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Sample records for material provenance clays

  1. Membrane behavior of clay liner materials

    NASA Astrophysics Data System (ADS)

    Kang, Jong Beom

    Membrane behavior represents the ability of porous media to restrict the migration of solutes, leading to the existence of chemico-osmosis, or the flow of liquid in response to a chemical concentration gradient. Membrane behavior is an important consideration with respect to clay soils with small pores and interactive electric diffuse double layers associated with individual particles, such as bentonite. The results of recent studies indicate the existence of membrane behavior in bentonite-based hydraulic barriers used in waste containment applications. Thus, measurement of the existence and magnitude of membrane behavior in such clay soils is becoming increasingly important. Accordingly, this research focused on evaluating the existence and magnitude of membrane behavior for three clay-based materials that typically are considered for use as liners for waste containment applications, such as landfills. The three clay-based liner materials included a commercially available geosynthetic clay liner (GCL) consisting of sodium bentonite sandwiched between two geotextiles, a compacted natural clay known locally as Nelson Farm Clay, and compacted NFC amended with 5% (dry wt.) of a sodium bentonite. The study also included the development and evaluation of a new flexible-wall cell for clay membrane testing that was used subsequently to measure the membrane behaviors of the three clay liner materials. The consolidation behavior of the GCL under isotropic states of stress also was evaluated as a preliminary step in the determination of the membrane behavior of the GCL under different effective consolidation stresses.

  2. Mineralogy and provenance of clays in miarolitic cavities of the Pikes Peak Batholith, Colorado

    USGS Publications Warehouse

    Kile, D.E.

    2005-01-01

    Clay samples from 105 cavities within miarolitic granitic pegmatites throughout the Pikes Peak batholith, in Colorado, were analyzed by powder X-ray diffraction (XRD). Smectite (beidellite), illite, and kaolinite were found within the cavities. Calculation of crystallite-thickness distribution (CTD), mean thickness of the crystallites, and variance in crystallite thickness, as deduced from XRD patterns, allowed a determination of provenance and mode of formation for illite and smectite. Authigenic miarolitic-cavity illite and smectite show lognormal CTDs and larger mean thicknesses of crystallites than do their soil-derived counterparts; non-lognormal illite in a cavity results from mixing of cavity and soil illite. Analysis of mean thickness and thickness variance shows that crystal growth of illite is initiated by a nucleation event of short duration, followed by surface-controlled kinetics. Crystallization of the miarolitic cavity clays is presumed to occur by neoformation from hydrothermal fluids. The assessment of provenance allows a determination of regional and local distributions of clay minerals in miarolitic cavities within the Pikes Peak batholith.

  3. Synthetic organo- and polymer- clays : preparation, characterization, and materials applications.

    SciTech Connect

    Carrado, K. A.; Chemistry

    2000-01-01

    We have over the years developed and patented a general technique for the hydrothermal synthesis of clay minerals in the presence of organic, organometallic, and polymeric intercalants. This review will summarize the details for crystallization of modified hectorites along with their characterization and materials applications. Among the several potential uses of these synthetic materials, there are two important applications concerning catalysis and composites. The fate of the template dictates which of these applications is pertinent. First, if the organic molecule or polymer is used with the intention of acting as templates of pore structure, then the organic template is removed after the modified clay has been crystallized. Upon template removal, the now porous materials are examined for their use as potential catalysts and catalyst supports. We have recently proven a correlation between catalyst pore size in the mesoporous range and the size and concentration of a polymeric template that is used. Preliminary hydrodesulfurization catalytic results have been obtained using these materials. If, on the other hand, intercalants are allowed to remain as a part of the structure, then a distinctive class of organic-inorganic composites becomes possible. When polymeric intercalants are used, especially at high concentrations, the materials have relevance to nanocomposite applications. Work in this area has focused on incorporating polymers at higher than 85 wt.% of the nanocomposite.

  4. Clay mineral contribution from various provenances in the northern South China Sea over the past 400 kyr: implications for the East Asian monsoon evolution

    NASA Astrophysics Data System (ADS)

    Chen, Quan; Liu, Zhifei; Xie, Xin; Kissel, Catherine

    2014-05-01

    Clay mineralogy of Core MD12-3432 taken at 2125 m water depth (CIRCEA cruise on board the R.V. Marion Dufresne, IPEV) in the northern South China Sea was investigated in order to understand the time series contribution of terrigenous sediments from various provenances. With calibration of a low-resolution analysis on carbonate concentration and major elements, we converted the XRF core scanned calcium data into a high-resolution carbonate content records. Through referring to the well-dated carbonate record of nearby Core MD05-2904, we established a reliable age model, indicating about 400 kyr ago at the bottom of Core MD12-3432. The clay mineral assemblage is dominated by smectite (23-59%) and illite (22-43%), with minor chlorite (13-27%) and kaolinite (4-13%). The time series variation of clay mineral assemblages indicates strong glacial-interglacial cyclicity. In general, the variation in smectite content is similar to that of carbonate concentration, with higher values during interglacials than during glacials, while illite and chlorite contents showing opposite patterns. The change in kaolinite content shows an independent pattern with high values during glacials, corresponding well with the illite crystallinity variation. The provenance analysis of these clay minerals suggests three end-member sources: all smectites derive from Luzon, all kaolinites originate from the Pearl River, and illite and chlorite are coming from both the Pearl River and Taiwan. Using the linear separation method of illite crystallinity, a time series of the clay mineral contribution from the three major provenances to the northern South China Sea was reconstructed. Combined with spectral analyses, we suggest the clay mineral contribution from Pearl River was mainly influenced by sea level change, while the East Asian summer monsoon controlled the contribution from Luzon. The strong precipitation rate related to intensive East Asian summer monsoon would have enhanced the denudation and

  5. Clay minerals in surface sediment of the north Yellow Sea and their implication to provenance and transportation

    NASA Astrophysics Data System (ADS)

    Li, Yan; Li, An-Chun; Huang, Peng; Xu, Fang-Jian; Zheng, Xu-Feng

    2014-11-01

    The clay minerals in surface sediments of the north Yellow Sea have been identified with X-ray diffraction analysis and scanning electron microscope and energy dispersive X-ray spectrometer analysis to constrain the provenance and sediment transportation system in the area. Illite, with an average abundance of 58%, is the dominant mineral, followed by smectite (20% on average), chlorite (16% on average) and kaolinite (6% on average). The result of the a K-mean clustering analysis for the clay minerals show a close relationship between sedimentary types and clay mineral assemblages: there is more kaolinite and smectite in the muddy area in the western part of the north Yellow Sea and more chlorite in the sandy area in the eastern part. The Huanghe (Yellow River) is considered to provide most of the clay minerals, and in particular, rich kaolinite and smectite to the muddy area, whereas the Yalujiang provides large amounts of illite and chlorite. The spatial distribution characteristics of the clay minerals are closely related with the local circulation system, including the Shandong Coastal Current and Yellow Sea Warm Current. The former transports the outflow of the Huanghe to the north Yellow Sea, whereas the intrusion of the latter in wintertime is responsible for the annular enrichment of smectite in central part, as well as poor classification near Dalian Bay.

  6. Mechanical Properties of Composite Material Using Coal Ash and Clay

    NASA Astrophysics Data System (ADS)

    Fukumoto, Isao; Kanda, Yasuyuki

    Coal ash is industry waste exhausted lots of amount by electric power plant. The particle sizes of coal ash, especially coal fly ash are very fine, and the chemical component are extremely resemble with Okinawa-Kucha clay. From the point of view that clay is composed of particles of micro meter size in diameter, we should try the application for fabrication of composite material using coal fly ash and clay. The comparison of the mechanical properties of composite material using coal fly ash and clay were performed during electric furnace burning and spark plasma sintering. As a result, the bending strength of composite material containing the coal ash 10% and fired at 1423K using the electric furnace after press forming at 30 MPa showed the highest value of 47 MPa. This phenomenon suggests a reinforcement role of coal ash particles to clay base material. In spark plasma sintering process, the bending strength of the composite material containing the clay 5-10% to fly ash base material fired at 1473K and pressured at 20 MPa showed the highest value of 88 MPa. This result indicates a binder effect of clay according to the liquid phase sintering of melted clay surrounding around coal fly ash particles surface.

  7. Antimicrobial clay-based materials for wound care.

    PubMed

    Gaskell, Elsie E; Hamilton, Ashley R

    2014-04-01

    The historical use of clay minerals for the treatment of wounds and other skin ailments is well documented and continues within numerous human cultures the world over. However, a more scientific inquiry into the chemistry and properties of clay minerals emerged in the 19th century with work investigating their role within health gathering pace since the second half of the 20th century. This review gives an overview of clay minerals and how their properties can be manipulated to facilitate the treatment of infected wounds. Evidence of the antimicrobial and healing effects of some natural clay minerals is presented alongside a range of chemical modifications including metal-ion exchange, the formation of clay-drug composites and the development of various polymer-clay systems. While the evidence for applying these materials to infected wounds is limited, we contextualize and discuss the future of this research.

  8. A quantification model for the structure of clay materials.

    PubMed

    Tang, Liansheng; Sang, Haitao; Chen, Haokun; Sun, Yinlei; Zhang, Longjian

    2016-07-04

    In this paper, the quantification for clay structure is explicitly explained, and the approach and goals of quantification are also discussed. The authors consider that the purpose of the quantification for clay structure is to determine some parameters that can be used to quantitatively characterize the impact of clay structure on the macro-mechanical behaviour. According to the system theory and the law of energy conservation, a quantification model for the structure characteristics of clay materials is established and three quantitative parameters (i.e., deformation structure potential, strength structure potential and comprehensive structure potential) are proposed. And the corresponding tests are conducted. The experimental results show that these quantitative parameters can accurately reflect the influence of clay structure on the deformation behaviour, strength behaviour and the relative magnitude of structural influence on the above two quantitative parameters, respectively. These quantitative parameters have explicit mechanical meanings, and can be used to characterize the structural influences of clay on its mechanical behaviour.

  9. An ion diffusion model in semi-permeable clay materials.

    PubMed

    Liu, Chongxuan

    2007-08-01

    Clay materials typically contain negative surface charges that induce electrostatic fields (or diffuse double layers) in electrolytes. During ion diffusion in a porous medium of clay materials, ions dynamically interact with the electrostatic fields associated with individual clay grains by depressing or expanding the electrostatic double layers, which subsequently affects ionic fluxes. Current theory of ion transport in porous media, however, cannot explicitly account for the dynamic interactions. Here we proposed a model by coupling electrodynamics and nonequilibrium thermodynamics (EDNT) to describe ion diffusion in clay materials as a complex function of factors including clay surface charge density, tortuosity, porosity, chemicoosmotic coefficient, and ion self-diffusivity. The model was validated by comparing the calculated and measured apparent ion diffusion coefficients in clay materials as a function of ionic strength. At transitional states, ion diffusive fluxes are dynamically related to the electrostatic fields, which shrink or expand as ion diffusion occurs. At steady states, the electrostatic fields are time-invariant and ion diffusive fluxes conform to flux and concentration gradient relationships; and apparent diffusivity can be approximated by the ion diffusivity in bulk electrolytes corrected by a tortuosity factor and macroscopic concentration discontinuities at the interfaces between clay materials and bulk solutions.

  10. Effects of Clay Mineral Provenance and Clay Diagenesis on the Hanging Wall of a Megasplay Fault: Results from Riser Drilling, Nankai Trough Seismogenic Zone Experiment

    NASA Astrophysics Data System (ADS)

    Underwood, M.; Song, C.

    2015-12-01

    IODP Expedition 348 set a new record for sampling depth by scientific ocean drilling. Cores were recovered from the Nankai accretionary prism (Site C0002) at depths of 2163-2218 mbsf; cuttings were recovered continuously to 3058 mbsf. Shallower strata near the top of the accretionary prism are as young as 5.6 Ma, but the deeper interval has an apparent depositional age of 9.56-10.73 Ma. The structural context is within the hanging wall of a megasplay fault. Quantitative analyses of the clay mineral assemblages (using X-ray diffraction) show that the most abundant clay mineral is smectite, followed by illite, chlorite, and kaolinite. The mudstones at Site C0002 contain significantly lower percentages of smectite (~40% of clay-size fraction) as compared to coeval Miocene strata at Sites C0011 and C0012 in the nearby subduction inputs of Shikoku Basin (>50% of clay-size fraction). One likely reason for the difference is an overprint of detrital assemblages by smectite-to-illite diagenesis, which results in a steady down-hole increase in illite within the I/S mixed-layer phase. Another possible reason, however, is a spatial shift in depositional environments and detrital provenance. The mud-dominant facies of the accretionary prism is enigmatic (when compared to the frontal prism), and its original depositional setting remains uncertain. The accreted mudstones might have been deposited in a trench during a period in which supplies of sandy sediment were restricted. Northwestward migration of a triple junction that joins the Japan, Izu-Bonin, and Nankai plate boundaries also might have played a role, either by reducing the rate of plate convergence at ~7-12 Ma or by shifting pre-accretion depositional settings from the NE side of the triple junction (subducting Pacific plate) to the SW side (Shikoku Basin, subducting Philippine Sea plate). Regardless of the exact paleogeography, we predict that lower initial percentages of detrital smectite and gradual diagenetic loss

  11. A global renewable mix with proven technologies and common materials

    NASA Astrophysics Data System (ADS)

    Ballabrera, J.; Garcia-Olivares, A.; Garcia-Ladona, E.; Turiel, A.

    2012-04-01

    A global alternative mix to fossil fuels is proposed, based on proven renewable energy technologies that do not use scarce materials. Taking into account the availability of materials, the resulting mix consists of a combination of onshore and offshore wind turbines, concentrating solar power stations, hydroelectricity and wave power devices attached to the offshore turbines. Solar photovoltaic power could contribute to the mix if its dependence on scarce materials is solved. Material requirements are studied for the generation, power transport and for some future transport systems. The order of magnitude of copper, aluminium, neodymium, lithium, nickel, zinc and platinum that might be required for the proposed solution is obtained and compared with available reserves. While the proposed global alternative to fossil fuels seems technically feasible, lithium, nickel and platinum could become limiting materials for future vehicles fleet if no global recycling system were implemented and rechargeable zinc-air batteries could not be developed. As much as 60% of the current copper reserves would have to be employed in the implementation of the proposed solution. Altogether, the availability of materials may become a long-term physical constraint, preventing the continuation of the usual exponential growth of energy consumption.

  12. Provenance of deglacial IRD and clay minerals in the Chukchi Plateau, western Arctic Ocean

    NASA Astrophysics Data System (ADS)

    Park, K. K.; Khim, B. K.; Ohkushi, K.

    2012-04-01

    A gravity core PC01 with a multiple core PL01 was collected from the Chukchi Plateau in the western Arctic Ocean on the R/V Mirai Cruise MR09-03. Core PL01 was compensated for the top-loss of core PC01, which represents a complete composite core. Age of the composite core was estimated by correlation of geochemical properties and IRD abundance with well-dated cores in the western Arctic Ocean, because AMS 14C dates of bulk sediments were contaminated by old carbon. The distinct deglacial interval of the composite core was characterized by high CaCO3 and TOC contents, high C/N ratios, and low δ13C values, which clearly indicates the increased terrestrial contribution. Based on the microscope and SEM observation, the major IRD constituents are composed of carbonate minerals, supporting the high CaCO3 content at the deglacial interval. These deglacial IRDs including carbonate minerals are possibly originated from the Canadian Arctic Archipelago. Clay mineral data at the high IRD interval show high kaolinite/chlorite ratios due to the increase of kaolnite that may be derived from the northern Alaskan margin of the North America. Therefore, the deglacial interval with high IRD abundance and increase of kaolinite/chlorite ratios indicates the intensified Beaufort Gyre system that played an important role in the sediment delivery.

  13. Clay particles as binder for earth buildings materials: a fresh look into rheology of dense clay suspensions

    NASA Astrophysics Data System (ADS)

    Landrou, Gnanli; Brumaud, Coralie; Habert, Guillaume

    2017-06-01

    In the ceramic industry and in many sectors, clay minerals are widely used. In earthen construction technique, clay plays a crucial role in the processing. The purpose of this research is to understand and modify the clay properties in earth material to propose an innovative strategy to develop a castable earth-based material. To do so, we focused on the modification of clay properties at fresh state with inorganic additives. As the rheological behaviour of clays is controlled by their surface charge, the addition of phosphate anion allows discussing deep the rheology of concentrated clay suspensions. We highlighted the thixotropic and shear thickening behaviour of a dispersed kaolinite clay suspensions. Indeed, by adding sodium hexametaphosphate the workability of clay paste increases and the behaviour is stable during time after a certain shear is applied. Moreover, we stress that the aging and the shift in critical strain in clay system are due to the re-arrangement of clay suspension and a decrease of deformation during time. The understanding of both effect: thixotropy and aging are crucial for better processing of clay-based material and for self-compacting clay concrete. Yet, studies need to pursue to better understand the mechanism.

  14. Modification of clay-based waste containment materials

    SciTech Connect

    Adu-Wusu, K.; Whang, J.M.; McDevitt, M.F.

    1997-12-31

    Bentonite clays are used extensively for waste containment barriers to help impede the flow of water in the subsurface because of their low permeability characteristics. However, they do little to prevent diffusion of contaminants, which is the major transport mechanism at low water flows. A more effective way of minimizing contaminant migration in the subsurface is to modify the bentonite clay with highly sorptive materials. Batch sorption studies were conducted to evaluate the sorptive capabilities of organo-clays and humic- and iron-based materials. These materials proved to be effective sorbents for the organic contaminants 1,2,4-trichlorobenzene, nitrobenzene, and aniline in water, humic acid, and methanol solution media. The sorption capacities were several orders of magnitude greater than that of unmodified bentonite clay. Modeling results indicate that with small amounts of these materials used as additives in clay barriers, contaminant flux through walls could be kept very small for 100 years or more. The cost of such levels of additives can be small compared to overall construction costs.

  15. Association of nucleotides with homoionic clays. [catalysis of prebiotic materials

    NASA Technical Reports Server (NTRS)

    Odom, D. G.; Rao, M.; Oro, J.; Lawless, J. G.

    1979-01-01

    The binding of nucleotides to homoionic clays is studied as a possible mechanism for the concentration and catalysis of biological or prebiotic materials on the prebiotic earth. Samples of radioactively labeled adenosine and thymidine nucleotides were mixed in solutions with bentonite, kaolinite or Dowex-50 particles in which all exchangeable sites were occupied by Na, Mg, Ca, Mn, Fe, Cu or Zn ions. The binding of nucleotides to homoionic clays is observed, with adenosine nucleotides favored over thymidine, bentonite as the best absorber, and greater binding to clays homoionic in transition metal ions. Results indicate that the oligomerization of nucleotides may be possible by this mechanism, however difficulties in nucleotide variability and base pairing may arise due to the observed preference for purines at the adsorption sites.

  16. Polymer-clay nanocomposites as precursors of nanostructured carbon materials for electrochemical devices: templating effect of clays.

    PubMed

    Fernández-Saavedra, Rocío; Darder, Margarita; Gómez-Avilés, Almudena; Aranda, Pilar; Ruiz-Hitzky, Eduardo

    2008-04-01

    The present work introduces a comparative study on the use of polymer nanocomposites containing clay minerals of different structure, such as montmorillonite and sepiolite as host solids for the templating synthesis of carbon-like materials from different organic precursors. Carbon-clay nanocomposites were obtained by polymerization of either acrylonitrile or sucrose previously inserted in the pores of the clay minerals, followed by their further thermal transformation in carbon-like compounds. Acid treatment of the resulting carbon-clay nanocomposites removes the inorganic templates giving carbon-like materials with different textural features. Polymer-clay, carbon-clay and carbon-like materials have been characterized by applying spectroscopic techniques as FTIR and in situ EIS (electrochemical impedance spectroscopy) and other structural, textural and analytical tools (chemical analysis, XRD, SEM-EDX, TEM-EDX, N2 adsorption isotherms,...). Electrochemical properties of these carbon-clay nanocomposites, as well as their templated carbonaceous materials and their use as electrode materials of different electrochemical devices such as rechargeable Li-batteries, supercapacitors and electrochemical sensors, are also discussed.

  17. Fate and Tranport of MTBE in Clay-Rich Materials

    NASA Astrophysics Data System (ADS)

    lenczewski, m e

    2001-12-01

    A recent report by the U.S. Geological Survey identified methyl tert-butyl ether (MTBE), a constituent of reformulated gasoline, as the most common contaminant of urban aquifers in the United States. MTBE has been released into groundwater supplies by leaking underground fuel tanks. In Illinois, it has been found in 26 of the 1,800 public water supplies and although detection was intermittent, levels were high enough to be offensive to users in some Illinois communities. MTBE is also being used in Mexico to solve the problem of air quality; however, it has the potential to harm the drinking water quality in the process. Early research on MTBE considered it resistant to biodegradation and unable to adsorb to soils and sediments. However, recent evidence indicates that biodegradation does occur under certain conditions and that sorption can occur to organic materials. This research project will investigate the biodegradation of MTBE and its sorption to the clay-rich glacial till found in northern Illinois and lacustrine clays found in the Chalco Basin, Mexico City, Mexico whose interaction with MTBE has not previously been studied. The principal hypothesis of this research is that the microorganisms and environmental factors in clay-rich materials will increase the biodegradation and sorption of MTBE as compared to sandy materials. The experiments will simulate a spill of MTBE or downgradient from a gasoline spill. Microcosms and batch isotherm experiments will be used to demonstrate the potential for biodegradation and sorption in these materials; however, laboratory results are not considered reliable estimates of actual field sorption and biodegradation rates. Therefore long-term column experiments will also be conducted in which large sample volumes of material that simulate the heterogeneities naturally observed in the environment. This research will increase understanding of the biodegradation and sorption of MTBE and lay the necessary groundwork to implement

  18. Engineered clay-shredded tyre mixtures as barrier materials

    SciTech Connect

    Al-Tabbaa, A.; Aravinthan, T.

    1997-12-31

    An engineered clay consisting of kaolin and bentonite was mixed with shredded tyre in various weight percentages and examined for use as a constituent in a landfill liner. The clay-tyre mixtures properties in terms of compaction, unconfined compressive strength, permeability to water and paraffin, leachability, stress-strain behaviour, free swell behaviour and swelling pressure were investigated. The results show that the dry density and strength reduced with the addition of tyre and also with increased tyre content but that good interaction was developed between the clay and tyre. The strain at failure increased showing reinforcing effect of the tyre. The permeability to paraffin was considerably reduced compared to that to water due to the presence of the tyre which caused high swelling pressures to develop. The leachability results indicate initial high concentrations leaching out of the soil-tyre mixtures which will be subjected to dilution in the environment. This work adds evidence to the potential advantages of using soil-tyre mixtures as a landfill liner material.

  19. Remediation of copper polluted red soils with clay materials.

    PubMed

    Zhang, Gangya; Lin, Yunqing; Wang, Mingkuang

    2011-01-01

    Attapulgite and montmorillonite were utilized to remediate heavy metal polluted red soils in Guixi City, Jiangxi Province, China. The effects of clay minerals on availability, chemical distribution, and biotoxicity of Cu and Zn were evaluated. The results provided a reference for the rational application of clay materials to remediate heavy metal contaminated soils. From the sorption experiment, the maximum adsorbed Cu2+ by attapulgite and montmorillonite was 1501 and 3741 mg/kg, respectively. After polluted red soil was amended with attapulgite or montmorillonite and cultured at 30 and 60 days, soil pH increased significantly compared to the control. An 8% increase in the amount of montmorillonite in soil and 30 days incubation decreased acid exchangeable Cu by 24.7% compared to the control red soil. Acid exchangeable Cu decreased with increasing amounts of attapulgite and montmorillonite, with best remediation effect reached at a dose of 8%. Results also showed that the Cu poisoning effect on earthworms was reduced with the addition of attapulgite and montmorillonite. Montmorillonite showed the best effect, with the addition of a 2% dose the mortality of earthworms decreased from 60% to zero compared to the control. Our results indicated that the bioavailability of Cu in soils was reduced more effectively with the application of montmorillonite than attapulgite.

  20. U-Pb ages of detrital zircon and provenances of Red Clay in the Chinese Loess Plateau

    NASA Astrophysics Data System (ADS)

    Gong, Hujun; Xie, Wenbin; Zhang, Rui; Zhang, Yunxiang

    2017-05-01

    The Chinese Loess Plateau (CLP), which is located in the central part of China, mainly contains two sequences: the Quaternary loess-paleosol sequence and the late Miocene-Pliocene Red Clay sequence. U-Pb ages of detrital zircon from the Quaternary loess-paleosol sequences indicate that the current spatial pattern of central Asian aridification was largely established during the early Quaternary. U-Pb ages of detrital zircon from the underlying Red Clay sequences demonstrate that the northern source regions were important contributors for the dust since the late Miocene, except for the periods of ∼8 Ma and ∼5.5 to ∼4 Ma. These two periods correspond to increased and decreased dust deposition in the North Pacific, respectively, ascribed to the late Miocene aridification of the Qaidam Basin (in the west of the CLP) and the early Pliocene aridification of the Tarim Basin (in the west of the CLP). We attribute the increase of the Qaidam Basin-derived North Pacific dust fluxes to the uplift of the NE Tibetan Plateau. Such uplift also controlled the climatic and environmental changes in central Asian during the late Miocene. This study highlights the dynamical process of the central Asian aridification during the late Miocene-Pliocene.

  1. A novel clay-based catalytic material: Preparation and properties

    SciTech Connect

    Lussier, R.J. )

    1991-05-01

    A novel acid-leached calcined laolin has been prepared by careful control of the calcination and acid leach conditions. A narrow calcination window gives an extremely acid-reactive calcined kaolin, which develops high surface areas at a rate much faster than that of samples calcined outside this range. This more acid active calcined kaolin also allows the use of extremely low levels of acid, which results in most of the alumina being in the solid phase during the entire leach step. Al{sup 27} NMR results indicate that most acid-reactive calcined clay has the lowest level of octahedral and the highest level of five-coordinate Al. Acids containing anions that do not complex with aluminum such as hydrochloric, nitric, or aluminum chloride work in this process, while acids containg anions that complex with aluminum such a sulfuric or phosphoric do not lead to the same high surface area, catalytically active products. Properly calcined and leached materials show a broad distribution of pores centered at about 40 (angstrom).

  2. Fluoride content of clay minerals and argillaceous earth materials

    USGS Publications Warehouse

    Thomas, J.; Glass, H.D.; White, W.A.; Trandel, R.M.

    1977-01-01

    A reliable method, utilizing a fluoride ion-selective electrode, is described for the determination of fluoride in clays and shales. Interference by aluminum and iron is minimal. The reproducibility of the method is about ??5% at different levels of fluoride concentration. Data are presented for various clay minerals and for the <2-??m fractions of marine and nonmarine clays and shales. Fluoride values range from 44 ppm (0.0044%) for nontronite from Colfax, WA, to 51,800 ppm (5.18%) for hectorite from Hector, CA. In general, clays formed under hydrothermal conditions are relatively high in fluoride content, provided the hydrothermal waters are high in fluoride content. Besides hectorite, dickite from Ouray, CO, was found to contain more than 50 times as much fluoride (6700 ppm) as highly crystalline geode kaolinite (125 ppm). The clay stratum immediately overlying a fluorite mineralized zone in southern Illinois was found to have a higher fluoride content than the same stratum in a nonmineralized zone approximately 1 mile away. Nonmarine shales in contact with Australian coals were found to be lower in fluoride content than were marine shales in contact with Illinois coals. It is believed that, in certain instances, peak shifts on DTA curves of similar clay minerals are the result of significant differences in their fluoride content. ?? 1977.

  3. Clay Play

    ERIC Educational Resources Information Center

    Rogers, Liz; Steffan, Dana

    2009-01-01

    This article describes how to use clay as a potential material for young children to explore. As teachers, the authors find that their dialogue about the potential of clay as a learning medium raises many questions: (1) What makes clay so enticing? (2) Why are teachers noticing different play and conversation around the clay table as compared to…

  4. Clay Play

    ERIC Educational Resources Information Center

    Rogers, Liz; Steffan, Dana

    2009-01-01

    This article describes how to use clay as a potential material for young children to explore. As teachers, the authors find that their dialogue about the potential of clay as a learning medium raises many questions: (1) What makes clay so enticing? (2) Why are teachers noticing different play and conversation around the clay table as compared to…

  5. Polyimide-Clay Composite Materials for Space Application

    NASA Technical Reports Server (NTRS)

    Orwoll, Robert A.; Connell, John W. (Technical Monitor)

    2005-01-01

    The introduction of nanometer-sized clay particles into a polyimide matrix has been shown to enhance the physical properties of specific polymer systems. The clay comprises large stacked platelets of the oxides of aluminum and silicon. These sheets have long dimensions on the order of tenths of a micrometer and thicknesses of several nanometers. Homogeneous dispersion of the clay platelets in the polymer matrix is necessary to achieve those enhancements in polymer properties. Natural montmorillonite with the empirical formula Na0.33Mg0.33Al1.67(OH)2(Si4O10) contains exchangeable inorganic cations. The clay lamellae stack together with the positive sodium ions situated between the surfaces of the individual sheets to balance negatively charged oxygen atoms that are on the surfaces of the sheets. These surface charges contribute to strong electrostatic forces which hold the sheets together tightly. Exfoliation can be accomplished only with unusual measures. In preparing clay nanocomposites, we have taken two steps to try to reduce these interlamellar forces in order to promote the separation (exfoliation) of the sheets and the dispersion of the individual clay particles throughout the organic polymer matrix. In the first step, some of the surface Na(+) ions are replaced with Li(+) ions. Unlike sodium cations, the lithium cations migrate into the interior of the lamellae when the system is heated. Their departure from the surface reduces the surface charge and therefore the attractive forces between the sheets. The loss of alkali metal cations from the surface can be measured as the cation exchange capacity (CEC) of the clay. For example, we found that the CEC of montmorillonite clay was reduced by almost two thirds by treating it with lithium ions and heating to 250 C for 24 hr. Lesser heating has a smaller effect on the CEC. X-ray diffraction measurements show that the d-spacing decreased from ca. 1.34 to 0.97 nm, apparently a consequence of a collapse of the clay

  6. Immobilization of fungal laccase onto a nonionic surfactant-modified clay material: application to PAH degradation.

    PubMed

    Chang, Yi-Tang; Lee, Jiunn-Fwu; Liu, Keng-Hua; Liao, Yi-Fen; Yang, Vivian

    2016-03-01

    Nonionic surfactant-modified clay is a useful absorbent material that effectively removes hydrophobic organic compounds from soil/groundwater. We developed a novel material by applying an immobilized fungal laccase onto nonionic surfactant-modified clay. Low-water-solubility polycyclic aromatic hydrocarbons (PAHs) (naphthalene/phenanthrene) were degraded in the presence of this bioactive material. PAH degradation by free laccase was higher than degradation by immobilized laccase when the surfactant concentration was allowed to form micelles. PAH degradation by immobilized laccase on TX-100-modified clay was higher than on Brij35-modified clay. Strong laccase degradation of PAH can be maintained by adding surfactant monomers or micelles. The physical adsorption of nonionic surfactants onto clay plays an important role in PAH degradation by laccase, which can be explained by the structure and molecular interactions of the surfactant with the clay and enzyme. A system where laccase is immobilized onto TX-100-monomer-modified clay is a good candidate bioactive material for in situ PAHs bioremediation.

  7. CLAY AND CLAY-SUPPORTED REAGENTS IN ORGANIC SYNTHESES

    EPA Science Inventory

    CLAY AND CLAY-SUPPORTED REAGENTS HAVE BEEN USED EXTENSIVELY FOR SYNTHETIC ORGANIC TRANSFORMATIONS. THIS OVERVIEW DESCRIBES THE SALIENT STRUCTURAL PROPERTIES OF VARIOUS CLAY MATERIALS AND EXTENDS THE DISCUSSION TO PILLARED CLAYS AND REAGENTS SUPPORTED ON CLAY MATERIALS. A VARIET...

  8. Phosphoric acid purification through different raw and activated clay materials (Southern Tunisia)

    NASA Astrophysics Data System (ADS)

    Trabelsi, Wafa; Tlili, Ali

    2017-05-01

    This study concerns the purification of Tunisian phosphoric acid produced by the Tunisian Chemical Group (TCG), using raw and activated clays materials from Southern Tunisia. The Gafsa basin clays samples (Jebel Hamadi (JHM); Jebel Stah (JS) and the El Hamma sample (Jebel Aïdoudi (JAD)) were activated with 3 M, HCl solution. Phosphoric acid purification was performed on raw and activated clays. Mineralogical characterisation was carried out using the X-ray powder diffraction method and infrared absorption spectroscopy. Textural changes between raw and activated clays were identified using SEM observations and specific surface analysis. Jebel Hamadi clays were almost dominated by smectite associated with kaolinite and illite traces, while Jebel Stah and Jebel Aïdoudi clays were composed of the association of smectite, illite and kaolinite. It is worth noting that the position of the smectite (001) reflection increased after the acidic activation in all studied samples, indicating the relaxation of the smectite structure along the c-axis. This was corroborated by the increasing specific surface area of the clay particles with the activation process. The specific surface area was close to 50 m2/g and 200 m2/g, for raw and activated materials, respectively. The maximum phosphoric acid purification was obtained by using activated clays with 3 N HCl for 4 h. This performance correlated with the maximum of the external specific surface area which generated strong acid sites. Furthermore, the best results of phosphoric acids purification from TCG were obtained at a specific consumption equivalent to 30 Kg of clay/ton of P2O5. These results showed that the best phosphoric acid purification was yielded by Jebel Aïdoudi clay. In all cases, the highest organic carbon reduction rates in the phosphoric acid after filtration were obtained at 90°C.

  9. Organoclay hybrid materials as precursors of porous ZnO/silica-clay heterostructures for photocatalytic applications.

    PubMed

    Akkari, Marwa; Aranda, Pilar; Ben Haj Amara, Abdessalem; Ruiz-Hitzky, Eduardo

    2016-01-01

    In this study, ZnO/SiO2-clay heterostructures were successfully synthesized by a facile two-step process applied to two types of clays: montmorillonite layered silicate and sepiolite microfibrous clay mineral. In the first step, intermediate silica-organoclay hybrid heterostructures were prepared following a colloidal route based on the controlled hydrolysis of tetramethoxysilane in the presence of the starting organoclay. Later on, pre-formed ZnO nanoparticles (NP) dispersed in 2-propanol were incorporated under ultrasound irradiation to the silica-organoclay hybrid heterostructures dispersed in 2-propanol, and finally, the resulting solids were calcinated to eliminate the organic matter and to produce ZnO nanoparticles (NP) homogeneously assembled to the clay-SiO2 framework. In the case of montmorillonite the resulting materials were identified as delaminated clays of ZnO/SiO2-clay composition, whereas for sepiolite, the resulting heterostructure is constituted by the assembling of ZnO NP to the sepiolite-silica substrate only affecting the external surface of the clay. The structural and morphological features of the prepared heterostructures were characterized by diverse physico-chemical techniques (such as XRD, FTIR, TEM, FE-SEM). The efficiency of these new porous ZnO/SiO2-clay heterostructures as potential photocatalysts in the degradation of organic dyes and the removal of pharmaceutical drugs in water solution was tested using methylene blue and ibuprofen compounds, respectively, as model of pollutants.

  10. Characterization of Zeolite in Zeolite-Geopolymer Hybrid Bulk Materials Derived from Kaolinitic Clays.

    PubMed

    Takeda, Hayami; Hashimoto, Shinobu; Yokoyama, Hiroaki; Honda, Sawao; Iwamoto, Yuji

    2013-05-06

    Zeolite-geopolymer hybrid materials have been formed when kaolin was used as a starting material. Their characteristics are of interest because they can have a wide pore size distribution with micro- and meso-pores due to the zeolite and geopolymer, respectively. In this study, Zeolite-geopolymer hybrid bulk materials were fabricated using four kinds of kaolinitic clays (a halloysite and three kinds of kaolinite). The kaolinitic clays were first calcined at 700 °C for 3 h to transform into the amorphous aluminosilicate phases. Alkali-activation treatment of the metakaolin yielded bulk materials with different amounts and types of zeolite and different compressive strength. This study investigated the effects of the initial kaolinitic clays on the amount and types of zeolite in the resultant geopolymers as well as the strength of the bulk materials. The kaolinitic clays and their metakaolin were characterized by XRD analysis, chemical composition, crystallite size, (29)Si and (27)Al MAS NMR analysis, and specific surface area measurements. The correlation between the amount of zeolite formed and the compressive strength of the resultant hybrid bulk materials, previously reported by other researchers was not positively observed. In the studied systems, the effects of Si/Al and crystalline size were observed. When the atomic ratio of Si/Al in the starting kaolinitic clays increased, the compressive strength of the hybrid bulk materials increased. The crystallite size of the zeolite in the hybrid bulk materials increased with decreasing compressive strength of the hybrid bulk materials.

  11. Characterization of Zeolite in Zeolite-Geopolymer Hybrid Bulk Materials Derived from Kaolinitic Clays

    PubMed Central

    Takeda, Hayami; Hashimoto, Shinobu; Yokoyama, Hiroaki; Honda, Sawao; Iwamoto, Yuji

    2013-01-01

    Zeolite-geopolymer hybrid materials have been formed when kaolin was used as a starting material. Their characteristics are of interest because they can have a wide pore size distribution with micro- and meso-pores due to the zeolite and geopolymer, respectively. In this study, Zeolite-geopolymer hybrid bulk materials were fabricated using four kinds of kaolinitic clays (a halloysite and three kinds of kaolinite). The kaolinitic clays were first calcined at 700 °C for 3 h to transform into the amorphous aluminosilicate phases. Alkali-activation treatment of the metakaolin yielded bulk materials with different amounts and types of zeolite and different compressive strength. This study investigated the effects of the initial kaolinitic clays on the amount and types of zeolite in the resultant geopolymers as well as the strength of the bulk materials. The kaolinitic clays and their metakaolin were characterized by XRD analysis, chemical composition, crystallite size, 29Si and 27Al MAS NMR analysis, and specific surface area measurements. The correlation between the amount of zeolite formed and the compressive strength of the resultant hybrid bulk materials, previously reported by other researchers was not positively observed. In the studied systems, the effects of Si/Al and crystalline size were observed. When the atomic ratio of Si/Al in the starting kaolinitic clays increased, the compressive strength of the hybrid bulk materials increased. The crystallite size of the zeolite in the hybrid bulk materials increased with decreasing compressive strength of the hybrid bulk materials. PMID:28809241

  12. Analysis of the bacterial community found in clay wall material used in the construction of traditional Japanese buildings.

    PubMed

    Kitajima, Sakihito; Shiono, Takeshi; Ujihara, Tomomi; Sato, Hiroyuki

    2008-02-01

    Clay wall (also called mud wall in English and tsuchikabe in Japanese) material is used in traditional Japanese buildings. Clay wall material is manufactured by fermenting a mixture of clay, sand, and rice straw. A culture-independent study based on 16s rRNA sequences revealed that Clostridiales of Firmicutes, alpha-, gamma- and delta-proteobacteria of Proteobacteria, and Acidobacterium of Acidobacteria exist in the clay wall material. Of these, we focused on Clostridium and Geobacter and their possible roles in the degradation of the cellulose component of the straw and the reduction of ferric iron in the clay during fermentation.

  13. Assessment of the advanced clay bonded silicon carbide candle filter materials. Topical report, September 1995

    SciTech Connect

    Alvin, M.A.

    1995-07-01

    Advancements have been made during the past five years to not only increase the strength of the as-manufactured clay bonded silicon carbide candle filter materials, but also to improve their high temperature creep resistance properties. This report reviews these developments, and describes the results of preliminary qualification testing which has been conducted at Westinghouse prior to utilizing the advanced clay bonded silicon carbide filters in high temperature, pressurized, coal-fired combustion and/or gasification applications.

  14. Clay: An important raw material for prehistoric man

    NASA Astrophysics Data System (ADS)

    Wagner, U.; Gebhard, R.; Grosse, G.; Hutzelmann, T.; Murad, E.; Riederer, J.; Shimada, I.; Wagner, F. E.

    1998-12-01

    Early techniques of making pottery can be investigated by 57Fe Mössbauer spectroscopy. Iron is generally present in unpurified clays in concentrations of several percent. During firing, the iron undergoes characteristic changes of its chemical and physical state, depending on the kiln atmosphere and on the maximum firing temperature reached. These changes can be followed by Mössbauer spectroscopy. Firing techniques can often be reconstructed when spectra of laboratory and field fired samples are compared with those observed in ancient sherds.

  15. Organoclay hybrid materials as precursors of porous ZnO/silica-clay heterostructures for photocatalytic applications

    PubMed Central

    Akkari, Marwa; Aranda, Pilar; Ben Haj Amara, Abdessalem

    2016-01-01

    In this study, ZnO/SiO2-clay heterostructures were successfully synthesized by a facile two-step process applied to two types of clays: montmorillonite layered silicate and sepiolite microfibrous clay mineral. In the first step, intermediate silica–organoclay hybrid heterostructures were prepared following a colloidal route based on the controlled hydrolysis of tetramethoxysilane in the presence of the starting organoclay. Later on, pre-formed ZnO nanoparticles (NP) dispersed in 2-propanol were incorporated under ultrasound irradiation to the silica–organoclay hybrid heterostructures dispersed in 2-propanol, and finally, the resulting solids were calcinated to eliminate the organic matter and to produce ZnO nanoparticles (NP) homogeneously assembled to the clay–SiO2 framework. In the case of montmorillonite the resulting materials were identified as delaminated clays of ZnO/SiO2-clay composition, whereas for sepiolite, the resulting heterostructure is constituted by the assembling of ZnO NP to the sepiolite–silica substrate only affecting the external surface of the clay. The structural and morphological features of the prepared heterostructures were characterized by diverse physico-chemical techniques (such as XRD, FTIR, TEM, FE-SEM). The efficiency of these new porous ZnO/SiO2-clay heterostructures as potential photocatalysts in the degradation of organic dyes and the removal of pharmaceutical drugs in water solution was tested using methylene blue and ibuprofen compounds, respectively, as model of pollutants. PMID:28144545

  16. Laboratory reflectance spectra of clay minerals mixed with Mars analog materials: Toward enabling quantitative clay abundances from Mars spectra

    NASA Astrophysics Data System (ADS)

    Roush, Ted L.; Bishop, Janice L.; Brown, Adrian J.; Blake, David F.; Bristow, Thomas F.

    2015-09-01

    Quantitative estimates of clay minerals on the martian surface, via remote sensing observations, provide constraints on activity, timing, duration, and extent of aqueous processes and the geochemical environment in martian history. We describe an analytical study to begin enabling quantitative estimates of phyllosilicates when mixed with martian analog materials. We characterize the chemistry, mineralogy, particle size distribution, and reflectance spectra of the end-member materials: saponite, montmorillonite, pyroxene, and palagonitic soil. Reflectance spectra were obtained for physical mixtures of saponite and montmorillonite with pyroxene, and saponite with palagonitic soil. We analyzed the diagnostic phyllosilicate spectral signatures in the 2.2-2.4 μm wavelength region in detail for the mixtures. This involved fitting the observed ∼2.3 or ∼2.2 μm band depth, associated with the presence of saponite and montmorillonite, respectively, as a function of the abundance of these materials in the mixtures. Based upon the band depth of the spectral features we find that 3-5 wt.% of the clay minerals in the mixture with pyroxene can be recognized and at 25 wt.% their presence is indisputable in the mixtures. When the saponite is mixed with the lower albedo palagonitic soil, its presence is clearly distinguishable via the 1.4 and 2.3 μm features at 25 wt.% abundance. These relationships, between abundance and band depth, provide an ability to quantitatively address the amount of these materials in mixtures. The trends described here provide guidance for estimating the presence of phyllosilicates in matrices on the martian surface.

  17. Physical-chemical characterization of Tunisian clays for the synthesis of geopolymers materials

    NASA Astrophysics Data System (ADS)

    Selmani, S.; Essaidi, N.; Gouny, F.; Bouaziz, S.; Joussein, E.; Driss, A.; Sdiri, A.; Rossignol, S.

    2015-03-01

    Natural clay materials from Tunisia were examined as an aluminosilicate source for the synthesis of consolidated materials at low temperatures. Three clay samples were collected from the El Kef, Douiret and Gafsa basins and calcined at different temperatures. All of the samples were characterized using chemical and mineralogical analyses, thermogravimetry, dilatometry, and Fourier transform infrared spectroscopy (FTIR) measurements. The chemical (XRF) and mineralogical analyses (XRD and FTIR) indicated that all of the samples contained various amounts of kaolinite and quartz, followed by calcite, mica, palygorskite and gypsum. Curing produced a binder which did not significantly affect the physic-chemical properties of these clays. The obtained materials heterogeneous did not reach the geopolymerization stage, most likely because of their low kaolinite content. The addition of a suitable aluminosilicate to these clays is therefore recommended to produce homogeneous consolidated geopolymers. The synthesized materials obtained after the addition of metakaolin to the formulation to improve reactivity have interesting properties, thereby providing good potential for Tunisian clays in the synthesis of geopolymers.

  18. Analysis of the eukaryotic community and metabolites found in clay wall material used in the construction of traditional Japanese buildings.

    PubMed

    Kitajima, Sakihito; Kamei, Kaeko; Nishitani, Maiko; Sato, Hiroyuki

    2010-01-01

    Clay wall (tsuchikabe in Japanese) material for Japanese traditional buildings is manufactured by fermenting a mixture of clay, sand, and rice straw. The aim of this study was to understand the fermentation process in order to gain insight into the ways waste biomass can be used to produce useful materials. In this study, in addition to Clostridium, we suggested that the family Nectriaceae and the Scutellinia sp. of fungi were important in degrading cell wall materials of rice straw, such as cellulose and/or lignin. The microorganisms in the clay wall material produced sulfur-containing inorganic compounds that may sulfurate minerals in clay particles, and polysaccharides that give viscosity to clay wall material, thus increasing workability for plastering, and possibly giving water-resistance to the dried clay wall.

  19. Materials derived from synthetic organo-clay complexes as novel hydrodesulfurization catalyst supports.

    SciTech Connect

    Carrado, K. A.; Marshall, C. L.; Brenner, J. R.; Song, K.; Chemistry

    1998-01-01

    A series of mesoporous synthetic organo-clay complexes has been prepared by hydrothermal crystallization of gels containing silica, magnesium hydroxide, lithium fluoride, and an organic of choice, followed by calcination to remove the organics. The organic serves to impart structural order to the inorganic network that does not disappear upon its removal. The choice of organic modifier can be used to control the pore structure of the resulting mesoporous materials. Pore size distributions appear in some cases to be related to the type of polymer packing upon clay formation in situ. These materials are being explored as Co Mo hydrodesulfurization (HDS) catalyst supports. Preliminary HDS results show performance commensurate with commercial catalysis for the mesoporous materials when a model heavy oil feed is used (1 wt% S as dibenzothiophene in hexadecane). Temperature programmed reduction experiments of used catalysts suggest a relationship between HDS activity and ease of reduction of the CoMo/clay catalysts. Reactivity of the CoMo clay also correlates with the percentage of mesopore volume remaining after reaction. Losses in mesopore volume are largely recouped by recalcination, suggesting that reversible coke is formed inside the pore structure of clays faster than inside conventional alumina.

  20. New way of measurement of thermophysical properties of clay loam materials by transient methods

    NASA Astrophysics Data System (ADS)

    Boháč, Vlastimil; Dieška, Peter; Vretenár, Viliam; Lukáč, Vladimír

    2016-07-01

    The problem of the measurement of clay loam materials in plastic consistency is more or less difficult as they can change the shape during the long time measurements. The specimen thickness is expected as the constant during all the experiment measured by transient pulse method. In a case of plastic clay loam, it can change the form during the measurement because of the squeeze of the material even under the gravity condition. Thus the specimen surface wall should be reinforced by special dimensionally well-defined thin wall container. In this paper the special container in a form of thin tube rings bounded by central annular ring was constructed and used for the measurements. The heat source was inserted into the tube rings through the nozzle in the middle part and the thermocouple was inserted through the drilled openings at defined distance from the heat source. System clamped the heat source together with the rings at desired distance from the thermocouple. This distance represents the thickness of tested specimen. The soft plastic material fill the inner space of tube rings in such a way to fulfill the geometry conditions for this method. The need of soft clay loam material measurement is to test its thermal properties because of the interest to use it as the heat storage material below the buildings. The measured clay loam containing some moisture has quite high values of specific heat and thus the use of it as the heat storage material is promising.

  1. Clay pigment structure characterisation as a guide for provenance determination--a comparison between laboratory powder micro-XRD and synchrotron radiation XRD.

    PubMed

    Švarcová, Silvie; Bezdička, Petr; Hradil, David; Hradilová, Janka; Žižak, Ivo

    2011-01-01

    Application of X-ray diffraction (XRD)-based techniques in the analysis of painted artworks is not only beneficial for indisputable identification of crystal constituents in colour layers, but it can also bring insight in material crystal structure, which can be affected by their geological formation, manufacturing procedure or secondary changes. This knowledge might be helpful for art historic evaluation of an artwork as well as for its conservation. By way of example of kaolinite, we show that classification of its crystal structure order based on XRD data is useful for estimation of its provenance. We found kaolinite in the preparation layer of a Gothic wall painting in a Czech church situated near Karlovy Vary, where there are important kaolin deposits. Comparing reference kaolin materials from eight various Czech deposits, we found that these can be differentiated just according to the kaolinite crystallinity. Within this study, we compared laboratory powder X-ray micro-diffraction (micro-XRD) with synchrotron radiation X-ray diffraction analysing the same real sample. We found that both techniques led to the same results.

  2. Development of biodegradable foamlike materials based on casein and sodium montmorillonite clay

    USDA-ARS?s Scientific Manuscript database

    Biodegradable foamlike materials based on a naturally occurring polymer (casein protein) and sodium montmorillonite clay (Na+-MMT) were produced through a simple freeze-drying process. By utilizing DL-glyceraldehyde (GC) as a chemical cross-linking agent, the structural integrity of these new aeroge...

  3. Use of ground clay brick as a pozzolanic material to reduce the alkali-silica reaction

    SciTech Connect

    Turanli, L.; Bektas, F.; Monteiro, P.J.M

    2003-10-01

    The objective of this experimental study was to use ground clay brick (GCB) as a pozzolanic material to minimize the alkali-silica reaction expansion. Two different types of clay bricks were finely ground and their activity indices were determined. ASTM accelerated mortar bar tests were performed to investigate the effect of GCB when used to replace cement mass. The microstructure of the mortar was investigated using scanning electron microscopy (SEM). The results showed that the GCBs meet the strength activity requirements of ASTM. In addition, the GCBs were found to be effective in suppressing the alkali-silica reaction expansion. The expansion decreased as the amount of GCBs in the mortar increased.

  4. Polypropylene Nanocomposites from Porous Clay Materials: Application in Ethylene Scavenger Packaging Films

    NASA Astrophysics Data System (ADS)

    Prakobna, Kasinee; Magaraphan, Rathanawan; Manuspiya, Hathaikarn

    2007-03-01

    The PCH is interesting material to use as entrapping system owing to its structure provides high surface area with uniform and specific pore size. In this work, the PCH is synthesized within the galleries of Na-bentonite clay by the polymerization of tetraethoxysilane (TEOS) in the presence of surfactant micelles (cetyltrimethylammonium bromide and dodecylamine). In addition, a mesoporous clay with hybrid organic-inorganic PCH (HPCH) is modified via co-condensation reaction of TEOS and methyltriethoxysilane (MTS). Before the preparation of PCHs and HPCHs, the Na-bentonite clay was adjusted pH into 9, 7, 5 and 3. Furthermore, both PCH and HPCH are utilized as ethylene scavenger and blended with polypropylene (PP) for producing ethylene scavenging films in food packaging application. The eight samples of nanocomposites films including PCH-9, 7, 5, 3 and HPCH-9, 7, 5, 3 (numerals denote the pH-adjusted condition of Na-bentonite clay) will be measured oxygen and ethylene permeabilities; however, the present results obtained from PCH-9 and HPCH-9 nanocomposites films revealed that both oxygen and ethylene permeabilities of these films were less than that of PP virgin film. So these materials could be found new application in active packaging.

  5. Mesoporous materials derived from synthetic organo-clays as novel hydrodesulfurization catalysts

    SciTech Connect

    Carrado, K.A.; Marshall, C.L.; Brenner, J.R.

    1996-12-31

    Various pore size distributions are found for synthetic organo-clay complexes from which the organic portion has been removed via calcination. The clays are prepared by hydrothermal crystallization of gels containing silica, magnesium hydroxide, lithium fluoride, and an organic of choice. The organic serves to impart long-range structural order to the inorganic network that does not disappear upon its removal. Mesoporous materials are prepared from a host of organic modifiers. For example, pore diameters of 40-50{Angstrom} result from tetraethyl ammonium and celluloses, and polydimethyl diallyl ammonium imparts diameters of about 110{Angstrom} on average. These materials have begun to be explored as hydrodesulfurization (HDS) catalyst supports. Preliminary results show performance commensurate with commercial catalysts for the mesoporous materials when a model oil feed is used (1% dibenzothiophene in hexadecane). The target application is HDS of an actual heavy crude oil from California.

  6. Utilization of sludge waste from natural rubber manufacturing process as a raw material for clay-ceramic production.

    PubMed

    Vichaphund, S; Intiya, W; Kongkaew, A; Loykulnant, S; Thavorniti, P

    2012-12-01

    The possibility of utilization of the sludge waste obtained from the natural rubber manufacturing process as a raw material for producing clay ceramics was investigated. To prepared clay-based ceramic, the mixtures of traditional clay and sludge waste (10-30 wt%) were milled, uniaxilly pressed and sintered at a temperature between 1000 and 1200 degrees C. The effect of sludge waste on the properties of clay-based ceramic products was examined. The results showed that the amount of sludge waste addition had an effect on both sinterability and properties of the clay ceramics. Up to 30 wt% of sludge waste can be added into the clay ceramics, and the sintered samples showed good properties.

  7. Gas permeability of biochar-amended clay: potential alternative landfill final cover material.

    PubMed

    Wong, James Tsz Fung; Chen, Zhongkui; Ng, Charles Wang Wai; Wong, Ming Hung

    2016-04-01

    Compacted biochar-amended clay (BAC) has been proposed as an alternative landfill final cover material in this study. Biochar has long been proposed to promote crop growth, mitigate odor emission, and promote methane oxidation in field soils. However, previous studies showed that soil-gas permeability was increased upon biochar application, which will promote landfill gas emission. The objective of the present study is to investigate the possibility of using compacted BAC as an alternative material in landfill final cover by evaluating its gas permeability. BAC samples were prepared by mixing 425-μm-sieved peanut shell biochar with kaolin clay in different ratios (0, 5, 10, and 15 %, w/w) and compacting at different degrees of compactions (DOC) (80, 85, and 90 %) with an optimum water content of 35 %. The gas permeability of the BACs was measured by flexible wall gas permeameter and the microstructure of the BACs was analyzed by SEM with energy-dispersive x-ray spectroscopy (EDX). The results show that the effects of biochar content on BAC gas permeability is highly dependent on the DOC. At high DOC (90 %), the gas permeability of BAC decreases with increasing biochar content due to the combined effect of the clay aggregation and the inhibition of biochar in the gas flow. However, at low DOC (80 %), biochar incorporation has no effects on gas permeability because it no longer acts as a filling material to the retard gas flow. The results from the present study imply that compacted BAC can be used as an alternative final cover material with decreased gas permeability when compared with clay.

  8. Evaluating hydro-mechanical interactions of adjacent clay-based sealing materials

    NASA Astrophysics Data System (ADS)

    Kim, C.-S.; Dixon, D.

    Canada’s Nuclear Waste Management Organization (NWMO) is investigating various geological isolation concepts for Canada’s used reactor fuel (NWMO, 2005). These options are all based on the concept of multiple barriers that include Highly Compacted Bentonite (HCB), Dense Backfill (DBF), Light Backfill (LBF), and Gap Fill (GF). The hydraulic, mechanical, and other characteristics of these clay-based sealing materials have been examined previously, but typically in relative isolation (e.g., Dixon, 1999; Blatz, 2000; Siemens, 2006; Stroes-Gascoyne et al., 2006; Baumgartner et al., 2007). Information on how these clay-based sealing materials interact with each other is needed to understand the evolution and performance of the overall sealing system. A total of twenty-three (23) tests that examine the physical interaction of physically dissimilar clay-based sealing materials were installed and monitored at Atomic Energy of Canada Limited’s (AECL) geotechnical laboratory. This paper describes the process of water uptake, interaction between the components installed, and the role of groundwater salinity on water uptake as interpreted from these tests.

  9. Synthesis and Characterization of the Hybrid Clay- Based Material Montmorillonite-Melanoidin: A Potential Soil Model

    SciTech Connect

    V Vilas; B Matthiasch; J Huth; J Kratz; S Rubert de la Rosa; P Michel; T Schäfer

    2011-12-31

    The study of the interactions among metals, minerals, and humic substances is essential in understanding the migration of inorganic pollutants in the geosphere. A considerable amount of organic matter in the environment is associated with clay minerals. To understand the role of organic matter in the environment and its association with clay minerals, a hybrid clay-based material (HCM), montmorillonite (STx-1)-melanoidin, was prepared from L-tyrosine and L-glutamic acid by the Maillard reaction. The HCM was characterized by elemental analysis, nuclear magnetic resonance, x-ray photoelectron spectroscopy (XPS), scanning transmission x-ray microscopy (STXM), and thermal analysis. The presence of organic materials on the surface was confirmed by XPS and STXM. The STXM results showed the presence of organic spots on the surface of the STx-1 and the characterization of the functional groups present in those spots. Thermal analysis confirmed the existence of organic materials in the montmorillonite interlayer, indicating the formation of a composite of melanoidin and montmorillonite. The melanoidin appeared to be located partially between the layers of montmorillonite and partially at the surface, forming a structure that resembles the way a cork sits on the top of a champagne bottle.

  10. Stratigraphies of Apollo and Luna Highland Landing Sites and Provenances of Materials from the Perspective of Basin Impact Ejecta Modeling

    NASA Technical Reports Server (NTRS)

    Haskin, Larry A.; Korotev, Randy L.; Gillis, Jeffrey J.; Jolliff, Bradley L.

    2002-01-01

    What are the provenances of the non-mare materials collected at the Apollo and Luna sampling sites? Results from basin ejecta modeling suggest that much of it came from distant basins. Additional information is contained in the original extended abstract.

  11. Stratigraphies of Apollo and Luna Highland Landing Sites and Provenances of Materials from the Perspective of Basin Impact Ejecta Modeling

    NASA Technical Reports Server (NTRS)

    Haskin, Larry A.; Korotev, Randy L.; Gillis, Jeffrey J.; Jolliff, Bradley L.

    2002-01-01

    What are the provenances of the non-mare materials collected at the Apollo and Luna sampling sites? Results from basin ejecta modeling suggest that much of it came from distant basins. Additional information is contained in the original extended abstract.

  12. Electrostatic painting residues as an alternative raw material for red clay industry.

    PubMed

    Basegio, Tania; Machado, Andréa; Bernardes, Andréa Moura; Bergmann, Carlos Pérez

    2006-12-01

    In this study, the viability of using electrostatic painting residues--paint sludge--as a raw material to the red clay industry was investigated. Red clay-based ceramic masses containing electrostatic paint residues were formulated during the study. The clays were obtained from the Rio do Rastro deposit, in Gravataí, and were of the standard formulation used in industry. Different ceramic mass formulations with additions of 0.5, 1.0, 2.5 and 5.0 wt.% electrostatic painting residue in addition to a formulation with no residue addition (standard formulation), were evaluated. The samples were uniaxially pressed in a double-effect press and were fired in an electric oven at 900, 950 and 1000 degrees C. The firing at constant temperature lasted 8 h, and heating rate was 150 K h(-1). After processing the samples were characterized in terms of their physical and mechanical properties. Environmental compatibility was also considered by the evaluation of gaseous emissions and leaching and solubilization tests according to the Brazilian standards NBR 10.005 and NBR 10.006, respectively. The results showed that it was possible to produce ceramic materials containing electrostatic painting residues within their formulations.

  13. Mineralogy of Clay Raw Materials from Cote d'ivoire: Case of the Deposit from Katiola

    NASA Astrophysics Data System (ADS)

    Kpangni, E. B.; Andji, Y. Y. J.; Adouby, K.; Oyetola, S.; Kra, G.; Yvon, J.

    This study deals with two clays referenced K1 and K2, used in the local and traditional manufacture of pottery ware at Katiola. Those samples were analysed by X-rays diffraction, infrared spectroscopy and thermal differential and chemical techniques. The results show that the samples (K1 and K2) are mainly composed of montmorillonite, kaolinite and illite. Only K1 is inter-stratified. The mineralogical balance achieved from the reflection (001) of the oriented film, indicate for K1: 74.5% of montmorillonite; 13.5% of inter-stratified clay; 7% of kaolinite and 5.4% of illite and for K2: 73.4% of montmorillonite; 23.5% of kaolinite and 3.1% of illite. The results also indicate that the raw material may not be use only for pottery. It can be consider in the protection of the environment, cosmetic industry, vegetable oil treatment, medicine etc.

  14. A mechanism of basal spacing reduction in sodium smectitic clay materials in contact with DNAPL wastes.

    PubMed

    Ayral-Cinar, Derya; Otero-Diaz, Margarita; Demond, Avery H

    2016-09-01

    There has been concern regarding the possible attack of clays in aquitards, slurry walls and landfill liners by dense nonaqueous phase liquid (DNAPL) wastes, resulting in cracking. Despite the fact that a reduction in basal spacing in sodium smectitic clay materials has been linked to cracking, no plausible mechanism by which this reduction occurs in contact with waste DNAPLs has been formulated. To elucidate a mechanism, screening studies were conducted that showed that the combination of an anionic surfactant (AOT), a nonionic surfactant (TritonX-100) and a chlorinated solvent, tetrachloroethylene (PCE), could replicate the basal spacing reduction and cracking behavior of water-saturated bentonite caused by two waste DNAPLs obtained from the field. FTIR measurements of this system showed a displacement of the HOH bending band of water symptomatic of desiccation. Sorption measurements showed that the uptake of AOT by bentonite increased eight fold in the presence of TritonX-100 and PCE. The evidence presented here supports a mechanism of syneresis, involving the extraction of water from the interlayer space of the clay through the synergistic sorption of a nonionic and anionic surfactant mixture. It is speculated that the solvation of water in reverse micellar aggregates is the process driving the syneresis. Copyright © 2016. Published by Elsevier Ltd.

  15. Use of mix of clay/solid waste from steel works for civil construction materials.

    PubMed

    Oliveira, Geiza E; Holanda, José Nilson F

    2004-10-01

    The present study focuses on the use of solid waste generated by the steel works in Brazil for manufacturing clay-based structural products. The waste sample was characterized regarding chemical composition, X-ray diffraction, particle size, morphology, specific surface and plastic properties. The waste was added in gradual proportions to a kaolinitic clay from zero up to 3 wt.%. Ceramic bodies were formed by vacuum extrusion and fired at 950 degrees C. The physical-mechanical properties (linear shrinkage, water absorption, apparent density and flexural strength) of the resulting clay/solid waste mixtures were determined. In addition, leaching tests were performed according Brazilian Standards as well as a preliminary analysis of gases evolved during the thermal process. It was found that the solid waste is formed by irregular particles, ranging in size from 1 to 500 microm. The test results indicate that solid wastes generated by steel works can be used as filler in construction materials, thereby increasing reuse in an environmentally safe manner.

  16. Clay-Nucleic Acid Complexes: Characteristics and Implications for the Preservation of Genetic Material in Primeval Habitats

    NASA Astrophysics Data System (ADS)

    Franchi, Marco; Bramanti, Emilia; Morassi Bonzi, Laura; Luigi Orioli, Pier; Vettori, Cristina; Gallori, Enzo

    1999-05-01

    The equilibrium adsorption of three nucleic acids: chromosomal DNA, supercoiled plasmid DNA, and 25S rRNA, on the clay minerals, montmorillonite (M) and kaolinite (K), were studied. Adsorption of the nucleic acid on the clays was rapid and maximal after 90 min of contact time. Chromosomal DNA was adsorbed to a greater extent than plasmid DNA and RNA, and the adsorption was also greater on M than on K. Adsorption isotherms were of the L type, and a plateau was reached with all the complexes, with the exception of chromosomal DNA adsorbed on M. To determine where nucleic acids are adsorbed on clay minerals and the nature of the interaction, complexes were studied by X-ray diffraction (X-RD), electron microscopy, and Fourier transform infrared (FT-IR) spectroscopy. X-RD showed that nucleic acids did not penetrate the clay, indicating that the adsorption occurred primarily on the external surfaces of clay particles, as also suggested by electron microscopy observations. FT-IR spectra of clay-tightly bound nucleic acid complexes showed absorption bands that indicate a variation of the nucleic acids status as a consequence of their adsorption on clay. Data obtained suggested that the formation of clay-nucleic acid complex could have an important role in the preservation of genetic material in primeval habitats.

  17. Attenuation of landfill leachate by clay liner materials in laboratory columns: 2. Behaviour of inorganic contaminants.

    PubMed

    Thornton, S F; Lerner, D N; Tellam, J H

    2001-02-01

    The chemical attenuation of inorganic contaminants in methanogenic landfill leachate, spiked with heavy metals (Cd, Cd, Ni and Zn), by two UK clay liner materials was compared in laboratory columns over 15 months. Ammonium was attenuated by ion-exchange but this attenuation was finite and when exhausted, NH4 passed through the liners at concentrations found in the leachate. The breakthrough behaviour of NH4 could be described by a simple distribution coefficient. Heavy metals were attenuated by sorption and precipitation of metal sulphide and carbonate compounds near the top of the liner. Adequate SO4 and CaCO3 in the liner is necessary to ensure the long term retention of heavy metals, and pH buffering agents added to stabilise reactive metal fractions should be admixed with the liner. Some metals may not be chemically attenuated by clay liners due to the formation of stable complexes with organic and/or colloidal fractions in leachate. Flushing of the liners with oxygenated water after leachate caused mobilisation of attenuated contaminants. Sorbed NH4 was released by the liners but groundwater loadings were manageable. Re-oxidation of metal sulphides under these conditions resulted in the release of heavy metals from the liners when the pH buffering capacity was poor. Contaminant attenuation by the clay liners was similar and the attenuation of NH4 and heavy metals could be predicted from the geochemical properties of the liner using simple tests. A conceptual model of clay liner performance is presented. Chemical attenuation of inorganic pollutants can be included in containment liner design to produce a dual reactive-passive barrier for landfills.

  18. Mars: electric properties of clay materials in martian-like conditions to refine radar investigation.

    NASA Astrophysics Data System (ADS)

    Colantuono, Luca; Baliva, Antonio; Lauro, Sebastian; Mattei, Elisabetta; Marinangeli, Lucia; Pettinelli, Elena; Seu, Roberto

    2014-05-01

    The orbital radar instruments are giving new opportunities for planetary geological investigation regarding subsurface layering and geometry. Sedimentary deposits of paleolacustrine environments on Mars have shown the presence of various clay minerals . These clay deposits are very important in planetary exploration because they are strictly linked to the presence of water and to the capability of the analyzed environment to develop life and, as a consequence, to preserve fossilized life marker. The subsurface stratigraphy and geometry of sedimentary deposits on Mars are investigated by two orbiting radar instruments (SHARAD and MARSIS) and in the next future another radar instrument, a landing one, will be send on Mars (WISDOM). For small grain size sediments, like clay minerals, the dielectric properties have a strong impact on the penetration depth of the radar signal. We studied the correct evaluation of these properties and their correlation with chemical and mineralogical phases. The focus of this research is on the dielectric properties of natural clayey materials at different frequencies and temperature, evaluating the correlation among water content , temperature and electric properties. Several natural clayey material samples, considered as analogues to the Martian ones, have been collected from different geological settings in Italy and we analyzed their water content, mineralogical assemblage and chemical content and the correlation with the permittivity at different frequencies and temperatures using the Network Analyzer technique. We also changed the water content of the samples, and using the SHARAD, MARSIS and WISDOM operating frequencies, we measured the variation of permittivity and electric properties in the thermal range of 180 K to 298 K. The goal of the study is to refine the sounding depths of the radar investigation on Mars, exploring the possibility to identify clayey sedimentary layers analyzing the differences between the electric

  19. Material properties of hollow clay tile and existing mortar characterization study

    SciTech Connect

    Butala, M.B.; Jones, W.D.

    1993-10-01

    Several Buildings at the Department of Energy (DOE) Oak Ridge Y-12 Plant were constructed (circa 1950) using unreinforced hollow clay tile (UHCT) masonry walls, which act as shear walls to resist lateral forces. A comprehensive test program, managed by the Center for Natural Phenomena Engineering (CNPE) of Martin Marietta Energy Systems, Inc. (MMES), is under way to determine material properties of existing hollow clay tile walls that will be used to help determine the structural strength of those buildings. This paper presents the results of several types of material property tests of 4-in.- and 8-in.-thick hollow clay tiles. These tests include determination of weight, size, void area, net area and gross area, initial rate of absorption, absorption, modules of rupture, splitting tensile strength, and compressive strength. The tests were performed on old, reclaimed tiles and new tiles. A total of 336 tiles were tested. The stress-strain relationship for 40 specimens was also obtained. All testing was performed in accordance with ASTM standards and procedures developed by CNPE. This paper also presents the results of an investigation of mortar removed from the existing walls. The mortar characterization study was performed by Testwell Craig Materials Consultants (TCMC) under subcontract to MMES. Petrographic and chemical investigations were conducted on 18 mortar samples removed from four buildings at the plant. The primary purpose of the investigations was to evaluate the properties of existing mortar and provide a similar specification for the mortar to be used for construction of test specimens and test walls for the test program. The study showed variability in the mortars among buildings and among different locations within a building; it was concluded that an average mortar mix conforming to ASTM type N proportioned by volume of Portland cement, hydrated lime, and Tennessee river sand would be used to conduct further laboratory studies of masonry assemblages.

  20. Interfacial reactions between humic-like substances and lateritic clay: application to the preparation of "geomimetic" materials.

    PubMed

    Goure-Doubi, Herve; Martias, Céline; Lecomte-Nana, Gisèle Laure; Nait-Ali, Benoît; Smith, Agnès; Thune, Elsa; Villandier, Nicolas; Gloaguen, Vincent; Soubrand, Marilyne; Konan, Léon koffi

    2014-11-15

    The aim of this study was to understand the mechanisms responsible for the strengthening of "geomimetic" materials, especially the chemical bonding between clay and humic substances. The mineral matter is lateritic clay which mainly consists in kaolinite, goethite, hematite and quartz. The other starting products are fulvic acid (FA) and lime. The preparation of these geomimetic materials is inspired from the natural stabilization of soils by humic substances occurring over thousands of years. The present process involves acidic and alkaline reactions followed by a curing period of 18days at 60°C under a water saturated atmosphere. The acceleration of the strengthening process usually observed in soils makes this an original process for treatment of soils. The consolidation of the "geomimetic" materials could result from two major phenomena: (i) chemical bonding at the interface between the clay particles and iron compounds and the functional groups of the fulvic acid, (ii) a partial dissolution of the clay grains followed by the precipitation of the cementitious phases, namely calcium silicate hydrates, calcium aluminate hydrates and mixed calcium silicum and aluminum hydrates. Indeed, the decrease of the BET specific area of the lateritic clay after 24 h of reaction with FA added to the structural reorganization observed between 900 and 1000°C in the "geomimetic" material, and to the results of adsorption measurements, confirm the formation of organo-ferric complexes. The presence of iron oxides in clay, in the form of goethite, appears to be another parameter in favor of a ligand exchange process and the creation of binding bridges between FA and the mineral matter. Indeed all faces of goethite are likely to be involved in complexation reactions whereas in lateritic clay only lateral faces could be involved. The results of the adsorption experiments realized at a local scale will improve our understandings about the process of adsorption of FA on lateritic

  1. Potential Sites for Ice Nucleation on Aluminosilicate Clay Minerals and Related Materials.

    PubMed

    Freedman, Miriam Arak

    2015-10-01

    Few aerosol particles in clouds nucleate the formation of ice. The surface sites available for nucleus formation, which can include surface defects and functional groups, determine in part the activity of an aerosol particle toward ice formation. Although ice nucleation on particles has been widely studied, exploration of the specific sites at which the initial germ forms has been limited, but is important for predicting the microphysical properties of clouds, which impact climate. This Perspective focuses on what is currently known about surface sites for ice nucleation on aluminosilicate clay minerals, which are commonly found in ice residuals, as well as related materials.

  2. In situ corrosion studies on candidate container materials for the underground disposal of high level radioactive waste in Boom Clay

    SciTech Connect

    Kursten, B.; Iseghem, P. Van

    1999-07-01

    SCK{center{underscore}dot}CEN has developed in the early 1980's, with the support of NIRAS/ONDRAF and EC, an extensive in situ corrosion program to evaluate the long-term corrosion behavior of various candidate container materials for the disposal of conditioned high-level radioactive waste and spent fuel. The in situ corrosion experiments were performed in the underground research facility, HADES, situated in the Boom Clay formation at a depth of 225 meters below ground level. These experiments place the samples either in direct contact with clay (type I), in a humid clay atmosphere (type 2), or in a concrete saturated clay atmosphere (type 3). During the period 1985--1994, twelve in situ corrosion experiments were installed in the underground laboratory. The exploitation of these experiments ended in 1996. All samples were recuperated and analyzed. The purpose of this paper is to summarize and discuss the results from the type 1 corrosion experiments (samples in direct contact with Boom Clay). Surface analyses tend to indicate that the so-called corrosion-resistant materials, e.g. stainless steels, Ni- and Ti-alloys, remain intact after exposure to Boom Clay between 16 and 170 C, whereas carbon steel presents significant pitting corrosion. Carbon steel seems to be unsuitable for the Belgian repository concept (pits up to 240{micro}m deep are detected after direct exposure to the argillaceous environment for 2 years at 90 C). The stainless steels look very promising candidate container materials.

  3. Zr-doped TiO2 supported on delaminated clay materials for solar photocatalytic treatment of emerging pollutants.

    PubMed

    Belver, C; Bedia, J; Rodriguez, J J

    2017-01-15

    Solar light-active Zr-doped TiO2 nanoparticles were successfully immobilized on delaminated clay materials by a one-step sol-gel route. Fixing the amount of TiO2 at 65wt.%, this work studies the influence of Zr loading (up to 2%) on the photocatalytic activity of the resulting Zr-doped TiO2/clay materials. The structural characterization demonstrates that all samples were formed by a delaminated clay with nanostructured anatase assembled on its surface. The Zr dopant was successfully incorporated into the anatase lattice, resulting in a slight deformation of the anatase crystal and the reduction of the band gap. These materials exhibit high surface area with a disordered mesoporous structure formed by TiO2 particles (15-20nm) supported on a delaminated clay. They were tested in the solar photodegradation of antipyrine, usually used as an analgesic drug and selected as an example of emerging pollutant. High degradation rates have been obtained at low antipyrine concentrations and high solar irradiation intensities with the Zr-doped TiO2/clay catalyst, more effective than the undoped one. This work demonstrates the potential application of the synthesis method for preparing novel and efficient solar-light photocatalysts based on metal-doped anatase and a delaminated clay.

  4. Insight into removal kinetic and mechanisms of anionic dye by calcined clay materials and lime.

    PubMed

    Vimonses, Vipasiri; Jin, Bo; Chow, Christopher W K

    2010-05-15

    Our recent work reported that a mixed adsorbent with natural clay materials and lime demonstrated an enhanced capacity and efficiency to remove anionic Congo Red dye from wastewater. This study aims to investigate the removal kinetic and mechanisms of the mixed materials involved in the decolourisation of the dye to maximise their prospective applications for industrial wastewater treatment. The experimental results showed that dye removal was governed by combined physiochemical reactions of adsorption, ion-exchange, and precipitation. Ca-dye precipitation contributed over 70% total dye removal, followed by adsorption and ion-exchange. The dye removal kinetic followed the pseudo-second-order expression and was well described by the Freundlich isotherm model. This study indicated pH was a key parameter to govern the removal mechanisms, i.e. adsorption/coagulation at acidic pH and precipitation at basic condition. Yet, the overall removal efficiency was found to be independent to the operation conditions, resulting in more than 94% dye removal. This work revealed that the mixed clays and lime can be applied as alternative low-cost adsorbents for industrial wastewater treatment. Copyright (c) 2009 Elsevier B.V. All rights reserved.

  5. Thermal conductivity measurement in clay dominant consolidated material by Transient Hot-Wire method.

    NASA Astrophysics Data System (ADS)

    Garnier, J. P.; Gallier, J.; Mercx, B.; Dudoignon, P.; Milcent, D.

    2010-06-01

    The transient hot-wire (THW) technique is widely used for measurements of the thermal-conductivity of most fluids and some attempts have also been carried out for simultaneous measurements of the thermal-diffusivity with the same hot wire. This technique was also tried to determine thermal properties of soils by the mean of probes which can be considered as wire with some assumptions. The purpose of this paper is to validate the thermal conductivity measurement by the THW technique in geomaterials, composed of compacted sand + clay mineral that can be used for earth construction (Compacted Earth Brick). The thermal transfer behaviors are mainly governed by the texture and moisture of the geomaterials. Thus the investigations were performed (1) in media made of glass beads of different diameters in dry and saturated state in order to observe the role of grain sizes and saturation state on the wire temperature (Δt) measurements and (2) in the compacted clay-geomaterial at different moisture states. The Δt / ln(t) diagrams allow the calculation of two thermal conductivities. The first one, measured in the short time acquisition (< 1s), characterizes the microtexture of the material and its hydrated state. The second one, measured for longer time acquisitions, characterizes the mean thermal conductivity of the material.

  6. The material, morphological, and mechanical similarities between sensitive clay landslides and dry snow slab avalanches: Implications and applications

    NASA Astrophysics Data System (ADS)

    Gauthier, D.; Hutchinson, D. J.

    2012-04-01

    Recent research has suggested that certain similarities exist between the material properties, morphological expression, and mechanics of large landslides in sensitive clay soils (e.g. in Eastern Canada and Norway), and slab avalanches in dry seasonal snow (e.g. in Western Canada and Alpine countries). To further this concept, we review existing research, and highlight some previously unrecognized similarities between sensitive clay landslides and dry slab avalanches. For example, both snow and sensitive clay are highly porous with a meta-stable fabric or texture, show brittle yielding at high strain rates, and near complete loss of cohesion with extensive remoulding is observed in both. In both materials, yielding is structural and there is a corresponding volumetric collapse of the fabric following bond failure. Furthermore, slopes of sensitive clay and seasonal alpine snow are naturally layered, with variations grain size, density, stiffness, strength, etc., occurring over a variety of scales through the depth profile. Possible layering in both includes strong, thick strata overlying relatively thin, weak ones; these are primary features of the clay or snow, formed during deposition or by some subsequent metamorphic process that alters bonding or individual grains. Progressive failure in the fabric of a buried weak layer in snow leads to detachment of the overlying slab; this same process has been modeled successfully in sensitive clay. Observed triggering factors in sensitive clay landslides and slab avalanches include relatively minor, local loading, or some natural temporal material change acting on overlying layers, leading to a destabilization and failure in underlying layers. Slides are observed on very low angle or nearly flat slopes in both sensitive clay and snow. In both, bulk displacement or flow of the overlying snow or clay strata may not occur, despite an extensive basal failure. In those cases a large scale (e.g. 1-10 m) ribbed or 'thumbprint

  7. Enhancement of Plant Establishment on Dredged Material Sites with Mycorrhizal Fungi and Clay Amendments

    DTIC Science & Technology

    1989-10-01

    montmorillonite enhanced the growth of smooth brome grass. Topsoil, the clays attapulgite and kaolinite , and the commercial products Agrosoke anj Stawetwere...clays bentonite, attapulgite, kaolinite , and montmorillonite . Trade name and company addresses for the clays are listed in Table 1. Agrosoke and Stawet...desertcoZa, G. etunicatwn, and G. intraradice8. The clays attapulgite, ben- tonite, kaclinite,/and montmorillonite from various commercial sources were

  8. Stochastic modeling of filtrate alkalinity in water filtration devices: Transport through micro/nano porous clay based ceramic materials

    USDA-ARS?s Scientific Manuscript database

    Clay and plant materials such as wood are the raw materials used in manufacture of ceramic water filtration devices around the world. A step by step manufacturing procedure which includes initial mixing, molding and sintering is used. The manufactured ceramic filters have numerous pores which help i...

  9. Assessment of the surface areas of silica and clay in acid-leached clay materials using concepts of adsorption on heterogeneous surfaces.

    PubMed

    Nguetnkam, J P; Kamga, R; Villiéras, F; Ekodeck, G E; Razafitianamaharavo, A; Yvon, J

    2005-09-01

    Two clays of the areas of Kaélé and Kousseri (extreme North Cameroon) containing mainly smectites and minor amounts of kaolinite were activated with sulfuric acid (1 to 8 N). Crystal-chemical properties were studied using X-ray diffraction, Fourier transform infrared spectroscopy, and chemical analysis, while textural properties were analyzed by step-by-step nitrogen adsorption at 77 K and low-pressure quasi-equilibrium argon adsorption at 77 K. As is generally observed, smectite is more sensitive to acid leaching than kaolinite. As a result of smectite decomposition, amorphous Al-containing silica forms, leading to an increase in the specific surface area of the leached materials. The content of the clay minerals and amorphous silica can be estimated on the basis of changes in the chemical composition of the samples upon acid leaching. As far as adsorption energy distributions derived from low-pressure argon derivative adsorption isotherms are concerned, the main modifications occur when 1 N sulfuric acid is used, due to the replacement of calcium and sodium compensating cations by protons. When higher acid concentrations are used, variations in adsorption energy distribution can be assigned to the presence of amorphous silica. It was possible to model experimental adsorption energy distributions as weighted sums of argon adsorption energy distributions obtained on (i) 1 N samples representing protonated clays and (ii) a silica gel used as a reference aluminous silica. Using such an approach, increasing acid concentration results in an increase in the surface area of silica, whereas the surface area of the remaining clay minerals remains roughly constant.

  10. Chemically specific multiscale modeling of clay-polymer nanocomposites reveals intercalation dynamics, tactoid self-assembly and emergent materials properties.

    PubMed

    Suter, James L; Groen, Derek; Coveney, Peter V

    2015-02-01

    A quantitative description is presented of the dynamical process of polymer intercalation into clay tactoids and the ensuing aggregation of polymer-entangled tactoids into larger structures, obtaining various characteristics of these nanocomposites, including clay-layer spacings, out-of-plane clay-sheet bending energies, X-ray diffractograms, and materials properties. This model of clay-polymer interactions is based on a three-level approach, which uses quantum mechanical and atomistic descriptions to derive a coarse-grained yet chemically specific representation that can resolve processes on hitherto inaccessible length and time scales. The approach is applied to study collections of clay mineral tactoids interacting with two synthetic polymers, poly(ethylene glycol) and poly(vinyl alcohol). The controlled behavior of layered materials in a polymer matrix is centrally important for many engineering and manufacturing applications. This approach opens up a route to computing the properties of complex soft materials based on knowledge of their chemical composition, molecular structure, and processing conditions. © 2014 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Molecular simulation of preferential adsorption of CO2 over CH4 in Na-montmorillonite clay material

    NASA Astrophysics Data System (ADS)

    Yang, Nannan; Liu, Shuyan; Yang, Xiaoning

    2015-11-01

    Grand canonical Monte Carlo simulations have been conducted to study the adsorption of carbon dioxide and methane, as well as their binary mixtures on Na-montmorillonite clay material. It was found that the adsorption behavior near the clay structure for the two species is distinctively different. The Na-montmorillonite clay shows obviously high adsorption capacity for CO2, as compared with CH4. The adsorption behavior and mechanism have been characterized by the interlayer interfacial structures and isosteric heats of adsorption. Meanwhile, the mixture adsorption demonstrates that CO2 molecules with enhanced adsorption strength are able to competitively replace CH4 molecules within the clay structure. The high separation selectivity of CO2 over CH4 implies the possibility of separating CO2 from natural gas mixtures using the clay minerals. The interlayer sodium cations and negatively charged clay surface can provide enhanced interaction with CO2 molecules that have high quadrupole moment, which is responsible for the higher adsorption loading of CO2.

  12. Development of biodegradable foamlike materials based on casein and sodium montmorillonite clay.

    PubMed

    Pojanavaraphan, Tassawuth; Magaraphan, Rathanawan; Chiou, Bor-Sen; Schiraldi, David A

    2010-10-11

    Biodegradable foamlike materials based on a naturally occurring polymer (casein protein) and sodium montmorillonite clay (Na+ -MMT) were produced through a simple freeze-drying process. By utilizing DL-glyceraldehyde (GC) as a chemical cross-linking agent, the structural integrity of these new aerogels were remarkably improved when compared to those of the control system (without GC), with a minimal increase in the density from 0.11 to 0.12 g cm⁻³. The degree of perfection of the foamlike structures was another parameter that had a significant influence on the physical and thermal performances of the low density composites. The biodegradability of the aerogels was investigated in terms of the carbon dioxide (CO₂) evolution for up to 8 weeks in compost media under controlled conditions.

  13. Geotectonic provenance of Malopolska and Lysogory crustal blocks, southern Poland: evidence from Nd isotopic composition of clastic material

    NASA Astrophysics Data System (ADS)

    Walczak, Aleksandra

    2013-04-01

    Nd isotopic composition of clastic material is used to reconstruct the geotectonic history of Małopolska and Lysogory blocks in southern Poland. These crustal blocks are situated within the Trans European Suture Zone (TESZ), the enigmatic tectonic domain that separates the old Precambrian Platform from the Alpine and Variscan orogenic mobile belts of western Europe. The TESZ is extending from North Sea in the NW to Denmark, north German through Poland, Ukraine until the Black Sea in the SE with the distance exceeding 2000 km. The primary configuration of blocks within the TESZ and their provenance are still a matter of debate. Malopolska and Lysogory reveal significant differences in their Ediacaran to Silurian sedimentary evolution and tectonic development. They were considered as an integral part of the paleocontinent of Baltica mostly based on occurrence of faunas characteristic of the Baltic realm. On the other hand, the detailed geophysical and other geological data rather indicates affinities with the Peri-Gondwana plates. This is why the accretion scenarios of Małopolska and Łysogóry play important role in the understanding of the late Precambrian/early Paleozoic geotectonic history of the European lithosphere. In addition to provenance data of detrital zircons and muscovites, which were collected in the past primarily from coarse-grained clastics, the present Nd isotopic studies have been performed on various clastic rocks present in the Cambrian sedimentary successions of Malopolska and Lysogory. The study revealed significant differences in the Nd model ages (TDM) and ɛNd values of the investigated clastic rocks. In the Malopolska block the ɛNd values, from -5.5 to -8.5, are more radiogenic than those of Lysogory, which range from -9.6 to -11.1. The Cambrian clastics show a wide spectrum model ages both in Malopolska and Lysogory. In the former the model ages range from 1.52 Ga to 2.35 Ga, whereas in the latter the spectrum is from 1.86 Ga to 2

  14. Provenance analysis using Raman spectroscopy of carbonaceous material: A case study in the Southern Alps of New Zealand

    NASA Astrophysics Data System (ADS)

    Nibourel, Lukas; Herman, Frédéric; Cox, Simon; Beyssac, Olivier; Lavé, Jérôme

    2016-04-01

    Detrital provenance analyses in orogenic settings, in which sediments are collected at the outlet of a catchment, have become an important tool to estimate how erosion varies in space and time. Here we present how Raman Spectroscopy on Carbonaceous Material (RSCM) can be used for provenance analysis. RSCM provides an estimate of the peak temperature (RSCM-T) experienced during metamorphism. We show that we can infer modern erosion patterns in a catchment by combining new measurements on detrital sands with previously acquired bedrock data. We focus on the Whataroa catchment in the Southern Alps of New Zealand and exploit the metamorphic gradient that runs parallel to the main drainage direction. To account for potential sampling biases, we also quantify abrasion properties using flume experiments and measure the total organic carbon content in the bedrock that produced the collected sands. Finally, we integrate these parameters into a mass-conservative model. Our results first demonstrate that RSCM-T can be a powerful tool for detrital studies. The relative ease of data acquisition allows for a robust statistical provenance analysis with a high spatial resolution. Second, we find that spatial variations in tracer concentration and erosion intensity have a first-order control on the RSCM-T distributions, even though our flume experiments reveal that weak lithologies produce substantially more fine particles than do more durable lithologies. This result implies that sand specimens are good proxies for mapping spatial variations in erosion when the bedrock concentration of the target mineral is quantified. The modeling suggests highest present-day erosion rates (in Whataroa catchment) are not situated at the range front, as might be expected from the long-term metamorphic rock exhumation pattern, but about 10 km into the mountain belt. This closely matches the pattern of maximum rain fall and highest short-term (contemporary) inter-seismic uplift.

  15. Using fugacity to predict volatile emissions from layered materials with a clay/polymer diffusion barrier

    NASA Astrophysics Data System (ADS)

    Yuan, Huali; Little, John C.; Marand, Eva; Liu, Zhe

    Structural insulated panels (SIPs) have significant environmental and energy advantages. However, the tight structure that results may cause degraded indoor air quality and the potential release of volatile organic compounds (VOCs) from these layered materials must be considered. A physically based model for predicting VOC emissions from multi-layer materials is described. Fugacity is used to eliminate the concentration discontinuities at the interface between layers. This avoids an obstacle associated with numerically simulating mass transfer in composite materials. The numerical model is verified for a double-layer system by comparing predicted concentrations to those obtained with a previously published analytical model. In addition, hexanal emissions from multi-layer SIPs are simulated to demonstrate the usefulness of the fugacity approach. Finally, the multi-layer model is used to investigate the impact that clay/polyurethane nanocomposite diffusion barriers can have on VOC emissions. Indoor gas-phase concentrations can be greatly reduced with a barrier layer on the surface, thereby minimizing the environmental impact of SIPs.

  16. Properties of bentonite clay as buffer material in high-level waste geological disposal. Part I: Chemical species contained in bentonite

    SciTech Connect

    Takahashi, M.; Muroi, M.; Inoue, A.; Aoki, M.; Takizawa, M.; Ishigure, K.; Fujita, N.

    1987-02-01

    Bentonite clay is one of the most promising candidates for use as buffer material in the geological disposal systems of high-level waste. However, very little has been reported on the ionic species contained in bentonite clay itself, especially the anion species. Chemical analyses of bentonite clay materials were carried out. It was found that the major anion species contained in the bentonite clay materials are SO/sub 4//sup 2-/, Cl/sup -/, and CO/sub 2/ species. The amounts of these differ among the clay samples depending on the origins and the processing of the clay materials. A clay material used in a series of our experiments was also analyzed for cation species contained, and adsorption experiments were carried out for the major ions contained in the clay materials. No adsorption of the anions on the clay particles was observed, and it was found that the adsorption of Na/sup +/ can be explained as the ion exchange equilibrium between Na/sup +/ and H/sup +/.

  17. Adsorption-regeneration by heterogeneous Fenton process using modified carbon and clay materials for removal of indigo blue.

    PubMed

    Almazán-Sánchez, Perla Tatiana; Solache-Ríos, Marcos J; Linares-Hernández, Ivonne; Martínez-Miranda, Verónica

    2016-01-01

    Indigo blue dye is mainly used in dyeing of denim clothes and its presence in water bodies could have adverse effects on the aquatic system; for this reason, the objective of this study was to promote the removal of indigo blue dye from aqueous solutions by iron and copper electrochemically modified clay and activated carbon and the saturated materials were regenerated by a Fenton-like process. Montmorillonite clay was modified at pH 2 and 7; activated carbon at pH 2 and pH of the system. The elemental X-ray dispersive spectroscopy analysis showed that the optimum pH for modification of montmorillonite with iron and copper was 7 and for activated carbon was 2. The dye used in this work was characterized by infrared. Unmodified and modified clay samples showed the highest removal efficiencies of the dye (90-100%) in the pH interval from 2 to 10 whereas the removal efficiencies decrease as pH increases for samples modified at pH 2. Unmodified clay and copper-modified activated carbon at pH 2 were the most efficient activated materials for the removal of the dye. The adsorption kinetics data of all materials were best adjusted to the pseudo-second-order model, indicating a chemisorption mechanism and the adsorption isotherms data showed that the materials have a heterogeneous surface. The iron-modified clay could be regenerated by a photo-Fenton-like process through four adsorption-regeneration cycles, with 90% removal efficiency.

  18. Description of Arundel Clay ornithomimosaur material and a reinterpretation of Nedcolbertia justinhofmanni as an “Ostrich Dinosaur”: biogeographic implications

    PubMed Central

    2017-01-01

    The fossil record of dinosaurs from the Early Cretaceous of Eastern North America is scant, especially since a few stratigraphic units from the east are fossiliferous. Among these stratigraphic units, the Arundel Clay of the eastern seaboard has produced the best-characterized dinosaur faunas known from the Early Cretaceous of Eastern North America. The diverse dinosaur fauna of the Arundel Clay has been thoroughly discussed previously, but a few of the dinosaur species originally described from the Arundel Clay are still regarded as valid genera. Much of the Arundel material is in need of review and redescription. Among the fossils of dinosaurs from this stratigraphic unit are those referred to ornithomimosaurs. Here, the researcher describes ornithomimosaur remains from the Arundel Clay of Prince George’s County, Maryland which may be from two distinct ornithomimosaur taxa. These remains provide key information on the theropods of the Early Cretaceous of Eastern North America. Recent discoveries of small theropod material from the Arundel Clay possibly belonging to ornithomimosaurs are also reviewed and described for the first time. The description of the Arundel material herein along with recent discoveries of basal ornithomimosaurs in the past 15 years has allowed for comparisons with the coelurosaur Nedcolbertia justinhofmanni, suggesting the latter animal was a basal ornithomimosaur rather than a “generalized” coelurosaur as it was originally described. Comparisons between the Arundel ornithomimosaur material and similar Asian and European specimens suggest that both extremely basal ornithomimosaurs and more intermediate or derived forms may have coexisted throughout the northern hemisphere during the Early Cretaceous. PMID:28286718

  19. Provenance Analysis using Raman Spectroscopy of Carbonaceaous Material: a case study in the Southern Alps of New Zealand

    NASA Astrophysics Data System (ADS)

    Herman, F.; Nibourel, L.; Cox, S.; Beyssac, O.; Lave, J.

    2015-12-01

    Detrital provenance analyses in orogenic settings, in which sediments are collected at the outlet of a catchment, have become an important tool to estimate how erosion varies in space and time. Here we present how Raman Spectroscopy on Carbonaceous Material (RSCM) can be used for provenance analysis. RSCM provides an estimate of the peak temperature (RSCM-T) experienced during metamorphism. We show that we can infer modern erosion patterns in a catchment by combining new measurements on detrital sands with previously acquired bedrock data. We focus on the Whataroa catchment in the Southern Alps of New Zealand and exploit the metamorphic gradient that runs parallel to the main drainage direction. To account for potential sampling biases, we also quantify abrasion properties using flume experiments and measure the total organic carbon content in the bedrock that produced the collected sands. Finally, we integrate these parameters into a mass-conservative model. Our results first demonstrate that RSCM-T can be used for detrital studies. Second, we find that spatial variations in tracer concentration and erosion have a first-order control on the RSCM-T distributions, even though our flume experiments reveal that weak lithologies produce substantially more fine particles than do more durable lithologies. This result implies that sand specimens are good proxies for mapping spatial variations in erosion when the bedrock concentration of the target mineral is quantified. The modeling suggests highest present-day erosion rates (in Whataroa catchment) are not situated at the range front, as might be expected from the long-term metamorphic rock exhumation pattern, but about 10 km into the mountain belt near the location of maximum rain fall and highest short-term (contemporary) inter-seismic uplift.

  20. Constructing wetlands: measuring and modeling feedbacks of oxidation processes between plants and clay-rich material

    NASA Astrophysics Data System (ADS)

    Saaltink, Rémon; Dekker, Stefan C.; Griffioen, Jasper; Wassen, Martin J.

    2016-04-01

    Interest is growing in using soft sediment as a building material in eco-engineering projects. Wetland construction in the Dutch lake Markermeer is an example: here the option of dredging some of the clay-rich lake-bed sediment and using it to construct 10.000 ha of wetland will soon go under construction. Natural processes will be utilized during and after construction to accelerate ecosystem development. Knowing that plants can eco-engineer their environment via positive or negative biogeochemical plant-soil feedbacks, we conducted a six-month greenhouse experiment to identify the key biogeochemical processes in the mud when Phragmites australis is used as an eco-engineering species. We applied inverse biogeochemical modeling to link observed changes in pore water composition to biogeochemical processes. Two months after transplantation we observed reduced plant growth and shriveling as well as yellowing of foliage. The N:P ratios of plant tissue were low and were affected not by hampered uptake of N but by enhanced uptake of P. Plant analyses revealed high Fe concentrations in the leaves and roots. Sulfate concentrations rose drastically in our experiment due to pyrite oxidation; as reduction of sulfate will decouple Fe-P in reducing conditions, we argue that plant-induced iron toxicity hampered plant growth, forming a negative feedback loop, while simultaneously there was a positive feedback loop, as iron toxicity promotes P mobilization as a result of reduced conditions through root death, thereby stimulating plant growth and regeneration. Given these two feedback mechanisms, we propose that when building wetlands from these mud deposits Fe-tolerant species are used rather than species that thrive in N-limited conditions. The results presented in this study demonstrate the importance of studying the biogeochemical properties of the building material and the feedback mechanisms between plant and soil prior to finalizing the design of the eco-engineering project.

  1. Cu(II) and Zn(II) adsorption capacity of three different clay liner materials.

    PubMed

    Musso, T B; Parolo, M E; Pettinari, G; Francisca, F M

    2014-12-15

    Sorption of Cu(II) and Zn(II) on three natural clays meeting the international requirements for use as liners was evaluated by means of batch tests. The purpose of this research was to determine the retention capacities of the clays for metal cations commonly present in urban solid waste leachates. The pH and ionic strength conditions were set at values frequently found in real leachates. The changes observed in the XRD patterns and FTIR spectra upon adsorption can be considered an evidence of clay-metal electrostatic interaction. The Langmuir model was found to best describe the sorption processes, offering maximum sorption capacities from 8.16 to 56.89 mg/g for Cu(II) and from 49.59 to 103.83 mg/g for Zn(II). All samples remove more Zn(II) than Cu(II), which may be related to the different geometry of the hydrated Cu(II) cation. The total amount of metal sorption was strongly influenced by the total specific surface area, the presence of carbonates and the smectite content of the clays. In addition to their known quality as physical barriers, the adsorbed amounts obtained indicate the suitability of the tested clays to contribute to the retardation of Cu(II) and Zn(II) transport through clay liners.

  2. Derivation, Parameterization and Validation of a Sandy-Clay Material Model for Use in Landmine Detonation Computational Analyses

    NASA Astrophysics Data System (ADS)

    Grujicic, M.; Pandurangan, B.; Coutris, N.; Cheeseman, B. A.; Roy, W. N.; Skaggs, R. R.

    2010-04-01

    A set of large-strain/high-deformation-rate/high-pressure material models for sand-based soils with different saturation levels and clay and gravel contents was recently proposed and validated in our study, and the same has been extended in this study to include clay-based soils of different saturation levels and sand contents. The model includes an equation of state which reveals the material response under hydrostatic pressure, a strength model which captures material elastic-plastic response under shear, and a failure model which defines the laws and conditions for the initiation and evolution of damage and ultimate failure of the material under negative pressure and/or shear. The model was first parameterized using various open-literature experimental results and property correlation analyses and, then, validated by comparing the computational results obtained in an ANSYS/Autodyn-based transient non-linear dynamics analysis of detonation of a landmine buried in sandy-clay with their experimental counterparts.

  3. Ball clay

    USGS Publications Warehouse

    Virta, Robert L.

    2010-01-01

    The article reports on the global market performance of ball clay in 2009 and presents an outlook for its 2010 performance. Several companies mined ball call in the country including Old Hickey Clay Co., Kentucky-Tennessee Clay Co., and H.C. Spinks Clay Co. Information on the decline in ball clay imports and exports is also presented.

  4. Ball clay

    USGS Publications Warehouse

    Virta, R.L.

    2006-01-01

    In 2005, four companies including H.C. Spinks Clay, Kentucky-Tennessee Clay, Old Hickory Clay and Unimin mined ball clay in four states. Based on a preliminary survey of the ball clay industry, production reached 1.32 Mt valued at $53.3 million. Tennessee was the leading ball clay producer state with 61% of domestic production, followed by Texas, Mississippi and Kentucky.

  5. Clays, specialty

    USGS Publications Warehouse

    Virta, R.L.

    1998-01-01

    Part of a special section on the state of industrial minerals in 1997. The state of the specialty clay industry worldwide for 1997 is discussed. The specialty clays mined in the U.S. are ball clay, fuller's earth, bentonite, fire clay, and kaolin. Sales of specialty clays in the U.S. were around 17 Mt in 1997. Approximately 53 kt of specialty clays were imported.

  6. Screening of heavy metal containing waste types for use as raw material in Arctic clay-based bricks.

    PubMed

    Belmonte, Louise Josefine; Ottosen, Lisbeth M; Kirkelund, Gunvor Marie; Jensen, Pernille Erland; Vestbø, Andreas Peter

    2016-11-10

    In the vulnerable Arctic environment, the impact of especially hazardous wastes can have severe consequences and the reduction and safe handling of these waste types are therefore an important issue. In this study, two groups of heavy metal containing particulate waste materials, municipal solid waste incineration (MSWI) fly and bottom ashes and mine tailings (i.e., residues from the mineral resource industry) from Greenland were screened in order to determine their suitability as secondary resources in clay-based brick production. Small clay discs, containing 20 or 40% of the different particulate waste materials, were fired and material properties and heavy metal leaching tests were conducted before and after firing. Remediation techniques (washing in distilled water and electrodialytical treatment) applied to the fly ash reduced leaching before firing. The mine tailings and bottom ash brick discs obtained satisfactory densities (1669-2007 kg/m(3)) and open porosities (27.9-39.9%). In contrast, the fly ash brick discs had low densities (1313-1578 kg/m(3)) and high open porosities (42.1-51. %). However, leaching tests on crushed brick discs revealed that heavy metals generally became more available after firing for all the investigated materials and that further optimisation is therefore necessary prior to incorporation in bricks.

  7. Use of natural clays as sorbent materials for rare earth ions: Materials characterization and set up of the operative parameters.

    PubMed

    Iannicelli-Zubiani, Elena Maria; Cristiani, Cinzia; Dotelli, Giovanni; Gallo Stampino, Paola; Pelosato, Renato; Mesto, Ernesto; Schingaro, Emanuela; Lacalamita, Maria

    2015-12-01

    Two mineral clays of the montmorillonite group were tested as sorbents for the removal of Rare Earths (REs) from liquid solutions. Lanthanum and neodymium model solutions were used to perform uptake tests in order to: (a) verify the clays sorption capability, (b) investigate the sorption mechanisms and (c) optimize the experimental parameters, such as contact time and pH. The desorption was also studied, in order to evaluate the feasibility of REs recovery from waters. The adsorption-desorption procedure with the optimized parameters was also tested on a leaching solution obtained by dissolution of a dismantled NdFeB magnet of a hard-disk. The clays were fully characterized after REs adsorption and desorption by means of X-ray powder diffraction (XRPD) and X-ray photoelectron spectroscopy (XPS); the liquid phase was characterized via Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES) analyses. The experimental results show that both clays are able to capture and release La and Nd ions, with an ion exchange mechanism. The best total efficiency (capture ≈ 50%, release ≈ 70%) is obtained when the uptake and release processes are performed at pH=5 and pH=1 respectively; in real leached scrap solutions, the uptake is around 40% but release efficiency is strongly decreased passing from a mono-ion system to a real system (from 80% to 5%). Furthermore, a strong matrix effect is found, with the matrix largely affecting both the uptake and the release of neodymium.

  8. Ball clay

    USGS Publications Warehouse

    Virta, R.L.

    2001-01-01

    Part of the 2000 annual review of the industrial minerals sector. A general overview of the ball clay industry is provided. In 2000, sales of ball clay reached record levels, with sanitary ware and tile applications accounting for the largest sales. Ball clay production, consumption, prices, foreign trade, and industry news are summarized. The outlook for the ball clay industry is also outlined.

  9. Ball clay

    USGS Publications Warehouse

    Virta, R.L.

    2007-01-01

    The article offers information on ball clay. Among the companies that mine ball clay in the U.S. are H.C. Spinks Clay, Kentucky-Tennessee Clay and Old Hickory Clay. In 2006, an estimated 1.2 million tons of the mineral was sold or used domestically and exported. Forty-percent of the total sales is accounted for ceramic floor and wall tile followed by sanitaryware and miscellaneous ceramics. Its average value was $ 45 per ton in 2006.

  10. Ball clay

    USGS Publications Warehouse

    Virta, R.L.

    2011-01-01

    The article discusses the latest developments in the global ball clay mining industry, particularly in the U.S., as of June 2011. It cites several firms that are involved in ball clay mining in the U.S., including HC Spins Clay Co. Inc., the Imerys Group and Old Hickory Clay Co. Among the products made from ball clay are ceramic tiles, sanitaryware, as well as fillers, extenders and binders.

  11. Common clay and shale

    USGS Publications Warehouse

    Virta, R.L.

    2000-01-01

    Part of the 1999 Industrial Minerals Review. The clay and shale market in 1999 is reviewed. In the U.S., sales or use of clay and shale increased from 26.4 million st in 1998 to 27.3 million st in 1999, with an estimated 1999 value of production of $143 million. These materials were used to produce structural clay products, lightweight aggregates, cement, and ceramics and refractories. Production statistics for clays and shales and for their uses in 1999 are presented.

  12. Dewatering of industrial clay wastes

    SciTech Connect

    Smelley, A.G.; Scheiner, B.J.; Zatko, J.R.

    1980-01-01

    As a part of research conducted to effect pollution a dewatering technique that allows for disposal of clay wastes, for reuse of water now lost with clays, and for reclamation of mined land was developed. The technique utilizes a high-molecular-weight nonionic polyethylene oxide polymer (PEO) that has the ability to flocculate and dewater materials containing clay wastes. In laboratory experiments, coal-clay waste, potash-clay brine slurry, phosphatic clay waste, uranium tailings, and talc tailings were successfully consolidated. Coal-clay waste was consolidated from 3.6 to 57%; potash-clay brine slurry was consolidated from 3.8 to 35%; phosphatic clay waste from 15.6 to 49%; uranium tailings from 15.4 to 67%; tailings from talc production from 9.7 to 53%; and an acidic TiO/sub 2/ slurr slurry from 1.68 to 30%.

  13. Antimicrobial nanocomposites based on natural modified materials: a review of carbons and clays.

    PubMed

    Martynková, Grazyna Simha; Valásková, Marta

    2014-01-01

    The review is focused on the recent research and development of antimicrobial nanocomposites based on selected carbon nanomaterials and natural nanoclay minerals. The nanocomposites comprised of two or several components, where at least one presents antimicrobial properties, are discussed. Yet the most popular agent remains silver as nanoparticle or in ionic form. Second, broadly studied group, are organics as additives or polymeric matrices. Both carbons and clays in certain forms possess antimicrobial properties. A lot of interest is put on to research graphene oxide. The low-environmental impact technologies-based on sustainable biopolymers have been studied. Testing of antimicrobial properties of nanomaterials is performed most frequently on E. coli and S. aureus bacterias.

  14. Ball clay

    USGS Publications Warehouse

    Virta, R.L.

    2013-01-01

    Four companies — H.C. Spinks Clay Co., Inc., Imerys, Old Hickory Clay Co. and Unimin Corp. — mined ball clay in five U.S. states in 2012. Production, on the basis of preliminary data, was 900 kt (992,000 st), with an estimated value of $42.3 million. This was a slight increase in tonnage from 886 kt (977,000 st), with a value of $40.9 million in 2011. Tennessee was the leading ball clay producing state, with 63 percent of domestic production, followed by Texas, Mississippi, Kentucky and Indiana. Reported ball clay production from Indiana probably was fire clay rather than ball clay. About 69 percent of total ball clay production was airfloat, 20 percent was crude and 11 percent was water-slurried.

  15. Fire clay

    USGS Publications Warehouse

    Virta, R.L.

    2011-01-01

    The article discusses the latest developments in the fire clay industry, particularly in the U.S., as of June 2011. It claims that the leading fire clay producer in the U.S. is the state of Missouri. The other major producers include California, Texas and Washington. It reports that the use of heavy clay products made of fire clay like brick, cement and lightweight aggregate has increased slightly in 2010.

  16. Clays, common

    USGS Publications Warehouse

    Virta, R.L.

    1998-01-01

    Part of a special section on the state of industrial minerals in 1997. The state of the common clay industry worldwide for 1997 is discussed. Sales of common clay in the U.S. increased from 26.2 Mt in 1996 to an estimated 26.5 Mt in 1997. The amount of common clay and shale used to produce structural clay products in 1997 was estimated at 13.8 Mt.

  17. Clay Houses

    ERIC Educational Resources Information Center

    Pedro, Cathy

    2011-01-01

    In this article, the author describes a project designed for fourth-graders that involves making clay relief sculptures of houses. Knowing the clay houses will become a family heirloom makes this lesson even more worth the time. It takes three classes to plan and form the clay, and another two to underglaze and glaze the final products.

  18. Clay Houses

    ERIC Educational Resources Information Center

    Pedro, Cathy

    2011-01-01

    In this article, the author describes a project designed for fourth-graders that involves making clay relief sculptures of houses. Knowing the clay houses will become a family heirloom makes this lesson even more worth the time. It takes three classes to plan and form the clay, and another two to underglaze and glaze the final products.

  19. Common clay and shale

    USGS Publications Warehouse

    Virta, R.L.

    2004-01-01

    Part of the 2003 industrial minerals review. The legislation, production, and consumption of common clay and shale are discussed. The average prices of the material and outlook for the market are provided.

  20. Fire clay

    USGS Publications Warehouse

    Virta, R.L.

    2013-01-01

    Four companies mined fire clay in three states in 2012. Production, based on a preliminary survey of the fire clay industry, was estimated to be 230 kt (254,000 st) valued at $6.98 million, an increase from 215 kt (237,000 st) valued at $6.15 million in 2011. Missouri was the leading producing state, followed by Colorado and Texas, in decreasing order by quantity. The number of companies mining fire clay declined in 2012 because several common clay producers that occasionally mine fire clay indicated that they did not do so in 2012.

  1. Study of sorption-retarded U(VI) diffusion in Hanford silt/clay material.

    PubMed

    Bai, Jing; Liu, Chongxuan; Ball, William P

    2009-10-15

    A diffusion cell method was applied to measure the effective pore diffusion coefficient (Dp) for U(VI) under strictly controlled chemical conditions in a silt/clay sediment from the U.S. Department of Energy Hanford site, WA. "Inward-flux" diffusion studies were conducted in which [U(VI)] in both aqueous and solid phases was measured as a function of distance in the diffusion cell under conditions of constant concentration at the cell boundaries. A sequential extraction method was developed to measure sorbed contaminant U(VI) in the solid phase containing extractable background U(VI). The effect of sorption kinetics on U(VI) interparticle diffusion was evaluated by comparing sorption-retarded diffusion models with sorption described either as equilibrium or intraparticle diffusion-limited processes. Both experimental and modeling results indicated that (1) a single pore diffusion coefficient can simulate the diffusion of total aqueous U(VI), and (2) the local equilibrium assumption (LEA) is appropriate for modeling sorption-retarded diffusion under the given experimental conditions. Dp of 1.6-1.7 x 10(-6) cm2/s was estimated in aqueous solution at pH 8.0 and saturated with respect to calcite, as relevant to some subsurface regions of the Hanford site.

  2. Study of sorption-retarded U(VI) diffusion in Hanford silt/clay material

    SciTech Connect

    Bai, Jing; Liu, Chongxuan; Ball, William P.

    2009-10-15

    A diffusion cell method was developed to measure the effective aqueous diffusion coefficient for U(VI) under strictly controlled chemical conditions within the inter-particle pores of silt/clay sediment from the DOE Hanford site, WA. "Inward-flux” diffusion studies were conducted in which U(VI) concentrations in both aqueous and solid phases were measured as a function of distance into the cell under conditions of constant concentration at the cell boundaries. A sequential extraction method was developed to measure sorbed U(VI) content in the solid phase, while accounting for the non-negligible extractable background U(VI). U(VI) diffusion data were found to be consistent with a model that assumed that: 1) a single effective aqueous diffusion coefficient could be used to simulate the coupled diffusion of various aqueous U(VI) species, and 2) the local equilibrium assumption (LEA) is appropriate for modeling the effects of sorption under the given experimental conditions. An effective aqueous diffusion coefficient (De) of 1.6x10^-6 cm2/s was obtained under conditions of pH 8.0 and calcite saturation that are relevant to the subsurface conditions at some regions of the Hanford site. The developed experimental techniques provide a practical approach for measuring effective aqueous U(VI) diffusivity in sorptive porous media.

  3. The composition and origin of Ghana medicine clays

    PubMed Central

    van Dongen, Bart E.; Fraser, Sharon E.; Insoll, Timothy

    2011-01-01

    The mineral, organic and elemental composition of medicine clays from three shrines in the Tong Hills in northern Ghana (Gbankil, Kusanaab, and Yaane) are assessed to ascertain what additives they might contain and the implications for their recognition, for example in archaeological contexts. These are clays that are widely used for healing purposes being perceived efficacious in curing multiple ailments and which are given a divine provenance, but their collection is ascribed human agency. The Yaane clay is also supplied as part of the process of obtaining the right to operate the shrine elsewhere making it widely dispersed. Organic geochemical analyses revealed a predominance of plant-derived material with a substantial contribution of microbial origin. Based on these (supported by elemental and mineral analyses), no unnatural organic material could be detected, making an exogenous contribution to these clays unlikely. The implications are that these are wholly natural medicinal substances with no anthropogenic input into their preparation, as the traditions suggest. The very similar mineralogy of all the clays, including a non-medicine clay sampled, suggests that, unless the geology radically differed, differentiating between them analytically in an archaeological contexts would be doubtful. PMID:21810043

  4. Element distribution patterns in the ordovician Galena group, Southeastern Minnesota: Indicators of fluid flow and provenance of terrigenous material

    USGS Publications Warehouse

    Lively, R.S.; Morey, G.B.; Mossler, J.H.

    1997-01-01

    As part of a regional geochemical investigation of lower Paleozoic strata in the Hollandale embayment of southeastern Minnesota, elemental concentrations in acid-insoluble residues were determined for carbonate rock in the Middle Ordovician Galena Group. Elemental distribution patterns within the insoluble residues, particularly those of Ti, Al, and Zr, show that the Wisconsin dome and the Wisconsin arch, which contributed sediment to the embayment prior to Galena time, continued as weak sources of sediment during this period. In contrast, trace metals commonly associated with Mississippi Valley-type lead-zinc mineralization, including Pb, Zn, Cu, Ag, Ni, Co, As, and Mo, show dispersal patterns that are independent of those associated with primary depositional phenomena. These trace metals are concentrated in southern Minnesota in carbonate rocks near the interface between limestone- and dolostone-dominated strata. Dispersal patterns imply that the metals were carried by a north-flowing regional ground-water system. The results show that the geochemical attributes of insoluble residues can be used to distinguish provenance and transport directions of primary sediments within a depositional basin from effects of subsequent regional ground-water flow systems.

  5. Fire clay

    USGS Publications Warehouse

    Virta, R.L.

    2006-01-01

    In 2005, six companies mined fire clay in Missouri, Ohio and South Carolina. Production was estimate to be 300 kt with a value of $8.3 million. Missouri was the leading producer state followed by Ohio and South Carolina. For the third consecutive year, sales and use of fire clays have been relatively unchanged. For the next few years, sales of fire clay is forecasted to remain around 300 kt/a.

  6. Ball clay

    USGS Publications Warehouse

    Virta, R.L.

    2000-01-01

    Part of the 1999 Industrial Minerals Review. The state of the ball clay industry in 1999 is presented. Record highs in the sales and use of ball clay were attained in 1999 due to the continued strength of the U.S. economy. U.S. production was estimated at 1.25 million st for the year, with more than half of that amount mined in Tennessee. Details of the consumption, price, imports, and exports of ball clay in 1999 and the outlook for ball clay over the next few years are provided.

  7. Inorganic raw materials economy and provenance of chipped industry in some stone age sites of northern and central Italy.

    PubMed

    Bietti, Amilcare; Boschian, Giovanni; Crisci, Gino Mirocle; Danese, Ermanno; De Francesco, Anna Maria; Dini, Mario; Fontana, Federica; Giampietri, Alessandra; Grifoni, Renata; Guerreschi, Antonio; Liagre, Jérémie; Negrino, Fabio; Radi, Giovanna; Tozzi, Carlo; Tykot, Robert

    2004-06-01

    An opportunistic and local choice of raw materials is typically attested in the Lower and Middle Paleolithic industries throughout Italy. The quality of the raw material usually affected the flaking technology and quality of the products. In the Upper Paleolithic and the Mesolithic, raw material procurement strategies were more complex. Flint was exploited both locally, in areas where abundant outcrops of raw materials were available (such as the Lessini mountains), and in distant localities, after which it was transported or exchanged over medium/long distances. Different routes of exchange were thus followed in the various periods; good reconstruction of these routes have been provided by a study of the Garfagnana sites in Northern Tuscany, and the Mesolithic deposit of Mondeval de Sora (Dolomites). An interesting example of a Late Upper Paleolithic flint quarry and workshop were found in Abruzzo, in the San Bartolomeo shelter. The extended trade of obsidian from Lipari, Palmarola and Sardinia to the Italian Peninsula is attested in the Neolithic, with some differences concerning the age and different areas.

  8. Geophagic clay materials from Nigeria: a potential source of heavy metals and human health implications in mostly women and children who practice it.

    PubMed

    Lar, U A; Agene, J I; Umar, A I

    2015-04-01

    Geophagy is a common practice among certain cultural groups especially women in some rural communities in Nigeria. The safety of eating such clays in terms of their heavy metal composition has not been ascertained, neither is the link between them and disease conditions established in geophagists. The analysis of field survey data reveals that the majority (about 90 %) of the women did not go beyond secondary school education. The geology of an area has a direct influence on the chemical composition of the soils. Therefore, this research was carried out to determine the mineralogical and the heavy metal content of some geophagic clay materials from Nigeria. All the geophagic clay materials are hydrated silicates of either Al, (Na and Ca), (Al and Mg), or/and (Mg and Fe). The concentration levels of Na, Al, Ca, Fe, Mg, Cu, and Zn are tolerable and apparently could serve as a veritable source of mineral nutrients deficient in the human body. An assessment of the level of contamination of heavy metals on the basis of the index of geo-accumulation (I(geo)) shows that Cr, Cu, Zn, Co, and Ni (all with I(geo) < 1) did not contaminate the clay materials. On the contrary, they are extremely contaminated by As, Cd and Se (I(geo) = >5), and are moderately to strongly contaminated by Pb and Sb (I (geo) = 2-3). In terms of health risk assessment, the presence of heavy metals such as As, Cd, Pb, Se, and Sb with a health risk index (HRI) >1, renders the geophagic clays unsafe for human consumption. Similarly, Al, Fe, and Na are in excess in the clay (HRI ⋙ 1) posing serious human health risks. Thus, the ingestion of geophagic clay materials by pregnant women and children when it contains heavy metals like Pb, As, Cd, Se, and Sb poses the risk of some medical disorders and should therefore be considered a public health problem. Since geophagic practice will persist despite civilization, we advocate finding ways of reducing heavy metal pollutants in geophagic clays through

  9. Frictional properties of clay-rich fault materials along a megasplay fault in the Nankai subduction zone for intermediate to high-velocities

    NASA Astrophysics Data System (ADS)

    Tsutsumi, A.; Fabbri, O.; Karpoff, A.; Ujiie, K.

    2011-12-01

    Recently reported experimental result on frictional properties of clay-rich materials collected from a major splay fault within the Nankai accretionary complex revealed that velocity dependence of the clay-rich fault rocks and the wall rocks almost always showed velocity strengthening at slow slip rates (0.03-0.1 mm/s) [Ikari et al., 2009, GRL]. This frictional behavior at the slow rates is consistent with the fault stabilizing model by the presence of velocity-strengthening clays. Recently, high-velocity frictional data of the clay-rich fault materials recovered from the splay fault have become also available, which are relevant to coseismic slip at velocities of higher than 1 m/s [Ujiie and Tsutsumi, 2010, GRL]. The high-velocity experiments have revealed that at seismic slip rates frictional strength becomes lower and Dc becomes larger than the rate- and state-dependent friction laws predict. Therefore, frictional constitutive parameters estimated for slow slip rates (<~1 mm/s) may not be applicable for a range of higher seismic slip rates. Here, we present results from a series of frictional experiments over a range of slip velocities from 0.0026 to 260 mm/s, with > 150 mm of displacements on clay-rich fault materials from the major splay fault within the Nankai accretionary complex (a megasplay fault zone) for water saturated condition. All of the samples tested in this study were collected at Site C0004 during the IODP expedition 316. Friction experiments were conducted on the samples using a rotary-shear, intermediate- to high-velocity friction testing machine. Experimental results reveal that there are both velocity-weakening and velocity-strengthening fault materials for slip velocities from 0.026 to ~26 mm/s. The velocity weakening behavior could provide a condition to initiate unstable fault motion at shallow depths along the splay fault. On the contrary, velocity strengthening behavior may affect to stabilize the propagation process of earthquake nuclei

  10. Polyurethane rigid foam, a proven thermal insulating material for applications between +130°C and -196°C

    NASA Astrophysics Data System (ADS)

    Demharter, Anton

    Polyurethanes are high molecular weight polymers based on the polyaddition of polyfunctional hydroxyl-group containing compounds and polyisocyanates. A wide variety of properties can be tailored to fulfil the requirements of different applications: soft to hard, plastic, elastic or thermoset, compact or foamed. Compared with other insulating materials, PUR rigid foam is highly competitive. There are five product-related advantages: lowest thermal conductivity, high mechanical and chemical properties at both high and low temperatures, all major international fire safety requirements can be satisfied, the ability to form sandwich structures with various facer materials, and the new generation of PUR is CFC-free and recyclable. Rigid polyurethane foams perform well in most areas of low-temperature insulations. Products in density ranging from approximately 30 to 200 kg m -3 withstand temperatures down to -196°C. Typical applications are: refrigerated vehicles, road and rail tankers, vessels for refrigerated cargo, pipelines, liquid gas tanks for LPG and LNG and cryogenic wind tunnels. The paper presents applications, corresponding properties of the rigid foams used, and also other insulating materials in competition to PUR are discussed.

  11. Composite TiO2/clays materials for photocatalytic NOx oxidation

    NASA Astrophysics Data System (ADS)

    Todorova, N.; Giannakopoulou, T.; Karapati, S.; Petridis, D.; Vaimakis, T.; Trapalis, C.

    2014-11-01

    TiO2 photocatalyst received much attention for air purification applications especially for removal of air pollutants like NOx, VOCs etc. It has been established that the activity of the photocatalyst can be significantly enhanced by its immobilization onto suitable substrates like inorganic minerals, porous silica, hydroxyapatite, adsorbent materials like activated carbon, various co-catalysts such as semiconductors, graphene, reduced graphite oxide, etc. In the present work, photocatalytic composite materials consisted of mineral substrate and TiO2 in weight ratio 1:1 were manufactured and examined for oxidation and removal of nitric oxides NOx (NO and NO2). Commercial titania P25 (Evonik-Degussa) and urea-modified P25 were used as photocatalytically active components. Inorganic minerals, namely kunipia, talk and hydrotalcite were selected as supporting materials due to their layered structure and expected high NOx adsorption capability. Al3+ and Ca2+ intercalation was applied in order to improve the dispersion of TiO2 and its loading into the supporting matrix. The X-ray diffraction analysis and Scanning Electron Microscopy revealed the binary structure of the composites and homogeneous dispersion of the photocatalyst into the substrates. The photocatalytic behavior of the materials in NOx oxidation and removal was investigated under UV and visible light irradiation. The composite materials exhibited superior photocatalytic activity than the bare titania under both types of irradiation. Significant visible light activity was recorded for the composites containing urea-modified titania that was accredited to the N-doping of the semiconductor. Among the different substrates, the hydrotalcite caused highest increase in the NOx removal, while among the intercalation ions the Ca2+ was more efficient. The results were related to the improved dispersion of the TiO2 and the synergetic activity of the substrates as NOx adsorbers.

  12. Neodymium and strontium isotopic study of Australasian tektites - New constraints on the provenance and age of target materials

    NASA Technical Reports Server (NTRS)

    Blum, Joel D.; Papanastassiou, D. A.; Wasserburg, G. J.; Koeberl, C.

    1992-01-01

    The Nd and Sr isotopic compositions of Australasian tectites (including two flanged Australian tectites, two low-SiO2 Muong Nong-type tectites, and three high-SiO2 Muong Nong-type tectites) and the Nd, Sm, Sr, and Rb concentrations were investigated by isotope-dilution thermal ionization mass spectrometry, and the Sm-Nd and Rb-Sr isotope systematics were used to study the characteristics of the parental material. It is shown that the Nd and Sr isotopic data provide evidence that all Australasian tektites were derived from a single sedimentary formation with a narrow range of stratigraphic ages close to 170 Ma. It is suggested that all of the Australasian tektites were derived from a single impact event and that the australites represent the upper part of a melt sheet ejected at high velocity, whereas the indochinites represent melts formed at a lower level in the target material distributed closer to the area of the impact.

  13. White clays of Pennsylvania

    USGS Publications Warehouse

    Hosterman, John W.

    1984-01-01

    The white clays of Pennsylvania are composed chiefly of kaolinite and various amounts of illite. Most of the white clays are silty and a few are sandy. Quartz or chert is the only nonclay mineral in the whitest material; goethite is also present in the colored samples high in iron. The average alumina content is slightly more than 20 percent in samples from three clay pits and less than 15 percent in samples from five clay pits. The white clay deposits are found in eastern, south-central, and central Pennsylvania. They occur in rocks of the Appalachian basin that range in age from Cambrian to Devonian; however, their age of formation is Cretaceous or later. Some of the deposits are the result of katamorphic alteration, and some are the result of weathered material being transported and deposited in sinkaoles or caverns. The presence of alunite in one deposit suggests the possibility that the clay may be the result of both katamorphic and hydrothermal alteration.

  14. Physical response of backfill materials to mineralogical changes in a basalt environment. [Sand-clay mixture containing 25% bentonite

    SciTech Connect

    Couture, R.A.; Seitz, M.G.

    1983-01-01

    Backfill materials surrounding waste canisters in a high-level nuclear waste repository are capable of ensuring very slow flow of groundwater past the canisters, and thereby increase the safety of the repository. However, in the design of a repository it will be necessary to allow for possible changes in the backfill. In this experimental program, changes in permeability, swelling behavior, and plastic behavior of the backfill at the temperatures, pressures, and radiation levels expected in a repository are investigated. The emphasis is on investigation of relevant phenomena and evaluation of experimental procedures for use in licensing procedures. The permeability of a slightly compacted sand-clay mixture containing 25% bentonite, with a dry bulk density of 1.59 g/cm/sup 3/, was determined to be 0.9 x 10/sup -18/ m/sup 2/ in liquid water at 25 and 200/sup 0/C, respectively. This is sufficiently low to demonstrate the potential effectiveness of proposed materials. In practice, fractures in the host rock may form short circuits around the backfill, so an even lower flow rate is probable. However, alteration by any of several mechanisms is expected to change the properties of the backfill. Crushed basalt plus bentonite is a leading candidate backfill for a basalt repository. Experiments show that basalt reacts with groundwater vapor or with liquid groundwater producing smectites, zeolites, silica, and other products that may be either beneficial or detrimental to the long-term performance of the backfill. Concentration of groundwater salts in the backfill by evaporation would cause immediate, but possibly reversible, reduction of the swelling abaility of bentonite. Moreover, under some circumstances, gamma radiolysis of moist air in the backfill could produce up to 0.5 mole of nitric acid or ammonia per liter of pore space. 27 references, 7 figures, 4 tables.

  15. Fire clay

    USGS Publications Warehouse

    Virta, R.L.

    2012-01-01

    Five companies mined fire clay in four states in 2011. Production, based on a preliminary survey of the fire clay industry, was estimated to be 240 kt (265,000 st), valued at $7.68 million, an increase from 216 kt (238,000 st), valued at $6.12 million in 2010. Missouri was the leading producing state, followed by Texas, Washington and Ohio, in decreasing order by quantity.

  16. Electrokinetics of pure clay minerals revisited

    SciTech Connect

    Sondi, I.; Biscan, J.; Pravdic, V.

    1996-03-25

    Clay minerals have long attracted the attention of colloid scientists. This paper considers, specifically, their important role in the transport of various contaminants from land to sea, e.g., metal ions and organic detrital and man-made material in watercourses. Advance in experimental techniques have enabled precise characterization of clays and then electrokinetic experiments at high electrolyte concentrations, such as in seawater. Three of the most important clay minerals encountered in suspended matter in natural waters, montmorillonite, illite, and chlorite, were prepared in a very pure state. Electrokinetic experiments were done in pure aqueous single and complex electrolyte solutions and in solutions in which natural organic matter was simulated using a humic substance, fulvic acid, of defined provenance and properties, typical of riverine waters. An isoelectric point was found at pH 5.0 {+-} 0.2 for chlorite; none were found for illite and montmorillonite. Only Ca{sup 2+} showed a charging effect on chlorite, indeed a reversal of sign from negative to positive at 1 {times} 10{sup {minus}3} mol dm{sup {minus}3}. Addition of fulvic acid affected only chlorite, illite less, and Na montmorillonite not at all.

  17. Clay Minerals

    SciTech Connect

    Mueller, Karl T.; Sanders, Rebecca L.; Washton, Nancy M.

    2014-03-14

    Clay minerals are important components of the environment and are involved or implicated in processes such as the uptake of pollutants and the release of nutrients and as potential platforms for a number of chemical reactions. Owing to their small particle sizes (typically, on the order of microns or smaller) and mixing with a variety of other minerals and soil components, advanced characterization methods are needed to study their structures, dynamics, and reactivities. In this article, we describe the use of solid-state NMR methods to characterize the structures and chemistries of clay minerals. Early one-pulse magic-angle spinning (MAS) NMR studies of 27Al and 29Si have now been enhanced and extended with new studies utilizing advanced methodologies (such as Multiple Quantum MAS) as well as studies of less-sensitive nuclei. In additional work, the issue of reactivity of clay minerals has been addressed, including studies of reactive surface area in the environment. Utilizations of NMR-sensitive nuclides within the clay minerals themselves, and in molecules that react with specific sites on the clay mineral surfaces, have aided in understanding the reactivity of these complex aluminosilicate systems.

  18. Analytical Characterization of Natural Clay

    NASA Astrophysics Data System (ADS)

    El-Sheikhy, Refat; Al-Shamrani, Mosleh

    2010-10-01

    The current paper introduces the study of morphology and electronic microscopy characterization of one type of the smectite Saudi nano clay montmorillonite type. During the last decade, nanotechnology achieved a recognized progress in many fields based mainly on synthesized materials. Much attention is devoted to produce natural nano particles. It was found that the clay is one of the rare materials which have platelets of nano scale size. The nano clay minerals are found in different types. It is investigated that the nano clay minerals have super properties which can not be found in the other materials. The Kingdom of Saudi Arabia has many zones having different types of good nano clays. These nano clays are found in certain mixtures with other different materials such as Mg, Ca, Fe and others. By developing an innovated technique we could extract Saudi Arabian nano clay with high grade purity. The results are very interesting. The produced nano clay particles are with good quality and super properties. It can be used in many fields of nanocomposites.

  19. Ball clay

    USGS Publications Warehouse

    Virta, R.L.

    2012-01-01

    Four companies — H.C. Spinks Clay Co., Inc., Imerys Group, Old Hickory Clay Co., and Unimin Corp. — mined ball clay in four states in 2011. Production, on the basis of preliminary data, was 940 kt (1.04 million st) with an estimated value of $44.2 million. This is a 3-percent increase in tonnage from 912 kt (1.01 million st) with a value of $41.3 million that was produced in 2010. Tennessee was the leading producing state with 63 percent of domestic production, followed by Texas, Mississippi and Kentucky. About 69 percent of production was airfloat, 20 percent was crude and 11 percent was water-slurried.

  20. The change in bioavailability of organic matter associated with clay-based buffer materials as a result of heat and radiation treatment

    SciTech Connect

    Stroes-Gascoyne, S.; Haveman, S.A.; Vilks, P.

    1997-12-31

    Compacted clay-based buffer surrounds corrosion-resistant waste containers in the Canadian concept for nuclear fuel waste disposal. Clays naturally contain small quantities of organic matter that may be resistant to bacterial degradation. The containers with highly radioactive material would subject the surrounding buffer to both heat and radiation. Both could potentially break down complex organic material to smaller, more bioavailable compounds. This could stimulate microbial growth and possibly affect gas production, microbially-influenced corrosion or radionuclide migration. Experiments were carried out in which buffer was heated at 60 and 90 C for periods of 2, 4 and 6 weeks, in some cases followed by irradiation to 25 kGy. Unheated buffer was also irradiated to 25 and 50 kGy at different moisture contents. The treated materials were subsequently suspended in distilled water, shaken for 24 h and centrifuged to remove the solids. The 0.22 {micro}m filter-sterilized leachates were inoculated with equal volumes of fresh groundwater and incubated at room temperature for 10 d to determine the increase in total and viable bacteria compared to a groundwater control. Results indicated that leachates from buffer subjected to heat, radiation or combinations of these, had a stimulating effect on both total and viable cell counts in groundwater, compared to unamended groundwater controls. This stimulating effect was generally most pronounced for viable counts and could be larger than two orders of magnitude. Leachates from untreated buffer material also stimulated the growth of groundwater bacteria, but to a lesser extent than leachates from heat- and radiation-treated buffer material. The effects of heat and radiation on nutrient availability in clay-based sealing materials should, therefore, be taken into account when attempting to quantify the effects of microbial activity on vault performance.

  1. Shear-wave velocity as an indicator for rheological changes in clay materials: Lessons from laboratory experiments

    NASA Astrophysics Data System (ADS)

    Mainsant, G.; Jongmans, D.; Chambon, G.; Larose, E.; Baillet, L.

    2012-10-01

    Clay-rich geological formations are responsible for many landslides, the dynamics of which are still poorly understood and intensely debated. Analysis of landslide motion shows that slow clayey slope movements can suddenly accelerate and fluidize as a result of sudden loading or heavy rainfall. This solid-fluid transition, which involves disorganization of the particle network, is accompanied by a loss in rigidity that could potentially be monitored by S-wave velocity (Vs) variations. To investigate this hypothesis, two types of laboratory experiments were performed on clay samples originating from an area affected by numerous landslides (Trièves, French Alps). First, creep and oscillatory rheometric tests revealed the thixotropic behavior of the clay with a highly pronounced viscosity bifurcation at a critical stress τc. In relation with this reduction in apparent viscosity, a significant drop in Vs is also observed over τc. Second, at zero stress, acoustic surface wave propagation experiments showed a rapid linear Vs decrease with the gravimetric water content (w) in the plastic domain, and a much lower decay in the liquid domain. The geotechnically-defined liquid limit then appears as a break in the Vs-w curve. For water contents in the liquid domain in particular, both experiments gave consistent results. These laboratory results demonstrate that rheological changes in clay can be revealed through Vs variations, offering the possibility of monitoring solid-to-fluid transitions in the field.

  2. Modeling in Ceramic Clay

    ERIC Educational Resources Information Center

    Miller, Louis J.

    1976-01-01

    Modeling is an additive process of building up a sculpture with some plastic material like clay. It affords the student an opportunity to work in three dimensions, a creative relief from the general two-dimensional drawing and design activities that occupy a large segment of time in the art curriculum. (Author/RK)

  3. Medical rare book provenance.

    PubMed Central

    Overmier, J A; Sentz, L

    1987-01-01

    Provenance is defined as the record of a book's ownership history. Its value and uses are explored. A survey of provenance practices in medical school rare book libraries found that only 21% of the reporting libraries maintain this important file. Examples of the uses and value of a provenance file in a medical rare book collection are presented. Decisions necessary to institute and maintain such a file are outlined and discussed. PMID:3828606

  4. Slag of Greek provenance uses in materials science and geophysics: implications for a highly potential material in the service of the development of Greek economy

    NASA Astrophysics Data System (ADS)

    Leontakianakos, G.; Baziotis, I.; Sotiriadis, K.; Goulas, G.; Liakopoulos, S.; Karastathis, V.

    2012-04-01

    Ground granulated blast-furnace slag (GGBS) is a secondary raw material that can be used as an alternative low energy binder. Hydraulic properties can be occurred through its alkali activation. GGBS is characterized by the glassy to crystalline ratio and by its chemical and mineralogical composition. Acidic slag cannot easily get crystallized in oppose to the basic one. Crystalline phases show very low reactivity with Ca(OH)2, while amorphous phases can easily react in the presence of basic substances. The aim of the present study was to study the evolution of new advanced silicate materials presenting high durability at high temperature environments. Specimens were produced using two types of slag of Greek origin. The first type was a ferrous slag, while the second one was calcareous. Their maximum particle size was 4 mm and 0.07 mm respectively. Specimens were prepared using the above slag types and siliceous sand as an aggregate. Sand was divided according to European Standard EN 196-1 in three fractions: PG1 (1

  5. The systems containing clays and clay minerals from modified drug release: a review.

    PubMed

    Rodrigues, Luís Alberto de Sousa; Figueiras, Ana; Veiga, Francisco; de Freitas, Rivelilson Mendes; Nunes, Lívio César Cunha; da Silva Filho, Edson Cavalcanti; da Silva Leite, Cleide Maria

    2013-03-01

    Clays are materials commonly used in the pharmaceutical industry, either as ingredients or as active ingredients. It was observed that when they are administered concurrently, they may interact with drugs reducing their absorption. Therefore, such interactions can be used to achieve technological and biopharmaceutical advantages, regarding the control of release. This review summarizes bibliographic (articles) and technological (patents) information on the use of systems containing clays and clay minerals in modified drug delivery. In this area, formulations such natural clay, commercial clay, synthetic clay, composites clay-polymers, nanocomposites clay-polymers, films and hidrogels composites clay-polymers are used to slow/extend or vectorize the release of drugs and consequently they increase their bioavailability. Finally, this review summarizes the fields of technology and biopharmaceutical applications, where clays are applied.

  6. Provenance study conflict Miocene eolian deposit in central China

    NASA Astrophysics Data System (ADS)

    Liu, S.; Stockli, D. F.; Li, J.; Song, C.

    2013-12-01

    The dispute of fine-grained Miocene sediments from Tianshui Basin, northeastern Tibetan Plateau as eolian loess-paleosol or neptunian mudflat/distal fan is an unresolved hot topic in Cenozoic palaeoclimatology , impacting further research of Asian monsoon and the mechanism of its variations. Tratigraphic correlation and constraining the sedimentary age with paleomagnetic method show that hundreds miles of foreland basin stratums occurred in north of West Qinling mountain belt in Miocene. The tratums are about 2000 m thick in the south foredeep range, thinning to less than 300 m thick in the north backbulge range. Similar heavy minerals composition and detrital ziron U/Pb ages distribution also show that the materials in the basin were from the same denuded regions. Such evidences conform that the Miocene sedimentary sections identified as loess in Tianshui basin could be distal fan and flood plain in the united foreland basin system. Comprehensive provenance techniques of heavy minerals and detrital zircon U/Pb ages show differences between Miocene Tianshui sediments and Pliocene- Quaternary loess- red clay from Chinese loess Plateau. Specifically, samples from Tianshui basin have more than 20% of Magnetite and 30% of Epidote, but Amphibole is lacking. Loess-red clay samples consist of 21% Amphibole on average. Classifying degree of correction of Amphibole proves that weathering erosion is not the reason for this dissimilarity. More Amphibole rich iginous rocks or matemorphoic rocks could exist widely in loess's source region. Most zircon U/Pb ages in this study fall into similar ranges, especially from 200Ma to 500Ma. There is a significant age peak from 200Ma to 250Ma in Tianshui sediments and modern river sands originating from West Qinling mountain belt, which is rare in loess-red clay samples. A part of zircons from loess and red clay contain very low U and Th elements, implying some of Mafic or intermediate rocks in eolian source area. Both Mafic and

  7. Clay for Little Fingers.

    ERIC Educational Resources Information Center

    Koster, Joan Bouza

    1999-01-01

    Discusses the renewed interest in clay as a modeling compound in early childhood programs; describes the nature of clay and presents a working vocabulary. Suggests methods of working with clay, including introducing clay to children, discovering its uses, clean up, firing clay, and finishing baked clay. Includes activity suggestions and…

  8. Clay-based Nanocomposites Possibilities and Limitations

    NASA Astrophysics Data System (ADS)

    Papoulis, Dimitris

    2011-09-01

    In the last decades, clay mineral based nanocomposites and polymer-clay nanocomposites (PCNC) have been proposed as very useful materials for many uses including photocatalysis, medicinal uses as tissue engineering or modified drug delivery systems. Clay minerals and especially montmorillonite, kaolinite, halloysite palygorskite and sepiolite are the most used clay minerals because of their high surface areas, colloidal dimensions of their particles and other properties. This lecture aims at reporting on very recent developments in the use of clay minerals and PCNC as materials with photocatalytic and medical interest.

  9. Fire clay

    USGS Publications Warehouse

    Virta, R.L.

    2004-01-01

    Seven companies mined fire clay in four states during 2003. From 1984 to 1992, production declined to 383 kt (422,000 st) from a high of 1.04 Mt (1.14 million st) as markets for clay-based refractories declined. Since 1992, production levels have been erratic, ranging from 383 kt (422,000 st) in 1992 and 2001 to 583 kt (642,000 st) in 1995. Production in 2003, based on preliminary data, was estimated to be around 450 kt (496,000 st) with a value of about $10.5 million. This was about the same as in 2002. Missouri remained the leading producer state, followed by South Carolina, Ohio and California.

  10. Contact micromechanics in granular media with clay

    SciTech Connect

    Ita, Stacey Leigh

    1994-08-01

    Many granular materials, including sedimentary rocks and soils, contain clay particles in the pores, grain contacts, or matrix. The amount and location of the clays and fluids can influence the mechanical and hydraulic properties of the granular material. This research investigated the mechanical effects of clay at grain-to-grain contacts in the presence of different fluids. Laboratory seismic wave propagation tests were conducted at ultrasonic frequencies using spherical glass beads coated with Montmorillonite clay (SWy-1) onto which different fluids were adsorbed. For all bead samples, seismic velocity increased and attenuation decreased as the contact stiffnesses increased with increasing stress demonstrating that grain contacts control seismic transmission in poorly consolidated and unconsolidated granular material. Coating the beads with clay added stiffness and introduced viscosity to the mechanical contact properties that increased the velocity and attenuation of the propagating seismic wave. Clay-fluid interactions were studied by allowing the clay coating to absorb water, ethyl alcohol, and hexadecane. Increasing water amounts initially increased seismic attenuation due to clay swelling at the contacts. Attenuation decreased for higher water amounts where the clay exceeded the plastic limit and was forced from the contact areas into the surrounding open pore space during sample consolidation. This work investigates how clay located at grain contacts affects the micromechanical, particularly seismic, behavior of granular materials. The need for this work is shown by a review of the effects of clays on seismic wave propagation, laboratory measurements of attenuation in granular media, and proposed mechanisms for attenuation in granular media.

  11. Provenance in Neuroimaging

    PubMed Central

    MacKenzie-Graham, Allan J.; Van Horn, John D.; Woods, Roger P.; Crawford, Karen L.

    2008-01-01

    Provenance, the description of the history of a set of data, has grown more important with the proliferation of research consortia-related efforts in neuroimaging. Knowledge about the origin and history of an image is crucial for establishing data and results quality; detailed information about how it was processed, including the specific software routines and operating systems that were used, is necessary for proper interpretation, high fidelity replication and re-use. We have drafted a mechanism for describing provenance in a simple and easy to use environment, alleviating the burden of documentation from the user while still providing a rich description of an image’s provenance. This combination of ease of use and highly descriptive metadata should greatly facilitate the collection of provenance and subsequent sharing of data. PMID:18519166

  12. Energy conserving process for calcining clay

    SciTech Connect

    Baird, D.P.

    1990-08-14

    This patent describes an energy conversing process for calcining a clay. It comprises feeding a dry pulverized clay powder as feed material to a calciner to be calcined therein; passing the clay powder to be calcined through the calciner in direct heat exchange contact with a hot calcining gas passing therethrough whereby the clay powder is sufficiently heated to calcine substantially all the clay powder passing through the calciner and the hot calcining has is somewhat cooled; removing the calcined clay powder from the calciner and discharging the calcining from the calciner; subjecting the calciner discharge gas to electrostatic precipitation to clean the calciner discharge gas prior to venting the calciner discharge gas to the atmosphere whereby at least a substantial portion of calcined clay powder entrained in the calciner discharge gas is removed therefrom; collecting the hot calcined clay powder separated from the gas during electrostatic precipitation and mixing the collected hot calcined clay powder with the clay feed material being supplied to the calciner without substantially cooling the collected hot calcined clay powder prior to mixing with the feed material; and passing the calciner discharge has in heat exchange relationship with at least a portion of a cooling fluid prior to subjecting the calciner discharge gas to electrostatic precipitation.

  13. Clay: The Forgotten Art.

    ERIC Educational Resources Information Center

    Martin, Doris Marie

    1995-01-01

    Discusses the tactile and kinesthetic areas of learning children experience when using clay. Includes practical tips for using and storing clay for preschool use and notes the differences between potters' clay and play dough. (HTH)

  14. Clay: The Forgotten Art.

    ERIC Educational Resources Information Center

    Martin, Doris Marie

    1995-01-01

    Discusses the tactile and kinesthetic areas of learning children experience when using clay. Includes practical tips for using and storing clay for preschool use and notes the differences between potters' clay and play dough. (HTH)

  15. Innocent Until Proven Guilty

    ERIC Educational Resources Information Center

    Case, Catherine; Whitaker, Douglas

    2016-01-01

    In the criminal justice system, defendants accused of a crime are presumed innocent until proven guilty. Statistical inference in any context is built on an analogous principle: The null hypothesis--often a hypothesis of "no difference" or "no effect"--is presumed true unless there is sufficient evidence against it. In this…

  16. The provenance of rutile.

    USGS Publications Warehouse

    Force, E.R.

    1980-01-01

    Most coarse detrital rutile is derived from high-grade metamorphic rocks. Contrary to a conventional assumption, independent rutile grains are particularly rare in igneous rocks except alkalic rocks. The use of rutile in the zircon-tourmaline-rutile index of mineralogic maturity is only partially valid, owing to its restricted provenance. -Author

  17. Innocent Until Proven Guilty

    ERIC Educational Resources Information Center

    Case, Catherine; Whitaker, Douglas

    2016-01-01

    In the criminal justice system, defendants accused of a crime are presumed innocent until proven guilty. Statistical inference in any context is built on an analogous principle: The null hypothesis--often a hypothesis of "no difference" or "no effect"--is presumed true unless there is sufficient evidence against it. In this…

  18. Killer clays! Natural antibacterial clay minerals

    USGS Publications Warehouse

    Williams, L.B.; Holland, M.; Eberl, D.D.; Brunet, T.; De Courrsou, L. B.

    2004-01-01

    The clay chemical properties that may be important in medicine were investigated. It was found that natural clay minerals can have striking and very specific effects on microbial populations. The effects can range from potentially enhanced microbial growth to complete sterilization. This paper presents evidence that natural clay minerals can be effective antimicrobial agents.

  19. Green Clay Minerals

    NASA Astrophysics Data System (ADS)

    Velde, B.

    2003-12-01

    part of it is reduced, another is formed. This is the fundamental geochemical aspect of the genesis of green clay minerals; they contain iron in both oxidation states.Unfortunately modern methods of mineral analysis on a microscopic scale, electron microbeam and others, do not allow the determination of the different oxidation states of iron especially for nonstoichiometric minerals. One can use Mössbauer spectral analysis, but the scales of observations are not the same (Mössbauer needing more material); one method used for observations on a microscale, the other on a macroscale. Given the problems of micro- and macroscale observations, oxidation state information is almost excluded from data gathered since the 1980s or so, and hence information concerning the relations of iron reduction and clay genesis must be taken from older studies. A second, much greater problem is that little X-ray diffraction (XRD) work is done on samples which are analyzed chemically by electron microbeam studies. In the past both types of information, structural and chemical, were available for the same sample. Hence not only do we have no precise chemical data for many samples (oxidation state of iron), but there is a rarity of mineral structural information to go along with the incomplete chemistry. This is critical for the study of clay minerals, because slight chemical changes in a clay mineral are frequently accompanied by changes in its structure, especially when one deals with interstratified clay minerals (mica/smectites for example). In fact, the tendency to obtain more and more precision (analysis of a smaller and smaller sized sample) has led to a total loss of mineralogical data. The Heisenberg principle is unwittingly verified by geologists. We know more about a small part of a sample, but we know less about its whole. As a result, the following discussion is based largely upon old data, those which combine iron oxidation states and XRD information.

  20. Wetland eco-engineering: measuring and modeling feedbacks of oxidation processes between plants and clay-rich material

    NASA Astrophysics Data System (ADS)

    Saaltink, Rémon; Dekker, Stefan C.; Griffioen, Jasper; Wassen, Martin J.

    2016-09-01

    Interest is growing in using soft sediment as a foundation in eco-engineering projects. Wetland construction in the Dutch lake Markermeer is an example: here, dredging some of the clay-rich lake-bed sediment and using it to construct wetland will soon begin. Natural processes will be utilized during and after construction to accelerate ecosystem development. Knowing that plants can eco-engineer their environment via positive or negative biogeochemical plant-soil feedbacks, we conducted a 6-month greenhouse experiment to identify the key biogeochemical processes in the mud when Phragmites australis is used as an eco-engineering species. We applied inverse biogeochemical modeling to link observed changes in pore water composition to biogeochemical processes. Two months after transplantation we observed reduced plant growth and shriveling and yellowing of foliage. The N : P ratios of the plant tissue were low, and these were affected not by hampered uptake of N but by enhanced uptake of P. Subsequent analyses revealed high Fe concentrations in the leaves and roots. Sulfate concentrations rose drastically in our experiment due to pyrite oxidation; as reduction of sulfate will decouple Fe-P in reducing conditions, we argue that plant-induced iron toxicity hampered plant growth, forming a negative feedback loop, while simultaneously there was a positive feedback loop, as iron toxicity promotes P mobilization as a result of reduced conditions through root death, thereby stimulating plant growth and regeneration. Given these two feedback mechanisms, we propose the use of Fe-tolerant species rather than species that thrive in N-limited conditions. The results presented in this study demonstrate the importance of studying the biogeochemical properties of the situated sediment and the feedback mechanisms between plant and soil prior to finalizing the design of the eco-engineering project.

  1. Provenance Store Evaluation

    SciTech Connect

    Paulson, Patrick R.; Gibson, Tara D.; Schuchardt, Karen L.; Stephan, Eric G.

    2008-03-01

    Requirements for the provenance store and access API are developed. Existing RDF stores and APIs are evaluated against the requirements and performance benchmarks. The team’s conclusion is to use MySQL as a database backend, with a possible move to Oracle in the near-term future. Both Jena and Sesame’s APIs will be supported, but new code will use the Jena API

  2. Pier-scour depths affected by clay in Mississippi

    USGS Publications Warehouse

    Wilson, K. Van

    1998-01-01

    This paper briefly presents pier-scour depths measured during 1943-94, that are thought to have been affected by consolidated cohesive materials (clay) in Mississippi. MDOT soil reports were available for 29 measured pier-scour depths thought to be affected by clay. The cohesion and friction angles were approximated for the clay, and using the soil borings where clay was overlain by sand and(or) gravel, the top of the clay stratum was approximated in order to determine the net scour through the clay. Eight additional measured pier-scour depths were thought to be affected by clay, but no MDOT soil reports or borings were available. The net pier-scour depth through the clay is a rough approximation where sand and (or) gravel overlie a clay stratum and, therefore, only represents part of the total pier-scour depth. Limited data indicate the pier-scour depth decreases as shear strength of the clay increases.

  3. Imprinted Clay Coil Vessels

    ERIC Educational Resources Information Center

    Lohr, Tresa Rae

    2006-01-01

    The author teaches clay vessel construction in the fifth grade, and it is amazing what can be accomplished in one forty-five minute period when the expectations are clarified in the initial lesson. The author introduces clay coil vessels with a discussion of the sources of clay and how clay relates to fifth-grade science curriculum concepts such…

  4. Imprinted Clay Coil Vessels

    ERIC Educational Resources Information Center

    Lohr, Tresa Rae

    2006-01-01

    The author teaches clay vessel construction in the fifth grade, and it is amazing what can be accomplished in one forty-five minute period when the expectations are clarified in the initial lesson. The author introduces clay coil vessels with a discussion of the sources of clay and how clay relates to fifth-grade science curriculum concepts such…

  5. Initiation and development of slickenlined surfaces in clay-rich material of the Nankai Trough accretionary prism

    NASA Astrophysics Data System (ADS)

    Crespo-Blanc, Ana; Schleicher, Anja

    2016-04-01

    During the International Ocean Discovery Program (IODP) Expedition 348, which is part of the Nankai Trough Seismogenic Zone Experiment (stage 3), the drilling vessel Chikyu advanced the deep riser hole at Site C0002, located 80 km offshore of the Kii Peninsula (Japan), from a depth of 860 meters below sea floor (mbsf) to 3058.5 mbsf. Underlying the Kumano Basin sediments, the Nankai accretionary prism appears, below 975.5 mbsf. It accreted during Upper Miocene to Pliocene times and is formed mainly by turbiditic silty claystone with rarely observed sandstone intercalations. Cuttings from both the 1-4 mm and >4 mm size fractions were investigated, showing slickenlined surfaces and deformation bands together with carbonate veins throughout the entire section from 1045.5 until 3058.5 mbsf. A scaly fabric is increasingly observed below approximately 2400 mbsf. Clay-rich cuttings were selected at different depth for specific SEM-EDS analysis, in order to investigate the initiation and development of the slickenlined surfaces, from both a structural and mineralogical point of view. Two end-members of the slickenlined surface types were observed: a) isolated smooth and uniform planes, between 20 and 50 μm long, formed by single grains of smectite with marked lineations and frequently jagged boundaries and b) microfaults (longer than 100 μm) with sharp boundaries to the undeformed rock, formed by aggregates of illite and smectite and with a well-developed lineation. In transition between these two end-member types, planes that are apparently unconnected draw a single plane and show subparallel lineations. Concerning the orientation of the slickenlines, it seems to be coherent with that observed in an array of conjugated faults, i.e. all the slickenlines belong to the same plane, in turn sub-perpendicular to the intersection of conjugated planes. These observations suggest that the slickenlined surfaces initiated along single grains of smectite and that with increasing

  6. Common clay and shale

    USGS Publications Warehouse

    Virta, R.L.

    2011-01-01

    The article discusses the latest developments in the global common clay and shale industry, particularly in the U.S. It claims that common clay and shale is mainly used in the manufacture of heavy clay products like brick, flue tile and sewer pipe. The main producing states in the U.S. include North Carolina, New York and Oklahoma. Among the firms that manufacture clay and shale-based products are Mid America Brick & Structural Clay Products LLC and Boral USA.

  7. Semantic Workflows and Provenance

    NASA Astrophysics Data System (ADS)

    Gil, Y.

    2011-12-01

    While sharing and disseminating data is widely practiced across scientific communities, we have yet to recognize the importance of sharing and disseminating the analytic processes that leads to published data. Data retrieved from shared repositories and archives is often hard to interpret because we lack documentation about those processes: what models were used, what assumptions were made, what calibrations were carried out, etc. This process documentation is also key to aggregate data in a meaningful way, whether aggregating shared third party data or aggregating shared data with local sensor data collected by individual investigators. We suggest that augmenting published data with process documentation would greatly enhance our ability to find, reuse, interpret, and aggregate data and therefore have a significant impact in the utility of data repositories and archives. We will show that semantic workflows and provenance provide key technologies for capturing process documentation. Semantic workflows describe the kinds of data transformation and analysis steps used to create new data products, and can include useful constraints about why specific models were selected or parameters chosen. Provenance records can be used to publish workflow descriptions in standard formats that can be reused to enable verification and reproducibility of data products.

  8. Cell line provenance.

    PubMed

    Freshney, R Ian

    2002-07-01

    Cultured cell lines have become an extremely valuable resource, both in academic research and in industrial biotechnology. However, their value is frequently compromised by misidentification and undetected microbial contamination. As detailed elsewhere in this volume, the technology, both simple and sophisticated, is available to remedy the problems of misidentification and contamination, given the will to apply it. Combined with proper records of the origin and history of the cell line, assays for authentication and contamination contribute to the provenance of the cell line. Detailed records should start from the initiation or receipt of the cell line, and should incorporate data on the donor as well as the tissue from which the cell line was derived, should continue with details of maintenance, and include any accidental as well as deliberate deviations from normal maintenance. Records should also contain details of authentication and regular checks for contamination. With this information, preferably stored in a database, and suitable backed up, the provenance of the cell line so created makes the cell line a much more valuable resource, fit for validation in industrial applications and more likely to provide reproducible experimental results when disseminated for research in other laboratories.

  9. Clay at Nili Fossae

    NASA Technical Reports Server (NTRS)

    2006-01-01

    at the upper right, the small mesa -- a flat-topped hill -- at the center of the image is a remnant of an overlying rock layer that was eroded away. The greenish clay areas at the base of the hill were exposed by erosion of the overlying rock. The images at the upper right and lower left both show that the reddish-toned olivine occurs as sand dunes on top of the greenish clay deposits. The image at the lower right shows details of the clay-rich rock, including that they are extensively fractured into small, polygonal blocks just a few meters in size. Taken together, the CRISM and HiRISE data show that the clay-rich rocks are the oldest at the site, that they are exposed where overlying rock has been eroded away, and that the olivine is not part of the clay-rich rock. Rather it occurs in sand dunes blowing across the clay.

    Many more images of Nili Fossae and other clay-rich areas will be taken over the next two years. They will be used to try to understand the earliest climate of Mars that is recorded in the planet's rocks.

    The Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) is one of six science instruments on NASA's Mars Reconnaissance Orbiter. Led by The Johns Hopkins University Applied Physics Laboratory, the CRISM team includes expertise from universities, government agencies and small businesses in the United States and abroad.

    CRISM's mission: Find the spectral fingerprints of aqueous and hydrothermal deposits and map the geology, composition and stratigraphy of surface features. The instrument will also watch the seasonal variations in Martian dust and ice aerosols, and water content in surface materials o leading to new understanding of the climate.

    NASA's Jet Propulsion Laboratory, a division of the Califonia Institute of Technology, Pasadena, manages the Mars Reconnaissance Orbiter for the NASA Science Mission Directorate, Washington. Lockheed Martin Space Systems, Denver, is the prime contractor and built the spacecraft.

  10. Clay at Nili Fossae

    NASA Technical Reports Server (NTRS)

    2006-01-01

    at the upper right, the small mesa -- a flat-topped hill -- at the center of the image is a remnant of an overlying rock layer that was eroded away. The greenish clay areas at the base of the hill were exposed by erosion of the overlying rock. The images at the upper right and lower left both show that the reddish-toned olivine occurs as sand dunes on top of the greenish clay deposits. The image at the lower right shows details of the clay-rich rock, including that they are extensively fractured into small, polygonal blocks just a few meters in size. Taken together, the CRISM and HiRISE data show that the clay-rich rocks are the oldest at the site, that they are exposed where overlying rock has been eroded away, and that the olivine is not part of the clay-rich rock. Rather it occurs in sand dunes blowing across the clay.

    Many more images of Nili Fossae and other clay-rich areas will be taken over the next two years. They will be used to try to understand the earliest climate of Mars that is recorded in the planet's rocks.

    The Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) is one of six science instruments on NASA's Mars Reconnaissance Orbiter. Led by The Johns Hopkins University Applied Physics Laboratory, the CRISM team includes expertise from universities, government agencies and small businesses in the United States and abroad.

    CRISM's mission: Find the spectral fingerprints of aqueous and hydrothermal deposits and map the geology, composition and stratigraphy of surface features. The instrument will also watch the seasonal variations in Martian dust and ice aerosols, and water content in surface materials o leading to new understanding of the climate.

    NASA's Jet Propulsion Laboratory, a division of the Califonia Institute of Technology, Pasadena, manages the Mars Reconnaissance Orbiter for the NASA Science Mission Directorate, Washington. Lockheed Martin Space Systems, Denver, is the prime contractor and built the spacecraft.

  11. The colloidal chemistry of ceramic clays

    NASA Technical Reports Server (NTRS)

    Phelps, G. W.

    1984-01-01

    The colloidal chemistry and mineralogy of two argil minerals were studied. Deposits of kaolin and of ceramic clays in the United States and England are discussed for the probable mechanism of formation. The structural modifications of the bed, original material associated with the clays and the proper use of flocculants are discussed.

  12. Dehydration-induced luminescence in clay minerals

    NASA Technical Reports Server (NTRS)

    Coyne, L. M.; Lahav, N.; Lawless, J. G.

    1981-01-01

    Reports of triboluminescent phenomena in organic crystalline materials prompted a search for related processes in clay minerals. The reported extensive mechanical distortion produced on freezing and drying of montmorillonite was particularly interesting because of studies of condensation reactions in a wet/dry cycled reaction sequence. The discovery of an unusual luminescent process in several clay minerals is reported and its characteristics are described.

  13. Dehydration-induced luminescence in clay minerals

    NASA Technical Reports Server (NTRS)

    Coyne, L. M.; Lahav, N.; Lawless, J. G.

    1981-01-01

    Reports of triboluminescent phenomena in organic crystalline materials prompted a search for related processes in clay minerals. The reported extensive mechanical distortion produced on freezing and drying of montmorillonite was particularly interesting because of studies of condensation reactions in a wet/dry cycled reaction sequence. The discovery of an unusual luminescent process in several clay minerals is reported and its characteristics are described.

  14. Biodegradable Pectin/clay Aerogels

    USDA-ARS?s Scientific Manuscript database

    Biodegradable, foamlike materials based on renewable pectin and sodium montmorillonite clay were fabricated through a simple, environmentally friendly freeze-drying process. Addition of multivalent cations (Ca2+ and Al3+) resulted in apparent crosslinking of the polymer, and enhancement of aerogel p...

  15. Design and characterization of a composite material based on Sr(II)-loaded clay nanotubes included within a biopolymer matrix.

    PubMed

    Del Buffa, Stefano; Bonini, Massimo; Ridi, Francesca; Severi, Mirko; Losi, Paola; Volpi, Silvia; Al Kayal, Tamer; Soldani, Giorgio; Baglioni, Piero

    2015-06-15

    This paper reports on the preparation, characterization, and cytotoxicity of a hybrid nanocomposite material made of Sr(II)-loaded Halloysite nanotubes included within a biopolymer (3-polyhydroxybutyrate-co-3-hydroxyvalerate) matrix. The Sr(II)-loaded inorganic scaffold is intended to provide mechanical resistance, multi-scale porosity, and to favor the in-situ regeneration of bone tissue thanks to its biocompatibility and bioactivity. The interaction of the hybrid system with the physiological environment is mediated by the biopolymer coating, which acts as a binder, as well as a diffusional barrier to the Sr(II) release. The degradation of the polymer progressively leads to the exposure of the Sr(II)-loaded Halloysite scaffold, tuning its interaction with osteogenic cells. The in vitro biocompatibility of the composite was demonstrated by cytotoxicity tests on L929 fibroblast cells. The results indicate that this composite material could be of interest for multiple strategies in the field of bone tissue engineering. Copyright © 2015 Elsevier Inc. All rights reserved.

  16. Clay minerals for advanced ceramics

    SciTech Connect

    Murray, H.H. )

    1989-11-01

    The author describes new and improved beneficiation techniques available to allow the production of clay minerals of exceptionally high purity. This is particularly true for kaolins and smectites. Wet processing techniques include particle size separation, high intensity magnetic separation, chemical leaching, flotation, and selective flocculation. The blending of clay minerals with other minerals provides opportunities to make special ceramic materials such as cordierite and other minerals that have very special ceramic properties including low heat expansion, high fired strength, low absorption, and other desired qualities.

  17. Surface Geochemistry of the Clay Minerals

    NASA Astrophysics Data System (ADS)

    Sposito, Garrison; Skipper, Neal T.; Sutton, Rebecca; Park, Sung-Ho; Soper, Alan K.; Greathouse, Jeffery A.

    1999-03-01

    Clay minerals are layer type aluminosilicates that figure in terrestrial biogeochemical cycles, in the buffering capacity of the oceans, and in the containment of toxic waste materials. They are also used as lubricants in petroleum extraction and as industrial catalysts for the synthesis of many organic compounds. These applications derive fundamentally from the colloidal size and permanent structural charge of clay mineral particles, which endow them with significant surface reactivity. Unraveling the surface geochemistry of hydrated clay minerals is an abiding, if difficult, topic in earth sciences research. Recent experimental and computational studies that take advantage of new methodologies and basic insights derived from the study of concentrated ionic solutions have begun to clarify the structure of electrical double layers formed on hydrated clay mineral surfaces, particularly those in the interlayer region of swelling 2:1 layer type clay minerals. One emerging trend is that the coordination of interlayer cations with water molecules and clay mineral surface oxygens is governed largely by cation size and charge, similarly to a concentrated ionic solution, but the location of structural charge within a clay layer and the existence of hydrophobic patches on its surface provide important modulations. The larger the interlayer cation, the greater the influence of clay mineral structure and hydrophobicity on the configurations of adsorbed water molecules. This picture extends readily to hydrophobic molecules adsorbed within an interlayer region, with important implications for clay-hydrocarbon interactions and the design of catalysts for organic synthesis.

  18. Provenance and flux of detrital materials in Lake Suigetsu sediment (SG12 core) and their temporal changes during the last 20 kyrs based on color and XRF data

    NASA Astrophysics Data System (ADS)

    Suzuki, Y.; Tada, R.; Nakagawa, T.; Gotanda, K.; Haraguchi, T.; Nagashima, K.; Irino, T.; Sugisaki, S.; Kojima, H.; Horiuchi, D.

    2013-12-01

    Lake Suigetsu in Central Japan is known for its annual lamination (varve) starting from 70kys ago. Extremely precise Age-depth model is established for SG06 core based on over 800 14C dates obtained on terrestrial leaf fossils and wiggle-matched to stalagmite 14C records constrained by varve counts (Staff et al., 2013). By projecting this age model to newly drilled core from the same site, we can obtain precisely age-controlled high resolution paleoenvironmental record around the Lake Suigetsu drainage. It is likely that detrital materials in Lake Suigetsu sediments have several different sources such as soil on the slopes around the lake itself, aeolian dust from inland Asia, and suspended particles supplied from Hasu river through lake Mikata, which is located immediately upstream of Lake Suigetsu and trapping most of coarse detrital grains. However, the relative contribution from each detrital source and its temporal changes are poorly known. The lack of knowledge on relative contribution of different detrital sources limits utility of detrital materials as proxies of paleo-environments. In this study, we are aiming to reconstruct the history of precipitation changes in the drainage area of Lake Suigetsu during the Holocene to explore the relationship between precipitation in the Japan Sea side of SW Japan, behavior of Asian monsoon system as an important component of the global climate system. It is well known that flux of suspended particles in rivers increases with precipitation. In order for us to be able to use the Hasu river's flux of suspended particles as the precipitation proxy, however, we first need to establish a simple and swift way to estimate the contribution of detrital materials from Hasu River flowing through Lake Mikata into Lake Suigetsu. We carried out color measurement with 5mm resolution on split half core surface of the sediment drilled in the summer of 2012(SG12), and compared these values to chemical composition data by XRF microscanner

  19. Photochemistry on, and Nature of Adsorbed Species on Colloidal Clay and Model Clay Systems.

    DTIC Science & Technology

    1987-09-25

    model system for clays, and also acts as a bridge between ionic organic micelle systems and colloidal clays. In the first instance a commercial...hexadecylpyridinium chloride, tend to cluster on the silica surface rather than disperse uniformly around it as with ionic micelles. We have also...alcohol as additives to the clay. Layers of organic material are formed by these additives in montmorillonite layers, and now non- ionic organic

  20. Communicating with Clay.

    ERIC Educational Resources Information Center

    Skophammer, Karen

    2000-01-01

    Presents a unit on clay that is centered around sign language in which students explore the slab method of working with clay. States that each student picks a letter of the sign language alphabet and fashions a clay hand to depict the letter. (CMK)

  1. Basaltic island sand provenance

    SciTech Connect

    Marsaglia, K.M. . Dept. of Geological Sciences)

    1992-01-01

    The Hawaiian Islands are an ideal location to study basaltic sand provenance in that they are a series of progressively older basaltic shield volcanoes with arid to humid microclimates. Sixty-two sand samples were collected from beaches on the islands of Hawaii, Maui, Oahu and Kauai and petrographically analyzed. The major sand components are calcareous bioclasts, volcanic lithic fragments, and monomineralic grains of dense minerals and plagioclase. Proportions of these components vary from island to island, with bioclastic end members being more prevalent on older islands exhibiting well-developed fringing reef systems and volcanic end members more prevalent on younger, volcanically active islands. Climatic variations across the island of Hawaii are reflected in the percentage of weathered detritus, which is greater on the wetter, northern side of the island. The groundmass of glassy, basaltic lithics is predominantly black tachylite, with lesser brown sideromelane; microlitic and lathwork textures are more common than holohyaline vitric textures. Other common basaltic volcanic lithic fragments are holocrystalline aggregates of silt-sized pyroxene or olivine, opaque minerals and plagioclase. Sands derived from alkalic lavas are texturally and compositionally indistinguishable from sands derived from tholeiitic lavas. Although Hawaiian basaltic sands overlap in composition with magmatic arc-derived sands in terms of their relative QFL, QmPK and LmLvLs percentages, they are dissimilar in that they lack felsic components and are more enriched in lathwork volcanic lithic fragments, holocrystalline volcanic lithic fragments, and dense minerals.

  2. Intercalated layered clay composites and their applications

    NASA Astrophysics Data System (ADS)

    Phukan, Anjali

    Supported inorganic reagents are rapidly emerging as new and environmentally acceptable reagents and catalysts. The smectite group of layered clay minerals, such as, Montmorillonite, provides promising character for adsorption, catalytic activity, supports etc. for their large surface area, swelling behavior and ion exchange properties. Aromatic compounds intercalated in layered clays are useful in optical molecular devices. Clay is a unique material for adsorption of heavy metals and various toxic substances. Clay surfaces are known to be catalytically active due to their surface acidity. Acid activated clays possess much improved surface areas and acidities and have higher pore volumes so that can absorb large molecules in the pores. The exchangeable cations in clay minerals play a key role in controlling surface acidity and catalytic activity. Recently, optically active metal-complex-Montmorillonite composites are reported to be active in antiracemization purposes. In view of the above, a research work, relating to the preparation of different modified clay composites and their catalytic applications were carried out. The different aspects and results of the present work have been reported in four major chapters. Chapter I: This is an introductory chapter, which contains a review of the literature regarding clay-based materials. Clay minerals are phyllosilicates with layer structure. Montmorillonite, a member of smectite group of clay, is 2:1 phyllosilicate, where a layer is composed of an octahedral sheet sandwiched by two tetrahedral sheets. Such clay shows cation exchange capacity (CEC) and is expressed in milli-equivalents per 100 gm of dry clay. Clays can be modified by interaction with metal ion, metal complexes, metal cluster and organic cations for various applications. Clays are also modified by treating with acid followed by impregnation with metal salts or ions. Montmorillonite can intercalate suitable metal complexes in excess of CEC to form double

  3. Provenance and fate of organic carbon in three submarine canyons from the Portuguese Margin: Implications for transport processes of material in continental margins

    NASA Astrophysics Data System (ADS)

    Kiriakoulakis, Kostas; Wolff, George; Blackbird, Sabena

    2010-05-01

    Submarine canyons are key environments on the continental margin that are affected by unique and dynamic but often episodic and complex processes, and are difficult to study. Canyons are considered hotspots of biodiversity and enhancement of primary productivity at canyon heads has often been postulated to support this, although the evidence is sparse. Additionally canyons are considered to be fast-track corridors for material transported from the land to the deep sea and they are considered major pathways for the transportation and burial of organic carbon, acting as buffers for sediment and carbon storage. Organic geochemical and isotopic markers are often used as reliable indicators for the supply, quality and fate of organic matter in marine systems. In this study they have been used to test the above hypotheses in three contrasting submarine canyons (Nazaré, Setubal/Lisbon and Cascais) of the Portuguese Margin. The elemental and lipid biomarker composition of suspended particulate organic matter of surface waters close to the studied canyon heads had a fresh phytoplankton signal, however there was no clear evidence for enhanced primary productivity by comparison to the neighbouring open slope. By contrast, mid-depth waters (700-1600 m), that are dominated by the northward flowing Mediterranean Outflow Water, had high lipid content and abundant mesozooplankton biomarkers, perhaps reflecting zooplankton activity focused at the boundaries of distinct water masses. In the waters close to the floor of the Nazaré Canyon the presence of elemental sulphur (a product of sediment diagenesis) and high molecular weight hydrocarbons (recalcitrant, terrestrial markers) indicated high levels of resuspended material, particularly at the Upper section (

  4. Alumina clay compositions

    SciTech Connect

    Holmgren, J.S.; Gembicki, S.A.; Schoonover, M.W.; Kocal, J.A.

    1992-05-19

    This patent describes a composition consisting essentially of a layered clay homogeneously dispersed in an inorganic oxide matrix, such that the clay layers are completely surrounded by the inorganic oxide matrix, the inorganic oxide selected from the group consisting of alumina, titania, silica, zirconia, P{sub 2}O{sub 5} and mixtures thereof. This patent also describes a process of preparing a composition consisting essentially of a layered clay homogeneously dispersed in an inorganic oxide matrix, the process comprising mixing a clay with a hydrosol of a precursor of the inorganic oxide, forming spherical particles from the clay containing hydrosol and calcining the particles to form a composition comprising a clay homogeneously dispersed in an inorganic oxide matrix, such that the clay layers are completely surrounded by the inorganic oxide matrix.

  5. Clays in prebiological chemistry

    NASA Technical Reports Server (NTRS)

    Rao, M.; Oro, J.; Odom, D. G.

    1980-01-01

    The ways in which clays have been utilized in studies of prebiological chemistry are reviewed, and an assessment is given of the possible role of clays in prebiological systems. The adsorption of organic molecules on clays has been demonstrated, as has the synthesis of bioorganic monomers in the presence of clays. For instance, amino acids, purines and pyrimidines have been obtained from carbon monoxide and nitric acid in the presence of clays at relatively high temperatures (250-325 C). The oligomerization of biochemical monomers, mediated by clays, has also been shown to result in the formation of polymer molecules basic to life. Clays have also been found to affect the condensation of mononucleotides to oligonucleotides.

  6. Provenance of the K/T boundary layers

    NASA Technical Reports Server (NTRS)

    Hildebrand, A. R.; Boynton, W. V.

    1988-01-01

    An array of chemical, physical and isotopic evidence indicates that an impact into oceanic crust terminated the Cretaceous Period. Approximately 1500 cu km of debris, dispersed by the impact fireball, fell out globally in marine and nonmarine environments producing a 2 to 4 mm thick layer (fireball layer). In North American locales, the fireball layer overlies a 15 to 25 mm thick layer of similar but distinct composition. This 15 to 25 mm layer (ejecta layer) may represent approximately 1000 cu km of lower energy ejecta from a nearby impact site. Isotopic and chemical evidence supports a mantle provenance for the bulk of the layers. The extraordinary REE pattern of the boundary clays was modelled as a mixture of oceanic crust, mantle, and approximately 10 percent continental material. The results are presented. If the siderophiles of the ejecta layer were derived solely from the mantle, a test may be available to see if the siderophile element anomaly of the fireball layer had an extraterrestrial origin. Radiogenic Os-187 is depleted in the mantle relative to an undifferentiated chondritic source. Os-187/Os-186 ratios of 1.049 and 1.108 were calculated for the ejecta and fireball layers, respectively.

  7. Structural clay tile component behavior

    SciTech Connect

    Columber, Christopher Eugene

    1994-12-18

    The basic properties of structural clay tile walls were determined through component and composite testing of structural clay tile and mortar. The fundamental material parameters and strengths of clay tile coupons were determined through compression, tension, modulus of rupture and absorption tests. Mortar cylinders were tested in both compression and split cylinder fashion. Stress-strain curves for mortar under compression were determined. Four miniature prisms were tested in compression. These prisms were made from two 8 inches x 12 inches x 12 inches structural clay tiles, using a stack bond with a 3/4 inches mortar joint. Stress strain curves as well as material property values were obtained. These results were compared with previous tests on larger (2 feet x 4 feet) prisms. Twenty five bond wrench samples were tested. Two series of bond wrench samples were run. The first series (six tests) were fitted with LVDTs so that load deflection curves as well as flexural strengths could be obtained. A shifting of the neutral axis towards the compression face was observed. The second series were made with different mortar types: type N masonry cement mortar, type S masonry cement mortar, type N portland cement lime (PCL) mortar, and type S PCL mortar. Type S mortar and portland cement lime mortar were found to improve the bond strength.

  8. Provenance through Time

    NASA Astrophysics Data System (ADS)

    Chandler, C. L.; Groman, R. C.; Shepherd, A.; Allison, M. D.; Kinkade, D.; Rauch, S.; Wiebe, P. H.; Glover, D. M.

    2014-12-01

    The ability to reproduce scientific results is a cornerstone of the scientific method, and access to the data upon which the results are based is essential to reproducibility. Access to the data alone is not enough though, and research communities have recognized the importance of metadata (data documentation) to enable discovery and data access, and facilitate interpretation and accurate reuse. The Biological and Chemical Oceanography Data Management Office (BCO-DMO) was first funded in late 2006 by the National Science Foundation (NSF) Division of Ocean Sciences (OCE) Biology and Chemistry Sections to help ensure that data generated during NSF OCE funded research would be preserved and available for future use. The BCO-DMO was formed by combining the formerly independent data management offices of two marine research programs: the United States Joint Global Ocean Flux Study (US JGOFS) and the US GLOBal Ocean ECosystems Dynamics (US GLOBEC) program. Since the US JGOFS and US GLOBEC programs were both active (1990s) there have been significant changes in all aspects of the research data life cycle, and the staff at BCO-DMO has modified the way in which we manage data contributed to the office. The supporting documentation that describes each dataset was originally displayed as a human-readable text file retrievable via a Web browser. BCO-DMO still offers that form because our primary audience is marine researchers using Web browser clients; however we are seeing an increased demand to support machine client access. Metadata records from the BCO-DMO data system are now extracted and published out in a variety of formats. The system supports ISO 19115, FGDC, GCMD DIF, schema.org Dataset extension, formal publication with a DOI, and RDF with semantic markup including PROV-O, FOAF and more. In the 1990s, data documentation helped researchers locate data of interest and understand the provenance sufficiently to determine fitness for purpose. Today, providing data

  9. Permeation properties of polymer/clay nanocomposites

    NASA Astrophysics Data System (ADS)

    Kalendova, A.; Merinska, D.; Gerard, J. F.

    2012-07-01

    The important characteristics of polymer/clay nanocomposites are stability, barrier properties and in the case of polyvinyl chloride also plasticizer migration into other materials. Therefore, the permeation properties of polymer/clay nanocomposites are discussed in this paper. The attention was focused to the polyethylene (PE) and polyvinyl chloride (PVC). Natural type of montmorillonite MMTNa+ and modified types of montmorillonite from Southern Clay Products were used as the inorganic phase. As the compounding machine, one screw Buss KO-kneader was employed. The principal aim is to fully exfoliate the clay into polymer matrix and enhanced the permeation properties. Prepared samples were tested for O2 and CO2 permeability. Polymer/clay nanocomposite structure was determined on the base of X-ray diffraction and electron microscopy (TEM).

  10. Modelling of the physico-chemical behaviour of clay minerals with a thermo-kinetic model taking into account particles morphology in compacted material.

    NASA Astrophysics Data System (ADS)

    Sali, D.; Fritz, B.; Clément, C.; Michau, N.

    2003-04-01

    Modelling of fluid-mineral interactions is largely used in Earth Sciences studies to better understand the involved physicochemical processes and their long-term effect on the materials behaviour. Numerical models simplify the processes but try to preserve their main characteristics. Therefore the modelling results strongly depend on the data quality describing initial physicochemical conditions for rock materials, fluids and gases, and on the realistic way of processes representations. The current geo-chemical models do not well take into account rock porosity and permeability and the particle morphology of clay minerals. In compacted materials like those considered as barriers in waste repositories, low permeability rocks like mudstones or compacted powders will be used : they contain mainly fine particles and the geochemical models used for predicting their interactions with fluids tend to misjudge their surface areas, which are fundamental parameters in kinetic modelling. The purpose of this study was to improve how to take into account the particles morphology in the thermo-kinetic code KINDIS and the reactive transport code KIRMAT. A new function was integrated in these codes, considering the reaction surface area as a volume depending parameter and the calculated evolution of the mass balance in the system was coupled with the evolution of reactive surface areas. We made application exercises for numerical validation of these new versions of the codes and the results were compared with those of the pre-existing thermo-kinetic code KINDIS. Several points are highlighted. Taking into account reactive surface area evolution during simulation modifies the predicted mass transfers related to fluid-minerals interactions. Different secondary mineral phases are also observed during modelling. The evolution of the reactive surface parameter helps to solve the competition effects between different phases present in the system which are all able to fix the chemical

  11. Information Provenance in Social Media

    NASA Astrophysics Data System (ADS)

    Barbier, Geoffrey; Liu, Huan

    Information appearing in social media provides a challenge for determining the provenance of the information. However, the same characteristics that make the social media environment challenging provide unique and untapped opportunities for solving the information provenance problem for social media. Current approaches for tracking provenance information do not scale for social media and consequently there is a gap in provenance methodologies and technologies providing exciting research opportunities for computer scientists and sociologists. This paper introduces a theoretical approach aimed guiding future efforts to realize a provenance capability for social media that is not available today. The guiding vision is the use of social media information itself to realize a useful amount provenance data for information in social media.

  12. Geochemical signatures of bedded cherts of the upper La Luna Formation in Táchira State, western Venezuela: Assessing material provenance and paleodepositional setting

    NASA Astrophysics Data System (ADS)

    Garbán, G.; Martínez, M.; Márquez, G.; Rey, O.; Escobar, M.; Esquinas, N.

    2017-01-01

    Here we undertook an inorganic geochemical study of Cenomanian-Campanian bedded cherts (the Táchira Ftanita Member of the La Luna Formation) in the western region of the Táchira State, Venezuela. The aim of this study was to determine the paleo-oceanographic and paleo-environmental conditions that governed the deposition of chert beds and put forward a sedimentation model for the Táchira Ftanita Member in the study area. Seventy-two chert samples were collected and trace/rare earth elements (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Rb, Cs, Th, U, Y, Co, and Sc) and major/trace elements (SiO2, TiO2, Al2O3, Fe2O3, MgO, CaO, Na2O, K2O, P2O5, Mn, Ba, Sr, Cr, Ni, and V) were determined by ICP-MS and ICP-OES, respectively. On the basis of the stratigraphic abundance and distribution of relatively immobile elements, as well as the distribution of rare earth elements, we established that the detrital sediments associated with the sequences studied have matching characteristics with distinct continental materials, with an intermediate composition, thus pointing to the Guayana Massif as the main source of sediments. In addition, we also determined the influence of hydrothermal input on the chemical composition of some cherts from La Molina Mine. On the basis of geochemistry, we found a biological influence regarding the uptake of dissolved silica for forming chert beds. The application of parameters for relatively immobile elements allowed us to establish a still proximal continental-margin (hemipelagic) for most samples from the Zorca River and a continental-margin for almost all the cherts from the Delicias-Villa Páez section and the remaining samples from La Molina Mine. Finally, we propose that the rhythmicity that accompanies the sequence of bedded cherts is related to changes in the intensity of upwelling patterns of water and/or to variability in the supply of silica dissolved in the Táchira sub-basin.

  13. Surface geochemistry of the clay minerals

    PubMed Central

    Sposito, Garrison; Skipper, Neal T.; Sutton, Rebecca; Park, Sung-ho; Soper, Alan K.; Greathouse, Jeffery A.

    1999-01-01

    Clay minerals are layer type aluminosilicates that figure in terrestrial biogeochemical cycles, in the buffering capacity of the oceans, and in the containment of toxic waste materials. They are also used as lubricants in petroleum extraction and as industrial catalysts for the synthesis of many organic compounds. These applications derive fundamentally from the colloidal size and permanent structural charge of clay mineral particles, which endow them with significant surface reactivity. Unraveling the surface geochemistry of hydrated clay minerals is an abiding, if difficult, topic in earth sciences research. Recent experimental and computational studies that take advantage of new methodologies and basic insights derived from the study of concentrated ionic solutions have begun to clarify the structure of electrical double layers formed on hydrated clay mineral surfaces, particularly those in the interlayer region of swelling 2:1 layer type clay minerals. One emerging trend is that the coordination of interlayer cations with water molecules and clay mineral surface oxygens is governed largely by cation size and charge, similarly to a concentrated ionic solution, but the location of structural charge within a clay layer and the existence of hydrophobic patches on its surface provide important modulations. The larger the interlayer cation, the greater the influence of clay mineral structure and hydrophobicity on the configurations of adsorbed water molecules. This picture extends readily to hydrophobic molecules adsorbed within an interlayer region, with important implications for clay–hydrocarbon interactions and the design of catalysts for organic synthesis. PMID:10097044

  14. Obsidian provenance research in the Americas.

    PubMed

    Glascock, Michael D

    2002-08-01

    The characterization of archaeological materials to support provenance research has grown rapidly over the past few decades. Volcanic obsidian has several unique properties that make it the ideal archaeological material for studying prehistoric trade and exchange. This Account describes our laboratory's development of a systematic methodology for the characterization of obsidian sources and artifacts from Mesoamerica and other regions of North and South America in support of archaeological research.

  15. Dust provenance change of Chinese Loess Plateau during the past 7Ma

    NASA Astrophysics Data System (ADS)

    Zhang, Hanzhi

    2017-04-01

    Aeolian deposit (e.g. loess, paleo-soil and Red Clay) in Chinese Loess Plateau is one of the most valuable climate archives on land in late Cenozoic. Surveying the origin of these aeolian sediments is essential for the interpretation of the climate proxies potentially over the past 25Ma. However, disputes still exist on whether or not there is shift of dust origin in tectonic time scale or glacial-interglacial time scale. Detrital zircon dating method is applied on aeolian sediments of Lantian site in south part of Chinese Loess Plateau, which is at the foot of Qinling Mountain in order to reveal the provenance evolution during the past 7Ma. The results indicate that the composition of aeolian sediments shifted at around 2.6 Ma. Detrital zircon age reveals that the tertiary Red Clay is mainly derived from the North Tibet Plateau and Qinling Mountain. This indicates that the origin area for the tertiary Red Clay is relative local. Quaternary Loess of this site is basically mixture of sediments from North Tibet Plateau and Gobi Altay Mountains. The composition of local sediments from Qinling Mountains is relatively low. Sediment in L1 layer contains the highest proportions of Gobi Altay Mountains material, which show completely different pattern from other loess sediments. Besides this, there are no consistent composition shifts between glacial and interglacial periods. The time of dust origin shift is in coincident with initiation of the Northern Hemisphere ice sheet. This suggests that the onset of the Northern Hemisphere ice sheet enhanced the surface erosion of the area of Gobi Altay Mountains. This process contributed more detrital material to be blown to the air. Furthermore, enhanced winter monsoon played an important role in the transportation of dust material. However, the reason for the unique characteristics of loess in L1 is not clear.

  16. The altarpieces of Della Robbia atelier in Marche region: investigations on technology and provenance

    NASA Astrophysics Data System (ADS)

    Amadori, M. L.; Barcelli, S.; Barcaioni, S.; Bouquillon, A.; Padeletti, G.; Pallante, P.

    2013-12-01

    Dissemination of Della Robbia glazed terracotta in the Marche (Italy) region started from the third decade of the 16th century. Numerous altarpieces, some of which no longer exist, document this artistic production. The protagonists of this diffusion phase were two of Andrea Della Robbia's sons, Marco (Fra Mattia) and Francesco (Fra Ambrogio). This paper shows the results of the scientific investigations carried out on constitutive materials of different altarpieces located in South Marche belonging to the Fra Mattia's production: the Coronation of Virgin between Saints Rocco, Sebastian, Peter martyr and Antonio abbot, dated back to 1527-1530, located in the collegiate church of S. Maria Assunta in Montecassiano; the Annunciation, dated back to 1520, placed in the church of S. Maria del Soccorso in Arcevia; the fragmentary Crowned Madonna and saints altarpiece, probably realized after 1531, today preserved in Civic Museum of Ripatransone. The first altarpiece was made in Montecassiano using two different assembling or production techniques: the external part of the lunette and the pillar strips are made of glazed polychrome terracotta, while the altar step and the internal part are an interesting and uncommon example of polychrome painted terracotta. The provenance of the glazed Arcevia altarpiece is not clear yet: some historians hypothesize a local manufacture of Fra Mattia and some others a Roman or Florentine production. The remaining parts of Ripatransone altarpiece are partially glazed and partially not coated perhaps because they were unfinished and not yet painted. Clay body samples collected from the above mentioned altarpieces were investigated using different analytical techniques (OM, XRD, XRF, PIXE) to point out differences in chemical and mineralogical composition and to determine if the altarpieces were made by using local raw clay materials or other clays from Tuscany or Campania as in the Della Robbia previous production. A comparison has also been

  17. Incorporating Zataria multiflora Boiss. essential oil and sodium bentonite nano-clay open a new perspective to use zein films as bioactive packaging materials.

    PubMed

    Kashiri, Mahboobeh; Maghsoudlo, Yahya; Khomeiri, Morteza

    2017-10-01

    Active zein films with different levels of Zataria multiflora Boiss. essential oil were produced successfully. To enhance properties of this biopolymer for food packaging applications, sodium bentonite clay was used at two levels (2 and 4%). The results indicated that the addition of Z. multiflora Boiss. essential oil caused a reduction in tensile strength and Young's modulus and slight increase in the percent of elongation at break of the films. Maximum solubility in water and water vapor permeability was observed by incorporation of 10% Z. multiflora Boiss. essential oil in the zein matrix. Transmission electron microscopy micrographs of zein film were verified by the exfoliation of the layers of sodium bentonite clay in the zein matrix. Stronger films with lower water vapor permeability and water solubility were evident of good distribution of sodium bentonite clay in the zein matrix. According to the results, 2% sodium bentonite clay was selected for evaluation of nano active film properties. Water vapor permeability, UV light barrier, tensile strength, and Young's modulus values of active films were improved by incorporation of 2% sodium bentonite clay. The antibacterial activity of different contents of Z. multiflora Boiss. essential oil in vapor phase demonstrated that use of Z. multiflora Boiss. essential oil in the liquid phase was more effective than in vapor phase. The antibacterial zein-based films showed that active zein film with 5 and 10% Z. multiflora Boiss. essential oil had reductions of 1.68 log and 2.99 log, respectively, against Listeria monocytogenes and 1.39 and 3.07 log against Escherichia coli. Nano active zein film containing 10% Z. multiflora Boiss. essential oil and 2% sodium bentonite clay showed better antibacterial properties against L. monocytogenes (3.23 log) and E. coli (3.17 log).

  18. Modified clay sorbents

    DOEpatents

    Fogler, H. Scott; Srinivasan, Keeran R.

    1990-01-01

    A novel modified clay sorbent and method of treating industrial effluents to remove trace pollutants, such as dioxins, biphenyls, and polyaromatics such as benzo(a)pyrene and pentachlorophenol. The novel clay sorbent has a composite structure in which the interlayer space of an expandable clay, such as smectite, is filled with polyvalent or multivalent inorganic cations which forces weaker surfactant cations to locate on the surface of the clay in such an orientation that the resulting composite is hydrophilic in nature. A specific example is cetylpyridinium-hydroxy aluminum-montmorillonite. In certain embodiments, a non-expanding clay, such as kaolinite, is used and surfactant cations are necessarily located on an external surface of the clay. A specific example is cetylpyridinium-kaolinite.

  19. Permeability of Clay Concretes

    NASA Astrophysics Data System (ADS)

    Solomon, F.; Ekolu, S. O.

    2015-11-01

    This paper presents an investigation on the effect of clay addition on water permeability and air permeability of concretes. Clay concrete mixes consisted of 0 to 40% clay content incorporated as cement replacement. Flow methods using triaxial cells and air permeameters were used for measuring the injected water and air flows under pressure. It was found that the higher the clay content in the mixture, the greater the permeability. At higher water-cement ratios (w/c), the paste matrix is less dense and easily allows water to ingress into concrete. But at high clay contents of 30 to 40% clay, the variation in permeability was significantly diminished among different concrete mixtures. It was confirmed that air permeability results were higher than the corresponding water permeability values when all permeability coefficients were converted to intrinsic permeability values.

  20. Recent advances in clay mineral-containing nanocomposite hydrogels.

    PubMed

    Zhao, Li Zhi; Zhou, Chun Hui; Wang, Jing; Tong, Dong Shen; Yu, Wei Hua; Wang, Hao

    2015-12-28

    Clay mineral-containing nanocomposite hydrogels have been proven to have exceptional composition, properties, and applications, and consequently have attracted a significant amount of research effort over the past few years. The objective of this paper is to summarize and evaluate scientific advances in clay mineral-containing nanocomposite hydrogels in terms of their specific preparation, formation mechanisms, properties, and applications, and to identify the prevailing challenges and future directions in the field. The state-of-the-art of existing technologies and insights into the exfoliation of layered clay minerals, in particular montmorillonite and LAPONITE®, are discussed first. The formation and structural characteristics of polymer/clay nanocomposite hydrogels made from in situ free radical polymerization, supramolecular assembly, and freezing-thawing cycles are then examined. Studies indicate that additional hydrogen bonding, electrostatic interactions, coordination bonds, hydrophobic interaction, and even covalent bonds could occur between the clay mineral nanoplatelets and polymer chains, thereby leading to the formation of unique three-dimensional networks. Accordingly, the hydrogels exhibit exceptional optical and mechanical properties, swelling-deswelling behavior, and stimuli-responsiveness, reflecting the remarkable effects of clay minerals. With the pivotal roles of clay minerals in clay mineral-containing nanocomposite hydrogels, the nanocomposite hydrogels possess great potential as superabsorbents, drug vehicles, tissue scaffolds, wound dressing, and biosensors. Future studies should lay emphasis on the formation mechanisms with in-depth insights into interfacial interactions, the tactical functionalization of clay minerals and polymers for desired properties, and expanding of their applications.

  1. Provenance of the terrestrial planets.

    PubMed

    Wetherill, G W

    1994-01-01

    Earlier work on the simultaneous accumulation of the asteroid belt and the terrestrial planets is extended to investigate the relative contribution to the final planets made by material from different heliocentric distances. As before, stochastic variations intrinsic to the accumulation processes lead to a variety of final planetary configurations, but include systems having a number of features similar to our solar system. Fifty-nine new simulations are presented, from which thirteen are selected as more similar to our solar system than the others. It is found that the concept of "local feeding zones" for each final terrestrial planet has no validity for this model. Instead, the final terrestrial planets receive major contributions from bodies ranging from 0.5 to at least 2.5 AU, and often to greater distances. Nevertheless, there is a correlation between the final heliocentric distance of a planet and its average provenance. Together with the effect of stochastic fluctuations, this permits variation in the composition of the terrestrial planets, such as the difference in the decompressed density of Earth and Mars. Biologically important light elements, derived from the asteroidal region, are likely to have been significant constituents of the Earth during its formation.

  2. Super-active clay catalyst and use thereof

    SciTech Connect

    Goldstein, T.P.

    1980-03-18

    A super-active clay catalyst material prepared by a special method for treating clay materials is used in catalytic conversion of organic materials such as hydrocarbon compounds, heavy crude petroleum stock, and kerogen. The special method comprises contacting a clay material, existing in the raw state as found in nature or synthesized, with a solution containing cations selected from the group consisting of transition metal ions, aluminum ions, hydrogen ions, ions of metals from group IIB of the periodic table of elements and a combination thereof with each other, the clay material having been maintained at a temperature not exceeding 100 C prior to and during the contacting with the solution. Thereafter, the exchanged clay material is heated to a temperature of at least 50 C but not exceeding 250 C in the presence of air and/or organic material which is to be catalytically converted. 22 claims.

  3. Occurrence and identification of microorganisms in compacted clay-based buffer material designed for use in a nuclear fuel waste disposal vault.

    PubMed

    Stroes-Gascoyne, S; Pedersen, K; Haveman, S A; Dekeyser, K; Arlinger, J; Daumas, S; Ekendahl, S; Hallbeck, L; Hamon, C J; Jahromi, N; Delaney, T L

    1997-12-01

    A full-scale nuclear fuel waste disposal container experiment was carried out 240 m below ground in an underground granitic rock research laboratory in Canada. An electric heater was surrounded by buffer material composed of sand and bentonite clay and provided heat equivalent to what is anticipated in a Canadian nuclear fuel waste repository. During the experiment, the heat caused a mass transport of water and moisture content gradients developed in the buffer ranging from 13% closest to the heater to 23% at the rock wall of the deposition hole. Upon decommissioning after 2.5 years, microorganisms could be cultured from all samples having a moisture content above 15% but not from samples with a moisture content below 15%. Heterotrophic aerobic and anaerobic bacteria were found in numbers ranging from 10(1) to 10(6) cells/g dry weight buffer. Approximately 10(2), or less, sulphate-reducing bacteria and methanogens per gram of dry weight buffer were also found. Identification of buffer population members was performed using Analytical Profile Index (API) strips for isolated bacteria and 16S rRNA gene sequencing for in situ samples. A total of 79 isolates from five buffer layers were identified with API strips as representing the beta, gamma and delta groups of Proteobacteria and Gram-positive bacteria. Sixty-seven 16S rRNA clones that were obtained from three buffer layers were classified into 21 clone groups representing alpha and gamma groups of Proteobacteria, Gram-positive bacteria, and a yeast. Approximately 20% of the population comprised Gram-positive bacteria. Members of the genera Amycolatopsis, Bacillus, and Nocardia predominated. Among Gram-negative bacteria, the genera Acinetobacter and Pseudomonas predominated. Analysis of lipid biomarker signatures and in situ leucine uptake demonstrated that the buffer population was viable. The results suggest that a nuclear fuel waste buffer will be populated by active microorganisms only if the moisture content is

  4. Clay complexes support HDS catalyst.

    SciTech Connect

    Marshall, C. L.; Carrado, K.; Chemical Engineering

    2000-01-01

    Hydroprocessing represents a crucial component of petroleum refining operations both in terms of environmental and economic considerations. Regulations concerning maximum amount of sulfur content of gasoline and emissions of sulfur-oxide compounds upon combustion are becoming more and more stringent. One 1994-2000 focus of Argonne National Laboratory (ANL) has been the development of catalysts for hydrodesulfurization (HDS). Typical HDS catalysts are comprised of Co-Mo sulfides or Ni-Mo sulfides on an alumina support. Modification of the pore structure of the support has generated great attention among researchers. Most desulfurization test reactions have used dibenzothiophene (DBT) as the model compound to test various configurations of support material with Co-Mo-S and Ni-Mo-S catalysts. In this testing, the desired product would be biphenyl and hydrogen sulfide (H{sub 2}S). A competing reaction creates cyclohexylbenzene by saturating one aromatic ring prior to desulfurization. Ring saturation requires more costly hydrogen and is not desirable. Fortunately, a more effective catalyst for adding hydrogen at the sulfur site with hydrogenating the aromatic rings has been found. However, this has only been tested on DBT. HDS uses various types of catalysts to add hydrogen to reduce unwanted sulfur compounds. Typically this requires expensive, high-pressure, high-temperature equipment to produce the environmentally friendly low-sulfur fuels. ANL scientists identified several new desulfurization catalysts with improved HDS activity and selectivity. From these new catalysts, it may be possible to achieve HDS processing at lower temperature and pressure. The catalysts used for HDS at ANL are various clay complexes. Natural clays have a history of use in the hydroprocessing industry since they are abundant and inexpensive. ANL's approach is to create synthetic organo-clay complexes (SOCC). An advantage of SOCCs is that the pore size and distribution can be controlled by

  5. Clay Mineral: Radiological Characterization

    NASA Astrophysics Data System (ADS)

    Cotomácio, J. G.; Silva, P. S. C.; Mazzilli, B. P.

    2008-08-01

    Since the early days, clays have been used for therapeutic purposes. Nowadays, most minerals applied as anti-inflammatory, pharmaceutics and cosmetic are the clay minerals that are used as the active ingredient or, as the excipient, in formulations. Although their large use, few information is available in literature on the content of the radionuclide concentrations of uranium and thorium natural series and 40K in these clay minerals. The objective of this work is to determine the concentrations of 238U, 232Th, 226Ra, 228Ra, 210Pb and 40K in commercial samples of clay minerals used for pharmaceutical or cosmetic purposes. Two kinds of clays samples were obtained in pharmacies, named green clay and white clay. Measurement for the determination of 238U and 232Th activity concentration was made by alpha spectrometry and gamma spectrometry was used for 226Ra, 228Ra, 210Pb and 40K determination. Some physical-chemical parameters were also determined as organic carbon and pH. The average activity concentration obtained was 906±340 Bq kg-1 for 40K, 40±9 Bq kg-1 for 226Ra, 75±9 Bq kg-1 for 228Ra, 197±38 Bq kg-1 for 210Pb, 51±26 Bq kg-1 for 238U and 55±24 Bq kg-1 for 232Th, considering both kinds of clay.

  6. The Science of Clay

    ERIC Educational Resources Information Center

    Warwick, Sharon

    2005-01-01

    Students' natural curiosity provides a rich opportunity for teachers to make meaningful scientific connections between art and ceramics that will enhance the understanding of both natural forces and scientific aspects at work in the creation of clay artworks. This article discusses the scientific areas of study related to clay, which include…

  7. Finicky clay divers

    NASA Astrophysics Data System (ADS)

    Cordry, Sean M.

    1998-02-01

    Clay spheres dropped into a dilute vinegar/baking-soda solution accumulate CO2 bubbles on their surfaces. Spheres below a certain size will then float, otherwise they remain sunken. Students must determine the maximum size that will float by considering the net density of the clay/bubble system.

  8. Common clay and shale

    USGS Publications Warehouse

    Virta, R.L.

    2003-01-01

    Part of the 2002 industrial minerals review. The production, consumption, and price of shale and common clay in the U.S. during 2002 are discussed. The impact of EPA regulations on brick and structural clay product manufacturers is also outlined.

  9. Columns in Clay

    ERIC Educational Resources Information Center

    Leenhouts, Robin

    2010-01-01

    This article describes a clay project for students studying Greece and Rome. It provides a wonderful way to learn slab construction techniques by making small clay column capitols. With this lesson, students learn architectural vocabulary and history, understand the importance of classical architectural forms and their influence on today's…

  10. The Science of Clay

    ERIC Educational Resources Information Center

    Warwick, Sharon

    2005-01-01

    Students' natural curiosity provides a rich opportunity for teachers to make meaningful scientific connections between art and ceramics that will enhance the understanding of both natural forces and scientific aspects at work in the creation of clay artworks. This article discusses the scientific areas of study related to clay, which include…

  11. Clay Portrait Boxes

    ERIC Educational Resources Information Center

    Wilbert, Nancy Corrigan

    2009-01-01

    In an attempt to incorporate sculptural elements into her ceramics program, the author decided to try direct plaster casting of the face to make a plaster mold for clay. In this article, the author shares an innovative ceramics lesson that teaches students in making plaster casts and casting the face in clay. This project gives students the…

  12. Columns in Clay

    ERIC Educational Resources Information Center

    Leenhouts, Robin

    2010-01-01

    This article describes a clay project for students studying Greece and Rome. It provides a wonderful way to learn slab construction techniques by making small clay column capitols. With this lesson, students learn architectural vocabulary and history, understand the importance of classical architectural forms and their influence on today's…

  13. Clay Portrait Boxes

    ERIC Educational Resources Information Center

    Wilbert, Nancy Corrigan

    2009-01-01

    In an attempt to incorporate sculptural elements into her ceramics program, the author decided to try direct plaster casting of the face to make a plaster mold for clay. In this article, the author shares an innovative ceramics lesson that teaches students in making plaster casts and casting the face in clay. This project gives students the…

  14. Fine particle clay catalysts for coal liquefaction

    SciTech Connect

    Olson, E.S.

    1991-01-01

    The efficient production of environmentally acceptable distillate fuels requires catalysts for hydrogenation and cleavage of the coal macromolecules and removal of oxygen, nitrogen, and sulfur heteroatoms. The goal of the proposed research is to develop new catalysts for the direct liquefaction of coal. This type of catalyst consists of fine clay particles that have been treated with reagents which form pillaring structures between the aluminosilicate layers of the clay. The pillars not only hold the layers apart but also constitute the active catalytic sites for hydrogenation of the coal and solvent used in the liquefaction. The pillaring catalytic sites are composed of pyrrhotite, which has been previously demonstrated to be active for coal liquefaction. The pyrrhotite sites are generated in situ by sulfiding the corresponding oxyiron species. The size of the catalyst will be less than 40 nm in order to promote intimate contact with the coal material. Since the clays and reagents for pillaring and activating the clays are inexpensive, the catalysts can be discarded after use, rather than regenerated by a costly process. The proposed work will evaluate methods for preparing the fine particle iron-pillared clay dispersions and for activating the particles to generate the catalysts. Characterization studies of the pillared clays and activated catalysts will performed. The effectiveness of the pillared clay dispersion for hydrogenation and coal liquefaction will be determined in several types of testing. 5 refs., 1 tab.

  15. Fine particle clay catalysts for coal liquefaction

    SciTech Connect

    Olson, E.S.

    1991-01-01

    The efficient production of environmentally acceptable distillate fuels requires catalysts for hydrogenation and cleavage of the coal macromolecules and removal of oxygen, nitrogen, and sulfur heteroatoms. The goal of the proposed research is to develop new catalysts for the direct liquefaction of coal. This type of catalyst consists of fine clay particles that have been treated with reagents which form pillaring structures between the aluminosilicate layers of the clay. The pillars not only hold the layers apart but also constitute the active catalytic sites for hydrogenation of the coal and the solvent used in the liquefaction. The pillaring catalytic sites are composed of pyrrhotite, which has been previously demonstrated to be active for coal liquefaction. The pyrrhotite sites are generated in situ by sulfiding the corresponding oxyiron species. The size of the catalyst will be less than 40 nm in order to promote intimate contact with the coal material. Since the clays and reagents for pillaring and activating the clays are inexpensive, the catalysts can be discarded after use, rather than regenerated by a costly process. The proposed work will evaluate methods for preparing the fine particle iron-pillared clay dispersions and for activating the particles to generate the catalysts. Characterization studies of the pillared clays and activated catalysts will be performed. The effectiveness of the pillared clay dispersion for hydrogenation and coal liquefaction will be determined in several types of testing.

  16. Phosphates in some missouri refractory clays

    USGS Publications Warehouse

    Hall, R.B.; Foord, E.E.; Keller, D.J.; Keller, W.D.

    1997-01-01

    This paper describes in detail phosphate minerals occurring in refractory clays of Missouri and their effect on the refractory degree of the clays. The minerals identified include carbonate-fluorapatite (francolite), crandallite, goyazite, wavellite, variscite and strengite. It is emphasized that these phosphates occur only in local isolated concentrations, and not generally in Missouri refractory clays. The Missouri fireclay region comprises 2 districts, northern and southern, separated by the Missouri River In this region, clay constitutes a major part of the Lower Pennsylvanian Cheltenham Formation. The original Cheltenham mud was an argillic residue derived from leaching and dissolution of pre-Pennsylvanian carbonates. The mud accumulated on a karstic erosion surface truncating the pre-Cheltenham rocks. Fireclays of the northern district consist mainly of poorly ordered kaolinite, with variable but minor amounts of illite, chlorite and fine-grained detrital quartz. Clays of the southern district were subjected to extreme leaching that produced well-ordered kaolinite flint clays. Local desilication formed pockets of diaspora, or more commonly, kaolinite, with oolite-like nubs or burls of diaspore ("burley" clay). The phosphate-bearing materials have been studied by X-ray diffraction (XRD), scanning electron microscopy-energy dispersive spectral analysis (SEM-EDS) and chemical analysis. Calcian goyazite was identified in a sample of diaspore, and francolite in a sample of flint clay. A veinlet of wavellite occurs in flint clay at one locality, and a veinlet of variscite-strengite at another locality. The Missouri flint-clay-hosted francolite could not have formed in the same manner as marine francolite The evidence suggests that the Cheltenham francolite precipitated from ion complexes in pore water nearly simultaneously with crystallization of kaolinite flint clay from an alumina-silica gel. Calcian goyazite is an early diagenetic addition to its diaspore host

  17. Clay mineral type effect on bacterial enteropathogen survival in soil.

    PubMed

    Brennan, Fiona P; Moynihan, Emma; Griffiths, Bryan S; Hillier, Stephen; Owen, Jason; Pendlowski, Helen; Avery, Lisa M

    2014-01-15

    Enteropathogens released into the environment can represent a serious risk to public health. Soil clay content has long been known to have an important effect on enteropathogen survival in soil, generally enhancing survival. However, clay mineral composition in soils varies, and different clay minerals have specific physiochemical properties that would be expected to impact differentially on survival. This work investigated the effect of clay materials, with a predominance of a particular mineral type (montmorillonite, kaolinite, or illite), on the survival in soil microcosms over 96 days of Listeria monocytogenes, Salmonella Dublin, and Escherichia coli O157. Clay mineral addition was found to alter a number of physicochemical parameters in soil, including cation exchange capacity and surface area, and this was specific to the mineral type. Clay mineral addition enhanced enteropathogen survival in soil. The type of clay mineral was found to differentially affect enteropathogen survival and the effect was enteropathogen-specific. © 2013.

  18. Adsorption of dyes using different types of clay: a review

    NASA Astrophysics Data System (ADS)

    Adeyemo, Aderonke Ajibola; Adeoye, Idowu Olatunbosun; Bello, Olugbenga Solomon

    2015-09-01

    Increasing amount of dyes in the ecosystem particularly in wastewater has propelled the search for more efficient low-cost adsorbents. The effective use of the sorption properties (high surface area and surface chemistry, lack of toxicity and potential for ion exchange) of different clays as adsorbents for the removal of different type of dyes (basic, acidic, reactive) from water and wastewater as potential alternatives to activated carbons has recently received widespread attention because of the environmental-friendly nature of clay materials. Insights into the efficiencies of raw and modified/activated clay adsorbents and ways of improving their efficiencies to obtain better results are discussed. Acid-modified clay resulted in higher rate of dye adsorption and an increased surface area and porosity (49.05 mm2 and 53.4 %). Base-modified clay has lower adsorption capacities, while ZnCl2-modified clay had the least rate of adsorption with a surface area of 44.3 mm2 and porosity of 43.4 %. This review also explores the grey areas of the adsorption properties of the raw clays and the improved performance of activated/modified clay materials with particular reference to the effects of pH, temperature, initial dye concentration and adsorbent dosage on the adsorption capacities of the clays. Various challenges encountered in using clay materials are highlighted and a number of future prospects for the adsorbents are proposed.

  19. Adsorption of dyes using different types of clay: a review

    NASA Astrophysics Data System (ADS)

    Adeyemo, Aderonke Ajibola; Adeoye, Idowu Olatunbosun; Bello, Olugbenga Solomon

    2017-05-01

    Increasing amount of dyes in the ecosystem particularly in wastewater has propelled the search for more efficient low-cost adsorbents. The effective use of the sorption properties (high surface area and surface chemistry, lack of toxicity and potential for ion exchange) of different clays as adsorbents for the removal of different type of dyes (basic, acidic, reactive) from water and wastewater as potential alternatives to activated carbons has recently received widespread attention because of the environmental-friendly nature of clay materials. Insights into the efficiencies of raw and modified/activated clay adsorbents and ways of improving their efficiencies to obtain better results are discussed. Acid-modified clay resulted in higher rate of dye adsorption and an increased surface area and porosity (49.05 mm2 and 53.4 %). Base-modified clay has lower adsorption capacities, while ZnCl2-modified clay had the least rate of adsorption with a surface area of 44.3 mm2 and porosity of 43.4 %. This review also explores the grey areas of the adsorption properties of the raw clays and the improved performance of activated/modified clay materials with particular reference to the effects of pH, temperature, initial dye concentration and adsorbent dosage on the adsorption capacities of the clays. Various challenges encountered in using clay materials are highlighted and a number of future prospects for the adsorbents are proposed.

  20. A new locality of palygorskite-rich clay from the southeastern Yucatán: a potential material source for environmental applications

    NASA Astrophysics Data System (ADS)

    Krekeler, Mark P. S.; Kearns, Lance E.

    2009-08-01

    A palygorskite unit was discovered in a road cut of undifferentiated Tertiary limestone between the villages of El Pariso and San Roman (18°49.309N, 88°37.861W) in the southeastern Yucatán Peninsula, Mexico. This is the southern most locality of a clay-rich sedimentary unit reported in the literature for the Tertiary carbonates of the Yucatán Peninsula. This occurrence indicates a much wider range of palygorskite-rich clay deposition than previously recognized. The lithology is 99% clay and 1% sand to silt size diagenetic quartz grains. The clay consists of approximately 85% palygorskite, 15% montmorillonite and trace amounts of titanium oxides. EDS analyses on palygorskite are largely consistent with sedimentary palygorskites from other coastal marine settings, however palygorskite has a low total Fe content (average = 0.40 wt% expressed as Fe2O3) compared to many other sedimentary palygorskites. Montmorillonite chemical compositions are typical and compared to the palygorskite have substantially higher Fe2O3 concentrations (average = 3.90 wt%). The low percentage of coarse grains in the lithology combined with a high proportion of palygorskite and lack of detrimental trace minerals suggest the deposit is of industrial grade; however, it has limited reserves (6,000 m3). The unit could be potentially used in a wide array of environmental applications which are needed in the region including liners for landfills and constructed wetlands. The unit is in a geographic location which would serve the expanding economy of the region. This resource has the potential to have great impact on the quality of the local environment and the economy of a region under great environmental threat.

  1. High-resolution hyperspectral imaging of diagenesis and clays in fossil coral reef material: a nondestructive tool for improving environmental and climate reconstructions

    NASA Astrophysics Data System (ADS)

    Murphy, R. J.; Webster, J. M.; Nothdurft, L.; Dechnik, B.; McGregor, H. V.; Patterson, M. A.; Sanborn, K. L.; Webb, G. E.; Kearney, L. I.; Rintoul, L.; Erler, D. V.

    2017-08-01

    Hyperspectral imagery (1000-2500 nm) was used to quantitatively map carbonate and clay minerals in fossil reef cores that are relevant to accurately reconstructing past environmental and climatic conditions. Techniques were developed using hyperspectral imagery of fossil reef corals and cores acquired from three different geological settings, and were validated against independent measures of calcite to aragonite ratios. Aragonite, calcite, and dolomite were distinguished using a combination of the wavelength position and asymmetry of the primary carbonate absorption between 2300 and 2350 nm. Areas of core containing small amounts of calcite (>2-5%) were distinguished from aragonite in imagery of two cores, enabling quantitative maps of these minerals to be constructed. Dolomite was found to be the dominant mineral in another core. Trace amounts of the aluminium-rich clay mineral kaolinite were detected, quantified, and mapped in one core using its diagnostic absorption feature near 2200 nm. The amounts of clay detected from hyperspectral imagery were below the limits of detection by standard X-ray diffraction techniques but its presence was confirmed by Fourier Transform Infrared Spectroscopy. Hyperspectral imagery acquired at high spatial resolution simplifies vetting procedures for secondary carbonate minerals in coral reef cores, significantly reduces sampling time and costs, and is a powerful nondestructive tool to identify well-preserved coral aragonite in cores for uses in paleoclimate, paleoenvironment and paleoecosystem reconstruction.

  2. Clays causing adhesion with tool surfaces during mechanical tunnel driving

    NASA Astrophysics Data System (ADS)

    Spagnoli, G.; Fernández-Steeger, T.; Stanjek, H.; Feinendegen, M.; Post, C.; Azzam, R.

    2009-04-01

    During mechanical excavation with a tunnel boring machine (TBM) it is possible that clays stick to the cutting wheel and to other metal parts. The resulting delays in the progress of construction work, cause great economic damage and often disputes between the public awarding authorities and executing companies. One of the most important factors to reduce successfully the clay adhesion is the use of special polymers and foams. But why does the clay stick to the metal parts? A first step is to recognize which kind of clay mineralogy shows serious adhesion problems. The mechanical properties of clay and clay suspensions are primarily determined by surface chemistry and charge distribution at the interfaces, which in turn affect the arrangement of the clay structure. As we know, clay is a multi-phase material and its behaviour depends on numerous parameters such as: clay mineralogy, clay fraction, silt fraction, sand fraction, water content, water saturation, Atterberg limits, sticky limit, activity, cation exchange capacity, degree of consolidation and stress state. It is therefore likely that adhesion of clay on steel is also affected by these clay parameters. Samples of clay formations, which caused problems during tunnel driving, will be analyzed in laboratory. Mineralogical analyses (diffractometry, etc.) will be carried out to observe which minerals are responsible for adherence problems. To manipulate the physical properties, batch tests will be carried out in order to eliminate or reduce the adhesion on tool surfaces through variation of the zeta potential. Second step is the performance of vane shear tests on clay samples. Different pore fluid (distilled water, pure NaCl solution, ethanol and methanol) will be used to study the variation of the mechanical behaviour of clay depending on the dielectric constant of the fluids. This project is funded by the German Federal Ministry of Education and Research (BMBF) and the DFG (German Research Foundation) in the

  3. Polymer-clay interactions and their effect on the mechanical properties of their corresponding hybrids

    NASA Astrophysics Data System (ADS)

    Zanoaga, M.; Tanasa, I.; Tanasa, F.

    2015-12-01

    Understanding the polymer-clay interaction is one of the most important issues in the study of composites, since it is giving an insight into the formulation-properties relationship of the analyzed material. By evaluating the composites behaviour under operating conditions in real time, it is possible not only to reach shorter routes from concept to design, but to designate the most appropriate field of applications, as well. It is proven that micro- and nanometer scale fillers (various types and shapes of particles, fibers, tubes, sheets etc.) determine major improvements in the properties of the considered polymers. Factors as the matrix:filler ratio, the nature and compatibility of matrix and filler, the filler aspect ratio, and its wettability by the matrix as an indication on the hydrophil/hydrophob character, may significantly alter the properties improvement. In the case of layered silicates, their corresponding polymeric hybrid materials have shown improved characteristics, mainly in terms of mechanical behaviour, gas permeability and flammability. In this paper we present a comparative study of two series of polymer-clay hybrids based on polypropylene (PP) and a ternary aliphatic copolyamide (coPA), assessing the mechanical properties evolution in correlation with the nature and characteristics of the clays employed.

  4. Natural Radioactivity of Boron Added Clay Samples

    SciTech Connect

    Akkurt, I.; Guenoglu, K.; Canakcii, H.; Mavi, B.

    2011-12-26

    Clay, consisting fine-grained minerals, is an interesting materials and can be used in a variety of different fields especially in dermatology application. Using clay such a field it is important to measure its natural radioactivity. Thus the purpose of this study is to measure {sup 226}Ra, {sup 232}Th and {sup 40}K concentration in clay samples enriched with boron. Three different types of clay samples were prepared where boron is used in different rate. The measurements have been determined using a gamma-ray spectrometry consists of a 3''x3'' NaI(Tl) detector. From the measured activity the radium equivalent activities (Ra{sub eq}), external hazard index (H{sub ex}), absorbed dose rate in air (D) and annual effective dose (AED) have also been obtained.

  5. Natural Radioactivity of Boron Added Clay Samples

    NASA Astrophysics Data System (ADS)

    Akkurt, I.; ćanakciı, H.; Mavi, B.; Günoǧlu, K.

    2011-12-01

    Clay, consisting fine-grained minerals, is an interesting materials and can be used in a variety of diferent fields especially in dermatology application. Using clay such a field it is important to measure its natural radioacitivty. Thus the purpose of this study is to measure 226Ra, 232Th and 40K concentration in clay samples enriched with boron. Three different types of clay samples were prepared where boron is used in different rate. The measurements have been determined using a gamma-ray spectrometry consists of a 3″×3″ NaI(Tl) detector. From the measured activity the radium equivalent activities (Raeq), external hazard index (Hex), absorbed dose rate in air (D) and annual effective dose (AED) have also been obtained.

  6. Thermal analysis of selected illite and smectite clay minerals. Part I. Illite clay specimens

    NASA Astrophysics Data System (ADS)

    Earnest, C. M.

    The characterization of illite clay minerals by the use of the technique of differential thermal analysis (DTA), thermogravimetry (TG) and derivative thermogravimetry (DTG) is presented. This presentation is offered not only as a review of the thermal characteristics of this important group of clay materials but suggestions relative to the application of the thermal analysis techniques to contaminated illitic specimens; i.e., mineral mixtures, are included. Two commonly referenced illitic clay specimens, which have been widely distributed, were studied here. These were the American Petroleum Institute Reference Clay Specimen from Fithian, Illinois (API #35) and the Clay Mineral Society's Source Clay Specimen from Silver Hill, Montana (CMS-IMt). These clay specimens were studied using a modern computerized differential thermal analyzer which also contained a DSC mode of operation for peak energy assignment. Representative DTA thermal curves using both DTA and computerized DSC modes are given for both clay specimens. The effect of the variation of heating rate and sample size on the observed peak temperatures and resolution is demonstrated for both illite specimens.

  7. Clays as prebiotic photocatalysts

    NASA Technical Reports Server (NTRS)

    Coyne, L. M.; Lawless, J.; Lahav, N.; Sutton, S.; Sweeney, M.

    1981-01-01

    Clay minerals catalyze peptide bond formation in fluctuating environments. A number of plausible mechanisms have been proposed and tested. The possibility that clays may actually be energizing the reaction by means of electronic excitation, creating mobile or trapped holes and electrons in the lattice, is explored. It has been discovered that clays emit light upon dehydration. The correlation between dehydration-induced, or thermoluminescent, processes and the yield of glycine oligomers after treatments known to affect the luminescent yields is being tested, in an effort to understand the catalytic mechanism

  8. Modeling Radionuclide Transport in Clays

    SciTech Connect

    Zheng, Liange; Li, Lianchong; Rutqvist, Jonny; Liu, Hui -Hai; Birkholzer, Jens

    2012-05-01

    Clay/shale has been considered as potential host rock for geological disposal of high-level nuclear waste throughout the world, because of its low permeability, low diffusion coefficient, high retention capacity for radionuclides, and capability to self-seal fractures induced by tunnel excavation. For example, Callovo-Oxfordian argillites at the Bure site, France (Fouche et al., 2004), Toarcian argillites at the Tournemire site, France (Patriarche et al., 2004), Opalinus Clay at the Mont Terri site, Switzerland (Meier et al., 2000), and Boom clay at the Mol site, Belgium (Barnichon and Volckaert, 2003) have all been under intensive scientific investigation (at both field and laboratory scales) for understanding a variety of rock properties and their relationships to flow and transport processes associated with geological disposal of nuclear waste. Clay/shale formations may be generally classified as indurated or plastic clays (Tsang and Hudson, 2010). The latter (including Boom clay) is a softer material without high cohesion; its deformation is dominantly plastic. During the lifespan of a clay repository, the repository performance is affected by complex thermal, hydrogeological, mechanical, chemical (THMC) processes, such as heat release due to radionuclide decay, multiphase flow, formation of damage zones, radionuclide transport, waste dissolution, and chemical reactions. All these processes are related to each other. An in-depth understanding of these coupled processes is critical for the performance assessment (PA) of the repository. These coupled processes may affect radionuclide transport by changing transport paths (e.g., formation and evolution of excavation damaged zone (EDZ)) and altering flow, mineral, and mechanical properties that are related to radionuclide transport. While radionuclide transport in clay formation has been studied using laboratory tests (e,g, Appelo et al. 2010, Garcia-Gutierrez et al., 2008, Maes et al., 2008), short-term field

  9. Geotechnical characterization of mined clay from Appalachian Ohio: challenges and implications for the clay mining industry.

    PubMed

    Moran, Anthony R; Hettiarachchi, Hiroshan

    2011-07-01

    Clayey soil found in coal mines in Appalachian Ohio is often sold to landfills for constructing Recompacted Soil Liners (RSL) in landfills. Since clayey soils possess low hydraulic conductivity, the suitability of mined clay for RSL in Ohio is first assessed by determining its clay content. When soil samples are tested in a laboratory, the same engineering properties are typically expected for the soils originated from the same source, provided that the testing techniques applied are standard, but mined clay from Appalachian Ohio has shown drastic differences in particle size distribution depending on the sampling and/or laboratory processing methods. Sometimes more than a 10 percent decrease in the clay content is observed in the samples collected at the stockpiles, compared to those collected through reverse circulation drilling. This discrepancy poses a challenge to geotechnical engineers who work on the prequalification process of RSL material as it can result in misleading estimates of the hydraulic conductivity of the samples. This paper describes a laboratory investigation conducted on mined clay from Appalachian Ohio to determine how and why the standard sampling and/or processing methods can affect the grain-size distributions. The variation in the clay content was determined to be due to heavy concentrations of shale fragments in the clayey soils. It was also concluded that, in order to obtain reliable grain size distributions from the samples collected at a stockpile of mined clay, the material needs to be processed using a soil grinder. Otherwise, the samples should be collected through drilling.

  10. Hybrid inorganic-organic materials: Novel poly(propylene oxide)-based ceramers, abrasion-resistant sol-gel coatings for metals, and epoxy-clay nanocomposites, with an additional chapter on: Metallocene-catalyzed linear polyethylene

    NASA Astrophysics Data System (ADS)

    Jordens, Kurt

    1999-12-01

    The sol-gel process has been employed to generate hybrid inorganic-organic network materials. Unique ceramers were prepared based on an alkoxysilane functionalized soft organic oligomer, poly(propylene oxide (PPO), and tetramethoxysilane (TMOS). Despite the formation of covalent bonds between the inorganic and organic constituents, the resulting network materials were phase separated, composed of a silicate rich phase embedded in a matrix of the organic oligomer chains. The behavior of such materials was similar to elastomers containing a reinforcing filler. The study focused on the influence of initial oligomer molecular weight, functionality, and tetramethoxysilane, water, and acid catalyst content on the final structure, mechanical and thermal properties. The sol-gel approach has also been exploited to generate thin, transparent, abrasion resistant coatings for metal substrates. These systems were based on alkoxysilane functionalized diethylenetriamine (DETA) with TMOS, which generated hybrid networks with very high crosslink densities. These materials were applied with great success as abrasion resistant coatings to aluminum, copper, brass, and stainless steel. In another study, intercalated polymer-clay nanocomposites were prepared based on various epoxy networks montmorillonite clay. This work explored the influence of incorporated clay on the adhesive properties of the epoxies. The lap shear strength decreased with increasing day content This was due to a reduction in the toughness of the epoxy. Also, the delaminated (or exfoliated) nanocomposite structure could not be generated. Instead, all nanocomposite systems possessed an intercalated structure. The final project involved the characterization of a series of metallocene catalyzed linear polyethylenes, produced at Phillips Petroleum. Polyolefins synthesized with such new catalyst systems are becoming widely available. The influence of molecular weight and thermal treatment on the mechanical, rheological

  11. Characterization of clay from northern of Morocco for their industrial application

    NASA Astrophysics Data System (ADS)

    El Ouahabi, Meriam; Fagel, Nathalie

    2010-05-01

    Clays are a natural resource used for millennia. Currently applications such as industrial minerals are diversified. In this context, our goal is to estimate the potential of the many clay deposits in northern of Morocco. The choice of this region is justified by the particular abundance of clay deposits used to manufacture building materials (brick, ceramic and refractories) and pottery. This study focuses on the mineralogical, chemical and geotechnical characterization tests carried out on Tangier-Tetouan and Meknes clays from northern of Morocco. The suitability of raw clay material from those regions in order to produce ceramic and brick has not been tested yet. The results revealed that the studied samples are diversified, kaolinite and illite (Tetouan clay) and kaolinite and illite and smectite and vermiculite (Tangier and Meknes clay) based materials. There were no major differences in grain-size distribution, whereas Meknes clay was more plastic than Tetouan-Tangier clay. The cation exchange capacity show that Meknes and Tangier clay were more important than Tetouan clay. Specific surface area and thermal analaysis complete this caracterization. It was found that almost all technological properties of the Meknes clay deposit are led to the manufacture of ceramic floor tile, and Tetouan-Tangier clay provide opportunities to making brick and ceramic floor. The Tetouan-Tangier and Meknes clay are a potential ceramic raw material for growing Morrocan ceramic tile and brick industries.

  12. A Noisy 10GB Provenance Database

    SciTech Connect

    Cheah, You-Wei; Plale, Beth; Kendall-Morwick, Joey; Leake, David; Ramakrishnan, Lavanya

    2011-06-06

    Provenance of scientific data is a key piece of the metadata record for the data's ongoing discovery and reuse. Provenance collection systems capture provenance on the fly, however, the protocol between application and provenance tool may not be reliable. Consequently, the provenance record can be partial, partitioned, and simply inaccurate. We use a workflow emulator that models faults to construct a large 10GB database of provenance that we know is noisy (that is, has errors). We discuss the process of generating the provenance database, and show early results on the kinds of provenance analysis enabled by the large provenance.

  13. Clay Mineral: Radiological Characterization

    SciTech Connect

    Cotomacio, J. G.; Silva, P. S. C.; Mazzilli, B. P

    2008-08-07

    Since the early days, clays have been used for therapeutic purposes. Nowadays, most minerals applied as anti-inflammatory, pharmaceutics and cosmetic are the clay minerals that are used as the active ingredient or, as the excipient, in formulations. Although their large use, few information is available in literature on the content of the radionuclide concentrations of uranium and thorium natural series and {sup 40}K in these clay minerals.The objective of this work is to determine the concentrations of {sup 238}U, {sup 232}Th, {sup 226}Ra, {sup 228}Ra, {sup 210}Pb and {sup 40}K in commercial samples of clay minerals used for pharmaceutical or cosmetic purposes. Two kinds of clays samples were obtained in pharmacies, named green clay and white clay.Measurement for the determination of {sup 238}U and {sup 232}Th activity concentration was made by alpha spectrometry and gamma spectrometry was used for {sup 226}Ra, {sup 228}Ra, {sup 210}Pb and {sup 40}K determination. Some physical-chemical parameters were also determined as organic carbon and pH. The average activity concentration obtained was 906{+-}340 Bq kg{sup -1} for {sup 40}K, 40{+-}9 Bq kg{sup -1} for {sup 226}Ra, 75{+-}9 Bq kg{sup -1} for {sup 228}Ra, 197{+-}38 Bq kg{sup -1} for {sup 210}Pb, 51{+-}26 Bq kg{sup -1} for {sup 238}U and 55{+-}24 Bq kg{sup -1} for {sup 232}Th, considering both kinds of clay.

  14. Designing in Clay

    ERIC Educational Resources Information Center

    Nigrosh, Leon I.

    1977-01-01

    What can be done to transform a lump of wet clay into something more than a lump of glaze-fired clay? It is at this point when forming techniques have been mastered that good design becomes most important. Discusses six criteria involved in the search for good design so that students can discover what good design is and how important it is.…

  15. Common clay and shale

    USGS Publications Warehouse

    Virta, R.L.

    2006-01-01

    At present, 150 companies produce common clay and shale in 41 US states. According to the United States Geological Survey (USGS), domestic production in 2005 reached 24.8 Mt valued at $176 million. In decreasing order by tonnage, the leading producer states include North Carolina, Texas, Alabama, Georgia and Ohio. For the whole year, residential and commercial building construction remained the major market for common clay and shale products such as brick, drain tile, lightweight aggregate, quarry tile and structural tile.

  16. Clay-Bacteria Systems and Biofilm Production

    NASA Astrophysics Data System (ADS)

    Steiner, J.; Alimova, A.; Katz, A.; Steiner, N.; Rudolph, E.; Gottlieb, P.

    2007-12-01

    Soil clots and the aerosol transport of bacteria and spores are promoted by the formation of biofilms (bacteria cells in an extracellular polymeric matrix). Biofilms protect microorganisms by promoting adhesion to both organic and inorganic surfaces. Time series experiments on bacteria-clay suspensions demonstrate that biofilm growth is catalyzed by the presence of hectorite in minimal growth media for the studied species: Gram negatives (Pseudomonas syringae and Escherichia coli,) and Gram positives (Staphylococcus aureus and Bacillus subtilis). Soil organisms (P. syringae, B. subtilis) and organisms found in the human population (E. coli, S. aureus) are both used to demonstrate the general applicability of clay involvement. Fluorescent images of the biofilms are acquired by staining with propidium iodide, a component of the BacLightTM Live/Dead bacterial viability staining kit (Molecular Probes, Eugene, OR). The evolving polysaccharide-rich biofilm reacts with the clay interlayer site causing a complex substitution of the two-water hectorite interlayer with polysaccharide. The result is often a three-peak composite of the (001) x-ray diffraction maxima resulting from polysaccharide-expanded clays and an organic-driven contraction of a subset of the clays in the reaction medium. X-ray diffractograms reveal that the expanded set creates a broad maximum with clay subsets at 1.84 nm and 1.41 nm interlayer spacings as approximated by a least squares double Lorentzian fit, and a smaller shoulder at larger 2q, deriving from a contraction of the interlayer spacing. Washing with chlorox removes organic material from the contracted clay and creates a 1-water hectorite single peak in place of the double peak. The clay response can be used as an indirect indicator of biofilm in an environmental system.

  17. Geochemical Identification in Sediment Provenance during Glacial/Interglacial Period: the Southern Drake Passage

    NASA Astrophysics Data System (ADS)

    Park, Y. K.; Jung, J.; Lee, J. I.; Yoo, K. C.; Kim, J. W.

    2016-12-01

    Clay mineralogy and crystal size distribution in marine sediment is used for the indication of a sediment provenance and climatic changes. Objective of this study is to trace the sediment provenances in the Southern Drake Passage with clay mineralogy, elemental composition and crystal size distributions (CSDs) of clay mineral. In the present study, X-Ray Diffractometer (XRD) measurements showed that smectite, illite and chlorite are dominant phases. The semi-quantitative analysis showed that the relatively proportion of smectite is 50 - 60% in interglacial stage, 30 - 39% in glacial stage. Comparing with REE data, sediments supply was influenced by Weddell sea current and Antarctic Circumpolar Current (ACC). Moreover, elemental composition and microscopic analysis of smectites were carried by Transmission Electron Microscopy (TEM) and energy dispersive spectroscopy (EDS). The composition of smectite clay minerals were plotted on the tertiary diagram indicating that Smectite in Drake Passage was transported from three provenances: South Shetland island, east and west side of Antarctic peninsula during glacial - interglacial period. The CSDs of smectite also indicate the various source of smectite. The variation in the values of α (mean thickness) and β2 (shape or uniformity of the distribution) of smectite grain size will be discussed in terms of the sediment provenance.

  18. NMR imaging and cryoporometry of swelling clays

    NASA Astrophysics Data System (ADS)

    Dvinskikh, Sergey V.; Szutkowski, Kosma; Petrov, Oleg V.; Furó, István.

    2010-05-01

    Compacted bentonite clay is currently attracting attention as a promising "self-sealing" buffer material to build in-ground barriers for the encapsulation of radioactive waste. It is expected to fill up the space between waste canister and surrounding ground by swelling and thus delay flow and migration from the host rock to the canister. In environmental sciences, evaluation and understanding of the swelling properties of pre-compacted clay are of uttermost importance for designing such buffers. Major goal of present study was to provide, in a non-invasive manner, a quantitative measure of bentonite distribution in extended samples during different physical processes in an aqueous environment such as swelling, dissolution, and sedimentation on the time scale from minutes to years. The propagation of the swelling front during clay expansion depending on the geometry of the confining space was also studied. Magnetic resonance imaging and nuclear magnetic resonance spectroscopy were adapted and used as main experimental techniques. With this approach, spatially resolved movement of the clay/water interface as well as clay particle distributions in gel phase can be monitored [1]. Bulk samples with swelling in a vertical tube and in a horizontal channel were investigated and clay content distribution profiles in the concentration range over five orders of magnitude and with sub-millimetre spatial resolution were obtained. Expansion rates for bulk swelling and swelling in narrow slits were compared. For sodium-exchanged montmorillonite in contact with de-ionised water, we observed a remarkable acceleration of expansion as compared to that obtained in the bulk. To characterize the porosity of the clay a cryoporometric study [2] has been performed. Our results have important implications to waste repository designs and for the assessment of its long-term performance. Further research exploring clay-water interaction over a wide variety of clay composition and water ionic

  19. Understanding bias in provenance studies

    NASA Astrophysics Data System (ADS)

    Garzanti, Eduardo; Andò, Sergio; Malusà, Marco; Vezzoli, Giovanni

    2010-05-01

    Innumerable pieces of information are stored in the sedimentary archive. Each single sediment layer contains billions of detrital grains, and every grain preserves imprints of its geological story. If we learn to read, compare, and combine these messages properly, through a deeper understanding of physical and chemical processes that modify sediment composition during the sedimentary cycle, provenance analysis may eventually enable us to reconstruct more accurately the geological processes that shaped the Earth's crust in the past. Interpreting detrital modes is not straightforward because provenance signals issued from source rocks become progressively blurred by multiple noises in the sedimentary environment ("environmental bias"; Komar, 2007), and finally during post-depositional history ("diagenetic bias"; Morton and Hallsworth, 2007). During transport and deposition, detrital minerals are segregated in different size fractions and environments according to their size, density and shape (Rubey, 1933; Garzanti et al., 2008). Heavy-mineral concentration can increase by an order of magnitude due to selective-entrainment effects, with potentially overwhelming impact on chemical composition and provenance estimates based on detrital-geochronology data (Garzanti et al., 2009). Conversely, heavy-mineral concentration is typically reduced by an order of magnitude in Alpine and Himalayan foreland-basin deposits older than the Pleistocene (Garzanti and Andò, 2007). Extensive chemical dissolution can occur even prior to deposition during weathering in hot humid climates (Velbel, 2007). Primary provenance signals can be isolated and assessed by studying first modern sediments in hyperarid settings (i.e., free from diagenetic and weathering bias). Next, weathering, hydraulic-sorting, and diagenetic effects can be singled out by analysing sediments of similar provenance produced in contrasting climatic conditions, sediments transported in diverse modes and deposited in

  20. The influence of clay type on reduction of water repellency by applied clays: a review of some West Australian work

    NASA Astrophysics Data System (ADS)

    McKissock, I.; Walker, E. L.; Gilkes, R. J.; Carter, D. J.

    2000-05-01

    In Western Australia water repellency mostly occurs in soils with sandy texture; the severity of water repellency is influenced by very small changes in clay content. Additions of 1-2% clay can prevent water repellency and for some time clay amendments have been used by farmers to overcome water repellency. The aim of this study was to assess the effectiveness of clays in ameliorating water repellency. Clays were assessed for effectiveness in reducing water repellency by mixing with water repellent sands and measuring water drop penetration time (WDPT) on the resultant mixtures. WDPT was measured on the initial mixtures, a wetting and drying cycle was imposed and WDPT measured again. Two sets of clays were assessed: four simple clays containing kaolinite (2) or smectite (2) group minerals and a group of clayey subsoil materials which had been collected by farmers. For the simple clays, clay mineral type was the most significant factor in determining response. Kaolin was much more effective than smectite. Imposition of a wetting and drying cycle greatly reduced water repellency. The dominant exchangeable cation of the clays (sodium or calcium) had little effect on the ability of the clays to reduce water repellency. The factor that was most predictive of the effectiveness of clayey subsoils materials in reducing water repellency was texture: clay content ( r2=0.18) or clay+silt content ( r2=0.23). These properties were more predictive of water repellency values after the wetting and drying cycle treatment ( r2=0.36, r2=0.44). The proportion of the clay fraction that consisted of kaolinite was next most predictive in determining effectiveness which is again indicative of kaolin group minerals being more effective than smectite group minerals. The exchangeable sodium percentage and clay dispersibility had no systematic effect on the ability of these clays to reduce water repellency. These results provide a basis for developing a practical field procedure to enable

  1. Infrared analysis of clay bricks incorporated with spent shea waste from the shea butter industry.

    PubMed

    Adazabra, A N; Viruthagiri, G; Shanmugam, N

    2017-04-15

    The peculiar challenge of effective disposing abundant spent shea waste and the excellent compositional variation tolerance of clay material offered an impetus to examine the incorporation of spent shea waste into clay material as an eco-friendly disposal route in making clay bricks. For this purpose, the chemical constituent, mineralogical compositions and thermal behavior of both clay material and spent shea waste were initially characterized from which modelled brick specimens incorporating 5-20 wt% of the waste into the clay material were prepared. The clay material showed high proportions of SiO2 (52.97 wt%) and Al2O3 (27.10 wt%) indicating their rich kaolinitic content: whereas, the inert nature of spent shea waste was exhibited by their low oxide content. The striking similarities in infrared absorption bands of pristine clay material and clay materials incorporated with 15 wt% of spent shea waste showed that the waste incorporation had no impact on bond formation of the clay bricks. Potential performance benefits of developing bricks from clay material incorporated with spent shea waste included improved fluxing agents, economic sintering and making of sustainable bricks. Consequently, the analytical results authenticate the incorporation of spent shea waste into clay materials for various desired benefits aside being an environmental correct route of its disposal.

  2. Shock metamorphism of clay minerals on Mars by meteor impact

    NASA Astrophysics Data System (ADS)

    Michalski, Joseph R.; Glotch, Timothy D.; Friedlander, Lonia R.; Darby Dyar, M.; Bish, David L.; Sharp, Thomas G.; Carter, John

    2017-07-01

    A large fraction of clay minerals detected on Mars by infrared remote sensing represent materials exhumed from the subsurface by meteor impact, begging the question of whether the infrared features used to detect the clays are affected by shock associated with the impacts. We used X-ray diffraction and infrared and Mössbauer spectroscopy to evaluate the mineralogy of five clay minerals after experimentally shocking them to six shock pressures from 10 to 40 GPa. The shocked clays exhibit three main relevant shock effects: (1) an overall decrease in infrared spectral contrast in the impact-fragmented materials, (2) oxidation of Fe in ferrous clays, and (3) loss of some spectral structure in relatively well-ordered clays such as kaolinite. Other than the widespread oxidation of ferrous clays, shock metamorphism likely has little effect on the accurate interpretation of clay mineralogy on Mars from remote sensing data. However, we are able to identify rare cases of extreme shock in some Martian clay deposits.

  3. Films, Buckypapers and Fibers from Clay, Chitosan and Carbon Nanotubes

    PubMed Central

    Higgins, Thomas M.; Warren, Holly; Panhuis, Marc in het

    2011-01-01

    The mechanical and electrical characteristics of films, buckypapers and fiber materials from combinations of clay, carbon nanotubes (CNTs) and chitosan are described. The rheological time-dependent characteristics of clay are maintained in clay–carbon nanotube–chitosan composite dispersions. It is demonstrated that the addition of chitosan improves their mechanical characteristics, but decreases electrical conductivity by three-orders of magnitude compared to clay–CNT materials. We show that the electrical response upon exposure to humid atmosphere is influenced by clay-chitosan interactions, i.e., the resistance of clay–CNT materials decreases, whereas that of clay–CNT–chitosan increases. PMID:28348277

  4. The Open Provenance Model: an Overview

    SciTech Connect

    Moreau, Luc; Freire, Juliana; Futrelle, Joe; McGrath, Robert E.; Myers, Jim; Paulson, Patrick R.

    2008-11-19

    The Open Provenance Model (OPM) is a model for provenance that is designed to meet the following requirements: { To allow provenance information to be exchanged between systems, by means of a compatibility layer based on a shared provenance model. { To allow developers to build and share tools that operate on such provenance model. { To dene the model in a precise, technology-agnostic manner. { To support a digital representation of provenance for any \\thing", whether produced by computer systems or not. { To dene a core set of rules that identify the valid inferences that can be made on provenance graphs.

  5. Provenance management in Swift with implementation details.

    SciTech Connect

    Gadelha, L. M. R; Clifford, B.; Mattoso, M.; Wilde, M.; Foster, I.

    2011-04-01

    The Swift parallel scripting language allows for the specification, execution and analysis of large-scale computations in parallel and distributed environments. It incorporates a data model for recording and querying provenance information. In this article we describe these capabilities and evaluate interoperability with other systems through the use of the Open Provenance Model. We describe Swift's provenance data model and compare it to the Open Provenance Model. We also describe and evaluate activities performed within the Third Provenance Challenge, which consisted of implementing a specific scientific workflow, capturing and recording provenance information of its execution, performing provenance queries, and exchanging provenance information with other systems. Finally, we propose improvements to both the Open Provenance Model and Swift's provenance system.

  6. Quick clay and landslides of clayey soils.

    PubMed

    Khaldoun, Asmae; Moller, Peder; Fall, Abdoulaye; Wegdam, Gerard; De Leeuw, Bert; Méheust, Yves; Otto Fossum, Jon; Bonn, Daniel

    2009-10-30

    We study the rheology of quick clay, an unstable soil responsible for many landslides. We show that above a critical stress the material starts flowing abruptly with a very large viscosity decrease caused by the flow. This leads to avalanche behavior that accounts for the instability of quick clay soils. Reproducing landslides on a small scale in the laboratory shows that an additional factor that determines the violence of the slides is the inhomogeneity of the flow. We propose a simple yield stress model capable of reproducing the laboratory landslide data, allowing us to relate landslides to the measured rheology.

  7. File level provenance tracking in CMS

    SciTech Connect

    Jones, C.D.; Kowalkowski, J.; Paterno, M.; Sexton-Kennedy, L.; Tanenbaum, W.; Riley, D.S.; /Cornell U., LEPP

    2009-05-01

    The CMS off-line framework stores provenance information within CMS's standard ROOT event data files. The provenance information is used to track how each data product was constructed, including what other data products were read to do the construction. We will present how the framework gathers the provenance information, the efforts necessary to minimize the space used to store the provenance in the file and the tools that will be available to use the provenance.

  8. Moving Along: Sporting Clay.

    ERIC Educational Resources Information Center

    Hiller, Peter

    2002-01-01

    Presents a junior high school student art project where three-dimensional art sculptures of surfing, snow boarding, or dirt biking were created. Discusses how the students created their three-dimensional works of art using a clay-slab technique. (CMK)

  9. Moving Along: Sporting Clay.

    ERIC Educational Resources Information Center

    Hiller, Peter

    2002-01-01

    Presents a junior high school student art project where three-dimensional art sculptures of surfing, snow boarding, or dirt biking were created. Discusses how the students created their three-dimensional works of art using a clay-slab technique. (CMK)

  10. Common clay and shale

    USGS Publications Warehouse

    Virta, R.L.

    2001-01-01

    Part of the 2000 annual review of the industrial minerals sector. A general overview of the common clay and shale industry is provided. In 2000, U.S. production increased by 5 percent, while sales or use declined to 23.6 Mt. Despite the slowdown in the economy, no major changes are expected for the market.

  11. Rattles of Clay.

    ERIC Educational Resources Information Center

    Banning, Donna

    1983-01-01

    Using the rattles of Native American cultures as inspiration, students used pinching, coiling, and slab and molding techniques to form the bodies of rattles and clay pellets for sound. Surface decoration included glazed and unglazed areas as well as added handles, feathers, and leather. (IS)

  12. Rattles of Clay.

    ERIC Educational Resources Information Center

    Banning, Donna

    1983-01-01

    Using the rattles of Native American cultures as inspiration, students used pinching, coiling, and slab and molding techniques to form the bodies of rattles and clay pellets for sound. Surface decoration included glazed and unglazed areas as well as added handles, feathers, and leather. (IS)

  13. Clay Improvement with Burned Olive Waste Ash

    PubMed Central

    Mutman, Utkan

    2013-01-01

    Olive oil is concentrated in the Mediterranean basin countries. Since the olive oil industries are incriminated for a high quantity of pollution, it has become imperative to solve this problem by developing optimized systems for the treatment of olive oil wastes. This study proposes a solution to the problem. Burned olive waste ash is evaluated for using it as clay stabilizer. In a laboratory, bentonite clay is used to improve olive waste ash. Before the laboratory, the olive waste is burned at 550°C in the high temperature oven. The burned olive waste ash was added to bentonite clay with increasing 1% by weight from 1% to 10%. The study consisted of the following tests on samples treated with burned olive waste ash: Atterberg Limits, Standard Proctor Density, and Unconfined Compressive Strength Tests. The test results show promise for this material to be used as stabilizer and to solve many of the problems associated with its accumulation. PMID:23766671

  14. Organoclay Networking in Polypropylene-Clay Nanocomposites

    NASA Astrophysics Data System (ADS)

    Oberhauser, James; Treece, Mark

    2006-03-01

    We report on networking of organoclays and its influence on the rheology of polypropylene-clay nanocomposites. Samples are blended using either a twin screw extruder (TSE) or a single screw extruder with in situ addition of supercritical CO2 (SCCO2). Blends contain proportional amounts (3:1) of maleic anhydride functionalized PP and organically modified montmorillonite (Cloisite^ 15A, Southern Clay Products) at several clay loadings in a base PP resin (MFI 12 g/10 min at 230 C). Small-amplitude oscillatory shear (SAOS) and steady shear flow were utilized to probe clay morphology with varying annealing time. In SAOS experiments repeated over several hours, the terminal behavior of the TSE samples became increasingly solid-like; in steady shear, the magnitude of the viscosity overshoot increased with annealing time. The single-screw/SCCO2 materials at the same clay loadings differed little rheologically from the neat resin. Finally, network formation kinetics accelerated with increasing temperature, and sufficiently large deformations irreversibly weakened the network structure.

  15. Ontology-Driven Provenance Management in eScience: An Application in Parasite Research

    NASA Astrophysics Data System (ADS)

    Sahoo, Satya S.; Weatherly, D. Brent; Mutharaju, Raghava; Anantharam, Pramod; Sheth, Amit; Tarleton, Rick L.

    Provenance, from the French word "provenir", describes the lineage or history of a data entity. Provenance is critical information in scientific applications to verify experiment process, validate data quality and associate trust values with scientific results. Current industrial scale eScience projects require an end-to-end provenance management infrastructure. This infrastructure needs to be underpinned by formal semantics to enable analysis of large scale provenance information by software applications. Further, effective analysis of provenance information requires well-defined query mechanisms to support complex queries over large datasets. This paper introduces an ontology-driven provenance management infrastructure for biology experiment data, as part of the Semantic Problem Solving Environment (SPSE) for Trypanosoma cruzi (T.cruzi). This provenance infrastructure, called T.cruzi Provenance Management System (PMS), is underpinned by (a) a domain-specific provenance ontology called Parasite Experiment ontology, (b) specialized query operators for provenance analysis, and (c) a provenance query engine. The query engine uses a novel optimization technique based on materialized views called materialized provenance views (MPV) to scale with increasing data size and query complexity. This comprehensive ontology-driven provenance infrastructure not only allows effective tracking and management of ongoing experiments in the Tarleton Research Group at the Center for Tropical and Emerging Global Diseases (CTEGD), but also enables researchers to retrieve the complete provenance information of scientific results for publication in literature.

  16. Modeling the Provenance of Crater Ejecta

    NASA Astrophysics Data System (ADS)

    Huang, Ya-Huei; Minton, David A.

    2014-11-01

    The cratering history of the Moon provides a way to study the violent early history of our early solar system. Nevertheless, we are still limited in our ability to interpret the lunar cratering history because the complex process of generation and subsequent transportation and destruction of impact melt products is relatively poorly understood. Here we describe a preliminary model for the transport of datable impact melt products by craters over Gy timescales on the lunar surface. We use a numerical model based on the Maxwell Z-model to model the exhumation and transport of ejecta material from within the excavation flow of a transient crater. We describe our algorithm for rapidly estimating the provenance of ejecta material for use in a Monte Carlo cratering code capable of simulating lunar cratering over Gy timescales.

  17. Clay Animals and Their Habitats

    ERIC Educational Resources Information Center

    Adamson, Kay

    2010-01-01

    Creating clay animals and their habitats with second-grade students has long been one of the author's favorite classroom activities. Students love working with clay and they also enjoy drawing animal homes. In this article, the author describes how the students created a diorama instead of drawing their clay animal's habitat. This gave students…

  18. Clay Animals and Their Habitats

    ERIC Educational Resources Information Center

    Adamson, Kay

    2010-01-01

    Creating clay animals and their habitats with second-grade students has long been one of the author's favorite classroom activities. Students love working with clay and they also enjoy drawing animal homes. In this article, the author describes how the students created a diorama instead of drawing their clay animal's habitat. This gave students…

  19. Capability assessment for application of clay mixture as barrier material for irradiated zirconium alloy structure elements long-term processing for storage during decommissioning of uranium-graphite nuclear reactors

    NASA Astrophysics Data System (ADS)

    Kotlyarevskiy, S. G.; Pavliuk, A. O.; Zakharova, E. V.; Volkova, A. G.

    2016-06-01

    The radionuclide composition and the activity level of the irradiated zirconium alloy E110, the radionuclide immobilization strength and the retention properties of the mixed clay barrier material with respect to the radionuclides identified in the alloy were investigated to perform the safety assessment of handling structural units of zirconium alloy used for the technological channels in uranium-graphite reactors. The irradiated zirconium alloy waste contained the following activation products: 93mNb and the long-lived 94Nb, 93Zr radionuclides. Radionuclides of 60Co, 137Cs, 90Sr, and actinides were also present in the alloy. In the course of the runs no leaching of niobium and zirconium isotopes from the E110 alloy was detected. Leach rates were observed merely for 60Co and 137Cs present in the deposits formed on the internal surface of technological channels. The radionuclides present were effectively adsorbed by the barrier material. To ensure the localization of radionuclides in case of the radionuclide migration from the irradiated zirconium alloy into the barrier material, the sorption properties were determined of the barrier material used for creating the long-term storage point for the graphite stack from uranium-graphite reactors.

  20. Evidence for Smectite Clays from MSL SAM Analyses of Mudstone at Yellowknife Bay, Gale Crater, Mars

    NASA Astrophysics Data System (ADS)

    McAdam, A.; Franz, H.; Mahaffy, P. R.; Eigenbrode, J. L.; Stern, J. C.; Brunner, A.; Sutter, B.; Archer, P. D.; Ming, D. W.; Morris, R. V.; Atreya, S. K.; Team, M.

    2013-12-01

    Drilled samples of mudstone from the Sheepbed unit at Yellowknife Bay were analyzed by MSL instruments including the Sample Analysis at Mars (SAM) and Chemistry and Mineralogy (CheMin) instruments in MSL's Analytical Laboratory. CheMin analyses revealed the first in situ X-ray diffraction based evidence of clay minerals on Mars, which are likely trioctahedral smectites (e.g., saponite) and comprise ~20% of the mudstone sample (e.g., Bristow et al., this meeting). SAM analyses, which heated the mudstone samples to 1000oC and monitored volatiles evolved to perform in situ evolved gas analysis mass spectrometry (EGA-MS), resulted in a H2O trace exhibiting a wide evolution at temperatures <500oC, and an evolution peak at higher temperatures near ~750oC. The low temperature H2O evolution has many potential contributors, including adsorbed H2O, smectite interlayer H2O, and structural H2O/OH from bassanite and akaganeite (identified by CheMin) and H2O/OH from amorphous phases in the sample. The high temperature H2O is consistent with the evolution of H2O from the dehydroxylation of the smectite clay mineral. Comparison to EGA-MS data collected under SAM-like conditions on a variety of clay mineral reference materials indicate that a trioctahedral smectite, such as saponite, is most consistent with the high temperature H2O evolution observed. There may also be SAM EGA-MS evidence for a small high temperature H2O evolution from scoop samples from the Yellowknife Bay Rocknest sand shadow bedform. As in the mudstone samples, this evolution may indicate the detection of smectite clays, and the idea that minor clays may be present in Rocknest materials that could be expected to be at least partially derived from local sources is reasonable. But, because smectite clays were not definitively observed in CheMin analyses of Rocknest materials, they must be present at much lower abundances than the ~20% observed in the mudstone samples. This potential detection underscores the

  1. Evidence for Smectite Clays from MSL SAM Analyses of Mudstone at Yellowknife Bay, Gale Crater, Mars

    NASA Technical Reports Server (NTRS)

    McAdam, Amy; Franz, Heather; Mahaffy, Paul R.; Eigenbrode, Jennifer L.; Stern, Jennifer C.; Brunner, Anna; Archer, Paul Douglas; Ming, Douglas W.; Morris, Richard V.; Atreya, Sushil K.

    2013-01-01

    Drilled samples of mudstone from the Sheepbed unit at Yellowknife Bay were analyzed by MSL instruments including the Sample Analysis at Mars (SAM) and Chemistry and Mineralogy (CheMin) instruments in MSL's Analytical Laboratory. CheMin analyses revealed the first in situ X-ray diffraction based evidence of clay minerals on Mars, which are likely trioctahedral smectites (e.g., saponite) and comprise approx 20% of the mudstone sample (e.g., Bristow et al., this meeting). SAM analyses, which heated the mudstone samples to 1000 C and monitored volatiles evolved to perform in situ evolved gas analysis mass spectrometry (EGA-MS), resulted in a H2O trace exhibiting a wide evolution at temperatures < 500 C, and an evolution peak at higher temperatures near approx 750 C. The low temperature H2O evolution has many potential contributors, including adsorbed H2O, smectite interlayer H2O, and structural H2O/OH from bassanite and akaganeite (identified by CheMin) and H2O/OH from amorphous phases in the sample. The high temperature H2O is consistent with the evolution of H2O from the dehydroxylation of the smectite clay mineral. Comparison to EGA-MS data collected under SAM-like conditions on a variety of clay mineral reference materials indicate that a trioctahedral smectite, such as saponite, is most consistent with the high temperature H2O evolution observed. There may also be SAM EGA-MS evidence for a small high temperature H2O evolution from scoop samples from the Yellowknife Bay Rocknest sand shadow bedform. As in the mudstone samples, this evolution may indicate the detection of smectite clays, and the idea that minor clays may be present in Rocknest materials that could be expected to be at least partially derived from local sources is reasonable. But, because smectite clays were not definitively observed in CheMin analyses of Rocknest materials, they must be present at much lower abundances than the approx 20% observed in the mudstone samples. This potential detection

  2. CO2 adsorption isotherm on clay minerals and the CO2 accessibility into the clay interlayer

    NASA Astrophysics Data System (ADS)

    Gensterblum, Yves; Bertier, Pieter; Busch, Andreas; Rother, Gernot; Krooß, Bernhard

    2013-04-01

    Large-scale CO2 storage in porous rock formations at 1-3 km depth is seen as a global warming mitigation strategy. In this process, CO2 is separated from the flue gas of coal or gas power plants, compressed, and pumped into porous subsurface reservoirs with overlying caprocks (seals). Good seals are mechanically and chemically stable caprocks with low porosity and permeability. They prevent leakage of buoyant CO2 from the reservoir. Caprocks are generally comprised of thick layers of shale, and thus mainly consist of clay minerals. These clays can be affected by CO2-induced processes, such as swelling or dissolution. The interactions of CO2 with clay minerals in shales are at present poorly understood. Sorption measurements in combination scattering techniques could provide fundamental insight into the mechanisms governing CO2-clay interaction. Volumetric sorption techniques have assessed the sorption of supercritical CO2 onto coal (Gensterblum et al., 2010; Gensterblum et al., 2009), porous silica (Rother et al., 2012a) and clays as a means of exploring the potential of large-scale storage of anthropogenic CO2 in geological reservoirs (Busch et al., 2008). On different clay minerals and shales, positive values of excess sorption were measured at gas pressures up to 6 MPa, where the interfacial fluid is assumed to be denser than the bulk fluid. However, zero and negative values were obtained at higher densities, which suggests the adsorbed fluid becomes equal to and eventually less dense than the corresponding bulk fluid, or that the clay minerals expand on CO2 charging. Using a combination of neutron diffraction and excess sorption measurements, we recently deduced the interlayer density of scCO2 in Na-montmorillonite clay in its single-layer hydration state (Rother et al., 2012b), and confirmed its low density, as well as the expansion of the basal spacings. We performed neutron diffraction experiments at the FRMII diffractometer on smectite, kaolinite and illite

  3. Glowing clay: Real time tracing using a suite of novel clay based fluorescent tracers

    NASA Astrophysics Data System (ADS)

    Hardy, Robert; Quinton, John; Pates, Jackie; Coogan, Mike

    2015-04-01

    Clay is one of the most mobile fractions of soil due to its small particle size. It is also known to sorb many chemicals, such as nutrients (notably phosphorus), agrochemicals and heavy metals. The movement of clay is therefore linked with the transport and fate of these substances. A novel fluorescent clay tracing suite has been produced, together with an imaging technique. This suite consists of qualitative clay tracers, using rhodamine based fluorophores, and quantitative clay tracers, using metal based fluorophores. Efforts have also been made to allow integration of commercially available tracers, which are silt and sand sized. The clay tracers exploit the high affinity that montmorillonite has for Rhodamine B and Ru(bpy)3. This allows for an extremely thin layer of the fluorophore to be sorbed onto the clay's surface, in much that same way as materials in the natural environment will bind to clay. The tracer that is produced retains key chemical and physical properties of clay, such as size, shape and density. The retention of these micro-properties results in the retention of macro-properties, such as tendency to aggregate and cracking on drying. Imaging techniques have been developed to analyse these tracers. The imaging system uses diffused laser light to excite the tracer and a modified DSLR camera to image the soil surface. The images have been compiled into a time lapse video showing the movement of clay over the course of a rainfall event. This is the first time that the quantitative movement of clay has been recorded over a soil surface in real time. 4D data can be extracted from the images allowing the spatial location and intensity of tracer to be monitored over time, with mm precision and on the timescale of seconds. As the system can also work with a commercial tracer it is possible to investigate the movement of particles of almost any size and over a range of scales from soil box to hillside. This allows users to access this technique without

  4. Can Reaction Mechanisms Be Proven?

    NASA Astrophysics Data System (ADS)

    Buskirk, Allen; Baradaran, Hediyeh

    2009-05-01

    "Can Reaction Mechanisms Be Proven?" generated spirited responses from its reviewers. The reviews were approximately evenly divided, and all were of very high quality. The authors agreed with the editor’s proposal that the reviewers convert their reviews into rebuttals or affirmations of the authors’ position for publication along with the article, which has been revised based on the reviews. Most agreed to such a process and their comments appear here. We hope that publication of this paper and well-reasoned rebuttals such as those provided here will initiate a wide-ranging discussion. JCE will provide an online forum for further discussion of the issue. Our hope is that both faculty and students will contribute their opinions and ideas to this discussion. See Reviewer Comments: Brown Lewis Yoon Wade

  5. Painting with Clay: A Study of the Masters

    ERIC Educational Resources Information Center

    Skophammer, Karen

    2010-01-01

    Plasticine clay is a bendable material that is easily manipulated by students of all ages. It is a great material to work with because it does not dry out from day to day, so high-school students can work on an extended project. They do not have to worry about the clay drying and cracking, and the entire work of art does not have to be completed…

  6. Painting with Clay: A Study of the Masters

    ERIC Educational Resources Information Center

    Skophammer, Karen

    2010-01-01

    Plasticine clay is a bendable material that is easily manipulated by students of all ages. It is a great material to work with because it does not dry out from day to day, so high-school students can work on an extended project. They do not have to worry about the clay drying and cracking, and the entire work of art does not have to be completed…

  7. Software and Workflow Provenance: Documenting Scientific Methods

    NASA Astrophysics Data System (ADS)

    Gil, Y.

    2016-12-01

    While major effort has been devoted to data provenance, the provenance of software and workflows is not as well understood. Software artifacts have their own provenance in terms of how they were created, what theories or models are behind them, and how they are derived from earlier versions or prior implementations. Workflows also evolve to reflect changes in science methods, as they are extended or assumptions lifted. These provenance records may be created separately from the provenance records of the articles themselves, but are needed to fully document the provenance of new scientific results in the published record. These are issues that the EarthCube OntoSoft project and the Geoscience Papers of the Future initiative are exploring. This presentation will discuss the requirements for capturing software and workflow provenance, the integration of those provenance records with provenance of new results in an article, and the integration of data provenance with software and workflow provenance. The presentation will also discuss how provenance records can support automated credit assignment, so that the explicit provenance records of the results in a paper can be automatically analyzed to extract credit to the software and workflows used to generate the results.

  8. Geotechnical Characterization of Mined Clay from Appalachian Ohio: Challenges and Implications for the Clay Mining Industry

    PubMed Central

    Moran, Anthony R.; Hettiarachchi, Hiroshan

    2011-01-01

    Clayey soil found in coal mines in Appalachian Ohio is often sold to landfills for constructing Recompacted Soil Liners (RSL) in landfills. Since clayey soils possess low hydraulic conductivity, the suitability of mined clay for RSL in Ohio is first assessed by determining its clay content. When soil samples are tested in a laboratory, the same engineering properties are typically expected for the soils originated from the same source, provided that the testing techniques applied are standard, but mined clay from Appalachian Ohio has shown drastic differences in particle size distribution depending on the sampling and/or laboratory processing methods. Sometimes more than a 10 percent decrease in the clay content is observed in the samples collected at the stockpiles, compared to those collected through reverse circulation drilling. This discrepancy poses a challenge to geotechnical engineers who work on the prequalification process of RSL material as it can result in misleading estimates of the hydraulic conductivity of the samples. This paper describes a laboratory investigation conducted on mined clay from Appalachian Ohio to determine how and why the standard sampling and/or processing methods can affect the grain-size distributions. The variation in the clay content was determined to be due to heavy concentrations of shale fragments in the clayey soils. It was also concluded that, in order to obtain reliable grain size distributions from the samples collected at a stockpile of mined clay, the material needs to be processed using a soil grinder. Otherwise, the samples should be collected through drilling. PMID:21845150

  9. Mud peeling and horizontal crack formation in drying clays

    NASA Astrophysics Data System (ADS)

    Style, Robert W.; Peppin, Stephen S. L.; Cocks, Alan C. F.

    2011-03-01

    Mud peeling is a common phenomenon whereby horizontal cracks propagate parallel to the surface of a drying clay. Differential stresses then cause the layer of clay above the crack to curl up to form a mud peel. By treating the clay as a poroelastic solid, we analyze the peeling phenomenon and show that it is caused by the gradient in tensile stress at the surface of the clay, analogously to the spalling of thermoelastic materials. For a constant water evaporation rate at the clay surface we derive equations for the depth of peeling and the time of peeling as functions of the evaporation rate. Our model predicts a simple relationship between the radius of curvature of a mud peel and the depth of peeling. The model predictions are in agreement with the available experimental data.

  10. Organic/Inorganic Hybrid Polymer/Clay Nanocomposites

    NASA Technical Reports Server (NTRS)

    Park, Cheol; Connell, John W.; Smith, Joseph G., Jr.

    2003-01-01

    A novel class of polymer/clay nanocomposites has been invented in an attempt to develop transparent, lightweight, durable materials for a variety of aerospace applications. As their name suggests, polymer/ clay nanocomposites comprise organic/ inorganic hybrid polymer matrices containing platelet-shaped clay particles that have sizes of the order of a few nanometers thick and several hundred nanometers long. Partly because of their high aspect ratios and high surface areas, the clay particles, if properly dispersed in the polymer matrix at a loading level of 1 to 5 weight percent, impart unique combinations of physical and chemical properties that make these nanocomposites attractive for making films and coatings for a variety of industrial applications. Relative to the unmodified polymer, the polymer/ clay nanocomposites may exhibit improvements in strength, modulus, and toughness; tear, radiation, and fire resistance; and lower thermal expansion and permeability to gases while retaining a high degree of optical transparency.

  11. Unsaturated properties for non-Darcian water flow in clay

    NASA Astrophysics Data System (ADS)

    Liu, Hui-Hai; Li, Lianchong; Birkholzer, Jens

    2012-04-01

    SummaryClay rock formations, and compacted clay (e.g., bentonite) used as backfill within disposal drifts, have been considered as natural and engineered barriers, respectively, for isolating high-level nuclear wastes in mined geologic repositories. Accurately modeling unsaturated flow in those clay materials is important for assessing the performance of a geological repository. While the non-Darcian behavior of water flow in clay materials has been demonstrated in the literature, a systematic study of modeling unsaturated non-Darcian flow is still lacking. Based on a hypothesis that pore water in clay becomes non-Newtonian as a result of water-clay interaction, we propose new constitutive relationships for unsaturated flow, including a relationship between water flux and hydraulic gradient and those among capillary pressure, water saturation, and hydraulic conductivity. An evaluation based on a set of laboratory experimental observations supports the usefulness of the proposed relationships. More experimental studies are desirable for further confirming the non-Newtonian water flow behavior in clay materials and evaluating the proposed relationships.

  12. Toxicological evaluation of clay minerals and derived nanocomposites: a review.

    PubMed

    Maisanaba, Sara; Pichardo, Silvia; Puerto, María; Gutiérrez-Praena, Daniel; Cameán, Ana M; Jos, Angeles

    2015-04-01

    Clays and clay minerals are widely used in many facets of our society. This review addresses the main clays of each phyllosilicate groups, namely, kaolinite, montmorillonite (Mt) and sepiolite, placing special emphasis on Mt and kaolinite, which are the clays that are more frequently used in food packaging, one of the applications that are currently exhibiting higher development. The improvements in the composite materials obtained from clays and polymeric matrices are remarkable and well known, but the potential toxicological effects of unmodified or modified clay minerals and derived nanocomposites are currently being investigated with increased interest. In this sense, this work focused on a review of the published reports related to the analysis of the toxicological profile of commercial and novel modified clays and derived nanocomposites. An exhaustive review of the main in vitro and in vivo toxicological studies, antimicrobial activity assessments, and the human and environmental impacts of clays and derived nanocomposites was performed. From the analysis of the scientific literature different conclusions can be derived. Thus, in vitro studies suggest that clays in general induce cytotoxicity (with dependence on the clay, concentration, experimental system, etc.) with different underlying mechanisms such as necrosis/apoptosis, oxidative stress or genotoxicity. However, most of in vivo experiments performed in rodents showed no clear evidences of systemic toxicity even at doses of 5000mg/kg. Regarding to humans, pulmonary exposure is the most frequent, and although clays are usually mixed with other minerals, they have been reported to induce pneumoconiosis per se. Oral exposure is also common both intentionally and unintentionally. Although they do not show a high toxicity through this pathway, toxic effects could be induced due to the increased or reduced exposure to mineral elements. Finally, there are few studies about the effects of clay minerals on

  13. The surface modification of clay particles by RF plasma technique

    NASA Astrophysics Data System (ADS)

    Lee, Sang-Keol

    In this study, the surface coatings of ball clay, organoclay and exfoliated clay prepared by sol-gel process were done by RF plasma polymerization to improve the surface activity of the clay filler. Characterization of the above plasma-treated clays has been carried out by various techniques. The effects of plasma-treated clays as substitute of carbon black in styrene-butadiene rubber (SBR) and ethylene-propylene-diene monomer (EPDM) on the curing and mechanical properties were investigated. After plasma treatment, the tensile properties of organo and exfoliated clay were not unsatisfactory to that of carbon black filler system. Moreover, only 10 phr filler loading of plasma-treated organoclay in EPDM vulcanizates showed better results than 40 phr filler loading of carbon black in EPDM vulcanizates. The main objective of this study was to verify the applicability of the plasma technique for modifying clay surfaces for their use in the tire manufacturing industry. Another purpose was to reveal the advantage of the plasma technique used to obtain modified-clay and improved properties that those materials can display.

  14. PROX: Approximated Summarization of Data Provenance

    PubMed Central

    Ainy, Eleanor; Bourhis, Pierre; Davidson, Susan B.; Deutch, Daniel; Milo, Tova

    2016-01-01

    Many modern applications involve collecting large amounts of data from multiple sources, and then aggregating and manipulating it in intricate ways. The complexity of such applications, combined with the size of the collected data, makes it difficult to understand the application logic and how information was derived. Data provenance has been proven helpful in this respect in different contexts; however, maintaining and presenting the full and exact provenance may be infeasible, due to its size and complex structure. For that reason, we introduce the notion of approximated summarized provenance, where we seek a compact representation of the provenance at the possible cost of information loss. Based on this notion, we have developed PROX, a system for the management, presentation and use of data provenance for complex applications. We propose to demonstrate PROX in the context of a movies rating crowd-sourcing system, letting participants view provenance summarization and use it to gain insights on the application and its underlying data. PMID:27570843

  15. PROX: Approximated Summarization of Data Provenance.

    PubMed

    Ainy, Eleanor; Bourhis, Pierre; Davidson, Susan B; Deutch, Daniel; Milo, Tova

    2016-03-01

    Many modern applications involve collecting large amounts of data from multiple sources, and then aggregating and manipulating it in intricate ways. The complexity of such applications, combined with the size of the collected data, makes it difficult to understand the application logic and how information was derived. Data provenance has been proven helpful in this respect in different contexts; however, maintaining and presenting the full and exact provenance may be infeasible, due to its size and complex structure. For that reason, we introduce the notion of approximated summarized provenance, where we seek a compact representation of the provenance at the possible cost of information loss. Based on this notion, we have developed PROX, a system for the management, presentation and use of data provenance for complex applications. We propose to demonstrate PROX in the context of a movies rating crowd-sourcing system, letting participants view provenance summarization and use it to gain insights on the application and its underlying data.

  16. Geochemically tracking provenance changes in marine sediment from the South Pacific Gyre throughout the Cenozoic

    NASA Astrophysics Data System (ADS)

    Dunlea, A. G.; Murray, R. W.; Sauvage, J.; Spivack, A. J.; Harris, R. N.; D'Hondt, S. L.

    2012-12-01

    The South Pacific Gyre (SPG), characterized by extremely slow sedimentation rates, is the world's largest oceanic desert. The little eolian dust from continents in the Southern Hemisphere must traverse great distances to reach the SPG, and the ultra-oligotrophic waters minimize the biogenic flux of sediment to the seafloor. However sparse, the pelagic sediment that is ultimately found on the seafloor retains a chemical record that can be used to trace its origin. Using cores from Integrated Ocean Drilling Program Expedition 329, we trace downcore fluctuations in major, trace, and rare earth element (REE) composition and flux to yield clues to the geological, chemical, and biological evolution of the SPG throughout the Cenozoic. The shipboard scientific party generally described the completely oxic, brown pelagic clays recovered during Exp. 329 as zeolitic metalliferous clay. The homogenous, very fine-grained nature of these sediments speaks to the challenges we face in resolving eolian detrital material ("dust"), fine-grained ash (commonly altered), and authigenic aluminosilicates from one another. Based on ICP-ES and ICP-MS analyses followed by multivariate statistical treatments, we are developing chemical records from a number of sites located throughout the SPG. Building on earlier work at DSDP Site 596 (Zhou and Kyte, 1992, Paleocean., 7, 441-465), and based on backtrack paths from 100 Ma forward, we are working to construct a regionally and temporally continuous paleoclimatological history of the SPG. Preliminary La-Th-Sc concentrations from Sites U1367, U1368, and U1369 show a distinct authigenic influence, but several refractory elements retain their original provenance signature. Sediment ages are constrained using a constant-Co model, based on the geochemically similar work that Zhou and Kyte (1992) performed in the SPG. REE concentrations normalized to post-archean average shale (PAAS) reveal a negative Ce anomaly that becomes more pronounced closer to

  17. A general evaluation of the frequency distribution of clay and associated minerals in the alluvial soils of ceylon

    USGS Publications Warehouse

    Herath, J.W.; Grimshaw, R.W.

    1971-01-01

    Clay mineral analyses were made of several alluvial clay materials from Ceylon. These studies show that the soil materials can be divided into 3 clay mineral provinces on the basis of the frequency distribution of clay and associated minerals. The provinces closely follow the climatic divisions. The characteristic feature of this classification is the progressive development of gibbsite from Dry to Wet Zone areas. Gibbsite has been used as a reliable indicator mineral. ?? 1971.

  18. Clay mineralogy of the Cretaceous-Tertiary boundary clay. [in search for asteroid ejecta

    NASA Technical Reports Server (NTRS)

    Rampino, M. R.; Reynolds, R. C.

    1983-01-01

    Cretaceous-Tertiary boundary layer clay samples from four localities were subjected to analyses which imply that they are neither mineralogically exotic nor distinct from locally derived clays above and below the boundary. The anomalous iridium-rich ejecta component predicted by the asteroid impact scenario of Alvarez et al (1980) was not detected. It is proposed that volcanic material be considered as an explanation of the geochemical anomalies of the Cretaceous-Tertiary boundary. A model which involves a period of intense volcanism at the end of the Cretaceous would generate a variety of climatic and biological effects consonant with the geologic history of that period.

  19. Clay mineralogy of the Cretaceous-Tertiary boundary clay. [in search for asteroid ejecta

    NASA Technical Reports Server (NTRS)

    Rampino, M. R.; Reynolds, R. C.

    1983-01-01

    Cretaceous-Tertiary boundary layer clay samples from four localities were subjected to analyses which imply that they are neither mineralogically exotic nor distinct from locally derived clays above and below the boundary. The anomalous iridium-rich ejecta component predicted by the asteroid impact scenario of Alvarez et al (1980) was not detected. It is proposed that volcanic material be considered as an explanation of the geochemical anomalies of the Cretaceous-Tertiary boundary. A model which involves a period of intense volcanism at the end of the Cretaceous would generate a variety of climatic and biological effects consonant with the geologic history of that period.

  20. Tracking Provenance in ORNL's Flexible Research Platforms

    SciTech Connect

    Hensley, Zachary P; Sanyal, Jibonananda; New, Joshua Ryan

    2013-08-01

    Provenance is dened as information about the origin of objects, a concept that applies to both physical and digital objects and often overlaps both. The use of provenance in systems designed for research is an important but forgotten feature. Provenance allows for proper and exact tracking of information, its use, its lineage, its derivations and other metadata that are important for correctly adhering to the scien- tic method. In our project's prescribed use of provenance, researchers can determine detailed information about the use of sensor data in their experiments on ORNL's Flexible Research Platforms (FRPs). Our project's provenance system, Provenance Data Management System (ProvDMS), tracks information starting with the creation of information by an FRP sensor. The system determines station information, sensor information, and sensor channel information. The system allows researchers to derive generations of experiments from the sensor data and tracks their hierarchical flow. Key points can be seen in the history of the information as part of the information's workflow. The concept of provenance and its usage in science is relatively new and while used in other cases around the world, our project's provenance diers in a key area. To keep track of provenance, most systems must be designed or redesigned around the new provenance system. Our system is designed as a cohesive but sepa- rate entity and allows for researchers to continue using their own methods of analysis without being constrained in their ways in order to track the provenance. We have designed ProvDMS using a lightweight provenance library, Core Provenance Library (CPL) v.6 In addition to keeping track of sensor data experiments and its provenance, ProvDMS also provides a web-enabled visualization of the inheritance.

  1. Bauxite washing for the removal of clay

    NASA Astrophysics Data System (ADS)

    Ahmad, Ishaq; Hartge, Ernst-Ulrich; Werther, Joachim; Wischnewski, Reiner

    2014-11-01

    Clay impurities associated with bauxite negatively affect the Bayer process for alumina production. These impurities should be removed as far as possible by a beneficiation technique before the ore is used as feed for the Bayer process. In this current investigation, bauxite washing was conducted in the laboratory. Bauxite washing is a physical process that causes the disintegration and deagglomeration of the clay matrix, and bauxite is liberated from the clay (mainly rich in silica). Subsequently, separation occurs with the assistance of wet screening at a predetermined cut size. Three techniques were investigated in the laboratory: drum washing, water-jet washing, and ultrasonic washing. Various operating parameters were investigated for drum washing and water-jet washing, including materials retention time, drum rotation speed, solid concentration, water-jet spray duration, pressure, and height. We concluded that the retention time of bauxite inside the drum at a solid concentration of 55wt% and a drum rotation speed of 31 r/min is the dominant parameter for the removal of clay from the bauxite surface.

  2. Effect of clays on the fire-retardant properties of a polyethylenic copolymer containing intumescent formulation

    PubMed Central

    Ribeiro, Simone P S; Estevão, Luciana R M; Nascimento, Regina S V

    2008-01-01

    Organophilic clay particles were added to a standard intumescent formulation and, since the role of clay expansion or intercalation is still a matter of much controversy, several clays with varying degrees of interlayer distances were evaluated. The composites were obtained by blending the nanostructured clay and the intumescent system with a polyethylenic copolymer. The flame-retardant properties of the materials were evaluated by the limiting oxygen index (LOI), the UL-94 rating and thermogravimetric analysis (TGA). The results showed that the addition of highly expanded clays to the ammonium polyphosphate and pentaerythritol formulation does not significantly increase the flame retardancy of the mixture, when measured by the LOI and UL-94. However, when clays with smaller basal distances were added to the intumescent formulation, a synergistic effect was observed. In contrast, the simple addition of clays to the copolymer, without the intumescent formulation, did not increase the fire retardance of the materials. PMID:27877975

  3. Effect of clays on the fire-retardant properties of a polyethylenic copolymer containing intumescent formulation.

    PubMed

    Ribeiro, Simone P S; Estevão, Luciana R M; Nascimento, Regina S V

    2008-04-01

    Organophilic clay particles were added to a standard intumescent formulation and, since the role of clay expansion or intercalation is still a matter of much controversy, several clays with varying degrees of interlayer distances were evaluated. The composites were obtained by blending the nanostructured clay and the intumescent system with a polyethylenic copolymer. The flame-retardant properties of the materials were evaluated by the limiting oxygen index (LOI), the UL-94 rating and thermogravimetric analysis (TGA). The results showed that the addition of highly expanded clays to the ammonium polyphosphate and pentaerythritol formulation does not significantly increase the flame retardancy of the mixture, when measured by the LOI and UL-94. However, when clays with smaller basal distances were added to the intumescent formulation, a synergistic effect was observed. In contrast, the simple addition of clays to the copolymer, without the intumescent formulation, did not increase the fire retardance of the materials.

  4. Iodide Sorption to Clays and the Relationship to Surface Charge and Clay Texture - 12356

    SciTech Connect

    Miller, Andrew; Kruichiak, Jessica; Tellez, Hernesto; Wang, Yifeng

    2012-07-01

    Iodine is assumed to behave conservatively in clay barriers around nuclear waste repositories and in natural sediments. Batch experiments tend to show little to no sorption, while in column experiments iodine is often retarded relative to tritiated water. Current surface complexation theory cannot account for negatively charged ion sorption to a negatively charged clay particle. Surface protonation and iodide sorption to clay minerals were examined using surface titrations and batch sorption experiments with a suite of clay minerals. Surface titrations were completed spanning a range of both pH values and ionic strengths. For reference, similar titrations were performed on pure forms of an Al-O powder. The titration curves were deconvoluted to attain the pKa distribution for each material at each ionic strength. The pKa distribution for the Al-O shows two distinct peaks at 4.8 and 7.5, which are invariant with ionic strength. The pKa distribution of clays was highly variable between the different minerals and as a function of ionic strength. Iodide sorption experiments were completed at high solid:solution ratios to exacerbate sorption properties. Palygorskite and kaolinite had the highest amount of iodide sorption and montmorillonite had the least. (authors)

  5. Evaluating sand and clay models: do rheological differences matter?

    NASA Astrophysics Data System (ADS)

    Eisenstadt, Gloria; Sims, Darrell

    2005-08-01

    Dry sand and wet clay are the most frequently used materials for physical modeling of brittle deformation. We present a series of experiments that shows when the two materials can be used interchangeably, document the differences in deformation patterns and discuss how best to evaluate and apply results of physical models. Extension and shortening produce similar large-scale deformation patterns in dry sand and wet clay models, indicating that the two materials can be used interchangeably for analysis of gross deformation geometries. There are subtle deformation features that are significantly different: (1) fault propagation and fault linkage; (2) fault width, spacing and displacement; (3) extent of deformation zone; and (4) amount of folding vs. faulting. These differences are primarily due to the lower cohesion of sand and its larger grain size. If these features are of interest, the best practice would be to repeat the experiments with more than one material to ensure that rheological differences are not biasing results. Dry sand and wet clay produce very different results in inversion models; almost all faults are reactivated in wet clay, and few, if any, are significantly reactivated in sand models. Fault reactivation is attributed to high fluid pressure along the fault zone in the wet clay, a situation that may be analogous to many rocks. Sand inversion models may be best applied to areas where most faults experience little to no reactivation, while clay models best fit areas where most pre-existing normal faults are reactivated.

  6. Field trip guidebook on environmental impact of clays along the upper Texas coast

    NASA Technical Reports Server (NTRS)

    Garcia, Theron D.; Ming, Douglas W.; Tuck, Lisa Kay

    1991-01-01

    The field trip was prepared to provide an opportunity to see first hand some the environmental hazards associated with clays in the Houston, Texas area. Because of the very high clay content in area soils and underlying Beaumont Formation clay, Houston is a fitting location to host the Clay Mineral Society. Examinations were made of (1) expansive soils, (2) subsidence and surface faulting, and (3) a landfill located southeast of Houston at the Gulf Coast Waste Disposal Authority where clay is part of the liner material.

  7. Mechanism of fatigue failure of clay-epoxy nanocomposites.

    PubMed

    Juwono, Ariadne; Edward, Graham

    2006-12-01

    This work investigates the fatigue behaviour and the mechanism of fatigue failure of an epoxy resin with a dispersion of modified layered silicates in the polymer matrix. The fatigue properties are very important for structural application of nanocomposite materials. Clay-epoxy nanocomposites were successfully synthesized with a commercially available 1-Methylimidazole curing agent. The XRD and TEM findings demonstrated a pattern of clay morphology typically found in nanocomposite systems. The fatigue performance and fatigue failure mechanism of the clay-epoxy materials were studied under repetitive bending loads. The results showed that the fatigue life of filled epoxy improved significantly at strain amplitudes below a threshold value. The E-SEM observations of the epoxy and the clay-epoxy fracture surfaces showed different patterns. In conclusion, the addition of silicate strongly determines the fracture mechanism and enhances the fatigue performance.

  8. Coalification by clay-catalyzed oligomerization of plant monomers

    SciTech Connect

    Orchin, M.; Wilson, R.M.

    1990-01-01

    The main objective of this research program is to devise laboratory methods to mimic the processes by which plants synthesize lignans, lignins and the processes by which these materials are transformed further by geochemical reactions catalyzed by certain clays to coal-like materials. We believe that the radical cation Diels-Alder reaction is one of the principal routes which transforms simple plant materials to coal-like substances and that such reactions may be catalyzed by clays that occur in the environment of the decaying plant materials. Progress is described.

  9. Distinguishing Provenance Equivalence of Earth Science Data

    NASA Technical Reports Server (NTRS)

    Tilmes, Curt; Yesha, Ye; Halem, M.

    2010-01-01

    Reproducibility of scientific research relies on accurate and precise citation of data and the provenance of that data. Earth science data are often the result of applying complex data transformation and analysis workflows to vast quantities of data. Provenance information of data processing is used for a variety of purposes, including understanding the process and auditing as well as reproducibility. Certain provenance information is essential for producing scientifically equivalent data. Capturing and representing that provenance information and assigning identifiers suitable for precisely distinguishing data granules and datasets is needed for accurate comparisons. This paper discusses scientific equivalence and essential provenance for scientific reproducibility. We use the example of an operational earth science data processing system to illustrate the application of the technique of cascading digital signatures or hash chains to precisely identify sets of granules and as provenance equivalence identifiers to distinguish data made in an an equivalent manner.

  10. Molecular interactions alter clay and polymer structure in polymer clay nanocomposites.

    PubMed

    Sikdar, Debashis; Katti, Kalpana S; Katti, Dinesh R

    2008-04-01

    OMMTs with three different organic modifiers further confirm the change in structural orientation of silica tetrahedra of OMMTs by organic modifiers. Thus, from our work it is evident that organic modifiers have significant influence on the structure of polymer and clay in PCNs. It appears that in nanocomposites, in addition to strong interactions at interfaces between constituents, the structure of different phases (clay and polymer) of PCN are also altered, which does not occur in conventional composite materials. Thus, the mechanisms governing composite action in nanocomposites are quite different from that of conventional macro composites.

  11. Deformation mechanisms in experimentally deformed Boom Clay

    NASA Astrophysics Data System (ADS)

    Desbois, Guillaume; Schuck, Bernhard; Urai, Janos

    2016-04-01

    Bulk mechanical and transport properties of reference claystones for deep disposal of radioactive waste have been investigated since many years but little is known about microscale deformation mechanisms because accessing the relevant microstructure in these soft, very fine-grained, low permeable and low porous materials remains difficult. Recent development of ion beam polishing methods to prepare high quality damage free surfaces for scanning electron microscope (SEM) is opening new fields of microstructural investigation in claystones towards a better understanding of the deformation behavior transitional between rocks and soils. We present results of Boom Clay deformed in a triaxial cell in a consolidated - undrained test at a confining pressure of 0.375 MPa (i.e. close to natural value), with σ1 perpendicular to the bedding. Experiments stopped at 20 % strain. As a first approximation, the plasticity of the sample can be described by a Mohr-Coulomb type failure envelope with a coefficient of cohesion C = 0.117 MPa and an internal friction angle ϕ = 18.7°. After deformation test, the bulk sample shows a shear zone at an angle of about 35° from the vertical with an offset of about 5 mm. We used the "Lamipeel" method that allows producing a permanent absolutely plane and large size etched micro relief-replica in order to localize and to document the shear zone at the scale of the deformed core. High-resolution imaging of microstructures was mostly done by using the BIB-SEM method on key-regions identified after the "Lamipeel" method. Detailed BIB-SEM investigations of shear zones show the following: the boundaries between the shear zone and the host rock are sharp, clay aggregates and clastic grains are strongly reoriented parallel to the shear direction, and the porosity is significantly reduced in the shear zone and the grain size is smaller in the shear zone than in the host rock but there is no evidence for broken grains. Comparison of microstructures

  12. Liver fluke isolates: a question of provenance.

    PubMed

    Fairweather, I

    2011-02-28

    A survey of literature on experimental infections with the liver fluke, Fasciola hepatica published between 2005 and 2009 has revealed a general lack of information on where fluke material (i.e. metacercariae) was sourced from. Even less information was given on the drug status of the fluke isolate used, which is a particular concern for those studies that involved anthelmintics. In these two respects, information on the liver fluke lags far behind that for nematodes, where such information is given almost as a matter of course. Of additional concern is that, at times, information about the source and drug history of fluke isolates was incorrect. The overall aim of the review is to demonstrate why it is important to provide as much information as possible on what fluke material is being used. It also attempts to correct some of the errors in the literature and gather together what information is available about the provenance of those isolates that have been used in recent experimental studies. Copyright © 2010 Elsevier B.V. All rights reserved.

  13. Leveraging Data Provenance to Enhance Cyber Resilience

    DTIC Science & Technology

    2016-11-01

    system perspective [6], [21], [27], [26], [30]. System layer provenance also offers gapless descriptions of user space activity, effectively making...every application that runs on the system provenance-aware. Unfortunately, the semantic gap between kernel and user space can make system provenance...controversy [31]. An overview of the LPM architecture is shown in Figure 1. LPM instruments the Linux kernel with a 178 dedicated user space kernel space

  14. Special Issue: The First Provenance Challenge

    SciTech Connect

    Moreau, Luc; Ludaescher, Bertram T.; Altintas, Ilkay; Barga, Roger S.; Bowers, Shawn; Callahan, Steven P.; Chin, George; Clifford, Ben; Cohen, Shirley; Cohen-Boulakia, Sarah; Davidson, Susan; Deelman, Ewa; digiampietri, Luciano; Foster, Ian T.; Freire, Juliana; Frew, James; Futrelle, Joe; Gibson, Tara D.; Gil, Yolanda; Goble, Carole; Golbeck, Jennifer; Groth, Paul; Holland, David A.; Jiang, Sheng; Kim, Jihie; Koop, David; Krenek, Ales; McPhillips, Timothy; Mehta, Gaurang; Miles, Simon; Metzger, Dominic; Munroe, Steve; Myers, James D.; Plale, Beth A.; Podhorszki, norbert; Ratnakar, Varun; Emanuele , Santos; scheidegger, Carlos E.; Schuchardt, Karen L.; Seltzer, Margo I.; Simmhan, Yogesh L.; Claudio, Silva T.; Slaughter, Peter; Stephan, Eric G.; Stevens, Robert; Turi, Daniele; Vo, Huy T.; Wilde, Mike J.; Zhao, Jun; Zhao, Yong

    2008-04-01

    The first Provenance Challenge was set up in order to provide a forum for the community to help understand the capabilities of different provenance systems and the expressiveness of their provenance representations. To this end, a Functional Magnetic Resonance Imaging workflow was defined, which participants had to either simulate or run in order to produce some provenance representation, from which a set of identified queries had to be implemented and executed. Sixteen teams responded to the challenge, and submitted their inputs. In this paper, we present the challenge workflow and queries, and summarise the participants contributions.

  15. Research on provenance of MVT Pb-Zn deposits

    NASA Astrophysics Data System (ADS)

    Liu, Huiguo

    2017-06-01

    Based on previous research materials, provenance of MVT Pb-Zn deposits are explored. The results suggest that in China, MVT Pb-Zn ores form when deep met allogenic materials are transported to shallow zones through large deep zones and taken away after they are leached by fluids. All typical MVT Pb-Zn ores present features of crust sources all over the world.

  16. Clay-Enriched Silk Biomaterials for Bone Formation

    PubMed Central

    Mieszawska, Aneta J.; Llamas, Jabier Gallego; Vaiana, Christopher A.; Kadakia, Madhavi P.; Naik, Rajesh R.; Kaplan, David L.

    2011-01-01

    The formation of silk protein/clay composite biomaterials for bone tissue formation is described. Silk fibroin serves as an organic scaffolding material offering mechanical stability suitable for bone specific uses. Clay montmorillonite (Cloisite ® Na+) and sodium silicate are sources of osteoinductive silica-rich inorganic species, analogous to bioactive bioglass-like bone repair biomaterial systems. Different clay particle-silk composite biomaterial films were compared to silk films doped with sodium silicate as controls for support of human bone marrow derived mesenchymal stem cells (hMSCs) in osteogenic culture. The cells adhered and proliferated on the silk/clay composites over two weeks. Quantitative real-time RT-PCR analysis revealed increased transcript levels for alkaline phosphatase (ALP), bone sialoprotein (BSP), and collagen type 1 (Col I) osteogenic markers in the cells cultured on the silk/clay films in comparison to the controls. Early evidence for bone formation based on collagen deposition at the cell-biomaterial interface was also found, with more collagen observed for the silk films with higher contents of clay particles. The data suggest that the silk/clay composite systems may be useful for further study toward bone regenerative needs. PMID:21549864

  17. Mineral resource of the Month: Clay

    USGS Publications Warehouse

    Virta, Robert L.

    2010-01-01

    Clays were one of the first mineral commodities used by people. Clay pottery has been found in archeological sites that are 12,000 years old, and clay figurines have been found in sites that are even older.

  18. Effects of shock metamorphism on clay mineralogy: Implications for remote sensing of martian clays

    NASA Astrophysics Data System (ADS)

    Michalski, J. R.; Glotch, T. D.; Friedlander, L.; Bish, D. L.; Sharp, T. G.; Dyar, M. D.

    2012-12-01

    One of the most important discoveries in recent exploration of Mars has been the detection of clay minerals within materials exhumed by meteor impact, which point to ancient subsurface alteration and possible habitable conditions at depth. These "crustal clays" occur within central peaks, ejecta, and uplifted rims of many large craters (Ehlmann et al., Nature 2011). The geologic context of phyllosilicates in these settings suggests that most of these deposits represent clays that formed in the subsurface and were later exhumed by impact, rather than clays that formed as a consequence of impact. Therefore, crustal clays exposed at the surface are likely to have experienced some effects of shock metamorphism and/or thermal alteration related to meteor impact. We are investigating the effects of shock metamorphism on the mineralogy of phyllosilicates in the laboratory. Purified, size-separated clay mineral samples were pressed into pellets to decrease internal porosity and were subsequently shocked using the Flat Plate Accelerator at NASA Johnson Space Center. Five minerals (nontronite, saponite, serpentine, chlorite, and kaolinite) were shocked to six pressure steps (10, 20, 25, 30, 35, and 40 GPa). The recovered, shocked samples are being analyzed by thermal infrared emission, visible/near-infrared reflectance, X-ray diffraction (XRD), Mossbauer spectroscopy, and transmission electron microscopy (TEM). Results thus far suggest that shock metamorphism has little effect on the structure or infrared signature of the clay minerals at pressures <20 GPa. One exception is the decrease in 3-D ordering in chlorite at 10 GPa, which steadily decreases until it is essentially lost at 30 GPa. At shock pressures of 20 GPa and higher, all minerals show evidence for broadening of the basal 001 reflection, indicative of progressive decrease in crystallite size. Above 30 GPa, the structures are intensely altered and by 40 GPa, most structural order is lost, based on both XRD and TEM

  19. Spectromicroscopy of Fe distributions in clay microcrystals

    SciTech Connect

    Grundl, T.; Cerasari, S.; Garcia, A.

    1997-04-01

    Clays are ubiquitous crystalline particles found in nature that are responsible for contributing to a wide range of chemical reactions in soils. The structure of these mineral particles changes when the particle is hydrated ({open_quotes}wet{close_quotes}), from that when it is dry. This makes a study of the microscopic distribution of chemical content of these nanocrystals difficult using standard techniques that require vacuum. In addition to large structural changes, it is likely that chemical changes accompany the drying process. As a result, spectroscopic measurements on dried clay particles may not accurately reflect the actual composition of the material as found in the environment. In this work, the authors extend the use of the ALS Spectromicroscopy Facility STXM to high spectral and spatial resolution studies of transition metal L-edges in environmental materials. The authors are studying mineral particles of montmorillonite, which is an Fe bearing clay which can be prepared with a wide distribution of Fe concentrations, and with Fe occupying different substitutional sites.

  20. Atomic Force Microscope Studies of Synthetic Clays

    NASA Astrophysics Data System (ADS)

    Piner, Richard; Ruoff, Rodney

    2003-03-01

    Clays are a class of compounds made up of small crystals of layered silicates. They are chemically and structurely similar to mica, but the individual crystals have lateral dimensions of 1 micron. Once fully exfoliated, they are single sheets 1 nanometer thick. These sheets thus have an aspect ratio of 1000 or more. They show promise as a component in composite materials. We report on AFM studies of the fully exfoliated sheets. AFM reveals impurities that are difficult to detect any other way. We will also report on methods to manipulate the sheets and to clean them of the impurities. We are laying the groundwork for extensive studies of the nanomechanics of these sheets, and of the interactions of individual clay layers with polymer chains.

  1. Launch Services, a Proven Model

    NASA Astrophysics Data System (ADS)

    Trafton, W. C.; Simpson, J.

    2002-01-01

    From a commercial perspective, the ability to justify "leap frog" technology such as reusable systems has been difficult to justify because the estimated 5B to 10B investment is not supported in the current flat commercial market coupled with an oversupply of launch service suppliers. The market simply does not justify investment of that magnitude. Currently, next generation Expendable Launch Systems, including Boeing's Delta IV, Lockheed Martin's Atlas 5, Ariane V ESCA and RSC's H-IIA are being introduced into operations signifying that only upgrades to proven systems are planned to meet the changes in anticipated satellite demand (larger satellites, more lifetime, larger volumes, etc.) in the foreseeable future. We do not see a new fleet of ELVs emerging beyond that which is currently being introduced, only continuous upgrades of the fleet to meet the demands. To induce a radical change in the provision of launch services, a Multinational Government investment must be made and justified by World requirements. The commercial market alone cannot justify such an investment. And if an investment is made, we cannot afford to repeat previous mistakes by relying on one system such as shuttle for commercial deployment without having any back-up capability. Other issues that need to be considered are national science and security requirements, which to a large extent fuels the Japanese, Chinese, Indian, Former Soviet Union, European and United States space transportation entries. Additionally, this system must support or replace current Space Transportation Economies with across-the-board benefits. For the next 10 to 20 years, Multinational cooperation will be in the form of piecing together launch components and infrastructure to supplement existing launch systems and reducing the amount of non-recurring investment while meeting the future requirements of the End-User. Virtually all of the current systems have some form of multinational participation: Sea Launch

  2. Performance of shortleaf pine provenances in Missouri

    Treesearch

    David Gwaze; Jennifer Myszewski; John Kabrick

    2007-01-01

    Two shortleaf pine (Pinus echinata Mill.) provenance tests established by the USDA Forest Service North Central Research Station as part of the South-wide Southern Pine Seed Source Study were examined to determine the most suitable seed sources for planting in Missouri. Each test comprised seven different provenances from six to seven states in the...

  3. Clay slurry and engineered soils as containment technologies for remediation of contaminated sites

    SciTech Connect

    Williams, J.R.; Dudka, S.; Miller, W.P.; Johnson, D.O.

    1997-12-31

    Clay Slurry and Engineered Soils are containment technologies for remediation of waste disposal sites where leaching, groundwater plumes and surface runoff of contaminants are serious ecological hazards to adjacent environments. This technology is a patent-pending process which involves the use of conditioned clay materials mixed with sand and water to form a readily pourable suspension, a clay slurry, which is either placed into a trench barrier system or allowed to de-water to create Engineered Soils. The Engineered Soil forms a layer impervious to water and air, therefore by inhibiting both water and oxygen from penetrating through the soil the material. This material can be installed in layers and as a vertical barrier to create a surface barrier containment system. The clay percentage in the clay slurry and Engineered Soils varies depending on site characteristics and desired performance standards. For example Engineered Soils with 1-2% of clay (dry wt.) had a hydraulic conductivity (K) of 10{sup -8} to 10{sup -1} cm/sec. Tests of tailing materials from a kyanite and pyrite mine showed that the clay slurry was effective not only in reducing the permeability of the treated tailings, but also in decreasing their acidity due to the inherent alkalinity of the clay. The untreated tailings had pH values in the range of 2.4 - 3.1; whereas, the effluent from clay and tailings mixtures had pH values in a slightly alkaline range (7.7-7.9). Pug-mills and high volume slurry pumps can be readily adapted for use in constructing and placing caps and creating Engineered Soils. Moreover, material on site or from a local sand supply can be used to create clay slurries and engineered soils. Clay materials used in cap construction are likewise readily available commercially. As a result, the clay slurry system is very cost effective compared to other capping systems, including the commonly used High Density Polyethylene (HDPE) liner systems.

  4. Clays and Clay Minerals and their environmental application in Food Technology

    NASA Astrophysics Data System (ADS)

    del Hoyo Martínez, Carmen; Cuéllar Antequera, Jorge; Sánchez Escribano, Vicente; Solange Lozano García, Marina; Cutillas Díez, Raul

    2013-04-01

    The clay materials have led to numerous applications in the field of public health (del Hoyo, 2007; Volzone, 2007) having been demonstrated its effectiveness as adsorbents of all contaminants. Some biodegradable materials are used for for adsorption of chemical contaminants: lignins (Valderrabano et al., 2008) and also clays and clay minerals, whose colloidal properties, ease of generating structural changes, abundance in nature, and low cost make them very suitable for this kind of applications. Among the strategies used at present to preserve the quality of the water and this way to diminish the environmental risk that supposes the chemical pollution, stands out the use of adsorbents of under cost, already they are natural or modified, to immobilize these compounds and to avoid the pollution of the water with the consequent reduction of environmental and economic costs Thanks to the development of the science and the technology of the nourishment in the last 50 years, there have revealed itself several new substances that can fulfill beneficial functions in the food, and these substances, named food additives, are today within reach of all. The food additives recover a very important role in the complex nourishing supply. The additives fulfill several useful functions in the food, which often we give for sat. Nevertheless the widespread use of food additives in the food production also influences the public health. The food industries, which are very important for the economy, spill residues proved from its activity that they have to be controlled to evaluate the environmental impact and to offer the necessary information about the quantitative evaluation of the chemical risk of the use of food additives for the public health. We have studied the adsorption of several contaminants by natural or modified clays, searching their interaction mechanisms and the possible recycling of these materials for environmental purposes and prevention of the health. References

  5. Preparation and thermal properties of Zr-intercalated clays

    SciTech Connect

    Figueras, F.; Mattrod-Bashi, A.; Fetter, G.; Thrierr, A. ); Zanchetta, J.V. )

    1989-09-01

    Montmorillonites intercalated by zirconium macrocations have been prepared. Diffusion of the Zr cations within the particles of clay controls the rate of ion exchange, and hence the distribution of the Zr pillars. This effect accounts for the influence of particle size on the degree of exchange, the surface area, and the thermal stability of the pillared clay. The thermal stability of the Zr clays prepared under these conditions is limited to 973 K in dry air. The changes in microporosity, evaluated from nitrogen adsorption using the equation of Dubinin, show that collapse of the structure occurs by sintering of the pillars. This sintering can be decreased by doping the pillars with rare earth cations. The resulting material then retains a surface area of 180 m{sup 2}/g after calcination at 1023 K in dry air, and is more acidic than the corresponding Zr-clay.

  6. Characterization of low-purity clays for geopolymer binder formulation

    NASA Astrophysics Data System (ADS)

    Mostafa, Nasser Y.; Mohsen, Q.; El-maghraby, A.

    2014-06-01

    The production of geopolymer binders from low-purity clays was investigated. Three low-purity clays were calcined at 750°C for 4 h. The calcined clays were chemically activated by the alkaline solutions of NaOH and Na2SiO3. The compressive strength was measured as a function of curing time at room temperature and 85°C. The results were compared with those of a pure kaolin sample. An amorphous aluminosilicate polymer was formed in all binders at both processing temperatures. The results show that, the mechanical properties depend on the type and amount of active aluminum silicates in the starting clay material, the impurities, and the processing temperature.

  7. Clay energetics in chemical evolution

    NASA Technical Reports Server (NTRS)

    Coyne, L. M.

    1986-01-01

    Clays have been implicated in the origin of terrestrial life since the 1950's. Originally they were considered agents which aid in selecting, concentrating and promoting oligomerization of the organic monomeric substituents of cellular life forms. However, more recently, it has been suggested that minerals, with particular emphasis on clays, may have played a yet more fundamental role. It has been suggested that clays are prototypic life forms in themselves and that they served as a template which directed the self-assembly of cellular life. If the clay-life theory is to have other than conceptual credibility, clays must be shown by experiment to execute the operations of cellular life, not only individually, but also in a sufficiently concerted manner as to produce some semblance of the functional attributes of living cells. Current studies are focussed on the ability of clays to absorb, store and transfer energy under plausible prebiotic conditions and to use this energy to drive chemistry of prebiotic relevance. Conclusions of the work are applicable to the role of clays either as substrates for organic chemistry, or in fueling their own life-mimetic processes.

  8. Active Provenance in Data-intensive Research

    NASA Astrophysics Data System (ADS)

    Spinuso, Alessandro; Mihajlovski, Andrej; Filgueira, Rosa; Atkinson, Malcolm

    2017-04-01

    Scientific communities are building platforms where the usage of data-intensive workflows is crucial to conduct their research campaigns. However managing and effectively support the understanding of the 'live' processes, fostering computational steering, sharing and re-use of data and methods, present several bottlenecks. These are often caused by the poor level of documentation on the methods and the data and how users interact with it. This work wants to explore how in such systems, flexibility in the management of the provenance and its adaptation to the different users and application contexts can lead to new opportunities for its exploitation, improving productivity. In particular, this work illustrates a conceptual and technical framework enabling tunable and actionable provenance in data-intensive workflow systems in support of reproducible science. It introduces the concept of Agile data-intensive systems to define the characteristic of our target platform. It shows a novel approach to the integration of provenance mechanisms, offering flexibility in the scale and in the precision of the provenance data collected, ensuring its relevance to the domain of the data-intensive task, fostering its rapid exploitation. The contributions address aspects of the scale of the provenance records, their usability and active role in the research life-cycle. We will discuss the use of dynamically generated provenance types as the approach for the integration of provenance mechanisms into a data-intensive workflow system. Enabling provenance can be transparent to the workflow user and developer, as well as fully controllable and customisable, depending from their expertise and the application's reproducibility, monitoring and validation requirements. The API that allows the realisation and adoption of a provenance type is presented, especially for what concerns the support of provenance profiling, contextualisation and precision. An actionable approach to provenance

  9. Clay and pillard clay membranes: Synthesis, characterization and transport properties

    NASA Astrophysics Data System (ADS)

    Vercauteren, Sven

    In this work, the preparation and characterization of ceramic multilayer membranes with an Alsb2Osb3-pillared montmorillonite (Al-PILC) and a Laponite separating layer have been studied. Al-PILC is a pillared clay prepared by intercalation of polyoxo cations of aluminium between the montmorillonite clay sheets, followed by a thermal treatment (400sp°C) to obtain rigid oxide pillars. The free spacing between the clay plates is about 0.8 nm. Laponite is a synthetic clay with a pore structure formed by the stacking of very small clay plates. To deposit an Al-PILC top layer on a macro- or mesoporous aluminiumoxide support membrane, two preparation routes were considered. According to the standard preparation route of a pillared clay, the easiest way is to use a suspension of clay mixed with the pillaring solution in which the support membrane is dipped. However, it is not possible to deposit uniform and crack-free top layers in this way because of the formation of unstable suspensions. A second preparation route is based on an indirect pillaring procedure. By dipping a support membrane in a stable clay suspension, a thin clay film is deposited in a first step. Pillaring is achieved via immersion of the supported clay film in the pillaring solution in a second step. After a washing procedure, the membrane is dried and calcined at 400sp°C. Laponite membranes were simply prepared by dipping a support membrane in a suspension of this synthetic clay in water. Afterwards a drying at room temperature and a calcination at 400 ar 500sp°C is performed. Both membrane types were tested for gas separation and pervaporation purposes. Transport of permanent gases (He, N2) occurs by means of Knudsen diffusion. Diffusion is kinetically controlled and for a binary mixture, the maximum separation factor is determined by the difference in molecular weight of both components. From pervaporation experiments with water/alcohol mixtures it was found that Al-PILC membranes can be used for

  10. Using the Complete Nano Engineering Geological Spectrum to Assess the Performance of Clay Barriers

    NASA Astrophysics Data System (ADS)

    Schmitz, Robrecht M.; Schroeder, Christian; Thorez, Jacques; Charlier, Robert

    Clays are geomaterials used in various (over 100) applications in our society. The more common geotechnical applications are clay barriers to contain waste, slurry walls etc. But even if clays are not used as construction material, the engineering geologist encounters them frequently during construction of e.g. foundations and tunnels. As clays are end products of the weathering of silicate geomaterials they are stable as such, but within this group of clay minerals, geotechnical properties vary enormously. Some of these variations are due to chemo-plasticity e.g. reflected in the effect of the composition of the pore fluid on the mechanical properties of clay. One approach to deal with these chemo plastic effects is to separate them according to the scale or level on which they are acting. In clays one can discern the level of the clay silicate sheets (TOT or TO), the clay interlayer level and the clay particles level. This contribution aims to show how an analysis of the processes on these three levels can help to assess the geotechnical properties of clays in contact with various fluids.

  11. Scanning electron microscopy of clays and clay minerals

    USGS Publications Warehouse

    Bohor, B.F.; Hughes, R.E.

    1971-01-01

    The scanning electron microscope (SEM) proves to be ideally suited for studying the configuration, texture, and fabric of clay samples. Growth mechanics of crystalline units-interpenetration and interlocking of crystallites, crystal habits, twinning, helical growth, and topotaxis-also are uniquely revealed by the SEM. Authigenic kaolins make up the bulk of the examples because their larger crystallite size, better crystallinity, and open texture make them more suited to examination by the SEM than most other clay mineral types. ?? 1971.

  12. In vitro toxicity evaluation of new silane-modified clays and the migration extract from a derived polymer-clay nanocomposite intended to food packaging applications.

    PubMed

    Maisanaba, Sara; Guzmán-Guillén, Remedios; Puerto, María; Gutiérrez-Praena, Daniel; Ortuño, Natalia; Jos, Ángeles

    2018-01-05

    The clay montmorillonite (Mt) is among the nanofillers more frequently used for food packaging applications. The organomodification of clays with different modifiers, such as silanes, is an important step in the preparation of improved polymer/clay materials known as nanocomposites. However, the toxicological data about these nanofillers is still scarce. In the present study, an in vitro toxicological evaluation in Caco-2 cells of two silane-modified clays based on Mt, Clay3 and Clay4 (0-250μg/ml), was performed. The cytotoxicity, cell death, genotoxicity and oxidative stress produced by both organoclays were evaluated after 24 and 48h of exposure. Moreover, the migration extracts obtained from nanocomposites of polypropylene (PP) + Clay3 and only PP were also investigated. Only Clay4 induced cytotoxicity, showing a reduction of cell viability to 63% of the control, as well as oxidative stress in a concentration-dependent manner. Regarding the PP-Clay3 migration extract, no cytotoxic effects were observed after exposure to the tested concentrations (0-100%). Moreover, significant differences in the presence of Ca, Mg and Si compared to the PP extract were obtained, although migration levels were in accordance with the food contact materials regulation. These findings indicate that a case-by-case toxicological assessment of organoclays should be performed. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Insightful understanding of the role of clay topology on the stability of biomimetic hybrid chitosan-clay thin films and CO2-dried porous aerogel microspheres.

    PubMed

    Frindy, Sana; Primo, Ana; Qaiss, Abou El Kacem; Bouhfid, Rachid; Lahcini, Mohamed; Garcia, Hermenegildo; Bousmina, Mosto; El Kadib, Abdelkrim

    2016-08-01

    Three natural clay-based microstructures, namely layered montmorillonite (MMT), nanotubular halloysite (HNT) and micro-fibrillar sepiolite (SP) were used for the synthesis of hybrid chitosan-clay thin films and porous aerogel microspheres. At a first glance, a decrease in the viscosity of the three gel-forming solutions was noticed as a result of breaking the mutual polymeric chains interaction by the clay microstructure. Upon casting, chitosan-clay films displayed enhanced hydrophilicity in the order CSclay microstructure, an improvement in the mechanical properties of the chitosan-clay films has been substantiated with CS-SP reaching the highest value at 5% clay loading. While clay addition provides a way to resist the shrinkage occurring for native chitosan, the enhanced hydrophilicity associated to the water content affects the efficacy of the CO2 super-critical drying as the most hydrophilic CS-SP microspheres face the highest shrinkage, resulting in a lowest specific surface area compared to CS-HNT and CS-MMT. Chitosan-clay exhibits enhanced thermal properties with the degradation delayed in the order CSclay compared to native chitosan, evidencing the beneficial protective effect of the clay particulates for the biopolymer. However, under hydrothermal treatment, the presence of clay was found to be detrimental to the material stability as a significant shrinkage occurs in hybrid CS-clay microspheres, which is attributed again to their increased hydrophilicity compared to the native polymeric microspheres. In this framework, a peculiar behavior was observed for CS-MMT, with the microspheres standing both against contraction during CO2 gel drying and under hydrothermal conditions. The knowledge gained from this rational design will constitute a guideline toward the preparation of ultra-stable, practically-optimized food

  14. Mechanisms of clay smear formation in 3D - a field study

    NASA Astrophysics Data System (ADS)

    Kettermann, Michael; Tronberens, Sebastian; Urai, Janos; Asmus, Sven

    2016-04-01

    Clay smears in sedimentary basins are important factors defining the sealing properties of faults. However, as clay smears are highly complex 3D structures, processes involved in the formation and deformation of clay smears are not well identified and understood. To enhance the prediction of sealing properties of clay smears extensive studies of these structures are necessary including the 3D information. We present extraordinary outcrop data from an open cast lignite mine (Hambach) in the Lower Rhine Embayment, Germany. The faults formed at a depth of 150 m, and have Shale Gouge Ratios between 0.1 and 0.3. Material in the fault zones is layered, with sheared sand, sheared clay and tectonically mixed sand-clay gouge. We studied the 3D thickness distribution of clay smear from a series of thin-spaced incremental cross-sections and several cross-sections in larger distances along the fault. Additionally, we excavated two large clay smear surfaces. Our observations show that clay smears are strongly affected by R- and R'-shears, mostly at the footwall side of our outcrops. These shears can locally cross and offset clay smears, forming holes. Thinnest parts of the clay smears are often located close to source layer cutoffs. Investigating the 3D thickness of the clay smears shows a heterogeneous distribution, rather than a continuous thinning of the smear with increasing distance to the source layers. We found two types of layered clay smears: one with continuous sheared sand between two clay smears providing vertical pathways for fluid flow, and one which consists of overlapping clay patches separated by sheared sand that provide a tortuous pathway across the clay smear. On smaller scale we identified grain-scale mixing as an important process for the formation of clay smears. Sand can be entrained into the clay smear by mixing from the surrounding host rock as well as due to intense shearing of sand lenses that were incorporated into the smear. This causes clay smears

  15. Clay exfoliation and polymer/clay aerogels by supercritical carbon dioxide

    PubMed Central

    Longo, Simona; Mauro, Marco; Daniel, Christophe; Galimberti, Maurizio; Guerra, Gaetano

    2013-01-01

    Supercritical carbon dioxide (scCO2) treatments of a montmorillonite (MMT) intercalated with ammonium cations bearing two long hydrocarbon tails (organo-modified MMT, OMMT) led to OMMT exfoliation, with loss of the long-range order in the packing of the hydrocarbon tails and maintenance of the long-range order in the clay layers. The intercalated and the derived exfoliated OMMT have been deeply characterized, mainly by X-ray diffraction analyses. Monolithic composite aerogels, with large amounts of both intercalated and exfoliated OMMT and including the nanoporous-crystalline δ form of syndiotactic polystyrene (s-PS), have been prepared, by scCO2 extractions of s-PS-based gels. Also for high OMMT content, the gel and aerogel preparation procedures occur without re-aggregation of the exfoliated clay, which is instead observed for other kinds of polymer processing. Aerogels with the exfoliated OMMT have more even dispersion of the clay layers, higher elastic modulus and larger surface area than aerogels with the intercalated OMMT. Extremely light materials with relevant transport properties could be prepared. Moreover, s-PS-based aerogels with exfoliated OMMT could be helpful for the handling of exfoliated clay minerals. PMID:24790956

  16. Provenance Storage, Querying, and Visualization in PBase

    SciTech Connect

    Kianmajd, Parisa; Ludascher, Bertram; Missier, Paolo; Chirigati, Fernando; Wei, Yaxing; Koop, David; Dey, Saumen

    2015-01-01

    We present PBase, a repository for scientific workflows and their corresponding provenance information that facilitates the sharing of experiments among the scientific community. PBase is interoperable since it uses ProvONE, a standard provenance model for scientific workflows. Workflows and traces are stored in RDF, and with the support of SPARQL and the tree cover encoding, the repository provides a scalable infrastructure for querying the provenance data. Furthermore, through its user interface, it is possible to: visualize workflows and execution traces; visualize reachability relations within these traces; issue SPARQL queries; and visualize query results.

  17. Adsorption of bacteriophages on clay minerals

    USGS Publications Warehouse

    Chattopadhyay, Sandip; Puls, Robert W.

    1999-01-01

    The ability to predict the fate of microorganisms in soil is dependent on an understanding of the process of their sorption on soil and subsurface materials. Presently, we have focused on studying the thermodynamics of sorption of bacteriophages (T-2, MS-2, and φX-174) on clays (hectorite, saponite, kaolinite, and clay fraction of samples collected from a landfill site). The thermodynamic study not only determines the feasibility of the process but also provides information on the relative magnitudes of the different forces under a particular set of conditions. The total free energy of interaction during sorption of bacteriophages on clays (ΔG) has been assumed to be the summation of ΔGH (ΔG due to hydrophobic interactions) and ΔGEL (ΔG due to electrostatic interactions). The magnitude of ΔGH was determined from the different interfacial tensions (γ) present in the system, while ΔGEL was calculated from ζ-potentials of the colloidal particles. Calculated results show that surface hydrophobicities of the selected sorbents and sorbates dictate sorption. Among the selected bacteriophages, maximum sorption was observed with T-2, while hectorite has the maximum sorption capacity. Experimental results obtained from the batch adsorption studies also corroborated those obtained from the theoretical study.

  18. Tool for Taking Clay Impressions

    NASA Technical Reports Server (NTRS)

    Duncan, R. S.

    1984-01-01

    Clay impression of small parts taken with tool consisting of hollow tube closed at one end. Slots at other end admit part short distance into tube. Impression used to make silicone rubber mold for examination.

  19. Tool for Taking Clay Impressions

    NASA Technical Reports Server (NTRS)

    Duncan, R. S.

    1984-01-01

    Clay impression of small parts taken with tool consisting of hollow tube closed at one end. Slots at other end admit part short distance into tube. Impression used to make silicone rubber mold for examination.

  20. Clay mineralogy in agrochernozems of western Ukraine

    NASA Astrophysics Data System (ADS)

    Papish, I. Ya.; Chizhikova, N. P.; Poznyak, S. P.; Varlamov, E. B.

    2016-10-01

    The mineralogy of clay fractions separated from deep low-humus deep-gleyic loamy typical agrochernozems on loess-like loams of the Upper Bug and Dniester uplands in the Central Russian loess province of Ukraine consists of complex disordered interstratifications with the segregation of mica- and smectite-type layers (hereafter, smectite phase), tri- and dioctahedral hydromicas, kaolinite, and chlorite. The distribution of the clay fraction is uniform. The proportions of the layered silicates vary significantly within the profile: a decrease in the content of the smectite phase and a relative increase in the content of hydromicas up the soil profile are recorded. In the upper horizons, the contents of kaolinite and chlorite increase, and some amounts of fine quartz, potassium feldspars, and plagioclases are observed. This tendency is observed in agrochernozems developed on the both Upper Bug and Dniester uplands. The differences include the larger amounts of quartz, potassium feldspars, and plagioclases in the clay material of the Upper Bug Upland, while the contents of the smectite phase in the soil profiles of the areas considered are similar. An analogous mineral association is noted in podzolized agrochernozems on loess-like deposits in the Cis-Carpathian region of the Southern Russian loess province developed on the Prut-Dniester and Syan-Dniester uplands. The distribution of particle-size fractions and the mineralogy of the clay fraction indicate the lithogenic heterogeneity of the soil-forming substrate. When the drifts change, the mineral association of the soils developed within the loess-like deposits gives place to minerals dominated by individual smectite with some mica-smectite inter stratifications, hydromicas, and chlorite.

  1. Nigerian geophagical clay: a traditional antidiarrheal pharmaceutical.

    PubMed

    Vermeer, D E; Ferrell, R E

    1985-02-08

    The chief geophagical clay entering the West African market system comes from the village of Uzalla, Nigeria. Village inhabitants ascribe antidiarrheal properties to the clay, and they use it in traditional medicinal preparations to counteract intestinal problems. Mineralogical analyses demonstrate a striking similarity between the Uzalla village clay and the clay in the commercial pharmaceutical Kaopectate.

  2. From static to dynamic provenance analysis-Sedimentary petrology upgraded

    NASA Astrophysics Data System (ADS)

    Garzanti, Eduardo

    2016-05-01

    The classical approach to sandstone petrology, established in the golden years of plate tectonics and based on the axiom that "detrital modes of sandstone suites primarily reflect the different tectonic settings of provenance terranes," has represented a benchmark for decades. The composition of sand and sandstone, however, simply provides us with a distorted image of the lithological structure of source terranes and gives us little clue whether they are allochthonous or autochthonous, orogenic or anorogenic, young or old. What we may able to see reflected in detrital modes is the nature of source terranes (continental, arc, oceanic) and the tectonostratigraphic level reached by erosion in space and time. The proposed new approach to the petrology of sand and sandstone (1) starts with a simple classification scheme circulated since the 1960s, which is purely descriptive, objective, and free of ill-defined ambiguous terms and (2) focuses on the nature and tectonostratigraphic level of source terranes. Further steps are essential to upgrade provenance analysis. Acquiring knowledge from modern settings is needed to properly identify and wherever possible correct for physical and chemical processes introducing environmental and diagenetic bias and thus address nature's complexities with adequate conceptual tools. Equally important is the integration of multiple techniques, ideally including bulk-sediment, multi-mineral, and single-mineral methods. Bulk-sediment petrography remains the fundamental approach that allows us to capture the most precious source of direct provenance information, represented by the mineralogy and texture of rock fragments. Bulk-sediment geochemistry, applicable also to silt and clay carried in suspension, is a superior method to check for hydraulic sorting, chemical weathering, and fertility of detrital minerals in different sediment sources. Detrital geochronology, thermochronology, and isotope geochemistry reveal the diverse time structures

  3. Coupled Heat and Moisture Transport Simulation on the Re-saturation of Engineered Clay Barrier

    NASA Astrophysics Data System (ADS)

    Huang, W. H.; Chuang, Y. F.

    2014-12-01

    Engineered clay barrier plays a major role for the isolation of radioactive wastes in a underground repository. This paper investigates the resaturation processes of clay barrier, with emphasis on the coupling effects of heat and moisture during the intrusion of groundwater to the repository. A reference bentonite and a locally available clay were adopted in the laboratory program. Soil suction of clay specimens was measured by psychrometers embedded in clay specimens and by vapor equilibrium technique conducted at varying temperatures so as to determine the soil water characteristic curves of the two clays at different temperatures. And water uptake tests were conducted on clay specimens compacted at various densities to simulate the intrusion of groundwater into the clay barrier. Using the soil water characteristic curve, an integration scheme was introduced to estimate the hydraulic conductivity of unsaturated clay. It was found that soil suction decreases as temperature increases, resulting in a reduction in water retention capability. The finite element method was then employed to carry out the numerical simulation of the saturation process in the near field of a repository. Results of the numerical simulation were validated using the degree of saturation profile obtained from the water uptake tests on the clays. The numerical scheme was then extended to establish a model simulating the resaturation process after the closure of a repository. Finally, the model was then used to evaluate the effect of clay barrier thickness on the time required for groundwater to penetrate the clay barrier and approach saturation. Due to the variation in clay suction and thermal conductivity with temperature of clay barrier material, the calculated temperature field shows a reduction as a result of incorporating the hydro-properties in the calculations.

  4. Simultaneous enhancements of UV resistance and mechanical properties of polypropylene by incorporation of dopamine-modified clay.

    PubMed

    Phua, Si Lei; Yang, Liping; Toh, Cher Ling; Guoqiang, Ding; Lau, Soo Khim; Dasari, Aravind; Lu, Xuehong

    2013-02-01

    Inspired by the radical scavenging function of melanin-like materials and versatile adhesive ability of mussel-adhesion proteins, dopamine-modified clay (D-clay) was successfully incorporated into polypropylene (PP) using an amine-terminated PP oligomer as the compatibilizer. Although the PP/D-clay nanocomposites exhibit intercalated morphology, the incorporation of D-clay greatly improves the thermo-oxidative stability and UV resistance of PP owing to the strong radical scavenging ability of polydopamine (PDA) and large contact area between PP and the PDA coating on clay mineral. Moreover, the reinforcement effect brought by D-clay is fairly significant at very low clay loadings probably owing to the strong interfacial interactions between the layered silicates and the compatibilizer as well as that between the compatibilizer and the PP matrix. The work demonstrates that D-clay is a type of promising nanofiller for thermoplastics used for outdoor applications since it stabilizes and reinforces the polymers simultaneously.

  5. Studies of clays and clay minerals using x-ray powder diffraction and the Rietveld method

    SciTech Connect

    Bish, D.L.

    1993-09-01

    The Rietveld method was originally developed (Rietveld, 1967, 1969) to refine crystal structures using neutron powder diffraction data. Since then, the method has been increasingly used with X-ray powder diffraction data, and today it is safe to say that this is the most common application of the method. The method has been applied to numerous natural and synthetic materials, most of which do not usually form crystals large enough for study with single-crystal techniques. It is the ability to study the structures of materials for which sufficiently large single crystals do not exist that makes the method so powerful and popular. It would thus appear that the method is ideal for studying clays and clay minerals. In many cases this is true, but the assumptions implicit in the method and the disordered nature of many clay minerals can limit titsapplicability. This chapter will describe the Rietveld method, emphasizing the assumptions important for the study of disordered materials, and it will outline the potential applications of the method to these minerals. These applications include, in addition to the refinement of crystal structures, quantitative analysis of multicomponent mixtures, analysis of peak broadening, partial structure solution, and refinement of unit-cell parameters.

  6. Degradation of Nylon-6/Clay Nanocomposites in NO(x)

    NASA Astrophysics Data System (ADS)

    Shelley, J. S.; Devries, K. L.

    2000-04-01

    Nylon-6 is an important engineering polymer that, in its fully spherulitic (bulk) form, has many applications in gears, rollers, and other long life cycle components. In 1993, Toyota commercialized a nylon-6/clay nanocomposite out of which it produced the timing belt cover for the 1993 Camry. Although these hybrid nanocomposites show significant improvements in their mechanical response characteristics, including yield strength and heat distortion temperature, little is known about the degradation of these properties due to environmental pollutants like NOx. Nylon-6 fibers are severely degraded by interaction with NOx and other pollutants, showing a strong synergism between applied load and environmental degradation. While the nanocomposites show a significant reduction in permeability of gases and water due to the incorporation of lamellar clay, their susceptibility to non-diffusional mechano-chemical degradation is unknown. The fracture toughness of these nylon-6/day nanocomposites increases, not as a function of clay content, but as a function of the volume of nylon-6 polymer chains influenced by the clay lamellar surfaces. Both the clay and the constrained volume offer the nanocomposites some protection from the deleterious effects of NOx. The time-to-failure at a given stress intensity factor as a function of clay content and constrained volume will be discussed along with fracture toughness of the materials.

  7. New polyelectrolyte complex from pectin/chitosan and montmorillonite clay.

    PubMed

    da Costa, Marcia Parente Melo; de Mello Ferreira, Ivana Lourenço; de Macedo Cruz, Mauricio Tavares

    2016-08-01

    A new nanocomposite hydrogel was prepared by forming a crosslinked hybrid polymer network based on chitosan and pectin in the presence of montmorillonite clay. The influence of clay concentration (0.5 and 2% wt) as well as polymer ratios (1:1, 1:2 and 2:1) was investigated carefully. The samples were characterized by different techniques: transmission and scanning electron microscopy, X-ray diffraction, thermogravimetric analysis, infrared spectroscopy, swelling degree and compression test. Most samples presented swelling degree above 1000%, which permits characterizing them as superabsorbent material. Images obtained by transmission electron microscopy showed the presence of clay nanoparticles into hydrogel. The hydrogels' morphological properties were evaluated by scanning electron microscope in high and low-vacuum. The micrographs showed that the samples presented porous. The incorporation of clay produced hydrogels with differentiated morphology. Thermogravimetric analysis results revealed that the incorporation of clay in the samples provided greater thermal stability to the hydrogels. The compression resistance also increased with addition of clay.

  8. Kisameet Glacial Clay: an Unexpected Source of Bacterial Diversity

    PubMed Central

    Svensson, Sarah L.; Behroozian, Shekooh; Xu, Wanjing; Surette, Michael G.; Li, Loretta

    2017-01-01

    ABSTRACT Widespread antibiotic resistance among bacterial pathogens is providing the impetus to explore novel sources of antimicrobial agents. Recently, the potent antibacterial activity of certain clay minerals has stimulated scientific interest in these materials. One such example is Kisameet glacial clay (KC), an antibacterial clay from a deposit on the central coast of British Columbia, Canada. However, our understanding of the active principles of these complex natural substances is incomplete. Like soils, clays may possess complex mixtures of bacterial taxa, including the Actinobacteria, a clade known to be rich in antibiotic-producing organisms. Here, we present the first characterization of both the microbial and geochemical characteristics of a glacial clay deposit. KC harbors surprising bacterial species richness, with at least three distinct community types. We show that the deposit has clines of inorganic elements that can be leached by pH, which may be drivers of community structure. We also note the prevalence of Gallionellaceae in samples recovered near the surface, as well as taxa that include medically or economically important bacteria such as Actinomycetes and Paenibacillus. These results provide insight into the microbial taxa that may be the source of KC antibacterial activity and suggest that natural clays may be rich sources of microbial and molecular diversity. PMID:28536287

  9. Acid activation of bentonites and polymer-clay nanocomposites.

    SciTech Connect

    Carrado, K. A.; Komadel, P.; Center for Nanoscale Materials; Slovak Academy of Sciences

    2009-04-01

    Modified bentonites are of widespread technological importance. Common modifications include acid activation and organic treatment. Acid activation has been used for decades to prepare bleaching earths for adsorbing impurities from edible and industrial oils. Organic treatment has sparked an explosive interest in a class of materials called polymer-clay nanocomposites (PCNs). The most commonly used clay mineral in PCNs is montmorillonite, which is the main constituent of bentonite. PCN materials are used for structural reinforcement and mechanical strength, for gas permeability barriers, as flame retardants, and to minimize surface erosion (ablation). Other specialty applications include use as conducting nanocomposites and bionanocomposites.

  10. Tracking Provenance of Earth Science Data

    NASA Technical Reports Server (NTRS)

    Tilmes, Curt; Yesha, Yelena; Halem, Milton

    2010-01-01

    Tremendous volumes of data have been captured, archived and analyzed. Sensors, algorithms and processing systems for transforming and analyzing the data are evolving over time. Web Portals and Services can create transient data sets on-demand. Data are transferred from organization to organization with additional transformations at every stage. Provenance in this context refers to the source of data and a record of the process that led to its current state. It encompasses the documentation of a variety of artifacts related to particular data. Provenance is important for understanding and using scientific datasets, and critical for independent confirmation of scientific results. Managing provenance throughout scientific data processing has gained interest lately and there are a variety of approaches. Large scale scientific datasets consisting of thousands to millions of individual data files and processes offer particular challenges. This paper uses the analogy of art history provenance to explore some of the concerns of applying provenance tracking to earth science data. It also illustrates some of the provenance issues with examples drawn from the Ozone Monitoring Instrument (OMI) Data Processing System (OMIDAPS) run at NASA's Goddard Space Flight Center by the first author.

  11. Tracking Provenance of Earth Science Data

    NASA Technical Reports Server (NTRS)

    Tilmes, Curt; Yesha, Yelena; Halem, Milton

    2010-01-01

    Tremendous volumes of data have been captured, archived and analyzed. Sensors, algorithms and processing systems for transforming and analyzing the data are evolving over time. Web Portals and Services can create transient data sets on-demand. Data are transferred from organization to organization with additional transformations at every stage. Provenance in this context refers to the source of data and a record of the process that led to its current state. It encompasses the documentation of a variety of artifacts related to particular data. Provenance is important for understanding and using scientific datasets, and critical for independent confirmation of scientific results. Managing provenance throughout scientific data processing has gained interest lately and there are a variety of approaches. Large scale scientific datasets consisting of thousands to millions of individual data files and processes offer particular challenges. This paper uses the analogy of art history provenance to explore some of the concerns of applying provenance tracking to earth science data. It also illustrates some of the provenance issues with examples drawn from the Ozone Monitoring Instrument (OMI) Data Processing System (OMIDAPS) run at NASA's Goddard Space Flight Center by the first author.

  12. Determination of geomagnetic archaeomagnitudes from clay pipes

    NASA Astrophysics Data System (ADS)

    Games, K. P.; Baker, M. E.

    1981-02-01

    Archaeomagnitude determinations of a selection of clay pipes dateable to AD 1645+/-10 as well as studies of pottery samples from the same site and of the same age have been made. Values of the magnitude of the ancient magnetic field (Banc), were obtained from two pottery sherds, two pipe bowls and three pipe stems. The values from the sherds and bowls agree within 2% and compare well with the average value of the magnitude of the magnetic field for the seventeenth century as determined by other archaeomagnetic studies. However, the pipe stems give values of Banc which are significantly less than those from the bowls and pottery. We have not yet been able to explain this and thus we suggest that reliable archaeomagnitude determinations can be made from the bowls of clay pipes but not from the stems. Nevertheless, this result provides a new source of material for investigating variations in the geomagnetic field strength over the past 400 yr. Clay pipes have been manufactured in England since the end of the sixteenth century. In the firing process some pipes were broken and disposed of without ever having been smoked. One such collection, discovered at Rainford, Lancashire, in 1978, consisted of a series of discrete dumps including pipes, kiln debris and a small collection of contemporary used earthenware sherds. The internal consideration of the dumps suggested a very short period of activity and archaeologists (P. Davey, personal communication) ascribe all the material to the period 1645+/-10 yr. With such well-dated material, we set out to check whether or not reliable archaeomagnitudes could be obtained from the pipes.

  13. Cenozoic sedimentation rates and provenance variations in the South Pacific Gyre

    NASA Astrophysics Data System (ADS)

    Dunlea, A. G.; Murray, R. W.; Sauvage, J.; Spivack, A. J.; Harris, R. N.; D'Hondt, S. L.

    2013-12-01

    Pelagic clays are traditionally difficult to date due to the scarcity of biogenic deposition and the prevalence of homogenous, altered, very fine-grain sediment. Integrated Ocean Drilling Program Expedition 329 recovered completely oxic, brown, pelagic zeolitic metalliferous clay from the South Pacific Gyre (SPG). Despite post-depositional alteration, the sediment retains enough of its original chemical signature to track downcore changes in provenance. Of particular interest is the cosmogenic portion of the sediment (e.g., Co), which we use to determine sedimentation rates and explore the paleoceanographic implications of changing sedimentation in the SPG throughout the Cenozoic. Under the assumption that the flux of extraterrestrial cosmogenic dust is spatially and temporally constant (or can at least be constrained), the concentration of cosmic dust in the sediment is inversely proportional to the sedimentation rate. Previous studies have used this premise to successfully date pelagic clays and Fe-Mn crusts, using Co as a proxy for cosmic dust deposition. The SPG has the slowest marine sedimentation rates in the world (as low as 0.1 m/Myr) and subsequently has the highest concentration of cosmic dust in the seafloor, making it an ideal region to apply this techniques. Building upon Zhou and Kyte (1992, Paleocean., 7, 441-465) at the single location of DSDP Site 596, we are dating SPG pelagic clays and identifying provenance variations throughout the SPG using a combined analytical and statistical approach. We analyze bulk sediment from Exp. 329 for a wide suite of major, trace, and rare earth elements by ICP-ES/MS. We apply multivariate statistical methods to quantify the contributions through time from various sources, aiming to distinguish a cosmogenic component. From the cosmogenic abundances, we produce a high-resolution record of instantaneous sedimentation rates of SPG pelagic clays during the Cenozoic. Our preliminary constant cosmogenic Co models show

  14. Hydrolysis of carbaryl by carbonate impurities in reference clay SWy-2.

    PubMed

    Arroyo, L Jacqueline; Li, Hui; Teppen, Brian J; Johnston, Cliff T; Boyd, Stephen A

    2004-12-29

    The influence of clay preparation methods on the sorption and hydrolysis of carbaryl (1-naphthyl, N-methyl carbamate) by K+-saturated reference smectite SWy-2 was studied. Four methods were utilized: (1) The reference (or specimen) clay used as received was K+-saturated (hereafter referred to as whole clay). (2) High-speed centrifugation (3295g) of whole clay resulted in a pellet with three discrete bands. The upper, light-colored, low-density band was obtained by manual separation (light fraction). The high-density, dark-colored material comprising the lower band (heavy fraction) was also obtained manually. (3) SWy-2 was subjected to overnight gravity sedimentation to obtain the <2 microm particles (clay-sed.) and then K+-saturated. (4) SWy-2 was subjected to low-speed centrifugation (58-60g) to separate the <2 microm particle size (clay-cent.) and then K+-saturated. Each preparation of mineral fractions manifested significantly different abilities to hydrolyze carbaryl to 1-naphthol, decreasing in the order whole clay > heavy fraction > clay-sed. > light clay > clay-cent. The extent of 1-naphthol disappearance from solution, accompanied by a progressive darkening of the clay, followed the order whole clay > heavy fraction > light clay > clay-sed. > clay-cent. Using ring labeled [14C]carbaryl, approximately 61 and 15% of the total 14C activity added to the whole clay and light fraction, respectively, remained unextractable. X-ray diffraction of the heavy fraction revealed several peaks corresponding to minor impurities, including calcite and dolomite. Aqueous slurries of whole clay, light fraction, clay-sed., and heavy fraction were alkaline, whereas the pH of slurried clay-cent. was neutral. It was concluded that dissolution of inorganic carbonate impurities in SWy-2 caused alkaline conditions in the slurries leading to the hydrolysis of carbaryl. Dissolution of carbonates with sodium acetate buffer eliminated hydrolytic activity associated with SWy-2. None of

  15. Clay mineral evolution in the central Yellow Sea mud deposits

    NASA Astrophysics Data System (ADS)

    Cho, H. G.; Kim, D. C.; Yi, H.-I.

    2012-04-01

    The Yellow Sea, a typical epicontinental shelf located between China and Korea, has attracted by many researchers for the study of late Quaternary land-ocean interaction and paleoenvironmental changes. There are four main mudbelt deposits such as North Yellow Sea Mud (NWMD), Central Yellow Sea Mud (CYSM), Southeastern Yellow Sea Mud (SWYSM), and Southwestern Cheju Island Mud (SWCIM). These mudbelt deposits are mostly composed of fine-grained sediments with detrital origin, which mainly come from several rivers in China and Korea. In this study we reconstruct the evolution of clay mineral assemblages in Core YS11-PCL14 (35o 47.07'N, 124 o 06.89' E) retrieved from the Central Yellow Sea Mud. Clay mineral compositions of 67 samples taken at ~10 cm intervals from YS11-PLC14 core sediments and 31 river sediments flowed into the Yellow Sea were determined using the semi-quantitative X-ray diffraction analysis. The clay-mineral assemblage of core sediments are composed of illite (60~75%), chlorite (11~23%), kaolinite (10~15%), and smectite (1~7%), in decreasing order. The ratio (smectite/illite)*100 is abruptly decreases at depth around 200 cm, and is corresponded to abrupt increase in clay fraction. The lower part of core sediments having higher (smectite/illite)*100 ratio are derived ultimately from the Huanghe, because Huanghe only discharges sediments containing the higher (smectite/illite)*100 ratio among the rivers flowed into the Yellow Sea. According to age-dating in the adjacent Core 06-2 (35o 00'N, 124 o 25' E), the depth at abrupt change in clay fraction corresponds to about 5,000 yr. Clay mineral evolution in Central Yellow Sea Mud is closely related to changes in sediment provenance and paleoenvironment. Sea level rise and the strength of the Kuroshio Current control the dispersal and deposition of clays on the Yellow Sea shelf, and thus, determine the clay mineral compositions in the core sediments. Before 5,000 yr, sediments discharged from Huanghe have a

  16. Impact of clay minerals on sulfate-reducing activity in aquifers

    USGS Publications Warehouse

    Wong, D.; Suflita, J.M.; McKinley, J.P.; Krumholz, L.R.

    2004-01-01

    Previous studies have shown that sulfate-reduction activity occurs in a heterogeneous manner throughout the terrestrial subsurface. Low-activity regions are often observed in the presence of clay minerals. Here we report that clays inhibit sulfate reduction activity in sediments and in a pure culture of Desulfovibriovulgaris. Clay minerals including bentonite and kaolinite inhibited sulfate reduction by 70–90% in sediments. Intact clays and clay colloids or soluble components, capable of passing through a 0.2-µm filter, were also inhibitory to sulfate-reducing bacteria. Other adsorbent materials, including anion or cation exchangers and a zeolite, did not inhibit sulfate reduction in sediments, suggesting that the effect of clays was not due to their cation-exchange capacity. We observed a strong correlation between the Al2O3content of clays and their relative ability to inhibit sulfate reduction in sediments (r2 = 0.82). This suggested that inhibition might be a direct effect of Al3+ (aq) on the bacteria. We then tested pure aluminum oxide (Al2O3) and showed it to act in a similar manner to clay. As dissolved aluminum is known to be toxic to a variety of organisms at low concentrations, our results suggest that the effects of clay on sulfate-reducing bacteria may be directly due to aluminum. Thus, our experiments provide an explanation for the lack of sulfate-reduction activity in clay-rich regions and presents a mechanism for the effect.

  17. Effect of red clay on diesel bioremediation and soil bacterial community.

    PubMed

    Jung, Jaejoon; Choi, Sungjong; Hong, Hyerim; Sung, Jung-Suk; Park, Woojun

    2014-08-01

    Red clay is a type of soil, the red color of which results from the presence of iron oxide. It is considered an eco-friendly material, with many industrial, cosmetic, and architectural uses. A patented method was applied to red clay in order to change its chemical composition and mineral bioavailability. The resulting product was designated processed red clay. This study evaluates the novel use of red clay and processed red clay as biostimulation agents in diesel-contaminated soils. Diesel biodegradation was enhanced in the presence of red clay and processed red clay by 4.9- and 6.7-fold, respectively, and the number of culturable bacterial cells was correlated with the amount of diesel biodegradation. The growth of Acinetobacter oleivorans DR1, Pseudomonas putida KT2440, and Cupriavidus necator was promoted by both types of red clays. Culture-independent community analysis determined via barcoded pyrosequencing indicated that Nocardioidaceae, Xanthomonadaceae, Pseudomonadaceae, and Caulobacteraceae were enriched by diesel contamination. Bacterial strain isolation from naphthalene- and liquid paraffin-amended media was affiliated with enriched taxa based on 16S rRNA gene sequence identity. We suggest that the biostimulating mechanism of red clay and processed red clay is able to support bacterial growth without apparent selection for specific bacterial species.

  18. Modeling Coupled Processes in Clay Formations for Radioactive Waste Disposal

    SciTech Connect

    Liu, Hui-Hai; Rutqvist, Jonny; Zheng, Liange; Sonnenthal, Eric; Houseworth, Jim; Birkholzer, Jens

    2010-08-31

    As a result of the termination of the Yucca Mountain Project, the United States Department of Energy (DOE) has started to explore various alternative avenues for the disposition of used nuclear fuel and nuclear waste. The overall scope of the investigation includes temporary storage, transportation issues, permanent disposal, various nuclear fuel types, processing alternatives, and resulting waste streams. Although geologic disposal is not the only alternative, it is still the leading candidate for permanent disposal. The realm of geologic disposal also offers a range of geologic environments that may be considered, among those clay shale formations. Figure 1-1 presents the distribution of clay/shale formations within the USA. Clay rock/shale has been considered as potential host rock for geological disposal of high-level nuclear waste throughout the world, because of its low permeability, low diffusion coefficient, high retention capacity for radionuclides, and capability to self-seal fractures induced by tunnel excavation. For example, Callovo-Oxfordian argillites at the Bure site, France (Fouche et al., 2004), Toarcian argillites at the Tournemire site, France (Patriarche et al., 2004), Opalinus clay at the Mont Terri site, Switzerland (Meier et al., 2000), and Boom clay at Mol site, Belgium (Barnichon et al., 2005) have all been under intensive scientific investigations (at both field and laboratory scales) for understanding a variety of rock properties and their relations with flow and transport processes associated with geological disposal of nuclear waste. Clay/shale formations may be generally classified as indurated and plastic clays (Tsang et al., 2005). The latter (including Boom clay) is a softer material without high cohesion; its deformation is dominantly plastic. For both clay rocks, coupled thermal, hydrological, mechanical and chemical (THMC) processes are expected to have a significant impact on the long-term safety of a clay repository. For

  19. In situ interaction between different concretes and Opalinus Clay

    NASA Astrophysics Data System (ADS)

    Jenni, A.; Mäder, U.; Lerouge, C.; Gaboreau, S.; Schwyn, B.

    Interactions between cementitious materials and claystone are driven by chemical gradients in pore water and might lead to mineralogical modifications in both materials. In the context of a radioactive waste repository, this alteration might influence safety-relevant clay properties like swelling pressure, permeability, or specific retention. In this study, interfaces of Opalinus Clay, a potential host-rock in Switzerland, and three concrete formulations emplaced in the Cement-Clay Interaction (CI) Experiment at the Mont Terri Underground Laboratory (St. Ursanne, Switzerland) were analysed after 2.2 years of interaction. Sampling techniques with interface stabilisation followed by inclined intersection drilling were developed. Element distribution maps of the concrete-clay interfaces show complex zonations like sulphur enrichment, zones depleted in Ca but enriched in Mg, strong Mg enrichment adjacent to the interface, or carbonation. Consistently, the carbonated zone shows a reduced porosity. Properties of the complex zonation strongly depend on cement properties like water content and pH (ordinary Portland cement vs. low-pH cement). An increased Ca or Mg content in the first 100 μm next to the interface is observed in Opalinus Clay. The cation occupancy of clay exchanger phases next to the ordinary Portland cement interface is depleted in Mg, but enriched in Na, whereas porosity shows no changes at all. The current data suggests migration of CO2/HCO3-, SO42-, and Mg species from clay into cement. pH decrease in the cement next to the interface leads to instability of ettringite, and the sulphate liberated diffuses towards higher pH regions (away from the interface), where additional ettringite can form.

  20. Falling for Clay Leaves.

    ERIC Educational Resources Information Center

    Kernan, Christine

    2002-01-01

    Describes an art project that integrated science and art education. Explains that students create ceramic bowls by using real leaves. Discusses the process of creating the ceramic bowls, including how to glaze the bowls. Includes a list of materials. (CMK)

  1. Falling for Clay Leaves.

    ERIC Educational Resources Information Center

    Kernan, Christine

    2002-01-01

    Describes an art project that integrated science and art education. Explains that students create ceramic bowls by using real leaves. Discusses the process of creating the ceramic bowls, including how to glaze the bowls. Includes a list of materials. (CMK)

  2. Clay minerals as proxies of the late Quaternary East Asian monsoon evolution in the South China Sea revisited

    NASA Astrophysics Data System (ADS)

    Liu, Z.; Li, X.; He, Z.; Colin, C.; Zhao, Y.

    2012-12-01

    Clay minerals have a significant role in sedimentation and paleoenvironment studies of the South China Sea. Many previous studies showed that the time series variation in late Quaternary clay mineral assemblages presents mostly glacial-interglacial cyclicity, and they were interpreted chemical weathering closely related to contemporaneous climatic changes of source areas. It is quite debatable whether clay minerals can directly indicate the East Asian monsoon evolution. To answer this question, we investigated sediment cores collected in various locations in the South China Sea during the MARCO POLO cruise in 2005, MD05-2904 (2066 m water depth, abbreviated w.d.) and MD05-2905 (1198 m w.d.) in the north, MD05-2901 (1254 m w.d.) and MD05-2899 (2393 m w.d.) in the west, and MD05-2895 (1982 m w.d.) in the south. Our results show that provenance supply and current transport directly control the clay mineralogical compositions in core and surface sediments, with various expression forms in different locations. In the north, the clay mineral assemblage indicates a relationship between surface current transport (for smectite) under the significant influence of the Kuroshio intrusion and deep water transport (for illite and chlorite). In the west, the East Asian monsoons forced surface currents and different clay-composition provenances affect the glacial-interglacial cyclicity of clay mineral variations. In the south, land-sea distribution variations controlled by the sea level change determine the sources of clay minerals. Our new studies suggest that the late Quaternary clay minerals in the South China Sea do not bear contemporaneous paleoclimatic features, and their implication for proxies of the East Asian monsoon evolution is realized through both the provenance supply and current transport processes.

  3. Characterisation of the wall-slip during extrusion of heavy-clay products

    NASA Astrophysics Data System (ADS)

    Kocserha, I.; Gömze, A. L.; Kulkov, S.; Kalatur, E.; Buyakova, S. P.; Géber, R.; Buzimov, A. Y.

    2017-01-01

    During extrusion through the extrusion die, heavy-clay compounds are usually show plug flow with extensive slip at the wall of the die. In this study, the viscosity and the thickness of the slip layer were investigated. For the examination a brick-clay from Malyi (Hungary) deposit was applied as a raw material. The clay was characterised by XRPD, BET, SEM and granulometry. As the slip layer consists of suspension of the fine clay fraction so the clay minerals content of the clay (d<2µm) was separated by the help of sedimentation. The viscosity of suspension with different water content was measured by means of rotational viscosimeter. The thickness of the slip layer was calculated from the measured viscosity and other data obtained from an earlier study with capillary rheometer. The calculated thickness value showed a tendency to reach a limit value by increasing the extrusion speed.

  4. A research on the radiation shielding effects of clay, silica fume and cement samples

    NASA Astrophysics Data System (ADS)

    Akbulut, Suat; Sehhatigdiri, Arvin; Eroglu, Hayrettin; Çelik, Semet

    2015-12-01

    Nowadays, as the application areas of nuclear technology increases, protection from radiation has become even more important. Especially, the importance of radiation-shielding is important for the environment and employees which are in close proximity. Clays can be used as additives for shielding the radioactive materials. In this study, the shielding properties of micronize clay-white cement, clay-silica fume, gypsum, gypsum-silica fume, cement, white cement, cement-silica fume, white cement-gypsum, white cement-silica fume, red mud-silica fume, silica fume and red mud at different energy levels were examined. Additionally, compaction and unconfined compression tests were carried out on the samples. The results of clays and other samples were compared with each other. As a result, it was found that clays, especially clay-white cement mixture were superior than other samples in radioactive shielding.

  5. An R package for statistical provenance analysis

    NASA Astrophysics Data System (ADS)

    Vermeesch, Pieter; Resentini, Alberto; Garzanti, Eduardo

    2016-05-01

    This paper introduces provenance, a software package within the statistical programming environment R, which aims to facilitate the visualisation and interpretation of large amounts of sedimentary provenance data, including mineralogical, petrographic, chemical and isotopic provenance proxies, or any combination of these. provenance comprises functions to: (a) calculate the sample size required to achieve a given detection limit; (b) plot distributional data such as detrital zircon U-Pb age spectra as Cumulative Age Distributions (CADs) or adaptive Kernel Density Estimates (KDEs); (c) plot compositional data as pie charts or ternary diagrams; (d) correct the effects of hydraulic sorting on sandstone petrography and heavy mineral composition; (e) assess the settling equivalence of detrital minerals and grain-size dependence of sediment composition; (f) quantify the dissimilarity between distributional data using the Kolmogorov-Smirnov and Sircombe-Hazelton distances, or between compositional data using the Aitchison and Bray-Curtis distances; (e) interpret multi-sample datasets by means of (classical and nonmetric) Multidimensional Scaling (MDS) and Principal Component Analysis (PCA); and (f) simplify the interpretation of multi-method datasets by means of Generalised Procrustes Analysis (GPA) and 3-way MDS. All these tools can be accessed through an intuitive query-based user interface, which does not require knowledge of the R programming language. provenance is free software released under the GPL-2 licence and will be further expanded based on user feedback.

  6. Effects of an iron-silicon material, a synthetic zeolite and an alkaline clay on vegetable uptake of As and Cd from a polluted agricultural soil and proposed remediation mechanisms.

    PubMed

    Yao, Aijun; Wang, Yani; Ling, Xiaodan; Chen, Zhe; Tang, Yetao; Qiu, Hao; Ying, Rongrong; Qiu, Rongliang

    2017-04-01

    Economic and highly effective methods of in situ remediation of Cd and As polluted farmland in mining areas are urgently needed. Pot experiments with Brassica chinensis L. were carried out to determine the effects of three soil amendments [a novel iron-silicon material (ISM), a synthetic zeolite (SZ) and an alkaline clay (AC)] on vegetable uptake of As and Cd. SEM-EDS and XRD analyses were used to investigate the remediation mechanisms involved. Amendment with ISM significantly reduced the concentrations of As and Cd in edible parts of B. chinensis (by 84-94 % and 38-87 %, respectively), to levels that met food safety regulations and was much lower than those achieved by SZ and AC. ISM also significantly increased fresh biomass by 169-1412 % and 436-731 % in two consecutive growing seasons, while SZ and AC did not significantly affect vegetable growth. Correlation analysis suggested that it was the mitigating effects of ISM on soil acidity and on As and Cd toxicity, rather than nutrient amelioration, that contributed to the improvement in plant growth. SEM-EDS analysis showed that ISM contained far more Ca, Fe and Mn than did SZ or AC, and XRD analysis showed that in the ISM these elements were primarily in the form of silicates, oxides and phosphates that had high capacities for chemisorption of metal(loid)s. After incubation with solutions containing 800 mg L(-1) AsO4(2-) or Cd(2+), ISM bound distinctly higher levels of As (6.18 % in relative mass percent by EDS analysis) and Cd (7.21 % in relative mass percent by EDS analysis) compared to SZ and AC. XRD analysis also showed that ISM facilitated the precipitation of Cd(2+) as silicates, phosphates and hydroxides, and that arsenate combined with Fe, Al, Ca and Mg to form insoluble arsenate compounds. These precipitation mechanisms were much more active in ISM than in SZ or AC. Due to the greater pH elevation caused by the abundant calcium silicate, chemisorption and precipitation mechanisms in ISM

  7. Water recovery and disposal of clay waste slimes

    SciTech Connect

    Scheiner, B.J.; Smelley, A.G.

    1980-12-01

    As a part of research conducted in its mission to effect pollution abatement, the Bureau of Mines, U.S. Department of the Interior, is developing a dewatering technique that allows for disposal of mineral wastes, for reuse of water now lost with these wastes, and for reclamation of mined land. The technique utilizes a high-molecular-weight nonionic polyethylene oxide polymer (PEO) that has the ability to flocculate and dewater materials containing clay wastes. A variety of different clay wastes have been successfully dewatered in laboratory experiments. Coal-clay waste was consolidated from 4 to 57 weight-percent; potash-clay brine waste from 20 to 62 weight-percent; phosphatic clay waste from 16 to 49 weight-percent; uranium mill tailings from 15 to 67 weight-percent; talc tailings from 10 to 53 weight-percent. The consolidated materials can be handled by mechanical devices such as trucks and conveyors for disposal in mined-out areas.

  8. Clay platelet partition within polymer blend nanocomposite films by EFTEM.

    PubMed

    Linares, Elisângela M; Rippel, Márcia M; Galembeck, Fernando

    2010-12-01

    Transmission electron microscopy (TEM) is the main technique used to investigate the spatial distribution of clay platelets in polymer nanocomposites, but it has not often been successfully used in polymer blend nanocomposites because the high contrast between polymer phases impairs the observation of clay platelets. This work shows that electron spectral imaging in energy-filtered TEM (EFTEM) in the low-energy-loss spectral crossover region allows the observation of platelets on a clear background. Separate polymer domains are discerned by imaging at different energy losses, above and below the crossover energy, revealing the material morphology. Three blends (natural rubber [NR]/poly(styrene-butyl acrylate) [P(S-BA)], P(S-BA)/poly(vinyl chloride) [PVC], and NR/starch) were studied in this work, showing low contrast between the polymer phases in the 40-60 eV range. In the NR/P(S-BA) and P(S-BA)/PVC blend nanocomposites, the clay platelets accumulate in the P(S-BA) phase, while in the P(S-BA)/PVC nanocomposites, clay is also found at the interfaces. In the NR/starch blend, clay concentrates at the interface, but it also penetrates the two polymer phases. These observations reveal that nanostructured soft materials can display complex morphochemical patterns that are discerned thanks to the ability of EFTEM to produce many contrast patterns for the same sample.

  9. The influence of clay zones on land subsidence from groundwater pumping.

    PubMed

    Budhu, Muniram; Adiyaman, Ibrahim

    2013-01-01

    The objective of this article is to analyze the influence of clay zones on subsidence from groundwater pumping. Finite element analyses were conducted on a sand-only aquifer and a sand aquifer with two clay zones located at different distances from the well face. A model that accounts for recoverable and nonrecoverable strains was used to simulate the sand and clay. This model couples the groundwater flow with the stress-deformation response of the aquifer materials. Each aquifer was pumped from a single well for a period of 6 months, and then the groundwater level was lowered gradually to an elevation below the elevation of the clay zones and kept there for 10 years. The groundwater level was then raised gradually back to the original elevation over a period of 10 years. The results of the analyses show that the ground surface subsidence profile is strongly influenced by the presence of the clays zones. The ground surface sags where these clay zones are present resulting in a wavy ground surface profile. Subsidence continued when pumping is stopped, albeit at a much slower rate than during pumping, and when the groundwater level is below the elevation of the clay zones. Clay zones further away from the well face lag the subsidence of clay zones nearer the well face because of lower changes in hydrostatic head. Sags in ground surface subsidence profile from groundwater pumping are indicators of the presence of low hydraulic conductive geological materials.

  10. Using Clay as a Learning Resource for Teaching the History of Science.

    ERIC Educational Resources Information Center

    De Angelis, Joseph M.

    Construction of laboratory equipment from earthenware clay uses art as a way to incorporate the element of science history into an Introductory Physical Science (IPS) unit on distillation. Classroom techniques for working with clay to construct distilling apparatus are outlined. Other supplementary material from the arts, including slide…

  11. Geochemical study (major, trace elements and Pb-Sr-Nd isotopes) of mantle material obducted onto the North African margin (Edough Massif, North Eastern Algeria): Tethys fragments or lost remnants of the Liguro-Provençal basin?

    NASA Astrophysics Data System (ADS)

    Bosch, Delphine; Hammor, Dalila; Mechati, Mehdi; Fernandez, Laure; Bruguier, Olivier; Caby, Renaud; Verdoux, Patrick

    2014-06-01

    The Maghrebides, Betics and some parts of the Calabrian, NE Sicilian and Tuscan allochtons constitute dismembered fragments of the Alpine belt that resulted from the Cenozoic collision between Africa and Eurasia and the opening of the Western Mediterranean basin. Mineral and whole-rock geochemical analyses have been performed on three distinct outcrops of mantle material from the Edough Massif of NE Algeria, namely the Bou Maiza (BM) gabbros, the La Voile Noire (LVN) amphibolites and the Sidi Mohamed (SM) peridotites. In all samples, Sr isotopes are largely affected by seawater alteration (87Sr/86Sract. > 0.70384 and up to 0.70888) and cannot be used to evaluate the nature of the source reservoirs. SM peridotites display variable depleted mantle Nd isotopic signatures (εNdact. from + 7.0 to + 12.2) and geochemical features suggesting no significant chemical depletion as a result of partial melting and melt extraction (Mg# < 90; slightly LREE-depleted patterns with La/YbN = 0.33-0.39). These rocks are interpreted as parts of the subcontinental lithospheric mantle incorporated into the crustal units of the Edough Massif during the early stages of opening of the Algerian basin. BM gabbros and LVN amphibolites show geochemical signatures indicating derivation from a common depleted mantle reservoir (εNd > + 7.9) and are likely cogenetic, but without filiation with the SM peridotites. Pb isotopes indicate a contribution of sediments in the source reservoir, which is attributed to contamination solely by hydrous fluids released from a sedimentary component. This observation, together with a LILE-enrichment, suggests a back-arc basin environment. These results indicate that BM and LVN units were obducted onto the North African margin and subsequently fragmented, probably during doming and exhumation of the lower continental crust of the Edough massif. Doming resulted in opposite movements of the overlying oceanic units, southward for the BM units and northward for LVN

  12. Influence of sea level change on sediment provenance variations since the last glaciation in the southern South China Sea

    NASA Astrophysics Data System (ADS)

    Jiwarungrueangkul, T.; Liu, Z.; Zhao, Y.

    2015-12-01

    Clay mineralogy and grain size of 170 sediment samples from Core MD05-2893 located near the Molengraaff paleo-river mouth on the upper Sunda slope in the southern South China Sea were investigated to assess the effect of sea level change on sediment provenance variations. The clay mineral results show high contents of smectite (35-55%), moderate contents of illite (16-31%), kaolinite (11-29%), and chlorite (8-15%). Due to distinction of clay mineral assemblages from each sediment provenance, the Indonesian Archipelago is the majority of smectite source, whereas North Boneo mainly provides illite to the southern South China Sea. Therefore, the smectite/illite ratio is applied to determine the sediment provenance variations. Both the mineralogical ratio and median grain size show consistent sediment source and dynamic variations since the last glaciation, in which case the response of sediment provenance change due to the sea level rise is expected. Our study suggests a three-stage evolution of the sediment provenance variation on the Sunda slope in the southern South China Sea: (1) during the low sea level stand of the last glaciation, the high content of smectite implies that the Indonesian Archipelago provided the majority of sediments to this area through the Molengraaff paleo-river system; (2) during the sea level rise of the deglaciation, the decreasing of smectite content but the increasing of illite indicates that the Indonesian Archipelago reduced in sediments supply due to regression of coastline, whereas North Boneo increased sediment supply; (3) during the high sea level stand of Holocene, the smectite content increases again, implying that the Indonesian Archipelago provides sediments to this area again through the ocean circulation. Consequently, the sea level rise mainly results in sediment provenance change in the southern South China Sea since the last deglaciation.

  13. Geochemical characteristics of the Miocene eolian deposits in China: Their provenance and climate implications

    NASA Astrophysics Data System (ADS)

    Liang, Meiyan; Guo, Zhengtang; Kahmann, A. Julia; Oldfield, Frank

    2009-04-01

    In the Loess Plateau in northern China, the Quaternary loess-soil sequences, the Hipparion Red Earth of eolian origin (Red Clay), and the Miocene loess-soil sequences constitute a near-continuous terrestrial record of paleoclimates for the past 22 Ma. In this study, Miocene loess and paleosol samples from Qinan (QA-I) were analyzed for their major, trace, and rare earth element chemistry and compared with the Plio-Pleistocene samples from Xifeng with emphasis on their provenance and paleoclimatic implications. The results show similar geochemical signatures for the eolian deposits of different ages, and they are also comparable to the average composition of the upper continental crust. These suggest that the dust materials were all derived from well-mixed sedimentary protoliths which had undergone numerous upper crustal recycling processes. They also support the notion of broadly similar source areas and dust-transporting trajectories for different periods since the early Neogene. The slightly higher K2O, Fe2O3, and MgO concentrations and loss on ignition values and the lower Na2O content in the Miocene loess samples compared to their Quaternary counterparts are attributable to the finer grain size of the Miocene loess associated with weaker dust-carrying winds. In comparison with some loess in Europe and America with less extensive sources, eolian deposits from northern China show higher Cs and lower Zr and Hf content. This is attributable to the sorting processes from remoter sources during transportation and could be regarded as an indication of the desert origin of the loess deposits. Miocene paleosol samples show higher chemical index of alteration values and lower CaO, MgO, and Na2O concentrations than does the intervening loess, indicating stronger weathering of the paleosols. However, the moderate chemical weathering of the paleosol samples indicates a constant semiarid and subhumid climatic range in northern China since the early Miocene.

  14. Evaluation of filesystem provenance visualization tools.

    PubMed

    Borkin, Michelle A; Yeh, Chelsea S; Boyd, Madelaine; Macko, Peter; Gajos, Krzysztof Z; Seltzer, Margo; Pfister, Hanspeter

    2013-12-01

    Having effective visualizations of filesystem provenance data is valuable for understanding its complex hierarchical structure. The most common visual representation of provenance data is the node-link diagram. While effective for understanding local activity, the node-link diagram fails to offer a high-level summary of activity and inter-relationships within the data. We present a new tool, InProv, which displays filesystem provenance with an interactive radial-based tree layout. The tool also utilizes a new time-based hierarchical node grouping method for filesystem provenance data we developed to match the user's mental model and make data exploration more intuitive. We compared InProv to a conventional node-link based tool, Orbiter, in a quantitative evaluation with real users of filesystem provenance data including provenance data experts, IT professionals, and computational scientists. We also compared in the evaluation our new node grouping method to a conventional method. The results demonstrate that InProv results in higher accuracy in identifying system activity than Orbiter with large complex data sets. The results also show that our new time-based hierarchical node grouping method improves performance in both tools, and participants found both tools significantly easier to use with the new time-based node grouping method. Subjective measures show that participants found InProv to require less mental activity, less physical activity, less work, and is less stressful to use. Our study also reveals one of the first cases of gender differences in visualization; both genders had comparable performance with InProv, but women had a significantly lower average accuracy (56%) compared to men (70%) with Orbiter.

  15. Boron enrichment in martian clay.

    PubMed

    Stephenson, James D; Hallis, Lydia J; Nagashima, Kazuhide; Freeland, Stephen J

    2013-01-01

    We have detected a concentration of boron in martian clay far in excess of that in any previously reported extra-terrestrial object. This enrichment indicates that the chemistry necessary for the formation of ribose, a key component of RNA, could have existed on Mars since the formation of early clay deposits, contemporary to the emergence of life on Earth. Given the greater similarity of Earth and Mars early in their geological history, and the extensive disruption of Earth's earliest mineralogy by plate tectonics, we suggest that the conditions for prebiotic ribose synthesis may be better understood by further Mars exploration.

  16. Boron Enrichment in Martian Clay

    PubMed Central

    Nagashima, Kazuhide; Freeland, Stephen J.

    2013-01-01

    We have detected a concentration of boron in martian clay far in excess of that in any previously reported extra-terrestrial object. This enrichment indicates that the chemistry necessary for the formation of ribose, a key component of RNA, could have existed on Mars since the formation of early clay deposits, contemporary to the emergence of life on Earth. Given the greater similarity of Earth and Mars early in their geological history, and the extensive disruption of Earth's earliest mineralogy by plate tectonics, we suggest that the conditions for prebiotic ribose synthesis may be better understood by further Mars exploration. PMID:23762242

  17. Geological and technological characterization of the Late Jurassic-Early Cretaceous clay deposits (Jebel Ammar, northeastern Tunisia) for ceramic industry

    NASA Astrophysics Data System (ADS)

    Ben M'barek-Jemaï, Moufida; Sdiri, Ali; Ben Salah, Imed; Ben Aissa, Lassaad; Bouaziz, Samir; Duplay, Joelle

    2017-05-01

    Late Jurassic-Lower Cretaceous clays of the Jebel Ammar study site were used as raw materials for potential applications in ceramic industry. Physico-chemical characterization of the collected samples was performed using atomic absorption spectroscopy, X-ray diffraction, thermogravimetry and dilatometry (Bugot's curve). Geotechnical study was also undertaken by the assessment of plasticity and liquidity limits. It was found that high concentrations of silica, alumina with SiO2/Al2O3 ratio characterized the studied clays; its high amounts of CaO and Fe2O3 in the Late Jurassic clays indicated their calcareous nature. In addition, technological tests indicated moderate to low plasticity values for the Late Jurassic and Lower Cretaceous clays, respectively. Clay fraction (<2 μm) reached 50% of the natural clay in some cases. Mineralogical analysis showed that Jurassic clays were dominated by smectite, illite and kaolinite, as clay mineral species; calcite was the main associated mineral. Lower Cretaceous clays were mainly composed of abundant illite accompanied by well-crystallized smectite and kaolinite. Kaolinite gradually increased upwards, reaching 70% of the total clay fraction (i.e. <2 μm). Quartz, calcite and feldspar were the main non-clay minerals. Based on these analyses, the clays meet technological requirements that would allow their use in the ceramic industry and for the manufacturing of ceramic tiles.

  18. Investigating the Influence of Clay Mineralogy on Stream Bank Erodibility

    NASA Astrophysics Data System (ADS)

    Ambers, R. K.; Stine, M. B.

    2005-12-01

    Soil scientists concerned with erosion of agricultural fields and geotechnical engineers concerned with the mechanical behavior of soils under different conditions have both examined the role of clay mineralogy in controlling soil/sediment properties. Fluvial geomorphologists studying stream channel erosion and stability have focused more on the effects of particle-size distribution, vegetation and rooting. The clay mineralogy of bed and bank sediment has the potential to influence cohesiveness and erodibility, however. The goal of this study is to determine the influence of clay mineralogy on the erodibility of natural stream bank sediment, utilizing techniques drawn from pedology and soil mechanics. Bank samples were collected from eleven sites in small watersheds in central and western Virginia. To obtain sediment containing a range of different clay minerals, watersheds with different types of bedrock were chosen for sampling. Rock types included mafic to felsic metamorphic and igneous rocks, shale, sandstone, and limestone. Where stream bank materials were clearly stratified, different layers were sampled separately. X-ray diffraction of the clay-fraction of the sediment indicates the presence of kaolinite, illite, vermiculite, and mixed-layer clay minerals in various abundances in the different samples. Clay content is 9-46%, as determined by the hydrometer method, and textures range from silty clay and silt loam to clay loam and sandy loam. Organic mater contents range from 1-5% by the loss-on-ignition method. Bulk density of intact sediment samples averages 1.5 g/cc. Liquid limits range from 23-41 with one sample having a value of 65; plasticity indices range from 15-22. While these tests predict that the samples would show a range of mechanical behaviors, the channel morphology at the sampling sites was not strikingly different, all having steep cut banks eroded primarily by scour with no evidence of mass movement and most having a width/depth ratio around

  19. Interaction of Uranium Mill Tailings Leachate with Soils and Clay Liners

    SciTech Connect

    Gee, G. W.; Campbell, A. C.; Sherwood, D. R.; Strickert, R. G.; Phillips, S. J.

    1980-06-01

    This study evaluates leachate-soil interactions that will take place at the Morton Ranch for certain disposal alternatives. Laboratory tests were conducted to evaluate the following: 1) physical and chemical characteristics of geologic materials from the Morton Ranch. 2) physical and chemical characteristics of acid leach tailings and tallings solution, 3) leaching tests with selected tailings materials and leach solutions to evaluate the leachability of contaminants with time under specific disposal alternatives, 4) adsorption studies measuring the sorption characteristics of heavy metals and radionuclides on the geologic materials at Morton Ranch, 5) clay liner stability tests to evaluate effects of acid leachate on clay mineralogy and clay permeability.

  20. Development and Characterization of Cellulose/clay Nanocomposites

    USDA-ARS?s Scientific Manuscript database

    Cotton is the most important textile fiber for apparel use and is preferred to synthetic fibers for reasons such as comfort and feel. A major drawback of cellulosic fibers is flammability. The development of cellulose/clay nanocomposites for use as flame retardant materials based on cotton is repo...

  1. Clay Mineralogy and Organic Carbon Burial in Proterozoic Basins

    NASA Astrophysics Data System (ADS)

    Tosca, N. J.; Johnston, D. T.; Mushegian, A.; Rothman, D. H.; Knoll, A. H.

    2008-12-01

    Pedogenic, or soil-derived, clay minerals have long been implicated in the efficiency of organic matter (OM) burial and coincident accumulation of atmospheric oxygen. As diagenesis and metamorphism obscure pedogenic clays in many Precambrian rocks, clay mineralogy and its role in OM burial through much of geologic time remains incompletely understood. In this study we analyzed the mineralogy and total organic carbon (TOC) of a number of organic rich shales deposited in Late Archean to Early Cambrian sedimentary basins. Across all samples, diagenetic transformation of pre-existing smectite minerals has led to the predominance of glauconite and the diagenetic 1M and 1Md illite polytypes, which, collectively, can be thought of as "proto-smectite". The correlations between TOC and illite crystallinity suggest that OM burial and preservation in the Proterozoic proceeded by the physical aggregation of OM and pedogenic clays upon deposition. This association, in turn, led to the interference of OM with the illitization process, resulting in the ubiquitous relationship between high surface area (or, finely crystalline) material and high TOC. This interpretation is consistent with suggestions that the preservation of OM after burial proceeds by physical exclusion, with mineral surfaces effectively isolating OM from enzymatic breakdown. Together, it appears that the deposition of pedogenic clays has remained broadly constant over Proterozoic time and into the Early Cambrian, which is incompatible with the hypothesis that late Neoproterozoic oxygenation was influenced by increases in pedogenic clay production. As no clear temporal relationship exists between clays and OM, Precambrian oxygenation was likely controlled by other mechanisms.

  2. Community Education Proven Practices II: Networking Strategies.

    ERIC Educational Resources Information Center

    Arkansas State Dept. of Education, Little Rock.

    Designed to be used by those who wish to initiate or further develop community education programs at the state and local levels, this publication is one of a series of "Proven Practices" developed by federally-funded state and local community education projects. The booklet describes the administrative design and the process used to…

  3. Applying Content Management to Automated Provenance Capture

    SciTech Connect

    Schuchardt, Karen L.; Gibson, Tara D.; Stephan, Eric G.; Chin, George

    2008-04-10

    Workflows and data pipelines are becoming increasingly valuable in both computational and experimen-tal sciences. These automated systems are capable of generating significantly more data within the same amount of time than their manual counterparts. Automatically capturing and recording data prove-nance and annotation as part of these workflows is critical for data management, verification, and dis-semination. Our goal in addressing the provenance challenge was to develop and end-to-end system that demonstrates real-time capture, persistent content management, and ad-hoc searches of both provenance and metadata using open source software and standard protocols. We describe our prototype, which extends the Kepler workflow tools for the execution environment, the Scientific Annotation Middleware (SAM) content management software for data services, and an existing HTTP-based query protocol. Our implementation offers several unique capabilities, and through the use of standards, is able to pro-vide access to the provenance record to a variety of commonly available client tools.

  4. Provenance testing at Michigan Technological University

    Treesearch

    Robert L. Sajdak

    1970-01-01

    The location of M.T.U. in the Keweenaw Peninsula of Upper Michigan provides some unique advantages and disadvantages in provenance testing and tree improvement research. Extremes in summer and winter temperatures are uncommon because of the moderating effect of Lake Superior. Near the Lake we have about 140 frost-free days while inland the frost-free season is only 80...

  5. [Species Determination and Spectral Characteristics of Swelling Clay Minerals in the Pliocene Sandstones in Xinghai, Qinghai].

    PubMed

    Wang, Chao-wen; Chen, Jiang-jun; Fang, Qian; Yin, Ke; Hong, Han-lie

    2015-10-01

    X-ray diffraction (XRD) and Fourier infrared absorption spectroscopy (FTIR) were conducted to deepen our research on specific species and spectral characteristics of swelling clay minerals in the Pliocene sandstones in Xinghai, Qinghai province. XRD results show that swelling clay minerals are dominant clay minerals in the sandstones, which can be up to 97% in percentage. XRD patterns show 060 reflections of the samples occur both remarkably at 1.534 Å and 1.498 Å, indicating the samples contain physical mixtures of trioctahedral and dioctahedral swelling clay minerals, respectively. Further treatment of Li-300 degrees C heat and glycerol saturation shows the swelling clay minerals collapse to 9.3-9.9 Å with a partial expansion to -18 Å. This indicates the swelling clay minerals dominate montmorillonite and contain minor saponite. The montmorillonite shows no swelling after Li-300 degrees C heat and glycerol saturation because of Li+ inserting into the octahedral layers, which balances the layer charge caused by the substitution of Mg to Al. FTIR results show the samples are composed of a kind of phyllosilicate with absorbed and structural water, which is in agreement with the results of XRD. Absorbed peaks at 913, 842, 880 cm(-1), corresponding to OH associated with Al-Al, Al-Mg, and Al-Fe pairs, further indicates the minerals are dominant dioctahedron in structure. Meanwhile, absorbed peaks at 625 and 519 cm(-1), corresponding to coupled Si-O and Al-O-Si deformation, indicates parts of Si is replaced by Al in tetrahedron. The spectral characteristics of the samples are against the presence of beidellite and nontronite based on the results of XRD and FTIR, while demonstrating an,existence of montmorillonite. This study, to distinguish the specific species of swelling clay species in clay minerals, would be of great importance when using clay mineralogy to interpret provenance and climatic information.

  6. A Study on Sorption of (226)Ra on Different Clay Matrices.

    PubMed

    Alhajji, E; Al-Masri, M S; Khalily, H; Naoum, B E; Khalil, H S; Nashawati, A

    2016-08-01

    The sorption of radium 226 ((226)Ra) on different clay materials (bentonite, illite and a mixture of bentonite-illite) was studied. Clay materials are used in the construction of disposal pits for technically enhanced naturally occurring radioactive materials (TENORM) wastes (i.e., contaminated soil and sludge) generated by the oil and gas industry operations. Experimental conditions (pH, clay materials quantity, and activity concentrations of (226)Ra) were changed in order to determine the optimal state for adsorption of (226)Ra. The results showed that the concentration of adsorbed (226)Ra on clay materials increased with time to reach an equilibrium state after approximately 5 h. More than 95 % of the radium was adsorbed. The mixture of bentonite-illite (1/9) exhibited the greatest adsorption of radium under all experimental conditions.

  7. Distributions of clay minerals in surface sediments of the middle Bay of Bengal: Source and transport pattern

    NASA Astrophysics Data System (ADS)

    Li, Jingrui; Liu, Shengfa; Shi, Xuefa; Feng, Xiuli; Fang, Xisheng; Cao, Peng; Sun, Xingquan; Wenxing, Ye; Khokiattiwong, Somkiat; Kornkanitnan, Narumol

    2017-08-01

    The clay mineral contents in 110 surface sediment samples collected from the middle of the Bay of Bengal were analyzed by X-ray diffraction (XRD) to investigate the provenance and transport patterns. The illite content was highest, followed by chlorite, kaolinite and then smectite, with average weight percent distributions of 52%, 22%, 14% and 12%, respectively. Illite and chlorite had similar distribution pattern, with higher contents in the northern and central areas and lower contents in the southern area, whereas smectite showed the opposite distribution pattern. Kaolinite show no obvious higher or lower areas and the southern ;belt; was one of the highest content areas. Based on the spatial distribution characteristics and cluster analysis results, the study area can be classified into two provinces. Province I covers the southwestern area and contains high concentrations of illite and smectite sediments. Province II covers most sites and is also characterized by high concentrations of illite, but the weight percent of smectite is only half of that of province I. According to a quantitative estimate using end-member clay minerals contents, the relative contributions from the Himalayan source and the Indian source are 63% and 37% on average, respectively. Integrative analysis indicates that the hydrodynamic environment in the study area, especially the turbidity and surface monsoonal circulation, plays an important role in the spatial distribution and dispersal of the clay fraction in the sediments. The sediments in province I are mainly from the Indian source transported by the East Indian Coastal Current (EICC) and the surface monsoon circulation with minor contributions from the Himalayan source while the sediments in province II are mainly from the Himalayan source transported by turbidity and surface monsoonal circulation with little contribution from Indian river materials.

  8. Picasso Masks: Cubism in Clay

    ERIC Educational Resources Information Center

    Daddino, Michelle

    2010-01-01

    This article describes an art project developed by the author which provides a way to further the children's understanding of Picasso's Cubism style in 3-D. Through this project, upper-elementary students learn a bit about the life and art of Picasso as they gain a firm understanding of the style of art known as Cubism, and apply clay techniques…

  9. ADSORPTION OF SURFACTANT ON CLAYS

    EPA Science Inventory

    Surfactants used to enhance remediation of soils by soil washing are often lost in the process. Neither the amount nor the cause of this loss is known. It is assumed that clays present in the soil are responsible for the loss of the surfactant. In this papere, adsorption prope...

  10. ADSORPTION OF SURFACTANT ON CLAYS

    EPA Science Inventory

    Surfactants used to enhance remediation of soils by soil washing are often lost in the process. Neither the amount nor the cause of this loss is known. It is assumed that clays present in the soil are responsible for the loss of the surfactant. In this papere, adsorption prope...

  11. Picasso Masks: Cubism in Clay

    ERIC Educational Resources Information Center

    Daddino, Michelle

    2010-01-01

    This article describes an art project developed by the author which provides a way to further the children's understanding of Picasso's Cubism style in 3-D. Through this project, upper-elementary students learn a bit about the life and art of Picasso as they gain a firm understanding of the style of art known as Cubism, and apply clay techniques…

  12. Multifunctional epoxy composites with natural Moroccan clays

    NASA Astrophysics Data System (ADS)

    Monsif, M.; Zerouale, A.; Kandri, N. Idrissi; Allali, F.; Sgarbossa, P.; Bartolozzi, A.; Tamburini, S.; Bertani, R.

    2016-05-01

    Two natural Moroccan clays, here firstly completely characterized, have been used as fillers without modification in epoxy composites. Mechanical properties resulted to be improved and a significant antibacterial activity is exhibited by the epoxy composite containing the C2 clay.

  13. Stools - pale or clay-colored

    MedlinePlus

    ... gov/ency/article/003129.htm Stools - pale or clay-colored To use the sharing features on this page, please enable JavaScript. Stools that are pale, clay, or putty-colored may be due to problems ...

  14. Effect of sonication on the particle size of montmorillonite clays.

    PubMed

    Poli, Alessandra L; Batista, Tatiana; Schmitt, Carla C; Gessner, Fergus; Neumann, Miguel G

    2008-09-15

    This paper reports on the effect of sonication on SAz-1 and SWy-1 montmorillonite suspensions. Changes in the size of the particles of these materials and modifications of their properties have been investigated. The variation of the particle size has been analyzed by DLS (dynamic light scattering). In all cases the clay particles show a bimodal distribution. Sonication resulted in a decrease of the larger modal diameter, as well as a reduction of its volume percentage. Simultaneously, the proportion of the smallest particles increases. After 60 min of sonication, SAz-1 presented a very broad particle size distribution with a modal diameter of 283 nm. On the other hand, the SWy-1 sonicated for 60 min presents a bimodal distribution of particles at 140 and 454 nm. Changes in the properties of the clay suspensions due to sonication were evaluated spectroscopically from dye-clay interactions, using Methylene Blue. The acidic sites present in the interlamellar region, which are responsible for dye protonation, disappeared after sonication of the clay. The changes in the size of the scattering particles and the lack of acidic sites after sonication suggest that sonication induces delamination of the clay particles.

  15. Direct visualization of clay microfabric signatures driving organic matter preservation in fine-grained sediment

    NASA Astrophysics Data System (ADS)

    Curry, Kenneth J.; Bennett, Richard H.; Mayer, Lawrence M.; Curry, Ann; Abril, Maritza; Biesiot, Patricia M.; Hulbert, Matthew H.

    2007-04-01

    We employed direct visualization of organic matter (OM) sequestered by microfabric signatures in organo-clay systems to study mechanisms of OM protection. We studied polysaccharides, an abundant class of OM in marine sediments, associated with the nano- and microfabric of clay sediment using a novel application of transmission electron microscopy, histochemical staining (periodic acid-thiosemicarbazide-silver proteinate), and enzymatic digestion techniques. We used two experimental organo-clay sediment environments. First, laboratory-consolidated sediment with 10% chitin (w/w) added was probed for chitin before and after digestion with chitinase. Second, fecal pellets from the polychaete Heteromastus filiformis were used as a natural environment rich in clay and polysaccharides. Sections of this material were probed with silver proteinate for polysaccharides before and after digestion with a mixture of enzymes (amylase, cellulase, chitinase, dextranase, and pectinase). In both environments, chitin or other polysaccharides were found within pores, bridging clay domains, and attached to clay surfaces in undigested samples. Digested samples showed chitin or polysaccharides more closely associated with clay surfaces and in small pores. Our results imply protective roles for both sorption to clay surfaces and encapsulation within clay microfabric signatures.

  16. Hydraulic conductivity of compacted clay liners permeated with inorganic salt solutions.

    PubMed

    Yilmaz, Gonca; Yetimoglu, Temel; Arasan, Seracettin

    2008-10-01

    Due to their low permeability, geosynthetic clay liners (GCLs) and compacted clay liners (CCLs) are the main materials used in waste disposal landfills. The hydraulic conductivity of GCLs and CCLs is closely related to the chemistry of the permeant fluid. In this study, the effect on the hydraulic conductivity of clays of five different inorganic salt solutions as permeant fluid was experimentally investigated. For this purpose, NaCl, NH(4)Cl, KCl, CaCl(2), and FeCl( 3) inorganic salt solutions were used at concentrations of 0.01, 0.10, 0.25, 0.50, 0.75 and 1 M. Laboratory hydraulic conductivity tests were conducted on low plasticity (CL) and high plasticity (CH) compacted raw clays. The change in electrical conductivity and pH values of the clay samples with inorganic salt solutions were also determined. The experimental test results indicated that the effect of inorganic salt solutions on CL clay was different from that on CH clay. The hydraulic conductivity was found to increase for CH clay when the salt concentrations increased whereas when the salt concentrations were increased, the hydraulic conductivity decreased for the CL clay.

  17. Mineral resource of the month: clays

    USGS Publications Warehouse

    Virta, Robert

    2004-01-01

    Clays represent one of the largest mineral commodities in the world in terms of mineral and rock production and use. Many people, however, do not recognize that clays are used in an amazingly wide variety of applications. Use continues to increase worldwide as populations and their associated needs increase. Robert Virta, clay and shale commodity specialist for the U.S. Geological Survey, has prepared the following information about clays.

  18. 21 CFR 186.1256 - Clay (kaolin).

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Clay (kaolin). 186.1256 Section 186.1256 Food and... Substances Affirmed as GRAS § 186.1256 Clay (kaolin). (a) Clay (kaolin) Al2O3.2SiO2.nH2O, Cas Reg. No. 1332-58-7) consists of hydrated aluminum silicate. The commercial products of clay (kaolin) contain...

  19. Unraveling the antibacterial mode of action of a clay from the Colombian Amazon.

    PubMed

    Londono, Sandra Carolina; Williams, Lynda B

    2016-04-01

    Natural antibacterial clays can inhibit growth of human pathogens; therefore, understanding the antibacterial mode of action may lead to new applications for health. The antibacterial modes of action have shown differences based on mineralogical constraints. Here we investigate a natural clay from the Colombian Amazon (AMZ) known to the Uitoto natives as a healing clay. The physical and chemical properties of the AMZ clay were compared to standard reference materials: smectite (SWy-1) and kaolinite (API #5) that represent the major minerals in AMZ. We tested model Gram-negative (Escherichia coli ATCC #25922) and Gram-positive (Bacillus subtilis ATCC #6633) bacteria to assess the clay's antibacterial effectiveness against different bacterial types. The chemical and physical changes in the microbes were examined using bioimaging and mass spectrometry of clay digests and aqueous leachates. Results indicate that a single dose of AMZ clay (250 mg/mL) induced a 4-6 order of magnitude reduction in cell viability, unlike the reference clays that did not impact bacterial survival. AMZ clay possesses a relatively high specific surface area (51.23 m(2)/g) and much higher total surface area (278.82 m(2)/g) than the reference clays. In aqueous suspensions (50 mg clay/mL water), soluble metals are released and the minerals buffer fluid pH between 4.1 and 4.5. We propose that the clay facilitates chemical interactions detrimental to bacteria by absorbing nutrients (e.g., Mg, P) and potentially supplying metals (e.g., Al) toxic to bacteria. This study demonstrates that native traditional knowledge can direct scientific studies.

  20. Physicochemical of pillared clays prepared by several metal oxides

    NASA Astrophysics Data System (ADS)

    Rinaldi, Nino; Kristiani, Anis

    2017-03-01

    Natural clays could be modified by the pillarization method, called as Pillared Clays (PILCs). PILCs have been known as porous materials that can be used for many applications, one of the fields is catalysis. PILCs as two dimensional materials are interesting because their structures and textural properties can be controlled by using a metal oxide as the pillar. Different metal oxide used as the pillar causes different properties results of pillared clays. Usually, natural smectite clays/bentonites are used as a raw material. Therefore, a series of bentonite pillared by metal oxides was prepared through pillarization method. Variation of metals pillared into bentonite are aluminium, chromium, zirconium, and ferro. The physicochemical properties of catalysts were characterized by using X-ray Diffraction (XRD), Thermo Gravimetric Analysis (TGA), Brunauer-Emmett-Teller (BET) and Barret-Joyner-Halenda (BJH) analysis, and Fourier transform infrared spectroscopy (FTIR) measurement. Noteworthy characterization results showed that different metals pillared into bentonite affected physical and chemical properties, i.e. basal spacing, surface area, pore size distribution, thermal stability and acidity.

  1. Clay & Children: More than Making Pots.

    ERIC Educational Resources Information Center

    Kolbe, Ursula

    1997-01-01

    Working with clay enables young children to express, explore, and communicate their feelings and ideas. This resource booklet for early childhood practitioners and it promotes the clay table as a special place for shared discoveries, social interaction, and discussion. The booklet provides a glossary of terms used in clay work, as well as reasons…

  2. Clay Cuffman: A Cool, Calm, Relaxed Guy

    ERIC Educational Resources Information Center

    Booth, Gina

    2010-01-01

    This article describes Clay Cuffman, a simple clay-sculpture project that requires two or three sessions, and works for students from the upper-elementary level through high school. It takes about 1.5 pounds of clay per student--about the size of a small grapefruit. The Cuffman project is a great way for upper-elementary through high-school…

  3. Clay Cuffman: A Cool, Calm, Relaxed Guy

    ERIC Educational Resources Information Center

    Booth, Gina

    2010-01-01

    This article describes Clay Cuffman, a simple clay-sculpture project that requires two or three sessions, and works for students from the upper-elementary level through high school. It takes about 1.5 pounds of clay per student--about the size of a small grapefruit. The Cuffman project is a great way for upper-elementary through high-school…

  4. Clay & Children: More than Making Pots.

    ERIC Educational Resources Information Center

    Kolbe, Ursula

    1997-01-01

    Working with clay enables young children to express, explore, and communicate their feelings and ideas. This resource booklet for early childhood practitioners and it promotes the clay table as a special place for shared discoveries, social interaction, and discussion. The booklet provides a glossary of terms used in clay work, as well as reasons…

  5. Quantifying the provenance of aeolian sediments using multiple composite fingerprints

    NASA Astrophysics Data System (ADS)

    Liu, Benli; Niu, Qinghe; Qu, Jianjun; Zu, Ruiping

    2016-09-01

    We introduce a new fingerprinting method that uses multiple composite fingerprints for studies of aeolian sediment provenance. We used this method to quantify the provenance of sediments on both sides of the Qinghai-Tibetan Railway (QTR) in the Cuona Lake section of the Tibetan Plateau (TP), in an environment characterized by aeolian and fluvial interactions. The method involves repeatedly solving a linear mixing model based on mass conservation; the model is not limited to spatial scale or transport types and uses all the tracer groups that passed the range check, Kruskal-Wallis H-test, and a strict analytical solution screening. The proportional estimates that result from using different composite fingerprints are highly variable; however, the average of these fingerprints has a greater accuracy and certainty than any single fingerprint. The results show that sand from the lake beach, hilly surface, and gullies contribute, respectively, 48%, 31% and 21% to the western railway sediments and 43%, 33% and 24% to the eastern railway sediments. The difference between contributions from various sources on either side of the railway, which may increase in the future, was clearly related to variations in local transport characteristics, a conclusion that is supported by grain size analysis. The construction of the QTR changed the local cycling of materials, and the difference in provenance between the sediments that are separated by the railway reflects the changed sedimentary conditions on either side of the railway. The effectiveness of this method suggests that it will be useful in other studies of aeolian sediments.

  6. PAV ontology: provenance, authoring and versioning

    PubMed Central

    2013-01-01

    Background Provenance is a critical ingredient for establishing trust of published scientific content. This is true whether we are considering a data set, a computational workflow, a peer-reviewed publication or a simple scientific claim with supportive evidence. Existing vocabularies such as Dublin Core Terms (DC Terms) and the W3C Provenance Ontology (PROV-O) are domain-independent and general-purpose and they allow and encourage for extensions to cover more specific needs. In particular, to track authoring and versioning information of web resources, PROV-O provides a basic methodology but not any specific classes and properties for identifying or distinguishing between the various roles assumed by agents manipulating digital artifacts, such as author, contributor and curator. Results We present the Provenance, Authoring and Versioning ontology (PAV, namespace http://purl.org/pav/): a lightweight ontology for capturing “just enough” descriptions essential for tracking the provenance, authoring and versioning of web resources. We argue that such descriptions are essential for digital scientific content. PAV distinguishes between contributors, authors and curators of content and creators of representations in addition to the provenance of originating resources that have been accessed, transformed and consumed. We explore five projects (and communities) that have adopted PAV illustrating their usage through concrete examples. Moreover, we present mappings that show how PAV extends the W3C PROV-O ontology to support broader interoperability. Method The initial design of the PAV ontology was driven by requirements from the AlzSWAN project with further requirements incorporated later from other projects detailed in this paper. The authors strived to keep PAV lightweight and compact by including only those terms that have demonstrated to be pragmatically useful in existing applications, and by recommending terms from existing ontologies when plausible. Discussion

  7. PAV ontology: provenance, authoring and versioning.

    PubMed

    Ciccarese, Paolo; Soiland-Reyes, Stian; Belhajjame, Khalid; Gray, Alasdair Jg; Goble, Carole; Clark, Tim

    2013-11-22

    Provenance is a critical ingredient for establishing trust of published scientific content. This is true whether we are considering a data set, a computational workflow, a peer-reviewed publication or a simple scientific claim with supportive evidence. Existing vocabularies such as Dublin Core Terms (DC Terms) and the W3C Provenance Ontology (PROV-O) are domain-independent and general-purpose and they allow and encourage for extensions to cover more specific needs. In particular, to track authoring and versioning information of web resources, PROV-O provides a basic methodology but not any specific classes and properties for identifying or distinguishing between the various roles assumed by agents manipulating digital artifacts, such as author, contributor and curator. We present the Provenance, Authoring and Versioning ontology (PAV, namespace http://purl.org/pav/): a lightweight ontology for capturing "just enough" descriptions essential for tracking the provenance, authoring and versioning of web resources. We argue that such descriptions are essential for digital scientific content. PAV distinguishes between contributors, authors and curators of content and creators of representations in addition to the provenance of originating resources that have been accessed, transformed and consumed. We explore five projects (and communities) that have adopted PAV illustrating their usage through concrete examples. Moreover, we present mappings that show how PAV extends the W3C PROV-O ontology to support broader interoperability. The initial design of the PAV ontology was driven by requirements from the AlzSWAN project with further requirements incorporated later from other projects detailed in this paper. The authors strived to keep PAV lightweight and compact by including only those terms that have demonstrated to be pragmatically useful in existing applications, and by recommending terms from existing ontologies when plausible. We analyze and compare PAV with related

  8. Characterizing Provenance in Visualization and Data Analysis: An Organizational Framework of Provenance Types and Purposes

    SciTech Connect

    Ragan, Eric; Alex, Endert; Sanyal, Jibonananda; Chen, Jian

    2016-01-01

    While the primary goal of visual analytics research is to improve the quality of insights and findings, a substantial amount of research in provenance has focused on the history of changes and advances throughout the analysis process. The term, provenance, has been used in a variety of ways to describe different types of records and histories related to visualization. The existing body of provenance research has grown to a point where the consolidation of design knowledge requires cross-referencing a variety of projects and studies spanning multiple domain areas. We present an organizational framework of the different types of provenance information and purposes for why they are desired in the field of visual analytics. Our organization is intended to serve as a framework to help researchers specify types of provenance and coordinate design knowledge across projects. We also discuss the relationships between these factors and the methods used to capture provenance information. In addition, our organization can be used to guide the selection of evaluation methodology and the comparison of study outcomes in provenance research

  9. Characterizing Provenance in Visualization and Data Analysis: An Organizational Framework of Provenance Types and Purposes

    DOE PAGES

    Ragan, Eric; Alex, Endert; Sanyal, Jibonananda; ...

    2016-01-01

    While the primary goal of visual analytics research is to improve the quality of insights and findings, a substantial amount of research in provenance has focused on the history of changes and advances throughout the analysis process. The term, provenance, has been used in a variety of ways to describe different types of records and histories related to visualization. The existing body of provenance research has grown to a point where the consolidation of design knowledge requires cross-referencing a variety of projects and studies spanning multiple domain areas. We present an organizational framework of the different types of provenance informationmore » and purposes for why they are desired in the field of visual analytics. Our organization is intended to serve as a framework to help researchers specify types of provenance and coordinate design knowledge across projects. We also discuss the relationships between these factors and the methods used to capture provenance information. In addition, our organization can be used to guide the selection of evaluation methodology and the comparison of study outcomes in provenance research« less

  10. Geosynthetic clay liners - slope stability field study

    SciTech Connect

    Carson, D.A.; Daniel, D.E.; Koerner, R.M.; Bonaparte, R.

    1997-12-31

    A field research project was developed to examine the internal shear performance of geosynthetic clay liners (GCLs). Several combinations of cross sections were assembled using GCL materials that were available at the time of project initiation. The cross sections utilized were intended to simulate landfill cover applications. Thirteen (13) resulting test plots were constructed on two different slope angles, and each plot is instrumented for physical displacement and soil moisture characteristics. Test plots were constructed in a manner that dictated the shear plane in the clay portion of the GCL product. The project purpose is to assess field performance and to verify design parameters associated with the application of GCLs in waste containment applications. Interim research data shows that test slopes on 2H:1V show global deformation, but little internal shear evidence, and the 3H:1V slopes show little deformation at approximately 650 days. The research is ongoing, and this paper presents the most recent information available from the project.

  11. Naphthene upgrading with pillared synthetic clay catalysts

    SciTech Connect

    Sharma, R.K.; Olson, E.S.

    1995-12-31

    Catalytic hydrotreatment of methylcyclohexane was investigated to model upgrading of coal-derived naphthenes. Nickel-substituted synthetic mica montmorillonite (NiSMM), alumina-pillared NiSMM and Zirconia-pillared NiSMM were prepared and tested for hydrocracking and hydroisomerization of methylcyclohexane. Infrared and thermal desorption studies of the pyridine-adsorbed catalysts indicated the presence of Lewis and Bronsted acid sites. Total acidity and surface area increased with pillaring of NiSMM with polyoxy aluminum and polyoxy zirconium cations. Methylcyclohexane was reacted with these catalysts under a variety of conditions. Pillared clays gave higher gas yields and higher hydrocracking but lower hydroisomerization activity than nonpillared clay. The majority of the products were branched alkanes (isoparaffinic). These catalysts effectively use hydrogen as indicated by the minimal formation of aromatic hydrocarbons, coke, or other oligomeric materials. The effect of various operating conditions, i.e., reaction temperature, contact time, H{sub 2} pressure, and catalyst, on the product distribution will be described.

  12. Rheological study of clay-kaolin aqueous suspensions

    NASA Technical Reports Server (NTRS)

    Lapasin, R.; Lucchini, F.

    1984-01-01

    Rheological characteristics of clay-kaolin aqueous suspensions were studied by a rotational viscometer to correlate their behavior with the properties of ceramic slips for casting containing quartz, feldspars, and other nonplastic materials. In particular, the effects of the different amounts of dry materials and deflocculant (mixture 1:1 of Na2CO3 and Na2SiO3) and of temperatures on the shear-time-dependent properties of suspensions were examined.

  13. Evaluation of Used Fuel Disposition in Clay-Bearing Rock

    SciTech Connect

    Jove-Colon, Carlos F.; Weck, Philippe F.; Hammond, Glenn Edward; Kuhlman, Kristopher L.; Zheng, Liange; Rutqvist, Jonny; Kim, Kunhwi; Houseworth, James; Caporuscio, Florie Andre; Cheshire, Michael; Palaich, Sarah; Norskog, Katherine E.; Zavarin, Mavrik; Wolery, Thomas J.; Jerden, James L.; Copple, Jacqueline M.; Cruse, Terry; Ebert, William L.

    2015-09-04

    -transport and reaction path modeling. The focus of these investigations into the nature of sacrificial zones is to evaluate the chemical effects of heterogeneous chemical reactions at EBS interfaces. The difference in barrier material types and the extent of chemical reactions within these interfacial domains generates changes in mineral abundances. These mineralogical alterations also result in volume changes that, although small, could affect the interface bulk porosity. As in previous deliverables, this report is structured according to various national laboratory contributions describing R&D activities applicable to clay/shale/argillite media.

  14. Kisameet Glacial Clay: an Unexpected Source of Bacterial Diversity.

    PubMed

    Svensson, Sarah L; Behroozian, Shekooh; Xu, Wanjing; Surette, Michael G; Li, Loretta; Davies, Julian

    2017-05-23

    Widespread antibiotic resistance among bacterial pathogens is providing the impetus to explore novel sources of antimicrobial agents. Recently, the potent antibacterial activity of certain clay minerals has stimulated scientific interest in these materials. One such example is Kisameet glacial clay (KC), an antibacterial clay from a deposit on the central coast of British Columbia, Canada. However, our understanding of the active principles of these complex natural substances is incomplete. Like soils, clays may possess complex mixtures of bacterial taxa, including the Actinobacteria, a clade known to be rich in antibiotic-producing organisms. Here, we present the first characterization of both the microbial and geochemical characteristics of a glacial clay deposit. KC harbors surprising bacterial species richness, with at least three distinct community types. We show that the deposit has clines of inorganic elements that can be leached by pH, which may be drivers of community structure. We also note the prevalence of Gallionellaceae in samples recovered near the surface, as well as taxa that include medically or economically important bacteria such as Actinomycetes and Paenibacillus These results provide insight into the microbial taxa that may be the source of KC antibacterial activity and suggest that natural clays may be rich sources of microbial and molecular diversity.IMPORTANCE Identifying and characterizing the resident microbial populations (bacteria, viruses, protozoa, and fungi) is key to understanding the ecology, chemistry, and homeostasis of virtually all sites on Earth. The Kisameet Bay deposit in British Columbia, Canada, holds a novel glacial clay with a history of medicinal use by local indigenous people. We previously showed that it has potent activity against a variety of antibiotic-resistant bacteria, suggesting it could complement our dwindling arsenal of antibiotics. Here, we have characterized the microbiome of this deposit to gain insight

  15. Titian: Data Provenance Support in Spark.

    PubMed

    Interlandi, Matteo; Shah, Kshitij; Tetali, Sai Deep; Gulzar, Muhammad Ali; Yoo, Seunghyun; Kim, Miryung; Millstein, Todd; Condie, Tyson

    2015-11-01

    Debugging data processing logic in Data-Intensive Scalable Computing (DISC) systems is a difficult and time consuming effort. Today's DISC systems offer very little tooling for debugging programs, and as a result programmers spend countless hours collecting evidence (e.g., from log files) and performing trial and error debugging. To aid this effort, we built Titian, a library that enables data provenance-tracking data through transformations-in Apache Spark. Data scientists using the Titian Spark extension will be able to quickly identify the input data at the root cause of a potential bug or outlier result. Titian is built directly into the Spark platform and offers data provenance support at interactive speeds-orders-of-magnitude faster than alternative solutions-while minimally impacting Spark job performance; observed overheads for capturing data lineage rarely exceed 30% above the baseline job execution time.

  16. Provenance and annotation for visual exploration systems.

    PubMed

    Groth, Dennis P; Streefkerk, Kristy

    2006-01-01

    Exploring data using visualization systems has been shown to be an extremely powerful technique. However, one of the challenges with such systems is an inability to completely support the knowledge discovery process. More than simply looking at data, users will make a semipermanent record of their visualizations by printing out a hard copy. Subsequently, users will mark and annotate these static representations, either for dissemination purposes or to augment their personal memory of what was witnessed. In this paper, we present a model for recording the history of user explorations in visualization environments, augmented with the capability for users to annotate their explorations. A prototype system is used to demonstrate how this provenance information can be recalled and shared. The prototype system generates interactive visualizations of the provenance data using a spatio-temporal technique. Beyond the technical details of our model and prototype, results from a controlled experiment that explores how different history mechanisms impact problem solving in visualization environments are presented.

  17. Thermophysical and mechanical characterization of clay bricks reinforced by alfa or straw fibers

    NASA Astrophysics Data System (ADS)

    Elhamdouni, Y.; Khabbazi, A.; Benayad, C.; Mounir, S.; Dadi, A.

    2017-03-01

    This work is part of the valuation of local materials such as clay (earth), alfa fiber and straw fiber. The goal is to use these materials as bricks in rural construction. These materials are abundant, natural, and renewable. The objective of this work is to study the thermal and mechanical behavior of a new material by mixing clay (chosen as the binder) with different mass percentages of alfa fiber (0.5%, 1%, 2%, 3%, 4%), and to compare these results with those of materials often used in the construction of individual houses in rural Morocco (clay + straw). The results obtained prove to us that using straw fibers can reduce the thermal conductivity compared to alfa fiber, which allows to have energy savings of 2% to 7%. By against, alfa fibers can improve the mechanical behavior of clay-based materials when compared to the clay + straw material (an increase of 8% to 17% in the tractive resistance by bending and 6% to 18% for compression resistance). These results also specify the optimal usage conditions of these fibers (alfa and straw) in the clay bricks.

  18. On sorption and swelling of CO2 in clays

    DOE PAGES

    Busch, A.; Bertier, P.; Gensterblum, Y.; ...

    2016-03-23

    One well-studied technology is the geological storage of carbon dioxide (CO2), and a number of demonstration projects around the world have proven its feasibility and challenges. Storage conformance and seal integrity are among the most important aspects, as they determine risk of leakage as well as limits for storage capacity and injectivity. By providing evidence for safe storage is critical for improving public acceptance. Most caprocks are composed of clays as dominant mineral type which can typically be illite, kaolinite, chlorite or smectite. A number of recent studies addressed the interaction between CO2 and these different clays and it wasmore » shown that clay minerals adsorb considerable quantities of CO2. For smectite this uptake can lead to volumetric expansion followed by the generation of swelling pressures. On the one hand CO2 adsorption traps CO2, on the other hand swelling pressures can potentially change local stress regimes and in unfavourable situations shear-type failure is assumed to occur. Moreover, for storage in a reservoir having high clay contents the CO2 uptake can add to storage capacity which is widely underestimated so far. Smectite-rich seals in direct contact with a dry CO2 plume at the interface to the reservoir might dehydrate leading to dehydration cracks. Such dehydration cracks can provide pathways for CO2 ingress and further accelerate dewatering and penetration of the seal by supercritical CO2. At the same time, swelling may also lead to the closure of fractures or the reduction of fracture apertures, thereby improving seal integrity. Finally, the goal of this communication is to theoretically evaluate and discuss these scenarios in greater detail in terms of phenomenological mechanisms, but also in terms of potential risks or benefits for carbon storage.« less

  19. Tracking Monsoon Related Provenance Changes in Continental Margin Sediments of the East China Sea: Preliminary Results from IODP Expedition 346.

    NASA Astrophysics Data System (ADS)

    Anderson, C. H.; Dunlea, A. G.; Murray, R. W.; Kinsley, C. W.; McGee, D.; Giosan, L.; Zheng, H.; Tada, R.; Alvarez Zarikian, C. A.

    2014-12-01

    Sedimentation in the East China Sea (ECS) is driven largely by fluvial and eolian fluxes that are likely influenced by the East Asian Monsoon (EAM). Terrigenous matter from the Yangtze River is transported into the ECS and is also carried by winds of the Westerly Jet. Seasonal and long term shifts in the atmospheric and precipitation regimes over Asia are recorded in the inorganic chemistry of the sediment of the ECS and other Asian coastal seas. For example, changes in intensity and timing of the EAM over short and long term time scales likely impact the relative proportion of fluvial and eolian inputs to the region, and perhaps their individual sources. Bulk sediment was recovered from IODP Sites U1428 and U1429 in the ECS during Expedition 346. T these sites are separated by 7.4 km, located in the northernmost portion of the ECS in the Danjo Basin, and are generally characterized by two sedimentary units. Unit A is largely nannofossil-rich calcareous ooze and calcareous-rich clays, punctuated with smaller tephra layers throughout. Unit B is composed of fine- to medium-grained, rounded sands. Here we present major, trace and rare earth element (REE) data for 54 bulk sediment samples analyzed via ICP-ES and ICP-MS. We trace downhole fluctuations in the geochemical data in order to investigate the provenance of terrigenous material during the Pleistocene. Preliminary major element concentration data indicate the presence of distinct continental sediment and carbonates at both sites. Average downhole major element ratios exhibit limited variation at both sites. For example, Ti/Al (g/g) is tightly constrained with values of 0.05 /- 0.003, Fe/Al 0.5 /- 0.05, and Si/Al 3.3 /- 0.3. In addition to standard geochemical techniques to assess provenance, we are using multivariate statistics (e.g., Q-Mode Factor Analyses, Multiple Linear Regressions) to examine this large dataset. We focus on a smaller suite of elements that are exclusively associated with the terrigenous

  20. Searching for reciclability of modified clays for an environmental application

    NASA Astrophysics Data System (ADS)

    Del Hoyo Martínez, Carmen; Solange Lozano García, Marina; Sánchez Escribano, Vicente; Antequera, Jorge

    2014-05-01

    Thanks to the development of the science and the technology of the nourishment in the last 50 years, there have revealed itself several new substances that can fulfill beneficial functions in the food, and these substances, named food additives, are today within reach of all. The food additives recover a very important role in the complex nourishing supply. The additives fulfill several useful functions in the food, which often we give for sat. Nevertheless the widespread use of food additives in the food production also influences the public health. The food industries, which are very important for the economy, spill residues proved from its activity that they have to be controlled to evaluate the environmental impact and to offer the necessary information about the quantitative evaluation of the chemical risk of the use of food additives for the public health. The clay materials have led to numerous applications in the field of public health (del Hoyo, 2007; Volzone, 2007) having been demonstrated its effectiveness as adsorbents of all contaminants. Some biodegradable materials are used for for adsorption of chemical contaminants: lignins (Valderrabano et al., 2008) and also clays and clay minerals, whose colloidal properties, ease of generating structural changes, abundance in nature, and low cost make them very suitable for this kind of applications. Among the strategies used at present to preserve the quality of the water and this way to diminish the environmental risk that supposes the chemical pollution, stands out the use of adsorbents of under cost, already they are natural or modified, to immobilize these compounds and to avoid the pollution of the water with the consequent reduction of environmental and economic costs. We have studied the adsorption of several contaminants related to the food industry by natural or modified clays, searching their interaction mechanisms and the possible recycling of these materials for environmental purposes and

  1. Clay mineralogy of surface sediments as a tool for deciphering river contributions to the Cariaco Basin (Venezuela)

    NASA Astrophysics Data System (ADS)

    Bout-Roumazeilles, V.; Riboulleau, A.; du Châtelet, E. Armynot; Lorenzoni, L.; Tribovillard, N.; Murray, R. W.; Müller-Karger, F.; Astor, Y. M.

    2013-02-01

    The mineralogical composition of 95 surface sediment samples from the Cariaco Basin continental shelf and Orinoco delta was investigated in order to constrain the clay-mineral main provenance and distribution within the Cariaco Basin. The spatial variability of the data set was studied using a geo-statistical approach that allows drawing representative clay-mineral distribution maps. These maps are used to identify present-day dominant sources for each clay-mineral species in agreement with the geological characteristics of the main river watersheds emptying into the basin. This approach allows (1) identifying the most distinctive clay-mineral species/ratios that determine particle provenance, (2) evaluating the respective contribution of local rivers, and (3) confirming the minimal present-day influence of the Orinoco plume on the Cariaco Basin sedimentation. The Tuy, Unare, and Neveri Rivers are the main sources of clay particles to the Cariaco Basin sedimentation. At present, the Tuy River is the main contributor of illite to the western part of the southern Cariaco Basin continental shelf. The Unare River plume, carrying smectite and kaolinite, has a wide westward propagation, whereas the Neveri River contribution is less extended, providing kaolinite and illite toward the eastern Cariaco Basin. The Manzanares, Araya, Tortuga, and Margarita areas are secondary sources of local influence. These insights shed light on the origin of present-day terrigenous sediments of the Cariaco Basin and help to propose alternative explanations for the temporal variability of clay mineralogy observed in previously published studies.

  2. Natural radionuclides in clay deposits: concentration and dose assessment.

    PubMed

    Khater, Ashraf E M; Al-Mobark, Layla H; Aly, Amany A; Al-Omran, A M

    2013-09-01

    Clays are among the most important industrially used minerals. Three potential clay mineral mining sites in Saudi Arabia were chosen, and 21 clay deposit samples were collected. The activity concentrations (average±standard deviation) of the naturally occurring radioactive materials (NORMs), (238)U, (226)Ra, (232)Th, (228)Ra and (40)K, were 49±20, 47±23, 34±11, 40±20 and 751 Bq kg(-1), respectively. The radiation dose assessments (e.g., absorbed dose rate, nGy h(-1); effective dose equivalent, µSv y(-1); and effective dose rate due to dust inhalation, µSv y(-1)) and hazardous indices (e.g., radium equivalent [Ra-eq] value, external hazardous index [Hex], internal hazardous index [Hin] and representative gamma level [Iγ]) were calculated. The wide variations in the activity concentrations of the NORMs according to sampling region could be due to the origin of the geological formation and the geochemical behaviour of the NORMs. Based on calculated hazardous (external and internal) indices, there were no expected radiological hazardous impacts of using clay deposits as building materials.

  3. Effect of clay distribution in synthetic sand-clay mixtures on hydraulic and geophysical parameters

    NASA Astrophysics Data System (ADS)

    Osterman, G. K.; Keating, K.; Slater, L. D.; Sugand, M.; Binley, A. M.

    2016-12-01

    The hydraulic conductivity of porous geological media is known to be controlled by clay content as well as the distribution of clay. Although numerous studies have explored the effect of clay content on geophysical measurements, most studies of synthetic sediment packs focus on a homogenous distribution of clay particles. In this laboratory experiment, we explore how both clay content and clay distribution impact hydraulic and geophysical parameters. Using two clays—kaolinite and montmorillonite—we prepared homogeneous and heterogeneous sand-clay mixtures containing 0 to 10% clay by mass. To create the heterogeneous mixtures, small (<1 cm diameter) aggregates of the clays were prepared before mixing with sand. The measured geophysical parameters consisted of the spectral induced polarization (SIP) quadrature conductivity and the nuclear magnetic resonance (NMR) mean-log T2 relaxation time, parameters known to be sensitive to changes in pore geometry. Our results show that for the homogenous clay samples, the hydraulic conductivity decreases with increasing clay content, as expected, and both SIP and NMR parameters correlate with the changing hydraulic conductivity. For the aggregated clay samples, there is no correlation between hydraulic conductivity and clay content; however, increasing clay content still impacts the geophysical data. The SIP data are less sensitive to increasing aggregated clay content than the NMR data, which display a similar degree of variability with clay content in mean-log T­2 relaxation time for both homogenous and aggregated clay samples. The results suggest that in heterogeneous clay-bearing sediments, NMR measured parameters are less sensitive to the specific pore geometries controlling fluid flow than the SIP parameters. This research represents a first step towards understanding how the distributions of clay in porous media impacts relationships between geophysical measurements and hydraulic conductivity.

  4. Hyperspectral analysis of clay minerals

    NASA Astrophysics Data System (ADS)

    Janaki Rama Suresh, G.; Sreenivas, K.; Sivasamy, R.

    2014-11-01

    A study was carried out by collecting soil samples from parts of Gwalior and Shivpuri district, Madhya Pradesh in order to assess the dominant clay mineral of these soils using hyperspectral data, as 0.4 to 2.5 μm spectral range provides abundant and unique information about many important earth-surface minerals. Understanding the spectral response along with the soil chemical properties can provide important clues for retrieval of mineralogical soil properties. The soil samples were collected based on stratified random sampling approach and dominant clay minerals were identified through XRD analysis. The absorption feature parameters like depth, width, area and asymmetry of the absorption peaks were derived from spectral profile of soil samples through DISPEC tool. The derived absorption feature parameters were used as inputs for modelling the dominant soil clay mineral present in the unknown samples using Random forest approach which resulted in kappa accuracy of 0.795. Besides, an attempt was made to classify the Hyperion data using Spectral Angle Mapper (SAM) algorithm with an overall accuracy of 68.43 %. Results showed that kaolinite was the dominant mineral present in the soils followed by montmorillonite in the study area.

  5. Material characterization of the clay bonded silicon carbide candle filters and ash formations in the W-APF system after 500 hours of hot gas filtration at AEP. Appendix to Advanced Particle Filter: Technical progress report No. 11, January--March 1993

    SciTech Connect

    Alvin, M.A.

    1993-04-05

    (1) After 500 hours of operation in the pressurized fluidized-bed combustion gas environment, the fibrous outer membrane along the clay bonded silicon carbide Schumacher Dia Schumalith candles remained intact. The fibrous outer membrane did not permit penetration of fines through the filter wall. (2) An approximate 10-15% loss of material strength occurred within the intact candle clay bonded silicon carbide matrix after 500 hours of exposure to the PFBC gas environment. A relatively uniform strength change resulted within the intact candles throughout the vessel (i.e., top to bottom plenums), as well as within the various cluster ring positions (i.e., outer versus inner ring candle filters). A somewhat higher loss of material strength, i.e., 25% was detected in fractured candle segments removed from the W-APF ash hopper. (3) Sulfur which is present in the pressurized fluidized-bed combustion gas system induced phase changes along the surface of the binder which coats the silicon carbide grains in the Schumacher Dia Schumalith candle filter matrix.

  6. Clay content evaluation in soils through GPR signal processing

    NASA Astrophysics Data System (ADS)

    Tosti, Fabio; Patriarca, Claudio; Slob, Evert; Benedetto, Andrea; Lambot, Sébastien

    2013-10-01

    The mechanical behavior of soils is partly affected by their clay content, which arises some important issues in many fields of employment, such as civil and environmental engineering, geology, and agriculture. This work focuses on pavement engineering, although the method applies to other fields of interest. Clay content in bearing courses of road pavement frequently causes damages and defects (e.g., cracks, deformations, and ruts). Therefore, the road safety and operability decreases, directly affecting the increase of expected accidents. In this study, different ground-penetrating radar (GPR) methods and techniques were used to non-destructively investigate the clay content in sub-asphalt compacted soils. Experimental layout provided the use of typical road materials, employed for road bearing courses construction. Three types of soils classified by the American Association of State Highway and Transportation Officials (AASHTO) as A1, A2, and A3 were used and adequately compacted in electrically and hydraulically isolated test boxes. Percentages of bentonite clay were gradually added, ranging from 2% to 25% by weight. Analyses were carried out for each clay content using two different GPR instruments. A pulse radar with ground-coupled antennae at 500 MHz centre frequency and a vector network analyzer spanning the 1-3 GHz frequency range were used. Signals were processed in both time and frequency domains, and the consistency of results was validated by the Rayleigh scattering method, the full-waveform inversion, and the signal picking techniques. Promising results were obtained for the detection of clay content affecting the bearing capacity of sub-asphalt layers.

  7. Clay mineral provinces in tidal mud flats at Germany's North Sea coast with illite K-Ar ages potentially modified by biodegradation

    NASA Astrophysics Data System (ADS)

    Brockamp, Olaf; Clauer, Norbert

    2012-07-01

    Mineralogical studies, chemical analyses and K-Ar dating were carried out on clay fractions from tidal mud flats along the Lower Saxony coast and its bays to identify material sources and sedimentary processes at this dynamic interface between air, land and sea. From the coast into the bays, sediments are enriched in fine-grained smectite relative to the coarser grained illite, chlorite and kaolinite, due to the weakening of the tidal current energy in the bays. In addition, the study area can be divided into two provinces on the basis of the illite K/Rb ratios and Mg contents. To the west [Schiermonnikoog, Dollart, Ley Bay up to Norderney island], longshore currents carry suspensions from the Belgian and Dutch coasts; to the east [from Langeoog island, Jade Bay to the Helgoland mud area] suspensions from the Elbe and Weser rivers are mixed with submarine reworked glacial sediments, whereas the portion of longshore current suspensions from the west decreases, becoming negligible in the Helgoland mud area off the Elbe and Weser estuaries. The illite K-Ar data vary considerably and fail as source indicators due to differential settling and mixing of the clay material and probably to Ar loss from illite by biodegradation during digestive processes. Only further offshore, outside the zone of dynamic sediment dispersion, do the K-Ar data fit provenance patterns.

  8. Sm-Nd dating of Fig Tree clay minerals of the Barberton greenstone belt, South Africa

    NASA Technical Reports Server (NTRS)

    Toulkeridis, T.; Goldstein, S. L.; Clauer, N.; Kroner, A.; Lowe, D. R.

    1994-01-01

    Sm-Nd isotopic data from carbonate-derived clay minerals of the 3.22-3.25 Ga Fig Tree Group, Barberton greenstone belt, South Africa, form a linear array corresponding to an age of 3102 +/- 64 Ma, making these minerals the oldest dated clays on Earth. The obtained age is 120-160 m.y. younger than the depositional age determined by zircon geochronology. Nd model ages for the clays range from approximately 3.39 to 3.44 Ga and almost cover the age variation of the Barberton greenstone belt rocks, consistent with independent evidence that the clay minerals are derived from material of the belt. The combined isotopic and mineralogical data provide evidence for a cryptic thermal overprint in the sediments of the belt. However, the highest temperature reached by the samples since the time of clay-mineral formation was <300 degrees C, lower than virtually any known early Archean supracrustal sequence.

  9. Sm-Nd dating of Fig Tree clay minerals of the Barberton greenstone belt, South Africa

    NASA Technical Reports Server (NTRS)

    Toulkeridis, T.; Goldstein, S. L.; Clauer, N.; Kroner, A.; Lowe, D. R.

    1994-01-01

    Sm-Nd isotopic data from carbonate-derived clay minerals of the 3.22-3.25 Ga Fig Tree Group, Barberton greenstone belt, South Africa, form a linear array corresponding to an age of 3102 +/- 64 Ma, making these minerals the oldest dated clays on Earth. The obtained age is 120-160 m.y. younger than the depositional age determined by zircon geochronology. Nd model ages for the clays range from approximately 3.39 to 3.44 Ga and almost cover the age variation of the Barberton greenstone belt rocks, consistent with independent evidence that the clay minerals are derived from material of the belt. The combined isotopic and mineralogical data provide evidence for a cryptic thermal overprint in the sediments of the belt. However, the highest temperature reached by the samples since the time of clay-mineral formation was <300 degrees C, lower than virtually any known early Archean supracrustal sequence.

  10. Assessment of the Mechanical Properties of Sisal Fiber-Reinforced Silty Clay Using Triaxial Shear Tests

    PubMed Central

    Wu, Yankai; Li, Yanbin; Niu, Bin

    2014-01-01

    Fiber reinforcement is widely used in construction engineering to improve the mechanical properties of soil because it increases the soil's strength and improves the soil's mechanical properties. However, the mechanical properties of fiber-reinforced soils remain controversial. The present study investigated the mechanical properties of silty clay reinforced with discrete, randomly distributed sisal fibers using triaxial shear tests. The sisal fibers were cut to different lengths, randomly mixed with silty clay in varying percentages, and compacted to the maximum dry density at the optimum moisture content. The results indicate that with a fiber length of 10 mm and content of 1.0%, sisal fiber-reinforced silty clay is 20% stronger than nonreinforced silty clay. The fiber-reinforced silty clay exhibited crack fracture and surface shear fracture failure modes, implying that sisal fiber is a good earth reinforcement material with potential applications in civil engineering, dam foundation, roadbed engineering, and ground treatment. PMID:24982951

  11. Assessment of the mechanical properties of sisal fiber-reinforced silty clay using triaxial shear tests.

    PubMed

    Wu, Yankai; Li, Yanbin; Niu, Bin

    2014-01-01

    Fiber reinforcement is widely used in construction engineering to improve the mechanical properties of soil because it increases the soil's strength and improves the soil's mechanical properties. However, the mechanical properties of fiber-reinforced soils remain controversial. The present study investigated the mechanical properties of silty clay reinforced with discrete, randomly distributed sisal fibers using triaxial shear tests. The sisal fibers were cut to different lengths, randomly mixed with silty clay in varying percentages, and compacted to the maximum dry density at the optimum moisture content. The results indicate that with a fiber length of 10 mm and content of 1.0%, sisal fiber-reinforced silty clay is 20% stronger than nonreinforced silty clay. The fiber-reinforced silty clay exhibited crack fracture and surface shear fracture failure modes, implying that sisal fiber is a good earth reinforcement material with potential applications in civil engineering, dam foundation, roadbed engineering, and ground treatment.

  12. Investigations of mechanical and wear properties of alumina/titania/fire-clay reinforced epoxy composites

    NASA Astrophysics Data System (ADS)

    Patel, Vinay Kumar; Chauhan, Shivani; Sharma, Aarushi

    2016-05-01

    In this work, the effect of various particulates (alumina, titania, fire clay) reinforcements on mechanical and wear properties of epoxy composites have been studied with a prime motive of replacing the costly alumina and titania by much economical fire clay for high mechanical strength and/or wear resistant materials. Fire clay based epoxy composites delivered better mechanical (both tensile and impact) properties than the alumina filled or neat epoxy composites and slightly lower than titania reinforced composites, which qualified the fire clay a very suitable cost effective alternatives of both alumina and titania for high mechanical strength based applications. However, the poor wear behavior of fire clay reinforced composites revealed its poor candidacy for wear and tear applications.

  13. Influence of clay minerals on curcumin properties: Stability and singlet oxygen generation

    NASA Astrophysics Data System (ADS)

    Gonçalves, Joyce L. S.; Valandro, Silvano R.; Poli, Alessandra L.; Schmitt, Carla C.

    2017-09-01

    Curcumin (CUR) has showed promising photophysical properties regarding to biological and chemical sciences. However, the main barrier for those applications are their low solubility and stability in aqueous solution. The effects of two different clay minerals, the montmorillonite (SWy-2) and the Laponite RD (Lap) nanoclay, on the stabilization of Curcumin were investigated. Their effects were compared with two well-established environments (acidic and neutral aqueous media). CUR/clay hybrids were prepared using a simple and fast method, where CUR solution was added into clay suspensions, to obtain well dispersed hybrids in water. The degradation process of CUR and CUR/clays hybrids was investigated using UV-Vis spectroscopic. For both studied hybrids, the CUR degradation process was suppressed by the presence of the clay particles. Furthermore, the Lap showed a great stabilization effect than SWy-2. This behavior was due to the smaller particle size and higher exfoliation ability of Lap, providing a large surface for CUR adsorption compared to SWy-2. The degradation process of CUR solutions and CUR/clay hybrids was also studied in the presence of light. CUR photodegradation process was faster not only in the aqueous solution but also in the clay suspension compared to those studied in the dark. The presence of clay particles accelerated the photodegradation of CUR due to the products formation in the reactions between CUR and oxygen radicals. Our results showed that the singlet oxygen quantum yield (ΦΔ) of CUR were about 59% higher in the clay suspensions than CUR in aqueous solution. Therefore, the formation of CUR/clay hybrids, in particularly with Lap, suppressed the degradation in absence light of CUR and increased the singlet oxygen generation, which makes this hybrids of CUR/clay a promising material to enlarge the application of CUR in the biological sciences.

  14. Prolonged triboluminescence in clays and other minerals

    NASA Technical Reports Server (NTRS)

    Lahav, N.; Coyne, L. M.; Lawless, J. G.

    1982-01-01

    Samples of various clays and minerals were ground or fractured and monitored with a liquid scintillation spectrometer in order to obtain triboluminescent decay curves. Kaolinite samples displayed several million counts/min after grinding, with a surface area emission estimated at tens of billions of photons/sq cm of surface. The photon production rates varied with the origin of the sample, and kaolinite continually yielded higher production rates than bentonite. The addition of water to the samples slightly increased the count rate of emitted light, while the addition of the fluorescent molecule substance tryptofan significantly enhanced the count rate. Freezing smears of kaolinite and montmorillonite in liquid nitrogen and in a salt ice mixture also induced triboluminescence in the montmorillonite. A possible connection between powdery triboluminescent materials formed in mining industries and respiratory disorders among miners is suggested.

  15. Cytocompatibility and uptake of halloysite clay nanotubes.

    PubMed

    Vergaro, Viviana; Abdullayev, Elshad; Lvov, Yuri M; Zeitoun, Andre; Cingolani, Roberto; Rinaldi, Ross; Leporatti, Stefano

    2010-03-08

    Halloysite is aluminosilicate clay with hollow tubular structure of 50 nm external diameter and 15 nm diameter lumen. Halloysite biocompatibility study is important for its potential applications in polymer composites, bone implants, controlled drug delivery, and for protective coating (e.g., anticorrosion or antimolding). Halloysite nanotubes were added to different cell cultures for toxicity tests. Its fluorescence functionalization by aminopropyltriethosilane (APTES) and with fluorescently labeled polyelectrolyte layers allowed following halloysite uptake by the cells with confocal laser scanning microscopy (CLSM). Quantitative Trypan blue and MTT measurements performed with two neoplastic cell lines model systems as a function of the nanotubes concentration and incubation time indicate that halloysite exhibits a high level of biocompatibility and very low cytotoxicity, rendering it a good candidate for household materials and medicine. A combination of transmission electron microscopy (TEM), scanning electron microscopy (SEM), and scanning force microscopy (SFM) imaging techniques have been employed to elucidate the structure of halloysite nanotubes.

  16. Prolonged triboluminescence in clays and other minerals

    NASA Technical Reports Server (NTRS)

    Lahav, N.; Coyne, L. M.; Lawless, J. G.

    1982-01-01

    Samples of various clays and minerals were ground or fractured and monitored with a liquid scintillation spectrometer in order to obtain triboluminescent decay curves. Kaolinite samples displayed several million counts/min after grinding, with a surface area emission estimated at tens of billions of photons/sq cm of surface. The photon production rates varied with the origin of the sample, and kaolinite continually yielded higher production rates than bentonite. The addition of water to the samples slightly increased the count rate of emitted light, while the addition of the fluorescent molecule substance tryptofan significantly enhanced the count rate. Freezing smears of kaolinite and montmorillonite in liquid nitrogen and in a salt ice mixture also induced triboluminescence in the montmorillonite. A possible connection between powdery triboluminescent materials formed in mining industries and respiratory disorders among miners is suggested.

  17. Adsorption of hydrocarbons on organo-clays--implications for oil spill remediation.

    PubMed

    Carmody, Onuma; Frost, Ray; Xi, Yunfei; Kokot, Serge

    2007-01-01

    Organo-clays synthesised by the ion exchange of sodium in Wyoming Na-montmorillonite (SWy-2-MMT) with three surfactants: (a) octadecyltrimethylammonium bromide (ODTMA), formula C(21)H(46)NBr; (b) dodecyldimethylammonium bromide (DDDMA), formula C(22)H(48)BrN; and (c) di(hydrogenated tallow)dimethylammonium chloride were tested for hydrocarbon adsorption. Using diesel, hydraulic oil, and engine oil an evaluation was made of the effectiveness of the sorbent materials for a range of hydrocarbon products that are likely to be involved in land-based oil spills. It was found that the hydrocarbon sorption capacity of the organo-clays depended upon the materials and surfactants used in the organo-clay synthesis. Greater adsorption was obtained if the surfactant contained two or more hydrocarbon long chains. Extensive utilisation of chemometrics principally with the aid of MCDM methods, produced models which consistently ranked the organo-clays well above any of the competitors including commercial benchmark materials. Thus, the use of organo-clays for cleaning up oil spills is feasible due to its many desirable properties such as high hydrocarbon sorption and retention capacities, hydrophobicity. The negative effects of the use of organo-clays for oil-spill cleanup are the cost, the biodegradability, and recyclability of the organo-clays.

  18. MRI profiles over very wide concentration ranges: application to swelling of a bentonite clay.

    PubMed

    Dvinskikh, S V; Szutkowski, K; Furó, I

    2009-06-01

    In MRI investigation of soils, clays, and rocks, mainly mobile water is detected, similarly to that in biological and medical samples. However, the spin relaxation properties of water in these materials and/or low water concentration may make it difficult to use standard MRI approaches. Despite these limitations, one can combine MRI techniques developed for solid and liquid states and use independent information on relaxation properties of water, interacting with the material of interest, to obtain true images of both water and material content. We present procedures for obtaining such true density maps and demonstrate their use for studying the swelling of bentonite clay by water. A constant time imaging protocol provides 1D mapping of the clay distribution in regions with clay concentration above 10 vol%. T(1) relaxation time imaging is employed to monitor the clay content down to 10(-3) vol%. Data provided by those two approaches are in good agreement in the overlapping range of concentrations. Covering five orders of magnitude of clay concentration, swelling of sodium-exchanged bentonite clays from pre-compacted pellets into a gel phase is followed in detail.

  19. MRI profiles over very wide concentration ranges: Application to swelling of a bentonite clay

    NASA Astrophysics Data System (ADS)

    Dvinskikh, S. V.; Szutkowski, K.; Furó, I.

    2009-06-01

    In MRI investigation of soils, clays, and rocks, mainly mobile water is detected, similarly to that in biological and medical samples. However, the spin relaxation properties of water in these materials and/or low water concentration may make it difficult to use standard MRI approaches. Despite these limitations, one can combine MRI techniques developed for solid and liquid states and use independent information on relaxation properties of water, interacting with the material of interest, to obtain true images of both water and material content. We present procedures for obtaining such true density maps and demonstrate their use for studying the swelling of bentonite clay by water. A constant time imaging protocol provides 1D mapping of the clay distribution in regions with clay concentration above 10 vol%. T1 relaxation time imaging is employed to monitor the clay content down to 10 -3 vol%. Data provided by those two approaches are in good agreement in the overlapping range of concentrations. Covering five orders of magnitude of clay concentration, swelling of sodium-exchanged bentonite clays from pre-compacted pellets into a gel phase is followed in detail.

  20. Modernity and putty-clay

    NASA Astrophysics Data System (ADS)

    Ganesh, Trichur Kailas

    This dissertation addresses issues arising out of the problems of capital accumulation, productivity growth and 'putty-clay' technology. The concept of economic modernity occupies a central place in the subject-matter studied here in that it expresses both the incessant drive for newness that characterizes economic reality and the persistence of dated techniques that successfully resist replacement. This study examines the way in which an expansive development-theoretic 'putty-clay' framework may be employed to explain the historical processes behind both the avalanche of newness (innovations) and the conservatism of technology in the U.S. economy. The guiding link is the fixity of investments in physical capital equipment over time and space. The dilemma of fixed capital is studied in the context of the constant entrepreneurial search for flexibility and liquidity. The thesis advanced is that a development (Entwicklung)-theoretic 'putty-clay' conceptualization of the economic system adequately addresses the recurring problems of fixity, flexibility, and liquidity, and thereby permits important insights into the enigma surrounding the persistent productivity growth slowdown and 'stagflation' of the late sixties and seventies and the related phenomena of physical 'capital obsolescence' and the financial or 'speculative explosions' of our times. The notion of 'putty-clay' used here is an innovative one in that it departs from the growth-theoretic literature to re-appear as a Schumpeterian theory of modernity modified by a Veblenite view of an economic system directed by the exigencies of the 'machine-process'. The empirical aptitude of a macroeconomic 'putty-clay' model to explain capital obsolescence mediated by the energy 'crises' (supply shocks) of the seventies and eighties is examined in a separate chapter with results that differ markedly from the standard (Berndt and Wood) conclusions for the U.S. economy. The final chapter in the dissertation reverts to the

  1. Delineation of a quick clay zone at Smørgrav, Norway, with electromagnetic methods under geotechnical constraints

    NASA Astrophysics Data System (ADS)

    Kalscheuer, Thomas; Bastani, Mehrdad; Donohue, Shane; Persson, Lena; Aspmo Pfaffhuber, Andreas; Reiser, Fabienne; Ren, Zhengyong

    2013-05-01

    In many coastal areas of North America and Scandinavia, post-glacial clay sediments have emerged above sea level due to iso-static uplift. These clays are often destabilised by fresh water leaching and transformed to so-called quick clays as at the investigated area at Smørgrav, Norway. Slight mechanical disturbances of these materials may trigger landslides. Since the leaching increases the electrical resistivity of quick clay as compared to normal marine clay, the application of electromagnetic (EM) methods is of particular interest in the study of quick clay structures. For the first time, single and joint inversions of direct-current resistivity (DCR), radiomagnetotelluric (RMT) and controlled-source audiomagnetotelluric (CSAMT) data were applied to delineate a zone of quick clay. The resulting 2-D models of electrical resistivity correlate excellently with previously published data from a ground conductivity metre and resistivity logs from two resistivity cone penetration tests (RCPT) into marine clay and quick clay. The RCPT log into the central part of the quick clay identifies the electrical resistivity of the quick clay structure to lie between 10 and 80 Ω m. In combination with the 2-D inversion models, it becomes possible to delineate the vertical and horizontal extent of the quick clay zone. As compared to the inversions of single data sets, the joint inversion model exhibits sharper resistivity contrasts and its resistivity values are more characteristic of the expected geology. In our preferred joint inversion model, there is a clear demarcation between dry soil, marine clay, quick clay and bedrock, which consists of alum shale and limestone.

  2. Clay mineral particles as effficient carriers of methylene blue used for antimicrobial treatment.

    PubMed

    Bujdák, Juraj; Jureceková, Jana; Bujdákova, Helena; Lang, Kamil; Sersen, Frantisek

    2009-08-15

    There is a strong demand to identify new strategies for disinfection and treatment of human, animal, and plant pathogens. The presented work shows the potential of clay minerals to contribute to the development of novel disinfection materials. Enhanced antimicrobial effect of a photoactive organic dye, methylene blue (MB), in the colloids of clay mineral was observed. Singlet oxygen (1O2) formed upon visible light irradiation was detected directly using luminescence measurements atthe near-infrared region and by spin-trapping method. While MB adsorbed on clay colloid particles lost the ability to produce 1O2 due to molecular aggregation, surprisingly, the antimicrobial activity was significantly enhanced. Under visible light irradiation, MB/clay minerals dispersions prevented the sporulation of A. niger and Penicillium sp. and inhibited the growth of C. albicans by an additional 6-15% when compared with MB solution. In the experiments with E. coli, the efficiency of MB was increased by the reduction of surviving cells by 27 and 33%. S. aureus proved to be the most susceptible to MB/clay dispersions. Only less than 20% cells survived with respect to the control experiment at the low MB concentration (1.1 x 10(-6) mol dm(-3)). The contradiction between the significant antimicrobial properties of MB in clay colloidal systems and low 1O2 formation can be explained in terms of the photosensitization mechanism. The role of clay particles is most likely to promote the contact between microorganism cells and photoactive MB. Although the dye directly bound to the clay surface exhibits significantly reduced photoactivity, the presence of clay mediates the delivery of dye molecules on the surface or inside cells. The results indicate new perspectives of potential implementations of clay minerals as parts of complex disinfection materials for industrial applications or in understanding similar processes in nature.

  3. Sorption-desorption behavior of PCP on soil organic matter and clay minerals.

    PubMed

    Pu, Xunchi; Cutright, Teresa J

    2006-08-01

    Pentachlorophenol (PCP) contamination is a severe environmental problem due to its widespread occurrence, toxicity and recalcitrance. In order to gain a better understanding of the fate of PCP in soils, the role of the soil organic matter (SOM) and clay minerals in the PCP sorption-desorption was studied on two bulk field soils, two subsoils (i.e., SOM or clay-removed soil) and two artificial soils. The two field soils used were a silty loam from New Mexico (NM) containing 10% clay and a sandy-clay-loam from Colombia (CO) South America comprised of 18% clay minerals. The bulk CO soil containing kaolinite sorbed significantly less PCP than the NM soil. All soils depicted an apparent hysteresis during sorption. The CO bulk and subsoils desorbed 14-20% and 15-26% of the sorbed PCP respectively whereas the NM bulk and subsoils desorbed only 4-12% and 5-16%, respectively. Experiments conducted with pure clay and artificial soils indicated that the expandable clay minerals were key sorbent material. Additional studies to investigate the interaction between SOM and clay minerals are needed to fully understand sorptive phenomena.

  4. Comparative study of illite clay and illite-based geopolymer products

    NASA Astrophysics Data System (ADS)

    Sperberga, I.; Sedmale, G.; Stinkulis, G.; Zeila, K.; Ulme, D.

    2011-10-01

    Quaternary (Q-clay) clayey deposits are one of the dominating parts of mineral raw materials of the sedimentary cover at present area of Latvia. These clays can be characterised by illite content up to 75-80 %. Two ways for use of illite clays were studied: conventional and geopolymers method. Purpose of the second mentioned method was showing the influence of alkali (KOH) on the transformation of Q-clay/illite structure. Obtained products were investigated by IR-spectroscopy, DTA and XRD, pore size distribution was determined as well. Some ceramic properties and compressive strength were determined and compared. IR-spectrum showed the effect of alkali on the transformation of Q-clay/illite structure in three main absorption bands: 3620-3415 cm-1 which is related to the vibrational modes of adsorbed water between SiO4 and AlO6 layers; new stronger absorption bands at 1635 cm-1 and 1435 cm-1 indicate on the appearance of vibrations in Q-KOH and are related to the K-O-Si bonds; the most essential changes are vibrations at 850 cm-1 showing the changes in the coordination number of Al from 6 to 4 for Q-KOH. Investigations of the bulk density in dependence on temperature showed the small increase of bulk density for Q-clay while - the relatively remarkable decrease for Q-clay/KOH. Mentioned values correlate with the compressive strength of Q-clay and Q-KOH products.

  5. The Mobility of Organic Contaminants in Water and Clays

    NASA Astrophysics Data System (ADS)

    Lock, P. A.; Skipper, N. T.; Mirza, Z.; Fernandez-Alonso, F.; Adams, M.; Howells, S.; Swenson, J.

    2005-12-01

    The interlayer pores of swelling clays provide an ideal environment in which to study confined fluids, and are the site of many important hydrological and petrological processes. Swelling clays, such as vermiculites, are layered minerals, widespread in soils and sedimentary rocks and are an important sink/source of many toxic organic chemicals. Knowledge of diffusion of organics through clay-rich materials is therefore highly relevant to environmental issues. Experimental studies of solvation structure in aqueous systems show that charged groups can co-ordinate the surrounding water molecules quite strongly, but their is less certainty about the effect of polar and apolar groups. There is currently interest in bulk water-alcohol systems since these are known to aggregate at the nanometer scale. Our hypothesis is that the property of the interlayer fluids in clays arises from the very subtle balance of forces between the interactions of water, cations, clay and organic species. Quasi Elastic Neutron Scattering (QENS) has been used to probe the dynamics of fluids trapped inside clays and reveal the first detailed picture of confined methanol, phenol and glycol in aqueous solution. The picture that emerges is that these model contaminant molecules are surprisingly mobile. Successive QENS broadening for methanol in Na-Vermiculite over 150-330K was measured. The progressive broadening of the energy signal was accompanied by decrease in amplitude with rise in temperature. This is indicative of an overall increase in rotational and translational freedom. Methanol exhibits a Fickian diffusion mechanism as an unconfined fluid, characterised by a linear dependence of broadening of the energy signal with the scattering vector. Inside Na-Vermiculite clay however, the same fluid produces a signal broadening that becomes non-linear indicating a jump activated motion to be present. Glycol and phenol are also of fundamental interest, the former as a clay-swelling inhibitor of

  6. EFFECTS OF COLD STRATIFICATION AND GA3 ON GERMINATION OF ARBUTUS UNEDO SEEDS OF THREE PROVENANCES

    PubMed Central

    Pipinis, Elias; Stampoulidis, Athanasios; Milios, Elias; Kitikidou, Kyriaki; Radoglou, Kalliopi

    2017-01-01

    Background: Arbutus unedo is a valuable Mediterranean shrub as an ornamental plant as well as fruit tree. Fresh fruits of A. unedo are a good source of antioxidants, of vitamins C, E and carotenoids and also are characterized by the high content of mineral elements. Materials and Methods: The effects of gibberellic acid (GA3) and cold stratification (CS) on seed germination performance were investigated in A. unedo seeds collected from three provenances in the Northern part of Greece. Seeds of each provenance were soaked in solutions of GA3 (500, 1000 or 2000 ppm) for 24 h and subsequently were subjected to CS at 3 - 5°C for 0, 1, 2, and 3 months. Results: Non-stratified seeds of the three A. unedo provenances which were not treated with GA3 solutions exhibited very low germination. However, seed germination was significantly improved after a one-month period of CS. Similarly, the non-stratified seeds of all three provenances became non-dormant after the treatment with 2000 ppm GA3 and they germinated at high percentages. However, in untreated seeds with GA3, after a one-month CS period the seeds of the Pieria provenance exhibited higher germination percentage than that of Rodopi provenance seeds. Furthermore, in non-stratified seeds, the Pieria provenance seeds treated with GA3 germinated at higher percentages and more rapidly than those of the other two provenances. Conclusion: The results indicated that untreated seeds exhibited very low germination at 20/25°C. However, in all three provenances seed germinability was significantly improved by a one-month period of CS or treatment of seeds with 2000 ppm GA3. Furthermore, there was a considerable variability among seed provenances in response to the treatments which were applied. PMID:28480410

  7. Magnetic resonance imaging of clays: swelling, sedimentation, dissolution

    NASA Astrophysics Data System (ADS)

    Dvinskikh, Sergey; Furo, Istvan

    2010-05-01

    While most magnetic resonance imaging (MRI) applications concern medical research, there is a rapidly increasing number of MRI studies in the field of environmental science and technology. In this presentation, MRI will be introduced from the latter perspective. While many processes in these areas are similar to those addressed in medical applications of MRI, parameters and experimental implementations are often quite different and, in many respects, far more demanding. This hinders direct transfer of existing methods developed for biomedical research, especially when facing the challenging task of obtaining spatially resolved quantitative information. In MRI investigation of soils, clays, and rocks, mainly water signal is detected, similarly to MRI of biological and medical samples. However, a strong variation of water mobility and a wide spread of water spin relaxation properties in these materials make it difficult to use standard MRI approaches. Other significant limitations can be identified as following: T2 relaxation and probe dead time effects; molecular diffusion artifacts; varying dielectric losses and induced currents in conductive samples; limited dynamic range; blurring artifacts accompanying drive for increasing sensitivity and/or imaging speed. Despite these limitations, by combining MRI techniques developed for solid and liquid states and using independent information on relaxation properties of water, interacting with the material of interest, true images of distributions of both water, material and molecular properties in a wide range of concentrations can be obtained. Examples of MRI application will be given in the areas of soil and mineral research where understanding water transport and erosion processes is one of the key challenges. Efforts in developing and adapting MRI approaches to study these kinds of systems will be outlined as well. Extensive studies of clay/water interaction have been carried out in order to provide a quantitative

  8. Identification and characterization of hydrothermally altered zones in granite by combining synthetic clay content logs with magnetic mineralogical investigations of drilled rock cuttings

    NASA Astrophysics Data System (ADS)

    Meller, Carola; Kontny, Agnes; Kohl, Thomas

    2014-10-01

    Clay minerals as products of hydrothermal alteration significantly influence the hydraulic and mechanical properties of crystalline rock. Therefore, the localization and characterization of alteration zones by downhole measurements is a great challenge for the development of geothermal reservoirs. The magnetite bearing granite of the geothermal site in Soultz-sous-Forêts (France) experienced hydrothermal alteration during several tectonic events and clay mineral formation is especially observed in alteration halos around fracture zones. During the formation of clay minerals, magnetite was oxidized into hematite, which significantly reduces the magnetic susceptibility of the granite from ferrimagnetic to mostly paramagnetic values. The aim of this study was to find out if there exists a correlation between synthetic clay content logs (SCCLs) and measurements of magnetic susceptibility on cuttings in the granite in order to characterize their alteration mineralogy. Such a correlation has been proven for core samples of the EPS1 reference well. SCCLs were created from gamma ray and fracture density logs using a neural network. These logs can localize altered fracture zones in the GPK1-4 wells, where no core material is available. Mass susceptibility from 261 cutting samples of the wells GPK1-GPK4 was compared with the neural network derived synthetic logs. We applied a combination of temperature dependent magnetic susceptibility measurements with optical and electron microscopy, and energy dispersive X-ray spectroscopy to discriminate different stages of alteration. We found, that also in the granite cuttings an increasing alteration grade is characterized by an advancing oxidation of magnetite into hematite and a reduction of magnetic susceptibility. A challenge to face for the interpretation of magnetic susceptibility data from cuttings material is that extreme alteration grades can also display increased susceptibilities due to the formation of secondary magnetite

  9. Role And Behaviour Of Clay Minerals In Alpine Debris Flows

    NASA Astrophysics Data System (ADS)

    Boivin, P.; Bardou, E.; Pfeiffer, H.

    2004-12-01

    The role of clay minerals is generally considered as negligible in alpine debris flow studies and experiments. This assumption is discussed on the basis of field and experimental data. In two neighbouring alpine catchments, with similar morphology and contrasted geology, the physical, mineralogical and chemical properties of the fine earth (<2mm fraction) of soils, debris flow deposits, and parent materials were compared. The clay minerals (clay and silt size) were extracted and characterized for mineralogy and cation exchange capacity (CEC). Their critical coagulation concentrations (CCC) were determined in laboratory experiments. The soil and surface solutions were sampled and monitored for chemical composition, which were compared to the experimental CCCs. The chemical equilibration time between soil solution and solid phase was tested on saturated paste extracts. It was observed that the fine earth of the debris flow deposits was not representative of the triggering materials in terms of fabric, density, particle size, particle shape and mineralogy. Results show that the particles were rounded, crushed and segregated during the flow. The parent materials were composed of platy particles with a small bulk density suggesting an edge-to edge fabric. It contained phyllosilicates of silt and clay size, coated with transformed organic matter. The deposits were composed of rounded particles with a large bulk density suggesting a close-packed fabric. Compared to the parent materials, the deposits contained a larger amount of large mono-crystalline particles of either quartz or calcite with round shape, and less small platy particles of phyllosilicates. The CEC of the fine earth and of the clay-size and silt-size particles was consequently about two times higher in the parent materials than in the deposits. This was interpreted as the results of two main phenomena, namely (i) the leaching of the suspended colloidal particles out of the deposits during the depositional

  10. Actualistic Ophiolite Provenance: The Cyprus Case.

    PubMed

    Garzanti; Andò; Scutellà

    2000-03-01

    The island of Cyprus represents an excellent site to assess quantitatively petrologic clastic response to actively obducting oceanic sources in order to define an actualistic reference for ophiolite provenance, in terms of framework composition and heavy mineral suites. An improved methodology, an extension of the classic ternary QFL logic to include a wider spectrum of key indexes and ratios, provides an accurate synthesis of modal data and allows differentiation of three main petrographic provinces and at least seven subprovinces. Diagnostic signatures of detritus from various levels of an oceanic lithospheric source, and criteria for distinguishing provenance from suprasubduction versus mid-oceanic ophiolites are also outlined. Modern sands derived from the Troodos Ophiolite contain variable proportions of largely pelagic carbonate to chert, boninite to basalt, diabase to metabasite, plagiogranite to gabbroic, and cumulate grains supplied from progressively deeper-seated levels of the multilayered oceanic crust. Dense minerals are mainly clinopyroxenes (diopside), prevailing over orthopyroxenes (enstatite, hypersthene, clinoenstatite), hornblende, tremolite/actinolite, and epidote. Where serpentinized mantle harzburgites have been unroofed, detritus is markedly enriched in cellular serpentinite grains and enstatite, with still negligible olivine and spinel. Sedimentaclastic sands dominated by chert (Mamonia Province) or carbonate grains (Kyrenia Province) are deposited along the southern and northern shores of the island, respectively. Compositions of Cyprus sands are virtually unaffected by climatic, sedimentary, or anthropic processes; recycling of sandstones from foreign sources is a major process only in the Karpaz Peninsula. Petrographic analysis also provides an independent mean to identify prevalent directions of longshore sand transport.

  11. Data Provenance in Photogrammetry Through Documentation Protocols

    NASA Astrophysics Data System (ADS)

    Carboni, N.; Bruseker, G.; Guillem, A.; Bellido Castañeda, D.; Coughenour, C.; Domajnko, M.; de Kramer, M.; Ramos Calles, M. M.; Stathopoulou, E. K.; Suma, R.

    2016-06-01

    Documenting the relevant aspects in digitisation processes such as photogrammetry in order to provide a robust provenance for their products continues to present a challenge. The creation of a product that can be re-used scientifically requires a framework for consistent, standardised documentation of the entire digitisation pipeline. This article provides an analysis of the problems inherent to such goals and presents a series of protocols to document the various steps of a photogrammetric workflow. We propose this pipeline, with descriptors to track all phases of digital product creation in order to assure data provenance and enable the validation of the operations from an analytic and production perspective. The approach aims to support adopters of the workflow to define procedures with a long term perspective. The conceptual schema we present is founded on an analysis of information and actor exchanges in the digitisation process. The metadata were defined through the synthesis of previous proposals in this area and were tested on a case study. We performed the digitisation of a set of cultural heritage artefacts from an Iron Age burial in Ilmendorf, Germany. The objects were captured and processed using different techniques, including a comparison of different imaging tools and algorithms. This augmented the complexity of the process allowing us to test the flexibility of the schema for documenting complex scenarios. Although we have only presented a photogrammetry digitisation scenario, we claim that our schema is easily applicable to a multitude of 3D documentation processes.

  12. RAPD profile variation amongst provenances of neem.

    PubMed

    Farooqui, N; Ranade, S A; Sane, P V

    1998-08-01

    Neem, described as a tree for solving global problems, is an evergreen, long-lived, multipurpose tree of the tropics with a wide distribution range in India. It is believed to be highly cross-pollinated. Inter-provenance variations have been reported in neem in case of morphological and physiological characters. Yet no reports about the genetic determinism for these variations are available to our knowledge. In order to have an idea about the extent and/or nature of genetic (DNA) variation in neem, the powerful RAPD technique has been employed. RAPD profiles of 34 accessions/provenances of neem were generated with 200 decamer random primers, of which the data from the 49 primers, that resulted in reproducible amplification products, were considered for analysis. Based on the presence/absence of bands, a similarity matrix was computed. Dendrogram was constructed by UPGMA method based on the pairwise similarities amongst the RAPD profiles. The similarities in RAPD profiles amongst the different DNAs was more than that expected due to the cross-pollinated nature of the tree and furthermore, these more-than-expected similarities were not due to random chance. These results suggest that neem may have a narrow genetic base.

  13. Provenance of sediments from Sumatra, Indonesia

    NASA Astrophysics Data System (ADS)

    Liebermann, Christof; Hall, Robert; Gough, Amy

    2017-04-01

    The island of Sumatra is situated at the south-western margin of the Indonesian archipelago. Sumatra is affected by active continental margin volcanism along the Sunda Trench, west of Sumatra as a result of active northeast subduction of the Indian plate under the Eurasian plate. Exposures of the Palaeozoic meta-sedimentary basement are mainly limited in extent to the northeast-southwest trending Barisan Mountain chain. The younger Cenozoic rocks are widespread across Sumatra, but can be grouped into structurally subdivided 'fore-arc', 'intramontane', and 'back-arc' basins. However, the formation of the basins pre-dates the current magmatic arc, thus a classical arc-related generation model can not be applied. The Cenozoic formations are well studied due to hydrocarbon enrichment, but little is known about their provenance history. A comprehensive sedimentary provenance study of the Cenozoic formations can aid in the wider understanding of Sumatran petroleum plays, can contribute to palaeographic reconstruction of western SE Asia, and might help to simplify the overall stratigraphy of Sumatra. This work represents a multi-proxy provenance study of sedimentary rocks from the main Cenozoic basins of Sumatra, alongside sediment from present-day river systems. The project refines the provenance in two ways: first, by studying the heavy mineral assemblages of the targeted formations, and secondly, by U-Pb detrital zircon dating using LA-ICP-MS to identify the age-range of the potential sediment sources. Preliminary U-Pb zircon age-data of >1500 concordant grains (10% discordant cut-off), heavy mineral compositions, and thin section analysis from two fieldwork seasons indicate a mixed provenance model, with a proximal igneous source, and mature basement rocks. An increase of the proximal signature in Lower-Miocene strata indicated by the occurrence of unstable heavy mineral phases such as apatite, and clinopyroxene suggests a major change of the source at the Oligocene

  14. The Open Provenance Model core specification (v1.1)

    SciTech Connect

    Moreau, Luc; Clifford, Ben; Freire, Juliana; Futrelle, Joe; Gil, Yolanda; Groth, Paul; Kwasnikowska, Natalia; Miles, Simon; Missier, Paolo; Myers, Jim; Plale, Beth; Simmhan, Yogesh; Stephan, Eric; den Bussche, Jan Van

    2011-06-01

    The Open Provenance Model is a model of provenance that is designed to meet the following requirements: (1) To allow provenance information to be ex- changed between systems, by means of a compatibility layer based on a shared provenance model. (2) To allow developers to build and share tools that operate on such a provenance model. (3) To deFIne provenance in a precise, technology- agnostic manner. (4) To support a digital representation of provenance for any “thing, whether produced by computer systems or not. (5) To allow multiple levels of description to coexist. (6) To deFIne a core set of rules that identify the valid inferences that can be made on provenance representation. This docu- ment contains the speciFIcation of the Open Provenance Model (v1.1) resulting from a commChallenge.

  15. Modelling iron clay interactions in deep geological disposal conditions

    NASA Astrophysics Data System (ADS)

    Bildstein, O.; Trotignon, L.; Perronnet, M.; Jullien, M.

    In the context of deep geological disposal of high level radioactive wastes, the interactions between iron and clay-rich materials may lead to adverse transformations of clay minerals with a potential loss of confining properties such as swelling and capacity to exchange cations. Such transformations have been experimentally observed at temperatures starting at ca. 80 °C, where smectites contained in a mixture of bentonite and iron powder are transformed into iron-rich serpentine-type minerals. The reaction-transport code CRUNCH is used to investigate the iron-clay interactions at 50 °C over a period of 10,000 years, which are the conditions considered here to represent the mean temperature value and the expected timescale for the corrosion stage. The aim is to predict the nature and quantity of corrosion product, calculate the chemistry of water (essentially the pH) and the mineralogical transformation in the system containing the canister, an optional engineered barrier (bentonite) and the host-rock (argillite). The results of the calculations show that at the interface with the canister, where steel corrosion occurs, the iron is partly immobilized by the precipitation of iron oxides (essentially magnetite) and small amounts of siderite. The pH stabilizes at high values, between 10 and 11, at this location. In the bentonite or the argillite in contact with the container, the primary clay minerals are destabilized and iron-rich serpentine-like minerals precipitate as observed in the experiments (cronstedtite and berthierine). These minerals show low cation exchange and swelling capacities. The results also show that the interactions between iron and clay may lead to significant porosity changes in the system. A reduction of the porosity is predicted at the surface of the steel canister, due to the precipitation of iron oxides. Porosity increase is predicted in the clay material due to the dissolution of the primary clay minerals. The effect of these porosity

  16. Mineralogy and thermal properties of clay from Slatina (Ub, Serbia)

    NASA Astrophysics Data System (ADS)

    Milosevic, Maja; Logar, Mihovil; Kaludjerovic, Lazar; Jelic, Ivana

    2017-04-01

    The "Slatina" deposit, Ub, Serbia was opened in 1965 and represents one of few deposits exploited by "Kopovi" a.d., Ub, company. Deposit is composed of clay layers belonging to Neogene sediments that are widespread transgressive over granitoid rocks of Cer mountain and Paleozoic and Mesozoic sediments. Clay is mostly of illite-montmorillonite-kaolinite type and they are generally used as ceramic materials while some of the layers are used as fire-resistant materials. In this study we present mineralogical and thermal characterization of two samples to determine their application as industrial materials. Chemical and mineral composition was determined using inductively coupled plasma optical emission spectroscopy (ICP-OES), X-ray diffraction (XRD) on powder and oriented samples, infrared spectroscopy (IR) and granulometry. Cationic exchange capacity (CEC) and specific surface area (SSA) was determined using spectrophotometry and methylene blue (MB). Thermal properties where determined by gravimetry (120, 350, 600 and 1000 oC) and differential thermal analysis (DTA). Quantitative mineral composition obtained by Rietveld refinement of combined chemical and XRD data shows that the sample 1(SC) is mainly smectite-illite (45%) and kaolinite (14%) clay with 19% of quartz, 10% feldspars and 7% of limonite, while sample 2(SV) is smectite-illite (43%) and kaolinite (11%) clay with 10% of quartz, 15% feldspars and 7% of limonite. Both samples have low content of impurities (carbonate minerals). Medium grain size (μm) goes from 1.02 (SSA = 104 m2/g) for sample 1(SC) to 0.71 (SSA = 117 m2/g) for sample 2(SV) while their CEC is 12.7 and 14.9 mmol/100g for 1(SC) and 2(SV) respectively. IR spectra of the samples shows larger amount of smectite clays with quartz and carbonate minerals for both samples which is in accordance with XRD data. DTA data shows couple of events that are endothermic. First one (100-200 oC) is associated with loss of moisture and constitutive water, second

  17. First direct detection of clay minerals on Mars

    NASA Astrophysics Data System (ADS)

    Singer, R. B.; Owensby, P. D.; Clark, R. N.

    1985-04-01

    Magnesian clays or clay-type minerals were conclusively detected in the martian regolith. Near-IR spectral observations of Mars using the Mauna Kea 2.2-m telescope show weak but definite absorption bands near microns. The absorption band positions and widths match those produced by combined OH stretch and Mg-OH lattice modes and are diagnostic of minerals with structural OH such as clays and amphiboles. Likely candidate minerals include serpentine, talc, hectorite, and sponite. There is no spectral evidence for aluminous hydroxylated minerals. No distinct band occurs at 2.55 microns, as would be expected if carbonates were responsible for the 2.35 micron absorption. High-albedo regions such as Elysium and Utopia have the strongest bands near 2.35 microns, as would be expected for heavily weathered soils. Low-albedo regions such as Iapygia show weaker but distinct bands, consistent with moderate coatings, streaks, and splotches of bright weathered material. In all areas observed, the 2.35-micron absorption is at least three times weaker than would be expected if well-crystallized clay minerals made up the bulk of bright soils on Mars.

  18. Kisameet Clay Exhibits Potent Antibacterial Activity against the ESKAPE Pathogens.

    PubMed

    Behroozian, Shekooh; Svensson, Sarah L; Davies, Julian

    2016-01-26

    The ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) pathogens cause an increasing number of nosocomial infections worldwide since they escape the inhibitory effect of the available antibiotics and the immune response. Here, we report the broad-spectrum and potent antibacterial activity of Kisameet clay, a natural clay mineral from British Columbia, Canada, against a group of multidrug-resistant ESKAPE strains. The results suggest that this natural clay might be developed as a therapeutic option for the treatment of serious infections caused by these important pathogens. More than 50 years of misuse and overuse of antibiotics has led to a plague of antibiotic resistance that threatens to reduce the efficacy of antimicrobial agents available for the treatment of infections due to resistant organisms. The main threat is nosocomial infections in which certain pathogens, notably the ESKAPE organisms, are essentially untreatable and contribute to increasing mortality and morbidity in surgical wards. The pipeline of novel antimicrobials in the pharmaceutical industry is essentially empty. Thus, there is a great need to seek for new sources for the treatment of recalcitrant infectious diseases. We describe experiments that demonstrate the efficacy of a "natural" medicine, Kisameet clay, against all of the ESKAPE strains. We suggest that this material is worthy of clinical investigation for the treatment of infections due to multidrug-resistant organisms. Copyright © 2016 Behroozian et al.

  19. First Direct Detection of Clay Minerals on Mars

    NASA Technical Reports Server (NTRS)

    Singer, R. B.; Owensby, P. D.; Clark, R. N.

    1985-01-01

    Magnesian clays or clay-type minerals were conclusively detected in the martian regolith. Near-IR spectral observations of Mars using the Mauna Kea 2.2-m telescope show weak but definite absorption bands near microns. The absorption band positions and widths match those produced by combined OH stretch and Mg-OH lattice modes and are diagnostic of minerals with structural OH such as clays and amphiboles. Likely candidate minerals include serpentine, talc, hectorite, and sponite. There is no spectral evidence for aluminous hydroxylated minerals. No distinct band occurs at 2.55 microns, as would be expected if carbonates were responsible for the 2.35 micron absorption. High-albedo regions such as Elysium and Utopia have the strongest bands near 2.35 microns, as would be expected for heavily weathered soils. Low-albedo regions such as Iapygia show weaker but distinct bands, consistent with moderate coatings, streaks, and splotches of bright weathered material. In all areas observed, the 2.35-micron absorption is at least three times weaker than would be expected if well-crystallized clay minerals made up the bulk of bright soils on Mars.

  20. Enhanced cellular preservation by clay minerals in 1 billion-year-old lakes

    NASA Astrophysics Data System (ADS)

    Wacey, David; Saunders, Martin; Roberts, Malcolm; Menon, Sarath; Green, Leonard; Kong, Charlie; Culwick, Timothy; Strother, Paul; Brasier, Martin D.

    2014-07-01

    Organic-walled microfossils provide the best insights into the composition and evolution of the biosphere through the first 80 percent of Earth history. The mechanism of microfossil preservation affects the quality of biological information retained and informs understanding of early Earth palaeo-environments. We here show that 1 billion-year-old microfossils from the non-marine Torridon Group are remarkably preserved by a combination of clay minerals and phosphate, with clay minerals providing the highest fidelity of preservation. Fe-rich clay mostly occurs in narrow zones in contact with cellular material and is interpreted as an early microbially-mediated phase enclosing and replacing the most labile biological material. K-rich clay occurs within and exterior to cell envelopes, forming where the supply of Fe had been exhausted. Clay minerals inter-finger with calcium phosphate that co-precipitated with the clays in the sub-oxic zone of the lake sediments. This type of preservation was favoured in sulfate-poor environments where Fe-silicate precipitation could outcompete Fe-sulfide formation. This work shows that clay minerals can provide an exceptionally high fidelity of microfossil preservation and extends the known geological range of this fossilization style by almost 500 Ma. It also suggests that the best-preserved microfossils of this time may be found in low-sulfate environments.

  1. Enhanced cellular preservation by clay minerals in 1 billion-year-old lakes.

    PubMed

    Wacey, David; Saunders, Martin; Roberts, Malcolm; Menon, Sarath; Green, Leonard; Kong, Charlie; Culwick, Timothy; Strother, Paul; Brasier, Martin D

    2014-07-28

    Organic-walled microfossils provide the best insights into the composition and evolution of the biosphere through the first 80 percent of Earth history. The mechanism of microfossil preservation affects the quality of biological information retained and informs understanding of early Earth palaeo-environments. We here show that 1 billion-year-old microfossils from the non-marine Torridon Group are remarkably preserved by a combination of clay minerals and phosphate, with clay minerals providing the highest fidelity of preservation. Fe-rich clay mostly occurs in narrow zones in contact with cellular material and is interpreted as an early microbially-mediated phase enclosing and replacing the most labile biological material. K-rich clay occurs within and exterior to cell envelopes, forming where the supply of Fe had been exhausted. Clay minerals inter-finger with calcium phosphate that co-precipitated with the clays in the sub-oxic zone of the lake sediments. This type of preservation was favoured in sulfate-poor environments where Fe-silicate precipitation could outcompete Fe-sulfide formation. This work shows that clay minerals can provide an exceptionally high fidelity of microfossil preservation and extends the known geological range of this fossilization style by almost 500 Ma. It also suggests that the best-preserved microfossils of this time may be found in low-sulfate environments.

  2. Enhanced cellular preservation by clay minerals in 1 billion-year-old lakes

    PubMed Central

    Wacey, David; Saunders, Martin; Roberts, Malcolm; Menon, Sarath; Green, Leonard; Kong, Charlie; Culwick, Timothy; Strother, Paul; Brasier, Martin D.

    2014-01-01

    Organic-walled microfossils provide the best insights into the composition and evolution of the biosphere through the first 80 percent of Earth history. The mechanism of microfossil preservation affects the quality of biological information retained and informs understanding of early Earth palaeo-environments. We here show that 1 billion-year-old microfossils from the non-marine Torridon Group are remarkably preserved by a combination of clay minerals and phosphate, with clay minerals providing the highest fidelity of preservation. Fe-rich clay mostly occurs in narrow zones in contact with cellular material and is interpreted as an early microbially-mediated phase enclosing and replacing the most labile biological material. K-rich clay occurs within and exterior to cell envelopes, forming where the supply of Fe had been exhausted. Clay minerals inter-finger with calcium phosphate that co-precipitated with the clays in the sub-oxic zone of the lake sediments. This type of preservation was favoured in sulfate-poor environments where Fe-silicate precipitation could outcompete Fe-sulfide formation. This work shows that clay minerals can provide an exceptionally high fidelity of microfossil preservation and extends the known geological range of this fossilization style by almost 500 Ma. It also suggests that the best-preserved microfossils of this time may be found in low-sulfate environments. PMID:25068404

  3. Mars, clays and the origins of life

    NASA Technical Reports Server (NTRS)

    Hartman, Hyman

    1989-01-01

    To detect life in the Martian soil, tests were designed to look for respiration and photosynthesis. Both tests (labeled release, LR, and pyrolytic release, PR) for life in the Martian soils were positive. However, when the measurement for organic molecules in the soil of Mars was made, none were found. The interpretation given is that the inorganic constituents of the soil of Mars were responsible for these observations. The inorganic analysis of the soil was best fitted by a mixture of minerals: 60 to 80 percent clay, iron oxide, quartz, and soluble salts such as halite (NaCl). The minerals most successful in simulating the PR and LR experiments are iron-rich clays. There is a theory that considers clays as the first organisms capable of replication, mutation, and catalysis, and hence of evolving. Clays are formed when liquid water causes the weathering of rocks. The distribution of ions such as aluminum, magnesium, and iron play the role of bases in the DNA. The information was stored in the distribution of ions in the octahedral and tetrahedral molecules, but that they could, like RNA and DNA, replicate. When the clays replicated, each sheet of clay would be a template for a new sheet. The ion substitutions in one clay sheet would give rise to a complementary or similar pattern on the clay synthesized on its surface. It was theorized that it was on the surface of replicating iron-rich clays that carbon dioxide would be fixed in the light into organic acids such as formic or oxalic acid. If Mars had liquid water during a warm period in its past, clay formation would have been abundant. These clays would have replicated and evolved until the liquid water was removed due to cooling of Mars. It is entirely possible that the Viking mission detected life on Mars, but it was clay life that awaits the return of water to continue its evolution into life based on organic molecules.

  4. Sulfonated Polyimide-Clay Thin Films for Energy Application.

    PubMed

    Ali, Farman; Saeed, Shaukat; Shah, Syed Sakhawat; Rahim, Fazal; Duclaux, Laurent; Levêque, Jean-Marc; Reinert, Laurence

    2016-01-01

    Sulfonated polyimides (SPIs) are considered as the promising alternatives to Nafion as membrane materials for the polymer electrolyte membrane (PEM). They generally exhibit high ionic conductivity, good mechanical properties, excellent thermal and chemical stabilities. The six-membered ring, naphthalenic anhydride-based SPIs, not only exhibit superior chemical and thermo-oxidative stabilities but are also more resistant to hydrolysis than their five-membered phthalic anhydride-based SPIs. The composites based on napthalenic polyimides are also significantly stable in high temperature environment and show better stability to hydrolysis. Incorporation of inorganic fillers into organic polymers has gained tremendous attention and these new materials are called organic-inorganic hybrids. Few patents related to the synthesis and performance PEM materials have been reviewed and cited. Keeping in view the importance of sulfonated polyimide based nanocomposites as potential membrane materials for PEM in fuel cell, we have synthesized SPIs clay based nanocomposite as potential membrane material. The objective of this work was to synthesize clay based SPIs thin films which could be used as membrane materials in PEM fuel cell for energy applications. Methods/Experimental: At the first step the nanometric sheets of vermiculite clay prepared via sonication was surface modified by grafting 3-APTES. Then the SPI was synthesized via one-step high temperature direct imidization method, which serve as a matrix material. The organo modified VMT was dispersed via sonication in the SPI matrix. Four different sets of organic-inorganic nanocomposite membranes thin films, having VMT contents in the range of 1 to 7 wt.% were prepared by casting, curing and acidification route. The synthesis of SPIs clay based thin films were carried out at three different steps and fully characterized. The synthesis of SPIs and SPIs clay based thin films were analyzed via different analytical techniques

  5. Formation of metal clusters in halloysite clay nanotubes

    DOE PAGES

    Vinokurov, Vladimir A.; Stavitskaya, Anna V.; Chudakov, Yaroslav A.; ...

    2017-02-16

    We developed ceramic core-shell materials based on abundant halloysite clay nanotubes with enhanced heavy metal ions loading through Schiff base binding. These clay tubes are formed by rolling alumosilicate sheets and have diameter of c.50 nm, a lumen of 15 nm and length ~1 μm. This allowed for synthesis of metal nanoparticles at the selected position: (1) on the outer surface seeding 3-5 nm metal particles on the tubes; (2) inside the tube’s central lumen resulting in 10-12 nm diameter metal cores shelled with ceramic wall; and (3) smaller metal nanoparticles intercalated in the tube’s wall allowing up to 9more » wt% of Ru, and Ag loading. These composite materials have high surface area providing a good support for catalytic nanoparticles, and can also be used for sorption of metal ions from aqueous solutions.« less

  6. Formation of metal clusters in halloysite clay nanotubes

    PubMed Central

    Vinokurov, Vladimir A.; Stavitskaya, Anna V.; Chudakov, Yaroslav A.; Ivanov, Evgenii V.; Shrestha, Lok Kumar; Ariga, Katsuhiko; Darrat, Yusuf A.; Lvov, Yuri M.

    2017-01-01

    Abstract We developed ceramic core-shell materials based on abundant halloysite clay nanotubes with enhanced heavy metal ions loading through Schiff base binding. These clay tubes are formed by rolling alumosilicate sheets and have diameter of c.50 nm, a lumen of 15 nm and length ~1 μm. This allowed for synthesis of metal nanoparticles at the selected position: (1) on the outer surface seeding 3–5 nm metal particles on the tubes; (2) inside the tube’s central lumen resulting in 10–12 nm diameter metal cores shelled with ceramic wall; and (3) smaller metal nanoparticles intercalated in the tube’s wall allowing up to 9 wt% of Ru, and Ag loading. These composite materials have high surface area providing a good support for catalytic nanoparticles, and can also be used for sorption of metal ions from aqueous solutions. PMID:28458738

  7. Provenance and recycling of Arabian desert sand

    NASA Astrophysics Data System (ADS)

    Garzanti, Eduardo; Vermeesch, Pieter; Andò, Sergio; Vezzoli, Giovanni; Valagussa, Manuel; Allen, Kate; Kadi, Khalid A.; Al-Juboury, Ali I. A.

    2013-05-01

    This study seeks to determine the ultimate origin of aeolian sand in Arabian deserts by high-resolution petrographic and heavy-mineral techniques combined with zircon U-Pb geochronology. Point-counting is used here as the sole method by which unbiased volume percentages of heavy minerals can be obtained. A comprehensive analysis of river and wadi sands from the Red Sea to the Bitlis-Zagros orogen allowed us to characterize all potential sediment sources, and thus to quantitatively constrain provenance of Arabian dune fields. Two main types of aeolian sand can be distinguished. Quartzose sands with very poor heavy-mineral suites including zircon occupy most of the region comprising the Great Nafud and Rub' al-Khali Sand Seas, and are largely recycled from thick Lower Palaeozoic quartzarenites with very minor first-cycle contributions from Precambrian basement, Mesozoic carbonate rocks, or Neogene basalts. Instead, carbonaticlastic sands with richer lithic and heavy-mineral populations characterize coastal dunes bordering the Arabian Gulf from the Jafurah Sand Sea of Saudi Arabia to the United Arab Emirates. The similarity with detritus carried by the axial Tigris-Euphrates system and by transverse rivers draining carbonate rocks of the Zagros indicates that Arabian coastal dunes largely consist of far-travelled sand, deposited on the exposed floor of the Gulf during Pleistocene lowstands and blown inland by dominant Shamal northerly winds. A dataset of detrital zircon U-Pb ages measured on twelve dune samples and two Lower Palaeozoic sandstones yielded fourteen identical age spectra. The age distributions all show a major Neoproterozoic peak corresponding to the Pan-African magmatic and tectonic events by which the Arabian Shield was assembled, with minor late Palaeoproterozoic and Neoarchean peaks. A similar U-Pb signature characterizes also Jafurah dune sands, suggesting that zircons are dominantly derived from interior Arabia, possibly deflated from the Wadi al

  8. Clay Mineral Structure Similar to Clays Observed in Mudstone on Mars

    NASA Image and Video Library

    2013-12-09

    This schematic shows the atomic structure of the smallest units that make up the layers and interlayer region of clay minerals. This structure is similar to the clay mineral in drilled rock powder collected by NASA Curiosity Mars rover.

  9. Selective Clay Placement Within a Silicate-Clay Epoxy Blend Nanocomposite

    NASA Technical Reports Server (NTRS)

    Miller, Sandi G (Inventor)

    2013-01-01

    A clay-epoxy nanocomposite may be prepared by dispersing a layered clay in an alkoxy epoxy, such as a polypropylene oxide based epoxide before combining the mixture with an aromatic epoxy to improve the nanocomposite's thermal and mechanical properties.

  10. Iodide uptake by negatively charged clay interlayers?

    PubMed

    Miller, Andrew; Kruichak, Jessica; Mills, Melissa; Wang, Yifeng

    2015-09-01

    Understanding iodide interactions with clay minerals is critical to quantifying risk associated with nuclear waste disposal. Current thought assumes that iodide does not interact directly with clay minerals due to electrical repulsion between the iodide and the negatively charged clay layers. However, a growing body of work indicates a weak interaction between iodide and clays. The goal of this contribution is to report a conceptual model for iodide interaction with clays by considering clay mineral structures and emergent behaviors of chemical species in confined spaces. To approach the problem, a suite of clay minerals was used with varying degrees of isomorphic substitution, chemical composition, and mineral structure. Iodide uptake experiments were completed with each of these minerals in a range of swamping electrolyte identities (NaCl, NaBr, KCl) and concentrations. Iodide uptake behaviors form distinct trends with cation exchange capacity and mineral structure. These trends change substantially with electrolyte composition and concentration, but do not appear to be affected by solution pH. The experimental results suggest that iodide may directly interact with clays by forming ion-pairs (e.g., NaI(aq)) which may concentrate within the interlayer space as well as the thin areas surrounding the clay particle where water behavior is more structured relative to bulk water. Ion pairing and iodide concentration in these zones is probably driven by the reduced dielectric constant of water in confined space and by the relatively high polarizability of the iodide species. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. New magnetic organic inorganic composites based on hydrotalcite-like anionic clays for drug delivery

    NASA Astrophysics Data System (ADS)

    Carja, Gabriela; Chiriac, Horia; Lupu, Nicoleta

    2007-04-01

    The structural "memory effect" of anionic clays was used to obtain layered double hydroxides (LDHs) with tailored magnetic properties, by loading iron oxides and/or spinel structures on iron partially substituted hydrotalcite-like materials. The obtained magnetic layered structures were further used as precursors for new hybrid nanostructures, such as aspirin-hydrotalcite-like anionic clays. Transmission electron microscopy (TEM) analysis shows that small iron oxide or spinel nanoparticles coexist with the fibrous drug particles on the surface of partially aggregated typical clay-like particles. The specific saturation magnetization of the loaded LDHs can be increased up to 70 emu/g by using specific post-synthesis treatments.

  12. Standardized wellheads proven economical for subsea operations

    SciTech Connect

    Moreira, C.C.; Silva Paulo, C.A. )

    1994-05-02

    A standardization program for subsea wellheads and completion equipment has made development of Brazil's offshore fields more economical and efficient. The resulting operational flexibility associated with the use of field-proven equipment and procedures saves rig time and can reduce production loss during workovers. Additionally, investments can be rationalized economically by installing part of the completion equipment at the end of the drilling job and then delaying purchase and installation of the christmas tree and the flow lines until installation of the production platform. Savings are also realized from the reduction in the number of spare parts and tools. Moreover, the savings related to improved operations exceed considerably those from equipment acquisition and storage. Thus, the greatest benefit is the operational flexibility. The paper discusses initial standards, the subsea programs, philosophy, implementation, diver-assisted trees, diverless trees, and economics.

  13. Titian: Data Provenance Support in Spark

    PubMed Central

    Interlandi, Matteo; Shah, Kshitij; Tetali, Sai Deep; Gulzar, Muhammad Ali; Yoo, Seunghyun; Kim, Miryung; Millstein, Todd; Condie, Tyson

    2015-01-01

    Debugging data processing logic in Data-Intensive Scalable Computing (DISC) systems is a difficult and time consuming effort. Today’s DISC systems offer very little tooling for debugging programs, and as a result programmers spend countless hours collecting evidence (e.g., from log files) and performing trial and error debugging. To aid this effort, we built Titian, a library that enables data provenance—tracking data through transformations—in Apache Spark. Data scientists using the Titian Spark extension will be able to quickly identify the input data at the root cause of a potential bug or outlier result. Titian is built directly into the Spark platform and offers data provenance support at interactive speeds—orders-of-magnitude faster than alternative solutions—while minimally impacting Spark job performance; observed overheads for capturing data lineage rarely exceed 30% above the baseline job execution time. PMID:26726305

  14. A unified framework for managing provenance information in translational research

    PubMed Central

    2011-01-01

    Background A critical aspect of the NIH Translational Research roadmap, which seeks to accelerate the delivery of "bench-side" discoveries to patient's "bedside," is the management of the provenance metadata that keeps track of the origin and history of data resources as they traverse the path from the bench to the bedside and back. A comprehensive provenance framework is essential for researchers to verify the quality of data, reproduce scientific results published in peer-reviewed literature, validate scientific process, and associate trust value with data and results. Traditional approaches to provenance management have focused on only partial sections of the translational research life cycle and they do not incorporate "domain semantics", which is essential to support domain-specific querying and analysis by scientists. Results We identify a common set of challenges in managing provenance information across the pre-publication and post-publication phases of data in the translational research lifecycle. We define the semantic provenance framework (SPF), underpinned by the Provenir upper-level provenance ontology, to address these challenges in the four stages of provenance metadata: (a) Provenance collection - during data generation (b) Provenance representation - to support interoperability, reasoning, and incorporate domain semantics (c) Provenance storage and propagation - to allow efficient storage and seamless propagation of provenance as the data is transferred across applications (d) Provenance query - to support queries with increasing complexity over large data size and also support knowledge discovery applications We apply the SPF to two exemplar translational research projects, namely the Semantic Problem Solving Environment for Trypanosoma cruzi (T.cruzi SPSE) and the Biomedical Knowledge Repository (BKR) project, to demonstrate its effectiveness. Conclusions The SPF provides a unified framework to effectively manage provenance of translational

  15. Biopsy-proven childhood glomerulonephritis in Johor.

    PubMed

    Khoo, J J; Pee, S; Thevarajah, B; Yap, Y C; Chin, C K

    2004-06-01

    There has been no published study of biopsy-proven childhood glomerulonephritis in Malaysia. To determine the pattern of childhood glomerulonephritis in Johor, Malaysia from a histopathological perspective and the various indications used for renal biopsy in children. Retrospective study was done of all renal biopsies from children under 16 years of age, received in Sultanah Aminah Hospital, Johor between 1994 and 2001. The histopathological findings were reviewed to determine the pattern of biopsy-proven glomerulonephritis. The indications for biopsy, mode of therapy given after biopsy and the clinical outcome were studied. 122 adequate biopsies were received, 9 children had repeat biopsies. Of the 113 biopsies, minimal change disease formed the most common histopathological diagnosis (40.7%) while lupus nephritis formed the most common secondary glomerulonephritis (23.0%). The main indications for biopsy were nephrotic syndrome (50.8%), lupus nephritis (25.4%) and renal impairment (13.1%). The mode of therapy was changed in 59.8% of the children. Of 106 patients followed-up, 84 children were found to have normal renal function in remission or on treatment. 4 patients developed chronic renal impairment and 16 reached end stage renal disease. Five of the 16 children with end stage disease had since died while 11 were on renal replacement therapy. Another 2 patients died of other complications. The pattern of childhood GN in our study tended to reflect the more severe renal parenchymal diseases in children and those requiring more aggressive treatment. This was because of our criteria of selection (indication) for renal biopsy. Renal biopsy where performed appropriately in selected children may not only be a useful investigative tool for histological diagnosis and prognosis but may help clinicians plan the optimal therapy for these children.

  16. Multitechnique characterization of lapis lazuli for provenance study.

    PubMed

    Lo Giudice, Alessandro; Re, Alessandro; Calusi, Silvia; Giuntini, Lorenzo; Massi, Mirko; Olivero, Paolo; Pratesi, Giovanni; Albonico, Maria; Conz, Elisa

    2009-12-01

    Lapis lazuli is one of the oldest precious stone, being used for glyptic as early as 7,000 years ago: jewels, amulets, seals, and inlays are examples of objects produced using this material. Only a few sources of lapis lazuli exist in the world due to the low probability of geological conditions in which it can form, so that the possibility to associate the raw material to man-made objects helps to reconstruct trade routes. Since art objects produced using lapis lazuli are valuable, only nondestructive investigations can be carried out to identify the provenance of the raw materials. Ionoluminescence (IL) is a good candidate for this task. Similar to cathodoluminescence (CL), IL consists in the collection of luminescence spectra induced by megaelectronvolt ion (usually protons) irradiation. The main advantage of IL consists in the possibility of working in air while measuring simultaneously the composition of major and trace elements by means of complementary ion beam analysis techniques like particle-induced X-ray emission (PIXE) or particle-induced gamma-ray emission (PIGE). In the present work, a systematic study of the luminescence properties of lapis lazuli under charged particle irradiation is reported. In the first phase, a multitechnique approach was adopted (CL, scanning electron microscopy with microanalysis, micro-Raman) to characterize luminescent minerals. This characterization was propaedeutic for IL/PIXE/PIGE measurements carried out on significant areas selected on the basis of results obtained previously. Criteria to identify provenance of lapis lazuli from four of the main sources (Afghanistan, Pamir Mountains in Tajikistan, Chile, and Siberia) were proposed.

  17. Interaction of ordinary Portland cement and Opalinus Clay: Dual porosity modelling compared to experimental data

    NASA Astrophysics Data System (ADS)

    Jenni, A.; Gimmi, T.; Alt-Epping, P.; Mäder, U.; Cloet, V.

    2017-06-01

    Interactions between concrete and clays are driven by the strong chemical gradients in pore water and involve mineral reactions in both materials. In the context of a radioactive waste repository, these reactions may influence safety-relevant clay properties such as swelling pressure, permeability or radionuclide retention. Interfaces between ordinary Portland cement and Opalinus Clay show weaker, but more extensive chemical disturbance compared to a contact between low-pH cement and Opalinus Clay. As a consequence of chemical reactions porosity changes occur at cement-clay interfaces. These changes are stronger and may lead to complete pore clogging in the case of low-pH cements. The prediction of pore clogging by reactive transport simulations is very sensitive to the magnitude of diffusive solute fluxes, cement clinker chemistry, and phase reaction kinetics. For instance, the consideration of anion-depleted porosity in clays substantially influences overall diffusion and pore clogging at interfaces. A new concept of dual porosity modelling approximating Donnan equilibrium is developed and applied to an ordinary Portland cement - Opalinus Clay interface. The model predictions are compared with data from the cement-clay interaction (CI) field experiment in the Mt Terri underground rock laboratory (Switzerland), which represent 5 y of interaction. The main observations such as the decalcification of the cement at the interface, the Mg enrichment in the clay detached from the interface, and the S enrichment in the cement detached from the interface, are qualitatively predicted by the new model approach. The model results reveal multiple coupled processes that create the observed features. The quantitative agreement of modelled and measured data can be improved if uncertainties of key input parameters (tortuosities, reaction kinetics, especially of clay minerals) can be reduced.

  18. Selective Clay Placement within a Silicate Clay-Epoxy Blend Nanocomposite and the Effect on Physical Properties

    NASA Technical Reports Server (NTRS)

    Miller, Sandi G.; Scheiman, Daniel A; Kohlmman, Lee W.

    2009-01-01

    Many epoxy systems under consideration for composite pressure vessels are composed of toughened epoxy resins. In this work, epoxy blends containing both rigid aromatic and flexible aliphatic components were prepared, to model toughened systems, and determine the optimum route of silicate addition. Compositions were chosen such that both glassy and rubbery resins were obtained at room temperature. The physical properties of the nanocomposites varied with T(g) and silicate placement, however, nanocomposite T(g)s were observed which exceeded that of the base resin by greater than 10 C. The tensile strength of the glassy resin remained constant or decreased on the dispersion of clay while that of the rubbery material doubled. Selectively placing the clay in the aliphatic component of the rubbery blend resulted in a greater than 100% increase in material toughness.

  19. Lapis lazuli provenance study by means of micro-PIXE

    NASA Astrophysics Data System (ADS)

    Re, Alessandro; Giudice, Alessandro Lo; Angelici, Debora; Calusi, Silvia; Giuntini, Lorenzo; Massi, Mirko; Pratesi, Giovanni

    2011-10-01

    In this paper we report about the micro-PIXE characterisation of lapis lazuli, for a provenance study of this semi-precious stone, used for glyptic as early as 7000 years ago. The final aim is to find markers permitting to identify the origin of the raw material coming from three quarries in regions of historical importance: Afghanistan, Pamir Mountains and Siberia. This may help to reconstruct trade routes, especially for ancient objects for which written testimonies are scanty or absent at all. Due to the heterogeneity of lapis lazuli we concentrate our attention on single phases instead of the whole stone; in particular we focused on two of the main phases: lazurite, responsible for the blue colour, and diopside, the most frequent accessory mineral. This study was preceded and completed by means of microanalysis with Scanning Electron Microscopy (SEM-EDX) and Cold-Cathodoluminescence (cold-CL) analysis. Despite the limited number of analysed samples, results are sufficient to exclude/suggest a few features as provenance markers, partly confirming what has been previously published in literature.

  20. Potential and pitfalls in establishing the provenance of Earth-related samples in forensic investigations.

    PubMed

    Rawlins, Barry G; Kemp, Simon J; Hodgkinson, Emily H; Riding, James B; Vane, Christopher H; Poulton, Catherine; Freeborough, Katy

    2006-07-01

    Earth scientists are often asked to establish or constrain the likely provenance of very small quantities of earth-related material as part of a forensic investigation. We tested the independent and collective interpretations of four experts with differing analytical skills in the prediction of sample provenance for three samples from different environmental settings. The methods used were X-ray diffraction, scanning electron microscopy, the assessment of pollen assemblages, and structural characterization of organic matter at the molecular level. Independent interpretations were less accurate than those where multiple techniques were combined. Collective interpretation was very effective in the assessment of provenance for two of the three sites where the mineralogy and plant communities were distinctive. At the other site, although the mineralogical analysis correctly identified the Triassic mudstone soil parent material, Carboniferous spores from domestic coal were initially interpreted as deriving directly from bedrock. Such an interpretation could be a common pitfall owing to anthropogenic redistribution of material such as coal.

  1. Fire performance of fiber board coated with nano kaolin-clay film

    Treesearch

    Zhijia Liu; John F. Hunt; Zhiyong Cai

    2013-01-01

    Fiberboard is a common interior material used both in China and the United States of America. The increase in demand for interior materials has raised concerns regarding combustibility of the materials. The pyrolysis characteristics of fiber, phenolic resin (PF), and nano kaolin-clay (NK) were investigated using thermogravimetry. The fire performances of samples coated...

  2. Clay Nanocomposite/Aerogel Sandwich Structures for Cryotanks

    NASA Technical Reports Server (NTRS)

    Miller, Sandi; Leventis, Nicholas; Johnston, J. Chris; Meador, Michael

    2006-01-01

    GRC research has led to the development of epoxy-clay nanocomposites with 60-70% lower gas permeability than the base epoxy resin. Filament wound carbon fiber reinforced tanks made with this nanocomposite had a five-fold lower helium leak rate than the corresponding tanks made without clay. More recent work has produced new composites with more than a 100-fold reduction in helium permeability. Use of these advanced, high barrier composites would eliminate the need for a liner in composite cryotanks, thereby simplifying construction and reducing propellant leakage. Aerogels are attractive materials for use as cryotank insulation because of their low density and low thermal conductivity. However, aerogels are fragile and have poor environmental stability, which have limited their use to certain applications in specialized environments (e.g., in certain types of nuclear reactors as Cerenkov radiation detectors, and as thermal insulators aboard space rovers on Mars). New GRC developed polymer crosslinked aerogels (X-Aerogels) retain the low density of conventional aerogels, but they demonstrate a 300-fold increase in their mechanical strength. Currently, our strongest materials combine a density of approx. 0.45 g/cc, a thermal conductivity of approx. 0.04 W/mK and a compressive strength of 185 MPa. Use of these novel aerogels as insulation materials/structural components in combination with the low permeability of epoxy-clay nanocomposites could significantly reduce cryotank weight and improve durability.

  3. Freeze-agglomeration: An alternative mechanism for clay film formation

    USDA-ARS?s Scientific Manuscript database

    Oriented clay coatings (argillans, clay cutans, clay films, lamellae) are often interpreted to be caused by illuviation (pervection, lessivage) of fine clay particles. In montane meadow soils (Typic Humaquepts) of the northern Sierra Nevada Range, prominent clay cutans occur on ped faces of a paleos...

  4. Mineralogy of subducted clay and clay restite in the lower mantle

    NASA Astrophysics Data System (ADS)

    Armstrong, L.; Skora, S. E.; Walter, M. J.

    2012-12-01

    Seismic tomography indicates that subducting oceanic lithosphere often penetrates the transition zone and eventually the lower mantle [e.g. 1, 2]. While mineralogical changes in the mafic and ultramafic portions of slabs have been well documented experimentally, the phase relations of overlying sediments at pressures above 25 GPa remain poorly studied. This is in part because sediments are expected to partially melt at sub-arc depth (P~2.5-4.5 GPa), and contribute to the genesis of arc magmas. Sediment restites left behind after the extraction of low pressure melts undergo major chemical changes, according to the melting reaction: Coe+Phen+Cpx+H2O = Grt+Ky+Melt [3]. However, sediments may not always melt depending on the thermal regime and volatile availability and composition [3]. Hence, chemically unmodified sediments as well as restites may be entrained to greater depths and contribute to compositional heterogeneity in the deep mantle. Indeed, mineral inclusions with compositions indicative of subducted sedimentary protoliths (CAS-phase; K-hollandite; stishovite) have been reported in 'ultradeep' diamonds and suggest that deep subduction and survival of sediments occurs to at least transition zone depths [4]. With this in mind, we have performed laser heated diamond anvil cell experiments at pressures of 8-80 GPa on two anhydrous glass starting materials: a marine clay and the restite that is left after 50% melt extraction of this clay at 3 GPa and 800 °C [3]. We chose to work with an anhydrous version of the marine clay given that the investigated pressure range exceeds that of phengite stability [5], and phengite is the only hydrous phase in subducted sediments at UHP conditions. The clay was heated along a P-T path representative of a cold subduction geotherm, whereas the clay restite was heated along a hotter subduction geotherm consistent with low pressure melting. Phases were identified by synchrotron X-ray micro-diffraction at beamline I15 of the Diamond

  5. Dramatical Impact Of Low Amounts of Swelling Clays On The Rheology Of Alpine Debris Flows

    NASA Astrophysics Data System (ADS)

    Bardou, E.; Bowen, P.; Banfill, P. G.; Boivin, P.

    2004-12-01

    Field observations show that the role and amount of swelling clays in the complex hard suspensions of alpine debris flow type were underestimated (see Boivin et al., this session). This work aims at exploring to which extent the swelling clay content influences the global rheology of a flow of rock grains from which the size spectrum extends from clays to gravel. We made a sample from calibrated materials with a grain size distribution similar to that of a viscoplastic debris flow (Bardou et al., 2003). Four replicates were made with the same grading curve. The clay content of the samples was 2% dry weight only, and different 2:1 swelling clay to 1:1 clay ratio were used. The swelling clay ratio (SCR) was calculated as the percentage of 2:1 clay in the clay fraction of the bulk samples. The 1:1 clay was (industrial) kaolinite and the 2:1 clay was a natural soil smectite. The smectite content in the bulk sample ranged from 0% to 2% dry weight, corresponding to SCR ranging from 0 to 80%. The four prepared samples were sheared in the large-size apparatus fully described in Tattersall and Banfill (1983). This apparatus is based on the measure of the torque necessary to rotate an impeller immersed in the sample. The impeller has the form of an "H" and moves in a plane according to two parallel axes. The observed behaviour were very contrasted. The sample with SCR=0 was poorly sensitive to changes in the solid concentration, in contrast to the three samples with SCR>0. Moreover, a small change in the SCR of the clay fraction induced a dramatic change of the behaviour of the mixture. For SCR=0, only little changes in the rheological parameters of the bulk samples were observed with respect to changes in the solid concentration. On the contrary the rheological parameters of the bulk samples with SCR>0, apparently followed a power law according to solid concentration. These tests carried out in the laboratory accord with observations realised on natural debris flow material

  6. Provenance research: investigation of genetic diversity associated with geography

    Treesearch

    Robert Z. Callaham

    1963-01-01

    Provenance in forestry refers to the population of trees growing at n particular place of origin. Provenance research defines the genetic and environmental components of phenotypic variation associated with geographic source. Information on provenance is important in assuring sources of seed to give well-adapted, productive trees and in directing breeding of...

  7. Scientific Workflows + Provenance = Better (Meta-)Data Management

    NASA Astrophysics Data System (ADS)

    Ludaescher, B.; Cuevas-Vicenttín, V.; Missier, P.; Dey, S.; Kianmajd, P.; Wei, Y.; Koop, D.; Chirigati, F.; Altintas, I.; Belhajjame, K.; Bowers, S.

    2013-12-01

    The origin and processing history of an artifact is known as its provenance. Data provenance is an important form of metadata that explains how a particular data product came about, e.g., how and when it was derived in a computational process, which parameter settings and input data were used, etc. Provenance information provides transparency and helps to explain and interpret data products. Other common uses and applications of provenance include quality control, data curation, result debugging, and more generally, 'reproducible science'. Scientific workflow systems (e.g. Kepler, Taverna, VisTrails, and others) provide controlled environments for developing computational pipelines with built-in provenance support. Workflow results can then be explained in terms of workflow steps, parameter settings, input data, etc. using provenance that is automatically captured by the system. Scientific workflows themselves provide a user-friendly abstraction of the computational process and are thus a form of ('prospective') provenance in their own right. The full potential of provenance information is realized when combining workflow-level information (prospective provenance) with trace-level information (retrospective provenance). To this end, the DataONE Provenance Working Group (ProvWG) has developed an extension of the W3C PROV standard, called D-PROV. Whereas PROV provides a 'least common denominator' for exchanging and integrating provenance information, D-PROV adds new 'observables' that described workflow-level information (e.g., the functional steps in a pipeline), as well as workflow-specific trace-level information ( timestamps for each workflow step executed, the inputs and outputs used, etc.) Using examples, we will demonstrate how the combination of prospective and retrospective provenance provides added value in managing scientific data. The DataONE ProvWG is also developing tools based on D-PROV that allow scientists to get more mileage from provenance metadata

  8. Clay Generic Disposal System Model - Sensitivity Analysis for 32 PWR Assembly Canisters (+2 associated model files).

    SciTech Connect

    Morris, Edgar

    2014-10-01

    The Used Fuel Disposition Campaign (UFDC), as part of the DOE Office of Nuclear Energy’s (DOE-NE) Fuel Cycle Technology program (FCT) is investigating the disposal of high level radioactive waste (HLW) and spent nuclear fuela (SNF) in a variety of geologic media. The feasibility of disposing SNF and HLW in clay media has been investigated and has been shown to be promising [Ref. 1]. In addition the disposal of these wastes in clay media is being investigated in Belgium, France, and Switzerland. Thus, Argillaceous media is one of the environments being considered by UFDC. As identified by researchers at Sandia National Laboratory, potentially suitable formations that may exist in the U.S. include mudstone, clay, shale, and argillite formations [Ref. 1]. These formations encompass a broad range of material properties. In this report, reference to clay media is intended to cover the full range of material properties. This report presents the status of the development of a simulation model for evaluating the performance of generic clay media. The clay Generic Disposal System Model (GDSM) repository performance simulation tool has been developed with the flexibility to evaluate not only different properties, but different waste streams/forms and different repository designs and engineered barrier configurations/ materials that could be used to dispose of these wastes.

  9. Painting with Clay Van Gogh Style.

    ERIC Educational Resources Information Center

    Skophammer, Karen

    1999-01-01

    Discusses Vincent Van Gogh's painting "Starry Night" and describes a lesson where fifth- and sixth-grade students created their own version of the artwork. Explains that the students utilized four colors of Permoplast clay, using their hands and fingers as brushes and blending tools and the clay as paint. (CMK)

  10. Sectioning Clay Models Makes Anatomy & Development Tangible

    ERIC Educational Resources Information Center

    Howell, Carina Endres; Howell, James Endres

    2010-01-01

    Clay models have proved to be useful teaching aids for many topics in biology that depend on three-dimensional reasoning. Students studying embryonic development struggle to mentally reconstruct the three-dimensional structure of embryos and larvae by observing prepared slides of cross-sectional slices. Students who build clay models of embryos…

  11. Uranium in clays of crystalline rocks

    SciTech Connect

    Simmons, G.; Caruso, L.

    1985-03-10

    Uraniferous clay aggregates in several granites have been examined in detail with a scanning electron microscope (SEM) equipped with a high resolution backscattered electron detector (BSE) and an energy dispersive x-ray system (EDS). The same polished sections used for the microscope observations were irradiated with thermal neutrons and the etched lexan detectors were then used to determine the location of uranium with a spatial resolution of a few microns. A set of 100 samples of the following granites were used for this study: Carnmenellis granite of southwestern England, Conway and Mount Osceola granites of central New Hampshire, Sherman granite of Wyoming and Colorado, Granite Mountains granite of Wyoming, several granites from central Maine, and the Graniteville granite of Missouri. These samples contain clay rich regions as large as a few millimeters that appear to consist entirely of clay when examined with the petrographic microscope. The clays are smectite, nontronite, or vermiculite. The fission track detectors show uranium to be present within the regions. Close examination with the BSE and EDS, however, shows in every instance that the host for the uranium is not clay but clay-sized grains of the following minerals: bastnesite group, hematite, siderite, secondary monazite, secondary thorite, and several different Y-bearing niobates. This finding may have severe implications for the long-term retention of uranium and transuranic elements adsorbed on clay. Perhaps the presence of clay is not significant for the long-term retention of radioisotopes. 22 refs., 7 figs.

  12. Using Clay Therapy To Change Negative Behaviors.

    ERIC Educational Resources Information Center

    Kahn, Victoria

    This manual describes a clay therapy program appropriate for use with students having a variety of exceptionalities and in an age range from 6 to 18 years. Organization and staffing are briefly discussed followed by a list of long range goals (affective, motoric, and aesthetic), suggestions for clay therapy implementation to achieve these goals,…

  13. Clay smear: Review of mechanisms and applications

    NASA Astrophysics Data System (ADS)

    Vrolijk, Peter J.; Urai, Janos L.; Kettermann, Michael

    2016-05-01

    Clay smear is a collection of fault processes and resulting fault structures that form when normal faults deform layered sedimentary sections. These elusive structures have attracted deep interest from researchers interested in subsurface fluid flow, particularly in the oil and gas industry. In the four decades since the association between clay-smear structures and oil and gas accumulations was introduced, there has been extensive research into the fault processes that create clay smear and the resulting effects of that clay smear on fluid flow. We undertake a critical review of the literature associated with outcrop studies, laboratory and numerical modeling, and subsurface field studies of clay smear and propose a comprehensive summary that encompasses all of these elements. Important fault processes that contribute to clay smear are defined in the context of the ratio of rock strength and in situ effective stresses, the geometric evolution of fault systems, and the composition of the faulted section. We find that although there has been progress in all avenues pursued, progress has been uneven, and the processes that disrupt clay smears are mostly overlooked. We highlight those research areas that we think will yield the greatest benefit and suggest that taking these emerging results within a more process-based framework presented here will lead to a new generation of clay smear models.

  14. Sectioning Clay Models Makes Anatomy & Development Tangible

    ERIC Educational Resources Information Center

    Howell, Carina Endres; Howell, James Endres

    2010-01-01

    Clay models have proved to be useful teaching aids for many topics in biology that depend on three-dimensional reasoning. Students studying embryonic development struggle to mentally reconstruct the three-dimensional structure of embryos and larvae by observing prepared slides of cross-sectional slices. Students who build clay models of embryos…

  15. Clay Corner: Light up a Turkey.

    ERIC Educational Resources Information Center

    Hiller, Peter

    1998-01-01

    Presents two activities that enable students to work with clay: a tile project and turkey candle-holders. Explains that before students actually create their own projects, they get an opportunity to experience the clay itself. Asserts that the new vocabulary, unusual equipment, and intriguing techniques make ceramics a motivating activity. (CMK)

  16. Using Clay Therapy To Change Negative Behaviors.

    ERIC Educational Resources Information Center

    Kahn, Victoria

    This manual describes a clay therapy program appropriate for use with students having a variety of exceptionalities and in an age range from 6 to 18 years. Organization and staffing are briefly discussed followed by a list of long range goals (affective, motoric, and aesthetic), suggestions for clay therapy implementation to achieve these goals,…

  17. Clay nanotube composites for antibacterial nanostructured coatings

    NASA Astrophysics Data System (ADS)

    Boyer, Christen J.

    A surging demand for the development of new antimicrobial nanomaterials exists due to the frequency of medical device-associated infections and the transfer of pathogens from highly touched objects. Naturally occurring halloysite clay nanotubes (HNTs) have shown to be ideal particles for polymer reinforcement, time-release drug delivery, nano-reactor synthesis, and as substrate material for nanostructured coatings. This research demonstrates the feasibility of a novel method for coating HNTs with metals for antibacterial applications. The first ever ability to coat HNTs through electrolysis was developed for customizable and multi-functional antibacterial nanoparticle platforms. HNTs were investigated as substrate for the deposition of copper (Cu) and silver (Ag) metal nanoparticles through electrochemical syntheses, and as a platform for nano-structured antibacterial polymer composites. Characterization of interfacial and material properties demonstrated the feasibility of electrolysis as a new efficient and replicable nano-scale surface modification route. Methods of encapsulating HNTs in nanofibers, three-dimensional printer filaments, and multifunctional polymer rubbers were also realized. The nanofabrication methods, nanoparticles, and polymer composites created in this work were novel, scalable, easy-to-replicate, and displayed antibacterial features with tunable properties.

  18. Deep sea authigenic clays as a sink for seawater Mg through the Cenozoic

    NASA Astrophysics Data System (ADS)

    Dunlea, A. G.; Murray, R. W.; Ramos, D. S.; Higgins, J. A.

    2016-12-01

    The most enigmatic sink of many elements in the global ocean is the formation of authigenic aluminosilicates. Pelagic clays cover 40% of the seafloor and "reverse weathering" type reactions within this lithology have the potential to be a large sink of seawater Mg and affect carbon cycling in the ocean. We use pelagic clays from Integrated Ocean Drilling Program Expedition 329 Site U1366 in the South Pacific Gyre to track authigenic aluminosilicates with two complementary methods: (1) Mg isotopic analyses, and (2) bulk sediment geochemistry with provenance modeling. Mg isotopic analyses of the bulk, unleached clay samples reveal isotopic values significantly heavier than average continental crust (δ26Mg = -0.1 to -0.3%o) indicating significant authigenic uptake. The bulk sediment geochemistry (i.e., major, trace, rare earth element concentrations) and multivariate statistical models of provenance determine the mass fraction of six different sediment sources that mixed to create the sediments: Fe/Mn-oxyhydroxides, apatite, excess Si, dust, and two altered volcanic ashes. A significant correlation between the mass fraction of one of the specific altered ash end-member and the δ26Mg signature allows us to characterize and track the abundance of the authigenic aluminosilicate component downcore. Trends in the provenance models suggest that the elements that compose the authigenic aluminosilicates may originate from volcanic ash, biogenic Si, and/or hydrothermal plume deposits. We examine variations in the spatial and temporal contributions of each of these sources and assess how these variations may have affected the amount of Mg authigenically consumed by deep sea authigenic clays through the Cenozoic. If the authigenic aluminosilicates are created by "reverse weathering" reactions, their formation also has important implications for carbon cycling in the global ocean.

  19. Active containment systems incorporating modified pillared clays

    SciTech Connect

    Lundie, P. |; McLeod, N.

    1997-12-31

    The application of treatment technologies in active containment systems provides a more advanced and effective method for the remediation of contaminated sites. These treatment technologies can be applied in permeable reactive walls and/or funnel and gate systems. The application of modified pillared clays in active containment systems provides a mechanism for producing permeable reactive walls with versatile properties. These pillared clays are suitably modified to incorporate reactive intercalatants capable of reacting with both a broad range of organic pollutants of varying molecular size, polarity and reactivity. Heavy metals can be removed from contaminated water by conventional ion-exchange and other reactive processes within the clay structure. Complex contamination problems can be addressed by the application of more than one modified clay on a site specific basis. This paper briefly describes the active containment system and the structure/chemistry of the modified pillared clay technology, illustrating potential applications of the in-situ treatment process for contaminated site remediation.

  20. Release kinetics of volatiles from clay minerals

    NASA Astrophysics Data System (ADS)

    Clausen, Pascal

    2007-03-01

    Smectite clay minerals are known to have interesting sorption properties, but the prediction of the kinetics of desorption of volatile molecules from such clays remains a challenge. The aim of this work is to relate the isothermal rate of desorption of volatile molecules from cation exchanged smectite clays to the chemical structures and geometries of the interacting species (clay platelet surface, type of counter-ion, type of volatile). It is thought that the rate of desorption of the volatiles at a given time is governed by their instantaneous diffusion in the clay and in the gas phase, which in turns is dependent on the volatile's interaction with its chemical and geometrical environment. Therefore, in addition to isothermal desorption rate measurements by thermogravimetry, activation energies of desorption are measured and calculated and the interacting compounds are characterized in terms of their chemical structure and geometry.

  1. Multifaceted role of clay minerals in pharmaceuticals

    PubMed Central

    Khurana, Inderpreet Singh; Kaur, Satvinder; Kaur, Harpreet; Khurana, Rajneet Kaur

    2015-01-01

    The desirable physical and physiochemical properties of clay minerals have led them to play a substantial role in pharmaceutical formulations. Clay minerals like kaolin, smectite and palygorskite-sepiolite are among the world's most valuable industrial minerals and of considerable importance. The elemental features of clay minerals which caused them to be used in pharmaceutical formulations are high specific area, sorption capacity, favorable rheological properties, chemical inertness, swelling capacity, reactivity to acids and inconsiderable toxicity. Of course, these are highly cost effectual. This special report on clay minerals provides a bird's eye view of the chemical composition and structure of these minerals and their influence on the release properties of active medicinal agents. Endeavor has been made to rope in myriad applications depicting the wide acceptability of these clay minerals. PMID:28031881

  2. Clays and other minerals in prebiotic processes

    NASA Technical Reports Server (NTRS)

    Paecht-Horowitz, M.

    1984-01-01

    Clays and other minerals have been investigated in context with prebiotic processes, mainly in polymerization of amino acids. It was found that peptides adsorbed on the clay, prior to polymerization, influence the reaction. The ratio between the amount of the peptides adsorbed and that of the clay is important for the yield as well as for the degrees of polymerization obtained. Adsorption prior to reaction produces a certain order in the aggregates of the clay particles which might induce better reaction results. Excess of added peptides disturbs this order and causes lesser degrees of polymerization. In addition to adsorption, clays are also able to occlude between their layers substances out of the environment, up to very high concentrations.

  3. Multifaceted role of clay minerals in pharmaceuticals.

    PubMed

    Khurana, Inderpreet Singh; Kaur, Satvinder; Kaur, Harpreet; Khurana, Rajneet Kaur

    2015-11-01

    The desirable physical and physiochemical properties of clay minerals have led them to play a substantial role in pharmaceutical formulations. Clay minerals like kaolin, smectite and palygorskite-sepiolite are among the world's most valuable industrial minerals and of considerable importance. The elemental features of clay minerals which caused them to be used in pharmaceutical formulations are high specific area, sorption capacity, favorable rheological properties, chemical inertness, swelling capacity, reactivity to acids and inconsiderable toxicity. Of course, these are highly cost effectual. This special report on clay minerals provides a bird's eye view of the chemical composition and structure of these minerals and their influence on the release properties of active medicinal agents. Endeavor has been made to rope in myriad applications depicting the wide acceptability of these clay minerals.

  4. Bioremediation of PAHs and VOCs: Advances in clay mineral-microbial interaction.

    PubMed

    Biswas, Bhabananda; Sarkar, Binoy; Rusmin, Ruhaida; Naidu, Ravi

    2015-12-01

    Bioremediation is an effective strategy for cleaning up organic contaminants, such as polycyclic aromatic hydrocarbons (PAHs) and volatile organic compounds (VOCs). Advanced bioremediation implies that biotic agents are more efficient in degrading the contaminants completely. Bioremediation by microbial degradation is often employed and to make this process efficient, natural and cost-effective materials can serve as supportive matrices. Clay/modified clay minerals are effective adsorbents of PAHs/VOCs, and readily available substrate and habitat for microorganisms in the natural soil and sediment. However, the mechanism underpinning clay-mediated biodegradation of organic compounds is often unclear, and this requires critical investigation. This review describes the role of clay/modified clay minerals in hydrocarbon bioremediation through interaction with microbial agents in specific scenarios. The vision is on a faster, more efficient and cost-effective bioremediation technique using clay-based products. This review also proposes future research directions in the field of clay modulated microbial degradation of hydrocarbons. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Fine particle clay catalysts for coal liquefaction. Quarterly technical report, May 9, 1991--August 8, 1991

    SciTech Connect

    Olson, E.S.

    1991-12-31

    The efficient production of environmentally acceptable distillate fuels requires catalysts for hydrogenation and cleavage of the coal macromolecules and removal of oxygen, nitrogen, and sulfur heteroatoms. The goal of the proposed research is to develop new catalysts for the direct liquefaction of coal. This type of catalyst consists of fine clay particles that have been treated with reagents which form pillaring structures between the aluminosilicate layers of the clay. The pillars not only hold the layers apart but also constitute the active catalytic sites for hydrogenation of the coal and the solvent used in the liquefaction. The pillaring catalytic sites are composed of pyrrhotite, which has been previously demonstrated to be active for coal liquefaction. The pyrrhotite sites are generated in situ by sulfiding the corresponding oxyiron species. The size of the catalyst will be less than 40 nm in order to promote intimate contact with the coal material. Since the clays and reagents for pillaring and activating the clays are inexpensive, the catalysts can be discarded after use, rather than regenerated by a costly process. The proposed work will evaluate methods for preparing the fine particle iron-pillared clay dispersions and for activating the particles to generate the catalysts. Characterization studies of the pillared clays and activated catalysts will be performed. The effectiveness of the pillared clay dispersion for hydrogenation and coal liquefaction will be determined in several types of testing.

  6. Effect of the local clay distribution on the effective electrical conductivity of clay rocks

    NASA Astrophysics Data System (ADS)

    Cosenza, P.; Prêt, D.; Zamora, M.

    2015-01-01

    The "local porosity theory" proposed by Hilfer was revisited to develop a "local clay theory" (LCT) that establishes a quantitative relationship between the effective electrical conductivity and clay distribution in clay rocks. This theory is primarily based on a "local simplicity" assumption; under this assumption, the complexity of spatial clay distribution can be captured by two local functions, namely, the local clay distribution and the local percolation probability, which are calculated from a partitioning of a mineral map. The local clay distribution provides information about spatial clay fluctuations, and the local percolation probability describes the spatial fluctuations in the clay connectivity. This LCT was applied to (a) a mineral map made from a Callovo-Oxfordian mudstone sample and (b) (macroscopic) electrical conductivity measurements performed on the same sample. The direct and inverse modeling shows two results. First, the textural and classical model assuming that the electrical anisotropy of clay rock is mainly controlled by the anisotropy of the sole clay matrix provides inconsistent inverted values. Another textural effect, the anisotropy induced by elongated and oriented nonclayey grains, should be considered. Second, the effective conductivity values depend primarily on the choice of the inclusion-based models used in the LCT. The impact of local fluctuations of clay content and connectivity on the calculated effective conductivity is lower.

  7. Provenance of Norphlet sandstone, northern Gulf Coast

    SciTech Connect

    Ryan, W.P.; Ward, W.C.; Kuglar, R.L.

    1987-09-01

    The Upper Jurassic Norphlet sandstone of the northern Gulf Coast is predominantly subarkose, with some arkose in the eastern area and sublitharenite and quartzarenite in the western area. Despite great depths of burial and despite feldspar and rock-fragment constituents, diagenesis has not appreciably altered the composition of Norphlet sandstone. Therefore, reconstruction of original composition of Norphlet sandstone presented little difficulty. Variation in detrital modes of the Norphlet suggests compositionally distinct source terranes. Samples from Florida, Alabama, and Mississippi reflect the influence of metamorphic and plutonic rocks of the Appalachian Piedmont Province and of Triassic-Jurassic volcanic rocks. Sandstones in east Texas, northern Louisiana, and southern Arkansas were derived from sedimentary and metasedimentary rocks of the Ouachita system. The Arbuckle Mountains and Llano uplift may have supplied trace amounts of quartzo-feldspathic and volcanic-rock fragments to the extreme western part of the study area. Norphlet sandstones represent a mixture of collision-orogen-derived sediment from the Appalachian and/or Ouachita system and continental-block-derived sediment from paleohighs and uplifts within the Gulf basin. However, Norphlet sandstones plot in the craton-interior and transitional-continental fields on Q-F-L and QM-F-Lt tectonic-provenance diagrams, because of mineralogically mature source rocks, elimination of unstable grains by abrasion and sorting during deposition, and/or sediment mixing from different source terranes.

  8. Mineralogical and geochemical evidence of Quachita provenance

    SciTech Connect

    Sutton, S.J. . Dept. of Earth Resources); Land, L.S.; Hutson, F. . Dept. of Geological Science); Awwiller, D.N. . Dept. of Geology)

    1994-03-01

    Provenance of the extremely thick Ouachita flysch has not been specifically identified, despite several recent studies. Detrital mineral compositions, Sm-Nd model ages, and single zircon dates strongly suggest that several sources contributed sediment that became well-mixed before deposition. Sm-Nd model ages are nearly uniform for flysch samples, regardless of geographic position or exact stratigraphic position. These ages appear to rule out significant contribution by a Paleozoic island arc, and suggest a single source, multiple sources with similar model ages, or thorough mixing of sources with different model ages. In contrast, single zircon ages are variable, including Archean, Proterozoic, and Paleozoic ages. These ages indicate multiple sediment sources, including some external to North America. The zircon ages, however, may not be generally representative of Ouachita sediment sources because they were obtained on zircons far larger than typical Ouachita detrital zircons. The Sm-Nd model ages and single zircon ages can both be explained if sediment entering the Ouachita Trough came from multiple sources, but was already thoroughly mixed before entering the trough. Such mixing is also suggested by detrital mineral analyses. Muscovite, garnet, and tourmaline have been analyzed.

  9. Provenance, age, and environment of mid-Wisconsinan slackwater lake sediment in the St. Louis Metro East area, USA

    USGS Publications Warehouse

    Curry, B. Brandon; Grimley, D.A.

    2006-01-01

    Valleys tributary to the Mississippi River contain fossiliferous slackwater lake sediment (Equality Formation) deposited in response to aggradation of the Mississippi River valley during the last glaciation. In the St. Louis Metro East area, the lower part of the Equality Formation is primarily laminated, fossiliferous silt and clay deposited from about 44,150 to 24,310 14C yr B.P. The upper Equality Formation is primarily very fine sand to silt deposited from about 21,200 to 17,000 14C yr B.P. Among the four cores that sample this succession in the St. Louis Metro East area, core MNK-3 (38.64EN, 90.01EW) was selected for detailed study. Three sources are distinguished by the following characteristics: (1) gray smectite-quartz-Se-rich, feldspar-poor material of the Des Moines, Wadena, and James lobes; (2) reddish brown kaolinite-Cu-Fe-rich sediment of the Superior and Rainy lobes; and (3) brown illite-dolomite-Sr-rich sediment of the Lake Michigan and Green Bay lobes. The earliest sediments (44,150 to 41,700 14C yr B.P.) were derived from the central and western provenances and are chronocorrelative with the lower Roxana Silt. A hiatus occurred from about 41,700 to 29,030 14C yr B.P. when much of the middle Roxana Silt (Meadow Member) was deposited on adjacent uplands. The youngest sediment includes evidence of heightened activity of the Superior Lobe at about 29,000 14C yr B.P., the Lake Michigan and Green Bay lobes from about 25,000 to 24,000 14C yr B.P., and the Wadena-Des Moines-James lobes at about 21,000 14C yr B.P. ?? 2005 Society. Published by University of Washington. All rights reserved.

  10. Interfacial interactions between polyethylene matrix and clay layers in polyethylene/clay nanocomposites

    NASA Astrophysics Data System (ADS)

    Abu-Zurayk, R.

    2015-10-01

    Polyethylene/clay nanocomposites were prepared as blown films using different formulae (clay contents (4 and 6 wt%) and compatibilizer/clay ratio (1/2, 1.0, 2.0)). Structure and mechanical behaviour were tested. It was found that blown film extrusion process decreased the tactoids size and consequently enhanced the exfoliation degree of the clay layers inside the polymer matrix, which is due to the elongational stress during extrusion. Addition of clay had some effects on mechanical behaviour. There was an increase of yield strength (max 32%). Yield strength is related to the interfacial interaction between the polymer and the clay layers in the nanocomposites, which would be enhanced by enhancing the compatibility between polymer and clay layers. Correlation analysis showed good correlation between compatibility and interfacial interaction parameters, and between parameters of interfacial interaction, structure and yield strength.

  11. In situ synthesis, characterization, and catalytic performance of tungstophosphoric acid encapsulated into the framework of mesoporous silica pillared clay.

    PubMed

    Li, Baoshan; Liu, Zhenxing; Han, Chunying; Ma, Wei; Zhao, Songjie

    2012-07-01

    Mesoporous silica pillared clay (SPC) incorporated with tungstophosphoric acid (HPW) has been synthesized via in situ introducing P and W source in the acidic suspension of the clay interlayer template during the formation of the silica pillared clay. The samples were characterized by XRD, XRF, FT-IR, TG-DTA, N(2) adsorption-desorption, and SEM techniques. The results showed that the HPW formed by in situ method has been effectively introduced into the framework of mesoporous silica pillared clay and its Keggin structure remained perfectly after formation of the materials. In addition, samples with similar HPW loadings were also prepared by impregnation method using SPC as the support. HPW in the incorporated samples was better dispersed into the silica pillared clay than in the impregnated samples. The results of catalytic tests indicated that the encapsulated materials demonstrated better catalytic performance than the impregnated samples in oxidative desulfurization (ODS) of dibenzothiophene (DBT).

  12. Increasing of Mechanical Parameters of Clay soil Using Calcium Chloride

    NASA Astrophysics Data System (ADS)

    Beheshty, Seyyed Amir Hossein; Moosa Aniran, Mir; Firoozfar, Alireza; Kiamehr, Ramin

    2017-04-01

    Research on roads to increase the resistance of weak soils to build structures on it has been increased in recent years. The present article provide the effects of different mixtures containing calcium chloride solution and clay soil on mechanical parameters such as, compressibility, compressive strength, shear strength and durability characteristic. In this study also is investigated evaluation the effect of road subgrade based on proposed material. The used clay soil in this research was obtained from zanjan city where is located in northwestern of Iran. The obtained results show that the calcium chloride solution could play a major role in reducing the cost and required time for building roads and also building foundation on these types of soils.

  13. Processing, Characterization, and Modeling of Polymer/Clay Nanocomposite Foams

    NASA Astrophysics Data System (ADS)

    Jo, Choonghee; Naguib, Hani E.

    2007-04-01

    The effects of the material parameters and processing conditions on the foam morphologies, and mechanical properties of polymer/clay nanocomposite foams were studied. Microcellular closed-cell nanocomposite foams were manufactured with poly(methylmethacrylate) (PMMA) and high density polyethylene (HDPE), where the nanoclay loadings of 0.5, 1.0, and 2.0 wt% were used. The effect of clay contents and foaming conditions on the volume expansion ratio, cell size, elastic modulus, tensile strength, and elongation at break were investigated and compared between amorphous and semicrystalline polymers. An elastic modulus model for tensile behavior of foams was proposed by using the micromechanics theory. The model was expressed in terms of microstructural properties of polymer and physical properties of the foams. The tensile experimental data of the foams were compared with those predicted by the theoretical model.

  14. Mortar characterization study of unreinforced hollow clay tile masonry

    SciTech Connect

    Butala, M.B.

    1992-09-14

    This report presents the results of an investigation of mortar removed from existing hollow clay tile masonry walls in buildings located at the Oak Ridge Y-12 Plant. Primary purpose of this investigation was to evaluate the properties of existing mortar and provide a similar specification for the mortar to be used in construction of test specimens and test walls for the Hollow Clay Tile Wall Test Program. A mortar characterization study of mortar samples removed from walls in four buildings, 9207, 9206, 9204-2 and 9212 was performed by Testwell Craig Materials Consultants (TCMC) under subcontract to Martin Marietta Energy Systems, Inc (MMES). The mortar samples were collected by MMES and analyzed by TCMC in accordance with applicable ASTM standards. Petrographical and chemical analyses were performed. From the results of this investigation a mortar mix was prepared to resemble the properties of existing mortar.

  15. Securing Provenance of Distributed Processes in an Untrusted Environment

    NASA Astrophysics Data System (ADS)

    Syalim, Amril; Nishide, Takashi; Sakurai, Kouichi

    Recently, there is much concern about the provenance of distributed processes, that is about the documentation of the origin and the processes to produce an object in a distributed system. The provenance has many applications in the forms of medical records, documentation of processes in the computer systems, recording the origin of data in the cloud, and also documentation of human-executed processes. The provenance of distributed processes can be modeled by a directed acyclic graph (DAG) where each node represents an entity, and an edge represents the origin and causal relationship between entities. Without sufficient security mechanisms, the provenance graph suffers from integrity and confidentiality problems, for example changes or deletions of the correct nodes, additions of fake nodes and edges, and unauthorized accesses to the sensitive nodes and edges. In this paper, we propose an integrity mechanism for provenance graph using the digital signature involving three parties: the process executors who are responsible in the nodes' creation, a provenance owner that records the nodes to the provenance store, and a trusted party that we call the Trusted Counter Server (TCS) that records the number of nodes stored by the provenance owner. We show that the mechanism can detect the integrity problem in the provenance graph, namely unauthorized and malicious “authorized” updates even if all the parties, except the TCS, collude to update the provenance. In this scheme, the TCS only needs a very minimal storage (linear with the number of the provenance owners). To protect the confidentiality and for an efficient access control administration, we propose a method to encrypt the provenance graph that allows access by paths and compartments in the provenance graph. We argue that encryption is important as a mechanism to protect the provenance data stored in an untrusted environment. We analyze the security of the integrity mechanism, and perform experiments to measure

  16. Data Provenance Architecture for the Geosciences

    NASA Astrophysics Data System (ADS)

    Murphy, F.; Irving, D. H.

    2012-12-01

    The pace at which geoscientific insights inform societal development quickens with time and these insights drive decisions and actions of ever-increasing human and economic significance. Until recently academic, commercial and government bodies have maintained distinct bodies of knowledge to support scientific enquiry as well as societal development. However, it has become clear that the curation of the body of data is an activity of equal or higher social and commercial value. We address the community challenges in the curation of, access to, and analysis of scientific data including: the tensions between creators, providers and users; incentives and barriers to sharing; ownership and crediting. We also discuss the technical and financial challenges in maximising the return on the effort made in generating geoscientific data. To illustrate how these challenges might be addressed in the broader geoscientific domain, we describe the high-level data governance and analytical architecture in the upstream Oil Industry. This domain is heavily dependent on costly and highly diverse geodatasets collected and assimilated over timeframes varying from seconds to decades. These data must support both operational decisions at the minute-hour timefame and strategic and economic decisions of enterprise or national scale, and yet be sufficiently robust to last the life of a producing field. We develop three themes around data provenance, data ownership and business models for data curation. 1/ The overarching aspiration is to ensure that data provenance and quality is maintained along the analytical workflow. Hence if data on which a publication or report changes, the report and its publishers can be notified and we describe a mechanism by which dependent knowledge products can be flagged. 2/ From a cost and management point of view we look at who "owns" data especially in cases where the cost of curation and stewardship is significant compared to the cost of acquiring the data

  17. Magnetic fabric analyses in analogue models of clays

    NASA Astrophysics Data System (ADS)

    García-Lasanta, Cristina; Román-Berdiel, Teresa; Izquierdo-Llavall, Esther; Casas-Sainz, Antonio

    2017-04-01

    Anisotropy of magnetic susceptibility (AMS) studies in sedimentary rocks subjected to deformation indicate that magnetic fabrics orientation can be conditioned by multiple factors: sedimentary conditions, magnetic mineralogy, successive tectonic events, etc. All of them difficult the interpretation of the AMS as a marker of the deformation conditions. Analogue modeling allows to isolate the variables that act in a geological process and to determine the factors and in which extent they influence in the process. This study shows the magnetic fabric analyses applied to several analogue models developed with common commercial red clays. This material resembles natural clay materials that, despite their greater degree of impurities and heterogeneity, have been proved to record a robust magnetic signal carried by a mixture of para- and ferromagnetic minerals. The magnetic behavior of the modeled clay has been characterized by temperature dependent magnetic susceptibility curves (from 40 to 700°C). The measurements were performed combining a KLY-3S Kappabridge susceptometer with a CS3 furnace (AGICO Inc., Czech Republic). The obtained results indicate the presence of an important content of hematite as ferromagnetic phase, as well as a remarkable paramagnetic fraction, probably constituted by phyllosilicates. This mineralogy is common in natural materials such as Permo-Triassic red facies, and magnetic fabric analyses in these natural examples have given consistent results in different tectonic contexts. In this study, sedimentary conditions and magnetic mineralogy are kept constant and the influence of the tectonic regime in the magnetic fabrics is analyzed. Our main objective is to reproduce several tectonic contexts (strike-slip and compression) in a sedimentary environment where material is not yet compacted, in order to determine how tectonic conditions influence the magnetic fabric registered in each case. By dispersing the clays in water and after allowing their

  18. Magnetic fabric from Red clay sediments in the Chinese Loess Plateau

    PubMed Central

    Gong, Hujun; Zhang, Rui; Yue, Leping; Zhang, Yunxiang; Li, Jianxing

    2015-01-01

    Well-distributed eolian red clay in a wide area of northern China is believed to imply the onset of an ancient East Asian monsoon system since Late Miocene. Two continuous red clay sequences spanning the time interval 7–2.6 Ma and 11–2.6 Ma in the Chinese Loess Plateau was investigated to determine the magnetic orientation and grain alignment in the primary fabric of eolian sediments. The north-westerly orientation of the AMS of the eolian red clay sequences parallels the material transportation direction, which differs from the model that suggests that airborne dust from overlying loess-paleosol sequences were transported by the East Asian winter monsoon and fixed by the East Asian summer monsoon. Our results further reveal that present-day climate and air circulation patterns differ from those of the pre-Quaternary, and may provide evidence of a prevailing wind during deposition of the red clay. PMID:25913292

  19. Magnetic fabric from red clay sediments in the Chinese Loess Plateau.

    PubMed

    Gong, Hujun; Zhang, Rui; Yue, Leping; Zhang, Yunxiang; Li, Jianxing

    2015-04-27

    Well-distributed eolian red clay in a wide area of northern China is believed to imply the onset of an ancient East Asian monsoon system since Late Miocene. Two continuous red clay sequences spanning the time interval 7-2.6 Ma and 11-2.6 Ma in the Chinese Loess Plateau was investigated to determine the magnetic orientation and grain alignment in the primary fabric of eolian sediments. The north-westerly orientation of the AMS of the eolian red clay sequences parallels the material transportation direction, which differs from the model that suggests that airborne dust from overlying loess-paleosol sequences were transported by the East Asian winter monsoon and fixed by the East Asian summer monsoon. Our results further reveal that present-day climate and air circulation patterns differ from those of the pre-Quaternary, and may provide evidence of a prevailing wind during deposition of the red clay.

  20. The response of Opalinus Clay when exposed to cyclic relative humidity variations

    NASA Astrophysics Data System (ADS)

    Wild, Katrin M.; Walter, Patric; Amann, Florian

    2017-03-01

    Clay shale specimens were exposed to cyclic relative humidity (RH) variations to investigate the response of the material to natural environmental changes. Opalinus Clay, a clay shale chosen as host rock for nuclear waste disposal in Switzerland, was utilized. The specimens were exposed to stepwise relative humidity cycles in which they were alternately allowed to equilibrate at 66 and 93 % relative humidity. Principal strains were monitored throughout the experiments using strain gauges. After each relative humidity cycle, Brazilian tensile strength tests were performed to identify possible changes in tensile strength due to environmental degradation.Results showed that Opalinus Clay follows a cyclic swelling-shrinkage behaviour with irreversible expansion limited to the direction normal to bedding, suggesting that internal damage is restricted along the bedding planes. The Brazilian tensile strength in direction parallel and normal to bedding as well as the water retention characteristic remained unaffected by the RH variations.

  1. Recycling of sugarcane bagasse ash waste in the production of clay bricks.

    PubMed

    Faria, K C P; Gurgel, R F; Holanda, J N F

    2012-06-30

    This work investigates the recycling of sugarcane bagasse ash waste as a method to provide raw material for clay brick bodies, through replacement of natural clay by up 20 wt.%. Initially, the waste sample was characterized by its chemical composition, X-ray diffraction, differential thermal analysis, particle size, morphology and pollution potential. Clay bricks pieces were prepared, and then tested, so as to determine their technological properties (e.g., linear shrinkage, water absorption, apparent density, and tensile strength). The sintered microstructure was evaluated by scanning electron microscopy (SEM). It was found that the sugarcane bagasse ash waste is mainly composed by crystalline silica particles. The test results indicate that the sugarcane bagasse ash waste could be used as a filler in clay bricks, thus enhancing the possibility of its reuse in a safe and sustainable way.

  2. Epoxy-silica/clay nanocomposite for silver-based antibacterial thin coatings: Synthesis and structural characterization.

    PubMed

    Giraldo Mejía, Hugo Fernando; Yohai, Lucia; Pedetta, Andrea; Herrera Seitz, Karina; Procaccini, Raúl Ariel; Pellice, Sergio Antonio

    2017-12-15

    Development of new functional coatings in the field of health care, as antibacterial applications, deals with a straight control of the diffusive properties that rules the releasing of the active component. In this work, the development of a silver-rich nanocomposite thin coating, loaded with organically modified clay nanoparticles, is presented. The synthesis process included an environment-friendly silanization process of clay nanoparticles (Laponite® S482) with (3-glycidoxypropyl)trimethoxysilane (GPTMS) and the further hydrolytic condensation with tetraethoxysilane (TEOS). Silanization process and the obtained coatings were analysed by Fourier transformed infrared spectroscopy, UV-visible spectroscopy, X-ray diffraction, thermogravimetric curves and scanning electron microscopy. The silanization process of clay nanoparticles with the organically reactive alkyl alkoxysilane, allowed to stabilize and exfoliate the clay nanosheets within a hybrid organic-inorganic sol-gel material. Ring opening of grafted epoxy groups carried to an increasing of the basal spacing, of intercalated clay nanosheets, from 1.3 to 1.8nm. Moreover, incorporation of organically modified clay nanosheets introduced a significant stabilization on the development of silver nanoparticles inside the structure of the nanocomposite coating, retaining the silver inside the coating material and restricting the growing of silver nanoparticles on the surface of the coating. Antibacterial behaviour, against E. coli cultures, performed through agar diffusion tests, provided promising results that allow assuming that the studied nanocomposite coating serves as a reservoir of ionic silver, permitting the antibacterial effect. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Clay particles - potential of positron annihilation lifetime spectroscopy (PALS) for studying interlayer spacing

    NASA Astrophysics Data System (ADS)

    Fong, N.; Guagliardo, P.; Williams, J.; Musumeci, A.; Martin, D.; Smith, S. V.

    2011-01-01

    Characterisation of clays is generally achieved by traditional methods, such as X-ray diffraction (XRD) and transmission electron microscopy (TEM). However, clays are often difficult to characterise due to lack of long-range order, thus these tools are not always reliable. Because interlayer spacing in clays can be adjusted to house molecules, there is growing interest to use these materials for drug delivery. Positron annihilation lifetime spectroscopy (PALS) was examined as an alternative tool to characterise a series of well-known clays. XRD of two layered double hydroxides; MgAl-LDH and MgGd-LDH, natural hectorite, fluoromica and laponite, and their PALS spectra were compared. XRD data was used to calculate the interlayer d- spacing in these materials and results show a decrease in interlayer spacing as the heavy metal ions are substituted for those of large ionic radii. Similar results were obtained for PALS data. This preliminary study suggests PALS has potential as a routine tool for characterising clay particles. Further work will examine the sensitivity and reliability of PALS to percent of metal doping and hydration in clay microstructure.

  4. Data provenance assurance in the cloud using blockchain

    NASA Astrophysics Data System (ADS)

    Shetty, Sachin; Red, Val; Kamhoua, Charles; Kwiat, Kevin; Njilla, Laurent

    2017-05-01

    Ever increasing adoption of cloud technology scales up the activities like creation, exchange, and alteration of cloud data objects, which create challenges to track malicious activities and security violations. Addressing this issue requires implementation of data provenance framework so that each data object in the federated cloud environment can be tracked and recorded but cannot be modified. The blockchain technology gives a promising decentralized platform to build tamper-proof systems. Its incorruptible distributed ledger/blockchain complements the need of maintaining cloud data provenance. In this paper, we present a cloud based data provenance framework using block chain which traces data record operations and generates provenance data. We anchor provenance data records into block chain transactions, which provide validation on provenance data and preserve user privacy at the same time. Once the provenance data is uploaded to the global block chain network, it is extremely challenging to tamper the provenance data. Besides, the provenance data uses hashed user identifiers prior to uploading so the blockchain nodes cannot link the operations to a particular user. The framework ensures that the privacy is preserved. We implemented the architecture on ownCloud, uploaded records to blockchain network, stored records in a provenance database and developed a prototype in form of a web service.

  5. Automatic Provenance Recording for Scientific Data using Trident

    NASA Astrophysics Data System (ADS)

    Simmhan, Y.; Barga, R.; van Ingen, C.

    2008-12-01

    Provenance is increasingly recognized as being critical to the understanding and reuse of scientific datasets. Given the rapid generation of scientific data from sensors and computational model results, it is not practical to manually record provenance for data and automated techniques for provenance capture are essential. Scientific workflows provide a framework for representing computational models and complex transformations of scientific data, and present a means for tracking the operations performed to derive a dataset. The Trident Scientific Workbench is a workflow system that natively incorporates provenance capture of data derived as part of the workflow execution. The applications used as part of a Trident workflow can execute on a remote computational cluster, such as a supercomputing center on in the Cloud, or on the local desktop of the researcher, and provenance on data derived by the applications is seamlessly captured. Scientists also have the option to annotate the provenance metadata using domain specific tags such as, for example, GCMD keywords. The provenance records thus captured can be exported in the Open Provenance Model* XML format that is emerging as a provenance standard in the eScience community or visualized as a graph of data and applications. The Trident workflow system and provenance recorded by it has been successfully applied in the Neptune oceanography project and is presently being tested in the Pan-STARRS astronomy project. *http://twiki.ipaw.info/bin/view/Challenge/OPM

  6. Instrumental Neutron Activation Analysis and Multivariate Statistics for Pottery Provenance

    NASA Astrophysics Data System (ADS)

    Glascock, M. D.; Neff, H.; Vaughn, K. J.

    2004-06-01

    The application of instrumental neutron activation analysis and multivariate statistics to archaeological studies of ceramics and clays is described. A small pottery data set from the Nasca culture in southern Peru is presented for illustration.

  7. Ni clay neoformation on montmorillonite surface.

    PubMed

    Dähn, R; Scheidegger, A; Manceau, A; Schlegel, M; Baeyens, B; Bradbury, M H

    2001-03-01

    Polarized extended X-ray absorption fine structure spectroscopy (P-EXAFS) was used to study the sorption mechanism of Ni on the aluminous hydrous silicate montmorillonite at high ionic strength (0.3 M NaClO4), pH 8 and a Ni concentration of 0.66 mM. Highly textured self-supporting clay films were obtained by slowly filtrating a clay suspension after a reaction time of 14 days. P-EXAFS results indicate that sorbed Ni has a Ni clay-like structural environment with the same crystallographic orientation as montmorillonite layers.

  8. Extracellular enzymes and soil carbon dynamics: exploring the effects of soil clay minerals

    NASA Astrophysics Data System (ADS)

    Olagoke, Folasade; Kalbitz, Karsten; Vogel, Cordula

    2017-04-01

    The importance of extracellular enzymes (EEs) in soil biogeochemical processes is well established. EEs are particularly decisive for carbon cycling through decomposition of organic matter (OM). The effectiveness of EEs in the soil depends on a number of factors including the amount and composition of clay minerals. However, the impact of interactions between clay minerals and EEs on the turnover rate of soil OM vis-a-vis carbon cycling in the soil is still poorly understood. Effects of clay minerals on activities of EEs have been mostly studied using clay minerals isolated from the soil matrix. Thus, it is not well elucidated how representative these results are for in-situ conditions. In this study, we analyzed the effect of different amounts of clay minerals added to soil on the activities of EEs towards understanding the role of interaction between clay minerals and EEs in soil carbon dynamics. We investigated three enzymes, α-glucosidase (AG), β-glucosidase (BG) and cellobiohydrolase (CB), which are important for soil carbon cycling. All assay preparations and measurements were carried out using fluorometric methods (MUF based substrates). A clay mineral (montmorillonite) was added to soil materials at four levels increasing the clay content in a logarithmic scale: +0% (control); +0.1%; +1% and +10%. The effects of clay minerals on EEs were analysed in two phases: firstly, the effects on the enzymes present in the soil were determined, and secondly the effect on a commercial enzyme (AG) added to the soil was tested. First results revealed that increasing the clay content in the soil led to a reduction in the activity of EEs. For AG and BG, significant reduction in activity was noted (P < 0.05) when the soil enriched with clay minerals was compared to the control (no clay addition). The CB, on the other hand, showed no statistical differences between the control and all treatments with addition of clay minerals. Similarly, in the second experiment with the

  9. The provenance of Taklamakan desert sand

    NASA Astrophysics Data System (ADS)

    Rittner, Martin; Vermeesch, Pieter; Carter, Andrew; Bird, Anna; Stevens, Thomas; Garzanti, Eduardo; Andò, Sergio; Vezzoli, Giovanni; Dutt, Ripul; Xu, Zhiwei; Lu, Huayu

    2016-03-01

    Sand migration in the vast Taklamakan desert within the Tarim Basin (Xinjiang Uyghur Autonomous region, PR China) is governed by two competing transport agents: wind and water, which work in diametrically opposed directions. Net aeolian transport is from northeast to south, while fluvial transport occurs from the south to the north and then west to east at the northern rim, due to a gradual northward slope of the underlying topography. We here present the first comprehensive provenance study of Taklamakan desert sand with the aim to characterise the interplay of these two transport mechanisms and their roles in the formation of the sand sea, and to consider the potential of the Tarim Basin as a contributing source to the Chinese Loess Plateau (CLP). Our dataset comprises 39 aeolian and fluvial samples, which were characterised by detrital-zircon U-Pb geochronology, heavy-mineral, and bulk-petrography analyses. Although the inter-sample differences of all three datasets are subtle, a multivariate statistical analysis using multidimensional scaling (MDS) clearly shows that Tarim desert sand is most similar in composition to rivers draining the Kunlun Shan (south) and the Pamirs (west), and is distinctly different from sediment sources in the Tian Shan (north). A small set of samples from the Junggar Basin (north of the Tian Shan) yields different detrital compositions and age spectra than anywhere in the Tarim Basin, indicating that aeolian sediment exchange between the two basins is minimal. Although river transport dominates delivery of sand into the Tarim Basin, wind remobilises and reworks the sediment in the central sand sea. Characteristic signatures of main rivers can be traced from entrance into the basin to the terminus of the Tarim River, and those crossing the desert from the south to north can seasonally bypass sediment through the sand sea. Smaller ephemeral rivers from the Kunlun Shan end in the desert and discharge their sediment there. Both river run

  10. Everything is autoimmune until proven otherwise.

    PubMed

    Shoenfeld, Yehuda

    2013-10-01

    diseases that have either an inflammatory and/or specific autoimmune response, we have to keep an open eye because everything is potentially autoimmune until proven otherwise.

  11. Pathways to Provenance: "DACS" and Creator Descriptions

    ERIC Educational Resources Information Center

    Weimer, Larry

    2007-01-01

    "Describing Archives: A Content Standard" breaks important ground for American archivists in its distinction between creator descriptions and archival material descriptions. Implementations of creator descriptions, many using Encoded Archival Context (EAC), are found internationally. "DACS"'s optional approach of describing…

  12. Clay mineralogy of Pleistocene Lake Tecopa, Inyo County, California

    USGS Publications Warehouse

    Starkey, Harry C.; Blackmon, Paul D.

    1979-01-01

    Pleistocene Lake Tecopa in southeastern Inyo County, Calif., was formed when the Amargosa River was blocked at the southern end of its valley. The lake acted as a settling basin for detrital material being transported by the river. This detritus consisted of clays, quartz, feldspars, and micas which became mudstones and siltstones. These mudstones and siltstones, much eroded and dissected after the draining of the lake, extend over the entire basin and are interbedded with tuffs formed by the intermittent deposition of volcanic ashfalls in the former lake waters. These lightcolored mudstones and siltstones are tough and well indurated and break with a conchoidal fracture. The predominant clay mineral in these detrital beds is a lithiumbearing saponite, which is found not only in the lake beds but also in the area beyond the boundaries of the lake, especially in fluvial deposits in the drainage basin of the Amargosa River to the north. This saponite does not contain enough lithium to be classified as a hectorite, and we have observed no indications that this clay consists of a mixture of two phases, such as hectorite and a diluent. Some authigenic dioctahedral montmorillonite, found only in small quantities close to the tuffs, was formed by alteration of the volcanic glass of the tuffs and was then admixed with the overlying or underlying detrital clays. The only authigenic clay-type mineral found in any significant quantity is sepiolite, found near the edges of the lake basin and stratigraphically located mainly within a meter of the two uppermost tuffs. This sepiolite probably was precipitated when silica became available to the magnesium-bearing lake water through dissolution of the volcanic ash. Precipitation of sepiolite probably did not occur within the tuffs owing to the presence of alumina in solution. Zeolites were produced there and sepiolite formed outside the margins of the tuffs. Also formed by the high-pH lake waters were water-soluble minerals, which

  13. Gas flow modelling through clay and claystones

    NASA Astrophysics Data System (ADS)

    Alonso, E.

    2012-12-01

    Large scale gas flow experiments conducted in connection with nuclear waste disposal research have shown the dominant effect of "minor" details such as interfaces, contacts and layer boundaries. Even if the scale of the analysis is highly reduced, in search of homogeneous point-like conditions, a systematic development of preferential paths is very often reported. Small size samples become boundary value problems. Preferential paths, when their thickness is modified by the stress-strain response of the media, under the combined action of stress and fluid pressure changes, become highly conductive features for gas flow. The development of preferential paths for fluid flow has been approached in a simple manner by embedding a discontinuity feature into an otherwise continuous element which models clay or claystone matrix behavior. The joint is activated when tensile strains develop in the continuous element. Then, hydraulic properties (permeability, retention behavior) are modified by means of laws derived from the physics of flow in discontinuities. The outlined idea was incorporated into a full Thermo-Hydro-Mechanical finite element code (CODE_BRIGHT) which has a wide range of capabilities for the modeling of two-phase flow in elasto-viscoplastic porous materials. A particular aspect which required attention is the modeling of expansive and shrinkage behavior induced by suction changes. In this way, healing effects during re-saturation may be simulated. Two experimental programs on clay shale samples, performed under triaxial stress conditions will be discussed. In the first case samples of Opalinus shale were subjected to a series of gas pulse decay tests during the application of stress paths involving a particular sequence of confining stress and shearing up to failure. In the second experimental program, performed on a tertiary mudstone from the Norwegian shelf, attention was paid to the effect of bedding-induced anisotropy. Experimental results will be

  14. Relevance of pore fluid composition for the drained strength of clays

    NASA Astrophysics Data System (ADS)

    Spagnoli, Giovanni; Fernández-Steeger, Tomás.; Arnhardt, Christian; Stanjek, Helge; Azzam, Rafig; Feinendegen, Martin

    2010-05-01

    Classical soil mechanics based on the effective stress concept with water as second phase does not apply anymore for fine-grained materials. Since clays particles are per definition colloidal in size, their properties are determined and dominated by their large surface area and hence, by their surface forces. Therefore, other mechanism plays a role. Geotechnical properties of soils with different pore fluid are especially important for clays used in hydraulic barriers for landfills. Also in the petroleum engineering or in tunnelling engineering the mechanical properties of clays with different pore fluids could be very useful. Since for clays physical and chemical interactions are decisive, the pure mechanical model (e.g. shearing and contact among the particles) is coupled by other forces, typical for colloidal sized materials. If the diffuse double layer develops from the surface of the clay particles, the interactions of the layers should develop a repulsion. That would resist part of the normal stress and producing no shearing resistance. However, the clays show different properties, dependent on their mineralogy, which complicates their behaviour. Several drained shear stress with shear box have been performed on pure Kaolinite, Illite, Na-Smectite and Ca-smectite. Since the shear behaviour of clays is also controlled by chemical interactions, the clays were mixed with pore fluids with different dielectric constant (water, ethanol), electrolyte concentration (NaCl and CaCl2) and pH (ranging from 3 to 8). Different consolidation pressures (from 15 kPa to 400 kPa) have been used in order to better understand the influence of the pore fluids on the drained cohesion (c') and on friction angle (φ'). The materials were mixed with different consistency to form a paste. The consistency ranges from 0.65 to 0.85. The results show how the sensitive the clays to different pore fluids are. Besides, Kaolinite and Illite shows a shearing behaviour almost entirely controlled

  15. Sedimentary provenance of Maastrichtian oil shales, Central Eastern Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Fathy, Douaa; Wagreich, Michael; Mohamed, Ramadan S.; Zaki, Rafat

    2017-04-01

    Maastrichtian oil shales are distributed within the Central Eastern Desert in Egypt. In this study elemental geochemical data have been applied to investigate the probable provenance of the sedimentary detrital material of the Maastrichtian oil shale beds within the Duwi and the Dakhla formations. The Maastrichtian oil shales are characterized by the enrichment in Ca, P, Mo, Ni, Zn, U, Cr and Sr versus post-Archean Australian shales (PAAS). The chondrite-normalized patterns of the Maastrichtian oil shale samples are showing LREE enrichment, HREE depletion, slightly negative Eu anomaly, no obvious Ce anomaly and typical shale-like PAAS-normalized patterns. The total REE well correlated with Si, Al, Fe, K and Ti, suggesting that the REE of the Maastrichtian oil shales are derived from terrigenous source. Chemical weathering indices such as Chemical Index of Alteration (CIA), Chemical Proxy of Alteration (CPA) and Plagioclase Index of Alteration (PIA) indicate moderate to strong chemical weathering. We suggest that the Maastrichtian oil shale is mainly derived from first cycle rocks especially intermediate rocks without any significant inputs from recycled or mature sources. The proposed data illustrated the impact of the parent material composition on evolution of oil shale chemistry. Furthermore, the paleo-tectonic setting of the detrital source rocks for the Maastrichtian oil shale is probably related to Proterozoic continental island arcs

  16. Color measurement of methylene blue dye/clay mixtures and its application using economical methods

    NASA Astrophysics Data System (ADS)

    Milosevic, Maja; Kaludjerovic, Lazar; Logar, Mihovil

    2016-04-01

    Identifying the clay mineral components of clay materials by staining tests is rapid and simple, but their applicability is restricted because of the mutual interference of the common components of clay materials and difficulties in color determination. The change of color with concentration of the dye is related to the use of colorants as a field test for identifying clay minerals and has been improved over the years to assure the accuracy of the tests (Faust G. T., 1940). The problem of measurement and standardization of color may be solved by combination of colors observed in staining tests with prepared charts of color chips available in the Munsell Book of Color, published by Munsell Color Co. Under a particular set of illumination conditions, a human eye can achieve an approximate match between the color of the dyed clay sample and that of a standard color chip, even though they do have different spectral reflectance characteristics. Experiments were carried out with diffuse reflectance spectroscopy on selected clay samples (three montmorillonite, three kaolinite and one mix-layer clay samples) saturated with different concentration of methylene blue dye solution. Dominant wavelength and purity of the color was obtained on oriented dry samples and calculated by use of the I. C. I. (x, y) - diagram in the region of 400-700 nm (reflectance spectra) without MB and after saturation with different concentrations of MB solutions. Samples were carefully photographed in the natural light environment and processed with user friendly and easily accessible applications (Adobe color CC and ColorHexa encyclopedia) available for android phones or tablets. Obtained colors were compared with Munsell standard color chips, RGB and Hexa color standards. Changes in the color of clay samples in their interaction with different concentration of the applied dye together with application of economical methods can still be used as a rapid fieldwork test. Different types of clay

  17. Concentration rebound following in situ chemical oxidation in fractured clay.

    PubMed

    Mundle, Keely; Reynolds, David A; West, Michael R; Kueper, Bernard H

    2007-01-01

    A two-dimensional, transient-flow, and transport numerical model was developed to simulate in situ chemical oxidation (ISCO) of trichloroethylene and tetrachloroethylene by potassium permanganate in fractured clay. This computer model incorporates dense, nonaqueous phase liquid dissolution, reactive aquifer material, multispecies matrix diffusion, and kinetic formulations for the oxidation reactions. A sensitivity analysis for two types of parameters, hydrogeological and engineering, including matrix porosity, matrix organic carbon, fracture aperture, potassium permanganate dosage, and hydraulic gradient, was conducted. Remediation metrics investigated were the relative rebound concentrations arising from back diffusion and percent mass destroyed. No well-defined correlation was found between the magnitude of rebound concentrations during postremedy monitoring and the amount of contaminant mass destroyed during the application. Results indicate that all investigated parameters affect ISCO remediation in some form. Results indicate that when advective transport through the fracture is dominant relative to diffusive transport into the clay matrix (large System Peclet Number), permanganate is more likely to be flushed out of the system and treatment is not optimal. If the System Peclet Number is too small, indicating that diffusion into the matrix is dominant relative to advection through the fracture, permanganate does not traverse the entire fracture, leading to postremediation concentration rebound. Optimal application of ISCO requires balancing advective transport through the fracture with diffusive transport into the clay matrix.

  18. The use of clays to sequestrate organic pollutants. Leaching experiments.

    PubMed

    Gianotti, V; Benzi, M; Croce, G; Frascarolo, P; Gosetti, F; Mazzucco, E; Bottaro, M; Gennaro, M C

    2008-12-01

    Leaching experiments are performed from clay-pollutant systems in order to evaluate the capability of clays to sequestrate organic pollutants from wastewaters. Reference kaolinite KGa-1b, montmorrillonite SWy-2 and reference soil BCR-700 are the sorbent materials. 2,4,6-trichloroaniline (2,4,6-TCA) and 4-chlorophenol (4-CP) are the typical pollutants, sorbed at amounts of 10.0 mg g(-1) and 5.8 mg g(-1) on SWy-2 and 7.3 mg g(-1) and 2.2 mg g(-1) on KGa-1b, respectively. The leaching agents are ultrapure water and model solutions of acid rain and surface waters that simulate meteoric leaching. 1.0mM HNO(3), 1.0mM H(2)SO(4) solutions and a methanol/water 50/50 (v/v) mixture simulate leaching agents of industrial source. The results are compared and the preferential capability of the clays to sequestrate the more lipophilic 2,4,6-TCA is evidenced. The bond interactions are discussed and explained through preferential adsorption reactions. For montmorrillonite also a simultaneous intercalation in the phyllosilicate interlayer is proposed.

  19. Biofilm formation of Pasteurella multocida on bentonite clay.

    PubMed

    Rajagopal, Ramachandranpillai; Nair, Govindapillai Krishnan; Mini, Mangattumuruppel; Joseph, Leo; Saseendranath, Mapranath Raghavan; John, Koshy

    2013-06-01

    Biofilms are structural communities of bacterial cells enshrined in a self produced polymeric matrix. The studies on biofilm formation of Pasteurella multocida have become imperative since it is a respiratory pathogen and its biofilm mode could possibly be one of its virulence factors for survival inside a host. The present study describes a biofilm assay for P. multocida on inert hydrophilic material called bentonite clay. The potential of the organism to form in vitro biofilm was assessed by growing the organism under nutrient restriction along with the inert substrate bentonite clay, which will provide a surface for attachment. For quantification of biofilm, plate count by the spread plate method was employed. Capsule production of the attached bacteria was demonstrated by light microscopic examination following Maneval staining and capsular polysaccharide estimation was done using standard procedures. The biofilm formation peaked on the third day of incubation (1.54 ×10(6) cfu/g of bentonite clay) while the planktonic cells were found to be at a maximum on day one post inoculation (8.10 ×10(8) cfu/ml of the broth). Maneval staining of late logarithmic phase biofilm cultures revealed large aggregates of bacterial cells, bacteria appearing as chains or as a meshwork. The capsular polysaccharide estimation of biofilm cells revealed a 3.25 times increase over the planktonic bacteria. The biofilm cells cultured on solid media also produced some exclusive colony morphotypes.

  20. Nanocomposites of irradiated polypropylene with clay are degradable?

    NASA Astrophysics Data System (ADS)

    Komatsu, L. G. H.; Oliani, W. L.; Lugao, A. B.; Parra, D. F.

    2016-01-01

    In nowadays, polypropylene (PP) based nanocomposites containing organically modified montmorillonite (MMT), have gained great attention in the automobilistic industries, construction, paints, packageing, plastic components of the telecommunication industries. The HMSPP (high melt strength polypropylene) is a polypropylene modified by irradiation process, under acetylene atmosphere, in which irradiation occurs in 60Co gamma source. However, when those materials are submitted to environmental ageing nanocomposites demonstrated high decomposition level after 1 year. This fact can be due to presence the metallic ions present in the montmorillonite. The HMS-PP and the Cloisite 20A (MMT) were mixed in twin-screw extruder using maleic anhydride as compatibilizer. In this work two formulations of nanocomposites at 0.1 and 5 wt% of clay were submitted to the environmental and thermal ageing to analyze the effects of degradation on the HMSPP nanocomposites. The evaluation of thermal properties was analyzed by Differential Scanning Calorimetry (DSC) and the chemical alterations were investigated by Carbonyl Index (CI), through Fourier Transformed Infrared (FTIR) technique. The basal distance was measured by X-ray diffraction (DRX) and the clay elements were analyzed by X-ray Fluorescence (WDXRF). The aim of this work was to understand the effects of degradation of the HMS-PP/clay nanocomposites.