mass computations, records the data for subsequent playback, and performs internal diagnostic checks.

  9. Glass for Solar Concentrators

    NASA Technical Reports Server (NTRS)

    Bouquet, F. L.

    1984-01-01

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

  10. Modeling of Solar Concentrators

    NASA Technical Reports Server (NTRS)

    Rockey, D. E.

    1984-01-01

    Algorithm developed for predicting power output, uniformity of intensity and operating temperature of concentrator-enhanced photovoltaic solar cell arrays. Optimum values for parameters such as reflector geometry found prior to constructing scale models for testing.

  11. Rheology of concentrated biomass

    NASA Astrophysics Data System (ADS)

    Samaniuk, J. R.; Wang, J.; Root, T. W.; Scott, C. T.; Klingenberg, D. J.

    2011-12-01

    Economic processing of lignocellulosic biomass requires handling the biomass at high solids concentration. This creates challenges because concentrated biomass behaves as a Bingham-like material with large yield stresses. Here we employ torque rheometry to measure the rheological properties of concentrated lignocellulosic biomass (corn stover). Yield stresses obtained using torque rheometry agree with those obtained using other rheometric methods, but torque rheometry can be used at much larger solids concentration (weight fractions of insoluble solids greater than 0.2). Yield stresses decrease with severity of hydrolysis, decrease when water-soluble polymers are added (for nonhydrolyzed biomass), and increase with particle length. Experimental results are qualitatively consistent with those obtained from particle-level simulations.

  12. Water Sample Concentrator

    SciTech Connect

    Idaho National Laboratory

    2009-07-21

    Automated portable device that concentrates and packages a sample of suspected contaminated water for safe, efficient transport to a qualified analytical laboratory. This technology will help safeguard against pathogen contamination or chemical and biolog

  13. Cryogenic flux-concentrator

    NASA Technical Reports Server (NTRS)

    Bailey, B. M.; Brechna, H.; Hill, D. A.

    1969-01-01

    Flux concentrator has high primary to secondary coupling efficiency enabling it to produce high magnetic fields. The device provides versatility in pulse duration, magnetic field strengths and power sources.

  14. Joined concentric tubes

    DOEpatents

    DeJonghe, Lutgard; Jacobson, Craig; Tucker, Michael; Visco, Steven

    2013-01-01

    Tubular objects having two or more concentric layers that have different properties are joined to one another during their manufacture primarily by compressive and friction forces generated by shrinkage during sintering and possibly mechanical interlocking. It is not necessary for the concentric tubes to display adhesive-, chemical- or sinter-bonding to each other in order to achieve a strong bond. This facilitates joining of dissimilar materials, such as ceramics and metals.

  15. Test bed concentrator mirrors

    NASA Technical Reports Server (NTRS)

    Argoud, M. J.

    1980-01-01

    The test bed concentrator (TBC) was des point focusing distributed receiver (PFDR) systems. The reflective surface of the concentrator was fabricated using mirror facet designs and techniques. The facets are made by bonding mirrored glass to spherically-conducted substrates. Several aspects of earlier work were reevaluated for application to the TBC: optimum glass block size, material selection, environmental test, optical characteristics, and reliability. A detailed explanation of tooling, substrate preparation, testing techniques, and mirror assembly is presented.

  16. METHOD OF ISOTOPE CONCENTRATION

    DOEpatents

    Spevack, J.S.

    1957-04-01

    An isotope concentration process is described which consists of exchanging, at two or more different temperature stages, two isotopes of an element between substances that are physically separate from each other and each of which is capable of containing either of the isotopes, and withdrawing from a point between at least two of the temperatare stages one of the substances containing an increased concentration of the desired isotope.

  17. Low cost concentrator

    NASA Technical Reports Server (NTRS)

    Bedard, R. J., Jr.; Overly, P.

    1981-01-01

    The key to concentrator cost effectiveness is the proper design of the reflector surface panels. The low cost concentrator reflective surface design is based on use of a thin, backsilvered mirror glass reflector bonded to a molded structural plastic substrate. This combination of reflective panel material offers excellent optical performance at low cost. The design approach, rationale for the selected configuration, and the development status are described. Reflective panel development and demonstration results are also presented.

  18. Test bed concentrator mirrors

    NASA Astrophysics Data System (ADS)

    Argoud, M. J.

    1980-05-01

    The test bed concentrator (TBC) was des point focusing distributed receiver (PFDR) systems. The reflective surface of the concentrator was fabricated using mirror facet designs and techniques. The facets are made by bonding mirrored glass to spherically-conducted substrates. Several aspects of earlier work were reevaluated for application to the TBC: optimum glass block size, material selection, environmental test, optical characteristics, and reliability. A detailed explanation of tooling, substrate preparation, testing techniques, and mirror assembly is presented.

  19. Advanced concentrator panels

    NASA Technical Reports Server (NTRS)

    Bell, D. M.; Bedard, R. J., Jr.

    1981-01-01

    The prototype fabrication of a lightweight, high-quality cellular glass substrate reflective panel for use in an advanced point-focusing solar concentrator was completed. The reflective panel is a gore shaped segment of an 11-m paraboloidal dish. The overall concentrator design and the design of the reflective panels are described. prototype-specific panel design modifications are discussed and the fabrication approach and procedure outlined.

  20. Interpreting serum risperidone concentrations.

    PubMed

    Boerth, Joel M; Caley, Charles F; Goethe, John W

    2005-02-01

    Risperidone is an atypical antipsychotic commonly used for treatment of schizophrenia and other psychotic disorders. Although therapeutic drug monitoring is not routine for any of the atypical antipsychotics, serum antipsychotic concentrations are measured routinely to assess treatment nonadherence. In humans, risperidone is metabolized by cytochrome P450 2D6 to 9-hydroxyrisperidone; together these constitute the active moiety. Dose-proportional increases in serum concentrations have not been reported for the parent drug, but have been reported for 9-hydroxyrisperidone and the active moiety (i.e., the combined concentrations of risperidone and 9-hydroxyrisperidone). We describe a 34-year-old Caucasian man of Sicilian descent with a history of schizophrenia, disorganized type. He was suspected to be noncompliant with his risperidone therapy. Initially, active moiety risperidone concentrations increased linearly with prescribed dosage increases. However, with continued increases, active moiety concentrations adjusted downward and remained 17-36% below anticipated levels. We propose a method for estimating target active moiety concentrations of risperidone based on dosage-a method that may be used to guide clinicians in assessing nonadherence to risperidone treatment.

  1. Hydrogen Peroxide Concentrator

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde F.

    2007-01-01

    A relatively simple and economical process and apparatus for concentrating hydrogen peroxide from aqueous solution at the point of use have been invented. The heart of the apparatus is a vessel comprising an outer shell containing tubular membranes made of a polymer that is significantly more permeable by water than by hydrogen peroxide. The aqueous solution of hydrogen peroxide to be concentrated is fed through the interstitial spaces between the tubular membranes. An initially dry sweep gas is pumped through the interiors of the tubular membranes. Water diffuses through the membranes and is carried away as water vapor mixed into the sweep gas. Because of the removal of water, the hydrogen peroxide solution flowing from the vessel at the outlet end is more concentrated than that fed into the vessel at the inlet end. The sweep gas can be air, nitrogen, or any other gas that can be conveniently supplied in dry form and does not react chemically with hydrogen peroxide.

  2. Photovoltaic solar concentrator

    DOEpatents

    Nielson, Gregory N.; Okandan, Murat; Resnick, Paul J.; Cruz-Campa, Jose Luis

    2012-12-11

    A photovoltaic solar concentrator is disclosed with one or more transverse-junction solar cells (also termed point contact solar cells) and a lens located above each solar cell to concentrate sunlight onto the solar cell to generate electricity. Piezoelectric actuators tilt or translate each lens to track the sun using a feedback-control circuit which senses the electricity generated by one or more of the solar cells. The piezoelectric actuators can be coupled through a displacement-multiplier linkage to provide an increased range of movement of each lens. Each lens in the solar concentrator can be supported on a frame (also termed a tilt plate) having three legs, with the movement of the legs being controlled by the piezoelectric actuators.

  3. Thermal cloak-concentrator

    NASA Astrophysics Data System (ADS)

    Shen, Xiangying; Li, Ying; Jiang, Chaoran; Ni, Yushan; Huang, Jiping

    2016-07-01

    For macroscopically manipulating heat flow at will, thermal metamaterials have opened a practical way, which possesses a single function, such as either cloaking or concentrating the flow of heat even though environmental temperature varies. By developing a theory of transformation heat transfer for multiple functions, here we introduce the concept of intelligent thermal metamaterials with a dual function, which is in contrast to the existing thermal metamaterials with single functions. By assembling homogeneous isotropic materials and shape-memory alloys, we experimentally fabricate a kind of intelligent thermal metamaterials, which can automatically change from a cloak (or concentrator) to a concentrator (or cloak) when the environmental temperature changes. This work paves an efficient way for a controllable gradient of heat, and also provides guidance both for arbitrarily manipulating the flow of heat and for efficiently designing similar intelligent metamaterials in other fields.

  4. Photovoltaic solar concentrator

    DOEpatents

    Nielson, Gregory N.; Gupta, Vipin P.; Okandan, Murat; Watts, Michael R.

    2016-03-15

    A photovoltaic solar concentrator is disclosed with one or more transverse-junction solar cells (also termed point contact solar cells) and a lens located above each solar cell to concentrate sunlight onto the solar cell to generate electricity. Piezoelectric actuators tilt or translate each lens to track the sun using a feedback-control circuit which senses the electricity generated by one or more of the solar cells. The piezoelectric actuators can be coupled through a displacement-multiplier linkage to provide an increased range of movement of each lens. Each lens in the solar concentrator can be supported on a frame (also termed a tilt plate) having three legs, with the movement of the legs being controlled by the piezoelectric actuators.

  5. Airborne agent concentration analysis

    DOEpatents

    Gelbard, Fred

    2004-02-03

    A method and system for inferring airborne contaminant concentrations in rooms without contaminant sensors, based on data collected by contaminant sensors in other rooms of a building, using known airflow interconnectivity data. The method solves a least squares problem that minimizes the difference between measured and predicted contaminant sensor concentrations with respect to an unknown contaminant release time. Solutions are constrained to providing non-negative initial contaminant concentrations in all rooms. The method can be used to identify a near-optimal distribution of sensors within the building, when then number of available sensors is less than the total number of rooms. This is achieved by having a system-sensor matrix that is non-singular, and by selecting that distribution which yields the lowest condition number of all the distributions considered. The method can predict one or more contaminant initial release points from the collected data.

  6. Concentrating photovoltaic technology

    SciTech Connect

    Edenburn, M.W.

    1984-01-01

    This paper will summarize the status and discuss likely future directions of photovoltaic concentrator technology. A current commercial Si cell module has a peak efficiency of 15.5%, and 17% has been reached with an experimental module. Advanced cells and module design improvements offer still higher efficiencies. Concentrator Fresnel lens array fields installed several years ago have all demonstrated very good electrical performance with little performance degradation. Fresnel lens arrays were commercially available and prices of $7/watt for installed one megawatt systems have been quoted. Cost projections predict that current technology concentrating PV arrays can be installed for less than $2/watt if they are manufactured in large, steady quantities. More advanced designs may cost even less.

  7. Recent Greenhouse Gas Concentrations

    DOE Data Explorer

    Blasing, T. J.

    2016-01-01

    Gases typically measured in parts per million (ppm), parts per billion (ppb) or parts per trillion (ppt) are presented separately to facilitate comparison of numbers. Global Warming Potentials (GWPs) and atmospheric lifetimes are from the Intergovernmental Panel on Climate Change (IPCC, 2013, Table 8.A.1), except for the atmospheric lifetime of carbon dioxide (CO2) which is explained in footnote 4. Additional material on greenhouse gases can be found in CDIAC's Reference Tools. To find out how CFCs, HFCs, HCFCs, and halons are named, see Name that compound: The numbers game for CFCs, HFCs, HCFCs, and Halons. Concentrations given apply to the lower 75-80 percent of the atmosphere, known as the troposphere. Sources of the current and preindustrial concentrations of the atmospheric gases listed in the table below are given in the footnotes. Investigators at the National Oceanic and Atmospheric Administration have provided the recent concentrations. Much of the data provided results from the work of various investigators at institutions other than CDIAC, and represent considerable effort on their part. We ask as a basic professional courtesy that you acknowledge the primary sources, indicated in the footnotes below, or in the links given in the footnotes. Concentrations of ozone and water vapor are spatially and temporally variable due to their short atmospheric lifetimes. A vertically and horizontally averaged water vapor concentration is about 5,000 ppm. Globally averaged water vapor concentration is difficult to measure precisely because it varies from one place to another and from one season to the next. This precludes a precise determination of changes in water vapor since pre-industrial time. However, a warmer atmosphere will likely contain more water vapor than at present. For a more detailed statement on water vapor from the National Oceanic and Atmospheric Administration, see the "water vapor" page at http://lwf.ncdc.noaa.gov/oa/climate/gases.html

  8. Solar radiation concentrator

    SciTech Connect

    Gravisse, P.

    1982-04-13

    A luminescent solar radiation concentrator is disclosed. Incident radiation of flux phi 1, and wavelength lambda 1, impinges enclosure wall v1 having a double index of refraction n1, n2 (Where n2>n1) and then is absorbed by cascade fluorescent concentrator/converter cl, which isotropically re-emits fluorescent radiation at wavelength lambda 2 and flux phi 2 (Where lambda 2> lambda 1, and phi 2> phi 1) which then is absorbed by a solar photovoltaic cell. The double index of refraction wall prevents escape of fluorescence radiation from the enclosure.

  9. Nebulization reflux concentrator

    NASA Technical Reports Server (NTRS)

    Collins, V. G.; Cofer, W. R., III

    1986-01-01

    A nebulization reflux concentrator for removing trace gas contaminants from a sample gas is described. Sample gas from a gas supply is drawn by a suction source into a vessel. The gas enters the vessel through an atomizing nozzle, thereby atomizing and entraining a scrubbing liquid solvent drawn through a siphon tube from a scrubbing liquid reservoir. The gas and entrained liquid rise through a concentrator and impinge upon a solvent phobic filter, whereby purified gas exits through the filter housing and contaminated liquid coalesces on the solvent phobic filter and falls into the reservoir.

  10. The effect of using different 0.45 μm filter membranes on 'dissolved' element concentrations in natural waters

    USGS Publications Warehouse

    Hall, G.E.M.; Bonham-Carter, G. F.; Horowitz, A.J.; Lum, K.; Lemieux, C.; Quemerais, B.; Garbarino, J.R.

    1996-01-01

    The effect of 4 different 0.45 ??m pore size filter membrane systems on the 'dissolved' concentration of 28 elements in 5 natural water samples of varying matrix is reported. In 3 of the 5 waters, consistently higher concentrations of most elements (minor and trace) are obtained using Nucleopore 47 mm filter and the cellulose acetate/nitrate 47 mm filter than those measured using the 142 mm cellulose nitrate MFS filter or the Gelman capsule 47 mm filter. These distinct and coherent patterns in elemental behaviour disappear for the other 2 samples, an organic-rich peat water of high suspended load and a mineralised sample high in Si and Ca. Thus the nature and degree of filtration artifacts is matrix-dependent. These trends are evident in both data sets produced by 2 independent laboratories using different instrumentation, techniques and calibrating procedures. The average relative standard deviation in elemental concentration across the 4 filter types is in the range 9-21%. The presence of such filtration artifacts must be considered in projects where, for example, seasonal variability of water composition is under examination, data from various sources are being merged or hydrogeochemical surveys are being conducted.

  11. Concentrating Tripartite Quantum Information.

    PubMed

    Streltsov, Alexander; Lee, Soojoon; Adesso, Gerardo

    2015-07-17

    We introduce the concentrated information of tripartite quantum states. For three parties Alice, Bob, and Charlie, it is defined as the maximal mutual information achievable between Alice and Charlie via local operations and classical communication performed by Charlie and Bob. We derive upper and lower bounds to the concentrated information, and obtain a closed expression for it on several classes of states including arbitrary pure tripartite states in the asymptotic setting. We show that distillable entanglement, entanglement of assistance, and quantum discord can all be expressed in terms of the concentrated information, thus revealing its role as a unifying informational primitive. We finally investigate quantum state merging of mixed states with and without additional entanglement. The gap between classical and quantum concentrated information is proven to be an operational figure of merit for mixed state merging in the absence of additional entanglement. Contrary to the pure state merging, our analysis shows that classical communication in both directions can provide an advantage for merging of mixed states.

  12. Dilution, Concentration, and Flotation

    ERIC Educational Resources Information Center

    Liang, Ling; Schmuckler, Joseph S.

    2004-01-01

    As both classroom teaching practice and literature show, many students have difficulties learning science concepts such as density. Here are some investigations that identify the relationship between density and floating through experimenting with successive dilution of a liquid, or the systematic change of concentration of a saltwater solution.…

  13. Solar concentrator/absorber

    NASA Technical Reports Server (NTRS)

    Von Tiesenhausen, G. F.

    1976-01-01

    Collector/energy converter, consisting of dual-slope optical concentrator and counterflow thermal energy absorber, is attached to multiaxis support structure. Efficient over wide range of illumination levels, device may be used to generate high temperature steam, serve as solar powered dryer, or power absorption cycle cooler.

  14. Offset paraboloidal solar concentrator

    NASA Technical Reports Server (NTRS)

    Chow, E. Y.

    1981-01-01

    Section of conventional paraboloid, offset from its major axis, is used as reflector in solar concentrator. Design increases solar gathering efficiency by 3 to 4 percent by eliminating shadowing and blocking of solar rays. In addition, reflector can be folded toward receiver, reducing wind-loading and making maintenance easier.

  15. Dilution, Concentration, and Flotation

    ERIC Educational Resources Information Center

    Liang, Ling; Schmuckler, Joseph S.

    2004-01-01

    As both classroom teaching practice and literature show, many students have difficulties learning science concepts such as density. Here are some investigations that identify the relationship between density and floating through experimenting with successive dilution of a liquid, or the systematic change of concentration of a saltwater solution.…

  16. Concentrating Tripartite Quantum Information

    NASA Astrophysics Data System (ADS)

    Streltsov, Alexander; Lee, Soojoon; Adesso, Gerardo

    2015-07-01

    We introduce the concentrated information of tripartite quantum states. For three parties Alice, Bob, and Charlie, it is defined as the maximal mutual information achievable between Alice and Charlie via local operations and classical communication performed by Charlie and Bob. We derive upper and lower bounds to the concentrated information, and obtain a closed expression for it on several classes of states including arbitrary pure tripartite states in the asymptotic setting. We show that distillable entanglement, entanglement of assistance, and quantum discord can all be expressed in terms of the concentrated information, thus revealing its role as a unifying informational primitive. We finally investigate quantum state merging of mixed states with and without additional entanglement. The gap between classical and quantum concentrated information is proven to be an operational figure of merit for mixed state merging in the absence of additional entanglement. Contrary to the pure state merging, our analysis shows that classical communication in both directions can provide an advantage for merging of mixed states.

  17. Lead-isotopic, sulphur-isotopic, and trace-element studies of galena from the Silesian-Cracow Zn-Pb ores, polymetallic veins from the Gory Swietokrzyskie MTS, and the Myszkow porphyry copper deposit, Poland

    USGS Publications Warehouse

    Church, S.E.; Vaughn, R.B.; Gent, C.A.; Hopkins, R.T.

    1996-01-01

    as indicated by the geologic evidence, the source rocks probably contained elevated concentrations of Zn and Pb (75-100 ppm), and relatively low concentrations of U and Th (2 and 8 ppm or less, respectively). The Carboniferous coal-bearing molasse rocks of the Upper Silesian Coal Basin are a prime candidate for such a source region. The presence of ammonia and acetate in the fluid inclusions (Viets et al., 1996a) also indicate that the Carboniferous coal-bearing molasse sequence in the Upper Silesian Coal Basin may have been a suitable pathway for the MVT ore fluids. The lead-isotopic homogeneity, when coupled with the sulfur-isotopic heterogeneity of the ores suggests that mixing of a single metal-bearing fluid with waters from separate aquifers containing variable sulfur-isotopic compositions in karsts in the Muschelkalk Formation of Middle Triassic age may have been responsible for the precipitation of the ores of the Silesian-Cracow district.

  18. The concentration and isotopic composition of osmium in the oceans

    NASA Astrophysics Data System (ADS)

    Sharma, M.; Papanastassiou, D. A.; Wasserburg, G. J.

    1997-08-01

    Osmium is one of the rarer elements in seawater. Analytical difficulties have previously prevented the direct measurement of the osmium concentration and isotopic composition in seawater. We report a chemical separation procedure that yields quantitative extraction of osmium standard and of osmium tracer by iron hydroxide precipitation from seawater doped with osmium standard, osmium tracer, and FeCl 3. The iron hydroxide precipitate is processed to extract osmium, using techniques developed for iron meteorites. Utilizing this procedure, water samples from the Pacific and Atlantic oceans were analyzed for osmium concentration and isotopic composition. Direct determination of the osmium concentration of seawater gives between 15 and 19 fM kg -1. Detailed experiments on different aliquots of one seawater sample from the North Atlantic Ocean, keeping the amounts of reagents constant, yield concentrations from 16 to 19 fM kg -1. The variability in concentration is outside the uncertainty introduced because of blanks and indicates a lack of full equilibration between the osmium tracer and seawater osmium. The most reliable osmium concentration of the North Atlantic deep ocean water is 19 fM kg -1 with the 187Os 186Os ratio being 8.7 ± 0.2 (2σ). Detailed experiments on one seawater sample from the Central Pacific Ocean indicate that the most reliable osmium concentration of the deep ocean water from the Central Pacific is 19 fM kg -1 with the 187Os 186Os ratio being 8.7 ± 0.3 (2σ). The directly measured osmium isotopic composition of the oceans is in good agreement with that obtained from the analysis of some rapidly accumulating organic rich sediments ( Ravizza and Turekian, 1992). A sample of ambient seawater around the Juan de Fuca Ridge gave 187Os 186Os= 6.9 ± 0.4. This is distinctly lower than the deep-sea water value and may reflect local hydrothermal activity or some analytical difficulty with this sample. The osmium isotopic composition of the deep oceans

  19. Measurement of Relative Dissolved Gas Concentrations Using Underwater Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Bell, R. J.; Toler, S.; van Amerom, F. H.; Wenner, P.; Hall, M.; Edkins, J.; Gassig, S.; Short, R.; Byrne, R.

    2004-12-01

    The deployment of underwater mass spectrometer (UMS) systems in marine and lacustrine environments has provided chemical data of exceptional temporal and spatial resolution. UMS instruments operate moored, tethered, remotely, or autonomously, allowing users to customize deployments to suit a wide variety of situations. The ability to collect and analyze real-time data enables prompt, intelligent sampling decisions based on observed analyte distributions. UMS systems can simultaneously detect a wide variety of analytes generated by biological, chemical, physical, geothermal and anthropogenic activities. A polydimethylsiloxane (PDMS) membrane separates the sample-stream from the spectrometer's vacuum chamber. This membrane is selective against water and charged species, yet highly permeable to volatile organic compounds (VOC) and simple gases. Current detection limits for dissolved gases and VOCs are on the order of ppm and ppb respectively. Semi-quantitative proof-of-concept applications have included horizontal mapping of gas gradients, characterization of geothermal vent water, and observation of dissolved gas profiles. Horizontal gradients in dissolved gas concentrations were determined in Lake Maggiore, St Petersburg, Florida. The UMS was positioned on a remotely-guided surface vehicle, and real-time gas concentration data were transmitted to shore via wireless ethernet. Real-time observations allowed intensive sampling of areas with strong gas gradients. Oxygen and CO2 exhibited patchy distributions and their concentrations varied inversely, presumably in response to biological activity. The UMS signal for methane depended on the instrument's proximity to organic rich sediments. Geothermal vent water was characterized while the UMS was deployed in Yellowstone Lake, Wyoming, on a tethered Eastern Oceanics remotely operated vehicle (ROV). Observations of dissolved vent-gas compositions were obtained to depths of 30m. Distinct differences in dissolved vent

  20. Scattering Solar Thermal Concentrators

    SciTech Connect

    Giebink, Noel C.

    2015-01-31

    This program set out to explore a scattering-based approach to concentrate sunlight with the aim of improving collector field reliability and of eliminating wind loading and gross mechanical movement through the use of a stationary collection optic. The approach is based on scattering sunlight from the focal point of a fixed collection optic into the confined modes of a sliding planar waveguide, where it is transported to stationary tubular heat transfer elements located at the edges. Optical design for the first stage of solar concentration, which entails focusing sunlight within a plane over a wide range of incidence angles (>120 degree full field of view) at fixed tilt, led to the development of a new, folded-path collection optic that dramatically out-performs the current state-of-the-art in scattering concentration. Rigorous optical simulation and experimental testing of this collection optic have validated its performance. In the course of this work, we also identified an opportunity for concentrating photovoltaics involving the use of high efficiency microcells made in collaboration with partners at the University of Illinois. This opportunity exploited the same collection optic design as used for the scattering solar thermal concentrator and was therefore pursued in parallel. This system was experimentally demonstrated to achieve >200x optical concentration with >70% optical efficiency over a full day by tracking with <1 cm of lateral movement at fixed latitude tilt. The entire scattering concentrator waveguide optical system has been simulated, tested, and assembled at small scale to verify ray tracing models. These models were subsequently used to predict the full system optical performance at larger, deployment scale ranging up to >1 meter aperture width. Simulations at an aperture widths less than approximately 0.5 m with geometric gains ~100x predict an overall optical efficiency in the range 60-70% for angles up to 50 degrees from normal. However, the

  1. Cyclindrical concentrators as a limit case of torodial concentrators

    SciTech Connect

    Minano, J.C.

    1984-06-15

    Cylindrical concentrators are viewed as a limit case of torodial concentrators with the purpose of applying to them some results obtained for axisymmetrical optical systems. This enables us to obtain easily the directional intercept factor of a cyclindrical nonimaging concentrator called the Ideal Tubular Concentrator. A useful tool for designing new cylindrical concentrators is also derived.

  2. Concentric Split Flow Filter

    NASA Technical Reports Server (NTRS)

    Stapleton, Thomas J. (Inventor)

    2015-01-01

    A concentric split flow filter may be configured to remove odor and/or bacteria from pumped air used to collect urine and fecal waste products. For instance, filter may be designed to effectively fill the volume that was previously considered wasted surrounding the transport tube of a waste management system. The concentric split flow filter may be configured to split the air flow, with substantially half of the air flow to be treated traveling through a first bed of filter media and substantially the other half of the air flow to be treated traveling through the second bed of filter media. This split flow design reduces the air velocity by 50%. In this way, the pressure drop of filter may be reduced by as much as a factor of 4 as compare to the conventional design.

  3. Concentration through large advection

    NASA Astrophysics Data System (ADS)

    Aleja, D.; López-Gómez, J.

    2014-11-01

    In this paper we extend the elegant results of Chen, Lam and Lou [6, Section 2], where a concentration phenomenon was established as the advection blows up, to a general class of adventive-diffusive generalized logistic equations of degenerate type. Our improvements are really sharp as we allow the carrying capacity of the species to vanish in some subdomain with non-empty interior. The main technical devices used in the derivation of the concentration phenomenon are Proposition 3.2 of Cano-Casanova and López-Gómez [5], Theorem 2.4 of Amann and López-Gómez [1] and the classical Harnack inequality. By the relevance of these results in spatial ecology, complete technical details seem imperative, because the proof of Theorem 2.2 of [6] contains some gaps originated by an “optimistic” use of Proposition 3.2 of [5]. Some of the general assumptions of [6] are substantially relaxed.

  4. Electrolyte Concentrates Treat Dehydration

    NASA Technical Reports Server (NTRS)

    2009-01-01

    Wellness Brands Inc. of Boulder, Colorado, exclusively licensed a unique electrolyte concentrate formula developed by Ames Research Center to treat and prevent dehydration in astronauts returning to Earth. Marketed as The Right Stuff, the company's NASA-derived formula is an ideal measure for athletes looking to combat dehydration and boost performance. Wellness Brands also plans to expand with products that make use of the formula's effective hydration properties to help treat conditions including heat stroke, altitude sickness, jet lag, and disease.

  5. Test Bed Concentrator (TBC)

    NASA Technical Reports Server (NTRS)

    Goldberg, V. R.

    1980-01-01

    A point focussing concentrator design adapted from an existing communications antenna for use in a solar test bed application is described. The structure design, configured for use with JPL's spherical radius mirror panels, made no attempt toward optimization. The key objectives of stiffness, pointing accuracy, and timely delivery were exceeded. The system weight is approximately 16,000 Kg (36,000 lbs) and has a calculated 1 sigma system error of 0.03 degrees.

  6. Concentrated Solar Thermoelectric Power

    SciTech Connect

    Chen, Gang; Ren, Zhifeng

    2015-07-09

    The goal of this project is to demonstrate in the lab that solar thermoelectric generators (STEGs) can exceed 10% solar-to-electricity efficiency, and STEGs can be integrated with phase-change materials (PCM) for thermal storage, providing operation beyond daylight hours. This project achieved significant progress in many tasks necessary to achieving the overall project goals. An accurate Themoelectric Generator (TEG) model was developed, which included realistic treatment of contact materials, contact resistances and radiative losses. In terms of fabricating physical TEGs, high performance contact materials for skutterudite TE segments were developed, along with brazing and soldering methods to assemble segmented TEGs. Accurate measurement systems for determining device performance (in addition to just TE material performance) were built for this project and used to characterize our TEGs. From the optical components’ side, a spectrally selective cermet surface was developed with high solar absorptance and low thermal emittance, with thermal stability at high temperature. A measurement technique was also developed to determine absorptance and total hemispherical emittance at high temperature, and was used to characterize the fabricated spectrally selective surfaces. In addition, a novel reflective cavity was designed to reduce radiative absorber losses and achieve high receiver efficiency at low concentration ratios. A prototype cavity demonstrated that large reductions in radiative losses were possible through this technique. For the overall concentrating STEG system, a number of devices were fabricated and tested in a custom built test platform to characterize their efficiency performance. Additionally, testing was performed with integration of PCM thermal storage, and the storage time of the lab scale system was evaluated. Our latest testing results showed a STEG efficiency of 9.6%, indicating promising potential for high performance concentrated STEGs.

  7. Modeling of concentrated suspensions

    NASA Astrophysics Data System (ADS)

    van den Brule, B. H. A. A.; Jongschaap, R. J. J.

    1991-03-01

    The constitutive equation of a concentrated suspension of spherical particles in a Newtonian medium is derived. To this end the method of local volume averaging is employed. To calculate the contribution of the particles to the stress tensor it is assumed that the stress generated in the interstitial holes between the particles is negligible compared to the stress generated in !he narrow gaps separating the particles. The use of the resulting expression is demonstrated with two examples on a cubical arrangement of particles: pure shear and simple shear. Furthermore, the validity of the lubrication approximation employed in this work is checked against the results derived by Nunan and Keller for periodic suspensions.

  8. METHOD OF ISOTOPE CONCENTRATION

    DOEpatents

    Taylor, T.I.; Spindel, W.

    1960-02-01

    A method of concentrating N/sup 15/ in a liquid is described. Gaseous nitric oxide and at least one liquid selected from the group consisting of the aqueous oxyacids and oxides of nitrogen, wherein the atomic ratio of oxygen to nitrogen is greater than unity, are brought into intimate contact to cause an enrichment of the liquid and a depletion of the gas in N/sup 15/. The liquid is, thereafter, reacted with sulfur dioxide to produce a gas contuining nitric oxide. The gas contuining nitric oxide is then continuously passed in countercurrent contact with the liquid to cause further enrichment of the liquid.

  9. Fixed solar energy concentrator

    SciTech Connect

    Houghton, A.J.; Knasel, T.M.

    1981-01-20

    An apparatus for the concentration of solar energy upon a fixed array of solar cells is disclosed. A transparent material is overlayed upon the cell array, and a diffuse reflective coating is applied to the surface area of the transparent medium in between cells. Radiant light, which reflects through the transparent layer and does not fall directly incident to a cell surface is reflected by the coating layer in an approximate cosine pattern. Thereafter, such light undergoes internal reflection and rediffusion until subsequently it either strikes a solar cell surface or is lost through the upper surface of the transparent material.

  10. Concentric layer ramjet fuel

    SciTech Connect

    Burdette, G.W.; Francis, J.P.

    1988-03-08

    This patent describes a solid fuel ramjet grain comprising concentric layers of solid ramjet fuel having a perforation therethrough along the center axis of the grain. The performation is connected to a combustion after-chamber. The solid ramjet fuel layers comprises a pure hydroxyl-terminated polybutadiene hydrocarbon fuel or a mixture of a hydroxyl-terminated polybutadiene hydrocarbon fuel and from about 5 to about 60 percent by weight of an additive to increase the fuel regression rate selected from the group consisting of magnesium, boron carbide, aluminum, and zirconium such that, when buried in the operation of the ramjet, each fuel layer produces a different level of thrust.

  11. Concentrating Solar Power Systems

    NASA Astrophysics Data System (ADS)

    Pitz-Paal, R.

    2017-07-01

    Development of Concentrating Solar Power Systems has started about 40 years ago. A first commercial implementation was performed between 1985 and 1991 in California. However, a drop in gas prices caused a longer period without further deployment. It was overcome in 2007 when new incentive schemes for renewables in Spain and the US enabled a commercial restart. In 2016, almost 100 commercial CSP plants with more than 5GW are installed worldwide. This paper describes the physical background of CSP technology, its technical characteristics and concepts. Furthermore, it discusses system performances, cost structures and the expected advancement.

  12. Plutonium in Concentrated Solutions

    SciTech Connect

    Clark, Sue B.; Delegard, Calvin H.

    2002-08-01

    Complex, high ionic strength media are used throughout the plutonium cycle, from its processing and purification in nitric acid, to waste storage and processing in alkaline solutions of concentrated electrolytes, to geologic disposal in brines. Plutonium oxidation/reduction, stability, radiolysis, solution and solid phase chemistry have been studied in such systems. In some cases, predictive models for describing Pu chemistry under such non-ideal conditions have been developed, which are usually based on empirical databases describing specific ion interactions. In Chapter 11, Non-Ideal Systems, studies on the behavior of Pu in various complex media and available model descriptions are reviewed.

  13. Vapor concentration monitor

    DOEpatents

    Bayly, John G.; Booth, Ronald J.

    1977-01-01

    An apparatus for monitoring the concentration of a vapor, such as heavy water, having at least one narrow bandwidth in its absorption spectrum, in a sample gas such as air. The air is drawn into a chamber in which the vapor content is measured by means of its radiation absorption spectrum. High sensitivity is obtained by modulating the wavelength at a relatively high frequency without changing its optical path, while high stability against zero drift is obtained by the low frequency interchange of the sample gas to be monitored and of a reference sample. The variable HDO background due to natural humidity is automatically corrected.

  14. Benchmarking concentrating photovoltaic systems

    NASA Astrophysics Data System (ADS)

    Duerr, Fabian; Muthirayan, Buvaneshwari; Meuret, Youri; Thienpont, Hugo

    2010-08-01

    Integral to photovoltaics is the need to provide improved economic viability. To achieve this goal, photovoltaic technology has to be able to harness more light at less cost. A large variety of concentrating photovoltaic concepts has provided cause for pursuit. To obtain a detailed profitability analysis, a flexible evaluation is crucial for benchmarking the cost-performance of this variety of concentrating photovoltaic concepts. To save time and capital, a way to estimate the cost-performance of a complete solar energy system is to use computer aided modeling. In this work a benchmark tool is introduced based on a modular programming concept. The overall implementation is done in MATLAB whereas Advanced Systems Analysis Program (ASAP) is used for ray tracing calculations. This allows for a flexible and extendable structuring of all important modules, namely an advanced source modeling including time and local dependence, and an advanced optical system analysis of various optical designs to obtain an evaluation of the figure of merit. An important figure of merit: the energy yield for a given photovoltaic system at a geographical position over a specific period, can be calculated.

  15. Optical oxygen concentration monitor

    DOEpatents

    Kebabian, P.

    1997-07-22

    A system for measuring and monitoring the concentration of oxygen uses as a light source an argon discharge lamp, which inherently emits light with a spectral line that is close to one of oxygen`s A-band absorption lines. In a preferred embodiment, the argon line is split into sets of components of shorter and longer wavelengths by a magnetic field of approximately 2,000 Gauss that is parallel to the light propagation from the lamp. The longer wavelength components are centered on an absorption line of oxygen and thus readily absorbed, and the shorter wavelength components are moved away from that line and minimally absorbed. A polarization modulator alternately selects the set of the longer wavelength, or upshifted, components or the set of the shorter wavelength, or downshifted, components and passes the selected set to an environment of interest. After transmission over a path through that environment, the transmitted optical flux of the argon line varies as a result of the differential absorption. The system then determines the concentration of oxygen in the environment based on the changes in the transmitted optical flux between the two sets of components. In alternative embodiments modulation is achieved by selectively reversing the polarity of the magnetic field or by selectively supplying the magnetic field to either the emitting plasma of the lamp or the environment of interest. 4 figs.

  16. Optical oxygen concentration monitor

    DOEpatents

    Kebabian, Paul

    1997-01-01

    A system for measuring and monitoring the concentration of oxygen uses as a light source an argon discharge lamp, which inherently emits light with a spectral line that is close to one of oxygen's A-band absorption lines. In a preferred embodiment, the argon line is split into sets of components of shorter and longer wavelengths by a magnetic field of approximately 2000 Gauss that is parallel to the light propagation from the lamp. The longer wavelength components are centered on an absorption line of oxygen and thus readily absorbed, and the shorter wavelength components are moved away from that line and minimally absorbed. A polarization modulator alternately selects the set of the longer wavelength, or upshifted, components or the set of the shorter wavelength, or downshifted, components and passes the selected set to an environment of interest. After transmission over a path through that environment, the transmitted optical flux of the argon line varies as a result of the differential absorption. The system then determines the concentration of oxygen in the environment based on the changes in the transmitted optical flux between the two sets of components. In alternative embodiments modulation is achieved by selectively reversing the polarity of the magnetic field or by selectively supplying the magnetic field to either the emitting plasma of the lamp or the environment of interest.

  17. Non-tracking solar concentrator with a high concentration ratio

    DOEpatents

    Hinterberger, Henry

    1977-01-01

    A nontracking solar concentrator with a high concentration ratio is provided. The concentrator includes a plurality of energy absorbers which communicate with a main header by which absorbed heat is removed. Undesired heat flow of those absorbers not being heated by radiant energy at a particular instant is impeded, improving the efficiency of the concentrator.

  18. Concentrating Solar Power

    SciTech Connect

    Weinstein, Lee A.; Loomis, James; Bhatia, Bikram; Bierman, David M.; Wang, Evelyn N.; Chen, Gang

    2015-12-09

    Solar energy is a bountiful renewable energy resource: the energy in the sunlight that reaches Earth in an hour exceeds the energy consumed by all of humanity in a year.(1) While the phrase “solar energy conversion” probably brings photovoltaic (PV) cells to mind first, PV is not the only option for generating electricity from sunlight. Another promising technology for solar energy conversion is solar–thermal conversion, commonly referred to as concentrating solar power (CSP).(2) The first utility-scale CSP plants were constructed in the 1980s, but in the two decades that followed, CSP saw little expansion.(3, 4) More recent years, however, have seen a CSP renaissance due to unprecedented growth in the adoption of CSP.(3, 5) Photographs of two operating CSP plants, a parabolic trough collector plant and a central receiver (or “power tower”), are shown here.

  19. Concentric differential gearing arrangement

    NASA Technical Reports Server (NTRS)

    Zeiger, R. J.; Gerdts, J. C. (Inventor)

    1974-01-01

    Two input members and two concentric rotatable output members are interconnected by a planetary gear arrangement. The first input drives directly the first output. The second input engages a carrier having the planetary gears affixed thereto. Rotation of the carriage causes rotation of the central sun gear of the planetary gear system. The sun gear is journaled to the carriage and is drivingly connected to the second output through a direction reversing set of bevel gears. The first input drive member includes a ring gear drivingly connected to the planetary gears for driving the second output member in the same direction and by the same amount as the first output member. Motion of the first input results in equal motion of the two outputs while input motion of the second input results in movement of the second output relative to the first output. This device is useful where non-interacting two-axis control of remote gimbaled systems is required.

  20. Concentrating solar thermal power.

    PubMed

    Müller-Steinhagen, Hans

    2013-08-13

    In addition to wind and photovoltaic power, concentrating solar thermal power (CSP) will make a major contribution to electricity provision from renewable energies. Drawing on almost 30 years of operational experience in the multi-megawatt range, CSP is now a proven technology with a reliable cost and performance record. In conjunction with thermal energy storage, electricity can be provided according to demand. To date, solar thermal power plants with a total capacity of 1.3 GW are in operation worldwide, with an additional 2.3 GW under construction and 31.7 GW in advanced planning stage. Depending on the concentration factors, temperatures up to 1000°C can be reached to produce saturated or superheated steam for steam turbine cycles or compressed hot gas for gas turbine cycles. The heat rejected from these thermodynamic cycles can be used for sea water desalination, process heat and centralized provision of chilled water. While electricity generation from CSP plants is still more expensive than from wind turbines or photovoltaic panels, its independence from fluctuations and daily variation of wind speed and solar radiation provides it with a higher value. To become competitive with mid-load electricity from conventional power plants within the next 10-15 years, mass production of components, increased plant size and planning/operating experience will be accompanied by technological innovations. On 30 October 2009, a number of major industrial companies joined forces to establish the so-called DESERTEC Industry Initiative, which aims at providing by 2050 15 per cent of European electricity from renewable energy sources in North Africa, while at the same time securing energy, water, income and employment for this region. Solar thermal power plants are in the heart of this concept.

  1. Pushing concentration of stationary solar concentrators to the limit.

    PubMed

    Winston, Roland; Zhang, Weiya

    2010-04-26

    We give the theoretical limit of concentration allowed by nonimaging optics for stationary solar concentrators after reviewing sun- earth geometry in direction cosine space. We then discuss the design principles that we follow to approach the maximum concentration along with examples including a hollow CPC trough, a dielectric CPC trough, and a 3D dielectric stationary solar concentrator which concentrates sun light four times (4x), eight hours per day year around.

  2. Pushing concentration of stationary solar concentrators to the limit.

    PubMed

    Winston, Roland; Zhang, Weiya

    2010-04-26

    We give the theoretical limit of concentration allowed by nonimaging optics for stationary solar concentrators after reviewing sun-earth geometry in direction cosine space. We then discuss the design principles that we follow to approach the maximum concentration along with examples including a hollow CPC trough, a dielectric CPC trough, and a 3D dielectric stationary solar concentrator which concentrates sun light four times (4x), eight hours per day year around.

  3. Methane Concentrations and Biogeochemistry in Lake Sediments from Stordalen Mire, Sub-Arctic Sweden

    NASA Astrophysics Data System (ADS)

    Halloran, M.; DeStasio, J.; Erickson, L.; Johnson, J. E.; Varner, R. K.; Setera, J.; Prado, M. F.; Wik, M.; Crill, P. M.

    2013-12-01

    Lake sediments are an important global carbon sink of both allochthonous and autochthonous inputs. However, lakes are also known to emit carbon in gaseous form, most often as methane (CH4) or carbon dioxide (CO2), which are potent greenhouse gases. As northern latitudes warm, it is increasingly important to understand these gases and the sediments that store them. In July of 2013 we took 48 cores at 16 sites throughout three lakes surrounding a mire underlain by degrading permafrost in sub-arctic Sweden. The goal was to characterize the sedimentology and geochemistry of the lake sediments to better understand the production, distribution, and flux of CO2 and CH4 from these lakes. Villasjön is a shallow lake less than 1.5 meters deep, Mellan Harrsjön has a maximum depth of 7 meters and is stream-fed, and Inre Harrsjön has a maximum depth of 5 meters and is connected to Mellan Harrsjön. Published radiocarbon dates suggest that all three lakes formed approximately 3400 years ago. At each sample site, we retrieved 2 to 4 cores from the lake bottom, approximately 40-80 cm in length. The cores were sub-sampled for measurements of bulk TOC, TC, TN, TS, and CaCO3 (by difference) using a CHNS Elemental Analyzer, and grain size using a laser particle size analyzer. Headspace CO2 and CH4 by gas chromatography and infrared gas analysis (IRGA) yielded production rates and CH4 sediment concentrations. Dissolved inorganic carbon (DIC) from porewater extractions were analyzed using IRGA and stable carbon isotopes of DIC were analyzed via a Quantum Cascade Laser. The recovered sediments in the cores from all three lakes were composed of three layers: an upper layer of organic rich sediment (30-40 cm thick), a middle transition layer of mixed organic and lithogenic materials (5-10 cm thick), and a deep layer of grey lithogenic clay with less organic carbon (of variable thickness). Preliminary results from the 12 Villasjön sites indicate that CH4 is present and produced from the

  4. Evidence of historical mining inferred from metal concentration of alluvial sediments in the Bernese Alps

    NASA Astrophysics Data System (ADS)

    Carvalho, Filipe; Schulte, Lothar

    2017-04-01

    Metal pollution is normally associated with modern day industrialization. However, evidences of anthropogenic metal pollution date back to the Palaeolithic, were the domestication of fire contributed to an increase of trace metals released from the burning wood. Large-scale metal pollution started during the Roman period with the increase of mining and smelting activities. The production of metals during this period was quite rudimentary and highly polluting, contributing to a raise of metal concentrations in the atmosphere and subsequently in sediments and soils. Towards the modern period, production methods were improved, especially since the industrial revolution, but continued to release pollutants to the environment. The aim of this study is to identify periods of increased mining activity though the analysis of sedimentary records. For this purpose, we study the geochemical response of trace metals in sedimentary cores from the Aare and Lütschine delta plains, located at the Bernese Alps. The focus of this analysis is the detection of metal concentration anomalies from the last 3000 years. The analysis is based on the X-Ray Fluorescence (AVATECH XRF core scanner) response of the chemical elements copper (Cu), zinc (Zn) and lead (Pb) contained in eight cores with depths down to 10 meter. All data was filtered in order to remove the noise from natural processes such as the increase of trace metal concentrations in organic rich horizons and to select the highest peaks of these metals. Results show similar trends in all the analysed cores and indicate three major pulses of trace metal concentration during the Roman Period, Early Medieval Age and a general increase of metal concentration during the Modern era, which can evidence mining and smelting activities. Periods of lower trace metal concentrations and shifts in concentration trends relate accurately with central Europe social and economic transitions, migratory events and significant demographic variations

  5. Spatial distribution patterns of molybdenum (Mo) concentrations in potable groundwater in Northern Jordan.

    PubMed

    Al Kuisi, Mustafa; Al-Hwaiti, Mohammad; Mashal, Kholoud; Abed, Abdulkader M

    2015-03-01

    -oxide, which releases substantial adsorbed Mo concentrations. Secondly, there is oxidation of Mo into dissolved forms in sulfide organic-rich system.

  6. Microbial production of natural gas from coal and organic-rich shale

    USGS Publications Warehouse

    Orem, William

    2013-01-01

    Natural gas is an important component of the energy mix in the United States, producing greater energy yield per unit weight and less pollution compared to coal and oil. Most of the world’s natural gas resource is thermogenic, produced in the geologic environment over time by high temperature and pressure within deposits of oil, coal, and shale. About 20 percent of the natural gas resource, however, is produced by microorganisms (microbes). Microbes potentially could be used to generate economic quantities of natural gas from otherwise unexploitable coal and shale deposits, from coal and shale from which natural gas has already been recovered, and from waste material such as coal slurry. Little is known, however, about the microbial production of natural gas from coal and shale.

  7. An Adsorption Capacity Study of Supercritical CO2 on Zeolite, Illite and Organic-Rich Shales

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Prasad, M.

    2016-12-01

    CO2 injection into reservoirs will change the state of stress in both reservoir and caprock formations due to poro-mechanical, thermal and chemical effects. As a result of the induced stress, the caprock can be mechanically damaged, pre-existing sealing faults and fractures can be re-activated, or new fracture systems can be created. It is the main objective of this study to determine the behavior of intact and fractured caprocks when exposed to supercritical CO2 at elevated pressures, including the characterization of the physical, chemical and geomechanical processes associated with fluid flow and storage in these systems. Hereby, an envisioned experimental setup allows high pressure, super-critical CO2 adsorption and desorption isotherm measurements on powdered rock samples is designed. Zeolite, illite and shale samples with different maturity levels are used as adsorbent to perform CO2 adsorption experiment to study the corresponding adsorption capacities.

  8. Sulfur geochemistry of organic-rich sediments from Mud Lake, Florida, USA

    USGS Publications Warehouse

    Bates, A.L.; Spkker, E.C.; Hatcher, P.G.; Stout, S.A.; Weintraub, V.C.

    1995-01-01

    The cores include the upper 4 m of sediment, which consist of four major horizons based on petrographic analyses of the organic material. Systematic changes in the isotopic composition of sedimentary disulfide and organic sulfur coincide with variations in the sulfur species and vegetation types. The transition to sapropel is accompanied by a large negative shift in disulfide ??34S- values, consistent with an increase in sulfate availability and a slower rate of sulfate reduction. -from Authors

  9. Comparison of three preservation techniques for slowing dissolution of calcareous nannofossils in organic rich sediments

    USGS Publications Warehouse

    Seefelt, Ellen L.; Self-Trail, Jean; Schultz, Arthur P.

    2015-01-01

    In an attempt to halt or reduce dissolution of calcareous nannofossils in organic and/or pyrite-rich sediments, three different methods of short-term storage preservation were tested for efficacy: vacuum packing, argon gas replacement, and buffered water. Abundance counts of calcareous nannofossil assemblages over a six month period showed that none of the three preservation methods were consistently effective in reducing assemblage loss due to dissolution. In most cases, the control slides made at the drill site had more abundant calcareous nannofossil assemblages than those slides made from sediments stored via vacuum packing, argon gas replacement, or buffered water. Thin section and XRD analyses showed that in most cases, <1% pyrite was needed to drive the oxidation-reduction reaction that resulted in dissolution, even in carbonate-rich sediments.

  10. Analysis of metalliferous, organic-rich shales of Pennsylvanian age in the midcontinent

    SciTech Connect

    Glascock, M.D.; Cruse, A.M.; Coveney, R.M. Jr.

    1996-12-31

    The chemistry of Pennsylvanian-age shales has long been of interest to geologists and geochemists. Pennsylvanian-age shales in the midcontinental United States, which vary in color from light gray to pitch black, are present in a thin layer averaging 70-cm thickness over an area of {approximately}600 000 km{sup 2}. The shales were deposited during the Middle and Upper Pennsylvanian periods ({approximately}291 to 302 million yr ago) when the midcontinent was covered by a shallow sea. In many instances, the shales are anomalously enriched to near-ore grade levels in a variety of heavy metals including molybdenum (ranging from 100 to 2500 ppm), zinc (ranging from 200 ppm to 3%), uranium (ranging from 50 to 1000 ppm), vanadium (ranging from 200 to 3000 ppm), selenium (ranging from 25 to 600 ppm), and others. As a result of their widespread occurrence, these metalliferous shales are of environmental concern as possible sources of heavy metals for groundwater pollution. On the other hand, some of the highly carbonaceous black shales may be beneficial as absorbers of certain environmentally toxic elements such as molybdenum, selenium, vanadium, and uranium. Finally, geochemists are interested in developing petrogenetic models to explain depositional variations of the shales because these variations reflect shifts in redox conditions combined with post-depositional alteration occurring during diagenesis. This report describes the use of neutron activation analysis for the investigation of shales.

  11. Correlation of resource plays and biodiversity patterns: accumulation of organic-rich shale tracks taxonomic turnover

    USGS Publications Warehouse

    Eoff, Jennifer D.

    2012-01-01

    Similar paleogeographic and paleotectonic settings characterize most self-sourced shale hydrocarbon plays. Their deposition occurred within similar orders of magnitude of eustatic events and during geologic periods characterized by “warm” (or transitional) climates and calcitic seas. In addition, the stratigraphic occurrence of shale plays parallels certain historical patterns of marine metazoan biodiversity. Such strong agreement among several correlation tools elucidates why these resources may be limited to discrete intervals of geological time. Correlation of self-sourced shale with biodiversity trends indicates that the factors controlling the deposition of marine organic matter may not be independent of those that induced taxonomic turnover. Paleoecological changes promoted accumulation and preservation of Type II kerogen. Deposition of self-sourced shale appears to correspond to reductions in absolute biodiversity and declining percentages of bioturbating taxa, with concomitant increases in proportions of pelagic taxa relative to infaunal and epifaunal organisms. Whereas upwelling and anoxia may have contributed to the deposition of kerogen in source rocks throughout much of the sedimentary record, diminished consumption of biomass by benthic metazoans likely augmented the preservation of organic carbon during deposition of this shale type. Rapid tectonic-plate reconfiguration induced coeval events, creating basins with sufficiently high rates of accommodation creation necessary to preserve additional organic material accumulating as the heterotrophic benthos suffered in response to rapidly changing environments. Combining sea-level curves, paleogeography, climate, and seawater chemistry provides a first-order approximation of the distribution of potential self-sourced shale in the geologic record. A model that predicts the stratigraphic distribution of self-sourced-shale deposition can aid in exploration of continuous hydrocarbon accumulations in self-sourced reservoirs globally.

  12. Microbial colonization of basaltic glasses in hydrothermal organic-rich sediments at Guaymas Basin

    PubMed Central

    Callac, Nolwenn; Rommevaux-Jestin, Céline; Rouxel, Olivier; Lesongeur, Françoise; Liorzou, Céline; Bollinger, Claire; Ferrant, Antony; Godfroy, Anne

    2013-01-01

    Oceanic basalts host diverse microbial communities with various metabolisms involved in C, N, S, and Fe biogeochemical cycles which may contribute to mineral and glass alteration processes at, and below the seafloor. In order to study the microbial colonization on basaltic glasses and their potential biotic/abiotic weathering products, two colonization modules called AISICS (“Autonomous in situ Instrumented Colonization System”) were deployed in hydrothermal deep-sea sediments at the Guaymas Basin for 8 days and 22 days. Each AISICS module contained 18 colonizers (including sterile controls) filled with basaltic glasses of contrasting composition. Chemical analyses of ambient fluids sampled through the colonizers showed a greater contribution of hydrothermal fluids (maximum temperature 57.6°C) for the module deployed during the longer time period. For each colonizer, the phylogenetic diversity and metabolic function of bacterial and archaeal communities were explored using a molecular approach by cloning and sequencing. Results showed large microbial diversity in all colonizers. The bacterial distribution was primarily linked to the deployment duration, as well as the depth for the short deployment time module. Some 16s rRNA sequences formed a new cluster of Epsilonproteobacteria. Within the Archaea the retrieved diversity could not be linked to either duration, depth or substrata. However, mcrA gene sequences belonging to the ANME-1 mcrA-guaymas cluster were found sometimes associated with their putative sulfate-reducers syntrophs depending on the colonizers. Although no specific glass alteration texture was identified, nano-crystals of barite and pyrite were observed in close association with organic matter, suggesting a possible biological mediation. This study gives new insights into the colonization steps of volcanic rock substrates and the capability of microbial communities to exploit new environmental conditions. PMID:23986754

  13. A laboratory evaluation of the sorption of oil sands naphthenic acids on organic rich soils.

    PubMed

    Janfada, Arash; Headley, John V; Peru, Kerry M; Barbour, S L

    2006-01-01

    The adsorption characteristics of oil sands tailings pond water (OSTPW)-derived naphthenic acids on soils was determined using a batch partitioning method. The adsorption isotherms were found to be linear in all cases. All tests were conducted at 4 degrees C, and at a pH of 8.0 +/- 0.4, which reflects the pH of a tailings settling facility near Fort McMurray, AB. The adsorption characteristics of the naphthenic acids in a synthetic groundwater (SGW) solution was compared to that of the mixture in Milli-Q water. In the presence of SGW, the adsorption coefficient (K(d)) of the mixture of naphthenic acids on soil 1 with a higher organic carbon fraction (f(oc)) was an order of magnitude higher than that observed with the same soil and the Milli-Q water mixture, increasing from 1.9 +/- 0.2 (mL/g) to 17.8 +/- 1.5 (mL/g). The adsorption coefficient of the mixture of naphthenic acids on soil 2, with a lower f(oc), was also observably higher in the SGW mixture, increasing from 1.3 +/- 0.15 (mL/g) to 3.7 +/- 0.2 (mL/g). The relative fractional abundance of the individual naphthenic acids was plotted in order to determine the presence of preferential sorption between individual species within the mixture. It was found that for all Z families (where Z is a measure of the number of rings), naphthenic acids within the carbon number range of 13 to 17 showed preferential sorption. The mixture in SGW showed more pronounced sorption relative to naphthenic acid mixture in Milli-Q water. The results indicate that mixtures of naphthenic acids sorb strongly to soils and that adsorption would be an important attenuating mechanism in groundwater transport. Furthermore, preferential sorption of the individual naphthenic acids is important from a toxicity stand point since different naphthenic acid species have varying degrees of toxicity.

  14. Intra-platformal organic-rich facies of the Alpine Triassic

    SciTech Connect

    Burchell, M.T.

    1988-08-01

    During the Middle and Late Triassic, large areas of the Alpine-Mediterranean region were blanketed by carbonate-platform systems that developed prior to the initiation of major rifting that ultimately produced the Ligurian Tethys Ocean. Field studies reveal that the stratigraphic record of these platforms includes a number of locally developed beds, in particular of Ladinian and late Norian-Rhaetian age, characterized by the preferential preservation of organic carbon in a range of facies, from subtidal right through to stromatolitic units conventionally referred to as inter/supratidal environments. This heightened carbon preservation is most strikingly developed in Ladinian and Norian-Rhaetian deposits of intraplatformal depressions with limited area (up to 1,000 km/sup 2/). These successions can approach 500 m thick and commonly consist of dark interbedded shales, limestones, and/or dolomite with 1 to 5% organic carbon, depending on carbonate dilution. With hydrogen indices up to 500 mg HC/g and S/sub 2/ pyrolysis yields in the range of 5-20 kg/MT, they clearly have considerable bulk petroleum source potential. In condensed sections these values may be greatly exceeded. The carbon-rich sequences were usually associated with Mesozoic structural highs which received relatively thin post-Triassic cover and as a consequence were commonly pushed into the oil window in the latest flysch phases, i.e., post-Alpine deformation. Thus not only were the source horizons surrounded by abundant carbonate reservoirs, but also any secondary migration should have occurred at a time when potential structural traps were stable.

  15. Microbial colonization of basaltic glasses in hydrothermal organic-rich sediments at Guaymas Basin.

    PubMed

    Callac, Nolwenn; Rommevaux-Jestin, Céline; Rouxel, Olivier; Lesongeur, Françoise; Liorzou, Céline; Bollinger, Claire; Ferrant, Antony; Godfroy, Anne

    2013-01-01

    Oceanic basalts host diverse microbial communities with various metabolisms involved in C, N, S, and Fe biogeochemical cycles which may contribute to mineral and glass alteration processes at, and below the seafloor. In order to study the microbial colonization on basaltic glasses and their potential biotic/abiotic weathering products, two colonization modules called AISICS ("Autonomous in situ Instrumented Colonization System") were deployed in hydrothermal deep-sea sediments at the Guaymas Basin for 8 days and 22 days. Each AISICS module contained 18 colonizers (including sterile controls) filled with basaltic glasses of contrasting composition. Chemical analyses of ambient fluids sampled through the colonizers showed a greater contribution of hydrothermal fluids (maximum temperature 57.6°C) for the module deployed during the longer time period. For each colonizer, the phylogenetic diversity and metabolic function of bacterial and archaeal communities were explored using a molecular approach by cloning and sequencing. Results showed large microbial diversity in all colonizers. The bacterial distribution was primarily linked to the deployment duration, as well as the depth for the short deployment time module. Some 16s rRNA sequences formed a new cluster of Epsilonproteobacteria. Within the Archaea the retrieved diversity could not be linked to either duration, depth or substrata. However, mcrA gene sequences belonging to the ANME-1 mcrA-guaymas cluster were found sometimes associated with their putative sulfate-reducers syntrophs depending on the colonizers. Although no specific glass alteration texture was identified, nano-crystals of barite and pyrite were observed in close association with organic matter, suggesting a possible biological mediation. This study gives new insights into the colonization steps of volcanic rock substrates and the capability of microbial communities to exploit new environmental conditions.

  16. Workplace Concentration of Immigrants

    PubMed Central

    Andersson, Fredrik; García-Pérez, Mónica; Haltiwanger, John; McCue, Kristin; Sanders, Seth

    2014-01-01

    Casual observation suggests that in most U.S. urban labor markets, immigrants have more immigrant coworkers than native-born workers do. While seeming obvious, this excess tendency to work together has not been precisely measured, nor have its sources been quantified. Using matched employer–employee data from the U.S. Census Bureau Longitudinal Employer-Household Dynamics (LEHD) database on a set of metropolitan statistical areas (MSAs) with substantial immigrant populations, we find that, on average, 37% of an immigrant’s coworkers are themselves immigrants; in contrast, only 14% of a native-born worker’s coworkers are immigrants. We decompose this difference into the probability of working with compatriots versus with immigrants from other source countries. Using human capital, employer, and location characteristics, we narrow the mechanisms that might explain immigrant concentration. We find that industry, language, and residential segregation collectively explain almost all the excess tendency to work with immigrants from other source countries, but they have limited power to explain work with compatriots. This large unexplained compatriot component suggests an important role for unmeasured country-specific factors, such as social networks. PMID:25425452

  17. Concentric tube support assembly

    DOEpatents

    Rubio, Mark F.; Glessner, John C.

    2012-09-04

    An assembly (45) includes a plurality of separate pie-shaped segments (72) forming a disk (70) around a central region (48) for retaining a plurality of tubes (46) in a concentrically spaced apart configuration. Each segment includes a support member (94) radially extending along an upstream face (96) of the segment and a plurality of annularly curved support arms (98) transversely attached to the support member and radially spaced apart from one another away from the central region for receiving respective upstream end portions of the tubes in arc-shaped spaces (100) between the arms. Each segment also includes a radial passageway (102) formed in the support member for receiving a fluid segment portion (106) and a plurality of annular passageways (104) formed in the support arms for receiving respective arm portions (108) of the fluid segment portion from the radial passageway and for conducting the respective arm portions into corresponding annular spaces (47) formed between the tubes retained by the disk.

  18. Photovoltaic solar concentrator module

    SciTech Connect

    Chiang, C.J.

    1991-05-16

    This invention consists of a planar photovoltaic concentrator module for producing an electrical signal from incident solar radiation which includes an electrically insulating housing having a front wall, an opposing back wall and a hollow interior. A solar cell having electrical terminals is positioned within the interior of the housing. A planar conductor is connected with a terminal of the solar cell of the same polarity. A lens forming the front wall of the housing is operable to direct solar radiation incident to the lens into the interior of the housing. A refractive optical element in contact with the solar cell and facing the lens receives the solar radiation directed into the interior of the housing by the lens and directs the solar radiation to the solar cell to cause the solar cell to generate an electrical signal. An electrically conductive planar member is positioned in the housing to rest on the housing back wall in supporting relation with the solar cell terminal of opposite polarity. The planar member is operable to dissipate heat radiated by the solar cell as the solar cell generates an electrical signal and further forms a solar cell conductor connected with the solar cell terminal to permit the electrical signal generated by the solar cell to be measured between the planar member and the conductor.

  19. Luminescent Solar Concentrator Daylighting

    NASA Astrophysics Data System (ADS)

    Bornstein, Jonathan G.

    1984-11-01

    Various systems that offer potential solutions to the problem of interior daylighting have been discussed in the literature. Virtually all of these systems rely on some method of tracking the sun along its azimuth and elevation, i.e., direct imaging of the solar disk. A simpler approach, however, involves a nontracking nonimaging device that effectively eliminates moving parts and accepts both the diffuse and direct components of solar radiation. Such an approach is based on a system that combines in a common luminaire the light emitted by luminescent solar concentrators (LSC), of the three primary colors, with a highly efficient artificial point source (HID metal halide) that automatically compensates for fluctuations in the LSC array via a daylight sensor and dimming ballast. A preliminary analysis suggests that this system could supply 90% of the lighting requirement, over the course of an 8 hour day, strictly from the daylight component under typical insolation con-ditions in the Southwest United States. In office buildings alone, the total aggregate energy savings may approach a half a quad annually. This indicates a very good potential for the realization of substantial savings in building electric energy consumption.

  20. Gold concentrations in abiotic materials, plants, and animals: a synoptic review

    USGS Publications Warehouse

    Eisler, R.

    2004-01-01

    Gold (Au) is ubiquitous in the environment and mined commercially at numerous locations worldwide. It is also an allergen that induces dermatitis in sensitive individuals. Gold concentrations were comparatively elevated in samples collected near gold mining and processing facilities, although no data were found for birds and non-human mammals. Maximum gold concentrations reported in abiotic materials were 0.001 ug/L in rainwater; 0.0015 ug/L in seawater near hydrothermal vents vs. <0.00004-0.0007 ug/L elsewhere; 5.0 ug/kg dry weight (DW) in the Earth's crust; 19.0 ug/L in a freshwater stream near a gold mining site; 440 ug/kg DW in atmospheric dust near a high traffic road; 843 ug/kg DW in alluvial soil near a Nevada gold mine vs. <29 ug/kg DW premining; 2.53 mg/kg DW in snow near a Russian smelter vs. <0.35 mg/kg DW at a reference site; 4.5 mg/kg DW in sewage sludge; 28.7 mg/kg DW in polymetallic sulfides from the ocean floor; and 256.0 mg/kg DW in freshwater sediments near a gold mine tailings pile vs. <5 ug/kg DW prior to mining. In plants, elevated concentrations of 19 ug Au/kg DW were reported in terrestrial vegetation near gold mining operations vs. <4 ug/kg DW at a reference site; 37 ug/kg DW in aquatic bryophytes downstream from a gold mine; 150 ug Au/kg DW in leaves of beans grown in soil containing 170 ug/kg DW; up to 1.06 mg/kg DW in algal mats of rivers receiving gold mine wastes; and 0.1-100 mg/kg DW in selected gold accumulator plants. Fish and aquatic invertebrates contained 0.1-38.0 ug Au/kg DW. In humans, gold concentrations up to 1.1 ug/L were documented in urine of dental technicians vs. 0.002-0.85 ug/L in reference populations; 2.1 ug/L in breast milk, attributed to gold dental fillings and jewelry of mothers; 1.4 mg/kg DW in hair of goldsmiths vs. a normal range of 6-880 ug/kg DW; 2.39 mg/L in whole blood of rheumatoid arthritis patients receiving gold thiol drugs to reduce inflammation (chrysotherapy) vs. a normal range of 0.2-2.0 ug/L; and 60

  1. Gold concentrations in abiotic materials, plants, and animals: a synoptic review.

    PubMed

    Eisler, R

    2004-01-01

    Gold (Au) is ubiquitous in the environment and mined commercially at numerous locations worldwide. It is also an allergen that induces dermatitis in sensitive individuals. Gold concentrations were comparatively elevated in samples collected near gold mining and processing facilities, although no data were found for birds and non-human mammals. Maximum gold concentrations reported in abiotic materials were 0.001 microg L(-1) in rainwater; 0.0015 microg L(-1) in seawater near hydrothermal vents vs. < 0.00004-0.0007 microg L(-1) elsewhere; 5.0 microg kg(-1) dry weight (DW) in the Earth's crust; 19.0 microg L(-1) in a freshwater stream near a gold mining site; 440 microg kg(-1) DW in atmospheric dust near a high traffic road; 843 microg kg(-1) DW in alluvial soil near a Nevada gold mine vs. < 29 microg kg(-1) DW premining; 2.53 mg kg(-1) DW in snow near a Russian smelter vs. < 0.35 mg kg(-1) DW at a reference site; 4.5 mg kg(-1) DW in sewage sludge; 28.7 mg kg(-1) DW in polymetallic sulfides from the ocean floor; and 256.0 mg kg(-1) DW in freshwater sediments near a gold mine tailings pile vs. < 5 microg kg(-1) DW prior to mining. In plants, elevated concentrations of 19 microg Au kg(-1) DW were reported in terrestrial vegetation near gold mining operations vs. < 4 microg kg(-1) DW at a reference site; 37 microg kg(-1) DW in aquatic bryophytes downstream from a gold mine; 150 microg Au kg(-1) DW in leaves of beans grown in soil containing 170 microg kg(-1) DW; up to 1.06 mg kg(-1) DW in algal mats of rivers receiving gold mine wastes; and 0.1-100 mg kg(-1) DW in selected gold accumulator plants. Fish and aquatic invertebrates contained 0.1-38.0 microg Au kg(-1) DW. In humans, gold concentrations up to 1.1 microg L(-1) were documented in urine of dental technicians vs. 0.002-0.85 microg L(-1) in reference populations; 2.1 microg L(-1) in breast milk, attributed to gold dental fillings and jewelry of mothers; 1.4 mg kg(-1) DW in hair of goldsmiths vs. a normal range of 6

  2. Conical electromagnetic radiation flux concentrator

    NASA Technical Reports Server (NTRS)

    Miller, E. R.

    1972-01-01

    Concentrator provides method of concentrating a beam of electromagnetic radiation into a smaller beam, presenting a higher flux density. Smaller beam may be made larger by sending radiation through the device in the reverse direction.

  3. Microsheet Glass In Solar Concentrators

    NASA Technical Reports Server (NTRS)

    Richter, Scott W.

    1993-01-01

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

  4. Concentration of Swiss Elite Orienteers.

    ERIC Educational Resources Information Center

    Seiler, Roland; Wetzel, Jorg

    1997-01-01

    A visual discrimination task was used to measure concentration among 43 members of Swiss national orienteering teams. Subjects were above average in the number of target objects dealt with and in duration of continuous concentration. For females only, ranking in orienteering performance was related to quality of concentration (ratio of correct to…

  5. High-efficiency solar concentrator

    NASA Technical Reports Server (NTRS)

    Lansing, F. L.; Dorman, J.

    1976-01-01

    A new type of solar concentrator is presented using liquid lenses and simple translational tracking mechanism. The concentrator achieves a 100:1 nominal concentration ratio and is compared in performance with a flat-plate collector having two sheets of glazing and non-selective coating. The results of the thermal analysis show that higher temperatures can be obtained with the concentrator than is possible with the non-concentrator flat-plate type. Furthermore, the thermal efficiency far exceeds that of the comparative flat-plate type for all operating conditions.

  6. High-efficiency solar concentrator

    NASA Technical Reports Server (NTRS)

    Lansing, F. L.; Dorman, J.

    1980-01-01

    A new type of solar concentrator is presented using liquid lenses and simple translational tracking mechanism. The concentrator achieves a 100:1 nominal concentration ratio and is compared in performance with a flat-plate collector having two sheets of glazing and non-selective coating. The results of the thermal analysis show that higher temperatures can be obtained with the concentrator than is possible with the non-concentrator flat-plate type. Furthermore, the thermal efficiency far exceeds that of the comparative flat-plate type for all operating conditions.

  7. Linking major and trace element headwater stream concentrations to DOC release and hydrologic conditions in a bog and peaty riparian zone

    NASA Astrophysics Data System (ADS)

    Broder, Tanja; Biester, Harald

    2017-04-01

    Peatlands and organic-rich riparian zones are known to export large amounts of dissolved organic carbon (DOC) to surface water. In organic-rich, acidic headwater streams main carriers for element export are dissolved organic matter (DOM) and organic-iron complexes. In this environment DOM might also act as major carrier for metals, which otherwise may have a low solubility. This study examines annual and short term event-based variations of major and trace elements in a headwater catchment. Patterns are used to trace hydrological pathways and element sources under different hydrologic preconditions. Furthermore, it elucidates the importance of DOC as carrier of different elements in a bog and a peaty riparian catchment. The study was conducted in a small headwater stream draining an ombrotrophic peatland with an adjacent forested area with peaty riparian soils in the Harz Mountains (Germany). Discharge sampling was conducted weekly at two sites from snowmelt to begin of snowfall and in high resolution during selected discharge events in 2013 and 2014. Element concentrations were measured by means of ICP-MS and ICP-OES. A PCA was performed for each site and for annual and event datasets. Results show that a large number of element concentrations strongly correlate with DOC concentrations at the bog site. Even elements like Ca and Mg, which are known to have a low affinity to DOC. Congruently, the first principal component integrates the DOC pattern (element loadings > 0.8: Ca, Fe, Mg, Mn, Zn, As, Sr, Cd, DOC) and explained about 35 % of total variance and even 50 % during rain events (loadings > 0.8: Al, Ca, Fe, Mg, Mn, Zn, Li, Co, As, Sr, Cd, Pb, DOC). The study cannot verify that all correlating elements bind to DOC. It is likely that also a common mobilization pattern in the upper peat layer by plant decomposition causes the same response to changes in hydrologic pathways. Additionally, a low mineral content and an enrichment of elements like Fe and Mn in the

  8. Low concentrator PV optics optimization

    NASA Astrophysics Data System (ADS)

    Sharp, Leonard; Chang, Ben

    2008-08-01

    Purpose: Cost reduction is a major focus of the solar industry. Thin film technologies and concentration systems are viable ways to reducing cost, with unique strengths and weakness for both. Most of the concentrating PV work focuses on high concentration systems for reducing energy cost. Meanwhile, many believe that low concentrators provide significant cost reduction potential while addressing the mainstream PV market with a product that acts as a flat panel replacement. This paper analyzes the relative benefit of asymmetric vs. symmetric optics for low-concentrators in light of specific PV applications. Approach: Symmetric and asymmetric concentrating PV module performance is evaluated using computer simulation to determine potential value across various geographic locations and applications. The selected optic design is modeled against standard cSi flat panels and thin film to determine application fit, system level energy density and economic value. Results: While symmetric designs may seem ideal, asymmetric designs have an advantage in energy density. Both designs are assessed for aperture, optimum concentration ratio, and ideal system array configuration. Analysis of performance across climate specific effects (diffuse, direct and circumsolar) and location specific effects (sunpath) are also presented. The energy density and energy production of low concentrators provide a compelling value proposition. More significantly, the choice of optics for a low concentrating design can affect real world performance. With the goal of maximizing energy density and return on investment, this paper presents the advantages of asymmetric optic concentration and illustrates the value of this design within specific PV applications.

  9. [Ozone concentration distribution of urban].

    PubMed

    Yin, Yong-quan; Li, Chang-mei; Ma, Gui-xia; Cui, Zhao-jie

    2004-11-01

    The increase of ozone concentration in urban is one of the most important research topics on environmental science. With the increase of nitrogen oxides and hydrogen-carbon compounds which are exhausted from cars, the ozone concentration in urban is obviously increased on sunlight, and threat of photochemistry smog will be possible. Therefore, it is very important to monitor and study the ozone concentration distribution in urban. The frequency-distribution, diurnal variation and monthly variation of ozone concentration were studied on the campus of Shandong University during six months monitoring. The influence of solar radiation and weather conditions on ozone concentration were discussed. The frequency of ozone concentration less than 200 microg/m3 is 96.88%. The ozone concentration has an obvious diurnal variation. The ozone concentration in the afternoon is higher than in the morning and in the evening. The maximum appears in June, when it is the strong solar radiation and high air-temperature. The weather conditions also influence the ozone concentration. The ozone concentration in clear day is higher than in rainy and cloudy day.

  10. Bruise chromophore concentrations over time

    NASA Astrophysics Data System (ADS)

    Duckworth, Mark G.; Caspall, Jayme J.; Mappus, Rudolph L., IV; Kong, Linghua; Yi, Dingrong; Sprigle, Stephen H.

    2008-03-01

    During investigations of potential child and elder abuse, clinicians and forensic practitioners are often asked to offer opinions about the age of a bruise. A commonality between existing methods of bruise aging is analysis of bruise color or estimation of chromophore concentration. Relative chromophore concentration is an underlying factor that determines bruise color. We investigate a method of chromophore concentration estimation that can be employed in a handheld imaging spectrometer with a small number of wavelengths. The method, based on absorbance properties defined by Beer-Lambert's law, allows estimation of differential chromophore concentration between bruised and normal skin. Absorption coefficient data for each chromophore are required to make the estimation. Two different sources of this data are used in the analysis- generated using Independent Component Analysis and taken from published values. Differential concentration values over time, generated using both sources, show correlation to published models of bruise color change over time and total chromophore concentration over time.

  11. Optical assessment of nonimaging concentrators.

    PubMed

    Timinger, A; Kribus, A; Ries, H; Smith, T; Walther, M

    2000-11-01

    An optical measurement method for nonimaging radiation concentrators is proposed. A Lambertian light source is placed in the exit aperture of the concentrator. Looking into the concentrator's entrance aperture from a remote position, one can photograph the transmission patterns. The patterns show the transmission of radiation through the concentrator with the full resolution of the four-dimensional phase space of geometric optics. By matching ray-tracing simulations to the measurement, one can achieve detailed and accurate information about the geometry of the concentrator. This is a remote, noncontact measurement and can be performed in situ for installed concentrators. Additional information regarding small-scale reflector waviness and surface reflectivity can also be obtained from the same measurement with additional analysis.

  12. Fluctuating Concentrations in Atmospheric Dispersion

    NASA Astrophysics Data System (ADS)

    Devaull, George Ellis, III

    This thesis presents theoretical models and experimental results of average and instantaneous concentration measurements from a series of atmospheric dispersion experiments conducted under both unstable and stable meteorological conditions. The experiments were undertaken at two different sites, over both flat and gently rolling terrain. Two types of surface -level point aerosol sources were used. One is a fog-oil smoke and the other is a hexachloroethane chemical smoke. Measurements of concentration at points along crosswind transects were taken over time periods of an hour at distances to several kilometers from the source. These measurements included both aerosol photometer records of the instantaneous concentration taken at a 1 Hz sampling rate and aspirated filters for mean concentration measurements. The flat terrain site was located at Camp Atterbury, Indiana, while the gently rolling terrain site was near Red Bluff, California. Meteorological measurements at these sites included both tower measurements and upper -air balloon soundings. These measurements were used in determining the atmospheric boundary layer scaling parameters in the unstable tests and in characterizing the complex wind field for the stable tests. The data compare favorably with developed models for both the mean and variance in concentration. Concentration fluctuation intensity ranges from 2 near the plume centerline to greater than 20 at the plume edge. Intermittency is important at all locations, with positive concentrations recorded on the mean plume centerline only 20% to 50% of the time. Point concentration histograms are shown to agree with the exponential distribution for concentrations greater than zero. Spectra of the concentration data show an inertial -convective subrange with a -5/3 power law versus frequency behavior. Integral time scales of the concentration records at all individual sampling points are approximately constant within a test and are equal to the mean duration

  13. Utility-scale photovoltaic concentrators

    SciTech Connect

    None, None

    2009-01-18

    The photovoltaics concentrators section of the Renewable Energy Technology Characterizations describes the technical and economic status of this emerging renewable energy option for electricity supply.

  14. Continuous flow dielectrophoretic particle concentrator

    SciTech Connect

    Cummings, Eric B.

    2007-04-17

    A continuous-flow filter/concentrator for separating and/or concentrating particles in a fluid is disclosed. The filter is a three-port device an inlet port, an filter port and a concentrate port. The filter separates particles into two streams by the ratio of their dielectrophoretic mobility to their electrokinetic, advective, or diffusive mobility if the dominant transport mechanism is electrokinesis, advection, or diffusion, respectively.Also disclosed is a device for separating and/or concentrating particles by dielectrophoretic trapping of the particles.

  15. Mixing of atmospheric gas concentrations.

    PubMed

    Clement, C F; Ford, I J; Twohy, C H

    2000-04-24

    Atmospheric gas concentrations were measured at 1 s intervals in the upper troposphere during a flight through and near the anvil of a storm. The observed very high correlations between the concentrations of CO and CH4 are interpreted as arising from the mixing of two distinct air masses with differing concentrations of each species, and is due to the nearly identical diffusivities of CO and CH4 in air. We find that the correlations depend on the period over which each concentration measurement was made. Correlations in measurements made over short periods decay with time, while correlations over larger scales remain high. We interpret this using a simple mixing model.

  16. Fructosamine concentrations in hyperglycemic cats.

    PubMed Central

    Lutz, T A; Rand, J S; Ryan, E

    1995-01-01

    The aims of this study were 1) to establish a reference range for fructosamine in cats using a commercial fructosamine kit; 2) to demonstrate that the fructosamine concentration is not increased by transient hyperglycemia of 90 min duration, simulating hyperglycemia of acute stress; and 3) to determine what percentage of blood samples submitted to a commercial laboratory from 95 sick cats had evidence of persistent hyperglycemia based on an elevated fructosamine concentration. Reference intervals for the serum fructosamine concentration were established in healthy, normoglycemic cats using a second generation kit designed for the measurement of the fructosamine concentration in humans. Transient hyperglycemia of 90 min duration was induced by IV glucose injection in healthy cats. Multisourced blood samples that were submitted to a commercial veterinary laboratory either as fluoride oxalated plasma or serum were used to determine the percentage of hyperglycemic cats having persistent hyperglycemia. The reference interval for the serum fructosamine concentration was 249 to 406 mumol/L. Transient hyperglycemia of 90 min duration did not increase the fructosamine concentration and there was no correlation between fructosamine and blood glucose. In contrast, the fructosamine concentration was correlated with the glucose concentration in sick hyper- and normoglycemic cats. It is concluded that the fructosamine concentration is a useful marker for the detection of persistent hyperglycemia and its differentiation from transient stress hyperglycemia. Fructosamine determinations should be considered when blood glucose is 12 to 20 mmol/L and only a single blood sample is available for analysis. PMID:7757920

  17. Plasma Efavirenz Concentrations Are Associated With Lipid and Glucose Concentrations

    PubMed Central

    Sinxadi, Phumla Zuleika; McIlleron, Helen Margaret; Dave, Joel Alex; Smith, Peter John; Levitt, Naomi Sharlene; Haas, David William; Maartens, Gary

    2016-01-01

    Abstract Efavirenz-based antiretroviral therapy (ART) has been associated with dyslipidemia and dysglycemia, risk factors for cardiovascular disease. However, the pathogenesis is not well understood. We characterized relationships between plasma efavirenz concentrations and lipid and glucose concentrations in HIV-infected South Africans. Participants on efavirenz-based ART were enrolled into a cross-sectional study. The oral glucose tolerance test was performed after an overnight fast, and plasma drawn for mid-dosing interval efavirenz, fasting total cholesterol, low-density lipoprotein (LDL) and high-density lipoprotein (HDL) cholesterol, and triglycerides concentrations. Among 106 participants (77 women), median age was 38 years, median CD4 + T-cell count was 322 cells/μL, median duration on ART was 18 months, and median (interquartile range) efavirenz concentration was 2.23 (1.66 to 4.10) μg/mL. On multivariable analyses (adjusting for age, sex, body mass index, and ART duration) doubling of efavirenz concentrations resulted in mean changes in mmol/L (95%CI) of: total cholesterol (0.40 [0.22 to 0.59]), LDL cholesterol (0.19 [0.04 to 0.30]), HDL cholesterol (0.14 [0.07 to 0.20]), triglycerides (0.17 [0.03 to 0.33]), fasting glucose (0.18 [0.03 to 0.33]), and 2-h glucose concentrations (0.33 [0.08 to 0.60]). Among 57 participants with CYP2B6 genotype data, associations between slow metabolizer genotypes and metabolic profiles were generally consistent with those for measured efavirenz concentrations. Higher plasma efavirenz concentrations are associated with higher plasma lipid and glucose concentrations. This may have implications for long-term cardiovascular complications of efavirenz-based ART, particularly among populations with high prevalence of CYP2B6 slow metabolizer genotypes. PMID:26765416

  18. Advanced solar concentrator: Executive summary

    NASA Technical Reports Server (NTRS)

    1981-01-01

    The preliminary design of a point-focusing solar concentrator, consisting of a steerable space frame structure supporting a paraboloidal mirror glass reflector, is described. A mass production, operation, and maintenance cost assessment is presented. A conceptual evaluation of a modified concentrator design is included. The detailed design of one of the lightweight, structurally efficient reflective elements comprising the paraboloidal reflective surface is given.

  19. Optimal concentrations in transport systems.

    PubMed

    Jensen, Kaare H; Kim, Wonjung; Holbrook, N Michele; Bush, John W M

    2013-06-06

    Many biological and man-made systems rely on transport systems for the distribution of material, for example matter and energy. Material transfer in these systems is determined by the flow rate and the concentration of material. While the most concentrated solutions offer the greatest potential in terms of material transfer, impedance typically increases with concentration, thus making them the most difficult to transport. We develop a general framework for describing systems for which impedance increases with concentration, and consider material flow in four different natural systems: blood flow in vertebrates, sugar transport in vascular plants and two modes of nectar drinking in birds and insects. The model provides a simple method for determining the optimum concentration copt in these systems. The model further suggests that the impedance at the optimum concentration μopt may be expressed in terms of the impedance of the pure (c = 0) carrier medium μ0 as μopt 2(α)μ0, where the power α is prescribed by the specific flow constraints, for example constant pressure for blood flow (α = 1) or constant work rate for certain nectar-drinking insects (α = 6). Comparing the model predictions with experimental data from more than 100 animal and plant species, we find that the simple model rationalizes the observed concentrations and impedances. The model provides a universal framework for studying flows impeded by concentration, and yields insight into optimization in engineered systems, such as traffic flow.

  20. Process for concentrated biomass saccharification

    DOEpatents

    Hennessey, Susan M.; Seapan, Mayis; Elander, Richard T.; Tucker, Melvin P.

    2010-10-05

    Processes for saccharification of pretreated biomass to obtain high concentrations of fermentable sugars are provided. Specifically, a process was developed that uses a fed batch approach with particle size reduction to provide a high dry weight of biomass content enzymatic saccharification reaction, which produces a high sugars concentration hydrolysate, using a low cost reactor system.

  1. Program for Paraboloidal Solar Concentrators

    NASA Technical Reports Server (NTRS)

    Wen, Liang-Chi; O'Brien, Philip

    1987-01-01

    Solar-Concentrator Code for Paraboloidal Dishes (SOLCOL) aids in design and analysis of solar collectors in space station. Calculates quality of solar image and flux distribution on specified target surface. Receiver target is focal plane cylinder, hemisphere, or any arbitrary surface, normals to which supplied. Used to assess optical performance of concentrator. Written in FORTRAN 77.

  2. Rational Normalization of Concentration Measures.

    ERIC Educational Resources Information Center

    Bonckaert, P.; Egghe, L.

    1991-01-01

    Discusses normalization features of good concentration measures and extends the range of values of concentration measures that are population-size-independent. Rational normalization is described, and mathematical formulas for the coefficient of variation, Pratt's measure, the Gini index, Theil's measure, and Atkinson's indices are explained. (14…

  3. Monolithic microfluidic concentrators and mixers

    DOEpatents

    Frechet, Jean M.; Svec, Frantisek; Yu, Cong; Rohr, Thomas

    2005-05-03

    Microfluidic devices comprising porous monolithic polymer for concentration, extraction or mixing of fluids. A method for in situ preparation of monolithic polymers by in situ initiated polymerization of polymer precursors within microchannels of a microfluidic device and their use for solid phase extraction (SPE), preconcentration, concentration and mixing.

  4. MODELING INDOOR CONCENTRATIONS AND EXPOSURE

    EPA Science Inventory

    The paper discusses the use of an indoor air quality model, EXPOSURE, to predict pollutant concentrations and exposures. The effects of indoor air pollutants depend on the concentrations of the pollutants and the exposure of individuals to the pollutants. The air pollutant concen...

  5. Optimal concentrations in transport systems

    PubMed Central

    Jensen, Kaare H.; Kim, Wonjung; Holbrook, N. Michele; Bush, John W. M.

    2013-01-01

    Many biological and man-made systems rely on transport systems for the distribution of material, for example matter and energy. Material transfer in these systems is determined by the flow rate and the concentration of material. While the most concentrated solutions offer the greatest potential in terms of material transfer, impedance typically increases with concentration, thus making them the most difficult to transport. We develop a general framework for describing systems for which impedance increases with concentration, and consider material flow in four different natural systems: blood flow in vertebrates, sugar transport in vascular plants and two modes of nectar drinking in birds and insects. The model provides a simple method for determining the optimum concentration copt in these systems. The model further suggests that the impedance at the optimum concentration μopt may be expressed in terms of the impedance of the pure (c = 0) carrier medium μ0 as μopt∼2αμ0, where the power α is prescribed by the specific flow constraints, for example constant pressure for blood flow (α = 1) or constant work rate for certain nectar-drinking insects (α = 6). Comparing the model predictions with experimental data from more than 100 animal and plant species, we find that the simple model rationalizes the observed concentrations and impedances. The model provides a universal framework for studying flows impeded by concentration, and yields insight into optimization in engineered systems, such as traffic flow. PMID:23594815

  6. Inflatable Solar Thermal Concentrator Delivered

    NASA Technical Reports Server (NTRS)

    Tolbert, Carol M.

    1999-01-01

    Space-based solar thermal power systems are very appealing as a space power source because they generate power efficiently. However, solar thermal (dynamic) systems currently incorporate rigid concentrators that are relatively heavy and require significant packaging volume and robust deployment schemes. In many ways, these requirements make these systems less appealing than photovoltaic systems. As an alternative to solar thermal power systems with rigid concentrators, solar thermal power systems with thin film inflation-deployed concentrators have low cost, are lightweight, and are efficiently packaged and deployed. Not only are inflatable concentrators suitable for low Earth orbit and geosynchronous orbit applications, but they can be utilized in deep space missions to concentrate solar energy to high-efficiency solar cells.

  7. A novel way to monitor urine concentration: fluorescent concentration matrices.

    PubMed

    Dubayova, Katarina; Luckova, Iveta; Sabo, Jan; Karabinos, Anton

    2015-01-01

    The amount of water found in urine is important diagnostic information; nevertheless it is not yet directly determined. Indirectly, the water content in urine is expressed by its density (specific gravity). However, without the diuresis value it is not possible to determine whether the increase in density of urine is due to a decrease in water secretion or an increase in the concentration of secreted substances. This problem can be solved by the use of fluorescent concentration 3D-matrices which characterise urine concentration through the pφ (or -logφ) value of the first fluorescence centre. The urine fluorescent concentration 3D-matrix was created by the alignment of the synchronous spectra of the dilution series of urine starting from undiluted (pφ = 0) to 1000-fold diluted urine (pφ = 3). Using the fluorescence concentration 3D-matrix analysis of the urine samples from healthy individuals, a reference range was established for the value pφ, determining the normal, concentrated or diluted type of urine. The diagnostic potential of this approach was tested on urine samples from two patients with a chronic glomerulonephritis. The pφ value of the urine fluorescence concentration 3D-matrix analysis determines whether the urine sample falls within the normal, concentrated or diluted type of urine. This parameter can be directly utilised in sportsmen's hydration state monitoring, as well as in the diagnosis and treatment of serious diseases. An important advantage of this novel diagnostic approach is that a 12/24 h urine collection is not required, which predetermines it for use especially within paediatrics.

  8. A Novel Way to Monitor Urine Concentration: Fluorescent Concentration Matrices

    PubMed Central

    Luckova, Iveta; Sabo, Jan; Karabinos, Anton

    2015-01-01

    Background: The amount of water found in urine is important diagnostic information; nevertheless it is not yet directly determined. Indirectly, the water content in urine is expressed by its density (specific gravity). However, without the diuresis value it is not possible to determine whether the increase in density of urine is due to a decrease in water secretion or an increase in the concentration of secreted substances. This problem can be solved by the use of fluorescent concentration 3D-matrices which characterise urine concentration through the pφ (or -logφ) value of the first fluorescence centre. Materials and Methods: The urine fluorescent concentration 3D-matrix was created by the alignment of the synchronous spectra of the dilution series of urine starting from undiluted (pφ = 0) to 1000-fold diluted urine (pφ = 3). Results: Using the fluorescence concentration 3D-matrix analysis of the urine samples from healthy individuals, a reference range was established for the value pφ, determining the normal, concentrated or diluted type of urine. The diagnostic potential of this approach was tested on urine samples from two patients with a chronic glomerulonephritis. Conclusion: The pφ value of the urine fluorescence concentration 3D-matrix analysis determines whether the urine sample falls within the normal, concentrated or diluted type of urine. This parameter can be directly utilised in sportsmen’s hydration state monitoring, as well as in the diagnosis and treatment of serious diseases. An important advantage of this novel diagnostic approach is that a 12/24 h urine collection is not required, which predetermines it for use especially within paediatrics. PMID:25737974

  9. Concentrating membrane proteins using ultrafiltration without concentrating detergents.

    PubMed

    Feroz, Hasin; Vandervelden, Craig; Ikwuagwu, Bon; Ferlez, Bryan; Baker, Carol S; Lugar, Daniel J; Grzelakowski, Mariusz; Golbeck, John H; Zydney, Andrew L; Kumar, Manish

    2016-10-01

    Membrane proteins (MPs) are of rapidly growing interest in the design of pharmaceutical products, novel sensors, and synthetic membranes. Ultrafiltration (UF) using commercially available centrifugal concentrators is typically employed for laboratory-scale concentration of low-yield MPs, but its use is accompanied by a concomitant increase in concentration of detergent micelles. We present a detailed analysis of the hydrodynamic processes that control detergent passage during ultrafiltration of MPs and propose methods to optimize detergent passage during protein concentration in larger-scale membrane processes. Experiments were conducted using nonionic detergents, octyl-β-D glucoside (OG), and decyl-β-D maltoside (DM) with the bacterial water channel protein, Aquaporin Z (AqpZ) and the light driven chloride pump, halorhodopsin (HR), respectively. The observed sieving coefficient (So ), a measure of detergent passage, was evaluated in both stirred cell and centrifugal systems. So for DM and OG increased with increasing filtrate flux and decreasing shear rates in the stirred cell, that is, with increasing concentration polarization (CP). Similar effects were observed during filtration of MP-detergent (MPD) micelles. However, lower transmission was observed in the centrifugal system for both detergent and MPD systems. This is attributed to free convection-induced shear and hence reduced CP along the membrane surface during centrifugal UF. Thus to concentrate MPs without retention of detergent, design of UF systems that promote CP is required. Biotechnol. Bioeng. 2016;113: 2122-2130. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  10. Solar Concentrator Advanced Development Program

    NASA Technical Reports Server (NTRS)

    Knasel, Don; Ehresman, Derik

    1989-01-01

    The Solar Concentrator Advanced Development Project has successfully designed, fabricated, and tested a full scale prototypical solar dynamic concentrator for space station applications. A Truss Hexagonal Panel reflector was selected as a viable solar concentrator concept to be used for space station applications. This concentrator utilizes a modular design approach and is flexible in attainable flux profiles and assembly techniques. The detailed design of the concentrator, which included structural, thermal and optical analysis, identified the feasibility of the design and specific technologies that were required to fabricate it. The needed surface accuracy of the reflectors surface was found to be very tight, within 5 mrad RMS slope error, and results in very close tolerances for fabrication. To meet the design requirements, a modular structure composed of hexagonal panels was used. The panels, made up of graphite epoxy box beams provided the strength, stiffness and dimensional stability needed. All initial project requirements were met or exceeded by hardware demonstration. Initial testing of structural repeatability of a seven panel portion of the concentrator was followed by assembly and testing of the full nineteen panel structure. The testing, which consisted of theodolite and optical measurements over an assembly-disassembly-reassembly cycle, demonstrated that the concentrator maintained the as-built contour and optical characteristics. The facet development effort within the project, which included developing the vapor deposited reflective facet, produced a viable design with demonstrated optical characteristics that are within the project goals.

  11. Altering prolactin concentrations in sows.

    PubMed

    Farmer, C

    2016-07-01

    Prolactin has a multiplicity of actions, but it is of particular importance in gestating and lactating animals. In sows, it is involved in the control of mammary development and also holds essential roles in the lactogenic and galactopoietic processes. Furthermore, low circulating concentrations of prolactin are associated with the agalactia syndrome. The crucial role of prolactin makes it important to understand the various factors that can alter its secretion. Regulation of prolactin secretion is largely under the negative control of dopamine, and dopamine agonists consistently decrease prolactin concentrations in sows. On the other hand, injections of dopamine antagonists can enhance circulating prolactin concentrations. Besides pharmacologic agents, many other factors can also alter prolactin concentrations in sows. The use of Chinese-derived breeds, for instance, leads to increased prolactin concentrations in lactating sows compared with standard European white breeds. Numerous husbandry and feeding practices also have a potential impact on prolactin concentrations in sows. Factors, such as provision of nest-building material prepartum, housing at farrowing, high ambient temperature, stress, transient weaning, exogenous thyrotropin-releasing factor, exogenous growth hormone-releasing factor, nursing frequency, prolonged photoperiod, fasting, increased protein and/or energy intake, altered energy sources, feeding high-fiber diets, sorghum ergot or plant extracts, were all studied with respect to their prolactinemic properties. Although some of these practices do indeed affect circulating prolactin concentrations, none leads to changes as drastic as those brought about by dopamine agonists or antagonists. It appears that the numerous factors regulating prolactin concentrations in sows are still not fully elucidated, and that studies to develop novel applicable ways of increasing prolactin concentrations in sows are warranted.

  12. Tank waste concentration mechanism study

    SciTech Connect

    Pan, L.C.; Johnson, L.J.

    1994-09-01

    This study determines whether the existing 242-A Evaporator should continue to be used to concentrate the Hanford Site radioactive liquid tank wastes or be replaced by an alternative waste concentration process. Using the same philosophy, the study also determines what the waste concentration mechanism should be for the future TWRS program. Excess water from liquid DST waste should be removed to reduce the volume of waste feed for pretreatment, immobilization, and to free up storage capacity in existing tanks to support interim stabilization of SSTS, terminal cleanout of excess facilities, and other site remediation activities.

  13. Thermodynamic efficiency of solar concentrators.

    PubMed

    Shatz, Narkis; Bortz, John; Winston, Roland

    2010-04-26

    The optical thermodynamic efficiency is a comprehensive metric that takes into account all loss mechanisms associated with transferring flux from the source to the target phase space, which may include losses due to inadequate design, non-ideal materials, fabrication errors, and less than maximal concentration. We discuss consequences of Fermat's principle of geometrical optics and review étendue dilution and optical loss mechanisms associated with nonimaging concentrators. We develop an expression for the optical thermodynamic efficiency which combines the first and second laws of thermodynamics. As such, this metric is a gold standard for evaluating the performance of nonimaging concentrators. We provide examples illustrating the use of this new metric for concentrating photovoltaic systems for solar power applications, and in particular show how skewness mismatch limits the attainable optical thermodynamic efficiency.

  14. Concentrating Solar Power (Fact Sheet)

    SciTech Connect

    DOE Solar Energy Technologies Program

    2011-10-13

    Concentrating Solar Power (CSP) offers a utility-scale, firm, dispatchable renewable energy option that can help meet the nation's goal of making solar energy cost competitive with other energy sources by the end of the decade.

  15. Silicon concentrator solar cell development

    NASA Astrophysics Data System (ADS)

    Green, Martin A.; Jianhua, Zhao; Aihua, Wang; Blakers, A. W.

    1990-05-01

    This project involved the development and supply of 550 silicon concentrator solar cells for use in prototype point-focus concentrator modules. The cells were to have a designed illumination area of 12.5 by 12.5 mm and to be designed for use with prismatic covers at a geometric concentration ratio of 200X. The target efficiency of 24 percent was comfortably exceeded, with efficiencies as high as 25.2 percent reached in the designed concentration ratio range. A combined lens/cell efficiency of 24.4 percent was measured at Sandia using a cell supplied during this project and a point focus Fresnel lens. Subsequently, a peak module efficiency of 20.3 percent was achieved at Sandia using 12 cells and lenses. This is believed to be the first photovoltaic module to surpass the 20 percent efficiency milestone.

  16. Luminescent solar concentrators: Semiconductor solution

    NASA Astrophysics Data System (ADS)

    Debije, Michael

    2017-03-01

    Reabsorption losses have long been holding back the commercial viability of luminescent solar concentrators. Now, non-toxic silicon-based quantum dots with enhanced Stokes shift may enable the technology to enjoy practical implementation.

  17. Meteorite concentration mechanisms in Antarctica

    NASA Technical Reports Server (NTRS)

    Annexstad, J. O.

    1986-01-01

    The location of most Antarctic meteorite finds is on stagnant, highly ablative surfaces known as blue ice. The role of blue ice as transporter, concentrator, and preserver of specimens from the time of fall until find is discussed.

  18. Optimal concentrations in nectar feeding

    PubMed Central

    Kim, Wonjung; Gilet, Tristan; Bush, John W. M.

    2011-01-01

    Nectar drinkers must feed quickly and efficiently due to the threat of predation. While the sweetest nectar offers the greatest energetic rewards, the sharp increase of viscosity with sugar concentration makes it the most difficult to transport. We here demonstrate that the sugar concentration that optimizes energy transport depends exclusively on the drinking technique employed. We identify three nectar drinking techniques: active suction, capillary suction, and viscous dipping. For each, we deduce the dependence of the volume intake rate on the nectar viscosity and thus infer an optimal sugar concentration consistent with laboratory measurements. Our results provide the first rationale for why suction feeders typically pollinate flowers with lower sugar concentration nectar than their counterparts that use viscous dipping. PMID:21949358

  19. Mitragynine concentrations in two fatalities.

    PubMed

    Domingo, Olwen; Roider, Gabriele; Stöver, Andreas; Graw, Matthias; Musshoff, Frank; Sachs, Hans; Bicker, Wolfgang

    2017-02-01

    Two cases of fatalities are reported of which the recreational use of Mitragyna speciosa ("kratom") could be confirmed. One of these cases presents with one of the highest postmortem mitragynine concentrations published to date. Our results show that even extremely high mitragynine blood concentrations following the consumption of kratom do not necessarily have to be the direct cause of death in such fatalities as a result of an acute overdose. The two cases are compared with regard to the differences in mitragynine concentrations detected and the role of mitragynine in the death of the subjects. Irrespective of the big differences in mitragynine concentrations in the postmortem blood samples, mitragynine was not the primary cause of death in either of the two cases reported here. Additionally, by rough estimation, a significant difference in ratio of mitragynine to its diastereomers in the blood and urine samples between the two cases could be seen.

  20. Thin film concentrator panel development

    NASA Technical Reports Server (NTRS)

    Zimmerman, D. K.

    1982-01-01

    The development and testing of a rigid panel concept that utilizes a thin film reflective surface for application to a low-cost point-focusing solar concentrator is discussed. It is shown that a thin film reflective surface is acceptable for use on solar concentrators, including 1500 F applications. Additionally, it is shown that a formed steel sheet substrate is a good choice for concentrator panels. The panel has good optical properties, acceptable forming tolerances, environmentally resistant substrate and stiffeners, and adaptability to low to mass production rates. Computer simulations of the concentrator optics were run using the selected reflector panel design. Experimentally determined values for reflector surface specularity and reflectivity along with dimensional data were used in the analysis. The simulations provided intercept factor and net energy into the aperture as a function of aperture size for different surface errors and pointing errors. Point source and Sun source optical tests were also performed.

  1. Assessment of renal concentrating ability.

    PubMed Central

    Curtis, J R; Donovan, B A

    1979-01-01

    Maximum urine osmolality was measured during a 24-hour control period in normal ambulant and working subjects and hospital inpatients and compared with that achieved after intramuscular injection of 4 microgram desamino-cys-1-8-D-arginine vasopressin (DDAVP). Most of the normal subjects passed maximally concentrated urine at some time during the control period. The results suggest that in less active subjects or hospital inpatients the DDAVP test is a suitable method of assessing renal concentrating ability. PMID:421089

  2. Teorell instability in concentration polarization

    NASA Astrophysics Data System (ADS)

    Abu-Rjal, Ramadan; Prigozhin, Leonid; Rubinstein, Isaak; Zaltzman, Boris

    2015-08-01

    We investigate the development of electro-osmotic (Teorell) oscillations at a weakly charged microporous membrane without a preimposed transmembrane electrolyte concentration drop. This drop, necessary for the occurrence of oscillations, develops spontaneously as a result of concentration polarization in the solution layers adjacent to the membrane. A three-layer model comprising a membrane flanked by two diffusion layers is proposed and analyzed for galvano- and potentiostatic regimes of operation.

  3. Neuroleptic bioequivalency: tablet versus concentrate.

    PubMed

    Fann, W E; Moreira, A F

    1985-01-01

    Two forms of the antipsychotic neuroleptic molindone were administered to newly admitted psychotic patients. A coated tablet was administered for ten days, followed by administration of liquid concentrate in equivalent doses for four days. Plasma was analyzed by gas chromatography with electron capture for the parent compound following each dosing phase. Our data suggest that oral doses of the tablet and concentrate forms of this neuroleptic are equivalent in clinical bioavailability.

  4. Manganese concentrations in Scottish groundwater.

    PubMed

    Homoncik, Sally C; Macdonald, Alan M; Heal, Kate V; Dochartaigh, Brighid E O; Ngwenya, Bryne T

    2010-05-15

    Groundwater is increasingly being used for public and private water supplies in Scotland, but there is growing evidence that manganese (Mn) concentrations in many groundwater supplies exceed the national drinking water limit of 0.05 mg l(-1). This study examines the extent and magnitude of high Mn concentrations in groundwater in Scotland and investigates the factors controlling Mn concentrations. A dataset containing 475 high quality groundwater samples was compiled using new data from Baseline Scotland supplemented with additional high quality data where available. Concentrations ranged up to 1.9 mg l(-1); median Mn concentration was 0.013 mg l(-1) with 25th and 75th percentiles 0.0014 and 0.072 mg l(-1) respectively. The Scottish drinking water limit (0.05 mg l(-1)) was exceeded for 30% of samples and the WHO health guideline (0.4 mg l(-1)) by 9%; concentrations were highest in the Carboniferous sedimentary aquifer in central Scotland, the Devonian sedimentary aquifer of Morayshire, and superficial aquifers. Further analysis using 137 samples from the Devonian aquifers indicated strong redox and pH controls (pH, Eh and dissolved oxygen accounted for 58% of variance in Mn concentrations). In addition, an independent relationship between Fe and Mn was observed, suggesting that Fe behaviour in groundwater may affect Mn solubility. Given the redox status and pH of Scottish groundwaters the most likely explanation is sorption of Mn to Fe oxides, which are released into solution when Fe is reduced. Since the occurrence of elevated Mn concentrations is widespread in groundwaters from all aquifer types, consideration should be given to monitoring Mn more widely in both public and private groundwater supplies in Scotland and by implication elsewhere. Copyright 2010 NERC. Published by Elsevier B.V. All rights reserved.

  5. Postmortem distribution of trazodone concentrations.

    PubMed

    McIntyre, Iain M; Mallett, Phyllis; Stabley, Robert

    2015-06-01

    Non-toxic postmortem trazodone tissue (liver) concentrations have not been previously described. Liver trazodone concentrations were compared to peripheral blood and central blood concentrations in 19 medical examiner cases. Postmortem blood specimens were initially screened for alcohol and simple volatiles, drugs of abuse, and alkaline drugs. Trazodone, when detected by the alkaline drug screen, was subsequently confirmed and quantified by a high performance liquid chromatography procedure. Re-analyses showed that there may be degradation of trazodone in postmortem blood stored at 4°C. There was, on average, about a 20% decrease in samples stored up to eight months. These data suggest that postmortem trazodone peripheral blood concentrations may be considered non-toxic to at least 1.0mg/L with liver concentrations to at least 2.2mg/kg. Overall, trazodone concentrations ranged from 0.08-6.1mg/L in peripheral blood, 0.07-7.1mg/L in central blood, and 0.39-26mg/kg in liver. The median trazodone central blood to peripheral blood ratio was 0.98 (N=19). The liver to peripheral blood ratios showed a median value of 2.8L/kg (N=18). Given that a liver to peripheral blood ratio less than 5L/kg is consistent with little to no propensity for postmortem redistribution, these data demonstrate that trazodone is unlikely to show significant redistribution.

  6. Design and development of a high-concentration photovoltaic concentrator

    SciTech Connect

    Hodge, R C

    1982-04-01

    The design and development of a high concentration photovoltaic concentrator module is discussed. The design concept described herein incorporates a curved groove domed Fresnel lens, a high concentration etched multiple vertical junction (EMVJ) solar cell and a passively cooled direct-bonded copper cell mount all packaged in a plastic module. Two seven inch diameter 1200x domed Fresnel lenses were fabricated using single point diamond turning technology. Testing at both GE and Sandia confirmed optical transmission efficiencies of over 83%. Samples of the latest available EMVJ cells were mounted and installed, with a domed Fresnel lens, into a prototype module. Subsequent testing demonstrated net lens-cell efficiencies of 10 to 13%. As a result of this program, salient conclusions have been formulated as to this technology.

  7. Geologic sources and concentrations of selenium in the West-Central Denver Basin, including the Toll Gate Creek watershed, Aurora, Colorado, 2003-2007

    USGS Publications Warehouse

    Paschke, Suzanne S.; Walton-Day, Katherine; Beck, Jennifer A.; Webbers, Ank; Dupree, Jean A.

    2014-01-01

    concentrations were greatest in samples containing indications of reducing conditions and organic matter (dark gray to black claystones and lignite horizons). The Toll Gate Creek watershed is situated in a unique hydrogeologic setting in the west-central part of the Denver Basin such that weathering of Cretaceous- to Tertiary-aged, non-marine, selenium-bearing rocks releases selenium to groundwater and surface water under present-day semi-arid environmental conditions. The Denver Formation contains several known and suspected geologic sources of selenium including: (1) lignite deposits; (2) tonstein partings; (3) organic-rich bentonite claystones; (4) salts formed as secondary weathering products; and possibly (5) the Cretaceous-Tertiary boundary. Organically complexed selenium and/or selenium-bearing pyrite in the enclosing claystones are likely the primary mineral sources of selenium in the Denver Formation, and correlations between concentration of dissolved selenium and dissolved organic carbon in groundwater indicate weathering and dissolution of organically complexed selenium from organic-rich claystone is a primary process mobilizing selenium. Secondary salts accumulated along fractures and bedding planes in the weathered zone are another potential geologic source of selenium, although their composition was not specifically addressed by the solids analyses. Results from this and previous work indicate that shallow groundwater and streams similarly positioned over Denver Formation claystone units at other locations in the Denver Basin also may contain concentrations of dissolved selenium greater than the Colorado aquatic-life standard or the drinking- water standard.

  8. Concentrating Engines and the Kidney

    PubMed Central

    Stephenson, John L.

    1973-01-01

    Mass balance relations, valid for any counterflow system, are derived and applied to a central core model of the renal medulla, in which descending Henle's limbs (DHL), ascending Henle's limbs (AHL), and collecting ducts (CD) exchange with a central vascular core (VC) formed by vasa recta loops, assumed so highly permeable that the core functions as a single tube open at the cortical end, closed at the papillary. Solute supplied to the VC primarily by the water impermeable AHL may either enter the DHL to be recycled or remain in the core to extract water by osmosis from DHL and CD. If concentrations in core and descending flows are nearly equal, then for all degrees of recycling the ratio of entering DHL concentration to loop concentration is given by r = 1/[1 - fT(1 - fU)], where fT is the fractional net solute transport out of AHL and fU is the ratio of CD flow to the sum of CD and AHL flows. Differential equations for a single solute are derived for core and AHL concentrations. Explicit analytic solutions are given for solute transport out of the AHL governed by Michaelis-Menten kinetics. Finally the energy requirements for concentration are analyzed. PMID:4714446

  9. Unusually high indoor radon concentrations

    NASA Astrophysics Data System (ADS)

    Ennemoser, O.; Ambach, W.; Brunner, P.; Schneider, P.; Oberaigner, W.; Purtscheller, F.; Stingl, V.

    Measurements of indoor radon concentrations in the village Umhausen (2600 inhabitants, Ötztal valley, Tyrol, Austria) revealed unusually high indoor radon concentrations up to 274,000 Bq m -3. The medians measured on the basements were 3750 Bq m -3 in winter and 361 Bq m -3 in summer, those on the ground floors were 1180 Bq m -3 and 210 Bq m -3, respectively. Seventy-one per cent of the houses showed basement radon concentrations above the Austrian action level of 400 Bq m -3 in winter, 33% in summer. There are indications that the high radon concentrations are due to a giant rock slide about 8700 years ago. The unusually high radon concentrations in Umhausen coincide with a statistically significant increase in lung cancer mortality. For the period 1970-1991 the age and sex standardized mortality rate is 3.85 (95% confidence interval: 2.9 to 5.1). The control population is the total population of Tyrol (630,000 inhabitants).

  10. Combined processing of lead concentrates

    NASA Astrophysics Data System (ADS)

    Kubasov, V. L.; Paretskii, V. M.; Sidorin, G. N.; Travkin, V. F.

    2013-06-01

    A combined scheme of processing of lead concentrates with the production of pure metallic lead and the important components containing in these concentrates is considered. This scheme includes sulfating roasting of the lead concentrates and two-stage leaching of the formed cinder with the formation of a sulfate solution and lead sulfate. When transformed into a carbonate form, lead sulfate is used for the production of pure metallic lead. Silver, indium, copper, cadmium, nickel, cobalt, and other important components are separately extracted from a solution. At the last stage, zinc is extracted by either extraction followed by electrolytic extraction of a metal or the return of the forming solution of sulfuric acid to cinder leaching.

  11. [Adiponectin concentrations during menstrual cycle].

    PubMed

    Galván, Rosa E; Basurto, Lourdes; Saucedo, Renata; Campos, Sandra; Hernández, Marcelino; Zárate, Arturo

    2007-08-01

    Adiponectin has a direct relationship with cellular sensibility grade to insulin action. To determine adiponectin concentrations during the three phases of the menstrual cycle in young women, and to study the relationship with 17-beta estradiol and progesterone levels. Longitudinal and prospective study that included 30 normal menstruating women aged between 19 and 36 years; none had received any hormonal therapy prior to this study. Adiponectin, 17-beta estradiol, progesterone, LH and FSH were determined in blood in three phases of one menstrual cycle for each participant. Adiponectin concentrations were lower in the postovulatory phase as compared with the other two phases. Adiponectin levels did not significantly correlate with 17-beta estradiol and progesterone. Adiponectin blood levels are variable during the menstrual cycle, but the lower concentrations are observed in the postovulatory period that could be associated with other metabolic processes, such as insulin resistance.

  12. Miniaturized Cassegrainian concentrator concept demonstration

    NASA Astrophysics Data System (ADS)

    Patterson, R. E.; Rauschenbach, H. S.

    High concentration ratio photovoltaic systems for space applications have generally been considered impractical because of perceived difficulties in controlling solar cell temperatures to reasonably low values. A miniaturized concentrator system is now under development which surmounts this objection by providing acceptable solar cell temperatures using purely passive cell cooling methods. An array of identical miniaturized, rigid Cassegrainian optical systems having a low f-number with resulting short dimensions along their optical axes are rigidly mounted into a frame to form a relatively thin concentrator solar array panel. A number of such panels, approximately 1.5 centimeters thick, are wired as an array and are folded against one another for launch in a stowed configuration. Deployment on orbit is similar to the deployment of conventional planar honeycomb panel arrays or flexible blanket arrays. The miniaturized concept was conceived and studied in the 1978-80 time frame. Progress in the feasibility demonstration to date is reported.

  13. Calcium concentration dependent collagen mineralization.

    PubMed

    Niu, Xufeng; Fan, Rui; Tian, Feng; Guo, Xiaolin; Li, Ping; Feng, Qingling; Fan, Yubo

    2017-04-01

    Mineralization of collagen fibrils is a regular combination process of organic and mineral components mainly involving calcium, phosphate and collagen. We report the influence of calcium to the self-assembly of collagen by changing the concentration of calcium ion in the process of mineralization. Low concentration of calcium results in the well collagen self-assembly while poor mineral crystallization. Relatively, high concentration of calcium can hinder collagen self-assembly, whereas it is benefited to mineral crystallization. We also reveal that collagen self-assembly happens in advance of the formation of better mineral crystals. These results interpret the mechanism of collagen mineralization further. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Autonomous pump against concentration gradient

    PubMed Central

    Xu, Zhi-cheng; Zheng, Dong-qin; Ai, Bao-quan; Zhong, Wei-rong

    2016-01-01

    Using non-equilibrium molecular dynamics and Monte Carlo methods, we have studied the molecular transport in asymmetric nanochannels. The efficiency of the molecular pump depends on the angle and apertures of the asymmetric channel, the environmental temperature and average concentration of the particles. The pumping effect can be explained as the competition between the molecular force field and the thermal disturbance. Our results provide a green approach for pumping fluid particles against the concentration gradient through asymmetric nanoscale thin films without any external forces. It indicates that pumping vacuum can be a spontaneous process. PMID:26996204

  15. Measuring Hydrogen Concentrations in Metals

    NASA Technical Reports Server (NTRS)

    Danford, M. D.

    1985-01-01

    Commercial corrosion-measurement system adapted to electrochemical determination of hydrogen concentrations in metals. New technique based on diffusion of hydrogen through foil specimen of metal. In sample holder, hydrogen produced on one side of foil, either by corrosion reaction or by cathodic current. Hydrogen diffused through foil removed on other side by constant anode potential, which leads to oxidation of hydrogen to water. Anode current is measure of concentration of hydrogen diffusing through foil. System used to study hydrogen uptake, hydrogen elimination by baking, effect of heat treatment, and effect of electroplating on high-strength steels.

  16. Energy 101: Concentrating Solar Power

    ScienceCinema

    None

    2016-07-12

    From towers to dishes to linear mirrors to troughs, concentrating solar power (CSP) technologies reflect and collect solar heat to generate electricity. A single CSP plant can generate enough power for about 90,000 homes. This video explains what CSP is, how it works, and how systems like parabolic troughs produce renewable power. For more information on the Office of Energy Efficiency and Renewable Energy's CSP research, see the Solar Energy Technology Program's Concentrating Solar Power Web page at http://www1.eere.energy.gov/solar/csp_program.html.

  17. Measuring Hydrogen Concentrations in Metals

    NASA Technical Reports Server (NTRS)

    Danford, M. D.

    1985-01-01

    Commercial corrosion-measurement system adapted to electrochemical determination of hydrogen concentrations in metals. New technique based on diffusion of hydrogen through foil specimen of metal. In sample holder, hydrogen produced on one side of foil, either by corrosion reaction or by cathodic current. Hydrogen diffused through foil removed on other side by constant anode potential, which leads to oxidation of hydrogen to water. Anode current is measure of concentration of hydrogen diffusing through foil. System used to study hydrogen uptake, hydrogen elimination by baking, effect of heat treatment, and effect of electroplating on high-strength steels.

  18. Comparative performance of membrane filters vs. high-surface area filtration cartridges for the determination of element concentrations in freshwater systems.

    PubMed

    Vignati, Dauide A L; Loizeau, Jean-Luc; Rossé, Patrick; Dominik, Janusz

    2006-03-01

    Interdisciplinary studies on trace element cycles in aquatic environments may require the simultaneous use of small- and large-scale filtration devices to collect all the necessary sample aliquots for the different scientific objectives (e.g. trace element and organic carbon analysis, chronic toxicity testing, and characterization of colloidal matter). This study compares the performance of membrane filters (MF, Millipore-approx. surface area 0.002 m2) and two large-surface area filtration cartridges (Calyx, MSI and Polypro, CUNO approx. surface area 1 m2) in three freshwater systems with contrasting characteristics. Membrane filters and filtration cartridges fractionate water samples in a comparable way except for some elements (Al, Mn, Pb, and Ti) and when dealing with high-turbidity, organic-rich matrices. Estimation of the actual filters' pore size using the single particle counting technique gives cut-offs of 0.2-0.3, 0.7 and 2 microm for membrane filters, Polypro cartridge and Calyx cartridge respectively, explaining many of the differences observed between membrane and cartridge filters. Direct involvement of filter manufacturers to determine actual filter cut-offs during environmental applications would be highly beneficial to increase the comparability of the measurements of filterable element concentrations. Better harmonization of filtration procedures (filter type, actual filter cut-off, in situ vs. ex situ filtration) among laboratories in different countries is also necessary in order to improve consistency of environmental databases.

  19. TRENDS IN RURAL SULFUR CONCENTRATIONS

    EPA Science Inventory

    This paper presents an analysis of regional trends in atmospheric concentrations in sulfur dioxide (502) and particulate sulfate (50~- ) at rural monitoring sites in the Clean Air Act Status and Trends Monitoring Network (CAsTNet) from 1990 to 1999. A two-stage approach is used t...

  20. Compact Concentrators for Solar Cells

    NASA Technical Reports Server (NTRS)

    Whang, V. S.

    1984-01-01

    Each cell in array has own concentrator. A Cassegrain Reflector combination of paraboloidal and hyperboloidar mirrors-used with conical reflector at each element of array. Three components direct light to small solar cell. No cooling fins, fans, pumps, or heat pipes needed, not even in vacuum.

  1. Spectrophotometric determination of protein concentration.

    PubMed

    Simonian, Michael H

    2004-09-01

    This unit describes spectrophotometric and colorimetric methods for measuring the concentration of a sample protein in solution. Absorbance measured at 280 nm (A(280)) is used to calculate protein concentration by comparison with a standard curve or published absorptivity values for that protein (a(280)). Alternatively, absorbance measured at 205 nm (A(205)) is used to calculate the protein concentration. The A(280) and A(205) methods can be used to quantify total protein in crude lysates and purified or partially purified protein. A spectrofluorometer or a filter fluorometer can be used to measure the intrinsic fluorescence emission of a sample solution; this value is compared with the emissions from standard solutions to determine the sample concentration. The fluorescence emission method is used to quantify purified protein. This simple method is useful for dilute protein samples and can be completed in a short amount of time. There are two colorimetric methods: the Bradford colorimetric method, based upon binding of the dye Coomassie brilliant blue to the protein of interest, and the Lowry method, which measures colorimetric reaction of tyrosyl residues in the protein sample.

  2. Gravimetric determination of phospholipid concentration.

    PubMed

    Tejera-Garcia, Roberto; Connell, Lisa; Shaw, Walter A; Kinnunen, Paavo K J

    2012-09-01

    Accurate determination of lipid concentrations is an obligatory routine in a research laboratory engaged in studies using this class of biomaterials. For phospholipids, this is frequently accomplished using the phosphate assay (Bartlett, G.R. Phosphorus Assay in Column Chromatography. J. Biol. Chem. 234, 466-468, 1959). Given the purity of the currently commercially available synthetic and isolated natural lipids, we have observed that determination of the dry weight of lipid stock solutions provides the fastest, most accurate, and generic method to assay their concentrations. The protocol described here takes advantage of the high resolution and accuracy obtained by modern weighing technology. We assayed by this technique the concentrations of a number of phosphatidylcholine samples, with different degrees of acyl chain saturation and length, and in different organic solvents. The results were compared with those from Bartlett assay, (31)P NMR, and Langmuir compression isotherms. The data obtained show that the gravimetric assay yields lipid concentrations with a resolution similar or better than obtained by the other techniques. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  3. Segmented holographic spectrum splitting concentrator

    NASA Astrophysics Data System (ADS)

    Ayala, Silvana P.; Vorndran, Shelby; Wu, Yuechen; Chrysler, Benjamin; Kostuk, Raymond K.

    2016-09-01

    This paper presents a segmented parabolic concentrator employing holographic spectral filters that provide focusing and spectral bandwidth separation capability to the system. Strips of low band gap silicon photovoltaic (PV) cells are formed into a parabolic surface as shown by Holman et. al. [1]. The surface of the PV segments is covered with holographic elements formed in dichromated gelatin. The holographic elements are designed to transmit longer wavelengths to silicon cells, and to reflect short wavelength light towards a secondary collector where high-bandgap PV cells are mounted. The system can be optimized for different combinations of diffuse and direct solar illumination conditions for particular geographical locations by controlling the concentration ratio and filtering properties of the holographic elements. In addition, the reflectivity of the back contact of the silicon cells is used to increase the optical path length and light trapping. This potentially allows the use of thin film silicon for the low bandgap PV cell material. The optical design combines the focusing properties of the parabolic concentrator and the holographic element to control the concentration ratio and uniformity of the spectral distribution at the high bandgap cell location. The presentation concludes with a comparison of different spectrum splitting holographic filter materials for this application.

  4. Flow properties of concentrated suspensions

    NASA Technical Reports Server (NTRS)

    Hattori, K.; Izumi, K.

    1984-01-01

    The viscosity and flow behavior of a concentrated suspension, with special emphasis on fresh concrete containing a superplasticizer, is analyzed according to Newton's law of viscosity. The authors interpreted Newton's law in a new way, and explain non-Newton flow from Newton's law. The outline of this new theory is given. Viscosity of suspensions, and the effect of dispersants are analyzed.

  5. Mercury concentration in cord blood.

    PubMed Central

    Spencer, D A; House, I M; Tripp, J H; Stimmler, L

    1988-01-01

    The mean mercury concentration measured in cord blood from 51 inner city babies born at Guy's Hospital was significantly higher (37 nmol/l v 20 nmol/l) than that from 17 babies born at the Royal Devon and Exeter Hospital, which serves a more rural population. PMID:3348671

  6. Viscoelasticity of Concentrated Proteoglycan Solutions

    NASA Astrophysics Data System (ADS)

    Meechai, Nispa; Jamieson, Alex; Blackwell, John; Carrino, David

    2001-03-01

    Proteoglycan Aggregate (PGA) is the principal macromolecular component of the energy-absorbing matrix of cartilage and tendon. Its brush-like supramolecular structure consists of highly-ionic subunits, non-covalently bound to a hyaluronate chain. We report viscoelastic behavior of concentrated solutions of PGA, purified by column fractionation to remove free subunits. At physiological ionic strength, these preparations exhibit a sol-to-gel transition when the concentration is increased above molecular overlap. The strain dependence of concentrated solutions shows a pronounced non-linearity above a critical strain, at which the storage modulus decreases suddenly, and the loss modulus exhibits a maximum. This response is similar to that observed for close-packed dispersions of soft spheres, when the applied strain is sufficient to move a sphere past its neighbors. At low and high ionic strength, the elasticity of solutions near the overlap concentration decreases. The former is interpreted as due to a decrease in intramolecular and intermolecular electrostatic repulsions, because of strong trapping of counterions within the PGA brush, the latter to salt-induced brush collapse.

  7. Compact Concentrators for Solar Cells

    NASA Technical Reports Server (NTRS)

    Whang, V. S.

    1984-01-01

    Each cell in array has own concentrator. A Cassegrain Reflector combination of paraboloidal and hyperboloidar mirrors-used with conical reflector at each element of array. Three components direct light to small solar cell. No cooling fins, fans, pumps, or heat pipes needed, not even in vacuum.

  8. Conglomeration, Concentration, and the Media.

    ERIC Educational Resources Information Center

    Bagdikian, Ben H.

    1980-01-01

    Outlines the concentration of control of the news media, particularly newspapers in the United States. Discusses the influence of the constituencies of daily newspapers (the reader, the advertiser, and the stock market) in terms of their control of public information. (JMF)

  9. City scale pollen concentration variability

    NASA Astrophysics Data System (ADS)

    van der Molen, Michiel; van Vliet, Arnold; Krol, Maarten

    2016-04-01

    Pollen are emitted in the atmosphere both in the country-side and in cities. Yet the majority of the population is exposed to pollen in cities. Allergic reactions may be induced by short-term exposure to pollen. This raises the question how variable pollen concentration in cities are in temporally and spatially, and how much of the pollen in cities are actually produced in the urban region itself. We built a high resolution (1 × 1 km) pollen dispersion model based on WRF-Chem to study a city's pollen budget and the spatial and temporal variability in concentration. It shows that the concentrations are highly variable, as a result of source distribution, wind direction and boundary layer mixing, as well as the release rate as a function of temperature, turbulence intensity and humidity. Hay Fever Forecasts based on such high resolution emission and physical dispersion modelling surpass traditional hay fever warning methods based on temperature sum methods. The model gives new insights in concentration variability, personal and community level exposure and prevention. The model will be developped into a new forecast tool to serve allergic people to minimize their exposure and reduce nuisance, coast of medication and sick leave. This is an innovative approach in hay fever warning systems.

  10. Concentrated Placement of Student Teachers.

    ERIC Educational Resources Information Center

    Augenstein, Mildred B.; Tennis, Melvin H., Jr.

    During the 1968-69 school year the Dade County, Florida, Public Schools conducted an experiment in which student teachers were placed in concentrated numbers among selected schools. The program involved 15 elementary and secondary schools as experimental student-teaching centers into which 212 student teachers were placed from the University of…

  11. TRENDS IN RURAL SULFUR CONCENTRATIONS

    EPA Science Inventory

    This paper presents an analysis of regional trends in atmospheric concentrations in sulfur dioxide (502) and particulate sulfate (50~- ) at rural monitoring sites in the Clean Air Act Status and Trends Monitoring Network (CAsTNet) from 1990 to 1999. A two-stage approach is used t...

  12. Cesium Concentration in MCU Solvent

    SciTech Connect

    Walker, D

    2006-01-18

    During Modular Caustic-Side Solvent Extraction (CSSX) Unit (MCU) operations, Cs-137 concentrations in product streams will vary depending on the location in the process and on the recent process conditions. Calculations of cesium concentrations under a variety of operating conditions reveal the following: (1) Under nominal operations with salt solution feed containing 1.1 Ci Cs-137 per gallon, the maximum Cs-137 concentration in the process will occur in the strip effluent (SE) and equal 15-16.5 Ci/gal. (2) Under these conditions, the majority of the solvent will contain 0.005 to 0.01 Ci/gal, with a limited portion of the solvent in the contactor stages containing {approx}4 Ci/gal. (3) When operating conditions yield product near 0.1 Ci Cs-137/gal in the decontaminated salt solution (DSS), the SE cesium concentration will be the same or lower than in nominal operations, but majority of the stripped solvent will increase to {approx}2-3 Ci/gal. (4) Deviations in strip and waste stream flow rates cause the largest variations in cesium content: (a) If strip flow rates deviate by -30% of nominal, the SE will contain {approx}23 Ci/gal, although the cesium content of the solvent will increase to only 0.03 Ci/gal; (b) If strip flow rate deviates by -77% (i.e., 23% of nominal), the SE will contain 54 Ci/gal and solvent will contain 1.65 Ci/gal. At this point, the product DSS will just reach the limit of 0.1 Ci/gal, causing the DSS gamma monitors to alarm; and (c) Moderate (+10 to +30%) deviations in waste flow rate cause approximately proportional increases in the SE and solvent cesium concentrations. Recovery from a process failure due to poor cesium stripping can achieve any low cesium concentration required. Passing the solvent back through the contactors while recycling DSS product will produce a {approx}70% reduction during one pass through the contactors (assuming the stripping D value is no worse than 0.36). If the solvent is returned to the solvent hold tank

  13. Optical Properties of Concentrated Dispersions.

    NASA Astrophysics Data System (ADS)

    Molloy, Peter J.

    Available from UMI in association with The British Library. Apparatus and methods have been developed to measure the diffuse transmittance T and reflectance R of multiple scattering, concentrated, colloidal dispersions. The variation of R and T with pathlength, wavelength, and concentration has been investigated for non-spherical particles in concentrated dispersions, over a range of pH and surfactant concentrations. Measurements of diffuse transmittance and reflectance required large corrections to be made for the presence of any specular interfaces i.e. windows. These corrections were minimised by developing a bifurcated fibre optic bundle reflectance method, which allowed R and T to be measured at volume fractions up to at least 0.3. Using magnetic, acoustic and shear fields to align the non-spherical kaolinite particles changes in R and T were measured at volume fractions upto 0.3. The amplitude of the changes and the relaxation of the changes induced by the applied fields were measured. The amplitude of the change was found to vary strongly with pH and surfactant concentration. For any particular face diameter platelet, the amplitude of the change followed closely the flocculation process, and was sensitive to the mode of particle-particle aggregation, e.g. face-face, or face-edge. The amount of surfactant per unit mass of kaolinite required to stabilise dispersions is found to vary with particle size and concentration. This showed that information about particle orientation can be obtained through multiple scattering systems when subjected to an aligning field. Kubelka-Munk two flux theory was used to relate R and T to the diffuse flux scattering parameter S. A simple theory was developed relating S to the size shape and orientation of the non-spherical particles, hence allowing the particle orientation to be determined for any aligning field. The insight into particle behaviour given by the optical method is superior to that given by rheology alone, which

  14. Ancient dissolved methane in inland waters at low concentrations revealed by a new collection method for radiocarbon (^{14}C) analysis

    NASA Astrophysics Data System (ADS)

    Dean, Joshua F.; Billett, Michael F.; Murray, Callum; Garnett, Mark H.

    2017-04-01

    Methane (CH4) is a powerful greenhouse gas and is released to the atmosphere from freshwater systems in numerous biomes globally. Radiocarbon (14C) analysis of methane can provide unique information about its age, source and rate of cycling in natural environments. Methane is often released from aquatic sediments in bubbles (ebullition), but dissolved methane is also present in lakes and streams at lower concentrations, and may not be of the same age or source. Obtaining sufficient non-ebullitive aquatic methane for 14C analysis remains a major technical challenge. Previous studies have shown that freshwater methane, in both dissolved and ebullitive form, can be significantly older than other forms of aquatic carbon (C), and it is therefore important to characterise this part of the terrestrial C balance. We present a novel method to capture sufficient amounts of dissolved methane from freshwater environments for 14C analysis by circulating water across a hydrophobic, gas-permeable membrane and collecting the methane in a large collapsible vessel. The results of laboratory and field tests show that reliable dissolved δ13CH4 and 14CH4 samples can be readily collected over short time periods (˜4 to 24 hours), at relatively low cost and from a variety of surface water types. The initial results further support previous findings that dissolved methane can be significantly older than other forms of aquatic C, especially in organic-rich catchments, and is currently unaccounted for in many terrestrial C balances and models. This method is suitable for use in remote locations, and could potentially be used to detect the leakage of unique 14CH4 signatures from point sources into waterways, e.g. coal seam gas and landfill gas.

  15. Silicon concentrator solar cell research

    SciTech Connect

    Green, M.A.; Zhao, J.; Wang, A.; Dai, X.; Milne, A.; Cai, S.; Aberle, A.; Wenham, S.R.

    1993-06-01

    This report describes work conducted between December 1990 and May 1992 continuing research on silicon concentrator solar cells. The objectives of the work were to improve the performance of high-efficiency cells upon p-type substrates, to investigate the ultraviolet stability of such cells, to develop concentrator cells based on n-type substrates, and to transfer technology to appropriate commercial environments. Key results include the identification of contact resistance between boron-defused areas and rear aluminum as the source of anomalously large series resistance in both p- and n-type cells. A major achievement of the present project was the successful transfer of cell technology to both Applied Solar Energy Corporation and Solarex Corporation.

  16. Cylindrical acoustic levitator/concentrator

    DOEpatents

    Kaduchak, Gregory; Sinha, Dipen N.

    2002-01-01

    A low-power, inexpensive acoustic apparatus for levitation and/or concentration of aerosols and small liquid/solid samples having particulates up to several millimeters in diameter in air or other fluids is described. It is constructed from a commercially available, hollow cylindrical piezoelectric crystal which has been modified to tune the resonance frequency of the breathing mode resonance of the crystal to that of the interior cavity of the cylinder. When the resonance frequency of the interior cylindrical cavity is matched to the breathing mode resonance of the cylindrical piezoelectric transducer, the acoustic efficiency for establishing a standing wave pattern in the cavity is high. The cylinder does not require accurate alignment of a resonant cavity. Water droplets having diameters greater than 1 mm have been levitated against the force of gravity using; less than 1 W of input electrical power. Concentration of aerosol particles in air is also demonstrated.

  17. PV concentrator array power costs

    SciTech Connect

    Maish, A.B.

    1983-01-01

    Photovoltaic concentrator array installed costs per adjusted peak watt (W/sub ap/) have been developed for three leading tracking structure designs using current and expected concentrator module performance. Total installed costs are presented for the arrays for 10/sup 5/m/sup 2//y production and 500 kW/sub p/ field sizes. Array field annual performance and power costs are developed as a function of array spacing using the results of a detailed computer performance code which includes the effects of array shading, series/parallel wiring, bypass diode, maximum power tracking, and PCU voltage limitations. Results indicate installed costs of the three arrays are within 10% of each other. Installed power costs are relatively insensitive to array spacing and are approximately $4/W/sub ap/ with current technology and can be expected to drop to $3 to $3.50/W/sub ap/ with array cost reductions and cell efficiency improvements.

  18. Plasmonic quantum dot solar concentrator

    NASA Astrophysics Data System (ADS)

    Chandra, S.; Ahmed, H.; Doran, J.; McCormack, S. J.

    2017-02-01

    The quantum dot solar concentrator optical efficiency is undermined by the parameters of re-absorption, scattering, and escape cone losses. These losses can be address through enhancing quantum dot (QDs) absorption and emission. This have been achieved through plasmonic coupling between QDs and gold nanoparticles (Au NPs). The plasmonic composite of various concertation of QDs and Au NPs were studied. The spacing between QDs and Au NPs is controlled through concentration distribution of both QD and Au NPs in the plasmonic composite, and it showed a significant increase in absorption and which is more pronounced for higher spectral overlap of QDs and surface plasmon resonance (SPR) frequency. The optimum plasmonic coupling showed a 17 % increase in the fluorescence emission for QDs in plasmonic composite. The results have shown significant enhancement in absorption, fluorescence emission for the p-QDSC.

  19. Nanocrystals for luminescent solar concentrators.

    PubMed

    Bradshaw, Liam R; Knowles, Kathryn E; McDowall, Stephen; Gamelin, Daniel R

    2015-02-11

    Luminescent solar concentrators (LSCs) harvest sunlight over large areas and concentrate this energy onto photovoltaics or for other uses by transporting photons through macroscopic waveguides. Although attractive for lowering solar energy costs, LSCs remain severely limited by luminophore reabsorption losses. Here, we report a quantitative comparison of four types of nanocrystal (NC) phosphors recently proposed to minimize reabsorption in large-scale LSCs: two nanocrystal heterostructures and two doped nanocrystals. Experimental and numerical analyses both show that even the small core absorption of the leading NC heterostructures causes major reabsorption losses at relatively short transport lengths. Doped NCs outperform the heterostructures substantially in this critical property. A new LSC phosphor is introduced, nanocrystalline Cd(1-x)Cu(x)Se, that outperforms all other leading NCs by a significant margin in both small- and large-scale LSCs under full-spectrum conditions.

  20. Electrokinetic concentration of charged molecules

    DOEpatents

    Singh, Anup K.; Neyer, David W.; Schoeniger, Joseph S.; Garguilo, Michael G.

    2002-01-01

    A method for separating and concentrating charged species from uncharged or neutral species regardless of size differential. The method uses reversible electric field induced retention of charged species, that can include molecules and molecular aggregates such as dimers, polymers, multimers, colloids, micelles, and liposomes, in volumes and on surfaces of porous materials. The retained charged species are subsequently quantitatively removed from the porous material by a pressure driven flow that passes through the retention volume and is independent of direction thus, a multi-directional flow field is not required. Uncharged species pass through the system unimpeded thus effecting a complete separation of charged and uncharged species and making possible concentration factors greater than 1000-fold.

  1. Concentrating Solar Power Fact Sheet

    SciTech Connect

    2015-12-01

    This fact sheet is an overview of the Concentrating Solar Power (CSP) subprogram at the U.S. Department of Energy SunShot Initiative. CSP is a dispatchable, renewable energy option that uses mirrors to focus and concentrate sunlight onto a receiver, from which a heat transfer fluid carries the intense thermal energy to a power block to generate electricity. CSP systems can store solar energy to be used when the sun is not shining. It will help meet the nation’s goal of making solar energy fully cost-competitive with other energy sources by the end of the decade. Worldwide, CSP activity is rapidly scaling, with approximately 10 gigawatts (GW) in various stages of operation or development. In the United States alone, nearly 2 GW of CSP are in operation.

  2. Development of concentrator solar cells

    SciTech Connect

    Not Available

    1994-08-01

    A limited pilot production run on PESC silicon solar cells for use at high concentrations (200 to 400 suns) is summarized. The front contact design of the cells was modified for operation without prismatic covers. The original objective of the contract was to systematically complete a process consolidation phase, in which all the, process improvements developed during the contract would be combined in a pilot production run. This pilot run was going to provide, a basis for estimating cell costs when produced at high throughput. Because of DOE funding limitations, the Photovoltaic Concentrator Initiative is on hold, and Applied Solar`s contract was operated at a low level of effort for most of 1993. The results obtained from the reduced scope pilot run showed the effects of discontinuous process optimization and characterization. However, the run provided valuable insight into the technical areas that can be optimized to achieve the original goals of the contract.

  3. Arsenic concentrations in Chinese coals.

    PubMed

    Wang, Mingshi; Zheng, Baoshan; Wang, Binbin; Li, Shehong; Wu, Daishe; Hu, Jun

    2006-03-15

    The arsenic concentrations in 297 coal samples were collected from the main coal-mines of 26 provinces in China were determined by molybdenum blue coloration method. These samples were collected from coals that vary widely in coal rank and coal-forming periods from the five main coal-bearing regions in China. Arsenic content in Chinese coals range between 0.24 to 71 mg/kg. The mean of the concentration of Arsenic is 6.4+/-0.5 mg/kg and the geometric mean is 4.0+/-8.5 mg/kg. The level of arsenic in China is higher in northeastern and southern provinces, but lower in northwestern provinces. The relationship between arsenic content and coal-forming period, coal rank is studied. It was observed that the arsenic contents decreases with coal rank in the order: Tertiary>Early Jurassic>Late Triassic>Late Jurassic>Middle Jurassic>Late Permian>Early Carboniferous>Middle Carboniferous>Late Carboniferous>Early Permian; It was also noted that the arsenic contents decrease in the order: Subbituminous>Anthracite>Bituminous. However, compared with the geological characteristics of coal forming region, coal rank and coal-forming period have little effect on the concentration of arsenic in Chinese coal. The average arsenic concentration of Chinese coal is lower than that of the whole world. The health problems in China derived from in coal (arsenism) are due largely to poor local life-style practices in cooking and home heating with coal rather than to high arsenic contents in the coal.

  4. REM-containing silicate concentrates

    NASA Astrophysics Data System (ADS)

    Pavlov, V. F.; Shabanova, O. V.; Pavlov, I. V.; Pavlov, M. V.; Shabanov, A. V.

    2016-01-01

    A new method of advanced complex processing of ores containing rare-earth elements (REE) is proposed to obtain porous X-ray amorphous aluminosilicate material with a stable chemical composition which concentrates oxides of rare-earth metals (REM). The ferromanganese oxide ores of Chuktukon deposit (Krasnoyarsk Region, RF) were used for the experiment. The obtained aluminosilicate material is appropriate for treatment with 5 - 15% solutions of mineral acids to leach REM.

  5. SQUID With Integral Flux Concentrator

    NASA Technical Reports Server (NTRS)

    Peters, Palmer N.; Sisk, Robert C.

    1989-01-01

    In improved superconducting quantum interference device (SQUID), change in size and shape of superconducting ring improves coupling to external signal coil and eases coil-positioning tolerances. More rugged and easier to manufacture than conventional SQUID's with comparable electrical characteristics. Thin-film superconducting flux concentrator utilizes Meissner effect to deflect magnetic field of signal coil into central hole of SQUID. Used in magnetometers, ammeters, analog-to-digital converters, and related electronic applications in which high signal-to-noise ratios required.

  6. Concentrated dispersions of therapeutic proteins

    NASA Astrophysics Data System (ADS)

    Truskett, Thomas

    2013-03-01

    In this talk, recent experiments characterizing highly concentrated dispersions of therapeutic proteins, which are of interest for at-home treatment of disease via subcutaneous injection, are discussed. In particular, evidence for protein nanocluster formation in these systems is explored. The roles of dispersion composition, pH, and experimental pathway are elucidated for several protein systems. Observed correlations between nanocluster properties, solution viscosity, and protein stability/activity, as well as prospective theoretical explanations for these behaviors, are highlighted.

  7. SQUID With Integral Flux Concentrator

    NASA Technical Reports Server (NTRS)

    Peters, Palmer N.; Sisk, Robert C.

    1989-01-01

    In improved superconducting quantum interference device (SQUID), change in size and shape of superconducting ring improves coupling to external signal coil and eases coil-positioning tolerances. More rugged and easier to manufacture than conventional SQUID's with comparable electrical characteristics. Thin-film superconducting flux concentrator utilizes Meissner effect to deflect magnetic field of signal coil into central hole of SQUID. Used in magnetometers, ammeters, analog-to-digital converters, and related electronic applications in which high signal-to-noise ratios required.

  8. Sample concentration using optical chromatography

    NASA Astrophysics Data System (ADS)

    Hart, Sean J.; Terray, Alex; Arnold, Jonathan; Leski, Tomasz A.

    2007-03-01

    Optical chromatography is a technique for the separation of particles that capitalizes on the balance between optic and fluidic forces. When microscopic particles in a fluid flow encounter a laser beam propagating in the opposite direction, they are trapped axially along the beam. They are then optically pushed upstream from the laser focal point to rest at a point where the optic and fluidic forces on the particle balance. Because optical and fluid forces are sensitive to differences in the physical and chemical properties of a particle, both coarse and fine separations are possible. We describe how an optical chromatography beam directed into a tailored flow environment, has been adapted to operate as an optical filter for the concentration / bioenrichment of colloidal and biological samples. In this work, the demonstrated ability to concentrate spores of the biowarfare agent, Bacillus anthracis, may have significant impact in the biodefense arena. Application of these techniques and further design of fluidic and optical environments will allow for more specific identification, concentration and separation of many more microscopic particle and biological suspensions.

  9. Freeze concentration beats the heat

    SciTech Connect

    Rosen, J.

    1990-12-01

    This paper reports on freeze concentration (FC) which saves energy and money in packaging, shipping, and storing food products. FC---in contrast to existing heat-evaporation processes---retains volatile flavor and aroma compounds in food products so that no additives are required to restore the taste and smell of the original product. In recent tests on orange, grapefruit, and pineapple juices, reconstituted FC juices were found to be superior in taste to juices produced by evaporation and similar to the original pasteurized juices. The dairy industry, which is the largest user of energy for concentration in the food sector, is looking to FC for new products such as frozen concentrated milk as well as better use of the milk by-products of cheese production. The biggest potential for new FC applications is in those industries that consume large amounts of energy for separation processing, according to a 1987 report prepared for EPRI. In the food industry, this includes milk, vinegar, and beer producers. Potential applications also abound in the pulp and paper, pharmaceutical, chemical, and petroleum industries. FC separates substances via crystallization at substantial energy savings.

  10. Photovoltaic concentrator module improvements study

    SciTech Connect

    Levy, S.L.; Kerschen, K.A. ); Hutchison, G. ); Nowlan, M.J. )

    1991-08-01

    This report presents results of a project to design and fabricate an improved photovoltaic concentrator module. Using previous work as a baseline, this study conducted analyses and testing to select major module components and design features. The lens parquet and concentrator solar cell were selected from the highest performing, available components. A single 185X point-focus module was fabricated by the project team and tested at Sandia. Major module characteristics include a 6 by 4 compression-molded acrylic lens parquet (0.737 m{sup 2} area), twenty-four 0.2 ohms-cm, FZ, p-Si solar cells (1.56 cm{sup 2} area) soldered to ceramic substrates and copper heat spreaders, and an aluminized steel housing with corrugated bottom. This project marked the first attempt to use prismatic covers on solar cells in a high-concentration, point-focus application. Cells with 15 percent metallization were obtained, but problems with the fabrication and placement of prismatic covers on these cells lead to the decision not to use covers in the prototype module. Cell assembly fabrication, module fabrication, and module optical design activities are presented here. Test results are also presented for bare cells, cell assemblies, and module. At operating conditions of 981 watts/m{sup 2} DNI and an estimated cell temperature of 65{degrees}C, the module demonstrated an efficiency of 13.9 percent prior to stressed environmental exposure. 12 refs., 56 figs., 7 tabs.

  11. Advanced high efficiency concentrator cells

    SciTech Connect

    Gale, R. . Varian Research Center)

    1992-06-01

    This report describes research to develop the technology needed to demonstrate a monolithic, multijunction, two-terminal, concentrator solar cell with a terrestrial power conversion efficiency greater than 35%. Under three previous subcontracts, Varian developed many of the aspects of a technology needed to fabricate very high efficiency concentrator cells. The current project was aimed at exploiting the new understanding of high efficiency solar cells. Key results covered in this report are as follows. (1) A 1.93-eV AlGaAs/1.42-eV GaAs metal-interconnected cascade cell was manufactured with a one-sun efficiency at 27.6% at air mass 1.5 (AM1.5) global. (2) A 1.0eV InGaAs cell was fabricated on the reverse'' side of a low-doped GaAs substrate with a one-sun efficiency of 2.5% AM1.5 diffuse and a short-circuit current of 14.4 mA/cm{sup 2}. (3) Small-scale manufacturing of GaAs p/n concentrator cells was attempted and obtained an excellent yield of high-efficiency cells. (4) Grown-in tunnel junction cell interconnects that are transparent and thermally stable using C and Si dopants were developed. 10 refs.

  12. Purification and concentration of alphavirus.

    PubMed

    Lundstrom, Kenneth

    2012-07-01

    The alphaviruses Semliki Forest virus and Sindbis virus have been used frequently as expression vectors in vitro and in vivo. Usually, these systems consist of replication-deficient vectors that require a helper vector for packaging of recombinant particles. Replication-proficient vectors have also been engineered. Alphaviral vectors can be used as nucleic-acid-based vectors (DNA and RNA) or infectious particles. High-titer viral production is achieved in <2 d. The broad host range of alphaviruses facilitates studies in mammalian and nonmammalian cell lines, primary cells in culture, and in vivo. The strong preference for expression in neuronal cells has made alphaviruses particularly useful in neurobiological studies. Unfortunately, their strong cytotoxic effect on host cells, relatively short-term transient expression patterns, and the reasonably high cost of viral production remain drawbacks. However, novel mutant alphaviruses have showed reduced cytotoxicity and prolonged expression. Membrane proteins (which are generally difficult to express at high levels in recombinant systems) have generated high yields and facilitate applications in structural biology. Alphaviruses have also been applied in vaccine development and gene therapy. Generally, purification or concentration of alphaviruses is not necessary. However, for instance, the medium derived from baby hamster kidney cells is toxic to primary neurons in culture. Including a purification step substantially improves the survival of the transduced neurons. Viral concentration and purification may also be advantageous for in vivo studies in animal models and are mandatory for clinical applications. This protocol describes three methods for purification and concentration of alphavirus.

  13. Window-Integrated Low Concentration Planar Light Guide Solar Concentrators

    NASA Astrophysics Data System (ADS)

    Williams, Daniel James Lawler

    Several novel low concentration solar concentrator photovoltaic designs are presented, based on the planar light guide architecture pioneered by the University of Rochester. These systems are designed for integration into windows, requiring them to be stationary and to have a large acceptance angle since they cannot move to track the sun. The application goal is to use solar generated electricity to offset the energy lost through the window during cold times of the year. The systems are evaluated for their effective insulation properties given the calculated net energy lost. Without moving parts, they optimize to have acceptance angles of about 20° to 35° in the vertical direction and +/-90° in the horizontal direction, but have peak optical efficiencies of less than 50%. By including internally moving parts, the acceptance angle is increased to nearly a full pi steradians (the full sky from the point of view of the window) and the average optical efficiency increases to over 50%. Systems in certain locations are not viable due to low solar irradiance in the wintertime, e.g., Rochester, NY. Others, however, reduce net energy loss to zero for much of the year. A prototype of one of the systems is fabricated, measured, and modeled. The simulated and measured performance data are compared and are in close agreement, validating the model and the evaluation methods used during system optimization.

  14. Predicting indoor radon-222 concentration

    SciTech Connect

    Stowe, M.H.

    1994-12-31

    Radon, a cause of lung cancer among miners, is being investigated as a source of lung cancer in the general population due to long-term low-level exposures in residences. Assessment of cumulative residential radon exposure entails measurements in past residences, some of which no longer exist or are not accessible. Estimates of radon concentrations in these missing homes are necessary for analysis of the radon-lung cancer association. Various approaches have been used by researchers attempting to predict the distribution of radon measurements in homes from specified geological and building characteristics. This study has modelled the set of basement radon measurements of 3788 Connecticut homes with several of these approaches, in addition to a descriptive tree method not previously utilized, and compared their validity on a random subset of homes not used in model construction. Each geographical and geological variable was more predictive of radon concentration than any of the housing characteristics. The single variable which explained the largest fraction of the variability in radon readings was the mean radon concentration for the zipcode area in which the house was located (R{sup 2} = .157). Soil characteristics at individual housing sites were not available for these analyses. They would be expected to increase the predictive power of the models. Multiple regression models, both additive and multiplicative, were not able to explain more than 22% of the variation in radon readings. Variables found to be significant in these models were zipcode mean, residential radon mean of bedrock unit, building age, type of foundation walls, type of water supply, aeroradioactivity reading, and lithology of the bedrock. A site potential index, based upon a classification of the bedrock underlying the house, was a better predictor of indoor radon level than other single geological variables, yet only explained 8% of the radon variability.

  15. Concentrating Solar Power Program overview

    SciTech Connect

    1998-04-01

    Over the last decade, the US solar thermal industry has established a track record in the power industry by building and operating utility-scale power plants with a combined rated capacity of 354 megawatts (MW). The technology used in these power plants is based on years of research and development (R and D), much of it sponsored by the US Department of Energy (DOE). DOE`s Concentrating Solar Power (CSP) Program is collaborating with its partners in the private sector to develop two new solar technologies -- power towers and dish/engines -- to meet the huge commercial potential for solar power.

  16. Solar concentrator advanced development project

    NASA Technical Reports Server (NTRS)

    Corrigan, Robert D.; Ehresman, Derik T.

    1987-01-01

    A solar dynamic concentrator design developed for use with a solar-thermodynamic power generation module intended for the Space Station is considered. The truss hexagonal panel reflector uses a modular design approach and is flexible in attainable flux profiles and assembly techniques. Preliminary structural, thermal, and optical analysis results are discussed. Accuracy of the surface reflectors should be within 5 mrad rms slope error, resulting in the need for close fabrication tolerances. Significant fabrication issues to be addressed include the facet reflective and protective coating processes and the surface specularity requirements.

  17. Concentrator testing using projected images

    NASA Technical Reports Server (NTRS)

    Jefferies, Kent S.

    1991-01-01

    The projected image system can be used to evaluate concentrator optical properties by comparing images reflected onto the ceiling of the test facility to theoretical facet outlines. This system was tested by comparing ceiling images to facet outlines computed using facet characteristics measured by the digital image radiometer (DIR) optical measuring system. The agreement was good, confirming the accuracy of both optical systems. Six facets were mounted in the centers of the pie sectors of one hexagonal panel. Differences between the facets and facet nonsymmetries were observed in photographs of the ceiling images of these facets.

  18. Concentrator testing using projected images

    NASA Technical Reports Server (NTRS)

    Jefferies, Kent S.

    1991-01-01

    The projected image system can be used to evaluate concentrator optical properties by comparing images reflected onto the ceiling of the test facility to theoretical facet outlines. This system was tested by comparing ceiling images to facet outlines computed using facet characteristics measured by the digital-image-radiometer (DIR) optical measuring system. The agreement was good, confirming the accuracy of both optical systems. Six facets were mounted in the centers of the pie sectors of one hexagonal panel. Differences between the facets and facet nonsymmetries were observed in photographs of the ceiling images of the facets.

  19. Concentrator testing using projected images

    NASA Astrophysics Data System (ADS)

    Jefferies, Kent S.

    The projected image system can be used to evaluate concentrator optical properties by comparing images reflected onto the ceiling of the test facility to theoretical facet outlines. This system was tested by comparing ceiling images to facet outlines computed using facet characteristics measured by the digital-image-radiometer (DIR) optical measuring system. The agreement was good, confirming the accuracy of both optical systems. Six facets were mounted in the centers of the pie sectors of one hexagonal panel. Differences between the facets and facet nonsymmetries were observed in photographs of the ceiling images of the facets.

  20. Nitrate concentrations under irrigated agriculture

    USGS Publications Warehouse

    Zaporozec, A.

    1983-01-01

    In recent years, considerable interest has been expressed in the nitrate content of water supplies. The most notable toxic effect of nitrate is infant methemoglobinemia. The risk of this disease increases significantly at nitrate-nitrogen levels exceeding 10 mg/l. For this reason, this concentration has been established as a limit for drinking water in many countries. In natural waters, nitrate is a minor ionic constituent and seldom accounts for more than a few percent of the total anions. However, nitrate in a significant concentration may occur in the vicinity of some point sources such as septic tanks, manure pits, and waste-disposal sites. Non-point sources contributing to groundwater pollution are numerous and a majority of them are related to agricultural activities. The largest single anthropogenic input of nitrate into the groundwater is fertilizer. Even though it has not been proven that nitrogen fertilizers are responsible for much of nitrate pollution, they are generally recognized as the main threat to groundwater quality, especially when inefficiently applied to irrigated fields on sandy soils. The biggest challenge facing today's agriculture is to maintain the balance between the enhancement of crop productivity and the risk of groundwater pollution. ?? 1982 Springer-Verlag New York Inc.

  1. Airborne concentrations of peanut protein.

    PubMed

    Johnson, Rodney M; Barnes, Charles S

    2013-01-01

    Food allergy to peanut is a significant health problem, and there are reported allergic reactions to peanuts despite not eating or having physical contact with peanuts. It is presumed that an allergic reaction may have occurred from inhalation of airborne peanut allergens. The purpose of this study was to detect the possible concentrations of airborne peanut proteins for various preparations and during specific activities. Separate Ara h 1 and Ara h 2 monoclonal enzyme-linked immunosorbent assays and a polyclonal sandwich enzyme immunoassay for peanuts were used to detect the amount of airborne peanut protein collected using a Spincon Omni 3000 air collector (Sceptor Industries, Inc., Kansas City, MO) under different peanut preparation methods and situations. Air samples were measured for multiple peanut preparations and scenarios. Detectable amounts of airborne peanut protein were measured using a whole peanut immunoassay when removing the shells of roasted peanut. No airborne peanut allergen (Ara h 1 or Ara h 2) or whole peanut protein above the LLD was measured in any of the other peanut preparation collections. Ara h 1, Ara h 2, and polyclonal peanut proteins were detected from water used to boil peanuts. Small amounts of airborne peanut protein were detected in the scenario of removing shells from roasted peanuts; however, Ara h 1 and Ara h 2 proteins were unable to be consistently detected. Although airborne peanut proteins were detected, the concentration of airborne peanut protein that is necessary to elicit a clinical allergic reaction is unknown.

  2. Sertraline concentrations and postmortem redistribution.

    PubMed

    McIntyre, Iain M; Mallett, Phyllis

    2012-11-30

    Sertraline is a commonly prescribed selective inhibitor of serotonin uptake used for the treatment of mental depression and anxiety. Central blood and liver concentrations of sertraline (norsertraline) are compared to levels in peripheral blood in nine medical examiner cases. Specimens were initially screened for alcohol and simple volatiles by GC-FID headspace analysis, ELISA for drugs of abuse, and alkaline drugs by GC/MS. Sertraline, when detected by the alkaline drug screen, was subsequently confirmed and quantified by a specific GC-NPD procedure. Data suggest that when ingested with other medications, sertraline may be a contributing factor in death. Sertraline (norsertraline) concentrations ranged from 0.13 (0.11) to 2.1 (6.0) mg/L in peripheral blood, from 0.18 (0.12) to 2.0 (6.7) mg/L in central blood, and 21 to 160 mg/kg in liver. Sertraline central blood to peripheral blood ratios averaged 1.22±0.85 (mean±standard deviation). The liver to peripheral blood ratios, on the other hand, were markedly higher and averaged 97±40 (mean±standard deviation). Given that a liver to peripheral blood ratio exceeding 20 is indicative of propensity for significant postmortem redistribution, these data confirm that sertraline is prone to marked postmortem redistribution.

  3. Osmotic pressure beyond concentration restrictions.

    PubMed

    Grattoni, Alessandro; Merlo, Manuele; Ferrari, Mauro

    2007-10-11

    Osmosis is a fundamental physical process that involves the transit of solvent molecules across a membrane separating two liquid solutions. Osmosis plays a role in many biological processes such as fluid exchange in animal cells (Cell Biochem. Biophys. 2005, 42, 277-345;1 J. Periodontol. 2007, 78, 757-7632) and water transport in plants. It is also involved in many technological applications such as drug delivery systems (Crit. Rev. Ther. Drug. 2004, 21, 477-520;3 J. Micro-Electromech. Syst. 2004, 13, 75-824) and water purification. Extensive attention has been dedicated in the past to the modeling of osmosis, starting with the classical theories of van't Hoff and Morse. These are predictive, in the sense that they do not involve adjustable parameters; however, they are directly applicable only to limited regimes of dilute solute concentrations. Extensions beyond the domains of validity of these classical theories have required recourse to fitting parameters, transitioning therefore to semiempirical, or nonpredictive models. A novel approach was presented by Granik et al., which is not a priori restricted in concentration domains, presents no adjustable parameters, and is mechanistic, in the sense that it is based on a coupled diffusion model. In this work, we examine the validity of predictive theories of osmosis, by comparison with our new experimental results, and a meta-analysis of literature data.

  4. CAUSE OF A MULTI-SPECIES RADIOIODINE PLUME THAT IS INCREASING IN CONCENTRATION

    SciTech Connect

    Kaplan, D.

    2010-09-30

    Field and laboratory studies were carried out to understand the cause for steady increases in {sup 129}I concentrations emanating from radiological seepage basins located on the Savannah River Site. The basins were closed in 1988 by adding limestone and blast furnace slag and then capping with a RCRA low permeability engineered cover. Groundwater {sup 129}I concentrations in a well near the seepage basin in 1993 were 200 pCi L{sup -1} and are presently between 400 and 1000 pCi L{sup -1}. Iodine speciation in the plume was not uniform. Near the source, the iodine was comprised of 86% iodide, 2% iodate, and 12% organo-iodine (total activity = 178 pCi L{sup -1}). Whereas, groundwater iodine speciation 365 m down stream (25 m up stream from a wetland) was 0% iodide, 93% iodate, and 7% organo iodine. Batch desorption studies demonstrated that high concentrations of {sup 129}I could be incrementally desorbed from an archived seepage basin sediment sample by raising the pH. Batch sorption studies showed that iodate, IO{sub 3}{sup -}, sorbed more strongly than iodide, I{sup -}, to a subsurface clayey sediment, but equally well as iodide to a subsurface sandy sediment and a wetland sediment. Placing an organic-rich wetland sediment, but not nearby mineral sediments, under reducing (or microaerobic) conditions resulted in a large decrease in iodide K{sub d} values (from 73 to 10 mL g{sup -1}) and iodate K{sub d} values (from 80 to 7 mL g{sup -1}). Between pH and reduction-oxidation potential, it appears that pH seems to have a stronger influence on iodide and iodate sorption to mineral sediment. This may not be true for sediments containing higher concentrations of organic matter, such as the 7.6% organic matter sediment used in this study. First order calculations based on desorption studies with seepage basin sediments indicate that the modest increase of 0.7 pH units detected in the study site groundwater over the last 17 years since closure of the seepage basin may be

  5. Evaluation of Potential pH-Driven Metal Release Due to Elevated Groundwater CO2 Concentrations

    NASA Astrophysics Data System (ADS)

    Tinnacher, R. M.; Varadharajan, C.; Zheng, L.; Spycher, N.; Birkholzer, J. T.; Trautz, R. C.; Pugh, J. D.; Esposito, R.; Nico, P. S.

    2012-12-01

    CO2. In the absence of CO2, we observed pH shifts during lab-scale experiments, which were driven by the natural buffering and pH of sediments. Furthermore, it was determined that a large group of metals (e.g., Mg, Mn, Ni, Co) follows very similar trends, which are characterized by fast, initial metal release and higher metal concentrations mobilized from organic-rich than organic-poor sediments. For these metals, release characteristics are very comparable in the absence and presence of CO2, suggesting primarily pH-driven release processes. Currently, numerical models are developed to simulate lab and field results, and to further elucidate the underlying metal release mechanisms. Modeling results will be summarized in a companion presentation by Zheng et al.

  6. Chloramination of Concentrated Drinking Water for ...

    EPA Pesticide Factsheets

    Abstract for presentation on chloraminated drinking water concentrates to create whole DBP mixtures Abstract for presentation on chloraminating drinking water concentrates to create whole DBP mixtures

  7. Plasma leptin concentration in donkeys.

    PubMed

    Díez, E; López, I; Pérez, C; Pineda, C; Aguilera-Tejero, E

    2012-01-01

    Donkeys appear to be more predisposed than large breed horses to suffer from hyperlipemia. The reason for that predisposition is unknown but anorexia is a consistent feature of the disease. Leptin, a protein synthesized in fat tissue, is one of the major inhibitors of appetite in mammals. We hypothesized that donkeys could have elevated plasma leptin concentrations compared to horses. Blood samples were obtained from 50 donkeys for measurement of leptin, triglycerides (TGs), glucose, and insulin. Glucose/insulin ratio, modified insulin to glucose ratio, and reciprocal of the square root of insulin were calculated. Based on their body condition score (BCS), donkeys were classified as lean (n = 18), normal (n = 16), or overweight (n = 16). The results were compared with reference values from our laboratory and with a group of horses (n = 25) used as an internal control. Values of both leptin and TGs in donkeys were above the horse reference range and also significantly higher than those of the control horses: leptin (11.2 ± 1.7 versus 5.8 ± 0.5 µg/L, p < 0.05) and TGs (0.93 ± 0.1 versus 0.54 ± 0.1 mmol/L, p < 0.01). Overweight donkeys had leptin (19.3 ± 2.9 µg/L) and TG (1.3 ± 0.2 mmol/L) concentrations that were significantly (p < 0.01) higher than normal (9.4 ± 3.3 µg/L and 0.85 ± 0.1 mmol/L, respectively) and lean (5.5 ± 1.0 µg/L and 0.66 ± 0.1 mmol/L, respectively) donkeys. A significant positive correlation (p < 0.01) was found between BCS and leptin (r = 0.43), TGs (r = 0.46), glucose (r = 0.41), and insulin (r = 0.40). Donkeys have higher plasma leptin concentrations than horses and leptin is correlated with BCS.

  8. Concentric Nested Toroidal Inflatable Structures

    NASA Technical Reports Server (NTRS)

    Johnson, Christopher J.; Raboin, Jasen L.; Spexarth, Gary R.

    2010-01-01

    Assemblies comprising multiple limited- height toroidal inflatable structures nested in a concentric arrangement have been invented to obtain more design flexibility than can be obtained in single taller, wider toroidal inflatable structures (see figure). Originally intended for use as containers for habitats for humans in outer space or on remote planets, these and related prior inflatable structures could also be useful on Earth as lightweight, compactly stowable, portable special-purpose buildings that could be transported to remote locations and there inflated to full size and shape. In the case of a single inflatable toroidal structure, one important source of lack of design flexibility is the fact that an increase in outer diameter (which is sometimes desired) is necessarily accompanied by an increase in height (which is sometimes undesired). Increases in diameter and height can also cause difficulty in utilization of the resulting larger volume, in that it can become necessary to partition the volume by means of walls and floors, and features (e.g., stairs or ladders) must be added to enable vertical movement between floors. Moreover, ascending and descending between floors in a gravitational environment could pose unacceptable difficulty for the inhabitants under some circumstances. Another source of lack of design flexibility in a single toroidal inflatable structure is that for a given inflation pressure, an increase in the outer diameter of the structure necessarily entails an increase in the maximum stress in the structure. Because it is necessary to keep the maximum stress within the load-bearing capability of the structural materials, consistent with other aspects of the design, this may translate to a limit on the outer diameter. In an assembly comprising concentric nested toroidal structures, an increase in outer diameter does not necessarily entail an increase in height or a maximum stress in excess of the load-bearing capability of the structural

  9. [Concentration or decline in Puebla?].

    PubMed

    Cabrera Becerra, V

    1993-04-01

    Some doubts have been expressed over whether the slowing pace of urbanization suggested by the 1990 census of Mexico was an accurate reflection of changing conditions, or whether it resulted from some intentional or unintended bias. Comparison of data from succeeding censuses indicates that the growth rate of the city of Puebla declined from 6.32% in 1980 to 2.63% in 1990. This work argues that, in Puebla, a trend to deconcentration of the population within the city of Puebla during the 1980s was accompanied by rapid growth in smaller and medium sized nearby cities, resulting in increased overall concentration in Puebla's metropolitan area. The absolute population of the city of Puebla increased from 772,908 in 1980 to 1,007,170 in 1990. The central area of the state of Puebla, which surrounds the city, increased its share of the state population from 51.67% in 1980 to 52.21% in 1990. The number of places with over 5000 inhabitants in the area surrounding the city of Puebla increased from 27 in 1980 to 39 in 1990. Construction of the Puebla-Atlixco highway will undoubtedly attract growth to the area southwest of Puebla. Small cities to the east of Puebla have shown significant growth although their region remains strongly rural. The same process of deconcentration of population in Puebla and concentration in its surrounding metropolitan regions can probably also be detected in patterns of investment of public funds. The trend is likely to continue through the 1990s.

  10. The Rheology of Concentrated Suspensions

    SciTech Connect

    Andreas Acrivos

    2004-09-07

    Research program on the rheological properties of flowing suspensions. The primary purpose of the research supported by this grant was to study the flow characteristics of concentrated suspensions of non-colloidal solid particles and thereby construct a comprehensive and robust theoretical framework for modeling such systems quantitatively. At first glance, this seemed like a modest goal, not difficult to achieve, given that such suspensions were viewed simply as Newtonian fluids with an effective viscosity equal to the product of the viscosity of the suspending fluid times a function of the particle volume fraction. But thanks to the research findings of the Principal Investigator and of his Associates, made possible by the steady and continuous support which the PI received from the DOE Office of Basic Energy Sciences, the subject is now seen to be more complicated and therefore much more interesting in that concentrated suspensions have been shown to exhibit fascinating and unique rheological properties of their own that have no counterpart in flowing Newtonian or even non-Newtonian (polymeric) fluids. In fact, it is generally acknowledged that, as the result of these investigations for which the PI received the 2001 National Medal of Science, our understanding of how suspensions behave under flow is far more detailed and comprehensive than was the case even as recently as a decade ago. Thus, given that the flow of suspensions plays a crucial role in many diverse physical processes, our work has had a major and lasting impact in a subject having both fundamental as well as practical importance.

  11. Concentrators Enhance Solar Power Systems

    NASA Technical Reports Server (NTRS)

    2013-01-01

    "Right now, solar electric propulsion is being looked at very seriously," says Michael Piszczor, chief of the photovoltaic and power technologies branch at Glen Research Center. The reason, he explains, originates with a unique NASA mission from the late 1990s. In 1998, the Deep Space 1 spacecraft launched from Kennedy Space Center to test a dozen different space technologies, including SCARLET, or the Solar Concentrator Array with Refractive Linear Element Technology. As a solar array that focused sunlight on a smaller solar cell to generate electric power, SCARLET not only powered Deep Space 1 s instruments but also powered its ion engine, which propelled the spacecraft throughout its journey. Deep Space 1 was the first spacecraft powered by a refractive concentrator design like SCARLET, and also utilized multi-junction solar cells, or cells made of multiple layers of different materials. For the duration of its 38-month mission, SCARLET performed flawlessly, even as Deep Space 1 flew by Comet Borrelly and Asteroid Braille. "Everyone remembers the ion engine on Deep Space 1, but they tend to forget that the SCARLET array powered it," says Piszczor. "Not only did both technologies work as designed, but the synergy between the two, solar power and propulsion together, is really the important aspect of this technology demonstration mission. It was the first successful use of solar electric propulsion for primary propulsion." More than a decade later, NASA is keenly interested in using solar electric propulsion (SEP) for future space missions. A key issue is cost, and SEP has the potential to substantially reduce cost compared to conventional chemical propulsion technology. "SEP allows you to use spacecraft that are smaller, lighter, and less costly," says Piszczor. "Even though it might take longer to get somewhere using SEP, if you are willing to trade time for cost and smaller vehicles, it s a good trade." Potentially, SEP could be used on future science missions

  12. Concentric superlattice pattern in dielectric barrier discharge

    SciTech Connect

    Feng, Jianyu; Dong, Lifang Wei, Lingyan; Fan, Weili; Li, Caixia; Pan, Yuyang

    2016-09-15

    The concentric superlattice pattern with three sub-lattices is observed in the dielectric barrier discharge in air/argon for the first time. Its spatiotemporal structure investigated by an intensified charge-coupled device shows that it is an interleaving of three different sub-lattices, which are concentric-ring, concentric-framework, and concentric-dot, respectively. The images of single-frame indicate that the concentric-ring and concentric-framework are composed of individual filaments. By using the optical emission spectrum method, it is found that plasma parameters of the concentric-dot are different from those of the concentric-ring and concentric-framework. The spatiotemporal dynamics of the concentric superlattice pattern is dependent upon the effective field of the distribution of the wall charges field and the applied field.

  13. Concentric superlattice pattern in dielectric barrier discharge

    NASA Astrophysics Data System (ADS)

    Feng, Jianyu; Dong, Lifang; Wei, Lingyan; Fan, Weili; Li, Caixia; Pan, Yuyang

    2016-09-01

    The concentric superlattice pattern with three sub-lattices is observed in the dielectric barrier discharge in air/argon for the first time. Its spatiotemporal structure investigated by an intensified charge-coupled device shows that it is an interleaving of three different sub-lattices, which are concentric-ring, concentric-framework, and concentric-dot, respectively. The images of single-frame indicate that the concentric-ring and concentric-framework are composed of individual filaments. By using the optical emission spectrum method, it is found that plasma parameters of the concentric-dot are different from those of the concentric-ring and concentric-framework. The spatiotemporal dynamics of the concentric superlattice pattern is dependent upon the effective field of the distribution of the wall charges field and the applied field.

  14. Offset truss hex solar concentrator

    NASA Technical Reports Server (NTRS)

    White, John E. (Inventor); Sturgis, James D. (Inventor); Erikson, Raymond J. (Inventor); Waligroski, Gregg A. (Inventor); Scott, Michael A. (Inventor)

    1991-01-01

    A solar energy concentrator system comprises an offset reflector structure made up of a plurality of solar energy reflector panel sections interconnected with one another to form a piecewise approximation of a portion of a (parabolic) surface of revolution rotated about a prescribed focal axis. Each panel section is comprised of a plurality of reflector facets whose reflective surfaces effectively focus reflected light to preselected surface portions of the interior sidewall of a cylindrically shaped solar energy receiver. The longitudinal axis of the receiver is tilted at an acute angle with respect to the optical axis such that the distribution of focussed solar energy over the interior surface of the solar engine is optimized for dynamic solar energy conversion. Each reflector panel section comprises a flat, hexagonally shaped truss support framework and a plurality of beam members interconnecting diametrically opposed corners of the hexagonal framework recessed within which a plurality of (spherically) contoured reflector facets is disposed. The depth of the framework and the beam members is greater than the thickness of a reflector facet such that a reflector facet may be tilted (for controlling the effective focus of its reflected light through the receiver aperture) without protruding from the panel section.

  15. CONCENTRATION AND PROCESSING OF WATERBORNE ...

    EPA Pesticide Factsheets

    This chapter describes the most widely used virus adsorption-elution (VIRADEL) method for recovering human enteric viruses from water matrices (Fout et al., 1996). The method takes advantage of postively charged cartridge filters to concentrate viruses from water. The major advantage of methods that use these filters over those described in Chapters 5 and 6 that use negatively charged filters is that additives are not normally needed to achieve virus adsorption to filters. Develop sensitive techniques to detect and identify emerging human waterborne pathogenic viruses and viruses on the CCL.Determine effectiveness of viral indicators to measure microbial quality in water matrices.Support activities: (a) culture and distribution of mammalian cells for Agency and scientific community research needs, (b) provide operator expertise for research requiring confocal and electron microscopy, (c) glassware cleaning, sterilization and biological waste disposal for the Cincinnati EPA facility, (d) operation of infectious pathogenic suite, (e) maintenance of walk-in constant temperature rooms and (f) provide Giardia cysts.

  16. Concentrating Solar Power (Fact Sheet)

    SciTech Connect

    Not Available

    2011-10-01

    Concentrating Solar Power (CSP) offers a utility-scale, firm, dispatchable renewable energy option that can help meet the nation's goal of making solar energy cost competitive with other energy sources by the end of the decade. The DOE SunShot Initiative is a collaborative national initiative to make solar energy technologies cost-competitive with other forms of energy by reducing the cost of solar energy systems by about 75% by the end of the decade. Reducing the total installed cost for utility-scale solar electricity to roughly 6 cents per kilowatt hour without subsidies will result in rapid, large-scale adoption of solar electricity across the United States. Reaching this goal will re-establish American technological leadership, improve the nation's energy security, and strengthen U.S. economic competitiveness in the global clean energy race. SunShot will work to bring down the full cost of solar - including the costs of solar cells and installation by focusing on four main pillars: (1) Technologies for solar cells and arrays that convert sunlight to energy; (2) Electronics that optimize the performance of the installation; (3) Improvements in the efficiency of solar manufacturing processes; and (4) Installation, design, and permitting for solar energy systems.

  17. Continuous Flow Microfluidic Bioparticle Concentrator.

    PubMed

    Martel, Joseph M; Smith, Kyle C; Dlamini, Mcolisi; Pletcher, Kendall; Yang, Jennifer; Karabacak, Murat; Haber, Daniel A; Kapur, Ravi; Toner, Mehmet

    2015-06-10

    Innovative microfluidic technology has enabled massively parallelized and extremely efficient biological and clinical assays. Many biological applications developed and executed with traditional bulk processing techniques have been translated and streamlined through microfluidic processing with the notable exception of sample volume reduction or centrifugation, one of the most widely utilized processes in the biological sciences. We utilize the high-speed phenomenon known as inertial focusing combined with hydraulic resistance controlled multiplexed micro-siphoning allowing for the continuous concentration of suspended cells into pre-determined volumes up to more than 400 times smaller than the input with a yield routinely above 95% at a throughput of 240 ml/hour. Highlighted applications are presented for how the technology can be successfully used for live animal imaging studies, in a system to increase the efficient use of small clinical samples, and finally, as a means of macro-to-micro interfacing allowing large samples to be directly coupled to a variety of powerful microfluidic technologies.

  18. Urinary concentrating processes in vertebrates.

    PubMed Central

    Schmidt-Nielsen, B.

    1979-01-01

    Avian and mammalian kidneys can produce a urine hyperosmotic to the blood by means of a renal countercurrent system. Birds are uricotelic; mammals are ureotelic. It is proposed that the inner medulla present in mammalian, but not in avian kidneys serves specifically to accumulate urea in the inner and outer medulla. Among mammalian kidneys the degree to which urea accumulates in the inner medulla is inversely related to the complexity of the vascular bundles (in the outer medulla) and the cortical urea recycling index. A model is proposed for urea recycling via the vascular bundles. The renal pelvis varies in size among mammals. Its relative size is unrelated to the type of vascular bundles, cortical recycling index; or urea accumulation in the inner medulla. Since urine refluxes into the renal pelvis during rising urine flow only, the function of the pelvis could be that of bringing the more dilute urine into contact with the outer medulla and underlying capillaries, thereby aiding in reducing the urea concentration in outer and inner medulla during rising urine flow. The size of the renal pelvis may be related to the volume of the inner medulla. Other factors may also be involved. Images FIG. 1 FIG. 3 FIG. 5 FIG. 6 FIG. 9 FIG. 10 FIG. 11 FIG. 12 FIG. 13 PMID:538955

  19. Planar photovoltaic solar concentrator module

    DOEpatents

    Chiang, C.J.

    1992-12-01

    A planar photovoltaic concentrator module for producing an electrical signal from incident solar radiation includes an electrically insulating housing having a front wall, an opposing back wall and a hollow interior. A solar cell having electrical terminals is positioned within the interior of the housing. A planar conductor is connected with a terminal of the solar cell of the same polarity. A lens forming the front wall of the housing is operable to direct solar radiation incident to the lens into the interior of the housing. A refractive optical element in contact with the solar cell and facing the lens receives the solar radiation directed into the interior of the housing by the lens and directs the solar radiation to the solar cell to cause the solar cell to generate an electrical signal. An electrically conductive planar member is positioned in the housing to rest on the housing back wall in supporting relation with the solar cell terminal of opposite polarity. The planar member is operable to dissipate heat radiated by the solar cell as the solar cell generates an electrical signal and further forms a solar cell conductor connected with the solar cell terminal to permit the electrical signal generated by the solar cell to be measured between the planar member and the conductor. 5 figs.

  20. Planar photovoltaic solar concentrator module

    DOEpatents

    Chiang, Clement J.

    1992-01-01

    A planar photovoltaic concentrator module for producing an electrical signal from incident solar radiation includes an electrically insulating housing having a front wall, an opposing back wall and a hollow interior. A solar cell having electrical terminals is positioned within the interior of the housing. A planar conductor is connected with a terminal of the solar cell of the same polarity. A lens forming the front wall of the housing is operable to direct solar radiation incident to the lens into the interior of the housing. A refractive optical element in contact with the solar cell and facing the lens receives the solar radiation directed into the interior of the housing by the lens and directs the solar radiation to the solar cell to cause the solar cell to generate an electrical signal. An electrically conductive planar member is positioned in the housing to rest on the housing back wall in supporting relation with the solar cell terminal of opposite polarity. The planar member is operable to dissipate heat radiated by the solar cell as the solar cell generates an electrical signal and further forms a solar cell conductor connected with the solar cell terminal to permit the electrical signal generated by the solar cell to be measured between the planar member and the conductor.

  1. Planar photovoltaic solar concentrator module

    SciTech Connect

    Chiang, C.J.

    1992-12-01

    A planar photovoltaic concentrator module for producing an electrical signal from incident solar radiation includes an electrically insulating housing having a front wall, an opposing back wall and a hollow interior. A solar cell having electrical terminals is positioned within the interior of the housing. A planar conductor is connected with a terminal of the solar cell of the same polarity. A lens forming the front wall of the housing is operable to direct solar radiation incident to the lens into the interior of the housing. A refractive optical element in contact with the solar cell and facing the lens receives the solar radiation directed into the interior of the housing by the lens and directs the solar radiation to the solar cell to cause the solar cell to generate an electrical signal. An electrically conductive planar member is positioned in the housing to rest on the housing back wall in supporting relation with the solar cell terminal of opposite polarity. The planar member is operable to dissipate heat radiated by the solar cell as the solar cell generates an electrical signal and further forms a solar cell conductor connected with the solar cell terminal to permit the electrical signal generated by the solar cell to be measured between the planar member and the conductor. 5 figs.

  2. Continuous Flow Microfluidic Bioparticle Concentrator

    PubMed Central

    Martel, Joseph M.; Smith, Kyle C.; Dlamini, Mcolisi; Pletcher, Kendall; Yang, Jennifer; Karabacak, Murat; Haber, Daniel A.; Kapur, Ravi; Toner, Mehmet

    2015-01-01

    Innovative microfluidic technology has enabled massively parallelized and extremely efficient biological and clinical assays. Many biological applications developed and executed with traditional bulk processing techniques have been translated and streamlined through microfluidic processing with the notable exception of sample volume reduction or centrifugation, one of the most widely utilized processes in the biological sciences. We utilize the high-speed phenomenon known as inertial focusing combined with hydraulic resistance controlled multiplexed micro-siphoning allowing for the continuous concentration of suspended cells into pre-determined volumes up to more than 400 times smaller than the input with a yield routinely above 95% at a throughput of 240 ml/hour. Highlighted applications are presented for how the technology can be successfully used for live animal imaging studies, in a system to increase the efficient use of small clinical samples, and finally, as a means of macro-to-micro interfacing allowing large samples to be directly coupled to a variety of powerful microfluidic technologies. PMID:26061253

  3. Continuous Flow Microfluidic Bioparticle Concentrator

    NASA Astrophysics Data System (ADS)

    Martel, Joseph M.; Smith, Kyle C.; Dlamini, Mcolisi; Pletcher, Kendall; Yang, Jennifer; Karabacak, Murat; Haber, Daniel A.; Kapur, Ravi; Toner, Mehmet

    2015-06-01

    Innovative microfluidic technology has enabled massively parallelized and extremely efficient biological and clinical assays. Many biological applications developed and executed with traditional bulk processing techniques have been translated and streamlined through microfluidic processing with the notable exception of sample volume reduction or centrifugation, one of the most widely utilized processes in the biological sciences. We utilize the high-speed phenomenon known as inertial focusing combined with hydraulic resistance controlled multiplexed micro-siphoning allowing for the continuous concentration of suspended cells into pre-determined volumes up to more than 400 times smaller than the input with a yield routinely above 95% at a throughput of 240 ml/hour. Highlighted applications are presented for how the technology can be successfully used for live animal imaging studies, in a system to increase the efficient use of small clinical samples, and finally, as a means of macro-to-micro interfacing allowing large samples to be directly coupled to a variety of powerful microfluidic technologies.

  4. Hydrothermal alteration of organic matter in uranium ores, Elliot Lake, Canada: Implications for selected organic-rich deposits

    SciTech Connect

    Mossman, D.J.; Nagy, B.; Davis, D.W.

    1993-07-01

    Organic matter in the uraniferous Matinenda Formation, Elliot Lake, is preserved in the forms of syngenetic kerogen and solid bitumen as it is in many of the Oklo uranium deposits and in the Witwatersrand gold-uranium ores. The Elliot Lake kerogen is a vitrinite-like material considered to be remnants of the Precambrian cyanobacterial mats. The kerogen at Elliot Lake has reflectances (in oil) ranging from 2.63-7.31% RO{sub max}, high aromaticity, relatively low (0.41-0.60) atomic H/C ratios, and it contains cryptocrystalline graphite. Bitumen, present primarily as dispersed globules (up to 0.5 mm dia.), has reflectances from 0.72-1.32% RO{sub max}, atomic H/C ratios of 0.71-0.81, and is somewhat less aromatic than the kerogen. Overall similarity in molecular compositions indicates that liquid bitumen was derived from kerogen by processes similar to hydrous pyrolysis. The carbon isotopic composition of kerogen ({minus}15.62 to {minus}24.72%), and the now solid bitumen ({minus}25.91 to {minus}33.00%) are compatible with these processes. Despite having been subjected to several thermal episodes, ca. 2.45 Ga old kerogen of microbiological origin here survived as testimony of the antiquity of life on Earth. U-Pb isotopic data from discrete kerogen grains at Elliot Lake form a scattered array intersecting concordia at 2130 {+-} 100 Ma, correspond to the Nipissing event. U-Pb systems were totally reset by this event. Uranium and lead show subsequently partial mobility, the average of which is indicated by the lower concordia intersect of 550 {+-} 260 Ma. The migrated bitumen contains virtually no uranium and thorium but has a large excess of {sup 206}Pb, which indicates that the once liquid bitumen must have acted as a sink for mobile intermediate decay products of {sup 238}U. Emplacement of the Nipissing diabase may have been responsible for producing the bitumen and, indirectly, for its enrichment in {sup 206}Pb as a result of outgassing of {sup 222}Rn.

  5. Cometary science. The organic-rich surface of comet 67P/Churyumov-Gerasimenko as seen by VIRTIS/Rosetta.

    PubMed

    Capaccioni, F; Coradini, A; Filacchione, G; Erard, S; Arnold, G; Drossart, P; De Sanctis, M C; Bockelee-Morvan, D; Capria, M T; Tosi, F; Leyrat, C; Schmitt, B; Quirico, E; Cerroni, P; Mennella, V; Raponi, A; Ciarniello, M; McCord, T; Moroz, L; Palomba, E; Ammannito, E; Barucci, M A; Bellucci, G; Benkhoff, J; Bibring, J P; Blanco, A; Blecka, M; Carlson, R; Carsenty, U; Colangeli, L; Combes, M; Combi, M; Crovisier, J; Encrenaz, T; Federico, C; Fink, U; Fonti, S; Ip, W H; Irwin, P; Jaumann, R; Kuehrt, E; Langevin, Y; Magni, G; Mottola, S; Orofino, V; Palumbo, P; Piccioni, G; Schade, U; Taylor, F; Tiphene, D; Tozzi, G P; Beck, P; Biver, N; Bonal, L; Combe, J-Ph; Despan, D; Flamini, E; Fornasier, S; Frigeri, A; Grassi, D; Gudipati, M; Longobardo, A; Markus, K; Merlin, F; Orosei, R; Rinaldi, G; Stephan, K; Cartacci, M; Cicchetti, A; Giuppi, S; Hello, Y; Henry, F; Jacquinod, S; Noschese, R; Peter, G; Politi, R; Reess, J M; Semery, A

    2015-01-23

    The VIRTIS (Visible, Infrared and Thermal Imaging Spectrometer) instrument on board the Rosetta spacecraft has provided evidence of carbon-bearing compounds on the nucleus of the comet 67P/Churyumov-Gerasimenko. The very low reflectance of the nucleus (normal albedo of 0.060 ± 0.003 at 0.55 micrometers), the spectral slopes in visible and infrared ranges (5 to 25 and 1.5 to 5% kÅ(-1)), and the broad absorption feature in the 2.9-to-3.6-micrometer range present across the entire illuminated surface are compatible with opaque minerals associated with nonvolatile organic macromolecular materials: a complex mixture of various types of carbon-hydrogen and/or oxygen-hydrogen chemical groups, with little contribution of nitrogen-hydrogen groups. In active areas, the changes in spectral slope and absorption feature width may suggest small amounts of water-ice. However, no ice-rich patches are observed, indicating a generally dehydrated nature for the surface currently illuminated by the Sun.

  6. Visco-plastic properties of organic-rich shale gas reservoir rocks and its implication for stress variations within reservoirs

    NASA Astrophysics Data System (ADS)

    Sone, H.; Zoback, M. D.

    2011-12-01

    We are studying the time-dependent deformational properties of shale gas reservoir rocks through laboratory creep experiments in a triaxial deformation apparatus under room temperature and room humidity conditions. Samples come from the Barnett shale (TX), Eagle Ford shale (TX), Haynesville shale (LA), and Fort St. John shale (Canada). The clay and carbonate content of these shales vary markedly, as well as the total organic content. To cover effective pressures both below and above in-situ conditions, confining pressures were between 10-60 MPa. In order to examine creep processes unrelated to pre-failure crack growth, differential stresses during creep were kept below 50% of the ultimate rock strength. Time dependent creep at constant differential stress increases with clay content (regardless of the carbonate content) and there is a pronounced increase in amount of creep at around 35-40% clay content. The amount of creep strain is relatively insensitive to both the confining pressure and differential pressure. More creep occurs in the bedding-perpendicular direction than the bedding-parallel direction, which correlates with the sample's elastic anisotropy. The constitutive law governing the time-dependent deformation of these rocks is visco-plastic, and creep strain is well-approximated by a power-law function of time within the time scales of the experiment (maximum of 2 weeks). Also an oven-dried sample exhibited much less creep, which suggests that the physical mechanism of the creep is likely a hydrolytically-assisted plastic deformation process. Interpretation of the results through visco-elastic theory shows that the power law exponents of these rocks, which reflects how rapid a rock creeps or relaxes stress, vary between 0.01-0.07. Based on these numbers, we can roughly calculate the visco-elastic accumulation of differential stresses within these reservoirs, by assuming a constant intraplate tectonic strain rate (10^-19 - 10^-17) and by considering the ages of these rocks (100-350 Ma). Results suggest that the current intra-reservoir contrast of differential stresses can become as high as tens of MPa. Such prediction is consistent with the occurence of drilling-induced tensile fractures (DITFs) observed in a vertical well from Barnett shale where DITFs appear and disappear corresponding to the intra-reservoir lithological variation. It is important to characterize such stress variations within a reservoir since production from shale gas reservoirs heavily relies on reservoir stimulation by hydraulic fracturing and in-situ stress is a major control on the outcomes of such operations.

  7. Extremely organic-rich coma of comet C/2010 G2 (Hill) during its outburst in 2012

    SciTech Connect

    Kawakita, Hideyo; Kobayashi, Hitomi; Russo, Neil Dello; Vervack, Ron Jr.; Weaver, Harold A.; DiSanti, Mike A.; Opitom, Cyrielle; Jehin, Emmanuel; Manfroid, Jean; Gillon, Michael; Cochran, Anita L.; Harris, Walter M.; Bockelée-Morvan, Dominique; Biver, Nicolas; Crovisier, Jacques; McKay, Adam J.

    2014-06-20

    We performed high-dispersion near-infrared spectroscopic observations of comet C/2010 G2 (Hill) at 2.5 AU from the Sun using NIRSPEC (R ≈ 25,000) at the Keck II Telescope on UT 2012 January 9 and 10, about a week after an outburst had occurred. Over the two nights of our observations, prominent emission lines of CH{sub 4} and C{sub 2}H{sub 6}, along with weaker emission lines of H{sub 2}O, HCN, CH{sub 3}OH, and CO were detected. The gas production rate of CO was comparable to that of H{sub 2}O during the outburst. The mixing ratios of CO, HCN, CH{sub 4}, C{sub 2}H{sub 6}, and CH{sub 3}OH with respect to H{sub 2}O were higher than those for normal comets by a factor of five or more. The enrichment of CO and CH{sub 4} in comet Hill suggests that the sublimation of these hypervolatiles sustained the outburst of the comet. Some fraction of water in the inner coma might exist as icy grains that were likely ejected from nucleus by the sublimation of hypervolatiles. Mixing ratios of volatiles in comet Hill are indicative of the interstellar heritage without significant alteration in the solar nebula.

  8. Organic-rich mud on the western margin of southern Africa: Nutrient source to the Southern Ocean?

    NASA Astrophysics Data System (ADS)

    Compton, John; Herbert, Caren; Schneider, Ralph

    2009-12-01

    The biological pump plays a major role in the transfer of CO2 from the atmosphere to the deep Southern Ocean, a transfer which is largely controlled by the supply of iron and which may partially explain glacial to interglacial variations in pCO2. Analogous to the well-documented, smaller-scale "island mass effect," we propose that the lateral advection of iron by south flowing intermediate waters along the southern African margin may sustain high-productivity blooms of the Subtropical Convergence Zone (SCZ) between 10 and 70°E. We assess the present-day interglacial (Holocene) reservoirs and fluxes of organic carbon (OC) and terrigenous mud on the western margin of southern Africa in order to estimate the potential supply of Fe to the Southern Ocean. The highly productive Benguela Upwelling System (BUS) appears to be a relatively inefficient coastal biological pump. Repeated sediment resuspension by wave and tidal energy dissipation limits OC burial to <0.2% of net primary production (NPP) in the southern BUS and to between 0.2 to 2.4% in the northern BUS. Productivity and OC-rich mud accumulation are focused on the inner portion of the 100-200 km wide shelf which, combined with south flowing bottom currents, limits the export of OC beyond the shelf break to 1.2-8.4% of NPP. However, winnowing of 1 million tons yr-1 of clay particles and the potential early diagenetic benthic (dissolved) Fe flux may supply 10 times more Fe than is transported by dust to the open ocean biological pump of the SCZ. Lowering sea level during glacial periods disperses interglacial mud deposits off the shelf and increases particulate Fe export by as much as a factor of 4. Glacial pulses of margin export may enhance the efficiency of the subantarctic Southern Ocean biological pump and contribute to the initial as well as glacial maximum drawdown in pCO2.

  9. Biogeochemical cycling in an organic-rich coastal marine basin. 7. Sulfur mass balance, oxygen uptake and sulfide retention

    USGS Publications Warehouse

    Chanton, J.P.; Martens, C.S.; Goldhaber, M.B.

    1987-01-01

    Sulfur and oxygen fluxes were quantified in the seasonally varying anoxic marine sedimentary system of Cape Lookout Bight, N.C., U.S.A. Over the three year study period, 1981-1983, the mean annual sulfate reduction rate was determined to be 18.2 ?? 1.6 moles ?? m-2 ?? y-1. This value, added to the estimate of the detrital sulfur input of 1.2 ?? 4.4 gave a total sulfur input of 19.4 ?? 4.7 moles ?? m-2 ?? y-1. The sulfide flux to the sediment-water interface, measured in anaerobic benthic chambers was 4.6 ?? 0.5 moles ?? m-2 ?? y-1, and represented 37% of the annual oxygen uptake rate of 25.2 ?? 2.8 moles ?? m-2 ?? y-1. The sulfide burial rate, determined to be 15.5 ?? 3.1 moles ?? m-2 ?? y-1, was within 5% of the value predicted by summing the fluxes at the sediment-water interface. The C S weight ratio of sediment below the depth of diagenetic reaction was determined to be 2.75. The sulfide retention rate in these rapidly accumulating sediments (10 cm/yr) was 77 ?? 19%. Comparison of this result with previous studies shows that rapid sediment accumulation and the lack of bioturbation control this unusually high degree of sulfide retention. ?? 1987.

  10. Two-Step Resonance-Enhanced Desorption Laser Mass Spectrometry for In Situ Analysis of Organic-Rich Environments

    NASA Technical Reports Server (NTRS)

    Getty, S. A.; Grubisic, A.; Uckert, K.; Li, X.; Cornish, T.; Cook, J. E.; Brinckerhoff, W. B.

    2016-01-01

    A wide diversity of planetary surfaces in the solar system represent high priority targets for in situ compositional and contextual analysis as part of future missions. The planned mission portfolio will inform our knowledge of the chemistry at play on Mars, icy moons, comets, and primitive asteroids, which can lead to advances in our understanding of the interplay between inorganic and organic building blocks that led to the evolution of habitable environments on Earth and beyond. In many of these environments, the presence of water or aqueously altered mineralogy is an important indicator of habitable environments that are present or may have been present in the past. As a result, the search for complex organic chemistry that may imply the presence of a feedstock, if not an inventory of biosignatures, is naturally aligned with targeted analyses of water-rich surface materials. Here we describe the two-step laser mass spectrometry (L2MS) analytical technique that has seen broad application in the study of organics in meteoritic samples, now demonstrated to be compatible with an in situ investigation with technique improvements to target high priority planetary environments as part of a future scientific payload. An ultraviolet (UV) pulsed laser is used in previous and current embodiments of laser desorption/ionization mass spectrometry (LDMS) to produce ionized species traceable to the mineral and organic composition of a planetary surface sample. L2MS, an advanced technique in laser mass spectrometry, is selective to the aromatic organic fraction of a complex sample, which can provide additional sensitivity and confidence in the detection of specific compound structures. Use of a compact two-step laser mass spectrometer prototype has been previously reported to provide specificity to key aromatic species, such as PAHs, nucleobases, and certain amino acids. Recent improvements in this technique have focused on the interaction between the mineral matrix and the organic analyte. The majority of planetary targets of astrobiological interest are characterized by the presence of water or hydrated mineral phases. Water signatures can indicate a history of available liquid water that may have played an important role in the chemical environment of these planetary surfaces and subsurfaces. The studies we report here investigate the influence of water content on the detectability of organics by L2MS in planetary analog samples.

  11. Methodology of organic-rich shale lithofacies identification and prediction: A case study from Marcellus Shale in the Appalachian basin

    NASA Astrophysics Data System (ADS)

    Wang, Guochang; Carr, Timothy R.

    2012-12-01

    The success of shale gas in North America has attracted increased interest in "unconventional" reservoirs. Two critical factors for shale-gas reservoirs are units amenable to hydrologic fracture stimulation and sufficient natural gas content. The effectiveness of hydrologic fracture stimulation is influenced by rock geomechanical properties, which are related to rock mineralogy. The natural gas content in shale reservoirs has a strong relationship with organic matter, which is measured by total organic carbon (TOC). A 3D shale lithofacies model constructed using mineral composition, rock geomechanical properties and TOC content can be applied to optimize the design of horizontal well trajectories and stimulation strategies. Core analysis data, log data and seismic data were used to build a 3D shale lithofacies from core to well and finally to regional scale. Core, advanced and common logs were utilized as inputs to petrophysical analysis, and various pattern recognition methods, such as discriminant analysis, fuzzy logic, neural network and support vector machine. A limited set of eight derived parameters from common logs were determined as critical inputs for pattern recognition methods. Advanced logs, such as pulsed neutron spectroscopy, are used to determine mineral composition and TOC data improve and confirm the quantitative relationship between conventional logs and lithofacies. Seismic data, interpreted sequence stratigraphy and depositional environments were used as constraints to build deterministic and stochastic 3D lithofacies models and to extrapolate lithofacies from well scale to regional scale.

  12. Summary of Dissolved Concentration Limits

    SciTech Connect

    Yueting Chen

    2001-06-11

    According to the Technical Work Plan titled Technical Work Plan for Waste Form Degradation Process Model Report for SR (CRWMS M&O 2000a), the purpose of this study is to perform abstractions on solubility limits of radioactive elements based on the process-level information and thermodynamic databases provided by Natural Environment Program Operations (NEPO) and Waste Package Operations (WPO). The scope of this analysis is to produce solubility limits as functions, distributions, or constants for all transported radioactive elements identified by the Performance Assessment Operations (PAO) radioisotope screening. Results from an expert elicitation for solubility limits of most radioactive elements were used in the previous Total System Performance Assessments (TSPAs). However, the elicitation conducted in 1993 does not meet the criteria set forth by the U.S. Nuclear Regulatory Commission (NRC) due to lack of documentation and traceability (Kotra et al. 1996, Section 3). Therefore, at the Waste Form Abstraction Workshop held on February 2-4, 1999, at Albuquerque, New Mexico, the Yucca Mountain Site Characterization Project (YMP) decided to develop geochemical models to study solubility for the proposed Monitored Geologic Repository. WPO/NEPO is to develop process-level solubility models, including review and compilation of relevant thermodynamic data. PAO's responsibility is to perform abstractions based on the process models and chemical conditions and to produce solubility distributions or response surfaces applicable to the proposed repository. The results of this analysis and conceptual model will feed the performance assessment for Total System Performance Assessment--Site Recommendation (TSPA-SR) and Total System Performance Assessment--License Application (TSPA-LA), and to the Waste Form Degradation Process Model Report section on concentration limits.

  13. Production of fullerenes using concentrated solar flux

    DOEpatents

    Fields, Clark L.; Pitts, John Roland; King, David E.; Hale, Mary Jane; Bingham, Carl E.; Lewandowski, Allan A.

    2000-01-01

    A method of producing soot containing high amounts of fullerenes comprising: providing a primary concentrator capable of impingement of a concentrated beam of sunlight onto a carbon source to cause vaporization of carbon and subsequent formation of fullerenes, or providing a solar furnace having a primary concentrator with a focal point that concentrates a solar beam of sunlight; providing a reflective secondary concentrator having an entrance aperture and an exit aperture at the focal point of the solar furnace; providing a carbon source at the exit aperture of the secondary concentrator; supplying an inert gas over the carbon source to keep the secondary concentrator free from vaporized carbon; and impinging a concentrated beam of sunlight from the secondary concentrator on the carbon source to vaporize the carbon source into a soot containing high amounts of fullerenes.

  14. Modeling of concentrating solar thermoelectric generators

    NASA Astrophysics Data System (ADS)

    McEnaney, Kenneth; Kraemer, Daniel; Ren, Zhifeng; Chen, Gang

    2011-10-01

    The conversion of solar power into electricity is dominated by non-concentrating photovoltaics and concentrating solar thermal systems. Recently, it has been shown that solar thermoelectric generators (STEGs) are a viable alternative in the non-concentrating regime. This paper addresses the possibility of STEGs being used as the power block in concentrating solar power systems. STEG power blocks have no moving parts, they are scalable, and they eliminate the need for an external traditional thermomechanical generator, such as a steam turbine or Stirling engine. Using existing skutterudite and bismuth telluride materials, concentrating STEGs can have efficiencies exceeding 10% based on a geometric optical concentration ratio of 45.

  15. Concentrating molecules in a simple microchannel.

    PubMed

    Jiang, Hai; Daghighi, Yasaman; Chon, Chan Hee; Li, Dongqing

    2010-07-15

    A simple method is proposed and tested to concentrate sample molecules from a dilute solution in a microchannel by electrokinetic means. The microfluidic chip has a straight microchannel connecting two wells and three electrodes. This method uses electrokinetic trapping and flow control simultaneously to concentrate a charged species of interest. A numerical model of the sample concentration process is presented in this paper. Using a fluorescent dye as the sample molecules, experimental investigation into the concentration process was performed. The 90 times of the concentration increase was achieved in 110 s. The numerical simulations of the concentrating and the subsequent dispensing processes agree well with the experimental results.

  16. POTENTIAL DIMETHYLMERCURY CONCENTRATION IN WATER & ORGANIC CONDENSATE

    SciTech Connect

    MEACHAM, J.E.

    2004-12-28

    This document bounds potential dimethylmercury concentration in water or organic condensate that might form in ventilation systems or cooler tank regions. Dimethylmercury concentrations were extremely low and would be below drinking water standards in the water condensate.

  17. Solar concentrator with a toroidal relay module.

    PubMed

    Lin, Jhe-Syuan; Liang, Chao-Wen

    2015-10-01

    III-V multijunction solar cells require solar concentrators with a high concentration ratio to reduce per watt cost and to increase solar energy transforming efficiency. This paper discusses a novel solar concentrator design that features a high concentration ratio, high transfer efficiency, thin profile design, and a high solar acceptance angle. The optical design of the concentrator utilizes a toroidal relay module, which includes both the off-axis relay lens and field lens design in a single concentric toroidal lens shape. The optical design concept of the concentrator is discussed and the simulation results are shown. The given exemplary design has an aspect ratio of 0.24, a high averaged optical concentration ratio 1230×, a maximum efficiency of 76.8%, and the solar acceptance angle of ±0.9°.

  18. Installation package for concentrating solar collector panels

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The concentrating solar collector panels comprise a complete package array consisting of collector panels using modified Fresnel prismatic lenses for a 10 to 1 concentrating ratio, supporting framework, fluid manifolding and tracking drive system, and unassembled components for field erection.

  19. Light ion concentrations in Jupiter's inner magnetosphere

    NASA Technical Reports Server (NTRS)

    Tokar, R. L.; Gurnett, D. A.; Shaw, R. R.; Bagenal, F.

    1982-01-01

    The light ion distribution in the inner Jovian magnetosphere is investigated using whistler dispersion measurements from the Voyager 1 plasma wave instrument and heavy ion plasma concentrations from the plasma instrument. Two models are developed for the light ion concentration over 14 L shells between L = 5.2 and 6.2, one giving a constant concentration along the field line and the other corresponding to an exponential density distribution. Due to heavy ion concentrations near the equator that are typically an order of magnitude larger than the light ion concentration, results obtained are mainly relevant to the light ion concentration outside of the torus. Light ion concentration near the equator ranges from about 1-10% of the heavy ion concentration, while outside the torus the light ions are the dominant species.

  20. 21 CFR 155.191 - Tomato concentrates.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 2 2011-04-01 2011-04-01 false Tomato concentrates. 155.191 Section 155.191 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... Tomato concentrates. (a) Identity—(1) Definition. Tomato concentrates are the class of foods each...

  1. 10 CFR 30.14 - Exempt concentrations.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 1 2013-01-01 2013-01-01 false Exempt concentrations. 30.14 Section 30.14 Energy NUCLEAR... § 30.14 Exempt concentrations. (a) Except as provided in paragraphs (c) and (d) of this section, any... in concentrations not in excess of those listed in § 30.70. (b) This section shall not be deemed...

  2. 7 CFR 58.921 - Concentration.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 3 2012-01-01 2012-01-01 false Concentration. 58.921 Section 58.921 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards... Procedures § 58.921 Concentration. Concentrating by evaporation shall be accomplished with a minimum...

  3. 10 CFR 30.14 - Exempt concentrations.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 1 2012-01-01 2012-01-01 false Exempt concentrations. 30.14 Section 30.14 Energy NUCLEAR... § 30.14 Exempt concentrations. (a) Except as provided in paragraphs (c) and (d) of this section, any... in concentrations not in excess of those listed in § 30.70. (b) This section shall not be deemed...

  4. 7 CFR 58.921 - Concentration.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 3 2014-01-01 2014-01-01 false Concentration. 58.921 Section 58.921 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards... Procedures § 58.921 Concentration. Concentrating by evaporation shall be accomplished with a minimum...

  5. 10 CFR 30.14 - Exempt concentrations.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 1 2014-01-01 2014-01-01 false Exempt concentrations. 30.14 Section 30.14 Energy NUCLEAR... § 30.14 Exempt concentrations. (a) Except as provided in paragraphs (c) and (d) of this section, any... in concentrations not in excess of those listed in § 30.70. (b) This section shall not be deemed...

  6. 7 CFR 58.921 - Concentration.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 3 2013-01-01 2013-01-01 false Concentration. 58.921 Section 58.921 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards... Procedures § 58.921 Concentration. Concentrating by evaporation shall be accomplished with a minimum...

  7. 10 CFR 30.14 - Exempt concentrations.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 1 2011-01-01 2011-01-01 false Exempt concentrations. 30.14 Section 30.14 Energy NUCLEAR... § 30.14 Exempt concentrations. (a) Except as provided in paragraphs (c) and (d) of this section, any... in concentrations not in excess of those listed in § 30.70. (b) This section shall not be deemed...

  8. 7 CFR 58.921 - Concentration.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 3 2011-01-01 2011-01-01 false Concentration. 58.921 Section 58.921 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards... Procedures § 58.921 Concentration. Concentrating by evaporation shall be accomplished with a minimum...

  9. 7 CFR 58.921 - Concentration.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Concentration. 58.921 Section 58.921 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards... Procedures § 58.921 Concentration. Concentrating by evaporation shall be accomplished with a minimum...

  10. NREL's Concentrated Solar Radiation User Facility

    SciTech Connect

    Lewandowski, A.

    1999-09-01

    Declared a national user facility in 1993, NREL's Concentrated Solar Radiation User Facility (CSR) allows industry, government, and university researchers to examine the effects and applications of as much as 50,000 suns of concentrated solar radiation using a High-Flux Solar Furnace and long-term exposure using an ultraviolet (UV) concentrator.

  11. 21 CFR 131.115 - Concentrated milk.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 2 2013-04-01 2013-04-01 false Concentrated milk. 131.115 Section 131.115 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... Concentrated milk. (a) Description. Concentrated milk is the liquid food obtained by partial removal of water...

  12. 21 CFR 131.115 - Concentrated milk.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 2 2012-04-01 2012-04-01 false Concentrated milk. 131.115 Section 131.115 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... Concentrated milk. (a) Description. Concentrated milk is the liquid food obtained by partial removal of water...

  13. 21 CFR 131.115 - Concentrated milk.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 2 2011-04-01 2011-04-01 false Concentrated milk. 131.115 Section 131.115 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... Concentrated milk. (a) Description. Concentrated milk is the liquid food obtained by partial removal of water...

  14. 21 CFR 131.115 - Concentrated milk.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Concentrated milk. 131.115 Section 131.115 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... Concentrated milk. (a) Description. Concentrated milk is the liquid food obtained by partial removal of water...

  15. 21 CFR 131.115 - Concentrated milk.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 2 2014-04-01 2014-04-01 false Concentrated milk. 131.115 Section 131.115 Food... HUMAN CONSUMPTION MILK AND CREAM Requirements for Specific Standardized Milk and Cream § 131.115 Concentrated milk. (a) Description. Concentrated milk is the liquid food obtained by partial removal of water...

  16. The origin of lunar concentric craters

    NASA Astrophysics Data System (ADS)

    Trang, David; Gillis-Davis, Jeffrey J.; Hawke, B. Ray

    2016-11-01

    Lunar concentric craters are a unique class of impact craters because the interior of the craters contains a concentric ridge, but their formation mechanism is unknown. In order to determine the origin of concentric craters, we examined multiple working hypotheses, which include eight impact-related and endogenic processes. We analyzed data sets that originated from instruments onboard Clementine, Kaguya, and the Lunar Reconnaissance Orbiter to characterize the morphology, spatial distribution, composition, and absolute model ages of 114 concentric craters. Concentric craters contain five key properties: (1) a concentric ridge, (2) anomalously shallow floors, (3) their occurrence is concentrated near mare margins and in mare pond regions (4) the concentric ridge composition is similar to the surrounding area and (5) concentric crater ages are Eratosthenian and older. These five key properties served as constraints for testing impact-related and endogenic mechanisms of formation. We find that most impact-related hypotheses cannot explain the spatial and age distribution of concentric craters. As for endogenic hypotheses, we deduce that igneous intrusions are the likely mechanism that formed concentric craters because of the close relationship between concentric craters and floor-fractured craters and the concentration of both features near mare-highland boundaries and in mare ponds. Furthermore, we observe that floor-fractured craters are common at crater diameters > 15 km, whereas concentric craters are common at crater diameters < 15 km. We suggest that igneous intrusions underneath small craters (<15 km) are likely to form concentric craters, whereas intrusions under large craters (>15 km) produce floor-fractured craters.

  17. Cost analysis of carbon dioxide concentrators

    NASA Technical Reports Server (NTRS)

    Yakut, M. M.

    1972-01-01

    A methodology is developed to predict the relevant contributions of the more intangible cost elements encountered in the development of flight-qualified hardware and is used to predict the costs of three carbon dioxide concentration systems. The cost and performance data from Gemini, Skylab, and other programs are utilized as a basis for establishing the cost estimating relationships. The concentration systems analyzed are the molecular sieves C02 concentrator, the hydrogen-depolarized concentrator, and the regenerable solid desiccant concentrator. Besides the cost estimates for each system, their comparative criteria including relative characteristics, operational differences, and development status are considered.

  18. Urine concentrating and diluting ability during aging.

    PubMed

    Sands, Jeff M

    2012-12-01

    Urine concentrating ability is reduced during normal aging in people and rats. The abundance of many of the key transport proteins that contribute to urine concentrating ability is reduced in the kidney medulla of aged rats. The reductions in water, sodium, and urea transport protein abundances, and their reduced response to water restriction, contribute to the reduced ability of aged rats to concentrate their urine and conserve water. If similar mechanisms occur in human kidneys, it would provide a molecular explanation for the reduced urine concentrating ability in aging and may provide opportunities for novel therapeutic approaches to improve urine concentrating ability and/or nocturnal polyuria.

  19. Photovoltaic applications of Compound Parabolic Concentrator (CPC)

    NASA Technical Reports Server (NTRS)

    Winston, R.

    1975-01-01

    The use of a compound parabolic concentrator as field collector, in conjunction with a primary focusing concentrator for photovoltaic applications is studied. The primary focusing concentrator can be a parabolic reflector, an array of Fresnel mirrors, a Fresnel lens or some other lens. Silicon solar cell grid structures are proposed that increase efficiency with concentration up to 10 suns. A ray tracing program has been developed to determine energy distribution at the exit of a compound parabolic concentrator. Projected total cost of a CPC/solar cell system will be between 4 and 5 times lower than for flat plate silicon cell arrays.

  20. Dense-array concentrator photovoltaic system using non-imaging dish concentrator and crossed compound parabolic concentrator

    NASA Astrophysics Data System (ADS)

    Chong, Kok-Keong; Yew, Tiong-Keat; Wong, Chee-Woon; Tan, Ming-Hui; Tan, Woei-Chong; Lai, An-Chow; Lim, Boon-Han; Lau, Sing-Liong; Rahman, Faidz Abdul

    2015-04-01

    Solar concentrating device plays an important role by making use of optical technology in the design, which can be either reflector or lens to deliver high flux of sunlight onto the Concentrator Photovoltaic (CPV) module receiver ranging from hundreds to thousand suns. To be more competitive compared with fossil fuel, the current CPV systems using Fresnel lens and Parabolic dish as solar concentrator that are widely deployed in United States, Australia and Europe are facing great challenge to produce uniformly focused sunlight on the solar cells as to reduce the cost of electrical power generation. The concept of non-imaging optics is not new, but it has not fully explored by the researchers over the world especially in solving the problem of high concentration solar energy, which application is only limited to be a secondary focusing device or low concentration device using Compound Parabolic Concentrator. With the current advancement in the computer processing power, we has successfully invented the non-imaging dish concentrator (NIDC) using numerical simulation method to replace the current parabolic dish as primary focusing device with high solar concentration ratio (more than 400 suns) and large collective area (from 25 to 125 m2). In this paper, we disclose our research and development on dense array CPV system based on non-imaging optics. The geometry of the NIDC is determined using a special computational method. In addition, an array of secondary concentrators, namely crossed compound parabolic concentrators, is also proposed to further focus the concentrated sunlight by the NIDC onto active area of solar cells of the concentrator photovoltaic receiver. The invention maximizes the absorption of concentrated sunlight for the electric power generation system.

  1. Solar concentrators for space processing applications

    NASA Technical Reports Server (NTRS)

    Mcdermit, J. H.; Ruff, R. C.

    1975-01-01

    A study on the technological feasibility of using solar concentrators for crystal growth and zone refining in space has been performed. Previous studies related to the many aspects of the problem are reviewed. It was concluded from this effort that the technology for fabricating, orbiting, and deploying large solar concentrators has been developed. It was also concluded that the technological feasibility of space processing materials in the focal region of a solar concentrator depends primarily on two factors: (1) the ability of a solar concentrator to provide sufficient thermal energy for the process and (2) the ability of a solar concentrator to provide a thermal environment that is conducive to the processes of interest. The study indicates that solar concentrators of reasonable dimensions can satisfactorily provide both of these factors. This study also indicates that solar concentrators are attractive for space processing from the viewpoint of system specific power and system flexibility.

  2. Design of an ultrasmall aspect ratio concentrator

    NASA Astrophysics Data System (ADS)

    Cheng, Ying; Fang, Fengzhou; Zhang, Xiaodong

    2014-11-01

    The concentrated photovoltaic (CPV) can be employed to improve the efficiency of solar cells and reduce the system cost of power generation, which is the primary part of the CPV system. Based on the demands for the concentrators to have an ultrathin and ultralight design, a design of ultrasmall aspect ratio concentrators is proposed. The concentrator is formed by a lens array and a freeform reflector to precisely control the light. The solar cell is placed at the side of the concentrator, which greatly reduces the overall thickness of the concentrator. The design can reduce the aspect ratio of concentrator by a considerable amount. The freeform reflector can shape the light beam and achieve a uniform distribution of light energy.

  3. Optical Evaluation of a Refractive Secondary Concentrator

    NASA Technical Reports Server (NTRS)

    Jaworske, Donald A.; Wong, Wayne A.; Skowronski, Timothy J.

    1999-01-01

    Refractive secondary concentrators are being considered for solar thermal applications because of their ability to archive maximum efficiency through the use of total internal reflection for the concentration and distribution of solar energy. A prototype refractive secondary concentrator was built based on ray tracing analysis to demonstrate this collection and distribution concept. The design included a conical secondary concentrator and a faceted extractor. The objective of this effort was to functionally evaluate the performance of the refractive secondary concentrator/extractor prototype and to compare the results with modeling. Most of the light was found to exit the refractive secondary concentrator through the extractor. In addition, the degree of attenuation encountered by the light as it passed through the refractive secondary concentrator was of interest. Quantifying optical output and validating the modeling will provide further understanding of the efficiency of the prototype and will provide insight for additional design and materials selection activities.

  4. Informing Selection of Nanomaterial Concentrations for ...

    EPA Pesticide Factsheets

    Little justification is generally provided for selection of in vitro assay testing concentrations for engineered nanomaterials (ENMs). Selection of concentration levels for hazard evaluation based on real-world exposure scenarios is desirable. We reviewed published ENM concentrations measured in air in manufacturing and R&D labs to identify input levels for estimating ENM mass retained in the human lung using the Multiple-Path Particle Dosimetry (MPPD) model. Model input parameters were individually varied to estimate alveolar mass retained for different particle sizes (5-1000 nm), aerosol concentrations (0.1, 1 mg/m3), aspect ratios (2, 4, 10, 167), and exposure durations (24 hours and a working lifetime). The calculated lung surface concentrations were then converted to in vitro solution concentrations. Modeled alveolar mass retained after 24 hours is most affected by activity level and aerosol concentration. Alveolar retention for Ag and TiO2 nanoparticles and CNTs for a working lifetime (45 years) exposure duration is similar to high-end concentrations (~ 30-400 μg/mL) typical of in vitro testing reported in the literature. Analyses performed are generally applicable to provide ENM testing concentrations for in vitro hazard screening studies though further research is needed to improve the approach. Understanding the relationship between potential real-world exposures and in vitro test concentrations will facilitate interpretation of toxicological results

  5. Serum copper concentrations in hospitalized newborns.

    PubMed

    González-Tarancón, Ricardo; Calvo-Ruata, Luisa; Aramendía, Maite; Ortega, Carmen; García-González, Elena; Rello, Luis

    2017-01-01

    Low serum Cu and ceruloplasmin (Cp) concentrations in newborns can be the first indication of a severe Cu deficient intake or, alternatively, of genetic diseases affecting Cu metabolism. However, Cu and Cp concentrations can also be influenced by other variables that render their quantitative results difficult to interpret. Therefore, it is necessary to identify these variables and stratify Cu and Cp concentrations according to these altering factors. Serum Cu and Cp concentrations for 564 hospitalized newborns (0-12days of life) are stratified according to their age, prematurity (birth weight or gestational age), type of feeding and inflammatory state (assessed by the serum high sensitivity C-reactive protein (hs-CRP) level) to identify potential correlations. Serum Cu and Cp concentrations are influenced by all four variables analyzed, although inflammation is the most significant: the greater the hs-CRP concentration, the greater the serum Cu and Cp concentrations. Prematurity is also an important factor and preterm infants often show very low Cu and Cp concentrations. Age of life and type of feeding have in turn a more modest effect on these magnitudes, being slightly greater at 3-5days of age in breastfed newborns. Inflammation and prematurity are the main variables affecting serum Cu and Cp concentrations in newborns. Therefore, hs-CRP should always be assayed in parallel to Cu status. When there is an inflammatory state proper interpretation of these concentrations can be challenging. Copyright © 2016 Elsevier GmbH. All rights reserved.

  6. Combinational concentration gradient confinement through stagnation flow.

    PubMed

    Alicia, Toh G G; Yang, Chun; Wang, Zhiping; Nguyen, Nam-Trung

    2016-01-21

    Concentration gradient generation in microfluidics is typically constrained by two conflicting mass transport requirements: short characteristic times (τ) for precise temporal control of concentration gradients but at the expense of high flow rates and hence, high flow shear stresses (σ). To decouple the limitations from these parameters, here we propose the use of stagnation flows to confine concentration gradients within large velocity gradients that surround the stagnation point. We developed a modified cross-slot (MCS) device capable of feeding binary and combinational concentration sources in stagnation flows. We show that across the velocity well, source-sink pairs can form permanent concentration gradients. As source-sink concentration pairs are continuously supplied to the MCS, a permanently stable concentration gradient can be generated. Tuning the flow rates directly controls the velocity gradients, and hence the stagnation point location, allowing the confined concentration gradient to be focused. In addition, the flow rate ratio within the MCS rapidly controls (τ ∼ 50 ms) the location of the stagnation point and the confined combinational concentration gradients at low flow shear (0.2 Pa < σ < 2.9 Pa). The MCS device described in this study establishes the method for using stagnation flows to rapidly generate and position low shear combinational concentration gradients for shear sensitive biological assays.

  7. A network property necessary for concentration robustness

    NASA Astrophysics Data System (ADS)

    Eloundou-Mbebi, Jeanne M. O.; Küken, Anika; Omranian, Nooshin; Kleessen, Sabrina; Neigenfind, Jost; Basler, Georg; Nikoloski, Zoran

    2016-10-01

    Maintenance of functionality of complex cellular networks and entire organisms exposed to environmental perturbations often depends on concentration robustness of the underlying components. Yet, the reasons and consequences of concentration robustness in large-scale cellular networks remain largely unknown. Here, we derive a necessary condition for concentration robustness based only on the structure of networks endowed with mass action kinetics. The structural condition can be used to design targeted experiments to study concentration robustness. We show that metabolites satisfying the necessary condition are present in metabolic networks from diverse species, suggesting prevalence of this property across kingdoms of life. We also demonstrate that our predictions about concentration robustness of energy-related metabolites are in line with experimental evidence from Escherichia coli. The necessary condition is applicable to mass action biological systems of arbitrary size, and will enable understanding the implications of concentration robustness in genetic engineering strategies and medical applications.

  8. Factors Affecting Tocopherol Concentrations in Soybean Seeds.

    PubMed

    Carrera, Constanza S; Seguin, Philippe

    2016-12-21

    Soybean seeds contain several health-beneficial compounds, including tocopherols, which are used by the nutraceutical and functional food industries. Soybean tocopherol concentrations are, however, highly variable. Large differences observed in tocopherol concentrations among soybean genotypes together with the relatively simple biosynthetic pathway involving few genes support the feasibility of selecting for high-tocopherol soybean. Tocopherol concentrations are also highly influenced by environmental factors and field management. Temperature during seed filling and soil moisture appear to be the main factors affecting tocopherol concentrations; other factors such as soil fertility and solar radiation also affect concentrations and composition. Field management decisions including seeding date, row spacing, irrigation, and fertilization also affect tocopherols. Knowledge of factors affecting soybean tocopherols is essential to develop management strategies that will lead to the production of seeds with consistent target concentrations that will meet the needs of the nutraceutical and functional food industries.

  9. A network property necessary for concentration robustness

    PubMed Central

    Eloundou-Mbebi, Jeanne M. O.; Küken, Anika; Omranian, Nooshin; Kleessen, Sabrina; Neigenfind, Jost; Basler, Georg; Nikoloski, Zoran

    2016-01-01

    Maintenance of functionality of complex cellular networks and entire organisms exposed to environmental perturbations often depends on concentration robustness of the underlying components. Yet, the reasons and consequences of concentration robustness in large-scale cellular networks remain largely unknown. Here, we derive a necessary condition for concentration robustness based only on the structure of networks endowed with mass action kinetics. The structural condition can be used to design targeted experiments to study concentration robustness. We show that metabolites satisfying the necessary condition are present in metabolic networks from diverse species, suggesting prevalence of this property across kingdoms of life. We also demonstrate that our predictions about concentration robustness of energy-related metabolites are in line with experimental evidence from Escherichia coli. The necessary condition is applicable to mass action biological systems of arbitrary size, and will enable understanding the implications of concentration robustness in genetic engineering strategies and medical applications. PMID:27759015

  10. Factors affecting atmospheric radon concentration, human health.

    PubMed

    Tchorz-Trzeciakiewicz, D E; Kłos, M

    2017-04-15

    We studied the influence of terrain, geology and weather condition on radon concentration in the atmosphere and occurrence of radon density currents. The survey was carried out in Kowary (SW Poland) and in the spoil tip formed during uranium mining. The measurements of radon concentration were performed using SSNTD LR-115. The measurements of uranium thorium and potassium content in soil were carried out using gamma ray spectrometer Exploranium RS-230. We noticed that terrain and stability of weather condition had significant impact on atmospheric radon concentration. The seasonal variations of radon concentrations in Kowary differ from those usually registered in temperate climate. Based on our analyses, the increase of radon concentration in winter and spring was caused by inversion occurring in that area during these seasons. The observed seasonal variations of radon concentrations in the spoil tip were consistent with those characteristic for temperate climate (the highest radon concentration registered in spring and summer and the lowest in winter and autumn). The spoil tip is located above 900m a.s.l. and is not cover by grass or trees. These circumstances promoted radon exhalation. The air movement above the spoil tip area is intensive, even in winter time. The average atmospheric radon concentration in the spoil tip was 318Bqm(-3). The performed research did not reveal occurrence of radon density currents and flow of radon from the spoil tip to lower lying areas in Kowary. We noticed interdependence of atmospheric radon concentration measured at the height of 1.5 above the ground and uranium content in soil and no correlation between thorium content and radon concentration. The lung cancer in residents of Kowary which is more common than in Poland can be associated with increased concentrations of radon. The average radon concentration in the atmosphere in Kowary was 79Bq m(-3).

  11. Plasma concentrations of voriconazole in falcons.

    PubMed

    Schmidt, V; Demiraj, F; Di Somma, A; Bailey, T; Ungemach, F R; Krautwald-Junghanns, M-E

    2007-08-25

    Doses of 12.5 mg voriconazole/kg bodyweight administered every 12 hours by crop gavage to six falcons for 14 days provided peak plasma concentrations of more than 1 microg/ml, but the trough concentrations were lower and sometimes undetectable. Administering the same doses incorporated into meat that was fed to one falcon for seven days and to three falcons for up to 91 days provided similar plasma concentrations.

  12. Blood Thiamin Concentrations in Bovine Polioencephalomalacia

    PubMed Central

    Loew, F. M.; Dunlop, R. H.

    1972-01-01

    Thiamin concentrations were determined by the thiochrome method in blood from 16 cattle with polioencephalomalacia (PEM) or other apparent central nervous disorders. The mean blood total thiamin concentration of the five cattle with PEM (20.5 ± 5.1 µg/100 ml blood) was not significantly different from concentrations in the cattle with the other disorders, despite evidence of a thiamin diphosphate deficiency reported in cattle with PEM. PMID:4263913

  13. Metal concentrations of tadpoles in experimental ponds

    USGS Publications Warehouse

    Sparling, D.W.; Lowe, T.P.

    1996-01-01

    Anuran tadpoles are found in a variety of habitats, many of which are acidified or have high ambient concentrations of metals from anthropogenic sources. A few studies that have been conducted on metals in tadpoles demonstrate that they can contain high concentrations of some metals but have not demonstrated clear relationships between ambient conditions and metal concentrations. This study examines the influence of soil, water treatment, amphibian species, and body portion analyzed on metal concentration in tadpoles. In northern cricket frogs, gray treefrogs, and green frogs, concentrations of Al and Fe exceeded I0000 g.g-1 and Mg and Mn exceeded 1000 g g-1. Body concentrations of Ba, Be, Fe, Mg, Mn, Ni, Pb, and Sr increased with soil concentrations. Acidification reduced body concentrations of Be and Sr, and pH correlated with Be, Mg, and Sr. Gray treefrogs had significantly lower concentrations of most metals compared to northern cricket frogs, possibly because of differences in microhabitats and soil ingestion. More than half of most metals was sequestered in the gut coil of green frog tadpoles, probably mixed with soil. Depending on bio-availability, many of the metals in gut coils and whole bodies of these tadpoles could be potentially toxic to predators.

  14. Electrets to measure ion concentration in air.

    PubMed

    Kotrappa, P

    2005-08-01

    Positive and negative ions are produced in air, mainly due to radon and terrestrial/cosmic radiation sources. Measuring ion concentration in air indirectly provides a measure of these sources. Electrets (electrically charged pieces of Teflon), when exposed in the environment, collect ions of opposite sign leading to a measurable decrease in charge, depending upon the exposure time and ion concentration. This work describes a method of correlating electret discharge rate to the ion concentration as measured by a calibrated ion density meter. Once calibrated, electrets can then be used to measure ion concentration of either sign. The ion concentration in ambient air was measured to be about 200 ions mL(-1), measured over several hours. Both positive and negative ion concentrations were similar. In a typical room, negative ion concentration was about 3,500 ions mL(-1), and, surprisingly, there were no positive ions at all in that room. Being an integrating passive device, the method provides the unique possibility of measuring low or high concentrations of positive or negative ions over extended periods, which is difficult to do with other ion concentration measuring instruments.

  15. Metamaterial electromagnetic concentrators with arbitrary geometries.

    PubMed

    Yang, Jingjing; Huang, Ming; Yang, Chengfu; Xiao, Zhe; Peng, Jinhui

    2009-10-26

    The electromagnetic concentrators play an important role in the harnessing of light in solar cells or similar devices, where high field intensities are required. The material parameters for two-dimensional (2D) metamaterial-assisted electromagnetic concentrators with arbitrary geometries are derived based on transformation-optical approach. Enhancements in field intensities of the 2D concentrator have been shown by full-wave simulation. All theoretical and numerical results validate the material parameters for the 2D concentrator with irregular cross section we developed.

  16. Prescribing dialysate bicarbonate concentrations for hemodialysis patients.

    PubMed

    Heineken, F G; Brady-Smith, M; Haynie, J; Van Stone, J C

    1988-01-01

    A rearranged equation of Sargent and Gotch (1) was used to determine dialysate bicarbonate concentrations for hemodialysis patients. Parameters in this equation include an estimate of the acid generated by each patient between treatments, an estimate for the dialyzer dialysance for bicarbonate, ultrafiltration rate, blood flow rate and a targeted mid-dialysis plasma bicarbonate concentration of 25 mEq/L. Nine patients were studied over a 35 week period to verify this method of determining each patient's dialysate bicarbonate concentration. Prescribed dialysate bicarbonate concentrations for the nine patients varied from 29 to 38 mEq/L with five patients having a prescribed value of 35 mEq/L. After a baseline period of five weeks, five patients switched from a 37 mEq/L acetate dialysate to their prescribed dialysate bicarbonate concentration. Four patients who had already been on bicarbonate dialysis at a concentration of 35 mEq/L were dialyzed with their prescribed dialysate bicarbonate concentrations. Patients were then followed for a study period of 30 weeks. The prescribed dialysate bicarbonate concentration resulted in more normal acid/base chemistries for both groups of patients. The results also demonstrate that chronic hemodialysis patients require individualization of dialysate bicarbonate concentrations.

  17. A UNIVERSAL MODEL FOR HALO CONCENTRATIONS

    SciTech Connect

    Diemer, Benedikt; Kravtsov, Andrey V.

    2015-01-20

    We present a numerical study of dark matter halo concentrations in ΛCDM and self-similar cosmologies. We show that the relation between concentration, c, and peak height, ν, exhibits the smallest deviations from universality if halo masses are defined with respect to the critical density of the universe. These deviations can be explained by the residual dependence of concentration on the local slope of the matter power spectrum, n, which affects both the normalization and shape of the c-ν relation. In particular, there is no well-defined floor in the concentration values. Instead, the minimum concentration depends on redshift: at fixed ν, halos at higher z experience steeper slopes n, and thus have lower minimum concentrations. We show that the concentrations in our simulations can be accurately described by a universal seven-parameter function of only ν and n. This model matches our ΛCDM results to ≲ 5% accuracy up to z = 6, and matches scale-free Ω{sub m} = 1 models to ≲ 15%. The model also reproduces the low concentration values of Earth-mass halos at z ≈ 30, and thus correctly extrapolates over 16 orders of magnitude in halo mass. The predictions of our model differ significantly from all models previously proposed in the literature at high masses and redshifts. Our model is in excellent agreement with recent lensing measurements of cluster concentrations.

  18. Analysis and design of holographic solar concentrators

    NASA Astrophysics Data System (ADS)

    Kostuk, Raymond K.; Rosenberg, Glenn

    2008-08-01

    The diffraction and the dispersion properties of holographic optical elements are examined for use as solar concentrators for photovoltaic and hybrid photovoltaic/thermal energy conversion systems. The diffraction angle and efficiency are computed for folded optical geometries that are potentially useful for low concentration ratio systems that can reduce the cost of residential solar energy systems. An investigation of the collection efficiency of a holographic planar concentrator and a spectrum splitting concentrator are analyzed with different construction parameters. It is found that collection angles of 40o and spectral bandwidth of 70 nm result with folded optical geometries for single volume holograms.

  19. FLOW BEHAVIOUR OF CONCENTRATED ORANGE JUICE.

    PubMed

    Mizrahi, Shimon; Berk, Zeki

    1970-07-01

    Orange concentrate, at the 60-65° Brix concentration level, is a non-Newtonian fluid with yield stress and time dependent behaviour. While recovery from low-rate shear is reversible, shear at high rate causes irreversible destruction of the viscous structure. Part of this effect is due to disintegration of pulp particles. Pulpless concentrate (serum) is also non-Newtonian, but yield stress and time dependent behaviour are present only when pectin concentration is high. Depectinized serum is Newtonian. The effect of temperature on flow properties of all three types of material was studied.

  20. Alignment method for parabolic trough solar concentrators

    DOEpatents

    Diver, Richard B.

    2010-02-23

    A Theoretical Overlay Photographic (TOP) alignment method uses the overlay of a theoretical projected image of a perfectly aligned concentrator on a photographic image of the concentrator to align the mirror facets of a parabolic trough solar concentrator. The alignment method is practical and straightforward, and inherently aligns the mirror facets to the receiver. When integrated with clinometer measurements for which gravity and mechanical drag effects have been accounted for and which are made in a manner and location consistent with the alignment method, all of the mirrors on a common drive can be aligned and optimized for any concentrator orientation.