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Sample records for iron mineral core

  1. Maximum stellar iron core mass

    Indian Academy of Sciences (India)

    60, No. 3. — journal of. March 2003 physics pp. 415–422. Maximum stellar iron core mass. F W GIACOBBE. Chicago Research Center/American Air Liquide ... iron core compression due to the weight of non-ferrous matter overlying the iron cores within large .... thermal equilibrium velocities will tend to be non-relativistic.

  2. Maximum stellar iron core mass

    Indian Academy of Sciences (India)

    An analytical method of estimating the mass of a stellar iron core, just prior to core collapse, is described in this paper. The method employed depends, in part, upon an estimate of the true relativistic mass increase experienced by electrons within a highly compressed iron core, just prior to core collapse, and is significantly ...

  3. Iron-titanium oxide minerals and magnetic susceptibility anomalies in the Mariano Lake-Lake Valley cores - Constraints on conditions of uranium mineralization in the Morrison Formation, San Juan Basin, New Mexico

    International Nuclear Information System (INIS)

    Reynolds, R.L.; Fishman, N.S.; Scott, J.H.; Hudson, M.R.

    1986-01-01

    Petrographic study of the Mariano Lake-Lake Valley cores reveals three distinct zones of postdepositional alteration of detrital Fe-Ti (iron-titanium) oxide minerals in the Westwater Canyon Member of the Upper Jurassic Morrisson Formation. In the uranium-bearing and adjacent portions of the Westwater Canyon, these detrital Fe-Ti oxide minerals have been thoroughly altered by leaching of iron. Stratigraphically lower parts of the Westwater Canyon and the underlying Recapture Member are characterized by preservation of Fe-Ti oxide grains, primarily magnetite and ilmenite, and of hematite, and by an absence or uranium concentrations. Partly destroyed Fe-Ti oxide minerals occupy an interval between the zones of destruction and preservation. Alteration patterns of the Fe-Ti oxide minerals are reflected in bore-hole magnetic susceptibility logs. Magnetic susceptibility response in the upper parts of the Westwater Canyon Member is flat and uniformly <500 μSI units, but at greater depths it fluctuates sharply, from <1,000 to nearly 8,000 μSI units. The boundary between uniformly low and high magnetic susceptibility response corresponds closely to the interval that divides the zone of completely altered from the zone of preserved detrital Fe-Ti oxide minerals. The alteration pattern suggests that solutions responsible for destruction of the Fe-ti oxide minerals originated in the overlying Brushy Basin Member of the Morrison Formation. Previous studies indicate that these solutions were rich in soluble organic matter and perhaps in uranium. Uranium precipitation may have been controlled by a vertically fluctuation interface between organic-rich solutions and geochemically different fluids in which the detrital Fe-Ti oxide minerals were preserved

  4. Iron oxyhydroxide mineralization on microbial extracellular polysaccharides

    Energy Technology Data Exchange (ETDEWEB)

    Chan, Clara S.; Fakra, Sirine C.; Edwards, David C.; Emerson, David; Banfield, Jillian F.

    2010-06-22

    Iron biominerals can form in neutral pH microaerophilic environments where microbes both catalyze iron oxidation and create polymers that localize mineral precipitation. In order to classify the microbial polymers that influence FeOOH mineralogy, we studied the organic and mineral components of biominerals using scanning transmission X-ray microscopy (STXM), micro X-ray fluorescence ({mu}XRF) microscopy, and high-resolution transmission electron microscopy (HRTEM). We focused on iron microbial mat samples from a creek and abandoned mine; these samples are dominated by iron oxyhydroxide-coated structures with sheath, stalk, and filament morphologies. In addition, we characterized the mineralized products of an iron-oxidizing, stalk-forming bacterial culture isolated from the mine. In both natural and cultured samples, microbial polymers were found to be acidic polysaccharides with carboxyl functional groups, strongly spatially correlated with iron oxyhydroxide distribution patterns. Organic fibrils collect FeOOH and control its recrystallization, in some cases resulting in oriented crystals with high aspect ratios. The impact of polymers is particularly pronounced as the materials age. Synthesis experiments designed to mimic the biomineralization processes show that the polysaccharide carboxyl groups bind dissolved iron strongly but release it as mineralization proceeds. Our results suggest that carboxyl groups of acidic polysaccharides are produced by different microorganisms to create a wide range of iron oxyhydroxide biomineral structures. The intimate and potentially long-term association controls the crystal growth, phase, and reactivity of iron oxyhydroxide nanoparticles in natural systems.

  5. Environmental association of iron minerals and iron concentrations ...

    African Journals Online (AJOL)

    Environmental association of iron (Fe) minerals and Fe concentrations in soils close to the Kgwakgwe Mn oxide ore abandoned mine, Botswana are investigated in this study. Four hundred soil samples were obtained from a 4 km2 area close to the abandoned mine. The Fe minerals in the soil samples were identified by ...

  6. Atomic absorption assessment of mineral iron quantity in ferritin

    International Nuclear Information System (INIS)

    Marinova, M.; Vladimirova, L.

    2009-01-01

    Possibilities for quantitative determination of the number of iron atoms in the mineral core of ferritin by atomic absorption spectroscopy (AAS) are investigated in the work. Different measurements with AAS show an iron content from 1000 up to 4500 atoms per molecule ferritin. This motivated us to investigate the amount of iron in the Horse Spleen Ferritin with atomic absorption spectroscopy under application of the Bulgarian standard BDS EN 14082/2003 Foodstuffs - Determination of trace elements - Determination of lead, cadmium, zinc, copper, iron and chromium by atomic absorption spectrometry (AAS) after dry ashing. The obtained results give approx. 1800 atoms per molecule Ferritin. It is in accordance with previous results, published by leading researchers. The investigation of the iron content with AAS under the use of the Bulgarian standard is a good opportunity to study many other objects of biological interest. (authors)

  7. The nanophase iron mineral(s) in Mars soil

    Science.gov (United States)

    Banin, A.; Ben-Shlomo, T.; Margulies, L.; Blake, D. F.; Mancinelli, R. L.; Gehring, A. U.

    1993-01-01

    A series of surface-modified clays containing nanophase (np) iron oxide/oxyhydroxides of extremely small particle sizes, with total iron contents as high as found in Mars soil, were prepared by iron deposition on the clay surface from ferrous chloride solution. Comprehensive studies of the iron mineralogy in these "Mars-soil analogs" were conducted using chemical extractions, solubility analyses, pH and redox, x ray and electron diffractometry, electron microscopic imaging, specific surface area and particle size determinations, differential thermal analyses, magnetic properties characterization, spectral reflectance, and Viking biology simulation experiments. The clay matrix and the procedure used for synthesis produced nanophase iron oxides containing a certain proportion of divalent iron, which slowly converts to more stable, fully oxidized iron minerals. The clay acted as an effective matrix, both chemically and sterically, preventing the major part of the synthesized iron oxides from ripening, i.e., growing and developing larger crystals. The precipitated iron oxides appear as isodiametric or slightly elongated particles in the size range 1-10 nm, having large specific surface area. The noncrystalline nature of the iron compounds precipitated on the surface of the clay was verified by their complete extractability in oxalate. Lepidocrocite (gamma-FeOOH) was detected by selected area electron diffraction. It is formed from a double iron Fe(II)/Fe(III) hydroxy mineral such as "green rust," or ferrosic hydroxide. Magnetic measurements suggested that lepidocrocite converted to the more stable maghemite (gamma-Fe2O3) by mild heat treatment and then to nanophase hematite (alpha-Fe2O3) by extensive heat treatment. After mild heating, the iron-enriched clay became slightly magnetic, to the extent that it adheres to a hand-held magnet, as was observed with Mars soil. The chemical reactivity of the iron-enriched clays strongly resembles, and offers a plausible mechanism

  8. Advantages of iron core in a tokamak

    International Nuclear Information System (INIS)

    Bettis, E.S.; Ballou, J.K.; Becraft, W.R.; Peng, Y.K.M.; Watts, H.L.

    1977-01-01

    A quantitative comparison of the iron core vs air core concepts was carried out on a preliminary basis by using a representative tokamak reactor design with the following self-consistent reference parameters. In the area of plasma engineering, poloidal field and MHD equilibrium considerations with an unsaturated iron core is discussed. The question of proper poloidal field coils to maintain D-shaped plasmas of relatively high anti β (7%) with a saturated iron core is also discussed. Estimates of the required iron core size, volt seconds, magnetic flux and its influence on force loading on the superconducting toroidal field coils are shown. Conceptual designs of the mechanical structure of an iron core device are presented. Favorable impacts on the OH power supply cost and complexity are indicated

  9. The nanosphere iron mineral(s) in Mars soil

    Science.gov (United States)

    Banin, A.; Ben-Shlomo, T.; Margulies, L.; Blake, D. F.; Mancinelli, R. L.; Gehring, A. U.

    1993-01-01

    A series of surface-modified clays containing nanophase (np) iron/oxyhydroxides of extremely small particle sizes, with total iron contents as high as found in Mars soil, were prepared by iron deposition on the clay surface from ferrous chloride solution. Comprehensive studies of the iron mineralogy in these 'Mars-soil analogs' were conducted using chemical extractions, solubility analyses, pH and redox, x ray and electron diffractometry, electron microscopic imaging specific surface area and particle size determinations, differential thermal analyses, magnetic properties characterization, spectral reflectance, and Viking biology simulation experiments. The clay matrix and the procedure used for synthesis produced nanophase iron oxides containing a certain proportion of divalent iron, which slowly converts to more stable, fully oxidized iron minerals. The noncrystalline nature of the iron compounds precipitated on the surface of the clay was verified by their complete extractability in oxalate. Lepidocrocite (gamma-FeOOH) was detected by selected area electron diffraction. It is formed from a double iron Fe(II)/Fe(III) hydroxyl mineral such as 'green rust', or ferrosic hydroxide. Magnetic measurements suggested that lepidocrocite converted to the more stable meaghemite (gamma-Fe203) by mild heat treatment and then to nanophase hematite (aplha-Fe203) by extensive heat treatment. Their chemical reactivity offers a plausible mechanism for the somewhat puzzling observations of the Viking biology experiments. Their unique chemical reactivities are attributed to the combined catalytic effects of the iron oxide/oxyhydroxide and silicate phase surfaces. The mode of formation of these (nanophase) iron oxides on Mars is still unknown.

  10. On the collapse of iron stellar cores

    International Nuclear Information System (INIS)

    Barkat, Z.; Rakavy, G.; Reiss, Y.; Wilson, J.R.

    1975-01-01

    The collapse of iron stellar cores is investigated to see whether the outward shock produced by the bounce at neutron star density is sufficient to burn appreciable amounts of the envelope around the iron core. Several models were tried, and in all cases no appreciable burn took place; hence no explosion results from the collapse of these models

  11. Core-shell iron-iron oxide nanoparticles

    DEFF Research Database (Denmark)

    Kuhn, Luise Theil; Bojesen, A.; Timmermann, L.

    2004-01-01

    We present studies of the magnetic properties of core-shell iron-iron oxide nanoparticles. By combining Mossbauer and X-ray absorption spectroscopy we have been able to measure the change from a Fe3O4-like to a gamma-Fe2O3-like composition from the interface to the surface. Furthermore, we have...

  12. Extrap with iron-cored coils

    International Nuclear Information System (INIS)

    Lehnert, B.

    1985-05-01

    In Extrap configurations there is a high average beta value with respect to the plasma confinement volume. The externally imposed magnetic field which is required for stabilization therefore comes out to have a rather moderate strength, even under expected reactor conditions. As a consequence, this field can be generated not only by conventional external conductor arrangements, but also by iron-cored coils being operated below the saturation limit. A proposal for such iron-cored coil systems is presented in this paper. As compared to conventional conductors, this has the advantage of localizing the magnetic energy of the externally imposed magnetic field mainly to the discharge vessel and the plasma volume, thereby increasing the engineering beta value substantially. Also the problems of the coil stresses and of irradiation of the coils appear to become simplified, as well as replacement of the coil system. A main limitation of this proposal is due to combination of iron core saturation with the required stabilization effect from an ion Larmor radius of sufficient relative magnitude. This limitaion requires further investigation, especially in the full-scale reactor case. Also the modifications of the field geometry by iron core shaping needs further analysis. (Author)

  13. Formation and Reactivity of Biogenic Iron Minerals

    International Nuclear Information System (INIS)

    Ferris, F. Grant

    2002-01-01

    Dissimilatory iron-reducing bacteria (DIRB) play an important role in regulating the aqueous geochemistry of iron and other metals in anaerobic, non-sulfidogenic groundwater environments; however, little work has directly assessed the cell surface electrochemistry of DIRB, or the nature of the interfacial environment around individual cells. The electrochemical properties of particulate solids are often inferred from titrations in which net surface charge is determined, assuming electroneutrality, as the difference between known added amounts of acid and base and measured proton concentration. The resultant titration curve can then be fit to a speciation model for the system to determine pKa values and site densities of reactive surface sites. Moreover, with the development of non-contact electrostatic force microscopy (EFM), it is now possible to directly inspect and quantify charge development on surfaces. A combination of acid-base titrations and EFM are being used to assess the electrochemical surface properties of the groundwater DIRB, Shewanella putrefaciens. The pKa spectra and EFM data show together that a high degree of electrochemical heterogeneity exists within the cell wall and at the cell surface of S. putrefaciens. Recognition of variations in the nature and spatial distribution of reactive sites that contribute to charge development on these bacteria implies further that the cell surface of these Fe(III)-reducing bacteria functions as a highly differentiated interfacial system capable of supporting multiple intermolecular interactions with both solutes and solids. These include surface complexation reactions involving dissolved metals, as well as adherence to mineral substrates such as hydrous ferric oxide through longer-range electrostatic interactions, and surface precipitation of secondary reduced-iron minerals

  14. Reduction of iron-bearing lunar minerals for the production of oxygen

    Science.gov (United States)

    Massieon, Charles; Cutler, Andrew; Shadman, Farhang

    1992-01-01

    The kinetics and mechanism of the reduction of simulants of the iron-bearing lunar minerals olivine ((Fe,Mg)2SiO4), pyroxene ((Fe,Mg,Ca)SiO3), and ilmenite (FeTiO3) are investigated, extending previous work with ilmenite. Fayalite is reduced by H2 at 1070 K to 1480 K. A layer of mixed silica glass and iron forms around an unreacted core. Reaction kinetics are influenced by permeation of hydrogen through this layer and a reaction step involving dissociated hydrogen. Reaction mechanisms are independent of Mg content. Augite, hypersthene, and hedenbergite are reduced in H2 at the same temperatures. The products are iron metal and lower iron silicates mixed throughout the mineral. Activation energy rises with calcium content. Ilmenite and fayalite are reduced with carbon deposited on partially reduced minerals via the CO disproportionation reaction. Reduction with carbon is rapid, showing the carbothermal reduction of lunar minerals is possible.

  15. Iron snow in the Martian core?

    Science.gov (United States)

    Davies, Christopher J.; Pommier, Anne

    2018-01-01

    The decline of Mars' global magnetic field some 3.8-4.1 billion years ago is thought to reflect the demise of the dynamo that operated in its liquid core. The dynamo was probably powered by planetary cooling and so its termination is intimately tied to the thermochemical evolution and present-day physical state of the Martian core. Bottom-up growth of a solid inner core, the crystallization regime for Earth's core, has been found to produce a long-lived dynamo leading to the suggestion that the Martian core remains entirely liquid to this day. Motivated by the experimentally-determined increase in the Fe-S liquidus temperature with decreasing pressure at Martian core conditions, we investigate whether Mars' core could crystallize from the top down. We focus on the "iron snow" regime, where newly-formed solid consists of pure Fe and is therefore heavier than the liquid. We derive global energy and entropy equations that describe the long-timescale thermal and magnetic history of the core from a general theory for two-phase, two-component liquid mixtures, assuming that the snow zone is in phase equilibrium and that all solid falls out of the layer and remelts at each timestep. Formation of snow zones occurs for a wide range of interior and thermal properties and depends critically on the initial sulfur concentration, ξ0. Release of gravitational energy and latent heat during growth of the snow zone do not generate sufficient entropy to restart the dynamo unless the snow zone occupies at least 400 km of the core. Snow zones can be 1.5-2 Gyrs old, though thermal stratification of the uppermost core, not included in our model, likely delays onset. Models that match the available magnetic and geodetic constraints have ξ0 ≈ 10% and snow zones that occupy approximately the top 100 km of the present-day Martian core.

  16. Antioxidant mechanism of milk mineral-high-affinity iron binding.

    Science.gov (United States)

    Allen, K; Cornforth, D

    2007-01-01

    Milk mineral (MM), a by-product of whey processing, is an effective antioxidant in meat systems, but the antioxidant mechanism has not been established. MM has been postulated to chelate iron and prevent iron-catalysis of lipid oxidation. The objective of this research was to examine this putative mechanism. MM was compared to sodium tripolyphosphate (STPP), calcium phosphate monobasic (CPM), and calcium pyrophosphate (CPP) to determine iron-binding capacity, sample solubility, and eluate soluble phosphorus after treating samples with a ferrous chloride standard. Scanning electron microscopy with energy-dispersive X-ray analysis was used to localize minerals on iron-treated MM particle surfaces. Histochemical staining for calcium was performed on raw and cooked ground beef samples with added MM. MM bound more iron per gram (P compounds, and was much less soluble (P iron across the MM particle surface, directly demonstrating iron binding to MM particles. Unlike other common chelating agents, such as STPP and citrate, histochemical staining demonstrated that MM remained insoluble in ground beef, even after cooking. The ability of MM to bind iron and remain insoluble may enhance its antioxidant effect by removing iron ions from solution. However, MM particles must be small and well distributed in order to adequately bind iron throughout the food system.

  17. Alteration mineral mapping for iron prospecting using ETM+ data, Tonkolili iron field, northern Sierra Leone

    Science.gov (United States)

    Mansaray, Lamin R.; Liu, Lei; Zhou, Jun; Ma, Zhimin

    2013-10-01

    The Tonkolili iron field in northern Sierra Leone has the largest known iron ore deposit in Africa. It occurs in a greenstone belt in an Achaean granitic basement. This study focused mainly on mapping areas with iron-oxide and hydroxyl bearing minerals, and identifying potential areas for haematite mineralization and banded iron formations (BIFs) in Tonkolili. The predominant mineral assemblage at the surface (laterite duricrust) of this iron field is haematitegoethite- limonite ±magnetite. The mineralization occurs in quartzitic banded ironstones, layered amphibolites, granites, schists and hornblendites. In this study, Crosta techniques were applied on Enhanced Thematic Mapper (ETM+) data to enhance areas with alteration minerals and target potential areas of haematite and BIF units in the Tonkolili iron field. Synthetic analysis shows that alteration zones mapped herein are consistent with the already discovered magnetite BIFs in Tonkolili. Based on the overlaps of the simplified geological map and the remote sensing-based alteration mineral maps obtained in this study, three new haematite prospects were inferred within, and one new haematite prospect was inferred outside the tenement boundary of the Tonkolili exploration license. As the primary iron mineral in Tonkolili is magnetite, the study concludes that, these haematite prospects could also be underlain by magnetite BIFs. This study also concludes that, the application of Crosta techniques on ETM+ data is effective not only in mapping iron-oxide and hydroxyl alterations but can also provide a basis for inferring areas of potential iron resources in Algoma-type banded iron formations (BIFs), such as those in the Tonkolili field.

  18. Economic value of Valentines iron minerals

    International Nuclear Information System (INIS)

    Alvarado, B.

    1960-01-01

    This work is a investigation required by the government of Uruguay about the economic value of iron and manganese deposits in Valentines ferriferrous zone. The purpose is to study the potential commercial for the exportation.

  19. Toroidal equilibrium in an iron-core reversed field pinch

    International Nuclear Information System (INIS)

    Miller, G.

    1984-04-01

    An analytical theory of toroidal equilibrium in the ZT-40M reversed field pinch is obtained, including effects of iron cores and resistive shell. The iron cores alter the form of the equilibrium condition and cause the equilibrium to be unstable on the shell resistive time scale

  20. Review of Abiotic Degradation of Chlorinated Solvents by Reactive Iron Minerals

    Science.gov (United States)

    Abiotic degradation of chlorinated solvents by reactive iron minerals such as iron sulfides, magnetite, green rust, and other Fe(II)-containing minerals has been observed in both laboratory and field conditions. These reactive iron minerals typically form under iron and sulfate ...

  1. Minerals of oxidation zone of the Chokadambulaq iron deposit

    International Nuclear Information System (INIS)

    Safaraliev, N.S.

    2008-01-01

    The zone of oxidation of Chokadambulaq iron deposit has original mineral composition, which characterized specificity of their formation. Here is formed a secondary zone of enrichment marit ores, having practical meaning. In last is concentrated from 0.5 up to 1.0% from total quantities of reserves

  2. Moessbauer spectroscopy of iron in clay minerals

    International Nuclear Information System (INIS)

    Raclavsky, K.; Sitek, J.; Lipka, J.

    1975-01-01

    Selected pure clay minerals predominantly of Czechoslovak origin were studied, such as montmorillonite, nontronite, beidellite, glauconite, seladonite, illite, vermiculite, saponite, palygorskite, goethite. Moessbauer measurements were performed at room temperature with a 57 Co in Pd source. The spectra were fitted by the least square method. The parameters of the measured Moessbauer spectra are given. The values of isomer shifts, quadrupole splittings and line widths were obtained with an error of +- 0.03 mm/sec. (Z.S.)

  3. Vortex core properties in iron pnictides

    Directory of Open Access Journals (Sweden)

    Zakharchuk I.

    2014-07-01

    Full Text Available The mechanism of unconventional superconductivity in recently discovered Fe-based superconductors has been intensively discussed. A plausible candidate is the superconducting (SC pairing mediated by antiferromagnetic (AFM interactions. There are two different approaches predicting the s± pairing state, in which the SC gap shows an s-wave symmetry that changes sign between different Fermi-surface (FS sheets. The first one is based on the itinerant spin fluctuations promoted by FS nesting, and the second is based on the local AFM exchange couplings. We apply quasiclassical Eilenberger approach to the vortex state to calculate the cutoff parameter, ξh, at different levels of impurity scattering rates and to compare results with experimental data for iron pnictides. The s±-wave pairing symmetry is considered as a presumable state for these materials. Magnetic field dependence of ξh/ξc2 is found to be nonuniversal for s± pairing: depending on the chosen parameter set it can reside both below and above analytical Ginzburg-Landau curve. It is also found that normalized ξ2/ξc2(B/Bc2 dependence is increasing with pair-breaking (interband impurity scattering, and the intraband scattering results in decreasing of the ξ2/ξc2 value. Here, ξ2 is the vortex core size and ξc2 is the Ginzburg-Landau coherence length determined from the upper critical field. The ξ2/ξc2(B/Bc2 curve has a minimum at low temperatures and small scattering evolving into monotonously decreasing function at strong scattering and high temperatures.

  4. Toward a mineral physics reference model for the Moon's core.

    Science.gov (United States)

    Antonangeli, Daniele; Morard, Guillaume; Schmerr, Nicholas C; Komabayashi, Tetsuya; Krisch, Michael; Fiquet, Guillaume; Fei, Yingwei

    2015-03-31

    The physical properties of iron (Fe) at high pressure and high temperature are crucial for understanding the chemical composition, evolution, and dynamics of planetary interiors. Indeed, the inner structures of the telluric planets all share a similar layered nature: a central metallic core composed mostly of iron, surrounded by a silicate mantle, and a thin, chemically differentiated crust. To date, most studies of iron have focused on the hexagonal closed packed (hcp, or ε) phase, as ε-Fe is likely stable across the pressure and temperature conditions of Earth's core. However, at the more moderate pressures characteristic of the cores of smaller planetary bodies, such as the Moon, Mercury, or Mars, iron takes on a face-centered cubic (fcc, or γ) structure. Here we present compressional and shear wave sound velocity and density measurements of γ-Fe at high pressures and high temperatures, which are needed to develop accurate seismic models of planetary interiors. Our results indicate that the seismic velocities proposed for the Moon's inner core by a recent reanalysis of Apollo seismic data are well below those of γ-Fe. Our dataset thus provides strong constraints to seismic models of the lunar core and cores of small telluric planets. This allows us to propose a direct compositional and velocity model for the Moon's core.

  5. Reduction of vibrational interference from the iron core on HBTXIA

    International Nuclear Information System (INIS)

    Wilcock, P.D.

    1981-01-01

    The HBTXIA machine is a toroidal reversed field pinch which utilises a 1 volt second iron core. This paper looks briefly at the sources of vibration from the iron core and describes the design of a novel support system that has been installed to minimise the transmission of vibration to plasma diagnostics and other equipment during the machine pulse. Vibration measurements on the completed installation when the core is driven to saturation are reported and compared with calculations for a ground mounted core. (author)

  6. Experimental evidence of body centered cubic iron in Earth's core

    Science.gov (United States)

    Hrubiak, R.; Meng, Y.; Shen, G.

    2017-12-01

    The Earth's core is mainly composed of iron. While seismic evidence has shown a liquid outer core and a solid inner core, the crystalline nature of the solid iron at the core condition remains debated, largely due to the difficulties in experimental determination of exact polymorphs at corresponding pressure-temperature conditions. We have examined crystal structures of iron up to 220 GPa and 6000 K with x-ray diffraction using a double-sided laser heating system at HPCAT, Advanced Photon Source. The iron sample is confined in a small chamber surrounded by single crystal MgO. The laser power can be modulated together with temperature measurements. The modulated heating of iron in an MgO single crystal matrix allows for microstructure analysis during heating and after the sample is quenched. We present experimental evidence of a body-centered-cubic (BCC) iron from about 100 GPa and 3000 K to at least 220 GPa and 4000 K. The observed BCC phase may be consistent with a theoretically predicted BCC phase that is dynamically stable in similar pressure-temperature conditions [1]. We will discuss the stability region of the BCC phase and the melting curve of iron and their implications in the nature of the Earth's inner core. References: A. B. Belonoshko et al., Nat. Geosci., 1-6 (2017).

  7. Petrography, alteration and genesis of iron mineralization in Roshtkhar

    Directory of Open Access Journals (Sweden)

    Habib Biabangard

    2017-07-01

    Full Text Available Introduction Iron mineralization in Roshtkhar is located in 48 Km east of the city of Roshtkhar and south of the Khorasan Razavi province. It is geologically located in the north east of the Lut block and the Khaf-Bardeskan volcano-plutonic belt. The Khaf-Bardeskan belt is an important metallogenic province since it is a host of valuable ore deposits such as the Kuh-e-Zar Au-Spicularite, the Tanourcheh and the Khaf Iron ore deposits (Karimpour and Malekzadeh Shafaroudi, 2007. Iron and Copper mineralization in this belt are known as the hydrothermal, skarn and IOCG types (Karimpour and Malekzadeh Shafaroudi, 2007. IOCG deposits are a new type of magmatic to hydrothermal mineralization in the continental crust (Hitzman et al., 1992. Precambrian marble, Lower Paleozoic schist and metavolcanics are the oldest rocks of the area. The younger units are Oligocene conglomerate, shale and sandstone, Miocene marl and Quaternary deposits. Iron oxides and Cu sulfides are associated with igneous rocks. Fe and Cu mineralization in Roshtkhar has been subject of a few studies such as Yousefi Surani (2006. This study describes the petrography of the host rocks, ore paragenesis, alteration types, geochemistry, genesis and other features of the Fe and Cu mineralization in the Roshtkhar iron. Methods After detailed field studies and sampling, 30 thin sections and 20 polished sections that were prepared from host rocks and ores were studied by conventional petrographic and mineraloghraphic methods in the geology department of the University of Sistan and Baluchestan. 5 samples from the alteration zones were examined by XRD in the Yamagata University in Japan, and 8 samples from the less altered ones were analyzed by XRF and ICP-OES in the Kharazmi University and the Iranian mineral processing research center (IMPRC in Karaj, respectively. The XRF and ICP-OES data are presented in Table 1. Result and discussion The host rocks of the Roshtkhar Iron deposit are diorite

  8. Iron-rich Oxides at the Core-mantle Boundary

    Science.gov (United States)

    Wicks, J. K.; Jackson, J. M.; Sturhahn, W.; Bower, D. J.; Zhuravlev, K. K.; Prakapenka, V.

    2013-12-01

    Seismic observations near the base of the core-mantle boundary (CMB) have detected 5-20 km thick patches in which the seismic wave velocities are reduced by up to 30%. These ultra-low velocity zones (ULVZs) have been interpreted as aggregates of partially molten material (e.g. Williams and Garnero 1996, Hernlund and Jellinek, 2010) or as solid, iron-enriched residues (e.g. Knittle and Jeanloz, 1991; Mao et al., 2006; Wicks et al., 2010), typically based on proposed sources of velocity reduction. The stabilities of these structure types have been explored through dynamic models that have assembled a relationship between ULVZ stability and density (Hernlund and Tackley, 2007; Bower et al., 2010). Now, to constrain the chemistry and mineralogy of ULVZs, more information is needed on the relationship between density and sound velocity of candidate phases. We present the pressure-volume-temperature equation of state of (Mg0.06 57Fe0.94)O determined up to pressures of 120 GPa and temperatures of 2000 K. Volume was measured with X-ray diffraction at beamline 13-ID-D of the Advanced Photon Source (APS), where high pressures and temperatures are achieved in a diamond anvil cell with in-situ laser heating. Sample assemblies were prepared using dehydrated NaCl as an insulator and neon as a pressure transmitting medium. We present results with and without iron as a buffer and thermal pressure gauge. We have also determined the room temperature Debye velocity (VD) of (Mg0.06 57Fe0.94)O using nuclear resonant inelastic x-ray scattering and in-situ X-ray diffraction, up to 80 GPa at 3-ID-B of the APS. The effect of the electronic environment of the iron sites on the velocities was tracked in-situ using synchrotron Moessbauer spectroscopy. Using our measured equation of state, the seismically relevant compressional (VP) and shear (VS) wave velocities were calculated from the Debye velocities. We combine these studies with a simple mixing model to predict the properties of a solid

  9. Biogenic iron mineralization at Iron Mountain, CA with implications for detection with the Mars Curiosity rover

    Science.gov (United States)

    Williams, Amy J.; Sumner, Dawn Y.; Alpers, Charles N.; Campbell, Kate M.; Nordstrom, D. Kirk

    2014-01-01

    (Introduction) Microbe-mineral interactions and biosignature preservation in oxidized sulfidic ore bodies (gossans) are prime candidates for astrobiological study. Such oxidized iron systems have been proposed as analogs for some Martian environments. Recent studies identified microbial fossils preserved as mineral-coated filaments. This study documents microbially-mediated mineral biosignatures in hydrous ferric oxide (HFO) and ferric oxyhydroxysulfates (FOHS) in three environments at Iron Mountain, CA. We investigated microbial community preservation via HFO and FOHS precipitation and the formation of filamentous mineral biosignatures. These environments included 1) actively precipitating (1000's yrs), naturally weathered HFO from in situ gossan, and 3) remobilized iron deposits, which contained lithified clastics and zones of HFO precipitate. We used published biogenicity criteria as guidelines to characterize the biogenicity of mineral filaments. These criteria included A) an actively precipitating environment where microbes are known to be coated in minerals, B) presence of extant microbial communities with carbon signatures, C) structures observable as a part of the host rock, and D) biological morphology, including cellular lumina, multiple member population, numerous taxa, variable and 3-D preservation, biological size ranges, uniform diameter, and evidence of flexibility. This study explores the relevance and detection of these biosignatures to possible Martian biosignatures. Similar filamentous biosignatures are resolvable by the Mars Hand Lens Imager (MAHLI) onboard the Mars Science Laboratory (MSL) rover, Curiosity, and may be identifiable as biogenic if present on Mars.

  10. Iron

    Science.gov (United States)

    Iron is a mineral that our bodies need for many functions. For example, iron is part of hemoglobin, a protein which carries ... It helps our muscles store and use oxygen. Iron is also part of many other proteins and ...

  11. Physicochemical characterization of mineral (iron/zinc) bound caseinate and their mineral uptake in Caco-2 cells.

    Science.gov (United States)

    Shilpashree, B G; Arora, Sumit; Kapila, Suman; Sharma, Vivek

    2018-08-15

    Milk proteins (especially caseins) are widely accepted as good vehicle for the delivery of various bioactive compounds including minerals. Succinylation is one of the most acceptable chemical modification techniques to enhance the mineral binding ability of caseins. Addition of minerals to succinylated proteins may alter their physicochemical and biochemical properties. Physicochemical characteristics of succinylated sodium caseinate (S.NaCN)-mineral (iron/zinc) complexes were elucidated. Chromatographic behaviour and fluorescence intensity confirmed the structural modification of S.NaCN upon binding with minerals. The bound mineral from protein complexes showed significantly higher (P < 0.05) in vitro bioavailability (mineral uptake) than mineral salts in Caco-2 cells. Also, iron bound S.NaCN showed higher cellular ferritin formation than iron in its free form. These mineral bound protein complexes with improved bioavailability could safely replace inorganic fortificants in various functional food formulations. Copyright © 2018 Elsevier Ltd. All rights reserved.

  12. Iron minerals formed by dissimilatory iron-and sulfur reducing bacteria studied by Moessbauer spectrometry

    International Nuclear Information System (INIS)

    Chistyakova, N. I.; Rusakov, V. S.; Nazarova, K. A.; Koksharov, Yu. A.; Zavarzina, D. G.; Greneche, J.-M.

    2008-01-01

    Zero-field and in-field Moessbauer investigations and electron paramagnetic resonance (EPR) measurements to follow the kinetics of the iron mineral formation by thermophilic dissimilatory anaerobic Fe(III)-reducing bacteria (strain Z-0001) and anaerobic alkaliphilic bacteria (strain Z-0531) were carried out.

  13. Polymorphic Nature of Iron and Degree of Lattice Preferred Orientation Beneath the Earth's Inner Core Boundary

    Science.gov (United States)

    Mattesini, Maurizio; Belonoshko, Anatoly B.; Tkalčić, Hrvoje

    2018-01-01

    Deciphering the polymorphic nature and the degree of iron lattice-preferred orientation in the Earth's inner core holds a key to understanding the present status and evolution of the inner core. A multiphase lattice-preferred orientation pattern is obtained for the top 350 km of the inner core by means of the ab initio based Candy Wrapper Velocity Model coupled to a Monte Carlo phase discrimination scheme. The achieved geographic distribution of lattice alignment is characterized by two regions of freezing, namely within South America and the Western Central Pacific, that exhibit an uncommon high degree of lattice orientation. In contrast, widespread regions of melting of relatively weak lattice ordering permeate the rest of the inner core. The obtained multiphase lattice-preferred orientation pattern is in line with mantle-constrained geodynamo simulations and allows to setup an ad hoc mineral physics scenario for the complex Earth's inner core. It is found that the cubic phase of iron is the dominating iron polymorph in the outermost part of the inner core.

  14. High Resolution Mineral Mapping of the Oman Drilling Project Cores with Imaging Spectroscopy: Preliminary Results

    Science.gov (United States)

    Greenberger, R. N.; Ehlmann, B. L.; Kelemen, P. B.; Manning, C. E.; Teagle, D. A. H.; Harris, M.; Michibayashi, K.; Takazawa, E.

    2017-12-01

    The Oman Drilling Project provides an unprecedented opportunity to study the formation and alteration of oceanic crust and peridotite. Key to answering the main questions of the project are a characterization of the primary and secondary minerals present within the drill core and their spatial relationships. To that end, we used the Caltech imaging spectrometer system to scan the entire 1.5-km archive half of the core from all four gabbro and listvenite boreholes (GT1A, GT2A, GT3A, and BT1B) at 250 µm/pixel aboard the JAMSTEC Drilling Vessel Chikyu during the ChikyuOman core description campaign. The instrument measures the visible and shortwave infrared reflectance spectra of the rocks as a function of wavelength from 0.4 to 2.6 µm. This wavelength range is sensitive to many mineral groups, including hydrated minerals (phyllosilicates, zeolites, amorphous silica polytypes), carbonates, sulfates, and transition metals, most commonly iron-bearing mineralogies. To complete the measurements, the core was illuminated with a halogen light source and moved below the spectrometer at 1 cm/s by the Chikyu's Geotek track. Data are corrected and processed to reflectance using measurements of dark current and a spectralon calibration panel. The data provide a unique view of the mineralogy at high spatial resolution. Analysis of the images for complete downhole trends is ongoing. Thus far, a variety of minerals have been identified within their petrologic contexts, including but not limited to magnesite, dolomite, calcite, quartz (through an Si-OH absorption due to minor H2O), serpentine, chlorite, epidote, zeolites, mica (fuchsite), kaolinite, prehnite, gypsum, amphibole, and iron oxides. Further analysis will likely identify more minerals. Results include rapidly distinguishing the cations present within carbonate minerals and identifying minerals of volumetrically-low abundance within the matrix and veins of core samples. This technique, for example, accurately identifies

  15. Radium Adsorption to Iron Bearing Minerals in Variable Salinity Waters

    Science.gov (United States)

    Chen, M.; Kocar, B. D.

    2014-12-01

    Radium is a common, naturally occurring radioactive metal found in many subsurface environments. Radium isotopes are a product of natural uranium and thorium decay, and are particularly abundant within groundwaters where minimal flux leads to accumulation within porewaters. Radium has been used as a natural tracer to estimate submarine groundwater discharge (SGD) [1], where the ratios of various radium isotopes are used to estimate total groundwater flux to and from the ocean [2]. Further, it represents a substantial hazard in waste water produced after hydraulic fracturing for natural gas extraction [3], resulting in a significant risk of environmental release and increased cost for water treatment or disposal. Adsorption to mineral surfaces represents a primary pathway of radium retention within subsurface environments. For SGD studies, it is important to understand adsorption processes to correctly estimate GW fluxes, while in hydraulic fracturing, radium adsorption to aquifer solids will mediate the activities of radium within produced water. While some studies of radium adsorption to various minerals have been performed [4], there is a limited understanding of the surface chemistry of radium adsorption, particularly to iron-bearing minerals such as pyrite, goethite and ferrihydrite. Accordingly, we present the results of sorption experiments of radium to a suite of iron-bearing minerals representative of those found within deep saline and near-surface (freshwater) aquifers, and evaluate impacts of varying salinity solutions through the use of artificial groundwater, seawater, and shale formation brine. Further, we explore the impacts of pyrite oxidation and ferrihydrite transformation to other iron-bearing secondary minerals on the retention of radium. This work lays the groundwork for further study of radium use as a tracer for SGD, as well as understanding mechanisms of radium retention and release from deep aquifer materials following hydraulic fracturing

  16. Iron-carbonate interaction at Earth's core-mantle boundary

    Science.gov (United States)

    Dorfman, S. M.; Badro, J.; Nabiei, F.; Prakapenka, V.; Gillet, P.

    2015-12-01

    Carbon storage and flux in the deep Earth are moderated by oxygen fugacity and interactions with iron-bearing phases. The amount of carbon stored in Earth's mantle versus the core depends on carbon-iron chemistry at the core-mantle boundary. Oxidized carbonates subducted from Earth's surface to the lowermost mantle may encounter reduced Fe0 metal from disproportionation of Fe2+ in lower mantle silicates or mixing with the core. To understand the fate of carbonates in the lowermost mantle, we have performed experiments on sandwiches of single-crystal (Ca0.6Mg0.4)CO3 dolomite and Fe foil in the laser-heated diamond anvil cell at lower mantle conditions of 49-110 GPa and 1800-2500 K. Syntheses were conducted with in situ synchrotron X-ray diffraction to identify phase assemblages. After quench to ambient conditions, samples were sectioned with a focused Ga+ ion beam for composition analysis with transmission electron microscopy. At the centers of the heated spots, iron melted and reacted completely with the carbonate to form magnesiowüstite, iron carbide, diamond, magnesium-rich carbonate and calcium carbonate. In samples heated at 49 and 64 GPa, the two carbonates exhibit a eutectoid texture. In the sample heated at 110 GPa, the carbonates form rounded ~150-nm-diameter grains with a higher modal proportion of interspersed diamonds. The presence of reduced iron in the deep lower mantle and core-mantle boundary region will promote the formation of diamonds in carbonate-bearing subducted slabs. The complete reaction of metallic iron to oxides and carbides in the presence of mantle carbonate supports the formation of these phases at the Earth's core-mantle boundary and in ultra-low velocity zones.

  17. Red Dawn: Characterizing Iron Oxide Minerals in Atmospheric Dust

    Science.gov (United States)

    Yauk, K.; Ottenfeld, C. F.; Reynolds, R. L.; Goldstein, H.; Cattle, S.; Berquo, T. S.; Moskowitz, B. M.

    2012-12-01

    Atmospheric dust is comprised of many components including small amounts of iron oxide minerals. Although the iron oxides make up a small weight percent of the bulk dust, they are important because of their roles in ocean fertilization, controls on climate, and as a potential health hazard to humans. Here we report on the iron oxide mineralogy in dust from a large dust storm, dubbed Red Dawn, which engulfed eastern Australia along a 3000 km front on 23 September 2009. Red Dawn originated from the lower Lake Eyre Basin of South Australia, western New South Wales (NSW) and southwestern Queensland and was the worst dust storm to have hit the city of Sydney in more than 60 years. Dust samples were collected from various locations across eastern Australia (Lake Cowal, Orange, Hornsby, Sydney) following the Red Dawn event. Our dust collection provides a good opportunity to study the physical and mineralogical properties of iron oxides from Red Dawn using a combination of reflectance spectroscopy, Mössbauer spectroscopy (MB), and magnetic measurements. Magnetization measurements from 20-400 K reveal that magnetite/maghemite, hematite and goethite are present in all samples with magnetite occurring in trace amounts (effects (d< 100 nm). Finally, we compared reflectance with a magnetic parameter (hard isothermal remanent magnetization, HIRM) for ferric oxide abundance to assess the degree to which ferric oxide in these samples might absorb solar radiation. In samples for which both parameters were obtained, HIRM and average reflectance over the visible wavelengths are correlated as a group (r2=0.24). These results indicate that the ferric oxide minerals in Red Dawn dust absorb solar radiation. Much of this ferric oxide occurs likely as grain coatings of nanohematite and nanogoethite, thereby providing high surface area to enhance absorption of solar radiation.

  18. The Moessbauer effect used to study iron minerals in Brazil

    International Nuclear Information System (INIS)

    Kunrath, J.I.

    1975-01-01

    The Moessbauer effect in Fe 57 was used to study iron minerals in Brazil. More than 50 samples were analyzed in this preliminary work. Although many minerals present complex spectra, it was possible to find a number of samples with relatively pure natural materials, which may be considered representative of the simple compounds that enter as constituents in the more complex cases. Important and, in some cases, drastic differences were found between spectra at room and liquid nitrogen temperatures. These differences are reported and in some cases explained. Another feature was the difference in the Moessbauer effect spectra, observable when some crystallization water is present. This phenomenon is correlated to the previous one. The methodology of this study is also reported [pt

  19. Bacterial and iron oxide aggregates mediate secondary iron mineral formation: green rust versus magnetite.

    Science.gov (United States)

    Zegeye, A; Mustin, C; Jorand, F

    2010-06-01

    In the presence of methanoate as electron donor, Shewanella putrefaciens, a Gram-negative, facultative anaerobe, is able to transform lepidocrocite (gamma-FeOOH) to secondary Fe (II-III) minerals such as carbonated green rust (GR1) and magnetite. When bacterial cells were added to a gamma-FeOOH suspension, aggregates were produced consisting of both bacteria and gamma-FeOOH particles. Recently, we showed that the production of secondary minerals (GR1 vs. magnetite) was dependent on bacterial cell density and not only on iron reduction rates. Thus, gamma-FeOOH and S. putrefaciens aggregation pattern was suggested as the main mechanism driving mineralization. In this study, lepidocrocite bioreduction experiments, in the presence of anthraquinone disulfonate, were conducted by varying the [cell]/[lepidocrocite] ratio in order to determine whether different types of aggregate are formed, which may facilitate precipitation of GR1 as opposed to magnetite. Confocal laser scanning microscopy was used to analyze the relative cell surface area and lepidocrocite concentration within the aggregates and captured images were characterized by statistical methods for spatial data (i.e. variograms). These results suggest that the [cell]/[lepidocrocite] ratio influenced both the aggregate structure and the nature of the secondary iron mineral formed. Subsequently, a [cell]/[lepidocrocite] ratio above 1 x 10(7) cells mmol(-1) leads to densely packed aggregates and to the formation of GR1. Below this ratio, looser aggregates are formed and magnetite was systematically produced. The data presented in this study bring us closer to a more comprehensive understanding of the parameters governing the formation of minerals in dense bacterial suspensions and suggest that screening mineral-bacteria aggregate structure is critical to understanding (bio)mineralization pathways.

  20. Direct measurement of thermal conductivity in solid iron at planetary core conditions.

    Science.gov (United States)

    Konôpková, Zuzana; McWilliams, R Stewart; Gómez-Pérez, Natalia; Goncharov, Alexander F

    2016-06-02

    The conduction of heat through minerals and melts at extreme pressures and temperatures is of central importance to the evolution and dynamics of planets. In the cooling Earth's core, the thermal conductivity of iron alloys defines the adiabatic heat flux and therefore the thermal and compositional energy available to support the production of Earth's magnetic field via dynamo action. Attempts to describe thermal transport in Earth's core have been problematic, with predictions of high thermal conductivity at odds with traditional geophysical models and direct evidence for a primordial magnetic field in the rock record. Measurements of core heat transport are needed to resolve this difference. Here we present direct measurements of the thermal conductivity of solid iron at pressure and temperature conditions relevant to the cores of Mercury-sized to Earth-sized planets, using a dynamically laser-heated diamond-anvil cell. Our measurements place the thermal conductivity of Earth's core near the low end of previous estimates, at 18-44 watts per metre per kelvin. The result is in agreement with palaeomagnetic measurements indicating that Earth's geodynamo has persisted since the beginning of Earth's history, and allows for a solid inner core as old as the dynamo.

  1. Controls on radium transport by adsorption to iron minerals

    Science.gov (United States)

    Chen, M.; Wang, T.; Kocar, B. D.

    2015-12-01

    Radium is a naturally occurring radioactive metal found in many subsurface environments. Radium isotopes are generated by uranium and thorium decay, and are particularly abundant within groundwaters where minimal porewater flux leads to accumulation. These isotopes are used as natural tracers for estimating submarine groundwater discharge (SGD) [1], allowing for large scale estimation of GW fluxes into and out of the ocean [2]. They also represent a substantial hazard in wastewater produced after hydraulic fracturing for natural gas extraction [3], resulting in a significant risk of environmental release to surface and near-surface waters, and increased cost for water treatment or disposal. Adsorption to mineral surfaces represents a dominant pathway of radium retention in subsurface environments. For SGD studies, adsorption processes impact estimates of GW fluxes, while in hydraulic fracturing, radium adsorption to aquifer solids mediates wastewater radium activities. Analysis of past sorption studies revealed large variability in partition coefficients [4], while examination of radium adsorption kinetics and surface complexation have only recently started [5]. Accordingly, we present the results of sorption and column experiments of radium with a suite of iron minerals representative of those found within deep saline and near-surface (freshwater) aquifers, and evaluate impacts of varying salinity solutions through artificial waters. Further, we explore the impacts of pyrite oxidation and ferrihydrite transformation to other iron-bearing secondary minerals on the transport and retention of radium. These results will provide critical information on the mineralogical controls on radium retention in subsurface environments, and will therefore improve predictions of radium groundwater transport in natural and contaminated systems. [1] Charette, M.A., Buesseler, K.O. & Andrews, J.E., Limnol. Oceanogr. (2001). [2] Moore, W.S., Ann. Rev. Mar. Sci. (2010). [3] Vengosh, A

  2. Structural and magnetic properties of core-shell iron-iron oxide nanoparticles

    DEFF Research Database (Denmark)

    Kuhn, Luise Theil; Bojesen, A.; Timmermann, L.

    2002-01-01

    We present studies of the structural and magnetic properties of core-shell iron-iron oxide nanoparticles. alpha-Fe nanoparticles were fabricated by sputtering and subsequently covered with a protective nanocrystalline oxide shell consisting of either maghaemite (gamma-Fe2O3) or partially oxidized...... magnetite (Fe3O4). We observed that the nanoparticles were stable against further oxidation, and Mossbauer spectroscopy at high applied magnetic fields and low temperatures revealed a stable form of partly oxidized magnetite. The nanocrystalline structure of the oxide shell results in strong canting...... of the spin structure in the oxide shell, which thereby modifies the magnetic properties of the core-shell nanoparticles....

  3. Rotating collapse of stellar iron cores in general relativity

    International Nuclear Information System (INIS)

    Ott, C D; Dimmelmeier, H; Marek, A; Janka, H-T; Zink, B; Hawke, I; Schnetter, E

    2007-01-01

    We present results from the first 2 + 1 and 3 + 1 simulations of the collapse of rotating stellar iron cores in general relativity employing a finite-temperature equation of state and an approximate treatment of deleptonization during collapse. We compare full 3 + 1 and conformally-flat spacetime evolution methods and find that the conformally-flat treatment is sufficiently accurate for the core-collapse supernova problem. We focus on the gravitational wave (GW) emission from rotating collapse, core bounce and early postbounce phases. Our results indicate that the GW signature of these phases is much more generic than previously estimated. In addition, we track the growth of a nonaxisymmetric instability of dominant m = 1 character in two of our models that leads to prolonged narrow-band GW emission at ∼920-930 Hz over several tens of milliseconds

  4. What do we really know about the role of microorganisms in iron sulfide mineral formation?

    Science.gov (United States)

    Picard, Aude A.; Gartman, Amy; Girguis, Peter R.

    2016-01-01

    Iron sulfide mineralization in low-temperature systems is a result of biotic and abiotic processes, though the delineation between these two modes of formation is not always straightforward. Here we review the role of microorganisms in the precipitation of extracellular iron sulfide minerals. We summarize the evidence that links sulfur-metabolizing microorganisms and sulfide minerals in nature and we present a critical overview of laboratory-based studies of the nucleation and growth of iron sulfide minerals in microbial cultures. We discuss whether biologically derived minerals are distinguishable from abiotic minerals, possessing attributes that are uniquely diagnostic of biomineralization. These inquiries have revealed the need for additional thorough, mechanistic and high-resolution studies to understand microbially mediated formation of a variety of sulfide minerals across a range of natural environments.

  5. Minerals

    Science.gov (United States)

    ... Aren't minerals something you find in the earth, like iron and quartz? Well, yes, but small ... canned salmon and sardines with bones leafy green vegetables, such as broccoli calcium-fortified foods — from orange ...

  6. The end of the iron-core age.

    Science.gov (United States)

    Lyttleton, R. A.

    1973-01-01

    The terrestrial planets aggregated essentially from small particles, to begin as solid cool bodies with the same general compositions, and there is no possibility of an iron-core developing within any of them at any stage. Their differing internal and surface properties receive ready explanation from their different masses which determine whether the pressures within are sufficient to bring about phase-changes. The claim that the terrestrial core can be identified by means of shock-wave data as nickel-iron is based on theoretical misconception, whereas the actual seismic data establish an uncompressed-density value much lower than any such mixture could have. The onset of the Ramsey phase-change in the earth takes the form of a rapid initial collapse to produce a large core in metallic state which thereafter continues to grow secularly as a result of radioactive heating and leads to reduction of surface-area at long last adequate to account for folded and thrusted mountain-building.

  7. Plasma current sustainment after iron core saturation in the STOR-M tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Mitarai, O., E-mail: omitarai@ktmail.tokai-u.jp [Kumamoto Liberal Arts Education Center, Tokai University, 9-1-1 Toroku, Higashi-ku, Kumamoto 862-8652 (Japan); Ding, Y.; Hubeny, M.; Lu, Y.; Onchi, T.; McColl, D.; Xiao, C.; Hirose, A. [Plasma Physics Laboratory, University of Saskatchewan, 116 Science Place, Saskatoon, SK S7N 5E2 (Canada)

    2014-10-15

    Highlights: • Plasma current can be started up by small iron core without central solenoid. • Iron core removes central solenoid. • Plasma current can be maintained after iron core saturation. • Hysteresis curve shows the partial core saturation. • Image field from iron core is estimated during discharge. • Spherical tokamak reactor without CS is proposed using the small iron core. - Abstract: We propose to use of a small iron core transformer to start up the plasma current in a spherical tokamak (ST) reactor without central solenoid (CS). Taking advantage of the high aspect ratio of the STOR-M iron core tokamak, we have demonstrated that the plasma current up to 10–15 kA can be started up using the outer Ohmic heating (OH) coils without CS, and that the plasma current can be maintained further by increasing the outer OH coil current during iron core saturation phase. When the magnetizing current reaches 1.2 kA and the iron core becomes saturated, the third capacitor bank connected to the outer OH coils is discharged to maintain the plasma current. The plasma current is slightly increased and maintained for additional 5 ms as expected from numerical calculations. Core saturation has been clearly observed on the hysteresis curve. This is the first experimental demonstration of the feasibility of slow transition from the iron core to air core transformer phase without CS. The results implies that a plasma current can be initiated by a small iron core and could be ramped up by additional heating and vertical field after iron core saturation in future STs without CS.

  8. Iron/iron oxide core-shell nanoclusters for biomedical applications

    International Nuclear Information System (INIS)

    Qiang You; Antony, Jiji; Sharma, Amit; Nutting, Joseph; Sikes, Daniel; Meyer, Daniel

    2006-01-01

    Biocompatible magnetic nanoparticles have been found promising in several biomedical applications for tagging, imaging, sensing and separation in recent years. Most magnetic particles or beads currently used in biomedical applications are based on ferromagnetic iron oxides with very low specific magnetic moments of about 20-30 emu/g. Here we report a new approach to synthesize monodispersed core-shell nanostructured clusters with high specific magnetic moments above 200 emu/g. Iron nanoclusters with monodispersive size of diameters from 2 nm to 100 nm are produced by our newly developed nanocluster source and go to a deposition chamber, where a chemical reaction starts, and the nanoclusters are coated with iron oxides. HRTEM Images show the coatings are very uniform and stable. The core-shell nanoclusters are superparamagnetic at room temperature for sizes less than 15 nm, and then become ferromagnetic when the cluster size increases. The specific magnetic moment of core-shell nanoclusters is size dependent, and increases rapidly from about 80 emu/g at the cluster size of around 3 nm to over 200 emu/g up to the size of 100 nm. The use of high magnetic moment nanoclusters for biomedical applications could dramatically enhance the contrast for MRI, reduce the concentration of magnetic particle needs for cell separation, or make drug delivery possible with much lower magnetic field gradients

  9. All Metal Iron Core For A Low Aspect Ratio Tokamak

    International Nuclear Information System (INIS)

    Gates, D.A.; Jun, C.; Zatz, I.; Zolfaghari, A.

    2010-01-01

    A novel concept for incorporating a iron core transformer within a axisymmetric toroidal plasma containment device with a high neutron flux is described. This design enables conceptual design of low aspect ratio devices which employ standard transformer-driven plasma startup by using all-metal high resistance separators between the toroidal field windings. This design avoids the inherent problems of a multiturn air core transformer which will inevitably suffer from strong neutron bombardment and hence lose the integrity of its insulation, both through long term material degradation and short term neutron-induced conductivity. A full 3-dimensional model of the concept has been developed within the MAXWELL program and the resultant loop voltage calculated. The utility of the result is found to be dependent on the resistivity of the high resistance separators. Useful loop voltage time histories have been obtained using achievable resistivities.

  10. Magnetization measurements and XMCD studies on ion irradiated iron oxide and core-shell iron/iron-oxide nanomaterials

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, Maninder; Qiang, You; Jiang, Weilin; Pearce, Carolyn; McCloy, John S.

    2014-12-02

    Magnetite (Fe3O4) and core-shell iron/iron-oxide (Fe/Fe3O4) nanomaterials prepared by a cluster deposition system were irradiated with 5.5 MeV Si2+ ions and the structures determined by x-ray diffraction as consisting of 100% magnetite and 36/64 wt% Fe/FeO, respectively. However, x-ray magnetic circular dichroism (XMCD) indicates similar surfaces in the two samples, slightly oxidized and so having more Fe3+ than the expected magnetite structure, with XMCD intensity much lower for the irradiated core-shell samples indicating weaker magnetism. X-ray absorption spectroscopy (XAS) data lack the signature for FeO, but the irradiated core-shell system consists of Fe-cores with ~13 nm of separating oxide crystallite, so it is likely that FeO exists deeper than the probe depth of the XAS (~5 nm). Exchange bias (Hex) for both samples becomes increasingly negative as temperature is lowered, but the irradiated Fe3O4 sample shows greater sensitivity of cooling field on Hex. Loop asymmetries and Hex sensitivities of the irradiated Fe3O4 sample are due to interfaces and interactions between grains which were not present in samples before irradiation as well as surface oxidation. Asymmetries in the hysteresis curves of the irradiated core/shell sample are related to the reversal mechanism of the antiferromagnetic FeO and possibly some near surface oxidation.

  11. Equilibrium and stability studies for an iron-core tokamak with a poloidal divertor

    International Nuclear Information System (INIS)

    Solano, E.R.; Neilson, G.H.; Lao, L.L.

    1989-01-01

    A study of plasma equilibrium and stability in a tokamak with an unsaturated iron core is presented. A spool model is developed for the iron. Both, a simplified force balance code and a Grad-Shafranov solver are used to study the plasma equilibrium. It is observed that the iron can strongly modify the conditions for equilibrium and stability, and in some cases an infinite cylinder model for the iron core is not adequate. New criteria for plasma position stability in the presence of an iron core are introduced. 17 refs., 4 figs., 3 tabs

  12. First order study for an iron core OH system for TNS

    International Nuclear Information System (INIS)

    Ballou, J.K.; Schultz, J.

    1977-01-01

    A simple comparison has been made between an air core and an iron core ohmic heating system for a particular device, and it was shown that the peak power requirements can be substantially reduced by the use of an iron core to power levels handled by industry today. It was also shown that for an ohmic heating system initiated plasma that the cost of the iron core ohmic heating power system (iron core, dual rectifier, and DC switch) is less than the cost for a subset of the power system for an air core system (dual rectifier and DC switch). There is considerable work being done on other methods of initiating the plasma none of which seem to be incompatible with the use of an iron core system

  13. A novel approach to linearization of the electromagnetic parameters of tokamaks with an iron core

    Energy Technology Data Exchange (ETDEWEB)

    Fu, P. E-mail: fupeng@mail.ipp.ac.cn; Liu, Z.Z.; Zou, J.H

    2002-05-01

    The equivalent model of an iron core tokamak is developed, in which the electromagnetic parameters of several pairs of coils in opposite series (PCOS) are not dependent on the saturation of the iron core during tokamak operation. With this the electromagnetic parameters of all the coils in an iron core tokamak can be linearized, As an example, the electromagnetic parameters of Hefei Super-conductive Tokamak with iron core (HT-7) are linearized, and it is in good agreement with the experimental results. The linearization approach can be applied in real time plasma control and electromagnetic analysis.

  14. Atmospheric processing of iron carried by mineral dust

    Directory of Open Access Journals (Sweden)

    S. Nickovic

    2013-09-01

    Full Text Available Nutrification of the open ocean originates mainly from deposited aerosol in which the bio-avaliable iron is likely to be an important factor. The relatively insoluble iron in dust from arid soils becomes more soluble after atmospheric processing and, through its deposition in the ocean, could contribute to marine primary production. To numerically simulate the atmospheric route of iron from desert sources to sinks in the ocean, we developed a regional atmospheric dust-iron model that included parameterization of the transformation of iron to a soluble form caused by dust mineralogy, cloud processes and solar radiation. When compared with field data on the aerosol iron, which were collected during several Atlantic cruises, the results from the higher-resolution simulation experiments showed that the model was capable of reproducing the major observed patterns.

  15. Mineral resource of the month: Iron and steel

    Science.gov (United States)

    Fenton, Michael D.

    2014-01-01

    Iron is one of the most abundant elements on Earth, but it does not occur in nature in a useful metallic form. Although ancient people may have recovered some iron from meteorites, it wasn’t until smelting was invented that iron metal could be derived from iron oxides. After the beginning of the Iron Age in about 1200 B.C., knowledge of iron- and steelmaking spread from the ancient Middle East through Greece to the Roman Empire, then to Europe and, in the early 17th century, to North America. The first successful furnace in North America began operating in 1646 in what is now Saugus, Mass. Introduction of the Bessemer converter in the mid-19th century made the modern steel age possible.

  16. Liquid-Liquid Extraction and Determination of Trace Elements in Iron Minerals by Atomic Absorption Spectrometry

    International Nuclear Information System (INIS)

    Taseska, Milena; Stafilov, Trajche; Makreski, Petre; Jacimovic, Radojko; Jovanovski, Gligor

    2006-01-01

    Various trace elements (cadmium, chromium, cobalt, nickel, manganese) in some iron minerals were determined by flame (FAAS) and electrothermal atomic absorption spectrometry (ETAAS). The studied minerals were chalcopyrite (CuFeS 2 ), hematite (Fe 2 O 3 ) and pyrite (FeS 2 ). To avoid the interference of iron, a method for liquid-liquid extraction of iron and determination of investigated elements in the inorganic phase was proposed. Iron was extracted by diisopropyl ether in hydrochloride acid solution and the extraction method was optimized. Some parameters were obtained to be significantly important: Fe mass in the sample should not exceed 0.3 g, the optimal concentration of HCI should be 7.8 mol 1 -1 and ratio of the inorganic and organic phase should be 1: 1. The procedure was verified by the method of standard additions and by its applications to reference standard samples. The investigated minerals originate from various mines in the Republic of Macedonia. (Author)

  17. Sedimentary and mineral dust sources of dissolved iron to the world ocean

    Directory of Open Access Journals (Sweden)

    J. K. Moore

    2008-05-01

    Full Text Available Analysis of a global compilation of dissolved-iron observations provides insights into the processes controlling iron distributions and some constraints for ocean biogeochemical models. The distribution of dissolved iron appears consistent with the conceptual model developed for Th isotopes, whereby particle scavenging is a two-step process of scavenging mainly by colloidal and small particulates, followed by aggregation and removal on larger sinking particles. Much of the dissolved iron (<0.4 μm is present as small colloids (>~0.02 μm and, thus, is subject to aggregation and scavenging removal. This implies distinct scavenging regimes for dissolved iron consistent with the observations: 1 a high scavenging regime – where dissolved-iron concentrations exceed the concentrations of strongly binding organic ligands; and 2 a moderate scavenging regime – where dissolved iron is bound to both colloidal and soluble ligands. Within the moderate scavenging regime, biological uptake and particle scavenging decrease surface iron concentrations to low levels (<0.2 nM over a wide range of low to moderate iron input levels. Removal rates are also highly nonlinear in areas with higher iron inputs. Thus, observed surface-iron concentrations exhibit a bi-modal distribution and are a poor proxy for iron input rates. Our results suggest that there is substantial removal of dissolved iron from subsurface waters (where iron concentrations are often well below 0.6 nM, most likely due to aggregation and removal on sinking particles of Fe bound to organic colloids.

    We use the observational database to improve simulation of the iron cycle within a global-scale, Biogeochemical Elemental Cycling (BEC ocean model. Modifications to the model include: 1 an improved particle scavenging parameterization, based on the sinking mass flux of particulate organic material, biogenic silica, calcium carbonate, and mineral dust particles; 2 desorption of dissolved iron

  18. Influence of iron redox cycling on organo-mineral associations in arctic tundra soils

    Science.gov (United States)

    Herndon, E.; AlBashaireh, A.; Duroe, K.; Singer, D. M.

    2016-12-01

    Geochemical interactions between soil organic matter and minerals influence decomposition in many environments but remain poorly understood in arctic tundra systems. In tundra soils that are periodically to persistently saturated, the accumulation of iron oxyhydroxides and organo-iron precipitates at redox interfaces may inhibit decomposition by binding organic molecules and protecting them from microbial degradation. Here, we couple synchrotron-source spectroscopic techniques with chemical sequential extractions and physical density fractionations to evaluate the spatial distribution and speciation of Fe-bearing phases and associated organic matter in organic and mineral horizons of the seasonally thawed active layer in tundra soils from northern Alaska. Mineral-associated organic matter comprised 63 ± 9% of soil organic carbon stored in the active layer of ice wedge polygons. Ferrous iron produced in anoxic mineral horizons diffused upwards and precipitated as poorly-crystalline oxyhydroxides and organic-bound Fe(III) in the organic horizons. Ferrihydrite and goethite were present as coatings on mineral grains and plant debris and in aggregates with clays and particulate organic matter. Organic matter released through acid-dissolution of iron oxides may represent a small pool of readily-degradable organic molecules temporarily stabilized by sorption to iron oxyhydroxide surfaces, while larger quantities of particulate organic carbon and humic-like substances may be physically protected from decomposition by Fe-oxide coatings and aggregation. We conclude that formation of poorly-crystalline and crystalline iron oxides at redox interfaces contributes to mineral protection of organic matter through sorption, aggregation, and co-precipitation reactions. Further study of organo-mineral associations is necessary to determine the net impact of mineral-stabilization on carbon storage in rapidly warming arctic ecosystems.

  19. Formation of iron nanoparticles and increase in iron reactivity in mineral dust during simulated cloud processing.

    Science.gov (United States)

    Shi, Zongbo; Krom, Michael D; Bonneville, Steeve; Baker, Alex R; Jickells, Timothy D; Benning, Liane G

    2009-09-01

    The formation of iron (Fe) nanoperticles and increase in Fe reactivity in mineral dust during simulated cloud processing was investigated using high-resolution microscopy and chemical extraction methods. Cloud processing of dust was experimentally simulated via an alternation of acidic (pH 2) and circumneutral conditions (pH 5-6) over periods of 24 h each on presieved (formation of Fe-rich nanoparticle aggregates, which were not found initially. Similar Fe-rich nanoparticles were also observed in wet-deposited Saharen dusts from the western Mediterranean but not in dry-deposited dust from the eastern Mediterranean. Sequential Fe extraction of the soil samples indicated an increase in the proportion of chemically reactive Fe extractable by an ascorbate solution after simulated cloud processing. In addition, the sequential extractions on the Mediterranean dust samples revealed a higher content of reactive Fe in the wet-deposited dust compared to that of the dry-deposited dust These results suggestthat large variations of pH commonly reported in aerosol and cloud waters can trigger neo-formation of nanosize Fe particles and an increase in Fe reactivity in the dust

  20. Influence of iron redox cycling on organo-mineral associations in Arctic tundra soil

    Science.gov (United States)

    Herndon, Elizabeth; AlBashaireh, Amineh; Singer, David; Roy Chowdhury, Taniya; Gu, Baohua; Graham, David

    2017-06-01

    Arctic tundra stores large quantities of soil organic matter under varying redox conditions. As the climate warms, these carbon reservoirs are susceptible to increased rates of decomposition and release to the atmosphere as the greenhouse gases carbon dioxide (CO2) and methane (CH4). Geochemical interactions between soil organic matter and minerals influence decomposition in many environments but remain poorly understood in Arctic tundra systems and are not considered in decomposition models. The accumulation of iron (Fe) oxyhydroxides and organo-iron precipitates at redox interfaces may be particularly important for carbon cycling given that ferric iron [Fe(III)] species can enhance decomposition by serving as terminal electron acceptors in anoxic soils or inhibit microbial decomposition by binding organic molecules. Here, we examine chemical properties of solid-phase Fe and organic matter in organic and mineral horizons within the seasonally thawed active layer of Arctic tundra on the North Slope of Alaska. Spectroscopic techniques, including micro-X-ray fluorescence (μXRF) mapping, micro-X-ray absorption near-edge structure (μXANES) spectroscopy, and Fourier transform infrared spectroscopy (FTIR), were coupled with chemical sequential extractions and physical density fractionations to evaluate the spatial distribution and speciation of Fe-bearing phases and associated organic matter in soils. Organic horizons were enriched in poorly crystalline and crystalline iron oxides, and approximately 60% of total Fe stored in organic horizons was calculated to derive from upward translocation from anoxic mineral horizons. Ferrihydrite and goethite were present as coatings on mineral grains and plant debris, and in aggregates with clays and particulate organic matter. Minor amounts of ferrous iron [Fe(II)] were present in iron sulfides (i.e., pyrite and greigite) in mineral horizon soils and iron phosphates (vivianite) in organic horizons. Concentrations of organic

  1. Size-Dependent Specific Surface Area of Nanoporous Film Assembled by Core-Shell Iron Nanoclusters

    Directory of Open Access Journals (Sweden)

    Jiji Antony

    2006-01-01

    Full Text Available Nanoporous films of core-shell iron nanoclusters have improved possibilities for remediation, chemical reactivity rate, and environmentally favorable reaction pathways. Conventional methods often have difficulties to yield stable monodispersed core-shell nanoparticles. We produced core-shell nanoclusters by a cluster source that utilizes combination of Fe target sputtering along with gas aggregations in an inert atmosphere at 7∘C. Sizes of core-shell iron-iron oxide nanoclusters are observed with transmission electron microscopy (TEM. The specific surface areas of the porous films obtained from Brunauer-Emmett-Teller (BET process are size-dependent and compared with the calculated data.

  2. Iron and manganese oxide mineralization in the Pacific

    Science.gov (United States)

    Hein, J. R.; Koschinsky, A.; Halbach, P.; Manheim, F. T.; Bau, M.; Jung-Keuk, Kang; Lubick, N.

    1997-01-01

    Iron, manganese, and iron-manganese deposits occur in nearly all geomorphologic and tectonic environments in the ocean basins and form by one or more of four processes: (1) hydrogenetic precipitation from cold ambient seawater, (2) precipitation from hydrothermal fluids, (3) precipitation from sediment pore waters that have been modified from bottom water compositions by diagenetic reactions in the sediment column and (4) replacement of rocks and sediment. These processes are discussed.

  3. Arabidopsis Glutaredoxin S17 Contributes to Vegetative Growth, Mineral Accumulation, and Redox Balance during Iron Deficiency

    Directory of Open Access Journals (Sweden)

    Han Yu

    2017-06-01

    Full Text Available Iron (Fe is an essential mineral nutrient and a metal cofactor required for many proteins and enzymes involved in the processes of DNA synthesis, respiration, and photosynthesis. Iron limitation can have detrimental effects on plant growth and development. Such effects are mediated, at least in part, through the generation of reactive oxygen species (ROS. Thus, plants have evolved a complex regulatory network to respond to conditions of iron limitations. However, the mechanisms that couple iron deficiency and oxidative stress responses are not fully understood. Here, we report the discovery that an Arabidopsis thaliana monothiol glutaredoxin S17 (AtGRXS17 plays a critical role in the plants ability to respond to iron deficiency stress and maintain redox homeostasis. In a yeast expression assay, AtGRXS17 was able to suppress the iron accumulation in yeast ScGrx3/ScGrx4 mutant cells. Genetic analysis indicated that plants with reduced AtGRXS17 expression were hypersensitive to iron deficiency and showed increased iron concentrations in mature seeds. Disruption of AtGRXS17 caused plant sensitivity to exogenous oxidants and increased ROS production under iron deficiency. Addition of reduced glutathione rescued the growth and alleviates the sensitivity of atgrxs17 mutants to iron deficiency. These findings suggest AtGRXS17 helps integrate redox homeostasis and iron deficiency responses.

  4. Iron Hydroxide Minerals Drive Organic and Phosphorus Chemistry in Subsurface Redox / pH Gradients

    Science.gov (United States)

    Flores, E.; Barge, L. M.; VanderVelde, D.; Baum, M.

    2017-12-01

    Iron minerals, particularly iron oxides and oxyhydroxides, are prevalent on Mars and may exist in mixed valence or even reduced states beneath the oxidized surface. Iron (II,III) hydroxides, including green rust, are reactive and potentially catalytic minerals that can absorb and concentrate charged species, while also driving chemical reactions. These minerals are highly redox-sensitive and the presence of organics and/or phosphorus species could affect their mineralogy and/or stability. Conversely, the minerals might be able to drive chemical processes such as amino acid formation, phosphorus oxyanion reactions, or could simply selectively preserve organic species via surface adsorption. In an open aqueous sediment column, soluble products of mineral-driven reactions could also diffuse to sites of different chemical conditions to react even further. We synthesized Fe-hydroxide minerals under various conditions relevant to early Earth and ancient Mars (>3.0 Gyr), anoxically and in the presence of salts likely to have been present in surface or ground waters. Using these minerals we conducted experiments to test whether iron hydroxides could promote amino acid formation, and how the reaction is affected by subsurface gradients of redox, pH, and temperature. We also tested the adsorption of organic and phosphorus species onto Fe-hydroxide minerals at different conditions within the gradients. The suite of organic or phosphorus signatures that may be found in a particular mineral system is a combination of what is synthesized there, what is preferentially concentrated / retained there, and what is preserved against degradation. Further work is needed to determine how these processes could have proceeded on Mars and what mineral-organic signatures, abiotic or otherwise, would be produced from such processes.

  5. Binding of Pseudomonas aeruginosa Apo-Bacterioferritin Associated Ferredoxin to Bacterioferritin B Promotes Heme Mediation of Electron Delivery and Mobilization of Core Mineral Iron†

    Science.gov (United States)

    Weeratunga, Saroja K.; Gee, Casey E.; Lovell, Scott; Zeng, Yuhong; Woodin, Carrie L.; Rivera, Mario

    2009-01-01

    The bfrB gene from Pseudomonas aeruginosa was cloned and expressed in E. coli. The resultant protein (BfrB), which assembles into a 445.3 kDa complex0020from 24 identical subunits, binds 12 molecules of heme axially coordinated by two Met residues. BfrB, isolated with 5–10 iron atoms per protein molecule, was reconstituted with ferrous ions to prepare samples with a core mineral containing 600 ± 40 ferric ions per BfrB molecule and approximately one phosphate molecule per iron atom. In the presence of sodium dithionite or in the presence of P. aeruginosa ferredoxin NADP reductase (FPR) and NADPH the heme in BfrB remains oxidized and the core iron mineral is mobilized sluggishly. In stark contrast, addition of NADPH to a solution containing BfrB, FPR and the apo-form of P. aeruginosa bacterioferritin associated ferredoxin (apo-Bfd) results in rapid reduction of the heme in BfrB and in the efficient mobilization of the core iron mineral. Results from additional experimentation indicate that Bfd must bind to BfrB to promote heme mediation of electrons from the surface to the core to support the efficient mobilization of ferrous ions from BfrB. In this context, the thus far mysterious role of heme in bacterioferritins has been brought to the front by reconstituting BfrB with its physiological partner, apo-Bfd. These findings are discussed in the context of a model for the utilization of stored iron in which the significant upregulation of the bfd gene under low-iron conditions [Ochsner, U.A., Wilderman, P.J., Vasil, A.I., and Vasil, M.L. (2002) Mol. Microbiol. 45, 1277–1287] ensures sufficient concentrations of apo-Bfd to bind BfrB and unlock the iron stored in its core. Although these findings are in contrast to previous speculations suggesting redox mediation of electron transfer by holo-Bfd, the ability of apo-Bfd to promote iron mobilization is an economical strategy used by the cell because it obviates the need to further deplete cellular iron levels to

  6. Investigating the effect of ascorbate on the Fe(II)-catalyzed transformation of the poorly crystalline iron mineral ferrihydrite.

    Science.gov (United States)

    Xiao, Wei; Jones, Adele M; Collins, Richard N; Waite, T David

    2018-05-09

    The inorganic core of the iron storage protein, ferritin, is recognized as being analogous to the poorly crystalline iron mineral, ferrihydrite (Fh). Fh is also abundant in soils where it is central to the redox cycling of particular soil contaminants and trace elements. In geochemical circles, it is recognized that Fh can undergo Fe(II)-catalyzed transformation to form more crystalline iron minerals, vastly altering the reactivity of the iron oxide and, in some cases, the redox poise of the system. Of relevance to both geochemical and biological systems, we investigate here if the naturally occurring reducing agent, ascorbate, can effect such an Fe(II)-catalyzed transformation of Fh at 25 °C and circumneutral pH. The transformation of ferrihydrite to possible secondary Fe(III) mineralization products was quantified using Fourier transform infrared (FTIR) spectroscopy, with supporting data obtained using X-ray absorbance spectroscopy (XAS) and X-ray diffraction (XRD). Whilst the amount of Fe(II) formed in the presence of ascorbate has resulted in Fh transformation in previous studies, no transformation of Fh to more crystalline Fe(III) (oxyhydr)oxides was observed in this study. Further experiments indicated this was due to the ability of ascorbate to inhibit the formation of goethite, lepidocrocite and magnetite. The manner in which ascorbate associated with Fh was investigated using FTIR and total organic carbon (TOC) analysis. The majority of ascorbate was found to adsorb to the Fh surface under anoxic conditions but, under oxic conditions, ascorbate was initially adsorbed then became incorporated within the Fe(III) (oxyhydr)oxide structure (i.e., co-precipitated) over time. Copyright © 2018 Elsevier B.V. All rights reserved.

  7. Composition, speciation and distribution of iron minerals in Imperata cylindrica.

    Science.gov (United States)

    Amils, Ricardo; de la Fuente, Vicenta; Rodríguez, Nuria; Zuluaga, Javier; Menéndez, Nieves; Tornero, Jesús

    2007-05-01

    A comparative study of the roots, rhizomes and leaves of an iron hyperaccumulator plant, Imperata cylindrica, isolated from the banks of an extreme acidic environment, using complementary techniques: Mösbauer spectroscopy (MS), X-ray diffraction (XRD), scanning electron microscopy (SEM) coupled to energy-dispersive X-ray microanalysis (EDAX) and transmission electron microscopy (TEM), has shown that two main biominerals, jarosite and ferrihydrate-ferritin, accumulate in the different tissues. Jarosite accumulates mainly in roots and rhizomes, while ferritin has been detected in all the structures. A model of iron management in I. cylindrica is presented.

  8. Surface materials map of Afghanistan: iron-bearing minerals and other materials

    Science.gov (United States)

    King, Trude V.V.; Kokaly, Raymond F.; Hoefen, Todd M.; Dudek, Kathleen B.; Livo, Keith E.

    2012-01-01

    This map shows the distribution of selected iron-bearing minerals and other materials derived from analysis of HyMap imaging spectrometer data of Afghanistan. Using a NASA (National Aeronautics and Space Administration) WB-57 aircraft flown at an altitude of ~15,240 meters or ~50,000 feet, 218 flight lines of data were collected over Afghanistan between August 22 and October 2, 2007. The HyMap data were converted to apparent surface reflectance, then further empirically adjusted using ground-based reflectance measurements. The reflectance spectrum of each pixel of HyMap data was compared to the spectral features of reference entries in a spectral library of minerals, vegetation, water, ice, and snow. This map shows the spatial distribution of iron-bearing minerals and other materials having diagnostic absorptions at visible and near-infrared wavelengths. These absorptions result from electronic processes in the minerals. Several criteria, including (1) the reliability of detection and discrimination of minerals using the HyMap spectrometer data, (2) the relative abundance of minerals, and (3) the importance of particular minerals to studies of Afghanistan's natural resources, guided the selection of entries in the reference spectral library and, therefore, guided the selection of mineral classes shown on this map. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated. Minerals having similar spectral features were less easily discriminated, especially where the minerals were not particularly abundant and (or) where vegetation cover reduced the absorption strength of mineral features. Complications in reflectance calibration also affected the detection and identification of minerals.

  9. A genetic link between magnetite mineralization and diorite intrusion at the El Romeral iron oxide-apatite deposit, northern Chile

    Science.gov (United States)

    Rojas, Paula A.; Barra, Fernando; Reich, Martin; Deditius, Artur; Simon, Adam; Uribe, Francisco; Romero, Rurik; Rojo, Mario

    2018-01-01

    El Romeral is one of the largest iron oxide-apatite (IOA) deposits in the Coastal Cordillera of northern Chile. The Cerro Principal magnetite ore body at El Romeral comprises massive magnetite intergrown with actinolite, with minor apatite, scapolite, and sulfides (pyrite ± chalcopyrite). Several generations of magnetite were identified by using a combination of optical and electron microscopy techniques. The main mineralization event is represented by zoned magnetite grains with inclusion-rich cores and inclusion-poor rims, which form the massive magnetite ore body. This main magnetite stage was followed by two late hydrothermal events that are represented by magnetite veinlets that crosscut the massive ore body and by disseminated magnetite in the andesite host rock and in the Romeral diorite. The sulfur stable isotope signature of the late hydrothermal sulfides indicates a magmatic origin for sulfur (δ34S between - 0.8 and 2.9‰), in agreement with previous δ34S data reported for other Chilean IOA and iron oxide-copper-gold deposits. New 40Ar/39Ar dating of actinolite associated with the main magnetite ore stage yielded ages of ca. 128 Ma, concordant within error with a U-Pb zircon age for the Romeral diorite (129.0 ± 0.9 Ma; mean square weighted deviation = 1.9, n = 28). The late hydrothermal magnetite-biotite mineralization is constrained at ca. 118 Ma by 40Ar/39Ar dating of secondary biotite. This potassic alteration is about 10 Ma younger than the main mineralization episode, and it may be related to post-mineralization dikes that crosscut and remobilize Fe from the main magnetite ore body. These data reveal a clear genetic association between magnetite ore formation, sulfide mineralization, and the diorite intrusion at El Romeral (at 129 Ma), followed by a late and more restricted stage of hydrothermal alteration associated with the emplacement of post-ore dikes at ca. 118 Ma. Therefore, this new evidence supports a magmatic-hydrothermal model for the

  10. A microbial-mineralization approach for syntheses of iron oxides with a high specific surface area.

    Science.gov (United States)

    Yagita, Naoki; Oaki, Yuya; Imai, Hiroaki

    2013-04-02

    Of minerals and microbes: A microbial-mineralization-inspired approach was used to facilitate the syntheses of iron oxides with a high specific surface area, such as 253 m(2)g(-1) for maghemite (γ-Fe(2)O(3)) and 148 m(2)g(-1) for hematite (α-Fe(2)O(3)). These iron oxides can be applied to electrode material of lithium-ion batteries, adsorbents, and catalysts. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Moessbauer and XRD Comparative Study of Host Rock and Iron Rich Mineral Samples from Paz del Rio Iron Ore Mineral Mine in Colombia

    International Nuclear Information System (INIS)

    Fajardo, M.; Perez Alcazar, G. A.; Moreira, A. M.; Speziali, N. L.

    2004-01-01

    A comparative study between the host rock and the iron rich mineral samples from the Paz del Rio iron ore mineral mine in Colombia was performed using X-ray diffraction and Moessbauer spectroscopy. Diffraction results of the iron rich mineral sample show that goethite, hematite, quartz, kaolinite and siderite are the main phases, and that a small amount of illite is also present. By Moessbauer spectroscopy at room temperature (RT) the presence of all the above mentioned phases was detected except quartz as well as an additional presence of small amount of biotite. The goethite, which appears as four sextets with hyperfine fields of 33.5, 30.5, 27.5 and 18.5 T, respectively, is the majority phase. This result shows the different grades of formation of this oxyhydroxide. The Moessbauer spectrum of this sample at 80 K presents the same phases obtained at RT without any superparamagnetic effect. In this case the goethite appears as two sextets. Diffraction results of the host rock sample show a large amount of quartz and kaolinite and small amounts of illite and biotite, whereas by Moessbauer spectroscopy illite, kaolinite and biotite were detected.

  12. Hcl extractable minerals (Iron ,Zinc ,Calcium, Lead,Aluminum and ...

    African Journals Online (AJOL)

    Georgette Koduah

    2012-05-07

    http://www.iom.edu/Activities/Nutrition/SummaryDRIs/DRI-Tables.aspx. National Research Council. National Academy of Sciences, 2011. Accessed. May 7, 2012. 29. Coltman CA Pagophagia and Iron lack. JAMA, 1969; 207: 513- 516. 30. Dreyer MJ, Chaushev PG and RF Gledhill Biochemical investigations in geophagia.

  13. Reconstruction of a digital core containing clay minerals based on a clustering algorithm

    Science.gov (United States)

    He, Yanlong; Pu, Chunsheng; Jing, Cheng; Gu, Xiaoyu; Chen, Qingdong; Liu, Hongzhi; Khan, Nasir; Dong, Qiaoling

    2017-10-01

    It is difficult to obtain a core sample and information for digital core reconstruction of mature sandstone reservoirs around the world, especially for an unconsolidated sandstone reservoir. Meanwhile, reconstruction and division of clay minerals play a vital role in the reconstruction of the digital cores, although the two-dimensional data-based reconstruction methods are specifically applicable as the microstructure reservoir simulation methods for the sandstone reservoir. However, reconstruction of clay minerals is still challenging from a research viewpoint for the better reconstruction of various clay minerals in the digital cores. In the present work, the content of clay minerals was considered on the basis of two-dimensional information about the reservoir. After application of the hybrid method, and compared with the model reconstructed by the process-based method, the digital core containing clay clusters without the labels of the clusters' number, size, and texture were the output. The statistics and geometry of the reconstruction model were similar to the reference model. In addition, the Hoshen-Kopelman algorithm was used to label various connected unclassified clay clusters in the initial model and then the number and size of clay clusters were recorded. At the same time, the K -means clustering algorithm was applied to divide the labeled, large connecting clusters into smaller clusters on the basis of difference in the clusters' characteristics. According to the clay minerals' characteristics, such as types, textures, and distributions, the digital core containing clay minerals was reconstructed by means of the clustering algorithm and the clay clusters' structure judgment. The distributions and textures of the clay minerals of the digital core were reasonable. The clustering algorithm improved the digital core reconstruction and provided an alternative method for the simulation of different clay minerals in the digital cores.

  14. Reconstruction of a digital core containing clay minerals based on a clustering algorithm.

    Science.gov (United States)

    He, Yanlong; Pu, Chunsheng; Jing, Cheng; Gu, Xiaoyu; Chen, Qingdong; Liu, Hongzhi; Khan, Nasir; Dong, Qiaoling

    2017-10-01

    It is difficult to obtain a core sample and information for digital core reconstruction of mature sandstone reservoirs around the world, especially for an unconsolidated sandstone reservoir. Meanwhile, reconstruction and division of clay minerals play a vital role in the reconstruction of the digital cores, although the two-dimensional data-based reconstruction methods are specifically applicable as the microstructure reservoir simulation methods for the sandstone reservoir. However, reconstruction of clay minerals is still challenging from a research viewpoint for the better reconstruction of various clay minerals in the digital cores. In the present work, the content of clay minerals was considered on the basis of two-dimensional information about the reservoir. After application of the hybrid method, and compared with the model reconstructed by the process-based method, the digital core containing clay clusters without the labels of the clusters' number, size, and texture were the output. The statistics and geometry of the reconstruction model were similar to the reference model. In addition, the Hoshen-Kopelman algorithm was used to label various connected unclassified clay clusters in the initial model and then the number and size of clay clusters were recorded. At the same time, the K-means clustering algorithm was applied to divide the labeled, large connecting clusters into smaller clusters on the basis of difference in the clusters' characteristics. According to the clay minerals' characteristics, such as types, textures, and distributions, the digital core containing clay minerals was reconstructed by means of the clustering algorithm and the clay clusters' structure judgment. The distributions and textures of the clay minerals of the digital core were reasonable. The clustering algorithm improved the digital core reconstruction and provided an alternative method for the simulation of different clay minerals in the digital cores.

  15. Fixation of Selenium by Clay Minerals and Iron Oxides

    DEFF Research Database (Denmark)

    Hamdy, A. A.; Nielsen, Gunnar Gissel

    1977-01-01

    In studying Se fixation, soil components capable of retaining Se were investigated. The importance of Fe hydrous oxides in the fixation of Se was established. The clay minerals common to soils, such as kaolinite, montmorillonite and vermiculite, all exhibited Se fixation, but greater fixation occ...

  16. Effects of iron-containing minerals on hydrothermal reactions of ketones

    Science.gov (United States)

    Yang, Ziming; Gould, Ian R.; Williams, Lynda B.; Hartnett, Hilairy E.; Shock, Everett L.

    2018-02-01

    Hydrothermal organic transformations occurring in geochemical processes are influenced by the surrounding environments including rocks and minerals. This work is focused on the effects of five common minerals on reactions of a model ketone substrate, dibenzylketone (DBK), in an experimental hydrothermal system. Ketones play a central role in many hydrothermal organic functional group transformations, such as those converting hydrocarbons to oxygenated compounds; however, how these minerals control the hydrothermal chemistry of ketones is poorly understood. Under the hydrothermal conditions of 300 °C and 70 MPa for up to 168 h, we observed that, while quartz (SiO2) and corundum (Al2O3) had no detectable effect on the hydrothermal reactions of DBK, iron-containing minerals, such as hematite (Fe2O3), magnetite (Fe3O4), and troilite (synthetic FeS), accelerated the reaction of DBK by up to an order of magnitude. We observed that fragmentation products, such as toluene and bibenzyl, dominated in the presence of hematite or magnetite, while use of troilite gave primarily the reduction products, e.g., 1, 3-diphenyl-propane and 1, 3-diphenyl-2-propanol. The roles of the three iron minerals in these transformations were further explored by (1) control experiments with various mineral surface areas, (2) measuring H2 in hydrothermal solutions, and (3) determining hydrogen balance among the organic products. These results suggest the reactions catalyzed by iron oxides (hematite and magnetite) are promoted mainly by the mineral surfaces, whereas the sulfide mineral (troilite) facilitated the reduction of ketone in the reaction solution. Therefore, this work not only provides a useful chemical approach to study and uncover complicated hydrothermal organic-mineral interactions, but also fosters a mechanistic understanding of ketone reactions in the deep carbon cycle.

  17. Iron utilization and liver mineral concentrations in rats fed safflower oil, flaxseed oil, olive oil, or beef tallow in combination with different concentrations of dietary iron.

    Science.gov (United States)

    Shotton, Andrea D; Droke, Elizabeth A

    2004-03-01

    Diets with a higher proportion of polyunsaturated fatty acids (i.e., linoleic acid) have decreased iron absorption and utilization compared with diets containing a higher proportion of the saturated fatty acid stearic acid (e.g., beef tallow). However, less is known regarding the influence of other polyunsaturated or monounsaturated fatty acids, along with higher dietary iron, on iron absorption and utilization. The present study was conducted to compare the effects of dietary fat sources known to vary in (n-3), (n-6), and (n-9) fatty acids on iron utilization and liver mineral concentrations. Male weanling rats were fed a diet containing 10, 35, or 100 microg/g iron in combination with safflower oil, flaxseed oil, olive oil, or beef tallow for 8 wk. Indicators of iron status, iron utilization, and liver iron concentrations were unaffected by an interaction between the fat source and iron concentration. Plasma copper was the only variable affected by an interaction between the fat source and dietary iron. Findings of this study demonstrate that flaxseed oil and olive oil may alter tissue minerals and affect iron utilization. Further studies should be conducted to establish the effect of varying (n-3), (n-6), and (n-9) fatty acids on trace mineral status and iron utilization.

  18. Getting rid of the unwanted: highlights of developments and challenges of biobeneficiation of iron ore minerals-a review.

    Science.gov (United States)

    Adeleke, Rasheed A

    2014-12-01

    The quest for quality mineral resources has led to the development of many technologies that can be used to refine minerals. Biohydrometallurgy is becoming an increasingly acceptable technology worldwide because it is cheap and environmentally friendly. This technology has been successfully developed for some sulphidic minerals such as gold and copper. In spite of wide acceptability of this technology, there are limitations to its applications especially in the treatment of non-sulphidic minerals such as iron ore minerals. High levels of elements such as potassium (K) and phosphorus (P) in iron ore minerals are known to reduce the quality and price of these minerals. Hydrometallurgical methods that are non-biological involving the use of chemicals are usually used to deal with this problem. However, recent advances in mining technologies favour green technologies, known as biohydrometallurgy, with minimal impact on the environment. This technology can be divided into two, namely bioleaching and biobeneficiation. This review focuses on Biobeneficiation of iron ore minerals. Biobeneficiation of iron ore is very challenging due to the low price and chemical constitution of the ore. There are substantial interests in the exploration of this technology for improving the quality of iron ore minerals. In this review, current developments in the biobeneficiation of iron ore minerals are considered, and potential solutions to challenges faced in the wider adoption of this technology are proposed.

  19. Conductive iron oxide minerals accelerate syntrophic cooperation in methanogenic benzoate degradation

    Energy Technology Data Exchange (ETDEWEB)

    Zhuang, Li; Tang, Jia; Wang, Yueqiang; Hu, Min; Zhou, Shungui, E-mail: sgzhou@soil.gd.cn

    2015-08-15

    Highlights: • Paddy soil contaminated with benzoate incubated with hematite and magnetite. • Iron oxides addition enhanced methanogenic benzoate degradation by 25–53%. • The facilitated syntrophy might involve direct interspecies electron transfer. • Bacillaceae, Peptococcaceae, and Methanobacterium are potentially involved. - Abstract: Recent studies have suggested that conductive iron oxide minerals can facilitate syntrophic metabolism of the methanogenic degradation of organic matter, such as ethanol, propionate and butyrate, in natural and engineered microbial ecosystems. This enhanced syntrophy involves direct interspecies electron transfer (DIET) powered by microorganisms exchanging metabolic electrons through electrically conductive minerals. Here, we evaluated the possibility that conductive iron oxides (hematite and magnetite) can stimulate the methanogenic degradation of benzoate, which is a common intermediate in the anaerobic metabolism of aromatic compounds. The results showed that 89–94% of the electrons released from benzoate oxidation were recovered in CH{sub 4} production, and acetate was identified as the only carbon-bearing intermediate during benzoate degradation. Compared with the iron-free controls, the rates of methanogenic benzoate degradation were enhanced by 25% and 53% in the presence of hematite and magnetite, respectively. This stimulatory effect probably resulted from DIET-mediated methanogenesis in which electrons transfer between syntrophic partners via conductive iron minerals. Phylogenetic analyses revealed that Bacillaceae, Peptococcaceae, and Methanobacterium are potentially involved in the functioning of syntrophic DIET. Considering the ubiquitous presence of iron minerals within soils and sediments, the findings of this study will increase the current understanding of the natural biological attenuation of aromatic hydrocarbons in anaerobic environments.

  20. Determination of iron in natural and mineral waters by flame atomic absorption spectrometry

    Directory of Open Access Journals (Sweden)

    ROLANDAS KAZLAUSKAS

    2004-05-01

    Full Text Available Simple methods for the determination of Fe in natural and mineral waters by flame atomic absorption spectrometry (AAS are suggested. The results of the investigation of selectivity of the proposed AAS method proved that this procedure is not affected by high concentrations of other metals. The calibration graph for iron was linear at levels near the detection limit up to at least 0.10 mg ml-1. For the determination of microamounts of iron in mineral waters, an extraction AAS technique was developed. Iron was retained as Fe-8-oxyquinoline complex and extracted into chloroform. The optimal conditions for the extraction of the iron complex were determined. The AAS method was applied to the determination of Fe in mineral waters and natural waters from different areas of Lithuania. The accuracy of the developed method was sufficient and evaluated in comparison with a photometric method. The obtained results demonstrated that the procedure could be successfully applied for the analysis of water samples with satisfactory accuracy.

  1. Atmospheric processing outside clouds increases soluble iron in mineral dust.

    Science.gov (United States)

    Shi, Zongbo; Krom, Michael D; Bonneville, Steeve; Benning, Liane G

    2015-02-03

    Iron (Fe) is a key micronutrient regulating primary productivity in many parts of the global ocean. Dust deposition is an important source of Fe to the surface ocean, but most of this Fe is biologically unavailable. Atmospheric processing and reworking of Fe in dust aerosol can increase the bioavailable Fe inputs to the ocean, yet the processes are not well understood. Here, we experimentally simulate and model the cycling of Fe-bearing dust between wet aerosol and cloud droplets. Our results show that insoluble Fe in dust particles readily dissolves under acidic conditions relevant to wet aerosols. By contrast, under the higher pH conditions generally relevant to clouds, Fe dissolution tends to stop, and dissolved Fe precipitates as poorly crystalline nanoparticles. If the dust-bearing cloud droplets evaporated again (returning to the wet aerosol stage with low pH), those neo-formed Fe nanoparticles quickly redissolve, while the refractory Fe-bearing phases continue to dissolve gradually. Overall, the duration of the acidic, wet aerosol stage ultimately increases the amount of potentially bioavailable Fe delivered to oceans, while conditions in clouds favor the formation of Fe-rich nanoparticles in the atmosphere.

  2. Use of a portable X-ray analyser for manganese and iron assay in minerals

    International Nuclear Information System (INIS)

    Taqueda, M.H.S.; Agudo, E.G.

    1975-01-01

    The use of a protable X-ray fluorescence analyser for manganese and iron assay in minerals is described. The concentration range in the measured samples was 30% to 60% for Mn and 2% to 20% for Fe. The excitation source used was a 3 mCi 109 Cd sealed source. Balanced filters were used for the X-ray analysis. The statistical study of results showed a precision better than 0,5 for Mn, but only 4% for iron. They can be improved either increasing the counting time or using a 238 Pu source

  3. Minerals

    Directory of Open Access Journals (Sweden)

    Vaquero, M. P.

    1998-08-01

    Full Text Available The possible changes in the mineral composition of food during frying could be the consequence of losses by leaching, or changes in concentrations caused by exchanges between the food and culinary fat of other compounds. The net result depends on the type of food, the frying fat used and the frying process. Moreover, the modifications that frying produces in other nutrients could indirectly affect the availability of dietary minerals. The most outstanding ones are those that can take place in the fat or in the protein. With respect to the interactions between frying oils and minerals, we have recent knowledge concerning the effects of consuming vegetable oils used in repeated fryings of potatoes without turnover, on the nutritive utilization of dietary minerals. The experiments have been carried out in pregnant and growing rats, which consumed diets containing, as a sole source of fat, the testing frying oils or unused oils. It seems that the consumption of various frying oils, with a polar compound content lower or close to the maximum limit of 25% accepted for human consumption, does not alter the absorption and metabolism of calcium, phosphorous, iron or copper. Magnesium absorption from diets containing frying oils tends to increase but the urinary excretion of this element increases, resulting imperceptible the variations in the magnesium balance. The urinary excretion of Zn also increased although its balance remained unchanged. Different studies referring to the effects of consuming fried fatty fish on mineral bioavailability will also be presented. On one hand, frying can cause structural changes in fish protein, which are associated with an increase in iron absorption and a decrease in body zinc retention. The nutritive utilization of other elements such as magnesium, calcium and copper seems to be unaffected. On the other hand; it has been described that an excess of fish fatty acids in the diet produces iron depletion, but when fatty

  4. Pure-iron/iron-based-alloy hybrid soft magnetic powder cores compacted at ultra-high pressure

    Science.gov (United States)

    Saito, Tatsuya; Tsuruta, Hijiri; Watanabe, Asako; Ishimine, Tomoyuki; Ueno, Tomoyuki

    2018-04-01

    We developed Fe/FeSiAl soft magnetic powder cores (SMCs) for realizing the miniaturization and high efficiency of an electromagnetic conversion coil in the high-frequency range (˜20 kHz). We found that Fe/FeSiAl SMCs can be formed with a higher density under higher compaction pressure than pure-iron SMCs. These SMCs delivered a saturation magnetic flux density of 1.7 T and iron loss (W1/20k) of 158 kW/m3. The proposed SMCs exhibited similar excellent characteristics even in block shapes, which are closer to the product shapes.

  5. Pure-iron/iron-based-alloy hybrid soft magnetic powder cores compacted at ultra-high pressure

    Directory of Open Access Journals (Sweden)

    Tatsuya Saito

    2018-04-01

    Full Text Available We developed Fe/FeSiAl soft magnetic powder cores (SMCs for realizing the miniaturization and high efficiency of an electromagnetic conversion coil in the high-frequency range (∼20 kHz. We found that Fe/FeSiAl SMCs can be formed with a higher density under higher compaction pressure than pure-iron SMCs. These SMCs delivered a saturation magnetic flux density of 1.7 T and iron loss (W1/20k of 158 kW/m3. The proposed SMCs exhibited similar excellent characteristics even in block shapes, which are closer to the product shapes.

  6. Evaluation of constitutive iron reductase (AtFRO2 expression on mineral accumulation and distribution in soybean (Glycine max. L

    Directory of Open Access Journals (Sweden)

    Marta Wilton Vasconcelos

    2014-04-01

    Full Text Available Iron is an important micronutrient in human and plant nutrition. Adequate iron nutrition during crop production is central for assuring appropriate iron concentrations in the harvestable organs, for human food or animal feed. The whole-plant movement of iron involves several processes, including the reduction of ferric to ferrous iron at several locations throughout the plant, prior to transmembrane trafficking of ferrous iron. In this study, soybean plants that constitutively expressed the AtFRO2 iron reductase gene were analyzed for leaf iron reductase activity, as well as the effect of this transgene's expression on root, leaf, pod wall, and seed mineral concentrations. High Fe supply, in combination with the constitutive expression of AtFRO2, resulted in significantly higher concentrations of different minerals in roots (K, P, Zn, Ca, Ni, Mg and Mo, pod walls (Fe, K, P, Cu and Ni, leaves (Fe, P, Cu, Ca, Ni and Mg and seeds (Fe, Zn, Cu and Ni. Leaf and pod wall iron concentrations increased as much as 500% in transgenic plants, while seed iron concentrations only increased by 10%, suggesting that factors other than leaf and pod wall reductase activity were limiting the translocation of iron to seeds. Protoplasts isolated from transgenic leaves had three-fold higher reductase activity than controls. Expression levels of the iron storage protein, ferritin, were higher in the transgenic leaves than in wild-type, suggesting that the excess iron may be stored as ferritin in the leaves and therefore unavailable for phloem loading and delivery to the seeds. Also, citrate and malate levels in the roots and leaves of transgenic plants were significantly higher than in wild-type, suggesting that organic acid production could be related to the increased accumulation of minerals in roots, leaves and pod walls, but not in the seeds. All together, these results suggest a more ubiquitous role for the iron reductase in whole-plant mineral accumulation and

  7. Non-chondritic iron isotope ratios in planetary mantles as a result of core formation

    Science.gov (United States)

    Elardo, Stephen M.; Shahar, Anat

    2017-02-01

    Information about the materials and conditions involved in planetary formation and differentiation in the early Solar System is recorded in iron isotope ratios. Samples from Earth, the Moon, Mars and the asteroid Vesta reveal significant variations in iron isotope ratios, but the sources of these variations remain uncertain. Here we present experiments that demonstrate that under the conditions of planetary core formation expected for the Moon, Mars and Vesta, iron isotopes fractionate between metal and silicate due to the presence of nickel, and enrich the bodies' mantles in isotopically light iron. However, the effect of nickel diminishes at higher temperatures: under conditions expected for Earth's core formation, we infer little fractionation of iron isotopes. From our experimental results and existing conceptual models of magma ocean crystallization and mantle partial melting, we find that nickel-induced fractionation can explain iron isotope variability found in planetary samples without invoking nebular or accretionary processes. We suggest that near-chondritic iron isotope ratios of basalts from Mars and Vesta, as well as the most primitive lunar basalts, were achieved by melting of isotopically light mantles, whereas the heavy iron isotope ratios of terrestrial ocean floor basalts are the result of melting of near-chondritic Earth mantle.

  8. Atmospheric delivery of anthropogenic bioavailable iron from mineral dust to the ocean

    OpenAIRE

    伊藤, 彰記; 時, 宗波; ITO, Akinori; SHI, Zongbo

    2015-01-01

    Atmospheric deposition of anthropogenic soluble iron (Fe) to the ocean has been suggested to modulate primary ocean productivity and thus indirectly affect the climate. A key process contributing to anthropogenic sources of soluble Fe is associated with air pollution, which acidifies Fe-containing mineral aerosols during their transport and leads to Fe transformation from insoluble to soluble forms. However, there is large uncertainty in our estimate of this anthropogenic soluble Fe. Here, we...

  9. Delivery of anthropogenic bioavailable iron from mineral dust and combustion aerosols to the ocean

    OpenAIRE

    伊藤, 彰記; 時, 宗波; ITO, Akinori; SHI, Zongbo

    2016-01-01

    Atmospheric deposition of anthropogenic soluble iron (Fe) to the ocean has been suggested to modulate primary ocean productivity and thus indirectly affect the climate. A key process contributing to anthropogenic sources of soluble Fe is associated with air pollution, which acidifies Fe-containing mineral aerosols during their transport and leads to Fe transformation from insoluble to soluble forms. However, there is large uncertainty in our estimate of this anthropogenic soluble Fe. In this ...

  10. Siderophore-mediated iron dissolution from nontronites is controlled by mineral cristallochemistry

    Directory of Open Access Journals (Sweden)

    Damien eParrello

    2016-03-01

    Full Text Available Bacteria living in oxic environments experience iron deficiency due to limited solubility and slow dissolution kinetics of iron-bearing minerals. To cope with iron deprivation, aerobic bacteria have evolved various strategies, including release of siderophores or other organic acids that scavenge external Fe(III and deliver it to the cells. This research investigated the role of siderophores produced by Pseudomonas aeruginosa in the acquisition of Fe(III from two iron-bearing colloidal nontronites (NAu-1 and NAu-2, comparing differences in bioavailability related with site occupancy and distribution of Fe(III in the two lattices. To avoid both the direct contact of the mineral colloids with the bacterial cells and the uncontrolled particle aggregation, nontronite suspensions were homogenously dispersed in a porous silica gel before the dissolution experiments. A multiparametric approach coupling UV-vis spectroscopy and spectral decomposition algorithm was implemented to monitor simultaneously the solubilisation of Fe and the production of pyoverdine in microplate-based batch experiments. Both nontronites released Fe in a particle concentration-dependent manner when incubated with the wild-type P. aeruginosa strain, however iron released from NAu-2 was substantially greater than from NAu-1. The profile of organic acids produced in both cases was similar and may not account for the difference in the iron dissolution efficiency. In contrast, a pyoverdine-deficient mutant was unable to mobilise Fe(III from either nontronite, whereas iron dissolution occurred in abiotic experiments conducted with purified pyoverdine. Overall, our data provide evidence that P. aeruginosa indirectly mobilise Fe from nontronites primarily through the production of pyoverdine. The structural Fe present on the edges of Nau-2 rather than Nau-1 particles appears to be more bio-accessible, indicating that the distribution of Fe, in the tetrahedron and/or in the octahedron

  11. Mitochondrial iron accumulation exacerbates hepatic toxicity caused by hepatitis C virus core protein

    Energy Technology Data Exchange (ETDEWEB)

    Sekine, Shuichi; Ito, Konomi; Watanabe, Haruna; Nakano, Takafumi [Laboratory of Biopharmaceutics, Graduate School of Pharmaceutical Sciences, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba 260-8675 (Japan); Moriya, Kyoji; Shintani, Yoshizumi; Fujie, Hajime; Tsutsumi, Takeya; Miyoshi, Hideyuki; Fujinaga, Hidetake; Shinzawa, Seiko; Koike, Kazuhiko [Department of Internal Medicine, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655 (Japan); Horie, Toshiharu, E-mail: t.horie@thu.ac.jp [Laboratory of Biopharmaceutics, Graduate School of Pharmaceutical Sciences, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba 260-8675 (Japan)

    2015-02-01

    Patients with long-lasting hepatitis C virus (HCV) infection are at major risk of hepatocellular carcinoma (HCC). Iron accumulation in the livers of these patients is thought to exacerbate conditions of oxidative stress. Transgenic mice that express the HCV core protein develop HCC after the steatosis stage and produce an excess of hepatic reactive oxygen species (ROS). The overproduction of ROS in the liver is the net result of HCV core protein-induced dysfunction of the mitochondrial respiratory chain. This study examined the impact of ferric nitrilacetic acid (Fe-NTA)-mediated iron overload on mitochondrial damage and ROS production in HCV core protein-expressing HepG2 (human HCC) cells (Hep39b cells). A decrease in mitochondrial membrane potential and ROS production were observed following Fe-NTA treatment. After continuous exposure to Fe-NTA for six days, cell toxicity was observed in Hep39b cells, but not in mock (vector-transfected) HepG2 cells. Moreover, mitochondrial iron ({sup 59}Fe) uptake was increased in the livers of HCV core protein-expressing transgenic mice. This increase in mitochondrial iron uptake was inhibited by Ru360, a mitochondrial Ca{sup 2+} uniporter inhibitor. Furthermore, the Fe-NTA-induced augmentation of mitochondrial dysfunction, ROS production, and cell toxicity were also inhibited by Ru360 in Hep39b cells. Taken together, these results indicate that Ca{sup 2+} uniporter-mediated mitochondrial accumulation of iron exacerbates hepatocyte toxicity caused by the HCV core protein. - Highlights: • Iron accumulation in the livers of patients with hepatitis C virus (HCV) infection is thought to exacerbate oxidative stress. • The impact of iron overload on mitochondrial damage and ROS production in HCV core protein-expressing cells were examined. • Mitochondrial iron uptake was increased in the livers of HCV core protein-expressing transgenic mice. • Ca{sup 2+} uniporter-mediated mitochondrial accumulation of iron exacerbates

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

    Science.gov (United States)

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

    1994-01-01

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

  13. Iron Mineral Catalyzed C-H Activation As a Potential Pathway for Halogenation Processes

    Science.gov (United States)

    Tubbesing, C.; Schoeler, H. F.; Benzing, K.; Krause, T.; Lippe, S.; Rudloff, M.

    2014-12-01

    Due to increasing drinking water demand of mankind and an expected climate change the impact of salt lakes and salt deserts will increase within the next decades. Furthermore, a rising sea level influences coastal areas like salt marshes and abets processes which will lead to elevated organohalogen formation. An additional increase of the global warming potential, of particle formation and stratospheric ozone depletion is expected. Understanding these multifaceted processes is essential for mankind to be prepared for these alterations of the atmosphere. For example, Keppler et al. (2000) described the production of volatile halogenated organic compounds via oxidation of organic matter driven by ferric iron. However, the formation of long-chained alkyl halides in salt lakes is yet undisclosed. Despite the relative "inertness" of alkanes a direct halogenation of these compounds might be envisaged. In 2005 Vaillancourt et al. discovered a nonheme iron enzyme which is able to halogenate organic compounds via generating the high valent ferryl cation as reaction center. Based on various publications about C-H activation (Bergman, 2007) we postulate a halogenation process in which an iron containing minerals catalyse the C-H bond cleavage of organic compounds in soils. The generated organic radicals are highly reactive towards halides connected to the iron complex. We suggest that next to diagenetically altered iron containing enzymes, minerals such as oxides, hydroxides and sulfides are involved in abiotic halogenation processes. We applied the amino acid methionine as organic model compound and soluble iron species as reactants. All samples were incubated in aqueous phases containing various NaCl concentrations. As a result various halogenated ethanes and ethenes were identified as reaction products. References Bergman, R. G. (2007) Nature, 446(7134) 391-393 Keppler, F., et al. (2000) Nature, 403(6767) 298-301 Vaillancourt, F. H., et al. (2005) Nature, 436(7054) 1191-1194

  14. Melting of iron at the Earth's core conditions by molecular dynamics simulation

    Directory of Open Access Journals (Sweden)

    Y. N. Wu

    2011-09-01

    Full Text Available By large scale molecular dynamics simulations of solid-liquid coexistence, we have investigated the melting of iron under pressures from 0 to 364 GPa. The temperatures of liquid and solid regions, and the pressure of the system are calculated to estimate the melting point of iron. We obtain the melting temperature of iron is about 6700±200K under the inner-outer core boundary, which is in good agreement with the result of Alfè et al. By the pair analysis technique, the microstructure of liquid iron under higher pressures is obviously different from that of lower pressures and ambient condition, indicating that the pressure-induced liquid-liquid phase transition may take place in iron melts.

  15. Impact of Bioreduction on Remobilization of Adsorbed Cadmium on Iron Minerals in Anoxic Condition.

    Science.gov (United States)

    Ghorbanzadeh, Nasrin; Lakzian, Amir; Halajnia, Akram; Choi, Ui-Kyu; Kim, Ki-Hyun; Kim, Jong-Oh; Kurade, Mayur; Jeon, Byong-Hun

    2017-06-01

      The impact of bioreduction on the remobilization of adsorbed cadmium Cd(II) on minerals, including hematite, goethite, and two iron(III)-rich clay minerals nontronites (NAU-1 and NAU-2) under anoxic conditions was investigated. Langmuir isotherm equation better described the sorption of Cd(II) onto the all minerals. The maximum adsorption capacity was 6.2, 18.1, 3.6, and 4 mg g-1 for hematite, goethite, NAU-1 and NAU-2, respectively. The desorption of Cd(II) was due to the production of Fe(II) as a result of bioreduction of structural Fe(III) in the minerals by Shewanella putrefaciens. The bioreduction of Cd(II)-loaded Fe(III) minerals was negligible during the initial 5 days followed by a rapid increase up to 20 days. The amount of Cd(II) in solution phase at the end of 30 days increased up to 0.07 mmol L-1 for hematite, NAU-1, and NAU-2 and 0.02 mmol L-1 for goethite. The X-ray diffraction study showed negligible changes in bioreduced minerals phases.

  16. Thermomagnetic identification of manganese and iron minerals present in soils and industrial dusts

    Science.gov (United States)

    Wawer, Małgorzata; Rachwał, Marzena; Jabłońska, Mariola; Krzykawski, Tomasz; Magiera, Tadeusz

    2017-04-01

    Many industries (e.g. metallurgy, power, cement, and coking plants) constitute a sources of industrial dusts containing technogenic magnetic particles (TMP). TMP are mostly iron oxides with ferrimagnetic or antiferromagnetic properties, therefore their presence in dusts, soils and sediments can be easily detected by magnetic susceptibility measurements. TMP, thanks their specific mineral and magnetic properties, and well developed specific surface area, are characterized by a chemical affinity for some elements like heavy metals. The main objective of this study was identification of manganese and iron (hydro)oxides occurring in industrial dusts and soils being under their deposition for long time period. In principle, Mn and Fe (hydro)oxides present in these samples originate from high-temperature technological processes. Soils samples (collected from different soil horizons) taken from surroundings of power station, iron/steel and non-ferrous plants as well as metallurgical dusts and fly ashes from power stations were subjected to investigation. During the studies temperature dependent magnetic susceptibility measurements and X-ray powder diffraction analyses were applied. Thermomagnetic analyses (K-T) revealed differences between samples from particular industries, however an inflexion at 450-500°C of all curves was observed indicating a probable occurrence of maghemite- or titanomagnetite-like phases. The curves of TMP emitted by power plants have inflection at 580 °C indicating that magnetite was the main magnetic phase. In case of TMP originated from non-ferrous metal smelting additional curve deflection at 130 and 210 °C occurred relating to intermediate titanomagnetite or iron sulfides. X-ray diffraction proved the occurrence of magnetite and maghemite in almost all samples, especially connected with power industry and iron/steel metallurgy. Mineral analysis revealed that kind of industrial process influenced on the dominating mineral forms found in

  17. Adsorption of Trametes versicolor laccase to soil iron and aluminum minerals: enzyme activity, kinetics and stability studies.

    Science.gov (United States)

    Wu, Yue; Jiang, Ying; Jiao, Jiaguo; Liu, Manqiang; Hu, Feng; Griffiths, Bryan S; Li, Huixin

    2014-02-01

    Laccases play an important role in the degradation of soil phenol or phenol-like substance and can be potentially used in soil remediation through immobilization. Iron and aluminum minerals can adsorb extracellular enzymes in soil environment. In the present study, we investigated the adsorptive interaction of laccase, from the white-rot fungus Trametes versicolor, with soil iron and aluminum minerals and characterized the properties of the enzyme after adsorption to minerals. Results showed that both soil iron and aluminum minerals adsorbed great amount of laccase, independent of the mineral specific surface areas. Adsorbed laccases retained 26-64% of the activity of the free enzyme. Compared to the free laccase, all adsorbed laccases showed higher Km values and lower Vmax values, indicating a reduced enzyme-substrate affinity and a lower rate of substrate conversion in reactions catalyzed by the adsorbed laccase. Adsorbed laccases exhibited increased catalytic activities compared to the free laccase at low pH, implying the suitable application of iron and aluminum mineral-adsorbed T. versicolor laccase in soil bioremediation, especially in acid soils. In terms of the thermal profiles, adsorbed laccases showed decreased thermal stability and higher temperature sensitivity relative to the free laccase. Moreover, adsorption improved the resistance of laccase to proteolysis and extended the lifespan of laccase. Our results implied that adsorbed T. versicolor laccase on soil iron and aluminum minerals had promising potential in soil remediation. Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.

  18. Marine sulfate-reducing bacteria cause serious corrosion of iron under electroconductive biogenic mineral crust

    Science.gov (United States)

    Enning, Dennis; Venzlaff, Hendrik; Garrelfs, Julia; Dinh, Hang T; Meyer, Volker; Mayrhofer, Karl; Hassel, Achim W; Stratmann, Martin; Widdel, Friedrich

    2012-01-01

    Iron (Fe0) corrosion in anoxic environments (e.g. inside pipelines), a process entailing considerable economic costs, is largely influenced by microorganisms, in particular sulfate-reducing bacteria (SRB). The process is characterized by formation of black crusts and metal pitting. The mechanism is usually explained by the corrosiveness of formed H2S, and scavenge of ‘cathodic’ H2 from chemical reaction of Fe0 with H2O. Here we studied peculiar marine SRB that grew lithotrophically with metallic iron as the only electron donor. They degraded up to 72% of iron coupons (10 mm × 10 mm × 1 mm) within five months, which is a technologically highly relevant corrosion rate (0.7 mm Fe0 year−1), while conventional H2-scavenging control strains were not corrosive. The black, hard mineral crust (FeS, FeCO3, Mg/CaCO3) deposited on the corroding metal exhibited electrical conductivity (50 S m−1). This was sufficient to explain the corrosion rate by electron flow from the metal (4Fe0 → 4Fe2+ + 8e−) through semiconductive sulfides to the crust-colonizing cells reducing sulfate (8e− + SO42− + 9H+ → HS− + 4H2O). Hence, anaerobic microbial iron corrosion obviously bypasses H2 rather than depends on it. SRB with such corrosive potential were revealed at naturally high numbers at a coastal marine sediment site. Iron coupons buried there were corroded and covered by the characteristic mineral crust. It is speculated that anaerobic biocorrosion is due to the promiscuous use of an ecophysiologically relevant catabolic trait for uptake of external electrons from abiotic or biotic sources in sediments. PMID:22616633

  19. Iron(III) species formed during iron(II) oxidation and iron-core formation in bacterioferritin of Escherichia coli

    International Nuclear Information System (INIS)

    Hawkins, C.; Treffry, A.; Mackey, J.; Williams, J.M.; Andrews, S.C.; Guest, J.R.; Harrison, P.M.

    1996-01-01

    This paper describes a preliminary investigation of the mechanisms of Fe(II) oxidation and storage of Fe(III) in the bacterioferritin of Escherichia coli (EcBFR). Using Moessbauer spectroscopy to examine the initial oxidation of iron by EcBFR it is confirmed that this ferritin exhibits 'ferroxidase' activity and is shown that dimeric and monomeric iron species are produced as intermediates. The characteristics of ferroxidase activity in EcBFR is compare d with those of human H-chain ferritin (HuHF) and discuss the different Moessbauer parameters of their dimeric iron with reference to the structures of their di-metal sites. In addition, it is presented preliminary findings suggesting that after an initial 'burst', the rate of oxidation is greatly reduced, possibly due to blockage of the ferroxidase centre by bound iron. A new component, not found in HuHF and probably representing a small cluster of Fe(III) atoms, is reported

  20. Complex electrical monitoring of biopolymer and iron mineral precipitation for microbial enhanced hydrocarbon recovery

    Science.gov (United States)

    Wu, Y.; Hubbard, C. G.; Dong, W.; Hubbard, S. S.

    2011-12-01

    Microbially enhanced hydrocarbon recovery (MEHR) mechanisms are expected to be impacted by processes and properties that occur over a wide range of scales, ranging from surface interactions and microbial metabolism at the submicron scale to changes in wettability and pore geometry at the pore scale to geological heterogeneities at the petroleum reservoir scale. To eventually ensure successful, production-scale implementation of laboratory-developed MEHR procedures under field conditions, it is necessary to develop approaches that can remotely monitor and accurately predict the complex microbially-facilitated transformations that are expected to occur during MEHR treatments in reservoirs (such as the evolution of redox profiles, oil viscosity or matrix porosity/permeability modifications). Our initial studies are focused on laboratory experiments to assess the geophysical signatures of MEHR-induced biogeochemical transformations, with an ultimate goal of using these approaches to monitor field treatments. Here, we explore the electrical signatures of two MEHR processes that are designed to produce end-products that will plug high permeability zones in reservoirs and thus enhance sweep efficiency. The MEHR experiments to induce biopolymers (in this case dextran) and iron mineral precipitates were conducted using flow-through columns. Leuconostoc mesenteroides, a facultative anaerobe, known to produce dextran from sucrose was used in the biopolymer experiments. Paused injection of sucrose, following inoculation and initial microbial attachment, was carried out on daily basis, allowing enough time for dextran production to occur based on batch experiment observations. Electrical data were collected on daily basis and fluid samples were extracted from the column for characterization. Changes in electrical signal were not observed during initial microbial inoculation. Increase of electrical resistivity and decrease of electrical phase response were observed during the

  1. Kinetics and Products of Chromium(VI) Reduction by Iron(II/III)-Bearing Clay Minerals.

    Science.gov (United States)

    Joe-Wong, Claresta; Brown, Gordon E; Maher, Kate

    2017-09-05

    Hexavalent chromium is a water-soluble pollutant, the mobility of which can be controlled by reduction of Cr(VI) to less soluble, environmentally benign Cr(III). Iron(II/III)-bearing clay minerals are widespread potential reductants of Cr(VI), but the kinetics and pathways of Cr(VI) reduction by such clay minerals are poorly understood. We reacted aqueous Cr(VI) with two abiotically reduced clay minerals: an Fe-poor montmorillonite and an Fe-rich nontronite. The effects of ionic strength, pH, total Fe content, and the fraction of reduced structural Fe(II) [Fe(II)/Fe(total)] were examined. The last variable had the largest effect on Cr(VI) reduction kinetics: for both clay minerals, the rate constant of Cr(VI) reduction varies by more than 3 orders of magnitude with Fe(II)/Fe(total) and is described by a linear free energy relationship. Under all conditions examined, Cr and Fe K-edge X-ray absorption near-edge structure spectra show that the main Cr-bearing product is a Cr(III)-hydroxide and that Fe remains in the clay structure after reacting with Cr(VI). This study helps to quantify our understanding of the kinetics of Cr(VI) reduction by Fe(II/III)-bearing clay minerals and may improve predictions of Cr(VI) behavior in subsurface environments.

  2. Analysis of the plasma magnetohydrodynamic equilibrium in iron core transformer Tokamak HL-1M

    International Nuclear Information System (INIS)

    Chen Xiaoguang; Yuan Baoshan

    1992-01-01

    The physical and mathematical model are presented on the problem of MHD equilibrium with the self consistent in iron core transformer HL-1M. Calculation and analysis for the plasma equilibrium of the stable boundary and free boundary are shown respectively, in an axisymmetric equilibrium model of two dimensions. First, a variation formulation of the problem is written and the equations of the poloided flux ψ are solved by a finite element method; the Picard and Newton algorithms are tested for the non-linearities. The plasma boundary and the magnetic surfaces are being simulated, with the currents in the coils, the total plasma current, its current density function and the magnetic permeability of the iron being the data for the problem; a certain number of the characteristic parameter of the equilibrium configuration is calculated. Secondly, a simple method of calculation is adopted in the determination of equilibrium fields and currents in iron core HL-1M tokamak device. In the plasma equilibrium, the magnetic effect of the air gaps in the iron core and the iron magnetic shielded plate are considered in HL-1M device. Reliable data are provided for designing and constructing the poloidal field system of HL-1M device. A good computer code is constructed, which may be useful in operating on analysis for the future device

  3. Torque decomposition and control in an iron core linear permanent magnet motor.

    NARCIS (Netherlands)

    Overboom, T.T.; Smeets, J.P.C.; Stassen, J.M.; Jansen, J.W.; Lomonova, E.

    2012-01-01

    Abstract—This paper concerns the decomposition and control of the torque produced by an iron core linear permanent magnet motor. The proposed method is based on the dq0-decomposition of the three-phase currents using Park’s transformation. The torque is decomposed into a reluctance component and two

  4. Carbon Solubility in Silicon-Iron-Bearing Metals during Core Formation on Mercury

    Science.gov (United States)

    Vander Kaaden, Kathleen E.; McCubbin, Francis M.; Ross, D. Kent; Rapp, Jennifer F.; Danielson, Lisa R.; Keller, Lindsay P.; Righter, Kevin

    2016-01-01

    Recent results obtained from the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft showed the surface of Mercury has high S abundances (approximately 4 wt%) and low Iron(II) Oxide abundances (less than 2 wt%). Based on these extreme values, the oxygen fugacity of Mercury's surface materials was estimated to be approximately 3 to 7 log(sub 10) units below the IW buffer (Delta IW-3 to Delta IW-7). This highly reducing nature of the planet has resulted in a large core and relatively thin mantle, extending to only approximately 420 km depth (corresponding to a core-mantle boundary pressure of approximately 4-7 GPa) within the planet. Furthermore, MESSENGER results have suggested the presence of carbon on the surface of the planet. Previous experimental results from have also suggested the possibility of a primary floatation crust on Mercury composed of graphite, produced after a global magma ocean event. With these exotic conditions of this compositional end-member planet, it begs the question, what is the core composition of Mercury? Although no definitive conclusion has been reached, previous studies have made advances towards answering this question. Riner et al. and Chen et al. looked at iron sulfide systems and implemented various crystallization and layered core scenarios to try and determine the composition and structure of Mercury's core. Malavergne et al. examined core crystallization scenarios in the presence of sulfur and silicon. Hauck et al. used the most recent geophysical constraints from the MESSENGER spacecraft to model the internal structure of Mercury, including the core, in a iron-sulfur-silicon system. More recently, Chabot et al. conducted a series of metal-silicate partitioning experiments in a iron-sulfur-silicon system. These results showed the core of Mercury has the potential to contain more than 15 wt% silicon. However, with the newest results from MESSENGER's low altitude campaign, carbon is another

  5. Effect of superconducting solenoid model cores on spanwise iron magnet roll control

    Science.gov (United States)

    Britcher, C. P.

    1985-01-01

    Compared with conventional ferromagnetic fuselage cores, superconducting solenoid cores appear to offer significant reductions in the projected cost of a large wind tunnel magnetic suspension and balance system. The provision of sufficient magnetic roll torque capability has been a long-standing problem with all magnetic suspension and balance systems; and the spanwise iron magnet scheme appears to be the most powerful system available. This scheme utilizes iron cores which are installed in the wings of the model. It was anticipated that the magnetization of these cores, and hence the roll torque generated, would be affected by the powerful external magnetic field of the superconducting solenoid. A preliminary study has been made of the effect of the superconducting solenoid fuselage model core concept on the spanwise iron magnet roll torque generation schemes. Computed data for one representative configuration indicate that reductions in available roll torque occur over a range of applied magnetic field levels. These results indicate that a 30-percent increase in roll electromagnet capacity over that previously determined will be required for a representative 8-foot wind tunnel magnetic suspension and balance system design.

  6. SOLUBILITY OF IRON IN METALLIC HYDROGEN AND STABILITY OF DENSE CORES IN GIANT PLANETS

    International Nuclear Information System (INIS)

    Wahl, Sean M.; Wilson, Hugh F.; Militzer, Burkhard

    2013-01-01

    The formation of the giant planets in our solar system, and likely a majority of giant exoplanets, is most commonly explained by the accretion of nebular hydrogen and helium onto a large core of terrestrial-like composition. The fate of this core has important consequences for the evolution of the interior structure of the planet. It has recently been shown that H 2 O, MgO, and SiO 2 dissolve in liquid metallic hydrogen at high temperature and pressure. In this study, we perform ab initio calculations to study the solubility of an innermost metallic core. We find dissolution of iron to be strongly favored above 2000 K over the entire pressure range (0.4-4 TPa) considered. We compare with and summarize the results for solubilities on other probable core constituents. The calculations imply that giant planet cores are in thermodynamic disequilibrium with surrounding layers, promoting erosion and redistribution of heavy elements. Differences in solubility behavior between iron and rock may influence evolution of interiors, particularly for Saturn-mass planets. Understanding the distribution of iron and other heavy elements in gas giants may be relevant in understanding mass-radius relationships, as well as deviations in transport properties from pure hydrogen-helium mixtures

  7. Neyshabour turquoise mine: the first Iron Oxide Cu-Au-U-LREE (IOCG mineralized system in Iran

    Directory of Open Access Journals (Sweden)

    Mohammad Hasan Karimpour

    2011-11-01

    Full Text Available Neyshabour turquoise mine is located in northwest of Neyshabour, southern Quchan volcanic belt. Eocene andesite and dacite forming as lava and pyroclastic rocks cover most of the area. Subvolcanic diorite to syenite porphyry (granitoids of magnetite series intruded the volcanic rocks. Both volcanic and subvolcanic rocks are highly altered. Four types of alteration are recognized including: silicification, argillic, calcification and propylitic. Silicification is dominant followed by argillic alteration. Mineralization is present as stockwork, disseminated and hydrothermal breccia. Hypogene minerals are pyrite, magnetite, specularite, chalcopyrite, and bornite. Secondary minerals are turquoise, chalcocite, covellite, and iron oxides. A broad zone of gossan has developed in the area. Oxidized zone has a thickness of about 80 m. Mineralized samples show high anomalies of Cu, Au, Zn, As, Mo, Co, U, LREE, Nb, and Th. Both aeromagnetic and radiometric (U and Th maps show very strong anomalies (10 × 5km within the mineralized area. Based on geology, alteration, mineralization, geochemistry, and geophysics, Neyshabour turquoise mine is a large Iron oxide Cu-Au-U-LREE (IOCG mineralized system. In comparison with other IOCG deposits, it has some similarities with Olympic Dam (Australia and Candelaria (Chile. In comparison with Qaleh Zari and Kuh Zar mines, Neyshabour turquoise mine is the first Iron oxide Cu-Au-U-LREE (IOCG mineralized system discovered in Iran.

  8. Kinetics and Efficiency of H2O2 Activation by Iron-Containing Minerals and Aquifer Materials

    Science.gov (United States)

    Pham, Anh Le-Tuan; Doyle, Fiona M.; Sedlak, David L.

    2014-01-01

    To gain insight into factors that control H2O2 persistence and ˙OH yield in H2O2-based in situ chemical oxidation systems, the decomposition of H2O2 and transformation of phenol were investigated in the presence of iron-containing minerals and aquifer materials. Under conditions expected during remediation of soil and groundwater, the stoichiometric efficiency, defined as the amount of phenol transformed per mole of H2O2 decomposed, varied from 0.005 to 0.28%. Among the iron-containing minerals, iron oxides were 2 to 10 times less efficient in transforming phenol than iron-containing clays and synthetic iron-containing catalysts. In both iron-containing mineral and aquifer materials systems, the stoichiometric efficiency was inversely correlated with the rate of H2O2 decomposition. In aquifer materials systems, the stoichiometric efficiency was also inversely correlated with the Mn content, consistent with the fact that the decomposition of H2O2 on manganese oxides does not produce ˙OH. Removal of iron and manganese oxide coatings from the surface of aquifer materials by extraction with citrate-bicarbonate-dithionite slowed the rate of H2O2 decomposition on aquifer materials and increased the stoichiometric efficiency. In addition, the presence of 2 mM of dissolved SiO2 slowed the rate of H2O2 decomposition on aquifer materials by over 80% without affecting the stoichiometric efficiency. PMID:23047055

  9. Experimental and theoretical investigation of the iron core transformer for the EXTRAP T1 device

    International Nuclear Information System (INIS)

    Bures, M.

    1983-11-01

    The possibility of driving the discharge current of the toroidal EXTRAP T1 device, using the iron core transformer, is investigated. It is shown that the breakdown voltage 20 kV can be supplied, along the zero line of the vacuum magnetic field, at a time shorter than 1 μs. this is made possible by the transient build-up of the magnetic field in the iron core laminations. The plasma current rise time is determined by the evolution of the inductance and resistance of the discharge. This enables the plasma current to be built up to an amplitude I(sub)p=50 kA within 10-15 μs and sustained at this value during a steady-state period of 100 μs. The premagnetized iron core of the cross-sectional area 0.16 m 2 is sufficient to provide the necessary flux swing, if the saturation induction is not lower than 1 T. It is further concluded that the SiFe lamination is adequate for the present application. However, to reduce the stray field interfering with the zero line of the octupole field, a lamination of thickness d < 0.1 mm with high resistivity should be employed. The interlamination voltage should be reduced by segmenting the core. The steady-state is supplied by an 0.4Ω, 20 kV artificial line consisting of 20 μF capacitive elements. (author)

  10. Magnetite-apatite mineralization in Khanlogh iron deposit, northwest of Neyshaboor, NE Iran

    Science.gov (United States)

    Najafzadeh Tehrani, Parvin; Asghar Calagari, Ali; Velasco Roldan, Francisco; Simmonds, Vartan; Siahcheshm, Kamal

    2016-04-01

    Khanlogh iron deposit lies on Sabzehvar-Ghoochan Cenozoic magmatic belt in northwest of Neyshaboor, NE Iran. The lithologic units in this area include a series of sub-volcanic intrusive rocks like diorite porphyry, quartz-diorite porphyry, and micro-granodiorite of Oligocene age. Mineralization in this area occurred as veins, dissemination, and open space filling in brecciated zones within the host sub-volcanic intrusive bodies. Three distinct types of mineral associations can be distinguished, (1) diopside-magnetite, (2) magnetite-apatite, and (3) apatite-calcite. Microscopic examinations along with SEM and EPMA studies demonstrated that magnetite is the most common ore mineral occurring as solitary crystals. The euhedral magnetite crystals are accompanied by lamellar destabilized ilmenite and granular fluorapatite in magnetite-apatite ores. The results of EPMA revealed that the lamellar ilmenite, relative to host magnetite crystal, is notably enriched in MgO and MnO (average of 3.3 and 2.6 wt%, respectively; n=5), whereas magnetite is slighter enriched in Ti (TiO2 around 1.8 wt%) being average of MgO, MnO and V2O3 of 0.6wt%, 0.2wt%, and 0.6 wt% (respectively; n=20). Minerals such as chlorapatite, calcite, and chalcedony are also present in the magnetite-apatite ores. The samples from apatite-calcite ores contain coarse crystals of apatite and rhomboedral calcite. The plot of the EPMA data of Khanlogh iron ore samples on diagram of TiO2-V2O5 (Hou et al, 2011) illustrated that the data points lies between the well-known Kiruna and El Laco (Chile) iron deposits. The magnetite crystals in the sub-volcanic host rocks were possibly formed by immiscible iron oxide fluids during magmatic stage. However, the magnetite and apatite existing in the veins and breccia zones may have developed by high temperature hydrothermal fluids. Studies done by Purtov and Kotelnikova (1993) proved that the proportion of Ti in magnetite is related to fluoride complex in the hydrothermal

  11. Dirt in the Wound: Evaluating the Role of Iron in Antibacterial Minerals

    Science.gov (United States)

    Morrison, K. D.; Williams, L. B.

    2013-12-01

    The recent discovery of antibacterial clay deposits which are effective in killing antibiotic resistant bacteria may lead to the discovery of mineral based antibacterial mechanisms. These antibacterial clays have been shown to prevent the growth of a broad spectrum of bacteria, including methicillin-resistant Staphylococcus aureus MRSA and extended-spectrum beta lactamase (ESBL) Escherichia coli (antibiotic resistant strains) when tested in vitro. This study investigates the first antibacterial mineral deposit identified in the United States, the Oregon Mineral Technologies (OMT) mine, which formed from the hydrothermal alteration of porphyry andesites. Our hypothesis is that mixed-layered clay minerals containing nano-iron sulfides can release soluble transition metals at low pH which are antibacterial due to the rapid influx and precipitation of intracellular metal-oxides while generating reactive oxygen species (ROS) and damaging bacterial membranes. To test this hypothesis, E. coli (ATCC 25922) was reacted with clay suspensions and clay leachates (solutions equilibrated with clays for 24 hrs). Inductively coupled plasma mass spectrometry (ICP-MS) was used to measure the soluble transition metals that are leaching from the clays. Bioimaging using scanning transmission electron microscopy-electron energy loss spectroscopy (STEM-EELS) and scanning transmission X-ray microscopy (STXM) were used to investigate the precipitation of intracellular mineral particles and redox state of the soluble metals reacting with the bacteria. Reactive oxygen species (ROS) were measured using a spectrophotometric hydrogen peroxide assay (H2O2) assay. Aldehydes were measured using HPLC-UV-Vis (high-performance liquid chromatography-ultraviolet-visible). Antibacterial susceptibility testing and ICP-MS elemental analysis of the leachates reveals that low pH (2.5-3.1) samples containing mM levels of soluble Fe, Al and Ca are antibacterial. All other potential toxins are below the

  12. Mineral Physics Research on Earth's Core and UTeach Outreach Activities at UT Austin

    Science.gov (United States)

    Lin, J.; Wheat, A. J.

    2011-12-01

    Comprehension of the alloying effects of major candidate light elements on the phase diagram and elasticity of iron addresses pressing issues on the composition, thermal structures, and seismic features of the Earth's core. Integrating this mineral physics research with the educational objectives of the CAREER award was facilitated by collaboration with the University of Texas at Austin's premier teaching program, UTeach. The UTeach summer outreach program hosts three one-week summer camps every year exposing K-12th graders to university level academia, emphasizing math and science initiatives and research. Each week of the camp either focuses on math, chemistry, or geology. Many of the students were underrepresented minorities and some required simultaneous translation; this is an effect of the demographics of the region, and caused some language barrier challenges. The students' opportunity to see first-hand what it is like to be on a university campus, as well as being in a research environment, such as the mineral physics lab, helps them to visualize themselves in academia in the future. A collection of displayable materials with information about deep-Earth research were made available to participating students and teachers to disseminate accurate scientific knowledge and enthusiasm. These items included a diamond anvil cell and diagrams of the diamond crystal structure, the layers of the Earth, and the phases of carbon to show that one element can have very different physical properties purely based on differences in structure. The students learned how advanced X-ray and optical laser spectroscopies are used to study properties of planetary materials in the diamond anvil cell. Stress was greatly placed on the basic mathematical relationship between force, area, and pressure, the fundamental principle involved with diamond anvil cell research. Undergraduate researchers from the lab participated in the presentations and hands-on experiments, and answered any

  13. Effects of iron type in Fenton reaction on mineralization and biodegradability enhancement of hazardous organic compounds.

    Science.gov (United States)

    Khan, Eakalak; Wirojanagud, Wanpen; Sermsai, Nawarat

    2009-01-30

    The mineralization and biodegradability increase and their combination of two traditional and two relatively new organic contaminants by Fenton reagents with three different types of iron, Fe(2+), Fe(3+), and Fe(0) were investigated. The traditional contaminants examined were trichloroethene (TCE) and 2,4-dichlorophenol (2,4-DCP) while 1,4-dioxane (1,4-D) and 1,2,3-trichloropropane (TCP) were studied for the relatively new contaminants. The mineralization and biodegradability were represented by dissolved organic carbon (DOC) reduction and the ratio of biodegradable dissolved organic carbon and DOC, respectively. For all four contaminants, Fenton reagent using Fe(2+) was more effective in the DOC reduction than Fenton reagents using Fe(3+) and Fe(0) in most cases. The types of Fe that provided maximum biodegradability increase were not the same for all four compounds, Fe(3+) for TCE, Fe(0) for 2,4-DCP, Fe(2+) for 1,4-D, and Fe(3+) for TCP. When the combination of DOC elimination and biodegradability increase (least refractory fraction) was considered, Fe(2+) was the best choice except for 2,4-DCP which was susceptible to Fe(0) catalyzed Fenton reagent the most. The least refractory fractions remaining after 120 min of reaction were 20-25% for TCE, 2,4-DCP, and TCP and 30-40% for 1,4-D. The iron type in Fenton reaction also affected the type of mineralization kinetics of TCE, 2,4-DCP, and TCP as well as the types of degradation by-products of these contaminants. Some of the by-products found, such as isopropanol and propionic aldehyde, which were produced from Fe(0) catalyzed Fenton degradation of TCP, have not been previously reported.

  14. Influence of a soil enzyme on iron-cyanide complex speciation and mineral adsorption.

    Science.gov (United States)

    Zimmerman, Andrew R; Kang, Dong-Hee; Ahn, Mi-Youn; Hyun, Seunghun; Banks, M Katherine

    2008-01-01

    Cyanide is commonly found as ferrocyanide [Fe(II)(CN)(6)](-4) and in the more mobile form, ferricyanide [Fe(III)(CN)(6)](-3) in contaminated soils and sediments. Although soil minerals may influence ferrocyanide speciation, and thus mobility, the possible influence of soil enzymes has not been examined. In a series of experiments conducted under a range of soil-like conditions, laccase, a phenoloxidase enzyme derived from the fungi Trametes versicolor, was found to exert a large influence on iron-cyanide speciation and mobility. In the presence of laccase, up to 93% of ferrocyanide (36-362ppm) was oxidized to ferricyanide within 4h. No significant effect of pH (3.6 and 6.2) or initial ferrocyanide concentration on the extent or rate of oxidation was found and ferrocyanide oxidation did not occur in the absence of laccase. Relative to iron-cyanide-mineral systems without laccase, ferrocyanide adsorption to aluminum hydroxide and montmorillonite decreased in the presence of laccase and was similar to or somewhat greater than that of ferricyanide without laccase. Laccase-catalyzed conversion of ferrocyanide to ferricyanide was extensive though up to 33% of the enzyme was mineral-bound. These results demonstrate that soil enzymes can play a major role in ferrocyanide speciation and mobility. Biotic soil components must be considered as highly effective oxidation catalysts that may alter the mobility of metals and metal complexes in soil. Immobilized enzymes should also be considered for use in soil metal remediation efforts.

  15. Enlightening mineral iron sensing in Pseudomonas fluorescens by surface active maghemite nanoparticles: Involvement of the OprF porin.

    Science.gov (United States)

    Magro, Massimiliano; Fasolato, Luca; Bonaiuto, Emanuela; Andreani, Nadia Andrea; Baratella, Davide; Corraducci, Vittorino; Miotto, Giovanni; Cardazzo, Barbara; Vianello, Fabio

    2016-10-01

    Mineral iron(III) recognition by bacteria is considered a matter of debate. The peculiar surface chemistry of novel naked magnetic nanoparticles, called SAMNs (surface active maghemite nanoparticles) characterized by solvent exposed Fe(3+) sites on their surface, was exploited for studying mineral iron sensing in Pseudomonas fluorescens. SAMNs were applied for mimicking Fe(3+) ions in solution, acting as magnetically drivable probes to evaluate putative Fe(3+) recognition sites on the microorganism surface. Culture broths and nano-bio-conjugates were characterized by UV-Vis spectroscopy and mass spectrometry. The whole heritage of a membrane porin (OprF) of P. fluorescens Ps_22 cells was recognized and firmly bound by SAMNs. The binding of nanoparticles to OprF porin was correlated to a drastic inhibition of a siderophore (pyoverdine) biosynthesis and to the stimulation of the production and rate of formation of a secondary siderophore. The analysis of metabolic pathways, based on P. fluorescens Ps_22 genomic information, evidenced that this putative secondary siderophore does not belong to a selection of the most common siderophores. In the scenario of an adhesion mechanism, it is plausible to consider OprF as the biological component deputed to the mineral iron sensing in P. fluorescens Ps_22, as well as one key of siderophore regulation. The present work sheds light on mineral iron sensing in microorganisms. Peculiar colloidal naked iron oxide nanoparticles offer a useful approach for probing the adhesion of bacterial surface on mineral iron for the identification of the specific recognition site for this iron uptake regulation in microorganisms. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Are iron-phosphate minerals a sink for phosphorus in anoxic Black Sea sediments?

    Directory of Open Access Journals (Sweden)

    Nikki Dijkstra

    Full Text Available Phosphorus (P is a key nutrient for marine organisms. The only long-term removal pathway for P in the marine realm is burial in sediments. Iron (Fe bound P accounts for a significant proportion of this burial at the global scale. In sediments underlying anoxic bottom waters, burial of Fe-bound P is generally assumed to be negligible because of reductive dissolution of Fe(III (oxyhydroxides and release of the associated P. However, recent work suggests that Fe-bound P is an important burial phase in euxinic (i.e. anoxic and sulfidic basin sediments in the Baltic Sea. In this study, we investigate the role of Fe-bound P as a potential sink for P in Black Sea sediments overlain by oxic and euxinic bottom waters. Sequential P extractions performed on sediments from six multicores along two shelf-to-basin transects provide evidence for the burial of Fe-bound P at all sites, including those in the euxinic deep basin. In the latter sediments, Fe-bound P accounts for more than 20% of the total sedimentary P pool. We suggest that this P is present in the form of reduced Fe-P minerals. We hypothesize that these minerals may be formed as inclusions in sulfur-disproportionating Deltaproteobacteria. Further research is required to elucidate the exact mineral form and formation mechanism of this P burial phase, as well as its role as a sink for P in sulfide-rich marine sediments.

  17. Are iron-phosphate minerals a sink for phosphorus in anoxic Black Sea sediments?

    Science.gov (United States)

    Dijkstra, Nikki; Kraal, Peter; Kuypers, Marcel M M; Schnetger, Bernhard; Slomp, Caroline P

    2014-01-01

    Phosphorus (P) is a key nutrient for marine organisms. The only long-term removal pathway for P in the marine realm is burial in sediments. Iron (Fe) bound P accounts for a significant proportion of this burial at the global scale. In sediments underlying anoxic bottom waters, burial of Fe-bound P is generally assumed to be negligible because of reductive dissolution of Fe(III) (oxyhydr)oxides and release of the associated P. However, recent work suggests that Fe-bound P is an important burial phase in euxinic (i.e. anoxic and sulfidic) basin sediments in the Baltic Sea. In this study, we investigate the role of Fe-bound P as a potential sink for P in Black Sea sediments overlain by oxic and euxinic bottom waters. Sequential P extractions performed on sediments from six multicores along two shelf-to-basin transects provide evidence for the burial of Fe-bound P at all sites, including those in the euxinic deep basin. In the latter sediments, Fe-bound P accounts for more than 20% of the total sedimentary P pool. We suggest that this P is present in the form of reduced Fe-P minerals. We hypothesize that these minerals may be formed as inclusions in sulfur-disproportionating Deltaproteobacteria. Further research is required to elucidate the exact mineral form and formation mechanism of this P burial phase, as well as its role as a sink for P in sulfide-rich marine sediments.

  18. Modern Cored Wire Injection 2PE-9 Method in the Production of Ductile Iron

    Directory of Open Access Journals (Sweden)

    E. Guzik

    2012-04-01

    Full Text Available The results of studies on the use of modern two cored wires injection method for production of nodular graphite cast iron with use of unique implementation of drum ladle as a treatment/ transport and casting ladle instead vertical treatment ladle was described. The injection of length of Ø 9mm wires, cored: in FeSi + Mg nodulariser mixture and inoculant master alloy is a treatment method which can be used to produce iron melted in coreless induction furnace. This paper describes the results of using this method for possibility production of ductile iron under specific industrial conditions. In this case was taken ductile iron with material designation: EN-GJS-450- 10 Grade according PN-EN 1563:2000. Microstructure of 28 trials was controlled on internally used sample which has been correlated with standard sample before. The paper presents typical metallic matrix and graphite characteristic. Additionally, mechanical properties were checked in one experiment. Because of further possibility treatment temperature reduction only the rough magnesium recovery and cost of this new method are given.

  19. Testing the Prediction of Iron Alteration Minerals on Low Albedo Asteroids

    Science.gov (United States)

    Jarvis, K. S.; Vilas, Faith; Howell, E.; Kelley, M.; Cochran, A.

    1999-01-01

    Absorption features centered near 0.60 - 0.65 and 0.80 - 0.90 micron were identified in the spectra of three low-albedo main-belt (165, 368, 877) and two low-albedo outer-belt (225, 334) asteroids (Vilas et al., Icarus, v. 109,274,1994). The absorption features were attributed to charge transfer transitions in iron alteration minerals such as goethite, hematite, and jarosite, all products of aqueous alteration. Concurrently, Jarvis et al. (LPSC XXIV, 715, 1993) presented additional spectra of low-albedo asteroids that had absorption features centered near 0.60 - 0.65 micron without the longer wavelength feature. Since these two features in iron oxides originate from the same ground state, and the longer wavelength feature requires less energy to exist, the single shorter wavelength feature cannot be caused by the iron alteration minerals. In addition, spectra of minerals such as hematite and goethite show a rapid increase in reflectance beginning near 0.5 micron absent in the low-albedo asteroid spectra. The absence of this rise has been attributed to its suppresion from opaques in the surface material. Spectra on more than one night were available for only one of these five asteroids, 225 Henrietta, and showed good repeatability of the 0.65-micron feature. We have acquired additional spectra of all five asteroids in order to test the repeatability of the 0.65-micron feature, and the presence and repeatability of the features centered near 0.8 - 0.9 micron. We specifically will test the possibility that longer wavelength features could be caused by incomplete removal of telluric water. Asteroid 877 Walkure is a member of the Nysa-Hertha family, and will be compared to spectra of other members of that family. Data were acquired in 1996 and 1999 on the 2.1-m telescope with a facility cassegrain spectrograph, McDonald Observatory, Univ. Of Texas, and the 1.5-m telescope with facility cassegrain spectrograph at CTIO. This research is supported by the NASA Planetary

  20. Lung cancer and bronchi-pulmonary diseases of iron uranium miners

    International Nuclear Information System (INIS)

    Gneusheva, G. I.; Uspenskaya, K. M.

    2004-01-01

    The lung cancer mortality has been analyzed for 2.582 miners employed from 1943 to 1961. All persons observed had three years occupation at least. Basing upon the lung cancer risk value per unit of the exposure, the assessment of the effective standard of pulmonary organ irradiation to radon progeny was elaborated and mortality excess was calcuated. Medical demography studies of morbidity and mortality were elaborated for silicosis, silicotuberculosis, lung cancer and occupational bronchitis versus the magnitude of dust and radiation exposure. Annual and cumulative exposures have been assessed for seven cohorts of miners employed and vast primary material has been accumulated for the period of 40 years (1943-1984). Intensive indice of mortality were determined for observation periods. The mortality excess was compared to cumulated radiation exposure. The lung cancer mortality excess in iron-uranium miners was 3.3 cases per 106 man-years per 1 WLM; 4.8 cases per 106 man-years per 1 WLM was assessed if first years of occupation are negected. The latent period from radiation exposure to death from lung cancer is generally ten year or more. Changes of miners labor conditions (the magnitude of dust exposure) have been reflected by the bronchi pulmonary disease structure. The input of these dieseases into the occupational lung pathology has been significantly changed with the time course. Within first 18-20 years, pneumoconiosis was the only form of occupational lung pathology in the mine, whereas occupational bronchis and lung cancers were recorded within next then years thereafter. In cohorts of longest observation period, the average age of patients was increasingly ranked versus diseases as follows: silicosis, silicotuberculosis, chronic bronchitis, and lung cancer. (Author)

  1. Lithotrophic iron-oxidizing bacteria produce organic stalks to control mineral growth: implications for biosignature formation

    Energy Technology Data Exchange (ETDEWEB)

    Chan, Clara S; Fakra, Sirine C; Emerson, David; Fleming, Emily J; Edwards, Katrina J

    2011-07-01

    Neutrophilic Fe-oxidizing bacteria (FeOB) are often identified by their distinctive morphologies, such as the extracellular twisted ribbon-like stalks formed by Gallionella ferruginea or Mariprofundus ferrooxydans. Similar filaments preserved in silica are often identified as FeOB fossils in rocks. Although it is assumed that twisted iron stalks are indicative of FeOB, the stalk's metabolic role has not been established. To this end, we studied the marine FeOB M. ferrooxydans by light, X-ray and electron microscopy. Using time-lapse light microscopy, we observed cells excreting stalks during growth (averaging 2.2 {micro}m h(-1)). Scanning transmission X-ray microscopy and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy show that stalks are Fe(III)-rich, whereas cells are low in Fe. Transmission electron microscopy reveals that stalks are composed of several fibrils, which contain few-nanometer-sized iron oxyhydroxide crystals. Lepidocrocite crystals that nucleated on the fibril surface are much larger ({approx}100 nm), suggesting that mineral growth within fibrils is retarded, relative to sites surrounding fibrils. C and N 1s NEXAFS spectroscopy and fluorescence probing show that stalks primarily contain carboxyl-rich polysaccharides. On the basis of these results, we suggest a physiological model for Fe oxidation in which cells excrete oxidized Fe bound to organic polymers. These organic molecules retard mineral growth, preventing cell encrustation. This model describes an essential role for stalk formation in FeOB growth. We suggest that stalk-like morphologies observed in modern and ancient samples may be correlated confidently with the Fe-oxidizing metabolism as a robust biosignature.

  2. An Analysis of the Published Mineral Resource Estimates of the Haji-Gak Iron Deposit, Afghanistan

    International Nuclear Information System (INIS)

    Sutphin, David M.; Renaud, Karine M.; Drew, Lawrence J.

    2011-01-01

    The Haji-Gak iron deposit of eastern Bamyan Province, eastern Afghanistan, was studied extensively and resource calculations were made in the 1960s by Afghan and Russian geologists. Recalculation of the resource estimates verifies the original estimates for categories A (in-place resources known in detail), B (in-place resources known in moderate detail), and C 1 (in-place resources estimated on sparse data), totaling 110.8 Mt, or about 6% of the resources as being supportable for the methods used in the 1960s. C 2 (based on a loose exploration grid with little data) resources are based on one ore grade from one drill hole, and P 2 (prognosis) resources are based on field observations, field measurements, and an ore grade derived from averaging grades from three better sampled ore bodies. C 2 and P 2 resources are 1,659.1 Mt or about 94% of the total resources in the deposit. The vast P 2 resources have not been drilled or sampled to confirm their extent or quality. The purpose of this article is to independently evaluate the resources of the Haji-Gak iron deposit by using the available geologic and mineral resource information including geologic maps and cross sections, sampling data, and the analog-estimating techniques of the 1960s to determine the size and tenor of the deposit.

  3. Method for Transformation of Weakly Magnetic Minerals (Hematite, Goethite into Strongly Magnetic Mineral (Magnetite to Improve the Efficiency of Technologies for Oxidized Iron Ores Benefication

    Directory of Open Access Journals (Sweden)

    Ponomarenko, O.

    2015-03-01

    Full Text Available A new method for relatively simple transformation of weakly magnetic minerals (goethite (α-FeOOH and hematite (α-Fe2O3 into strongly magnetic mineral (magnetite (Fe3O4 was developed. It was shown, that transformation of structure and magnetic characteristics of go ethite and hematite are realized in the presence of starch at relatively low temperatures (in the range of 300—600 °С. Obtained results open up new possibilities for development of effective technologies for oxidized iron ore beneficiation.

  4. Effects of Radiation and a High Iron Load on Bone Mineral Density

    Science.gov (United States)

    Yuen, E.; Morgan, J. L. L.; Zwart, S. R.; Gonzales, E.; Camp, K.; Smith, S. M.; Bloomfield, S. A.

    2012-01-01

    Astronauts on long duration space flight missions to the moon or mars are exposed to radiation and have increase iron (Fe) stores, both of which can independently induce oxidative stress and may exacerbate bone mass loss and strength. We hypothesize a high Fe diet and a fractionated gamma radiation exposure would increase oxidative stress and lower bone mass. Three mo-old, SD rats (n=32) were randomized to receive an adequate Fe diet (45 mg Fe/kg diet) or a high Fe diet (650 mg Fe/kg diet) for 4 wks and either a cumulative 3 Gy dose (fractionated 8 x 0.375 Gy) of gamma radiation (Cs-137) or sham exposure starting on day 14. Elisa kit assessed serum catalase, clinical analyzer assessed serum Fe status and ex vivo pQCT scans measured bone parameters in the proximal/midshaft tibia and femoral neck. Mechanical strength was assessed by 3-pt bending and femoral neck test. There is a significant decrease in trabecular bone mineral density (BMD) from radiation (p less than 0.05) and a trend in diet (p=0.05) at the proximal tibia. There is a significant interaction in cortical BMD from the combined treatments at the midshaft tibia (p less than 0.05). There is a trending decrease in total BMD from diet (p=0.07) at the femoral neck. In addition, high serum Fe was correlated to low trabecular BMD (p less than 0.05) and high serum catalase was correlated to low BMD at all 3 bone sites (p less than 0.05). There was no difference in the max load of the tibia or femoral neck. Radiation and a high iron diet increases iron status and catalase in the serum and decreases BMD.

  5. Iron and manganese shuttles control the formation of authigenic phosphorus minerals in the euxinic basins of the Baltic Sea

    NARCIS (Netherlands)

    Jilbert, T.|info:eu-repo/dai/nl/304835714; Slomp, C.P.|info:eu-repo/dai/nl/159424003

    2013-01-01

    Microanalysis of epoxy resin-embedded sediments is used to demonstrate the presence of authigenic iron (Fe) (II) phosphates and manganese (Mn)-calcium (Ca)-carbonate-phosphates in the deep euxinic basins of the Baltic Sea. These minerals constitute major burial phases of phosphorus (P) in this area,

  6. Iron, zinc and phytic acid in rice from China: wet and dry processing towards improved mineral bioavailability

    NARCIS (Netherlands)

    Liang, J.

    2007-01-01

    Rice and rice products supply two thirds of Chinese people with their staple food. Mineral deficiencies, especially of iron and zinc, are prevalent in China, and are caused by insufficient intake and poor bioavailability. Rice and rice products contribute more than 50% of the antinutrient phytic

  7. Neutrino energy loss rates due to key iron isotopes for core-collapse physics

    International Nuclear Information System (INIS)

    Nabi, J.-U.

    2008-07-01

    Accurate estimates of neutrino energy loss rates are needed for the study of the late stages of the stellar evolution, in particular for the cooling of neutron stars and white dwarfs. The energy spectra of neutrinos and antineutrinos arriving at the Earth can also provide useful information on the primary neutrino fluxes as well as neutrino mixing scenario. Proton-neutron quasi-particle random phase approximation (pn-QRPA) theory has recently being used for a microscopic calculation of stellar weak interaction rates of fp-shell nuclide, particularly iron isotopes, with success. Here I present the calculation of neutrino and antineutrino energy loss rates due to key iron isotopes in stellar matter using the pn-QRPA theory. The rates are calculated on a fine grid of temperature-density scale suitable for core-collapse simulators. The calculated rates are compared against earlier calculations. The neutrino cooling rates due to even-even isotopes of iron, 54,56 Fe, are in good agreement with the rates calculated using the large-scale shell model. The pn-QRPA calculated neutrino energy loss rates due to 55 Fe are enhanced roughly around an order of magnitude compared to the large-scale shell model calculation during the oxygen and silicon shell burning stages of massive stars and favor a lower entropy for the cores of massive stars. (author)

  8. Soil phosphorus redistribution among iron-bearing minerals under redox fluctuation

    Science.gov (United States)

    Lin, Y.; Bhattacharyya, A.; Campbell, A.; Nico, P. S.; Pett-Ridge, J.; Silver, W. L.

    2016-12-01

    Phosphorus (P) is a key limiting nutrient in tropical forests that governs primary production, litter decomposition, and soil respiration. A large proportion of P in these highly weathered soils is bound to short-range ordered or poorly crystalline iron (Fe) minerals. It is well-documented that these Fe minerals are redox-sensitive; however, little is known about how Fe-redox interactions affect soil P turnover. We evaluated the impacts of oxic/anoxic fluctuation on soil P fractions and reactive Fe species in a laboratory incubation experiment. Soils from a humid tropical forest were amended with plant biomass and incubated for up to 44 days under four redox regimes: static oxic, static anoxic, high frequency fluctuating (4-day oxic/4-day anoxic), and low frequency fluctuating (8-day oxic/4-day anoxic). We found that the static anoxic treatment induced a 10-fold increase in Fe(II) (extracted by hydrochloric acid) and a 1.5-fold increase in poorly crystalline Fe (extracted by ammonium oxalate), suggesting that anoxic conditions drastically increased Fe(III) reduction and the formation of amorphous Fe minerals. Static anoxic conditions also increased Fe-bound P (extracted by sodium hydroxide) and increased the oxalate-extractable P by up to 110% relative to static oxic conditions. In two fluctuating treatments, Fe(II) and oxalate-extractable Fe and P were all increased by short-term reduction events after 30 minutes, but fell back to their initial levels after 3 hours. These results suggest that reductive dissolution of Fe(III) minerals mobilized a significant amount of P; however, this P could be rapidly re-adsorbed. Furthermore, bioavailable P extracted by sodium bicarbonate solution was largely unaffected by redox regimes and was only increased by static anoxic conditions after 20 days. Overall, our data demonstrate that a significant amount of soil P may be liberated and re-adsorbed by Fe minerals during redox fluctuation. Even though bioavailable P appears to be

  9. Minerals

    Science.gov (United States)

    Minerals are important for your body to stay healthy. Your body uses minerals for many different jobs, including keeping your bones, muscles, heart, and brain working properly. Minerals are also important for making enzymes and hormones. ...

  10. "Conjugate channeling" effect in dislocation core diffusion: carbon transport in dislocated BCC iron.

    Science.gov (United States)

    Ishii, Akio; Li, Ju; Ogata, Shigenobu

    2013-01-01

    Dislocation pipe diffusion seems to be a well-established phenomenon. Here we demonstrate an unexpected effect, that the migration of interstitials such as carbon in iron may be accelerated not in the dislocation line direction ξ, but in a conjugate diffusion direction. This accelerated random walk arises from a simple crystallographic channeling effect. c is a function of the Burgers vector b, but not ξ, thus a dislocation loop possesses the same everywhere. Using molecular dynamics and accelerated dynamics simulations, we further show that such dislocation-core-coupled carbon diffusion in iron has temperature-dependent activation enthalpy like a fragile glass. The 71° mixed dislocation is the only case in which we see straightforward pipe diffusion that does not depend on dislocation mobility.

  11. Mineral and chemical composition of rock core and surface gas composition in Horonobe Underground Research Laboratory project. Phase 1

    International Nuclear Information System (INIS)

    Hiraga, Naoto; Ishii, Eiichi

    2008-02-01

    The following three kinds of analyses were conducted for the 1st phase of the Horonobe Underground Research Laboratory Project. Mineral composition analysis of core sample. Whole rock chemical composition analysis of core sample. Surface gas composition analysis. This document summarizes the results of these analyses. (author)

  12. Lulak Abad Iron Occurrence, Northwest of Zanjan: Metamorphosed and Deformed Volcano-Sedimentary Type of Mineralization in Central Iran

    Directory of Open Access Journals (Sweden)

    Mehri Karami

    2016-07-01

    Full Text Available Keywords: Iron mineralization, hydrothermal vein, alteration, Lulak Abad, Zanjan, Central Iran Introduction The Lulak Abad iron occurrence is located in the northwestern part of the Central Iran, 55 km west of Zanjan. Mineralization at the Lulak Abad area was originally identified by Zamin Gostar Company (2007, during a geophysical exploration. The present paper provides an overview of the geological framework, the mineralization characteristics, and the results of a geochemical study of the Lulak Abad iron occurrence with an application to the ore genesis. Identification of these characteristics can be used as a model for exploration of this type of iron mineralization in the Central Iran and elsewhere. Materials and methods Detailed field work was carried out at different scales (give scales in parentheses in the Lulak Abad area. About 16 polished thin and thin sections from host rocks and mineralized and altered zones were studied by conventional petrographic and mineralogical methods at the Department of Geology, University of Zanjan. In addition, a total of 7 samples from ore zones at the Lulak Abad occurrence were analyzed by ICP-OES for minor and trace elements and REE compositions at Geological Survey of Iran, Tehran, Iran. Result Rock units exposed in the Lulak Abad area consist of schists and metavolcanic units the Kahar Formation; Lotfi, 2001 that were intruded by granite and microdiorite bodies. The schist units consist of chlorite-biotite-muscovite schist and muscovite schist that show granolepidoblastic texture with foliation-parallel disseminated magnetite. The metavolcanic units consist of metadacite, rhyolitic metatuff and meta-andesite with porphyritic textures. They are marked by dominant mylonitic foliation surrounding feldspar and quartz porphyroclasts. Alkali feldspar and quartz are the principal minerals of the granite. The intrusion is characterized by intense deformation features and is highly mylonitized. Based on field

  13. Characterization of iron and manganese minerals and their associated microbiota in different mine sites to reveal the potential interactions of microbiota with mineral formation.

    Science.gov (United States)

    Park, Jin Hee; Kim, Bong-Soo; Chon, Chul-Min

    2018-01-01

    Different environmental conditions such as pH and dissolved elements of mine stream induce precipitation of different minerals and their associated microbial community may vary. Therefore, mine precipitates from various environmental conditions were collected and their associated microbiota were analyzed through metagenomic DNA sequencing. Various Fe and Mn minerals including ferrihydrite, schwertmannite, goethite, birnessite, and Mn-substituted δ-FeOOH (δ-(Fe 1-x , Mn x )OOH) were found in the different environmental conditions. The Fe and Mn minerals were enriched with toxic metal(loid)s including As, Cd, Ni and Zn, indicating they can act as scavengers of toxic metal(loid)s in mine streams. Under acidic conditions, Acidobacteria was dominant phylum and Gallionella (Fe oxidizing bacteria) was the predominant genus in these Fe rich environments. Manganese oxidizing bacteria, Hyphomicrobium, was found in birnessite forming environments. Leptolyngbya within Cyanobacteria was found in Fe and Mn oxidizing environments, and might contribute to Fe and Mn oxidation through the production of molecular oxygen. The potential interaction of microbial community with minerals in mine sites can be traced by analysis of microbial community in different Fe and Mn mineral forming environments. Iron and Mn minerals contribute to the removal of toxic metal(loid)s from mine water. Therefore, the understanding characteristics of mine precipitates and their associated microbes helps to develop strategies for the management of contaminated mine water. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Delivery of anthropogenic bioavailable iron from mineral dust and combustion aerosols to the ocean

    Directory of Open Access Journals (Sweden)

    A. Ito

    2016-01-01

    Full Text Available Atmospheric deposition of anthropogenic soluble iron (Fe to the ocean has been suggested to modulate primary ocean productivity and thus indirectly affect the climate. A key process contributing to anthropogenic sources of soluble Fe is associated with air pollution, which acidifies Fe-containing mineral aerosols during their transport and leads to Fe transformation from insoluble to soluble forms. However, there is large uncertainty in our estimate of this anthropogenic soluble Fe. In this study, for the first time, we interactively combined laboratory kinetic experiments with global aerosol modeling to more accurately quantify anthropogenic soluble Fe due to air pollution. Firstly, we determined Fe dissolution kinetics of African dust samples at acidic pH values with and without ionic species commonly found in aerosol water (i.e., sulfate and oxalate. Then, by using acidity as a master variable, we constructed a new empirical scheme for Fe release from mineral dust due to inorganic and organic anions in aerosol water. We implemented this new scheme and applied an updated mineralogical emission database in a global atmospheric chemistry transport model to estimate the atmospheric concentration and deposition flux of soluble Fe under preindustrial and modern conditions. Our improved model successfully captured the inverse relationship of Fe solubility and total Fe loading measured over the North Atlantic Ocean (i.e., 1–2 orders of magnitude lower Fe solubility in northern-African- than combustion-influenced aerosols. The model results show a positive relationship between Fe solubility and water-soluble organic carbon (WSOC/Fe molar ratio, which is consistent with previous field measurements. We estimated that deposition of soluble Fe to the ocean increased from 0.05–0.07 Tg Fe yr−1 in the preindustrial era to 0.11–0.12 Tg Fe yr−1 in the present day, due to air pollution. Over the high-nitrate, low-chlorophyll (HNLC regions

  15. Evaluation of Digital Classification of Polarimetric SAR Data for Iron-Mineralized Laterites Mapping in the Amazon Region

    Directory of Open Access Journals (Sweden)

    Cleber G. Oliveira

    2013-06-01

    Full Text Available This study evaluates the potential of C- and L-band polarimetric SAR data for the discrimination of iron-mineralized laterites in the Brazilian Amazon region. The study area is the N1 plateau located on the northern border of the Carajás Mineral Province, the most important Brazilian mineral province which has numerous mineral deposits, particularly the world’s largest iron deposits. The plateau is covered by low-density savanna-type vegetation (campus rupestres which contrasts visibly with the dense equatorial forest. The laterites are subdivided into three units: chemical crust, iron-ore duricrust, and hematite, of which only the latter two are of economic interest. Full polarimetric data from the airborne R99B sensor of the SIVAM/CENSIPAM (L-band system and the RADARSAT-2 satellite (C-band were evaluated. The study focused on an assessment of distinct schemes for digital classification based on decomposition theory and hybrid approach, which incorporates statistical analysis as input data derived from the target decomposition modeling. The results indicated that the polarimetric classifications presented a poor performance, with global Kappa values below 0.20. The accuracy for the identification of units of economic interest varied from 55% to 89%, albeit with high commission error values. In addition, the results using L-band were considered superior compared to C-band, which suggest that the roughness scale for laterite discrimination in the area is nearer to L than to C-band.

  16. Charge state mapping of mixed valent iron and manganese mineral particles using Scanning Transmission X-ray Microscopy (STXM)

    International Nuclear Information System (INIS)

    Pecher, K.; Nealson, K.; Kneedler, E.; Rothe, J.; Meigs, G.; Warwick, T.; Tonner, B.

    2000-01-01

    The interfaces between solid mineral particles and water play a crucial role in partitioning and chemical transformation of many inorganic as well as organic pollutants in environmental systems. Among environmentally significant minerals, mixed-valent oxides and hydroxides of iron (e.g. magnetite, green rusts) and manganese (hausmanite, birnessite) have been recognized as particularly strong sorbents for metal ions. In addition, minerals containing Fe(II) have recently been proven to be powerful reductants for a wide range of pollutants. Chemical properties of these minerals strongly depend on the distribution and availability of reactive sites and little is known quantitatively about the nature of these sites. We have investigated the bulk distribution of charge states of manganese (Mn (II, III, IV)) and iron (Fe(II, III)) in single particles of natural manganese nodules and synthetic green rusts using Scanning Transmission X-ray SpectroMicroscopy (STXM). Pixel resolved spectra (XANES) extracted from stacks of images taken at different wave lengths across the metal absorption edge were fitted to total electron yield (TEY) spectra of single valent reference compounds. Two dimensional maps of bulk charge state distributions clearly reveal domains of different oxidation states within single particles of Mn-nodules and green rust precipitates. Changes of oxidation states of iron were followed as a result of reductive transformation of an environmental contaminant (CCl 4 ) using green rust as the only reductant

  17. Iron-Coupled Anaerobic Oxidation of Methane Performed by a Mixed Bacterial-Archaeal Community Based on Poorly Reactive Minerals.

    Science.gov (United States)

    Bar-Or, Itay; Elvert, Marcus; Eckert, Werner; Kushmaro, Ariel; Vigderovich, Hanni; Zhu, Qingzeng; Ben-Dov, Eitan; Sivan, Orit

    2017-11-07

    Anaerobic oxidation of methane (AOM) was shown to reduce methane emissions by over 50% in freshwater systems, its main natural contributor to the atmosphere. In these environments iron oxides can become main agents for AOM, but the underlying mechanism for this process has remained enigmatic. By conducting anoxic slurry incubations with lake sediments amended with 13 C-labeled methane and naturally abundant iron oxides the process was evidenced by significant 13 C-enrichment of the dissolved inorganic carbon pool and most pronounced when poorly reactive iron minerals such as magnetite and hematite were applied. Methane incorporation into biomass was apparent by strong uptake of 13 C into fatty acids indicative of methanotrophic bacteria, associated with increasing copy numbers of the functional methane monooxygenase pmoA gene. Archaea were not directly involved in full methane oxidation, but their crucial participation, likely being mediators in electron transfer, was indicated by specific inhibition of their activity that fully stopped iron-coupled AOM. By contrast, inhibition of sulfur cycling increased 13 C-methane turnover, pointing to sulfur species involvement in a competing process. Our findings suggest that the mechanism of iron-coupled AOM is accomplished by a complex microbe-mineral reaction network, being likely representative of many similar but hidden interactions sustaining life under highly reducing low energy conditions.

  18. Effect of different iron compounds on rheological and technological parameters as well as bioaccessibility of minerals in whole wheat bread.

    Science.gov (United States)

    Rebellato, Ana Paula; Bussi, Jéssica; Silva, Joyce Grazielle Siqueira; Greiner, Ralf; Steel, Caroline Joy; Pallone, Juliana Azevedo Lima

    2017-04-01

    This study aimed at investigating the effect of iron compounds used in whole wheat flour (WWF) fortification, both on rheological properties of the dough and on bread technological quality. Furthermore, bioaccessibility of iron (Fe), zinc (Zn) and calcium (Ca) in the final breads was determined. Rheological properties (mainly dough development time, stability, mixing tolerance index, resistance to extension and ratio number) of the dough and the technological quality of bread (mainly oven spring and cut opening) were altered. However, producing roll breads fortified with different iron compounds was still possible. NaFeEDTA (ferric sodium ethylene diamine tetra acetic acid) proved to be the most effective iron compound in the fortification of WWF, since it presented the highest levels of solubility (44.80%) and dialysability (46.14%), followed by microencapsulated ferrous fumarate (FFm). On the other hand, the microencapsulated ferrous sulfate (FSm) and reduced iron presented the lowest solubility (5.40 and 18.30%, respectively) and dialysability (33.12 and 31.79%, respectively). Zn dialysis was positively influenced by NaFeEDTA, FSm, and ferrous fumarate. As for Ca, dialysis was positively influenced by FSm and negatively influenced by FFm. The data indicated that there is a competitive interaction for the absorption of these minerals in whole wheat roll breads, but all studied minerals can be considered bioaccessible. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Gold nanorod@iron oxide core-shell heterostructures: synthesis, characterization, and photocatalytic performance.

    Science.gov (United States)

    Li, Yue; Zhao, Junwei; You, Wenlong; Cheng, Danhong; Ni, Weihai

    2017-03-17

    Iron oxides are directly coated on the surface of cetyl-trimethylammonium bromide (CTAB)-capped gold nanorods (AuNRs) in aqueous solutions at room temperature, which results in AuNR@Fe 2 O 3 , AuNR@Fe 3 O 4 , and AuNR@Fe 2 O 3 @Fe 3 O 4 core-shell heterostructures. The iron oxide shells are uniform, smooth, with characteristic porous structure, and their thickness can be readily tuned. The shell formation is highly dependent on the reaction parameters including pH and CTAB concentration. The Fe 2 O 3 shell is amorphous and exhibits nearly zero remanence and coercivity, while the Fe 3 O 4 shell is ferromagnetic with a low saturation magnetization of about 0.5 emu g -1 due to its low crystallinity and the porous structure. At elevated temperatures achieved by plasmonic heating of the Au core, the Fe 2 O 3 shell transforms from amorphous to γ-Fe 2 O 3 and α-Fe 2 O 3 phases, while the Fe 3 O 4 phase disappears because of the oxidation of Fe 2+ . A 1.4-fold increase of photocatalytic performance is observed due to the plasmonic resonance provided by the Au core. The photocatalytic efficiency of Fe 3 O 4 is about 1.7-fold higher than Fe 2 O 3 as more surface defects are present on the Fe 3 O 4 shell, promoting the adsorption and activation of reagents on the surface during the catalytic reactions. This approach can be readily extended to other nanostructures including Au spherical nanoparticles and nanostars. These highly uniform and multifunctional core-shell heterostructures can be of great potential in a variety of energy, magnetic, and environment applications.

  20. Moessbauer study of the evolution of a laterite iron mineral based catalyst: effect of the activation treatment

    International Nuclear Information System (INIS)

    Cubeiro, M.L.; Goldwasser, M.R.; Perez Zurita, M.J.; Franco, C.; Gonzalez-Jimenez, F.; Jaimes, E.

    1994-01-01

    The syngas reaction has been studied using a laterite iron mineral, promoted with K and Mn. In situ activation under syngas, as well as pre-treatment with H 2 followed by CO under mild and more severe conditions were tested. These activation procedures led to different iron phase compositions and to different catalytic selectivities. The C 2 -C 4 /CH 4 ratio was significantly lower for those catalysts which after reaction showed the presence of hexagonal carbide and magnetite compared to the solid, which showed the highest proportion of Haegg carbide. (orig.)

  1. Hydrothermal titanite from the Chengchao iron skarn deposit: temporal constraints on iron mineralization, and its potential as a reference material for titanite U-Pb dating

    Science.gov (United States)

    Hu, Hao; Li, Jian-Wei; McFarlane, Christopher R. M.

    2017-09-01

    Uranium-lead isotopes and trace elements of titanite from the Chengchao iron skarn deposit (Daye district, Eastern China), located along the contact zones between Triassic marine carbonates and an early Cretaceous intrusive complex consisting of granite and quartz diorite, were analyzed using laser ablation inductively coupled plasma mass spectrometry to provide temporal constraints on iron mineralization and to evaluate its potential as a reference material for titanite U-Pb geochronology. Titanite grains from mineralized endoskarn have simple growth zoning patterns, exhibit intergrowth with magnetite, diopside, K-feldspar, albite and actinolite, and typically contain abundant primary two-phase fluid inclusions. These paragenetic and textural features suggest that these titanite grains are of hydrothermal origin. Hydrothermal titanite is distinct from the magmatic variety from the ore-related granitic intrusion in that it contains unusually high concentrations of U (up to 2995 ppm), low levels of Th (12.5-453 ppm), and virtually no common Pb. The REE concentrations are much lower, as are the Th/U and Lu/Hf ratios. The hydrothermal titanite grains yield reproducible uncorrected U-Pb ages ranging from 129.7 ± 0.7 to 132.1 ± 2.7 Ma (2σ), with a weighted mean of 131.2 ± 0.2 Ma [mean standard weighted deviation (MSWD) = 1.7] that is interpreted as the timing of iron skarn mineralization. This age closely corresponds to the zircon U-Pb age of 130.9 ± 0.7 Ma (MSWD = 0.7) determined for the quartz diorite, and the U-Pb ages for zircon and titanite (130.1 ± 1.0 Ma and 131.3 ± 0.3 Ma) in the granite, confirming a close temporal and likely genetic relationship between granitic magmatism and iron mineralization. Different hydrothermal titanite grains have virtually identical uncorrected U-Pb ratios suggestive of negligible common Pb in the mineral. The homogeneous textures and U-Pb characteristics of Chengchao hydrothermal titanite suggest that the mineral might be a

  2. Measurement of net nitrogen and phosphorus mineralization in wetland soils using a modification of the resin-core technique

    Science.gov (United States)

    Noe, Gregory B.

    2011-01-01

    A modification of the resin-core method was developed and tested for measuring in situ soil N and P net mineralization rates in wetland soils where temporal variation in bidirectional vertical water movement and saturation can complicate measurement. The modified design includes three mixed-bed ion-exchange resin bags located above and three resin bags located below soil incubating inside a core tube. The two inner resin bags adjacent to the soil capture NH4+, NO3-, and soluble reactive phosphorus (SRP) transported out of the soil during incubation; the two outer resin bags remove inorganic nutrients transported into the modified resin core; and the two middle resin bags serve as quality-control checks on the function of the inner and outer resin bags. Modified resin cores were incubated monthly for a year along the hydrogeomorphic gradient through a floodplain wetland. Only small amounts of NH4+, NO3-, and SRP were found in the two middle resin bags, indicating that the modified resin-core design was effective. Soil moisture and pH inside the modified resin cores typically tracked changes in the surrounding soil abiotic environment. In contrast, use of the closed polyethylene bag method provided substantially different net P and N mineralization rates than modified resin cores and did not track changes in soil moisture or pH. Net ammonification, nitrifi cation, N mineralization, and P mineralization rates measured using modified resin cores varied through space and time associated with hydrologic, geomorphic, and climatic gradients in the floodplain wetland. The modified resin-core technique successfully characterized spatiotemporal variation of net mineralization fluxes in situ and is a viable technique for assessing soil nutrient availability and developing ecosystem budgets.

  3. Investigation on type and origin of iron mineralization at Mesgar occurrence, south of Zanjan, using petrological, mineralogical and geochemical data

    Directory of Open Access Journals (Sweden)

    Mohammad Ebrahimi

    2015-04-01

    Full Text Available Introduction Mesgar iron occurrence is located in northwestern part of the Central Iran, 115 km south of Zanjan. Although there is a sequence of volcanic-pyroclastic rocks accompanied by iron mineralization, no detailed works had been conducted in the area. The present paper provides an overview of the geological framework, the mineralization characteristics, and the results of geochemical study of the Mesgar iron occurrence with an application to the ore genesis. Identification of these characteristics can be used as a model for exploration of this type of iron mineralization in the Central Iran and elsewhere. Materials and methods Detailed field work has been carried out at different scales in the Mesgar area. About 16 polished thin and thin sections from host rocks and mineralized and altered zones were studied by conventional petrographic and mineralogic methods at the Department of Geology, University of Zanjan. In addition, a total of 3 samples from least-altered volcanic host rocks and 2 samples from ore zones from the Mesgar occurrence were analyzed by ICP-MS and ICP-OES for whole-rock major and trace elements and REE compositions at the Zarazma Laboratories, Tehran, Iran. Results and Discussion Based on field observation, rock units exposed in the Mesgar area consist of Miocene sedimentary rocks and volcanic-pyroclastic units (Rādfar et al., 2005. The pyroclastic units consist of volcanic breccia and agglomerate. They lie concordantly on the Miocene sedimentary units, and are in turn concordantly overlain by andesitic basalt lavas. The lavas show porphyritic texture consisting of plagioclase (up to 3 mm in size and pyroxene phenocrysts set in a fine-grained to glassy groundmass. Seriate, cumulophyric, glomeroporphyritic and trachytic textures are also observed. Iron mineralization occurs as vein and lens-shaped bodies within and along the contacts of pyroclastic (footwall and andesitic basalt lavas (hanging wall. The veins reach up to

  4. Mineral chemical and petrographic occurrences os iron of the south east of Uruguay (Nico Pere z terrane)

    International Nuclear Information System (INIS)

    Oyhantcabal, P.; Sanchez Bettucci, L.; Siegesmund, S.; Pineyro, D.

    2007-01-01

    Two iron-formation deposits from S E Uruguay were petrographic ally and mineralogically investigated (including microprobe mineral chemistry). The deposit from Piedra de Gigante (ANCAP) quarry is related to tectonic slivers of a platform succession in ortho gneiss of ca. 1750 Ma. Data of detrital zircon in this platform succession point to Meso- to Neo proterozoic age.The iron deposit of Piedra del Gigante (ANCAP) quarry belongs to a succession of mica schists, quartz-muscovite schists, marbles and basic rocks. Magnetite rich layers alternate with banded rocks rich in hematite, carbonate and amphibole. Carbonate is dolomite (Mg0.7Ca1.08Mn0.05Fe0.11(CO3)2) and the amphibole is a pale green tremolite (Na0,18Ca1,68Mn0,07Mg4,16Fe+++0,2Fe++0,55Al0,03(Si7,86Al0,13)O22(OH)2). This iron deposit shows strong deformation associated with martitization of magnetite and formation of specularite rich layers where relicts of magnetite (partly martitized) are occasionally observed. Available data are not conclusive about the genesis. The low iron-content of the amphibole together with dolomite in the mineral association cast doubts on a BIF-type origin, but low contents of Al2O3, V2O3, MnO and ZnO in magnetite do not indicate an igneous origin. High oxygen fugacity during martitization in medium-T metamorphic conditions could have determined that iron rich amphiboles were not formed as is normally expected in iron-formations. In the outcrop of Cerro la Higuerita (Grupo Arroyo del Soldado; Ediacaran) a succession of metapelites (bottom), iron rich pelites and iron formations (top) is observed. The metapelites contain evidences of volcanic contribution (phenochrysts of quartz and alkali feldspar as well as shards in the matrix) suggesting a volcanic source for the iron. This iron-formation contains magnetite pheno blasts (partly martitized) and fine disseminated laths of hematite in the matrix, together with grunerite (Na0,04Ca0,17 Mn0,02Mg1,36Fe5,35Al0,07(Si7,97Al0,03)O22(OH)2

  5. Influence of non-clay minerals on the interaction between metallic iron and Callovo-Oxfordian clay fraction

    International Nuclear Information System (INIS)

    Rivard, C.; Pelletier, M.; Villieras, F.; Michau, N.

    2012-01-01

    Document available in extended abstract form only. In the context of the geological disposal of high-level radioactive waste, it is of prime importance to understand the interaction mechanisms between the geological matrix, Callovo-Oxfordian clay rock (COx) and metallic iron, from the package overpack. In order to evidence the individual role of each clay component entering in the mineralogy of the COx, interactions between metallic iron and pure clays (smectites, illite and kaolinite) were first conducted. To investigate the role of the other minerals, the reactivity of COx, COx clay fraction (COxCF) and mixtures between COxCF and quartz, calcite or pyrite, was studied. Clays and additional minerals were put in contact with powder metallic iron with a weight ratio iron:clay fixed at 1:3 and a clay:solution ratio of 1:20. Proportions of non-clay minerals were deduced from the average COx composition: 50% clays, 24.5% quartz, 24.5% calcite and 1% pyrite. Batch experiments were carried out in anoxic conditions at 90 deg. C in the presence of background electrolyte (NaCl 0.02 M.L -1 , CaCl 2 0.04 M.L -1 ) in Parr reactors for durations of one, three or nine months. After reaction, solid and liquid phases were separated by centrifugation and characterized by classical techniques combining chemical analyses (liquid analyses, transmission electron microscopy combined with Energy Dispersive of X-rays spectroscopy TEM-EDS), mineralogical (X-ray diffraction), spectroscopic ( 57 Fe Moessbauer) and morphometric techniques (TEM, scanning electron microscopy and N 2 adsorption). For COx, COxCF and all the pure clay phases, major evolutions were observed during the first month, which shows that the oxidation of metallic iron is rapid in our experimental conditions. Release of iron cations in solution, pH increase (8-10) and Eh decrease (reductive conditions) are responsible for the partial dissolution of initial clay phases. Released iron is involved in the crystallization of Fe

  6. Influence of particle size and mineral phase in the analysis of iron ore slurries by Laser-Induced Breakdown Spectroscopy

    International Nuclear Information System (INIS)

    Michaud, Daniel; Leclerc, Remi; Proulx, Eric

    2007-01-01

    Laser-Induced Breakdown Spectroscopy (LIBS) was applied to the analysis of iron ore concentrates. The objective was to determine the influence of particle size and mineral phase on the LIBS signal. The LIBS spectra of hematite and magnetite ore concentrates were qualitatively indistinguishable from each other but magnetite yielded systematically less than hematite. This behavior could be set into an empirical equation to correct the iron peak intensities according to the level of magnetite in the analyzed sample. Similarly, an increase of the LIBS signal was observed as the particle size of the ore samples decreased. Again, an equation could be written down to correct the intensity of either iron or silicon in response to a variation of the average particle size of the ore concentrate. Using these corrections, proper response of the silicon signal against the concentration of silica in the samples was restored. The observed dependence of the strength of the iron signal upon the mineral phase is attributed to oxidation of magnetite into hematite

  7. High dose intravenous iron, mineral homeostasis and intact FGF23 in normal and uremic rats

    DEFF Research Database (Denmark)

    Gravesen, Eva; Hofman-Bang, Jacob; Mace, Maria L.

    2013-01-01

    High iron load might have a number of toxic effects in the organism. Recently intravenous (iv) iron has been proposed to induce elevation of fibroblast growth factor 23 (FGF23), hypophosphatemia and osteomalacia in iron deficient subjects. High levels of FGF23 are associated with increased...

  8. Iron oxide minerals in dust of the Red Dawn event in eastern Australia, September 2009

    Science.gov (United States)

    Reynolds, Richard L.; Cattle, Stephen R.; Moskowitz, Bruce M.; Goldstein, Harland L.; Yauk, Kimberly; Flagg, Cody B.; Berquó, Thelma S.; Kokaly, Raymond F.; Morman, Suzette A.; Breit, George N.

    2014-01-01

    Iron oxide minerals typically compose only a few weight percent of bulk atmospheric dust but are important for potential roles in forcing climate, affecting cloud properties, influencing rates of snow and ice melt, and fertilizing marine phytoplankton. Dust samples collected from locations across eastern Australia (Lake Cowal, Orange, Hornsby, and Sydney) following the spectacular “Red Dawn” dust storm on 23 September 2009 enabled study of the dust iron oxide assemblage using a combination of magnetic measurements, Mössbauer spectroscopy, reflectance spectroscopy, and scanning electron microscopy. Red Dawn was the worst dust storm to have hit the city of Sydney in more than 60 years, and it also deposited dust into the Tasman Sea and onto snow cover in New Zealand. Magnetization measurements from 20 to 400 K reveal that hematite, goethite, and trace amounts of magnetite are present in all samples. Magnetite concentrations (as much as 0.29 wt%) were much higher in eastern, urban sites than in western, agricultural sites in central New South Wales (0.01 wt%), strongly suggesting addition of magnetite from local urban sources. Variable temperature Mössbauer spectroscopy (300 and 4.2 K) indicates that goethite and hematite compose approximately 25–45% of the Fe-bearing phases in samples from the inland sites of Orange and Lake Cowal. Hematite was observed at both temperatures but goethite only at 4.2 K, thereby revealing the presence of nanogoethite (less than about 20 nm). Similarly, hematite particulate matter is very small (some of it d < 100 nm) on the basis of magnetic results and Mössbauer spectra. The degree to which ferric oxide in these samples might absorb solar radiation is estimated by comparing reflectance values with a magnetic parameter (hard isothermal remanent magnetization, HIRM) for ferric oxide abundance. Average visible reflectance and HIRM are correlated as a group (r2 = 0.24), indicating that Red Dawn ferric oxides have

  9. Core Formation on Asteroid 4 Vesta: Iron Rain in a Silicate Magma Ocean

    Science.gov (United States)

    Kiefer, Walter S.; Mittlefehldt, David W.

    2017-01-01

    Geochemical observations of the eucrite and diogenite meteorites, together with observations made by NASA's Dawn spacecraft, suggest that Vesta resembles H chondrites in bulk chemical composition, possibly with about 25% of a CM-chondrite like composition added in. For this model, the core is 15% by mass (or 8 volume %) of the asteroid. The abundances of moderately siderophile elements (Ni, Co, Mo, W, and P) in eucrites require that essentially all of the metallic phase in Vesta segregated to form a core prior to eucrite solidification. Melting in the Fe-Ni-S system begins at a cotectic temperature of 940 deg. C. Only about 40% of the total metal phase, or 3-4 volume % of Vesta, melts prior to the onset of silicate melting. Liquid iron in solid silicate initially forms isolated pockets of melt; connected melt channels, which are necessary if the metal is to segregate from the silicate, are only possible when the metal phase exceeds about 5 volume %. Thus, metal segregation to form a core does not occur prior to the onset of silicate melting.

  10. Differentiation of Asteroid 4 Vesta: Core Formation by Iron Rain in a Silicate Magma Ocean

    Science.gov (United States)

    Kiefer, Walter S.; Mittlefehldt, David W.

    2017-01-01

    Geochemical observations of the eucrite and diogenite meteorites, together with observations made by NASA's Dawn spacecraft while orbiting asteroid 4 Vesta, suggest that Vesta resembles H chondrites in bulk chemical composition, possible with about 25 percent of a CM-chondrite like composition added in. For this model, the core is 15 percent by mass (or 8 percent by volume) of the asteroid, with a composition of 73.7 percent by weight Fe, 16.0 percent by weight S, and 10.3 percent by weight Ni. The abundances of moderately siderophile elements (Ni, Co, Mo, W, and P) in eucrites require that essentially all of the metallic phase in Vesta segregated to form a core prior to eucrite solidification. The combination of the melting phase relationships for the silicate and metal phases, together with the moderately siderophile element concentrations together require that complete melting of the metal phase occurred (temperature is greater than1350 degrees Centigrade), along with substantial (greater than 40 percent) melting of the silicate material. Thus, core formation on Vesta occurs as iron rain sinking through a silicate magma ocean.

  11. Removal of Iron and Manganese from Natural Groundwater by Continuous Reactor Using Activated and Natural Mordenite Mineral Adsorption

    Science.gov (United States)

    Zevi, Y.; Dewita, S.; Aghasa, A.; Dwinandha, D.

    2018-01-01

    Mordenite minerals derived from Sukabumi natural green stone founded in Indonesia was tested in order to remove iron and manganese from natural groundwater. This research used two types of adsorbents which were consisted of physically activated and natural mordenite. Physical activation of the mordenite was carried out by heating at 400-600°C for two hours. Batch system experiments was also conducted as a preliminary experiment. Batch system proved that both activated and natural mordenite minerals were capable of reducing iron and manganese concentration from natural groundwater. Then, continuous experiment was conducted using down-flow system with 45 ml/minute of constant flow rate. The iron & manganese removal efficiency using continuous reactor for physically activated and natural mordenite were 1.38-1.99%/minute & 0.8-1.49%/minute and 2.26%/minute & 1.37-2.26%/minute respectively. In addition, the regeneration treatment using NH4Cl solution managed to improve the removal efficiency of iron & manganese to 1.98%/minute & 1.77-1.90%/minute and 2.25%/minute & 2.02-2.21%/minute on physically activated mordenite and natural mordenite respectively. Subsequently, the activation of the new mordenite was carried out by immersing mordenite in NH4Cl solution. This chemical activation showed 2.42-2.75%/minute & 0.96 - 2.67 %/minute and 2.66 - 2.78 %/minute & 1.34 - 2.32 %/minute of iron & manganese removal efficiency per detention time for chemically activated and natural mordenite respectively.

  12. [Vitamin and mineral supplements in the diet of military personnel: effect on the balance of iron, copper and manganese, immune reactivity and physical work-capacity].

    Science.gov (United States)

    Zaĭtseva, I P; Nosolodin, V V; Zaĭtsev, O N; Gladkikh, I P; Koznienko, I V; Beliakov, R A; Arshinov, N P

    2012-03-01

    Conducted with the participation of 50 students of military educational study the effect of various vitamin and mineral complexes for the provision by the body naturally iron, copper and manganese on the immune and physical status. Found that diets enriched BMV was accompanied by a significant delay in the micro-elements, mainly iron, which indicates a deficiency of these bioelements in chickens Santo during the summer. Under the influence of vitamin-mineral complexes significantly increased rates of natural and specific immunity. As the delay increases significantly increased iron medical indicators of immunological reaction efficiency and physical performance.

  13. Avian magnetoreception: elaborate iron mineral containing dendrites in the upper beak seem to be a common feature of birds.

    Directory of Open Access Journals (Sweden)

    Gerald Falkenberg

    Full Text Available The magnetic field sensors enabling birds to extract orientational information from the Earth's magnetic field have remained enigmatic. Our previously published results from homing pigeons have made us suggest that the iron containing sensory dendrites in the inner dermal lining of the upper beak are a candidate structure for such an avian magnetometer system. Here we show that similar structures occur in two species of migratory birds (garden warbler, Sylvia borin and European robin, Erithacus rubecula and a non-migratory bird, the domestic chicken (Gallus gallus. In all these bird species, histological data have revealed dendrites of similar shape and size, all containing iron minerals within distinct subcellular compartments of nervous terminals of the median branch of the Nervus ophthalmicus. We also used microscopic X-ray absorption spectroscopy analyses to identify the involved iron minerals to be almost completely Fe III-oxides. Magnetite (Fe II/III may also occur in these structures, but not as a major Fe constituent. Our data suggest that this complex dendritic system in the beak is a common feature of birds, and that it may form an essential sensory basis for the evolution of at least certain types of magnetic field guided behavior.

  14. Avian magnetoreception: elaborate iron mineral containing dendrites in the upper beak seem to be a common feature of birds.

    Science.gov (United States)

    Falkenberg, Gerald; Fleissner, Gerta; Schuchardt, Kirsten; Kuehbacher, Markus; Thalau, Peter; Mouritsen, Henrik; Heyers, Dominik; Wellenreuther, Gerd; Fleissner, Guenther

    2010-02-16

    The magnetic field sensors enabling birds to extract orientational information from the Earth's magnetic field have remained enigmatic. Our previously published results from homing pigeons have made us suggest that the iron containing sensory dendrites in the inner dermal lining of the upper beak are a candidate structure for such an avian magnetometer system. Here we show that similar structures occur in two species of migratory birds (garden warbler, Sylvia borin and European robin, Erithacus rubecula) and a non-migratory bird, the domestic chicken (Gallus gallus). In all these bird species, histological data have revealed dendrites of similar shape and size, all containing iron minerals within distinct subcellular compartments of nervous terminals of the median branch of the Nervus ophthalmicus. We also used microscopic X-ray absorption spectroscopy analyses to identify the involved iron minerals to be almost completely Fe III-oxides. Magnetite (Fe II/III) may also occur in these structures, but not as a major Fe constituent. Our data suggest that this complex dendritic system in the beak is a common feature of birds, and that it may form an essential sensory basis for the evolution of at least certain types of magnetic field guided behavior.

  15. Substitution of manganese and iron into hydroxyapatite: Core/shell nanoparticles

    International Nuclear Information System (INIS)

    Pon-On, Weeraphat; Meejoo, Siwaporn; Tang, I.-Ming

    2008-01-01

    The bioceramics, hydroxyapatite (HAP), is a material which is biocompatible to the human body and is well suited to be used in hyperthermia applications for the treatment of bone cancer. We investigate the substitution of iron and manganese into the hydroxyapatite to yield ceramics having the empirical formula Ca 9.4 Fe 0.4 Mn 0.2 (PO 4 ) 6 (OH) 2 . The samples were prepared by the co-precipitation method. The formation of the nanocrystallites in the HAP structure as the heating temperatures were raised to obtain a glass-ceramic system are confirmed by X-ray diffraction, scanning electron microscopy (SEM), transmission electron microscopy (TEM), electron diffraction (ED) and electron spin resonance (ESR). TEM images show the core/shell structure of the nanoparticles, with the core being formed by the ferrites and the shell by the hydroxyapatite. The ED patterns indicate the nanoparticles formed at 500 deg. C have an amorphous structure while the nanoparticles formed at 1000 deg. C are crystalline. ESR spectroscopy indicated that the Fe 3+ ions have a g-factor of 4.23 and the Mn 2+ ions have a g-factor of 2.01. The values of the parameters in the spin Hamiltonian which describes the interaction between the transition metal ions and the Ca 2+ ions, indicate that the Mn 2+ ion substitute into the Ca 2+ sites which are ninefold coordinated, i.e., the Ca(1) sites

  16. Methodology for determination of trace elements in mineral phases of iron banded formation by LA-ICP-MS

    International Nuclear Information System (INIS)

    Sousa, Denise V.M. de; Nalini Junior, Herminio A.; Sampaio, Geraldo M.S.; Abreu, Adriana T. de; Lana, Cristiano de C.

    2015-01-01

    The study of the chemical composition of mineral phases of iron formation (FF), especially of trace elements, is an important tool in the understanding of the genesis of these rocks and the contribution of the phases in the composition of whole rock. Low mass fraction of such elements in the mineral phases present in this rock type requires a suitable analytical procedure. The laser ablation technique coupled with ICP-MS (LA-ICP-MS) has been widely used for determination of trace elements in geological samples. Thus, the aim of this study is to develop calibration curves for determination of trace elements (Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu) in mineral phases of banded iron formations by LA-ICP-MS. Several certified reference materials (CRM) were used for calibrate the equipment. The analytical conditions were checked by CRM NIST SRM 614. The results were satisfactory, since the curves showed good linearity coefficients, good accuracy and precision of results. (author)

  17. Shape preferred orientation of iron grains compatible with Earth's uppermost inner core hemisphericity

    Science.gov (United States)

    Calvet, Marie; Margerin, Ludovic

    2018-01-01

    Constraining the possible patterns of iron fabrics in the Earth's Uppermost Inner Core (UIC) is key to unravel the mechanisms controlling its growth and dynamics. In the framework of crystalline micro-structures composed of ellipsoidal, aligned grains, we discuss possible textural models of UIC compatible with observations of P-wave attenuation and velocity dispersion. Using recent results from multiple scattering theory in textured heterogeneous materials, we compute the P-wave phase velocity and scattering attenuation as a function of grain volume, shape, and orientation wrt to the propagation direction of seismic P-waves. Assuming no variations of the grain volume between the Eastern and Western hemisphere, we show that two families of texture are compatible with the degree-one structure of the inner core as revealed by the positive correlation between seismic velocity and attenuation. (1) Strong flattening of grains parallel to the Inner Core Boundary in the Western hemisphere and weak anisometry in the Eastern hemisphere. (2) Strong radial elongation of grains in the Western hemisphere and again weak anisometry in the Eastern hemisphere. Both textures can quantitatively explain the seismic data in a limited range of grain volumes. Furthermore, the velocity and attenuation anisotropy locally observed under Africa demands that the grains be locally elongated in the direction of Earth's meridians. Our study demonstrates that the hemispherical seismic structure of UIC can be entirely explained by changes in the shape and orientation of grains, thereby offering an alternative to changes in grain volumes. In the future, our theoretical toolbox could be used to systematically test the compatibility of textures predicted by geodynamical models with seismic observations.

  18. Large enhanced dielectric permittivity in polyaniline passivated core-shell nano magnetic iron oxide by plasma polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Joy, Lija K.; Sooraj, V.; Sethulakshmi, N.; Anantharaman, M. R., E-mail: mraiyer@yahoo.com [Department of Physics, Cochin University of Science and Technology, Cochin-682022, Kerala (India); Sajeev, U. S. [Department of Physics, Government College, Kottayam-686613, Kerala (India); Nair, Swapna S. [Department of Physics, School of Mathematical and Physical Sciences, Central University of Kerala, Kasargode-671123, Kerala (India); Narayanan, T. N. [CSIR-Central Electrochemical Research Institute, Karaikkudi-630006, Tamil Nadu (India); Ajayan, P. M. [Department of Material Science and Nano Engineering, Rice University, 6100 Main Street, Houston, Texas 7700 (United States)

    2014-03-24

    Commercial samples of Magnetite with size ranging from 25–30 nm were coated with polyaniline by using radio frequency plasma polymerization to achieve a core shell structure of magnetic nanoparticle (core)–Polyaniline (shell). High resolution transmission electron microscopy images confirm the core shell architecture of polyaniline coated iron oxide. The dielectric properties of the material were studied before and after plasma treatment. The polymer coated magnetite particles exhibited a large dielectric permittivity with respect to uncoated samples. The dielectric behavior was modeled using a Maxwell–Wagner capacitor model. A plausible mechanism for the enhancement of dielectric permittivity is proposed.

  19. Iron Oxide Minerals in Atmospheric Dust and Source Sediments-Studies of Types and Properties to Assess Environmental Effects

    Science.gov (United States)

    Reynolds, R. L.; Goldstein, H. L.; Moskowitz, B. M.; Till, J. L.; Flagg, C.; Kokaly, R. F.; Munson, S.; Landry, C.; Lawrence, C. R.; Hiza, M. M.; D'Odorico, P.; Painter, T. H.

    2011-12-01

    Ferric oxide minerals in atmospheric dust can influence atmospheric temperatures, accelerate melting of snow and ice, stimulate marine phytoplankton productivity, and impact human health. Such effects vary depending on iron mineral type, size, surface area, and solubility. Generally, the presence of ferric oxides in dust is seen in the red, orange, or yellow hues of plumes that originate in North Africa, central and southwest Asia, South America, western North America, and Australia. Despite their global importance, these minerals in source sediments, atmospheric dust, and downwind aeolian deposits remain poorly described with respect to specific mineralogy, particle size and surface area, or presence in far-traveled aerosol compounds. The types and properties of iron minerals in atmospheric dust can be better understood using techniques of rock magnetism (measurements at 5-300 K), Mössbauer and high-resolution visible and near-infrared reflectance spectroscopy; chemical reactivity of iron oxide phases; and electron microscopy for observing directly the ferric oxide coatings and particles. These studies can elucidate the diverse environmental effects of iron oxides in dust and can help to identify dust-source areas. Dust-source sediments from the North American Great Basin and Colorado Plateau deserts and the Kalahari Desert, southern Africa, were used to compare average reflectance values with a magnetic parameter (hard isothermal remanent magnetization, HIRM) for ferric oxide abundance. Lower reflectance values correspond strongly with higher HIRM values, indicating that ferric oxides (hematite or goethite, or both) contribute to absorption of solar radiation in these sediments. Dust deposited to snow cover of the San Juan Mountains (Colorado) and Wasatch Mountains (Utah) was used to characterize dust composition compared with properties of sediments exposed in source-areas identified from satellite retrievals. Results from multiple methods indicate that

  20. Economic value of Valentines iron minerals; Valor economico de los minerales de hierro de Valentines

    Energy Technology Data Exchange (ETDEWEB)

    Alvarado, B.

    1960-07-01

    This work is a investigation required by the government of Uruguay about the economic value of iron and manganese deposits in Valentines ferriferrous zone. The purpose is to study the potential commercial for the exportation.

  1. Iron released from ilmenite mineral sustains a phytoplankton community in microcosms

    Digital Repository Service at National Institute of Oceanography (India)

    Fernandes, C.E.G.; Velip, D.; Mourya, B.S.; Shaikh, S.; Das, A.; LokaBharathi, P.A.

    Natural biotic communities from Kalbadevi Bay were monitored in microcosms (1-l glass flasks) to test the hypothesis that iron released from ilmenite through microbial action contributes to proliferation of phytoplankton. Microcosms containing...

  2. Microwave absorption properties of the core/shell-type iron and nickel nanoparticles

    International Nuclear Information System (INIS)

    Lu, B.; Dong, X.L.; Huang, H.; Zhang, X.F.; Zhu, X.G.; Lei, J.P.; Sun, J.P.

    2008-01-01

    Iron (Fe) and nickel (Ni) nanoparticles were prepared by the DC arc-discharge method in a mixture of hydrogen and argon gases, using bulk metals as the raw materials. The microstructure of core/shell (metal/metal oxide) in nanoparticle formed after in situ passivation process. The complex electromagnetic parameters (permittivity ε r =ε r ' +iε r '' and permeability μ r =μ r ' +iμ r '' ) of the paraffin-mixed nanocomposite samples (paraffin:nanoparticles=1:1 in mass ratio) were measured in the frequency range of 2-18 GHz. The polarization mechanisms of the space charge and dipole coexist in both the Fe and Ni nanoparticles. The orientational polarization is a particular polarization for Fe nanoparticles and brings a relatively higher dielectric loss. Natural resonance is the main reason for magnetic loss and the corresponding frequencies are 11.6 and 5.2 GHz for the Fe and Ni nanoparticles, respectively. The paraffin composite with Fe nanoparticles provided excellent microwave absorption properties (reflection loss <-20 dB) in the range 6.8-16.6 GHz over the absorber thickness of 1.1-2.3 mm

  3. Microwave absorption properties of the core/shell-type iron and nickel nanoparticles

    Science.gov (United States)

    Lu, B.; Dong, X. L.; Huang, H.; Zhang, X. F.; Zhu, X. G.; Lei, J. P.; Sun, J. P.

    Iron (Fe) and nickel (Ni) nanoparticles were prepared by the DC arc-discharge method in a mixture of hydrogen and argon gases, using bulk metals as the raw materials. The microstructure of core/shell (metal/metal oxide) in nanoparticle formed after in situ passivation process. The complex electromagnetic parameters (permittivity ɛ=ɛr'+iɛr″ and permeability μ=μr'+iμr″) of the paraffin-mixed nanocomposite samples (paraffin:nanoparticles=1:1 in mass ratio) were measured in the frequency range of 2-18 GHz. The polarization mechanisms of the space charge and dipole coexist in both the Fe and Ni nanoparticles. The orientational polarization is a particular polarization for Fe nanoparticles and brings a relatively higher dielectric loss. Natural resonance is the main reason for magnetic loss and the corresponding frequencies are 11.6 and 5.2 GHz for the Fe and Ni nanoparticles, respectively. The paraffin composite with Fe nanoparticles provided excellent microwave absorption properties (reflection loss <-20 dB) in the range 6.8-16.6 GHz over the absorber thickness of 1.1-2.3 mm.

  4. Heavy sediment influx during early Holocene: Inference from clay mineral studies in a core from the western Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Reddy, N.P.C.; Rao, K.M.

    is attributed to heavy sediment influx du r- ing Mid Termination (MT) (12,500 ? 10,000 years BP), due to i n creased precipitation and run - off resulting from high inte n sity monsoonal regime. C LAY minerals are a powerful source for the interpret a... to address to the prov e nance of the sediments in a sediment core from the western Bengal Fan. In this paper, we report clay mi n eralogy and provide an explanation for the heavy sed i ment deposition du r ing the Holocene. A sediment core of 650...

  5. An Iron-Rain Model for Core Formation on Asteroid 4 Vesta

    Science.gov (United States)

    Kiefer, Walter S.; Mittlefehldt, David W.

    2016-01-01

    Asteroid 4 Vesta is differentiated into a crust, mantle, and core, as demonstrated by studies of the eucrite and diogenite meteorites and by data from NASA's Dawn spacecraft. Most models for the differentiation and thermal evolution of Vesta assume that the metal phase completely melts within 20 degrees of the eutectic temperature, well before the onset of silicate melting. In such a model, core formation initially happens by Darcy flow, but this is an inefficient process for liquid metal and solid silicate. However, the likely chemical composition of Vesta, similar to H chondrites with perhaps some CM or CV chondrite, has 13-16 weight percent S. For such compositions, metal-sulfide melting will not be complete until a temperature of at least 1350 degrees Centigrade. The silicate solidus for Vesta's composition is between 1100 and 1150 degrees Centigrade, and thus metal and silicate melting must have substantially overlapped in time on Vesta. In this chemically and physically more likely view of Vesta's evolution, metal sulfide drops will sink by Stokes flow through the partially molten silicate magma ocean in a process that can be envisioned as "iron rain". Measurements of eucrites show that moderately siderophile elements such as Ni, Mo, and W reached chemical equilibrium between the metal and silicate phases, which is an important test for any Vesta differentiation model. The equilibration time is a function of the initial metal grain size, which we take to be 25-45 microns based on recent measurements of H6 chondrites. For these sizes and reasonable silicate magma viscosities, equilibration occurs after a fall distance of just a few meters through the magma ocean. Although metal drops may grow in size by merger with other drops, which increases their settling velocities and decreases the total core formation time, the short equilibration distance ensures that the moderately siderophile elements will reach chemical equilibrium between metal and silicate before

  6. A code for the correction of field imperfections in iron-core superconducting magnets by shimming of iron

    International Nuclear Information System (INIS)

    Pradhan, J.; Bhunia, U.; Dey, M.K.; Mallik, C.; Bhandari, R.K.

    2005-01-01

    The magnetic field measurement of the median plane of K500 superconducting cyclotron at VECC have been carried out. A code has been developed using the mathematical software to calculate the magnetic field distribution for an arbitrary shaped saturated iron piece, and the various harmonics therein

  7. Repetitive on-demand drug release from polymeric matrices containing a macroscopic spherical iron core.

    Science.gov (United States)

    Rovers, Stefan A; Kemmere, Maartje F; Keurentjes, Jos T F; Hoogenboom, Richard

    2017-09-15

    A system for multiple on-demand drug release has been prepared that can be activated with an alternating magnetic field as external trigger. The core/shell samples have been developed based on a macroscopic spherical iron core coated with a thermoresponsive polymer, poly(styrene-stat-butyl methacrylate), containing ibuprofen as a model drug. During exposure of the samples to the magnetic field (ON state), the release rate of ibuprofen is significantly increased, up to 35 times the release rate without the magnetic field (OFF state). Using one sample or two samples in line with the magnetic field does not influence the ON/OFF ratio of the system, showing the possibility of using multiple samples to increase and tune the drug dose. Increasing the concentration of ibuprofen in the polymer layer is shown to increase the release rate in both the ON and OFF states. Increasing the size of the iron core and, consequently, decreasing the polymer thickness, was found to only increase the release rate during exposure resulting in higher ON/OFF ratios. The developed on demand drug delivery systems represents a promising development towards on demand drug delivery implants. During my chemical engineering studies, it was only during my master thesis work that I decided to continue with PhD research as I really enjoyed doing original research. When coming to the end of my PhD research under supervision of Prof. Ulrich S. Schubert, I developed the ambition to pursue an academic career. Fortunately, I got the opportunity to stay with Prof. Schubert as project leader for the Dutch Polymer Institute (DPI). Within this position, I supervised ten researchers and was able to start developing my independent research lines. Despite that I now advise students to not stay in the same laboratory, this first position allowed me to gain some initial independence and to publish a large number of papers that has been a great benefit in my further career. After two and a half years I needed a new

  8. Clay-mineral assemblages from some levels of K-118 drill core of Maha Sarakham evaporites, northeastern Thailand

    Science.gov (United States)

    Suwanich, Parkorn

    Clay-mineral assemblages in Middle Clastic, Middle Salt, Lower Clastic, Potash Zone, and Lower Salt, totalling 13 samples from K-118 drill core, in the Maha Sarakham Formation, Khorat Basin, northeastern Thailand were studied. The clay-size particles were separated from the water-soluble salt by water leaching. Then the samples were leached again in the EDTA solution and separated into clay-size particles by using the timing sedimentation. The EDTA-clay residues were divided and analyzed by using the XRD and XRF method. The XRD peaks show that the major-clay minerals are chlorite, illite, and mixed-layer corrensite including traces of rectorite? and paragonite? The other clay-size particles are quartz and potassium feldspar. The XRF results indicate Mg-rich values and moderate MgAl atom ratio values in those clay minerals. The variable Fe, Na, and K contents in the clay-mineral assemblages can explain the environment of deposition compared to the positions of the samples from the core. Hypothetically, mineralogy and the chemistry of the residual assemblages strongly indicate that severe alteration and Mg-enrichment of normal clay detritus occurred in the evaporite environment through brine-sediment interaction. The various Mg-enrichment varies along the various members reflecting whether sedimentation is near or far from the hypersaline brine.

  9. Iron speciation and mineral characterization of upper Jurassic reservoir rocks in the Minhe Basin, NW China

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Xiangxian; Zheng, Guodong, E-mail: gdzhbj@mail.iggcas.ac.cn; Xu, Wang [Chinese Academy of Sciences, Key Laboratory of Petroleum Resources, Gansu Province / Key Laboratory of Petroleum Resources Research, Institute of Geology and Geophysics (China); Liang, Minliang [Chinese Academy of Geological Sciences, Institute of Geomechanics, Key Lab of Shale Oil and Gas Geological Survey (China); Fan, Qiaohui; Wu, Yingzhong; Ye, Conglin [Chinese Academy of Sciences, Key Laboratory of Petroleum Resources, Gansu Province / Key Laboratory of Petroleum Resources Research, Institute of Geology and Geophysics (China); Shozugawa, Katsumi; Matsuo, Motoyuki [The University of Tokyo, Graduate School of Arts and Sciences (Japan)

    2016-12-15

    Six samples from a natural outcrop of reservoir rocks with oil seepage and two control samples from surrounding area in the Minhe Basin, northwestern China were selectively collected and analyzed for mineralogical composition as well as iron speciation using X-ray powder diffraction (XRD) and Mössbauer spectroscopy, respectively. Iron species revealed that: (1) the oil-bearing reservoir rocks were changed by water-rock-oil interactions; (2) even in the same site, there was a different performance between sandstone and mudstone during the oil and gas infusion to the reservoirs; and (3) this was evidence indicating the selective channels of hydrocarbon migration. In addition, these studies showed that the iron speciation by Mössbauer spectroscopy could be useful for the study of oil and gas reservoirs, especially the processes of the water-rock interactions within petroleum reservoirs.

  10. On the possibilities of age estimation of iron ore minerals using the Moessbauer effect

    International Nuclear Information System (INIS)

    Mbesherubusa, F.

    1980-01-01

    The age of geological iron are samples from regions with mainly oxidative conditions has been estimated, by the method of Moessbauer spectroscopy. In many cases the relative age of two samples could be determined unambigiously, due to the different Moessbauer data for Fe 2 + and Fe 3 + and the superparamagnetic behaviour of the iron oxide microcrystallites (up to about 200 A). This has been proved by three series of measurements with samples from three different climatic zones - Baja California, West-Australia, and Rhine Valley. (orig./HBR) [de

  11. Synthesis and morphology of iron-iron oxide core-shell nanoparticles produced by high pressure gas condensation

    NARCIS (Netherlands)

    Xing, Lijuan; ten Brink, Gert H.; Chen, Bin; Schmidt, Franz P.; Haberfehlner, Georg; Hofer, Ferdinand; Kooi, Bart J.; Palasantzas, Georgios

    2016-01-01

    Core-shell structured Fe nanoparticles (NPs) produced by high pressure magnetron sputtering gas condensation were studied using transmission electron microscopy (TEM) techniques, electron diffraction, electron energy-loss spectroscopy (EELS), tomographic reconstruction, and Wulff shape construction

  12. Remote-sensing data processing with the multivariate regression analysis method for iron mineral resource potential mapping: a case study in the Sarvian area, central Iran

    Science.gov (United States)

    Mansouri, Edris; Feizi, Faranak; Jafari Rad, Alireza; Arian, Mehran

    2018-03-01

    This paper uses multivariate regression to create a mathematical model for iron skarn exploration in the Sarvian area, central Iran, using multivariate regression for mineral prospectivity mapping (MPM). The main target of this paper is to apply multivariate regression analysis (as an MPM method) to map iron outcrops in the northeastern part of the study area in order to discover new iron deposits in other parts of the study area. Two types of multivariate regression models using two linear equations were employed to discover new mineral deposits. This method is one of the reliable methods for processing satellite images. ASTER satellite images (14 bands) were used as unique independent variables (UIVs), and iron outcrops were mapped as dependent variables for MPM. According to the results of the probability value (p value), coefficient of determination value (R2) and adjusted determination coefficient (Radj2), the second regression model (which consistent of multiple UIVs) fitted better than other models. The accuracy of the model was confirmed by iron outcrops map and geological observation. Based on field observation, iron mineralization occurs at the contact of limestone and intrusive rocks (skarn type).

  13. Iron

    DEFF Research Database (Denmark)

    Hansen, Jakob Bondo; Moen, I W; Mandrup-Poulsen, T

    2014-01-01

    and discuss recent evidence, suggesting that iron is a key pathogenic factor in both type 1 and type 2 diabetes with a focus on inflammatory pathways. Pro-inflammatory cytokine-induced β-cell death is not fully understood, but may include iron-induced ROS formation resulting in dedifferentiation by activation...... of transcription factors, activation of the mitochondrial apoptotic machinery or of other cell death mechanisms. The pro-inflammatory cytokine IL-1β facilitates divalent metal transporter 1 (DMT1)-induced β-cell iron uptake and consequently ROS formation and apoptosis, and we propose that this mechanism provides...

  14. Iron

    Science.gov (United States)

    ... Share: Search the ODS website Submit Search NIH Office of Dietary Supplements Consumer Datos en español Health ... eating a variety of foods, including the following: Lean meat, seafood, and poultry. Iron-fortified breakfast cereals ...

  15. Investigation of In-situ Biogeochemical Reduction of Chlorinated Solvents in Groundwater by Reduced Iron Minerals

    Science.gov (United States)

    Biogeochemical transformation is a process in which chlorinated solvents are degraded abiotically by reactive minerals formed by, at least in part or indirectly from, anaerobic biological processes. Five mulch biowall and/or vegetable oil-based bioremediation applications for tr...

  16. Superconducting superferric dipole magnet with cold iron core for the VLHC

    CERN Document Server

    Foster, G W

    2002-01-01

    Magnetic system of the stage I Very Large Hadron Collider (VLHC) is based on 2 Tesla superconducting magnets with combined functions. These magnets have a room temperature iron yoke with two 20 mm air gaps. Magnetic field in both horizontally separated air gaps is generated by a single, 100 kA superconducting transmission line. An alternative design with a cold iron yoke, horizontally or vertically separated air gaps is under investigation. The cold iron option with horizontally separated air gaps reduces the amount of iron, which is one of the major cost drivers for the 233-km magnet system of future accelerator. The vertical beam separation decreases the superconductor volume, heat load from the synchrotron radiation and eliminates fringe field from the return bus. Nevertheless, the horizontal beam separation provides lowest volume of the iron yoke and, therefore, smaller heat load on the cryogenic system during cooling down. All these options are discussed and compared in the paper. Superconducting correct...

  17. Thermodynamic data for modeling acid mine drainage problems: compilation and estimation of data for selected soluble iron-sulfate minerals

    Science.gov (United States)

    Hemingway, Bruch S.; Seal, Robert R.; Chou, I-Ming

    2002-01-01

    Enthalpy of formation, Gibbs energy of formation, and entropy values have been compiled from the literature for the hydrated ferrous sulfate minerals melanterite, rozenite, and szomolnokite, and a variety of other hydrated sulfate compounds. On the basis of this compilation, it appears that there is no evidence for an excess enthalpy of mixing for sulfate-H2O systems, except for the first H2O molecule of crystallization. The enthalpy and Gibbs energy of formation of each H2O molecule of crystallization, except the first, in the iron(II) sulfate - H2O system is -295.15 and -238.0 kJ?mol-1, respectively. The absence of an excess enthalpy of mixing is used as the basis for estimating thermodynamic values for a variety of ferrous, ferric, and mixed-valence sulfate salts of relevance to acid-mine drainage systems.

  18. Decline in the lung cancer hazard: a prospective study of the mortality of iron ore miners in Cumbria

    International Nuclear Information System (INIS)

    Kinlen, L.J.

    1988-01-01

    The mortality of 1947 Cumbrian iron ore miners has been studied over the period 1939-82 in relation to that among other groups of men in England and Wales: (a) all men, (b) men of similar social class, and (c) men living in similar types of (mainly rural) area. Significant excesses were found for deaths from tuberculosis and respiratory diseases compared with each of the reference populations. Lung cancer showed an excess over that in comparable (mainly rural) areas of England and Wales, as reported in a previous study using a proportionate method of analysis and which covered the period 1948-67 but no appreciable excess after 1967. Reasons for this decline are discussed. (author)

  19. Iron and manganese in oxide minerals and in glasses: preliminary consideration of Eh buffering potential at Yucca Mountain, Nevada

    International Nuclear Information System (INIS)

    Caporuscio, F.A.; Vaniman, D.T.

    1985-04-01

    The tuffs of Yucca Mountain at the Nevada Test Site are currently under investigation as a possible deep burial site for high-level radioactive waste disposal. One of the main concerns is the effect of oxidizing groundwater on the transport of radionuclides. Rock components that may affect the oxygen content of groundwater include Fe-Ti oxides, Mn oxides, and glasses that contain ferrous iron. Some phenocryst Fe-Ti oxides at Yucca Mountain are in reduced states, whereas groundmass Fe-Ti oxides have been oxidized to hematite, rutile, and pseudobrookite (Fe 3+ -bearing phases) exclusively. Estimates of Fe 2+ -bearing oxides indicate that less than 0.33 vol% phenocrysts is available to act as solid buffering agents of Eh. Of this percentage, significant amounts of Fe-Ti oxides are isolated from effective interaction with groundwater because they occur in densely welded, devitrified tuffs that have low interstitial permeability. Manganese oxides occur primarily along fractures in the ash-flow tuffs. Because the Mn oxides are concentrated along the same pathways (fractures) where transport has occurred in the past, these small volume percentages could act as buffers. However, the oxidation states of actual Mn-oxide phases are high (Mn 4+ ), and these minerals have virtually no potential for reducing groundwater Eh. Manganese oxides may even act as oxidizing agents. However, regardless of their poor capabilities as reducing agents, the Mn oxides could be important as sorbents of heavy metals at Yucca Mountain. The lack of accessible, pristine Fe-Ti oxides and the generally high oxidation states of Mn oxides seem to rule out these oxides as Eh buffers of the Yucca Mountain groundwater system. Reduction of ferrous iron within glassy tuffs may have some effect on Eh, but further study is needed. At present it is prudent to assume that minerals and glasses have little or no capacity for reducing oxygen-rich groundwater at Yucca Mountain. 25 refs., 3 figs., 12 tabs

  20. Synthesis of composite nanoparticles using co-precipitation of a magnetic iron-oxide shell onto core nanoparticles

    International Nuclear Information System (INIS)

    Primc, Darinka; Belec, Blaž; Makovec, Darko

    2016-01-01

    Composite nanoparticles can be synthesized by coating a shell made of one material onto core nanoparticles made of another material. Here we report on a novel method for coating a magnetic iron oxide onto the surface of core nanoparticles in an aqueous suspension. The method is based on the heterogeneous nucleation of an initial product of Fe"3"+/Fe"2"+ co-precipitation on the core nanoparticles. The close control of the supersaturation of the precipitating species required for an exclusively heterogeneous nucleation and the growth of the shell were achieved by immobilizing the reactive Fe"3"+ ions in a nitrate complex with urea ([Fe((CO(NH_2)_2)_6](NO_3)_3) and by using solid Mg(OH)_2 as the precipitating reagent. The slow thermal decomposition of the complex at 60 °C homogeneously releases the reactive Fe"3"+ ions into the suspension of the core nanoparticles. The key stage of the process is the thermal hydrolysis of the released Fe"3"+ ions prior to the addition of Mg(OH)_2. The thermal hydrolysis results in the formation of γ-FeOOH, exclusively at the surfaces of the core nanoparticles. After the addition of the solid hydroxide Mg(OH)_2, the pH increases and at pH ~ 5.7 the Fe"2"+ precipitates and reacts with the γ-FeOOH to form magnetic iron oxide with a spinel structure (spinel ferrite) at the surfaces of the core nanoparticles. The proposed low-temperature method for the synthesis of composite nanoparticles is capable of forming well-defined interfaces between the two components, important for the coupling of the different properties. The procedure is environmentally friendly, inexpensive, and appropriate for scaling up to mass production.Graphical abstract

  1. Antimony Adsorption from Zarshouran Gold Mineral Processing Plant Wastewater by Nano Zero Valent Iron Coated on Bentonite

    Directory of Open Access Journals (Sweden)

    nader nosrati

    2015-03-01

    Full Text Available The effluent from Zarshouran gold mineral processing plant contains high quantities of arsenic, antimony, mercury, and bismuth. These metals and metalloids are soluble in water and very toxic when they enter the environment. Their solubility in water causes the polluted area to extend beyond their point of origin. In this article, different methods of antimony removal from water and wastewater were reviewed and the zero-valent iron nanoparticles coated on Bentonite were selected as an effective and low cost material for removing antimony from wastewater. For the purposes of this study, zero-valent iron nanoparticles of 40-100 nanometers in size were synthesized by dropwise addition of sodium borohydride solution to an Iron (III aqueous solution at  ambient temperature and mixed with nitrogen gas. To avoid particle agglomeration and to enhance the product’s environmentally safe application, the  nanoparticles were coated on Bentonite and characterized by SEM/EDAX and BET. The experiments were carried out by intense mixing of the adsorbent with 10ml of real/synthtic wastewater samples in 20ml bottles.  The effects of pH, contact time, temperature, and adsorbent dosage on antimony removal efficiency were investigated under intense mixing using a magnetic mixer. Finally, the effluents were filtered upon completion of the experiments and used for atomic adsorption analysis. The results of the experiments showed that the adsorption isotherms of the synthesized nanoparticles obeyed the Langmuir and Freundlich models. The experiments carried out on real samples showed that antimony adsorption capacity for B-nZVI was 2.6 mg/g of the adsorbent and that the highest antimony removal efficiency was 99.56%.

  2. Study of iron deposit using seismic refraction and resistivity in Carajás Mineral Province, Brazil

    Science.gov (United States)

    Nogueira, Pedro Vencovsky; Rocha, Marcelo Peres; Borges, Welitom Rodrigues; Silva, Adalene Moreira; Assis, Luciano Mozer de

    2016-10-01

    This work comprises the acquisition, processing and interpretation of 2D seismic shallow refraction (P-wave) and resistivity profiles located in the iron ore deposit of N4WS, Carajás Mineral Province (CMP), northern Brazil. The geophysical methods were used to identify the boundaries of the iron ore deposit. Another objective was to evaluate the potentiality of these geophysical methods in that geological context. In order to validate the results, the geophysical lines were located to match a geological borehole line. For the seismic refraction, we used 120 channels, spaced by 10 m, in a line of 1190 m, with seven shot points. The resistivity method used in the acquisition was the electrical resistivity imaging, with pole-pole array, in order to reach greater depths. The resistivity line had a length of 1430 m, with 10 m spacing between electrodes. The seismic results produced a model with two distinct layers. Based on the velocities values, the first layer was interpreted as altered rocks, and the second layer as more preserved rocks. It was not possible to discriminate different lithologies with the seismic method inside each layer. From the resistivity results, a zone of higher resistivity (> 3937 Ω·m) was interpreted as iron ore, and a region of intermediate resistivity (from 816 to 2330 Ω·m) as altered rocks. These two regions represent the first seismic layer. On the second seismic layer, an area with intermediated resistivity values (from 483 to 2330 Ω·m) was interpreted as mafic rocks, and the area with lower resistivity (boreholes and show reasonable correlation, suggesting that the geophysical anomalies correspond to the main variations in composition and physical properties of rocks.

  3. Very low sound velocities in iron-rich (Mg,Fe)O: Implications for the core-mantle boundary region

    International Nuclear Information System (INIS)

    Wicks, J.K.; Jackson, J.M.; Sturhahn, W.

    2010-01-01

    The sound velocities of (Mg .16 Fe .84 )O have been measured to 121 GPa at ambient temperature using nuclear resonant inelastic x-ray scattering. The effect of electronic environment of the iron sites on the sound velocities were tracked in situ using synchrotron Moessbauer spectroscopy. We found the sound velocities of (Mg .16 Fe .84 )O to be much lower than those in other presumed mantle phases at similar conditions, most notably at very high pressures. Conservative estimates of the effect of temperature and dilution on aggregate sound velocities show that only a small amount of iron-rich (Mg,Fe)O can greatly reduce the average sound velocity of an assemblage. We propose that iron-rich (Mg,Fe)O be a source of ultra-low velocity zones. Other properties of this phase, such as enhanced density and dynamic stability, strongly support the presence of iron-rich (Mg,Fe)O in localized patches above the core-mantle boundary.

  4. Dose-effect relationship between the thorium lung burden and the hepatic function of the miners at the Bayan Obo Rare-earth Iron Mine

    International Nuclear Information System (INIS)

    Cheng, Yong-e; Chen, Xing-an

    2008-01-01

    The purpose of this paper is to present the dose effect relationship between the thorium lung burden and the hepatic function of the miners at the Bayun Obo Rare-earth Iron Mine. The methods we used is to carry out the measurement of each miner.s exhaled thoron activity and the thorium lung burden along with the four hepatic functions (thymol turbidity test, glutamic pyruvic transaminase, thymol flocculation test and alkaline phosphatase)of the dust exposed miners in Bayun Obo Rare-earth Iron Mine. We have carried out three investigations in 1983, 1984-1987 and 1994 respectively. Results showed that during the period 1983-1994, 1158 measurements of thorium lung burden estimates and 1158 measurement of every four hepatic functions(altogether 4632 measurements) were performed on 638 dust-exposed miners. No adverse effects were observed. In the same time, none of the above-mentioned 638 exposed miners had a thorium lung burden higher than 11.11 Bq. It is concluded that if any miners. thorium lung burden not higher than 11.11 Bq, his four hepatic functions should not be affected. This first possible threshold for thorium lung burden affecting the hepatic functions was put forward by the authors and confirmed by the Information Center of Chinese Academy of Medical Science in 2003 after searching 23.6 million references. (author)

  5. Minerals in fractures of the saturated zone from drill core USW G-4, Yucca Mountain, Nye County, Nevada

    International Nuclear Information System (INIS)

    Carlos, B.A.

    1987-04-01

    The minerals in fractures in drill core USW G-4, from the static water level (SWL) at 1770 ft to the base of the hole at 3000 ft, were studied to determine their identity and depositional sequence and to compare them with those found above the SWL in the same drill hole. There is no change in mineralogy or mineral morphology across the SWL. The significant change in mineralogy and relationship to the host rock occurs at 1381 ft, well above the present water table. Below 1381 ft clinoptilolite appears in the fractures and rock matrix instead of heulandite, and the fracture mineralogy correlates with the host rock mineralogy. Throughout most of the saturated zone (below the SWL) in USW G-4, zeolites occur in fractures only in zeolitic tuff; however, zeolites persist in fracture below the base of the deepest zeolitic tuff interval. Nonzeolitic intervals of tuff have fewer fractures, and many of these have no coatings; a few have quartz and feldspar coatings. One interval in zeolitic tuff (2125-2140 ft) contains abundant crisobalite coatings in the fractures. Calcite occurs in fractures from 2575 to 2660 ft, usually with the manganese mineral hollandite, and from 2750 to 2765 ft, usually alone. Manganese minerals occur in several intervals. The spatial correlation of zeolites in fractures with zeolitic host rock suggests that both may have been zeolitized at the same time, possibly by water moving laterally through more permeable zones in the tuff. The continuation of zeolites in fractures below the lowest zeolitic interval in this hole suggests that vertical fracture flow may have been important in the deposition of these coatings. Core from deeper intervals in another hole will be examined to determine if that relationship continues. 17 refs., 19 figs

  6. Abiotic versus biotic iron mineral transformation studied by a miniaturized backscattering Mössbauer spectrometer (MIMOS II), X-ray diffraction and Raman spectroscopy

    Science.gov (United States)

    Markovski, C.; Byrne, J. M.; Lalla, E.; Lozano-Gorrín, A. D.; Klingelhöfer, G.; Rull, F.; Kappler, A.; Hoffmann, T.; Schröder, C.

    2017-11-01

    Searching for biomarkers or signatures of microbial transformations of minerals is a critical aspect for determining how life evolved on Earth, and whether or not life may have existed in other planets, including Mars. In order to solve such questions, several missions to Mars have sought to determine the geochemistry and mineralogy on the Martian surface. This research includes the two miniaturized Mössbauer spectrometers (MIMOS II) on board the Mars Exploration Rovers Spirit and Opportunity, which have detected a variety of iron minerals on Mars, including magnetite (Fe2+Fe3+2O4) and goethite (α-FeO(OH)). On Earth, both minerals can derive from microbiological activity (e.g. through dissimilatory iron reduction of ferrihydrite by Fe(III)-reducing bacteria). Here we used a lab based MIMOS II to characterize the mineral products of biogenic transformations of ferrihydrite to magnetite by the Fe(III)-reducing bacteria Geobacter sulfurreducens. In combination with Raman spectroscopy and X-ray diffraction (XRD), we observed the formation of magnetite, goethite and siderite. We compared the material produced by biogenic transformations to abiotic samples in order to distinguish abiotic and biotic iron minerals by techniques that are or will be available onboard Martian based laboratories. The results showed the possibility to distinguish the abiotic and biotic origin of the minerals. Mossbauer was able to distinguish the biotic/abiotic magnetite with the interpretation of the geological context (Fe content mineral assemblages and accompanying minerals) and the estimation of the particle size in a non-destructive way. The Raman was able to confirm the biotic/abiotic principal peaks of the magnetite, as well as the organic principal vibration bands attributed to the bacteria. Finally, the XRD confirmed the particle size and mineralogy.

  7. Study of the rhizobacterium Azospirillum brasilense Sp245 using Mössbauer spectroscopy with a high velocity resolution: Implication for the analysis of ferritin-like iron cores

    Science.gov (United States)

    Alenkina, I. V.; Oshtrakh, M. I.; Tugarova, A. V.; Biró, B.; Semionkin, V. A.; Kamnev, A. A.

    2014-09-01

    The results of a comparative study of two samples of the rhizobacterium Azospirillum brasilense (strain Sp245) prepared in different conditions and of human liver ferritin using Mössbauer spectroscopy with a high velocity resolution demonstrated the presence of ferritin-like iron (i.e. iron similar to that found in ferritin-like proteins) in the bacterium. Mössbauer spectra of these samples were fitted in two ways: as a rough approximation using a one quadrupole doublet fit (the homogeneous iron core model) and using a superposition of quadrupole doublets (the heterogeneous iron core model). Both results demonstrated differences in the Mössbauer parameters for mammalian ferritin and for bacterial ferritin-like iron. Moreover, some differences in the Mössbauer parameters were observed between the two samples of A. brasilense Sp245 related to the differences in their preparation conditions.

  8. Iron-mineral accretion from acid mine drainage and its application in passive treatment

    Science.gov (United States)

    Florence, K.; Sapsford, D.J.; Johnson, D.B.; Kay, C.M.; Wolkersdorfer, C.

    2016-01-01

    ABSTRACT This study demonstrates substantial removal of iron (Fe) from acid mine drainage (pH ≈3) in a passive vertical flow reactor (VFR) with an equivalent footprint of 154 m2 per L/s mine water and residence times of >23 h. Average Fe removal rate was 67% with a high of 85% over the 10-month trial. The fraction of Fe passing a 0.22 µm filter (referred to here as Fe-filt) was seen to be removed in the VFR even when Fe(II) was absent, indicating that the contribution of microbial Fe(II) oxidation and precipitation was not the dominant removal mechanism in the VFR. Removal rates of Fe-filt in the VFR were up to 70% in residence times as low as 8 h compared with laboratory experiments where much smaller changes in Fe-filt were observed over 60 h. Centrifugation indicated that 80–90% of the influent Fe had particle sizes mine water revealed the abundance of extracellular polymeric substance-generating Fe-oxidizing bacterium ‘Ferrovum myxofaciens’, which may aid the removal of iron and explain the unusual appearance and physical properties of the sludge. PMID:26675674

  9. Iron-mineral accretion from acid mine drainage and its application in passive treatment.

    Science.gov (United States)

    Florence, K; Sapsford, D J; Johnson, D B; Kay, C M; Wolkersdorfer, C

    2016-01-01

    This study demonstrates substantial removal of iron (Fe) from acid mine drainage (pH ≈3) in a passive vertical flow reactor (VFR) with an equivalent footprint of 154 m(2) per L/s mine water and residence times of >23 h. Average Fe removal rate was 67% with a high of 85% over the 10-month trial. The fraction of Fe passing a 0.22 µm filter (referred to here as Fe-filt) was seen to be removed in the VFR even when Fe(II) was absent, indicating that the contribution of microbial Fe(II) oxidation and precipitation was not the dominant removal mechanism in the VFR. Removal rates of Fe-filt in the VFR were up to 70% in residence times as low as 8 h compared with laboratory experiments where much smaller changes in Fe-filt were observed over 60 h. Centrifugation indicated that 80-90% of the influent Fe had particle sizes water was contacted with VFR sludge, the Fe-filt fraction was destabilized, leading to an appreciably higher removal of this fraction. Heterogeneous precipitation and/or aggregation of nanoparticulate Fe(III) precipitates are considered predominant removal mechanisms. Microbial analyses of the mine water revealed the abundance of extracellular polymeric substance-generating Fe-oxidizing bacterium 'Ferrovum myxofaciens', which may aid the removal of iron and explain the unusual appearance and physical properties of the sludge.

  10. Multistage Core Formation in Planetesimals Revealed by Numerical Modeling and Hf-W Chronometry of Iron Meteorites

    Science.gov (United States)

    Neumann, W.; Kruijer, T. S.; Breuer, D.; Kleine, T.

    2018-02-01

    Iron meteorites provide some of the most direct insights into the processes and timescales of core formation in planetesimals. Of these, group IVB irons stand out by having one of the youngest 182Hf-182W model ages for metal segregation (2.9 ± 0.6 Ma after solar system formation), as well as the lowest bulk sulfur content and hence highest liquidus temperature. Here, using a new model for the internal evolution of the IVB parent body, we show that a single stage of metal-silicate separation cannot account for the complete melting of pure Fe metal at the relatively late time given by the Hf-W model age. Instead, a complex metal-silicate separation scenario is required that includes migration of partial silicate melts, formation of a shallow magma ocean, and core formation in two distinct stages of metal segregation. In the first stage, a protocore formed at ≈1.5 Ma via settling of metal particles in a mantle magma ocean, followed by metal segregation from a shallow magma ocean at ≈5.4 Ma. As these stages of metal segregation occurred at different times, the two metal fractions had different 182W compositions. Consequently, the final 182W composition of the IVB core does not correspond to a single differentiation event, but represents the average composition of early- and late-segregated core fractions. Our best fit model indicates an ≈100 km radius for the IVB parent body and provides an accretion age of ≈0.1-0.5 Ma after solar system formation. The computed solidification time is, furthermore, consistent with the Re-Os age for crystallization of the IVB core.

  11. Bench top and portable mineral analysers, borehole core analysers and in situ borehole logging

    International Nuclear Information System (INIS)

    Howarth, W.J.; Watt, J.S.

    1982-01-01

    Bench top and portable mineral analysers are usually based on balanced filter techniques using scintillation detectors or on low resolution proportional detectors. The application of radioisotope x-ray techniques to in situ borehole logging is increasing, and is particularly suited for logging for tin and higher atomic number elements

  12. Biological mineralization of iron: Studies using Moesbauer spectroscopy and complementary techniques

    International Nuclear Information System (INIS)

    Webb, J.; Kim, K.S.; Tran, K.C.; Pierre, T.G.S.

    1988-01-01

    Biological deposition of solid Fe-containing phases can be studied using 57 Fe Moessbauer spectroscopy. Other techniques are needed in order to understand this complex process. These include proton-induced X-ray and γ-ray emission (PIXE/PIGME), electron microscopy, electron and X-ray diffraction, infrared spectroscopy and chemical characterization of organic components. This paper reviews and evaluates the application of these techniques to biological mineralization of Fe, particularly that occurring in the radula teeth of the marine molluscs, chitons and limpets. (orig.)

  13. Uranium isotope ratios of Muonionalusta troilite and complications for the absolute age of the IVA iron meteorite core

    Science.gov (United States)

    Brennecka, Gregory A.; Amelin, Yuri; Kleine, Thorsten

    2018-05-01

    The crystallization ages of planetary crustal material (given by basaltic meteorites) and planetary cores (given by iron meteorites) provide fiducial marks for the progress of planetary formation, and thus, the absolute ages of these objects fundamentally direct our knowledge and understanding of planet formation and evolution. The lone precise absolute age of planetary core material was previously obtained on troilite inclusions from the IVA iron meteorite Muonionalusta. This previously reported Pb-Pb age of 4565.3 ± 0.1 Ma-assuming a 238U/235U =137.88-only post-dated the start of the Solar System by approximately 2-3 million years, and mandated fast cooling of planetary core material. Since an accurate Pb-Pb age requires a known 238U/235U of the sample, we have measured both 238U/235U and Pb isotopic compositions of troilite inclusions from Muonionalusta. The measured 238U/235U of the samples range from ∼137.84 to as low as ∼137.22, however based on Pb and U systematics, terrestrial contamination appears pervasive and has affected samples to various extents for Pb and U. The cause of the relative 235U excess in one sample does not appear to be from terrestrial contamination or the decay of short-lived 247Cm, but is more likely from fractionation of U isotopes during metal-silicate separation during core formation, exacerbated by the extreme U depletion in the planetary core. Due to limited Pb isotopic variation and terrestrial disturbance, no samples of this study produced useful age information; however the clear divergence from the previously assumed 238U/235U of any troilite in Muonionalusta introduces substantial uncertainty to the previously reported absolute age of the sample without knowledge of the 238U/235U of the sample. Uncertainties associated with U isotope heterogeneity do not allow for definition of a robust age of solidification and cooling for the IVA core. However, one sample of this work-paired with previous work using short

  14. The design, fabrication and testing of an iron-core current compensated magnetic channel for cyclotron extraction

    International Nuclear Information System (INIS)

    Laxdale, R.E.; Fong, K.; Houtman, H.

    1994-06-01

    An iron-core current compensated magnetic channel has been built ss part of the TRIUMF 450 MeV H - extraction feasibility project. The channel would operate in the 0.5 T cyclotron field and was designed using the two-dimensional code POISSON. Recent beam tests with the channel installed in the TRIUMF cyclotron confirmed that the electro-mechanical design is reliable and that the effect on the circulating beam is in agreement with calculation. The design and hardware details will be described and the beam test results reported. (author)

  15. Pyrophosphate synthesis in iron mineral films and membranes simulating prebiotic submarine hydrothermal precipitates

    Science.gov (United States)

    Barge, Laura M.; Doloboff, Ivria J.; Russell, Michael J.; VanderVelde, David; White, Lauren M.; Stucky, Galen D.; Baum, Marc M.; Zeytounian, John; Kidd, Richard; Kanik, Isik

    2014-03-01

    Cells use three main ways of generating energy currency to drive metabolism: (i) conversion of adenosine diphosphate (ADP) to adenosine triphosphate (ATP) by the proton motive force through the rotor-stator ATP synthase; (ii) the synthesis of inorganic phosphate˜phosphate bonds via proton (or sodium) pyrophosphate synthase; or (iii) substrate-level phosphorylation through the direct donation from an active phosphoryl donor. A mechanism to produce a pyrophosphate bond as “energy currency” in prebiotic systems is one of the most important considerations for origin of life research. Baltscheffsky (1996) suggests that inorganic pyrophosphate (PO74-; PPi) may have preceded ATP/ADP as an energy storage molecule in earliest life, produced by an H+ pyrophosphatase. Here we test the hypothesis that PPi could be synthesized in inorganic precipitates simulating hydrothermal chimney structures transected by thermal and/or ionic gradients. Appreciable yields of PPi were obtained via substrate phosphorylation by acetyl phosphate within the iron sulfide/silicate precipitates at temperatures expected for an alkaline hydrothermal system. The formation of PPi only occurred in the solid phase, i.e. when both Pi and the phosphoryl donor were precipitated with Fe-sulfides or Fe-silicates. The amount of Ac-Pi incorporated into the precipitate was a significant factor in the amount of PPi that could form, and phosphate species were more effectively incorporated into the precipitate at higher temperatures (⩾50 to >85 °C). Thus, we expect that the hydrothermal precipitate would be more enriched in phosphate (and especially, Ac-Pi) near the inner margins of a hydrothermal mound where PPi formation would be at a maximum. Iron sulfide and iron silicate precipitates effectively stabilized Ac-Pi and PPi against hydrolysis (relative to hydrolysis in aqueous solution). Thus it is plausible that PPi could accumulate as an energy currency up to useful concentrations for early life in a

  16. Trend overtime of total haemoglobin, iron metabolism and trace minerals in veal calves fed high amounts of two different solid feeds

    Directory of Open Access Journals (Sweden)

    Anna-Lisa Stefani

    2010-01-01

    Full Text Available Fifty Polish Friesian veal calves were administrated high amounts of two different solid feeds (maize grain and a mix diet containing 10% of straw and 8% of soy in addition to the traditional milk replacer diet. Compared to the mix diet, maize grain had a lower content of iron, copper and zinc and a minor fibre level. Effects of the two diets on calves’ blood haemoglobin, iron, iron metabolism parameters, copper and zinc concentrations were studied. Haemoglobin concentration resulted higher at the end of the fattening for calves fed the mix diet, as expected. Values remained, however, within ranges that allowed acceptable carcass paleness. Haematic iron, unsaturated iron binding capacity (UIBC and total iron binding capacity (TIBC levels were not significantly different between the two solid feeds. Lower copper and zinc blood concentrations resulted for calves fed the mix diet were likely due to the feed fibre interfering with the bioavailability of the two minerals, according to what happens for iron.

  17. Bacillus subtilis biofilm development in the presence of soil clay minerals and iron oxides.

    Science.gov (United States)

    Ma, Wenting; Peng, Donghai; Walker, Sharon L; Cao, Bin; Gao, Chun-Hui; Huang, Qiaoyun; Cai, Peng

    2017-01-01

    Clay minerals and metal oxides, as important parts of the soil matrix, play crucial roles in the development of microbial communities. However, the mechanism underlying such a process, particularly on the formation of soil biofilm, remains poorly understood. Here, we investigated the effects of montmorillonite, kaolinite, and goethite on the biofilm formation of the representative soil bacteria Bacillus subtilis . The bacterial biofilm formation in goethite was found to be impaired in the initial 24 h but burst at 48 h in the liquid-air interface. Confocal laser scanning microscopy showed that the biofilm biomass in goethite was 3-16 times that of the control, montmorillonite, and kaolinite at 48 h. Live/Dead staining showed that cells had the highest death rate of 60% after 4 h of contact with goethite, followed by kaolinite and montmorillonite. Atomic force microscopy showed that the interaction between goethite and bacteria may injure bacterial cells by puncturing cell wall, leading to the swarming of bacteria toward the liquid-air interface. Additionally, the expressions of abrB and sinR , key players in regulating the biofilm formation, were upregulated at 24 h and downregulated at 48 h in goethite, indicating the initial adaptation of the cells to minerals. A model was proposed to describe the effects of goethite on the biofilm formation. Our findings may facilitate a better understanding of the roles of soil clays in biofilm development and the manipulation of bacterial compositions through controlling the biofilm in soils.

  18. Microstructures, mineral chemistry, noble gases and nitrogen in the recent fall, Bhuka iron (IAB) meteorite

    Science.gov (United States)

    Murty, S. V. S.; Ranjith, P. M.; Ray, Dwijesh; Ghosh, S.; Chattopadhyay, Basab; Shrivastava, K. L.

    2016-10-01

    We report some chemical, petrological and isotopic studies of the Bhuka iron meteorite that fell in Rajasthan, India in 2005. Numerous silicate and graphite inclusions are visible on the surface of the hand specimen. In the polished and etched surface studied, irregular patches of graphite are found as the most dominant inclusion and commonly associated with pure corundum (95 wt% Al2O3), spinel, feldspar and Si-rich phases. Apart from typical lamellar intergrowth with kamacite (i.e. the Widmänstatten pattern), taenites are also commonly found to occur as a rim of the graphite inclusions. P-rich (up to 10 wt%) taenites are also found locally within the recrystallised kamacite matrix. Based on mineralogy, texture and bulk composition, Bhuka resembles the low-Ni IAB subgroup (ungrouped). Noble gas isotope studies suggest He, Ne and Ar are mostly of cosmogenic origin, while Kr and Xe are a mixture of cosmogenic, radiogenic and trapped components. A pre-atmospheric radius of 10±1 cm and a cosmic ray exposure age of 346±52 Ma are derived based on depth dependant (3He/4He)c and 38Arc respectively, as per the production systematics of cosmogenic noble gas isotopes (Ammon et al., 2009). Cosmogenic 83Kr and 126Xe yield production rates of 12 and 0.335 (in 10-15ccSTP/g Ma) for 83Kr and 126Xe respectively. Presence of trapped Kr and Xe, with (84Kr/132Xe)t=2 and radiogenic 129Xe=120×10-12 ccSTP/g are due to presence of graphite/silicate inclusions in the analysed sample. Over 150% excess 131Xec than expected from spallation suggests contribution from (n,ɤ) reactions from Ba from inclusions and suggests irradiation of pre-atmospheric object in a larger body, indicative of complex irradiation. Trapped N of 24 ppm, with δ15N=-10.7±0.8‰ observed in Bhuka, is heavier than the range observed hither to in IAB irons.

  19. Evaluation of constitutive iron reductase (AtFRO2) expression on mineral accumulation and distribution in soybean (Glycine max L.)

    Science.gov (United States)

    Iron is an important micronutrient in human and plant nutrition. Adequate iron nutrition during crop production is central for assuring appropriate iron concentrations in the harvestable organs, for human food or animal feed. The whole-plant movement of iron involves several processes, including the...

  20. The Supplementation Effects of Iron and Folic Acid Compared with the Multivitamin and Mineral on Female Workers of Childbearing Age in the Pineapple Agribusiness

    Directory of Open Access Journals (Sweden)

    Yaktiworo Indriani

    2013-06-01

    Full Text Available Female workers of childbearing age (WUS as a major of human resources in many agribusiness exposed to anemia. This study aims to improve the iron status of anemic WUS workers with low hemoglobin (Hb levels, who work in a pineapple agribusiness by iron supplementation. This study was conducted two periods, using a double-blind randomized trial design. Subjects were divided into two treatment groups supplements, namely IF that was given iron + folic acid and MVM that was given multi vitamin and mineral containing 15 different vitamins and minerals including iron and folic acid. The subjects of period-1 were 25 married WUS (IF=13, MVM=12 and of period-2 were 15 single WUS (BF=7, MVM=8. Supplementation performed three times weekly for 10 weeks. After supplementation, the levels of Hb, haematocrit (Hc and serum ferritin of BF-group increased, whereas there were declines in MVM-group. The increase in Hb and Hc in married WUS was higher than the single. However, their Hb was fallen down when supplementation was continued without supervision and getting down when not given the supplements anymore. Supplementation with iron is a must for WUS workers, because they are not able to increase their Hb if only rely on their food.

  1. Temperature and mineral dust variability recorded in two low-accumulation Alpine ice cores over the last millennium

    Science.gov (United States)

    Bohleber, Pascal; Erhardt, Tobias; Spaulding, Nicole; Hoffmann, Helene; Fischer, Hubertus; Mayewski, Paul

    2018-01-01

    Among ice core drilling sites in the European Alps, Colle Gnifetti (CG) is the only non-temperate glacier to offer climate records dating back at least 1000 years. This unique long-term archive is the result of an exceptionally low net accumulation driven by wind erosion and rapid annual layer thinning. However, the full exploitation of the CG time series has been hampered by considerable dating uncertainties and the seasonal summer bias in snow preservation. Using a new core drilled in 2013 we extend annual layer counting, for the first time at CG, over the last 1000 years and add additional constraints to the resulting age scale from radiocarbon dating. Based on this improved age scale, and using a multi-core approach with a neighbouring ice core, we explore the time series of stable water isotopes and the mineral dust proxies Ca2+ and insoluble particles. Also in our latest ice core we face the already known limitation to the quantitative use of the stable isotope variability based on a high and potentially non-stationary isotope/temperature sensitivity at CG. Decadal trends in Ca2+ reveal substantial agreement with instrumental temperature and are explored here as a potential site-specific supplement to the isotope-based temperature reconstruction. The observed coupling between temperature and Ca2+ trends likely results from snow preservation effects and the advection of dust-rich air masses coinciding with warm temperatures. We find that if calibrated against instrumental data, the Ca2+-based temperature reconstruction is in robust agreement with the latest proxy-based summer temperature reconstruction, including a Little Ice Age cold period as well as a medieval climate anomaly. Part of the medieval climate period around AD 1100-1200 clearly stands out through an increased occurrence of dust events, potentially resulting from a relative increase in meridional flow and/or dry conditions over the Mediterranean.

  2. Temperature and mineral dust variability recorded in two low-accumulation Alpine ice cores over the last millennium

    Directory of Open Access Journals (Sweden)

    P. Bohleber

    2018-01-01

    Full Text Available Among ice core drilling sites in the European Alps, Colle Gnifetti (CG is the only non-temperate glacier to offer climate records dating back at least 1000 years. This unique long-term archive is the result of an exceptionally low net accumulation driven by wind erosion and rapid annual layer thinning. However, the full exploitation of the CG time series has been hampered by considerable dating uncertainties and the seasonal summer bias in snow preservation. Using a new core drilled in 2013 we extend annual layer counting, for the first time at CG, over the last 1000 years and add additional constraints to the resulting age scale from radiocarbon dating. Based on this improved age scale, and using a multi-core approach with a neighbouring ice core, we explore the time series of stable water isotopes and the mineral dust proxies Ca2+ and insoluble particles. Also in our latest ice core we face the already known limitation to the quantitative use of the stable isotope variability based on a high and potentially non-stationary isotope/temperature sensitivity at CG. Decadal trends in Ca2+ reveal substantial agreement with instrumental temperature and are explored here as a potential site-specific supplement to the isotope-based temperature reconstruction. The observed coupling between temperature and Ca2+ trends likely results from snow preservation effects and the advection of dust-rich air masses coinciding with warm temperatures. We find that if calibrated against instrumental data, the Ca2+-based temperature reconstruction is in robust agreement with the latest proxy-based summer temperature reconstruction, including a Little Ice Age cold period as well as a medieval climate anomaly. Part of the medieval climate period around AD 1100–1200 clearly stands out through an increased occurrence of dust events, potentially resulting from a relative increase in meridional flow and/or dry conditions over the Mediterranean.

  3. Electron-capture and Low-mass Iron-core-collapse Supernovae: New Neutrino-radiation-hydrodynamics Simulations

    Science.gov (United States)

    Radice, David; Burrows, Adam; Vartanyan, David; Skinner, M. Aaron; Dolence, Joshua C.

    2017-11-01

    We present new 1D (spherical) and 2D (axisymmetric) simulations of electron-capture (EC) and low-mass iron-core-collapse supernovae (SN). We consider six progenitor models: the ECSN progenitor from Nomoto; two ECSN-like low-mass low-metallicity iron-core progenitors from A. Heger (2016, private communication); and the 9, 10, and 11 {M}⊙ (zero-age main-sequence) progenitors from Sukhbold et al. We confirm that the ECSN and ESCN-like progenitors explode easily even in 1D with explosion energies of up to a 0.15 Bethes (1 {{B}}\\equiv {10}51 {erg}), and are a viable mechanism for the production of very-low-mass neutron stars. However, the 9, 10, and 11 {M}⊙ progenitors do not explode in 1D and are not even necessarily easier to explode than higher-mass progenitor stars in 2D. We study the effect of perturbations and of changes to the microphysics and we find that relatively small changes can result in qualitatively different outcomes, even in 1D, for models sufficiently close to the explosion threshold. Finally, we revisit the impact of convection below the protoneutron star (PNS) surface. We analyze 1D and 2D evolutions of PNSs subject to the same boundary conditions. We find that the impact of PNS convection has been underestimated in previous studies and could result in an increase of the neutrino luminosity by up to factors of two.

  4. Current limiting behavior in three-phase transformer-type SFCLs using an iron core according to variety of fault

    Science.gov (United States)

    Cho, Yong-Sun; Jung, Byung-Ik; Ha, Kyoung-Hun; Choi, Soo-Geun; Park, Hyoung-Min; Choi, Hyo-Sang

    To apply the superconducting fault current limiter (SFCL) to the power system, the reliability of the fault-current-limiting operation must be ensured in diverse fault conditions. The SFCL must also be linked to the operation of the high-speed recloser in the power system. In this study, a three-phase transformer-type SFCL, which has a neutral line to improve the simultaneous quench characteristics of superconducting elements, was manufactured to analyze the fault-current-limiting characteristic according to the single, double, and triple line-to-ground faults. The transformer-type SFCL, wherein three-phase windings are connected to one iron core, reduced the burden on the superconducting element as the superconducting element on the sound phase was also quenched in the case of the single line-to-ground fault. In the case of double or triple line-to-ground faults, the flux from the faulted phase winding was interlinked with other faulted or sound phase windings, and the fault-current-limiting rate decreased because the windings of three phases were inductively connected by one iron core.

  5. Shape-Controlled Synthesis of Magnetic Iron Oxide@SiO₂-Au@C Particles with Core-Shell Nanostructures.

    Science.gov (United States)

    Li, Mo; Li, Xiangcun; Qi, Xinhong; Luo, Fan; He, Gaohong

    2015-05-12

    The preparation of nonspherical magnetic core-shell nanostructures with uniform sizes still remains a challenge. In this study, magnetic iron oxide@SiO2-Au@C particles with different shapes, such as pseduocube, ellipsoid, and peanut, were synthesized using hematite as templates and precursors of magnetic iron oxide. The as-obtained magnetic particles demonstrated uniform sizes, shapes, and well-designed core-shell nanostructures. Transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDX) analysis showed that the Au nanoparticles (AuNPs) of ∼6 nm were uniformly distributed between the silica and carbon layers. The embedding of the metal nanocrystals into the two different layers prevented the aggregation and reduced the loss of the metal nanocrystals during recycling. Catalytic performance of the peanut-like particles kept almost unchanged without a noticeable decrease in the reduction of 4-nitrophenol (4-NP) in 8 min even after 7 cycles, indicating excellent reusability of the particles. Moreover, the catalyst could be readily recycled magnetically after each reduction by an external magnetic field.

  6. Fe2+ oxidation rate drastically affect the formation and phase of secondary iron hydroxysulfate mineral occurred in acid mine drainage

    International Nuclear Information System (INIS)

    Huang Shan; Zhou Lixiang

    2012-01-01

    During the processes of secondary iron hydroxysulfate mineral formation, Fe 2+ ion was oxidized by the following three methods: (1) biooxidation treatment by Acidithiobacillus ferrooxidans (A. ferrooxidans); (2) rapid abiotic oxidation of Fe 2+ with H 2 O 2 (rapid oxidation treatment); (3) slow abiotic oxidation of Fe 2+ with H 2 O 2 (slow oxidation treatment). X-ray diffraction (XRD) patterns, element composition, precipitate weight and total Fe removal efficiency were analyzed. The XRD patterns and element composition of precipitates synthesized through the biooxidation and the slow oxidation treatments well coincide with those of potassium jarosite, while precipitates formed at the initial stage of incubation in the rapid oxidation treatment showed a similar XRD pattern to schwertmannite. With the ongoing incubation, XRD patterns and element composition of the precipitates that occurred in the rapid oxidation treatment were gradually close to those in the biooxidation and the slow oxidation treatments. Due to the inhibition of A. ferrooxidans itself and its extracellular polymeric substances (EPS) in aggregation of precipitates, the amount of precipitates and soluble Fe removal efficiency were lower in the biooxidation treatment than in the slow oxidation treatment. Therefore, it is concluded that Fe 2+ oxidation rate can greatly affect the mineral phase of precipitates, and slow oxidation of Fe 2+ is helpful in improving jarosite formation. - Highlights: ► Slow oxidation of Fe 2+ is helpful in jarosite formation. ► The already-formed schwertmannite can be gradually transformed to jarosite. ► Precipitates formation can be inhibited probably by EPS from A. ferrooxidans.

  7. Characterization of Coated Sand Cores from Two Different Binder Systems for Grey Iron Castings

    DEFF Research Database (Denmark)

    Nwaogu, Ugochukwu Chibuzoh; Tiedje, Niels Skat; Poulsen, Thomas

    or veining and metal penetration defects. The use of refractory coatings on cores is fundamental to obtaining acceptable casting surface quality and is used on resin bonded cores in production foundries. In this study new sol gel-coated sand cores made from coldbox and furan binder systems were investigated......Expansion defects on the surface of the castings include sand burn-in, metal penetration and/or veining, finning or scab. Veining or finning and metal penetration are of interest. These defects are associated with silica sand and result from the penetration of liquid metal into cracks formed during...... differential expansion of the core during heating. The rapid expansion of silica sand up to 600 oC and especially at 573 oC, where the α – β phase transformation occurs, is the cause of stresses in the core system. These stresses cause crack formation and metal melt flows into these cracks causing finning...

  8. Direct observations of the viscosity of Earth's outer core and extrapolation of measurements of the viscosity of liquid iron

    International Nuclear Information System (INIS)

    Smylie, D E; Brazhkin, Vadim V; Palmer, Andrew

    2009-01-01

    Estimates vary widely as to the viscosity of Earth's outer fluid core. Directly observed viscosity is usually orders of magnitude higher than the values extrapolated from high-pressure high-temperature laboratory experiments, which are close to those for liquid iron at atmospheric pressure. It turned out that this discrepancy can be removed by extrapolating via the widely known Arrhenius activation model modified by lifting the commonly used assumption of pressure-independent activation volume (which is possible due to the discovery that at high pressures the activation volume increases strongly with pressure, resulting in 10 2 Pa s at the top of the fluid core, and in 10 11 Pa s at its bottom). There are of course many uncertainties affecting this extrapolation process. This paper reviews two viscosity determination methods, one for the top and the other for the bottom of the outer core, the former of which relies on the decay of free core nutations and yields 2371 ± 1530 Pa s, while the other relies on the reduction in the rotational splitting of the two equatorial translational modes of the solid inner core oscillations and yields an average of 1.247 ± 0.035 Pa s. Encouraged by the good performance of the Arrhenius extrapolation, a differential form of the Arrhenius activation model is used to interpolate along the melting temperature curve and to find the viscosity profile across the entire outer core. The viscosity variation is found to be nearly log-linear between the measured boundary values. (methodological notes)

  9. A/C magnetic hyperthermia of melanoma mediated by iron(0)/iron oxide core/shell magnetic nanoparticles: a mouse study

    International Nuclear Information System (INIS)

    Balivada, Sivasai; Koper, Olga B; Tamura, Masaaki; Chikan, Viktor; Bossmann, Stefan H; Troyer, Deryl L; Rachakatla, Raja Shekar; Wang, Hongwang; Samarakoon, Thilani N; Dani, Raj Kumar; Pyle, Marla; Kroh, Franklin O; Walker, Brandon; Leaym, Xiaoxuan

    2010-01-01

    There is renewed interest in magnetic hyperthermia as a treatment modality for cancer, especially when it is combined with other more traditional therapeutic approaches, such as the co-delivery of anticancer drugs or photodynamic therapy. The influence of bimagnetic nanoparticles (MNPs) combined with short external alternating magnetic field (AMF) exposure on the growth of subcutaneous mouse melanomas (B16-F10) was evaluated. Bimagnetic Fe/Fe 3 O 4 core/shell nanoparticles were designed for cancer targeting after intratumoral or intravenous administration. Their inorganic center was protected against rapid biocorrosion by organic dopamine-oligoethylene glycol ligands. TCPP (4-tetracarboxyphenyl porphyrin) units were attached to the dopamine-oligoethylene glycol ligands. The magnetic hyperthermia results obtained after intratumoral injection indicated that micromolar concentrations of iron given within the modified core-shell Fe/Fe 3 O 4 nanoparticles caused a significant anti-tumor effect on murine B16-F10 melanoma with three short 10-minute AMF exposures. We also observed a decrease in tumor size after intravenous administration of the MNPs followed by three consecutive days of AMF exposure 24 hrs after the MNPs injection. These results indicate that intratumoral administration of surface modified MNPs can attenuate mouse melanoma after AMF exposure. Moreover, we have found that after intravenous administration of micromolar concentrations, these MNPs are capable of causing an anti-tumor effect in a mouse melanoma model after only a short AMF exposure time. This is a clear improvement to state of the art

  10. Magnetotelluric evidence for a deep-crustal mineralizing system beneath the Olympic Dam iron oxide copper-gold deposit, southern Australia

    Science.gov (United States)

    Heinson, Graham S.; Direen, Nicholas G.; Gill, Rob M.

    2006-07-01

    The iron oxide copper-gold Olympic Dam deposit, situated along the margin of the Proterozoic Gawler craton, South Australia, is the world's largest uranium deposit and sixth-largest copper deposit; it also contains significant reserves of gold, silver, and rare earth elements. Gaining a better understanding of the mechanisms for genesis of the economic liberalization is fundamental for defining exploration models in similar crustal settings. To delineate crustal structures that may constrain mineral system fluid pathways, coincident deep crustal seismic and magnetotelluric (MT) transects were obtained along a 220 km section that crosses Olympic Dam and the major crustal boundaries. In this paper we present results from 58 long-period (10 104 s) MT sites, with site spacing of 5 10 km. A two-dimensional inversion of MT data from 33 sites to a depth of 100 km shows four notable features: (1) sedimentary cover sequences with low resistivity (1000 Ω·m) Archean crustal core from a more conductive crust and mantle to the north (typically Olympic Dam, the upper-middle crust to ˜20 km is quite resistive (˜1000 Ω·m), but the lower crust is much more conductive (Olympic Dam, we image a low-resistivity region (Olympic Dam may be due to the upward movement of CO2-bearing volatiles near the time of deposit formation that precipitated conductive graphite liberalization along grain boundaries, simultaneously annihilating acoustic impedance boundaries. The source of the volatiles may be from the mantle degassing or retrograde metamorphism of the lower crust associated with Proterozoic crustal deformation.

  11. Iron Oxide Nanoparticles: Tunable Size Synthesis and Analysis in Terms of the Core-Shell Structure and Mixed Coercive Model

    Science.gov (United States)

    Phong, P. T.; Oanh, V. T. K.; Lam, T. D.; Phuc, N. X.; Tung, L. D.; Thanh, Nguyen T. K.; Manh, D. H.

    2017-04-01

    Iron oxide nanoparticles (NPs) are currently a very active research field. To date, a comprehensive study of iron oxide NPs is still lacking not only on the size dependence of structural phases but also in the use of an appropriate model. Herein, we report on a systematic study of the structural and magnetic properties of iron oxide NPs prepared by a co-precipitation method followed by hydrothermal treatment. X-ray diffraction and transmission electron microscopy reveal that the NPs have an inverse spinel structure of iron oxide phase (Fe3O4) with average crystallite sizes ( D XRD) of 6-19 nm, while grain sizes ( D TEM) are of 7-23 nm. In addition, the larger the particle size, the closer the experimental lattice constant value is to that of the magnetite structure. Magnetic field-dependent magnetization data and analysis show that the effective anisotropy constants of the Fe3O4 NPs are about five times larger than that of their bulk counterpart. Particle size ( D) dependence of the magnetization and the non-saturating behavior observed in applied fields up to 50 kOe are discussed using the core-shell structure model. We find that with decreasing D, while the calculated thickness of the shell of disordered spins ( t ˜ 0.3 nm) remains almost unchanged, the specific surface areas S a increases significantly, thus reducing the magnetization of the NPs. We also probe the coercivity of the NPs by using the mixed coercive Kneller and Luborsky model. The calculated results indicate that the coercivity rises monotonously with the particle size, and are well matched with the experimental ones.

  12. Equation of state of iron under core conditions of large rocky exoplanets

    Science.gov (United States)

    Smith, Raymond F.; Fratanduono, Dayne E.; Braun, David G.; Duffy, Thomas S.; Wicks, June K.; Celliers, Peter M.; Ali, Suzanne J.; Fernandez-Pañella, Amalia; Kraus, Richard G.; Swift, Damian C.; Collins, Gilbert W.; Eggert, Jon H.

    2018-06-01

    The recent discovery of thousands of planets outside our Solar System raises fundamental questions about the variety of planetary types and their corresponding interior structures and dynamics. To better understand these objects, there is a strong need to constrain material properties at the extreme pressures found within planetary interiors1,2. Here we used high-powered lasers at the National Ignition Facility to ramp compress iron over nanosecond timescales to 1.4 TPa (14 million atmospheres)—a pressure four times higher than for previous static compression data. A Lagrangian sound-speed analysis was used to determine pressure, density and sound speed along a continuous isentropic compression path. Our peak pressures are comparable to those predicted at the centre of a terrestrial-type exoplanet of three to four Earth masses3, representing the first absolute equation of state measurements for iron at such conditions. These results provide an experiment-based mass-radius relationship for a hypothetical pure iron planet that can be used to evaluate plausible compositional space for large, rocky exoplanets.

  13. Proxies and measurement techinques for mineral dust in antarctic ice cores

    DEFF Research Database (Denmark)

    Ruth..[], Urs; Bigler, Matthias

    2008-01-01

    analysis), elemental analysis (inductively coupled plasma mass spectroscopy at pH 1 and after full acid digestion), and water-insoluble elemental analysis (proton induced X-ray emission). Antarctic ice core samples covering the last deglaciation from the EPICA Dome C (EDC) and the EPICA Dronning Maud Land......-MS measurements depends on the digestion method and is different for different elements and during different climatic periods. EDC and EDML samples have similar dust composition, which suggests a common dust source or a common mixture of sources for the two sites. The analyzed samples further reveal a change...

  14. Binding of heavy metal ions in aggregates of microbial cells, EPS and biogenic iron minerals measured in-situ using metal- and glycoconjugates-specific fluorophores

    Science.gov (United States)

    Hao, Likai; Guo, Yuan; Byrne, James M.; Zeitvogel, Fabian; Schmid, Gregor; Ingino, Pablo; Li, Jianli; Neu, Thomas R.; Swanner, Elizabeth D.; Kappler, Andreas; Obst, Martin

    2016-05-01

    Aggregates consisting of bacterial cells, extracellular polymeric substances (EPS) and Fe(III) minerals formed by Fe(II)-oxidizing bacteria are common at bulk or microscale chemical interfaces where Fe cycling occurs. The high sorption capacity and binding capacity of cells, EPS, and minerals controls the mobility and fate of heavy metals. However, it remains unclear to which of these component(s) the metals will bind in complex aggregates. To clarify this question, the present study focuses on 3D mapping of heavy metals sorbed to cells, glycoconjugates that comprise the majority of EPS constituents, and Fe(III) mineral aggregates formed by the phototrophic Fe(II)-oxidizing bacteria Rhodobacter ferrooxidans SW2 using confocal laser scanning microscopy (CLSM) in combination with metal- and glycoconjugates-specific fluorophores. The present study evaluated the influence of glycoconjugates, microbial cell surfaces, and (biogenic) Fe(III) minerals, and the availability of ferrous and ferric iron on heavy metal sorption. Analyses in this study provide detailed knowledge on the spatial distribution of metal ions in the aggregates at the sub-μm scale, which is essential to understand the underlying mechanisms of microbe-mineral-metal interactions. The heavy metals (Au3+, Cd2+, Cr3+, CrO42-, Cu2+, Hg2+, Ni2+, Pd2+, tributyltin (TBT) and Zn2+) were found mainly sorbed to cell surfaces, present within the glycoconjugates matrix, and bound to the mineral surfaces, but not incorporated into the biogenic Fe(III) minerals. Statistical analysis revealed that all ten heavy metals tested showed relatively similar sorption behavior that was affected by the presence of sorbed ferrous and ferric iron. Results in this study showed that in addition to the mineral surfaces, both bacterial cell surfaces and the glycoconjugates provided most of sorption sites for heavy metals. Simultaneously, ferrous and ferric iron ions competed with the heavy metals for sorption sites on the organic

  15. Synthesis and magnetic properties of cobalt-iron/cobalt-ferrite soft/hard magnetic core/shell nanowires

    Science.gov (United States)

    Leandro Londoño-Calderón, César; Moscoso-Londoño, Oscar; Muraca, Diego; Arzuza, Luis; Carvalho, Peterson; Pirota, Kleber Roberto; Knobel, Marcelo; Pampillo, Laura Gabriela; Martínez-García, Ricardo

    2017-06-01

    A straightforward method for the synthesis of CoFe2.7/CoFe2O4 core/shell nanowires is described. The proposed method starts with a conventional pulsed electrodeposition procedure on alumina nanoporous template. The obtained CoFe2.7 nanowires are released from the template and allowed to oxidize at room conditions over several weeks. The effects of partial oxidation on the structural and magnetic properties were studied by x-ray spectrometry, magnetometry, and scanning and transmission electron microscopy. The results indicate that the final nanowires are composed of 5 nm iron-cobalt alloy nanoparticles. Releasing the nanowires at room conditions promoted surface oxidation of the nanoparticles and created a CoFe2O4 shell spinel-like structure. The shell avoids internal oxidation and promotes the formation of bi-magnetic soft/hard magnetic core/shell nanowires. The magnetic properties of both the initial single-phase CoFe2.7 nanowires and the final core/shell nanowires, reveal that the changes in the properties from the array are due to the oxidation more than effects associated with released processes (disorder and agglomeration).

  16. Role of glutaredoxin 3 in iron homeostasis

    Science.gov (United States)

    Iron is an essential mineral nutrient that is tightly regulated through mechanisms involving iron regulatory genes, intracellular storage, and iron recycling. Dysregulation of these mechanisms often results in either excess tissue iron accumulation (overload) or iron deficiency (anemia). Many bioche...

  17. Influence of New Sol-gel Refractory Coating on the Casting Properties of Cold Box and Furan Cores for Grey Cast iron

    DEFF Research Database (Denmark)

    Nwaogu, Ugochukwu Chibuzoh; Poulsen, T.; Bischoff, C

    2010-01-01

    New Sol-Gel coated sand cores made from coldbox and furan binder systems were investigated. The idea of the coating was to improve the surface quality of castings. Grey iron was cast on the cores in a sand casting process. The effect of the high temperature of the melt on the cores was assessed...... by measuring the heating curves. The viscosity of the coating, moisture content and the permeability of the cores were evaluated. The surface quality of the castings was investigated using SEM and OM. The results show that the moisture content of the cores affected the permeability. In furan cores the vapour...... transport zone (VTZ) when in contact with the melt is larger than it is in a coldbox which means the furan cores have higher moisture content. The new sol-gel coating has the potential for improving the surface quality of castings without negative effects on the graphite distribution. The surface...

  18. Transformation of Reactive Iron Minerals in a Permeable Reactive Barrier (Biowall) Used to Treat TCE in Groundwater

    Science.gov (United States)

    Abstract: Iron and sulfur reducing conditions are generally created in permeable reactive barrier (PRB) systems constructed for groundwater treatment, which usually leads to formation of iron sulfide phases. Iron sulfides have been shown to play an important role in degrading ch...

  19. Determining the size of nanoparticles in the example of magnetic iron oxide core-shell systems

    Science.gov (United States)

    Jarzębski, Maciej; Kościński, Mikołaj; Białopiotrowicz, Tomasz

    2017-08-01

    The size of nanoparticles is one of the most important factors for their possible applications. Various techniques for the nanoparticle size characterization are available. In this paper selected techniques will be considered base on the prepared core-shell magnetite nanoparticles. Magnetite is one of the most investigated and developed magnetic material. It shows interesting magnetic properties which can be used for biomedical applications, such as drug delivery, hypothermia and also as a contrast agent. To reduce the toxic effects of Fe3O4, magnetic core was covered by dextran and gelatin. Moreover, the shell was doped by fluorescent dye for confocal microscopy investigation. The main investigation focused on the methods for particles size determination of modified magnetite nanoparticles prepared with different techniques. The size distribution were obtained by nanoparticle tracking analysis, dynamic light scattering and transmission electron microscopy. Furthermore, fluorescent correlation spectroscopy (FCS) and confocal microscopy were used to compare the results for particle size determination of core-shell systems.

  20. Rapid bacterial mineralization of organic carbon produced during a phytoplankton bloom induced by natural iron fertilization in the Southern Ocean

    Science.gov (United States)

    Obernosterer, Ingrid; Christaki, Urania; Lefèvre, Dominique; Catala, Philippe; Van Wambeke, France; Lebaron, Philippe

    2008-03-01

    The response of heterotrophic bacteria ( Bacteria and Archaea) to the spring phytoplankton bloom that occurs annually above the Kerguelen Plateau (Southern Ocean) due to natural iron fertilization was investigated during the KErguelen Ocean and Plateau compared Study (KEOPS) cruise in January-February 2005. In surface waters (upper 100 m) in the core of the phytoplankton bloom, heterotrophic bacteria were, on an average, 3-fold more abundant and revealed rates of production ([ 3H] leucine incorporation) and respiration (bacterial metabolic activities were attributable to high-nucleic-acid-containing cells that dominated (≈80% of total cell abundance) the heterotrophic bacterial community associated with the phytoplankton bloom. Bacterial growth efficiencies varied between 14% and 20% inside the bloom and were bacterial activity, due to the stimulation by phytoplankton-derived dissolved organic matter. Within the Kerguelen bloom, bacterial carbon demand accounted for roughly 45% of gross community production. These results indicate that heterotrophic bacteria processed a significant portion of primary production, with most of it being rapidly respired.

  1. Pore to core scale simulation of the mass transfer with mineral reaction in porous media

    International Nuclear Information System (INIS)

    Bekri, S.; Renard, S.; Delprat-Jannaud, F.

    2015-01-01

    Pore Network Model (PNM) is used to simulate mass transfer with mineral reaction in a single phase flow through porous medium which is here a sandstone sample from the reservoir formation of the Pakoslaw gas field. The void space of the porous medium is represented by an idealized geometry of pore-bodies joined by pore-throats. Parameters defining the pore-bodies and the pore-throats distribution are determined by an optimization process aiming to match the experimental Mercury Intrusion Capillary Pressure (MICP) curve and petrophysical properties of the rock such as intrinsic permeability and formation factor. The generated network is used first to simulate the multiphase flow by solving Kirchhoff's laws. The capillary pressure and relative permeability curves are derived. Then, reactive transport is addressed under asymptotic regime where the solute concentration undergoes an exponential evolution with time. The porosity/ permeability relationship and the three phenomenological coefficients of transport, namely the solute velocity, the dispersion and the mean reaction rate are determined as functions of Peclet and Peclet-Damkohler dimensionless numbers. Finally, the role of the dimensionless numbers on the reactive flow properties is highlighted. (authors)

  2. A/C magnetic hyperthermia of melanoma mediated by iron(0/iron oxide core/shell magnetic nanoparticles: a mouse study

    Directory of Open Access Journals (Sweden)

    Koper Olga B

    2010-03-01

    Full Text Available Abstract Background There is renewed interest in magnetic hyperthermia as a treatment modality for cancer, especially when it is combined with other more traditional therapeutic approaches, such as the co-delivery of anticancer drugs or photodynamic therapy. Methods The influence of bimagnetic nanoparticles (MNPs combined with short external alternating magnetic field (AMF exposure on the growth of subcutaneous mouse melanomas (B16-F10 was evaluated. Bimagnetic Fe/Fe3O4 core/shell nanoparticles were designed for cancer targeting after intratumoral or intravenous administration. Their inorganic center was protected against rapid biocorrosion by organic dopamine-oligoethylene glycol ligands. TCPP (4-tetracarboxyphenyl porphyrin units were attached to the dopamine-oligoethylene glycol ligands. Results The magnetic hyperthermia results obtained after intratumoral injection indicated that micromolar concentrations of iron given within the modified core-shell Fe/Fe3O4 nanoparticles caused a significant anti-tumor effect on murine B16-F10 melanoma with three short 10-minute AMF exposures. We also observed a decrease in tumor size after intravenous administration of the MNPs followed by three consecutive days of AMF exposure 24 hrs after the MNPs injection. Conclusions These results indicate that intratumoral administration of surface modified MNPs can attenuate mouse melanoma after AMF exposure. Moreover, we have found that after intravenous administration of micromolar concentrations, these MNPs are capable of causing an anti-tumor effect in a mouse melanoma model after only a short AMF exposure time. This is a clear improvement to state of the art.

  3. Distribution of iron, manganese, cobalt and nickel in sediment cores of the northeastern Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, Ch.M.; Setty, M.G.A.P.

    :72; 3:205; and 6:265; (b) for the slope it is 1:116; and (c) the basin 6:170. The values are highest in one core. This suggests an enrichment of manganese in the shelf region and in the basin, but great mobility in the slope and parts of the shelf...

  4. The biological properties of iron oxide core high-density lipoprotein in experimental atherosclerosis

    NARCIS (Netherlands)

    Skajaa, Torjus; Cormode, David P.; Jarzyna, Peter A.; Delshad, Amanda; Blachford, Courtney; Barazza, Alessandra; Fisher, Edward A.; Gordon, Ronald E.; Fayad, Zahi A.; Mulder, Willem J. M.

    2011-01-01

    Lipoproteins are a family of plasma nanoparticles responsible for the transportation of lipids throughout the body. High-density lipoprotein (HDL), the smallest of the lipoprotein family, measures 7-13 nm in diameter and consists of a cholesteryl ester and triglyceride core that is covered with a

  5. Influence of the dislocation core on the glide of the 1/2 < 111 >{110} edge dislocation in bcc-iron: An embedded atom method study

    Czech Academy of Sciences Publication Activity Database

    Haghighat, S.M.H.; von Pezold, J.; Race, C. P.; Kormann, F.; Friák, Martin; Neugebauer, J.; Raabe, D.

    2014-01-01

    Roč. 87, MAY (2014), s. 274-282 ISSN 0927-0256 Institutional support: RVO:68081723 Keywords : Molecular dynamics * Edge dislocation * Core structure * Dislocation glide * Iron Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.131, year: 2014

  6. Contribution in the study of the stability of Callovo-Oxfordian clay rock minerals in the presence of iron at 90 deg C

    International Nuclear Information System (INIS)

    Rivard, Camille

    2011-01-01

    In the context of underground disposal of high-level radioactive waste, it is of prime importance to understand the interaction mechanisms between Callovo-Oxfordian clay rock (COx), selected as a potential host-rock by Andra (French national radioactive waste management agency) and metallic iron, that enters the composition of containers and disposal cells. Interactions between metallic iron and COx clay-rock, COx Callovo-Oxfordian clay fraction (SCOx) and pure clay phases (kaolinite, illite, smectites) were investigated at 90 deg. C under anoxic atmosphere in chlorine solution. In order to study the role of COx non clay minerals, the reactivity of mixtures between SCOx and quartz, calcite, dolomite or pyrite, was also studied. Liquid and solid by-products were characterised by chemical analyses, mineralogical and morphometric techniques, at different scales. In our experimental conditions, major evolutions were observed during the first month, which shows that the oxidation of metallic iron is rapid. The release of iron cations in solution, pH increase (8-10) and Eh decrease (reductive conditions) are responsible for the partial dissolution of initial clay phases. Released iron is involved in the crystallization of Fe-serpentines (odinite or berthierite mainly) or precipitates under the form of magnetite in low amount. Fe-serpentine stability is controlled by the redox conditions as the introduction of dioxygen into the system leads to iron exsolution under the form of iron oxides and hydroxides and precipitation of clay particles with composition close to the initial ones. Whereas carbonates and pyrite do not significantly influence SCOx-metallic iron interactions, reaction pathways are modified in the presence of quartz. Indeed, in such conditions one observes a slight decrease of pH, an increase in Eh, the absence of magnetite and differences in the crystal chemistry of Fe-serpentines that are silica enriched, in comparison with those formed without any quartz

  7. Transport properties of iron at Earth’s core conditions: The effect of spin disorder

    Czech Academy of Sciences Publication Activity Database

    Drchal, Václav; Kudrnovský, Josef; Wagenknecht, D.; Turek, I.; Khmelevskyi, S.

    2017-01-01

    Roč. 96, č. 2 (2017), s. 1-5, č. článku 024432. ISSN 2469-9950 R&D Projects: GA ČR GA15-13436S Grant - others:GA MŠk(CZ) LM2015042; Ga MŠk(CZ) LM2015070 Institutional support: RVO:68378271 Keywords : Earth's core * electrical conductivity * spin-disorder resistivity * violation of Matthiessen rule Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 3.836, year: 2016

  8. Chemical Force Spectroscopy Evidence Supporting the Layer-by-Layer Model of Organic Matter Binding to Iron (oxy)Hydroxide Mineral Surfaces

    KAUST Repository

    Chassé , Alexander W.; Ohno, Tsutomu; Higgins, Steven R.; Amirbahman, Aria; Yildirim, Nadir; Parr, Thomas B.

    2015-01-01

    © 2015 American Chemical Society. The adsorption of dissolved organic matter (DOM) to metal (oxy)hydroxide mineral surfaces is a critical step for C sequestration in soils. Although equilibrium studies have described some of the factors controlling this process, the molecular-scale description of the adsorption process has been more limited. Chemical force spectroscopy revealed differing adhesion strengths of DOM extracted from three soils and a reference peat soil material to an iron (oxy)hydroxide mineral surface. The DOM was characterized using ultrahigh-resolution negative ion mode electrospray ionization Fourier Transform ion cyclotron resonance mass spectrometry. The results indicate that carboxyl-rich aromatic and N-containing aliphatic molecules of DOM are correlated with high adhesion forces. Increasing molecular mass was shown to decrease the adhesion force between the mineral surface and the DOM. Kendrick mass defect analysis suggests that mechanisms involving two carboxyl groups result in the most stable bond to the mineral surface. We conceptualize these results using a layer-by-layer "onion" model of organic matter stabilization on soil mineral surfaces.

  9. Hyperspectral surface materials map of quadrangle 3264, Naw Zad-Musa Qala (423) and Dihrawud (424) quadrangles, Afghanistan, showing iron-bearing minerals and other materials

    Science.gov (United States)

    King, Trude V.V.; Hoefen, Todd M.; Kokaly, Raymond F.; Livo, Keith E.; Johnson, Michaela R.; Giles, Stuart A.

    2013-01-01

    This map shows the spatial distribution of selected iron-bearing minerals and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. This map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Goethite and jarosite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  10. Hyperspectral surface materials map of quadrangle 3266, Uruzgan (519) and Moqur (520) quadrangles, Afghanistan, showing iron-bearing minerals and other materials

    Science.gov (United States)

    King, Trude V.V.; Hoefen, Todd M.; Kokaly, Raymond F.; Livo, Keith E.; Giles, Stuart A.; Johnson, Michaela R.

    2013-01-01

    This map shows the spatial distribution of selected iron-bearing minerals and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. This map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Goethite and jarosite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  11. Hyperspectral surface materials map of quadrangle 3464, Shahrak (411) and Kasi (412) quadrangles, Afghanistan, showing iron-bearing minerals and other materials

    Science.gov (United States)

    King, Trude V.V.; Hoefen, Todd M.; Kokaly, Raymond F.; Livo, Keith E.; Johnson, Michaela R.; Giles, Stuart A.

    2013-01-01

    This map shows the spatial distribution of selected iron-bearing minerals and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. This map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Goethite and jarosite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  12. Hyperspectral surface materials map of quadrangle 3466, La`l wa Sar Jangal (507) and Bamyan (508) quadrangles, Afghanistan, showing iron-bearing minerals and other materials

    Science.gov (United States)

    King, Trude V.V.; Hoefen, Todd M.; Kokaly, Raymond F.; Livo, Keith E.; Giles, Stuart A.; Johnson, Michaela R.

    2013-01-01

    This map shows the spatial distribution of selected iron-bearing minerals and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. This map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Goethite and jarosite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  13. Hyperspectral surface materials map of quadrangle 3260, Dasht-e-Chah-e-Mazar (419) and Anar Darah (420) quadrangles, Afghanistan, showing iron-bearing minerals and other materials

    Science.gov (United States)

    King, Trude V.V.; Hoefen, Todd M.; Kokaly, Raymond F.; Livo, Keith E.; Johnson, Michaela R.; Giles, Stuart A.

    2013-01-01

    This map shows the spatial distribution of selected iron-bearing minerals and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. This map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Goethite and jarosite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  14. Hyperspectral surface materials map of quadrangle 3470, Jalalabad (511) and Chaghasaray (512) quadrangles, Afghanistan, showing iron-bearing minerals and other materials

    Science.gov (United States)

    King, Trude V.V.; Hoefen, Todd M.; Kokaly, Raymond F.; Livo, Keith E.; Giles, Stuart A.; Johnson, Michaela R.

    2013-01-01

    This map shows the spatial distribution of selected iron-bearing minerals and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. This map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Goethite and jarosite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  15. Hyperspectral surface materials map of quadrangle 3570, Tagab-e-Munjan (505) and Asmar-Kamdesh (506) quadrangles, Afghanistan, showing iron-bearing minerals and other materials

    Science.gov (United States)

    King, Trude V.V.; Hoefen, Todd M.; Kokaly, Raymond F.; Livo, Keith E.; Johnson, Michaela R.; Giles, Stuart A.

    2013-01-01

    This map shows the spatial distribution of selected iron-bearing minerals and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. This map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Goethite and jarosite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  16. Hyperspectral surface materials map of quadrangle 3364, Pasaband (417) and Markaz-e Kajiran (418) quadrangles, Afghanistan, showing iron-bearing minerals and other materials

    Science.gov (United States)

    King, Trude V.V.; Hoefen, Todd M.; Kokaly, Raymond F.; Livo, Keith E.; Johnson, Michaela R.; Giles, Stuart A.

    2013-01-01

    This map shows the spatial distribution of selected iron-bearing minerals and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. This map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Goethite and jarosite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  17. Hyperspectral surface materials map of quadrangle 3462, Herat (409) and Chishti Sharif (410) quadrangles, Afghanistan, showing iron-bearing minerals and other materials

    Science.gov (United States)

    King, Trude V.V.; Hoefen, Todd M.; Kokaly, Raymond F.; Livo, Keith E.; Johnson, Michaela R.; Giles, Stuart A.

    2013-01-01

    This map shows the spatial distribution of selected iron-bearing minerals and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. This map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Goethite and jarosite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  18. Hyperspectral surface materials map of quadrangle 3468, Chak-e Wardak-Siyahgird (509) and Kabul (510) quadrangles, Afghanistan, showing iron-bearing minerals and other materials

    Science.gov (United States)

    King, Trude V.V.; Hoefen, Todd M.; Kokaly, Raymond F.; Livo, Keith E.; Giles, Stuart A.; Johnson, Michaela R.

    2013-01-01

    This map shows the spatial distribution of selected iron-bearing minerals and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. This map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Goethite and jarosite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  19. Hyperspectral surface materials map of quadrangle 3368, Ghazni (515) and Gardez (516) quadrangles, Afghanistan, showing iron-bearing minerals and other materials

    Science.gov (United States)

    King, Trude V.V.; Hoefen, Todd M.; Kokaly, Raymond F.; Livo, Keith E.; Johnson, Michaela R.; Giles, Stuart A.

    2013-01-01

    This map shows the spatial distribution of selected iron-bearing minerals and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. This map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Goethite and jarosite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  20. Hyperspectral surface materials map of quadrangle 3162, Chakhansur (603) and Kotalak (604) quadrangles, Afghanistan, showing iron-bearing minerals and other materials

    Science.gov (United States)

    King, Trude V.V.; Hoefen, Todd M.; Kokaly, Raymond F.; Livo, Keith E.; Johnson, Michaela R.; Giles, Stuart A.

    2013-01-01

    This map shows the spatial distribution of selected iron-bearing minerals and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. This map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Goethite and jarosite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  1. Hyperspectral surface materials map of quadrangle 3362, Shindand (415) and Tulak (416) quadrangles, Afghanistan, showing iron-bearing minerals and other materials

    Science.gov (United States)

    King, Trude V.V.; Hoefen, Todd M.; Kokaly, Raymond F.; Livo, Keith E.; Giles, Stuart A.; Johnson, Michaela R.

    2013-01-01

    This map shows the spatial distribution of selected iron-bearing minerals and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. This map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Goethite and jarosite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  2. Hyperspectral surface materials map of quadrangle 3366, Gizab (513) and Nawer (514) quadrangles, Afghanistan, showing iron-bearing minerals and other materials

    Science.gov (United States)

    King, Trude V.V.; Hoefen, Todd M.; Kokaly, Raymond F.; Livo, Keith E.; Johnson, Michaela R.; Giles, Stuart A.

    2013-01-01

    This map shows the spatial distribution of selected iron-bearing minerals and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. This map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Goethite and jarosite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  3. Hyperspectral surface materials map of quadrangle 3770, Faizabad (217) and Parkhaw (218) quadrangles, Afghanistan, showing iron-bearing minerals and other materials

    Science.gov (United States)

    King, Trude V.V.; Hoefen, Todd M.; Kokaly, Raymond F.; Livo, Keith E.; Giles, Stuart A.; Johnson, Michaela R.

    2013-01-01

    This map shows the spatial distribution of selected iron-bearing minerals and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. This map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Goethite and jarosite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  4. Hyperspectral surface materials map of quadrangle 3564, Jowand (405) and Gurziwan (406) quadrangles, Afghanistan, showing iron-bearing minerals and other materials

    Science.gov (United States)

    King, Trude V.V.; Hoefen, Todd M.; Kokaly, Raymond F.; Livo, Keith E.; Johnson, Michaela R.; Giles, Stuart A.

    2013-01-01

    This map shows the spatial distribution of selected iron-bearing minerals and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. This map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Goethite and jarosite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  5. Hyperspectral surface materials map of quadrangle 3166, Jaldak (701) and Maruf-Nawa (702) quadrangles, Afghanistan, showing iron-bearing minerals and other materials

    Science.gov (United States)

    King, Trude V.V.; Hoefen, Todd M.; Kokaly, Raymond F.; Livo, Keith E.; Giles, Stuart A.; Johnson, Michaela R.

    2013-01-01

    This map shows the spatial distribution of selected iron-bearing minerals and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. This map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Goethite and jarosite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  6. Hyperspectral surface materials map of quadrangle 3566, Sangcharak (501) and Sayghan-o-Kamard (502) quadrangles, Afghanistan, showing iron-bearing minerals and other material

    Science.gov (United States)

    King, Trude V.V.; Hoefen, Todd M.; Kokaly, Raymond F.; Livo, Keith E.; Giles, Stuart A.; Johnson, Michaela R.

    2013-01-01

    This map shows the spatial distribution of selected iron-bearing minerals and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. This map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Goethite and jarosite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  7. Hyperspectral surface materials map of quadrangle 3670, Jurm-Kishim (223) and Zebak (224) quadrangles, Afghanistan, showing iron-bearing minerals and other materials

    Science.gov (United States)

    King, Trude V.V.; Hoefen, Todd M.; Kokaly, Raymond F.; Livo, Keith E.; Johnson, Michaela R.; Giles, Stuart A.

    2013-01-01

    This map shows the spatial distribution of selected iron-bearing minerals and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. This map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Goethite and jarosite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  8. Hyperspectral surface materials map of quadrangle 3568, Pul-e Khumri (503) and Charikar (504) quadrangles, Afghanistan, showing iron-bearing minerals and other materials

    Science.gov (United States)

    King, Trude V.V.; Hoefen, Todd M.; Kokaly, Raymond F.; Livo, Keith E.; Johnson, Michaela R.; Giles, Stuart A.

    2013-01-01

    This map shows the spatial distribution of selected iron-bearing minerals and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. This map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Goethite and jarosite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  9. Hyperspectral surface materials map of quadrangle 3262, Farah (421) and Hokumat-e-pur-Chaman (422) quadrangles, Afghanistan, showing iron-bearing minerals and other materials

    Science.gov (United States)

    King, Trude V.V.; Hoefen, Todd M.; Kokaly, Raymond F.; Livo, Keith E.; Johnson, Michaela R.; Giles, Stuart A.

    2013-01-01

    This map shows the spatial distribution of selected iron-bearing minerals and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. This map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Goethite and jarosite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  10. Hyperspectral surface materials map of quadrangle 3164, Lashkar Gah (605) and Kandahar (606) quadrangles, Afghanistan, showing iron-bearing minerals and other materials

    Science.gov (United States)

    King, Trude V.V.; Hoefen, Todd M.; Kokaly, Raymond F.; Livo, Keith E.; Johnson, Michaela R.; Giles, Stuart A.

    2013-01-01

    This map shows the spatial distribution of selected iron-bearing minerals and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. This map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Goethite and jarosite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  11. Hyperspectral surface materials map of quadrangle 3562, Khawja-Jir (403) and Murghab (404) quadrangles, Afghanistan, showing iron-bearing minerals and other materials

    Science.gov (United States)

    King, Trude V.V.; Hoefen, Todd M.; Kokaly, Raymond F.; Livo, Keith E.; Johnson, Michaela R.; Giles, Stuart A.

    2013-01-01

    This map shows the spatial distribution of selected iron-bearing minerals and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. This map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Goethite and jarosite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  12. Hyperspectral Surface Materials Map of Quadrangle 3268, Khayr Kot (521) and Urgun (522) Quadrangles, Afghanistan, Showing Iron-bearing Minerals and Other Materials

    Science.gov (United States)

    King, Trude V.V.; Hoefen, Todd M.; Kokaly, Raymond F.; Livo, Keith E.; Giles, Stuart A.; Johnson, Michaela R.

    2013-01-01

    This map shows the spatial distribution of selected iron-bearing minerals and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. This map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Goethite and jarosite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  13. Chemical Force Spectroscopy Evidence Supporting the Layer-by-Layer Model of Organic Matter Binding to Iron (oxy)Hydroxide Mineral Surfaces

    KAUST Repository

    Chassé, Alexander W.

    2015-08-18

    © 2015 American Chemical Society. The adsorption of dissolved organic matter (DOM) to metal (oxy)hydroxide mineral surfaces is a critical step for C sequestration in soils. Although equilibrium studies have described some of the factors controlling this process, the molecular-scale description of the adsorption process has been more limited. Chemical force spectroscopy revealed differing adhesion strengths of DOM extracted from three soils and a reference peat soil material to an iron (oxy)hydroxide mineral surface. The DOM was characterized using ultrahigh-resolution negative ion mode electrospray ionization Fourier Transform ion cyclotron resonance mass spectrometry. The results indicate that carboxyl-rich aromatic and N-containing aliphatic molecules of DOM are correlated with high adhesion forces. Increasing molecular mass was shown to decrease the adhesion force between the mineral surface and the DOM. Kendrick mass defect analysis suggests that mechanisms involving two carboxyl groups result in the most stable bond to the mineral surface. We conceptualize these results using a layer-by-layer "onion" model of organic matter stabilization on soil mineral surfaces.

  14. Iron and zinc complexation in wild-type and ferritin-expressing wheat grain: implications for mineral transport into developing grain

    DEFF Research Database (Denmark)

    Neal, Andrew L; Geraki, Kalotina; Borg, Søren

    2013-01-01

    of modified complexation of both metals in transgenic grain overexpressing wheat ferritin. For zinc, there is a consistent doubling of the number of complexing phosphorus atoms. Although there is some EXAFS evidence for iron phytate in ferritin-expressing grain, there is also evidence of a structure lacking......We have used synchrotron-based X-ray fluorescence and absorption techniques to establish both metal distribution and complexation in mature wheat grains. In planta, extended X-ray absorption fine structure (EXAFS) spectroscopy reveals iron phytate and zinc phytate structures in aleurone cells...... of ferritin-expressing grains is quite different from that in wild-type grain. This may explain why the raised levels of minerals transported to the developing grain accumulate within the crease region of the transgenic grain....

  15. Absorption mechanisms for cationic and anionic mineral species on ferric iron polymer hydroxides and oxidation products of ferrous iron in aqueous media

    International Nuclear Information System (INIS)

    Gandon, Remi

    1982-01-01

    Adsorbents obtained by hydrolysing the Fe 3+ , 6H 2 O ion are made of polymers with aquo (H 2 O), hydroxo (-OH...) and oxo (...O...) ligands. Radioactive tracers reveal the importance of chemical mechanisms in adsorption phenomena on ferric oxide in aqueous media. Zn 2+ , Co 2+ and Mn 2+ cations are exchanged with hydrogen from hydroxo groups. CrO 4 2- , SeO 3 2- and Sb(OH) 6 - anions form covalent associations in place of iron ligands. The adsorption of hydrolyzed ions results in strong oxygen bridge bonds. In fresh water, Co and Mn participate alone in physical electrostatic adsorption. Iron II oxidation products generate chemical adsorptions. Zn 2+ and Sb(OH) 6 - associate with ferric hydroxides from oxidized Fe 2+ . 60 Co, 54 Mn and 51 Cr form covalent associations between unpaired 3d iron electrons and the adsorbed element. This process is not predominant with selenium IV or VI reduced to the metallic state or fixed on ferric hydroxide in the selenite form. These conclusions can be applied to pollutant analysis and to water purification and contribute to our understanding of the role of iron in the distribution of oligo-elements in aqueous media. (author) [fr

  16. Research on the development strategy of Pingdingshan iron and steel industry cluster with Wugang Company as the core

    Directory of Open Access Journals (Sweden)

    Wang Shuai

    2017-01-01

    Full Text Available Arouse the great potential of the industrial clusters will play a significant role in promoting the development of local WuGang company. The article takes the Pingdingshan City as the research object, who is a typical resource-based city and develops on the basis of the local resources of coal and iron ore, the core enterprise WuGang Company is a large state-owned enterprise based on the wide and thick steel plate production. Many problems also exit in the cluster innovation, company network construction, company cooperation. The article is from the perspective of steel industry cluster and cluster innovation. Firstly, the article introduces the correlation theory about the steel industry cluster and the basic development information of Pingdingshan steel industry cluster, and promotes the research purpose and meaning.The article will give the analysis to the problems from the Pingdingshan steel industry cluster and develop the reform proposals and development strategy according to the actual situation.

  17. Oxygen isotope exchange kinetics of mineral pairs in closed and open systems: Applications to problems of hydrothermal alteration of igneous rocks and Precambrian iron formations

    Science.gov (United States)

    Gregory, R.T.; Criss, R.E.; Taylor, H.P.

    1989-01-01

    heat-balance constraints, we can utilize the 18O 16O data on natural mineral assemblages to calculate the kinetic rate constants (k's) and the effective diffusion constants (D's) for mineral-H2O exchange: these calculated values (kqtz ??? 10-14, kfeld ??? 10-13-10-12) agree with experimental determinations of such constants. In nature, once the driving force or energy source for the external infiltrating fluid phase is removed, the disequilibrium mineral-pair arrays will either: (1) remain "frozen" in their existing state, if the temperatures are low enough, or (2) re-equilibrate along specific closed-system exchange vectors determined solely by the temperature path and the mineral modal proportions. Thus, modal mineralogical information is a particularly important parameter in both the open- and closed-system scenarios, and should in general always be reported in stable-isotopic studies of mineral assemblages. These concepts are applied to an analysis of 18O 16O systematics of gabbros (Plagioclase-clinopyroxene and plagioclase-amphibole pairs), granitic plutons (quartz-feldspar pairs), and Precambrian siliceous iron formations (quartz-magnetite pairs). In all these examples, striking regularities are observed on ??-?? and ??-?? plots, but we point out that ??-?? plots have many advantages over their equivalent ??-?? diagrams, as the latter are more susceptible to misinterpretation. Using the equations developed in this study, these regularities can be interpreted to give semiquantitative information on the exchange histories of these rocks subsequent to their formation. In particular, we present a new interpretation indicating that Precambrian cherty iron formations have in general undergone a complex fluid exchange history in which the iron oxide (magnetite precursor?) has exchanged much faster with low-temperature (< 400??C) fluids than has the relatively inert quartz. ?? 1989.

  18. Spectral variations in rocks and soils containing ferric iron hydroxide and(or) sulfate minerals as seen by AVIRIS and laboratory spectroscopy

    Science.gov (United States)

    Rockwell, Barnaby W.

    2004-01-01

    Analysis of Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) data covering the Big Rock Candy Mountain area of the Marysvale volcanic field, west-central Utah, identified abundant rocks and soils bearing jarosite, goethite, and chlorite associated with volcanic rocks altered to propylitic grade during the Miocene (2321 Ma). Propylitically-altered rocks rich in pyrite associated with the relict feeder zones of convecting, shallow hydrothermal systems are currently undergoing supergene oxidation to natrojarosite, kaolinite, and gypsum. Goethite coatings are forming at the expense of jarosite where most pyrite has been consumed through oxidation in alluvium derived from pyrite-bearing zones. Spectral variations in the goethite-bearing rocks that resemble variations found in reference library samples of goethites of varying grain size were observed in the AVIRIS data. Rocks outside of the feeder zones have relatively low pyrite content and are characterized by chlorite, epidote, and calcite, with local copper-bearing quartz-calcite veins. Iron-bearing minerals in these rocks are weathering directly to goethite. Laboratory spectral analyses were applied to samples of iron-bearing rock outcrops and alluvium collected from the area to determine the accuracy of the AVIRIS-based mineral identification. The accuracy of the iron mineral identification results obtained by analysis of the AVIRIS data was confirmed. In general, the AVIRIS analysis results were accurate in identifying medium-grained goethite, coarse-grained goethite, medium- to coarse-grained goethite with trace jarosite, and mixtures of goethite and jarosite. However, rock fragments from alluvial areas identified as thin coatings of goethite with the AVIRIS data were found to consist mainly of medium- to coarse-grained goethite based on spectral characteristics in the visible and near-infrared. To determine if goethite abundance contributed to the spectral variations observed in goethite-bearing rocks

  19. A study of uranium series disequilibrium in core profiles and mineral separates from the samples of Lac du Bonnet granite from the URL site, Pinawa, Manitoba, Canada

    International Nuclear Information System (INIS)

    Ivanovich, M.; Longworth, G.; Wilkins, M.A.; Hasler, S.E.

    1987-12-01

    Uranium series disequilibrium measurements of actinide activities and activity ratios have been used to study the geochemical history of Lac du Bonnet granite, from the URL site, Pinawa, Canada. Measurements on core profiles between fractured surfaces and the parent rock show that the granite underwent high temperature events several million years ago, followed by more recent low temperature events within the last million years. The main locations for the rock/water interaction and exchange of actinides are the fracture surfaces. The results of similar measurements on separated mineral phases show that the 'soft' minerals such as biotite and feldspar are more vulnerable to weathering than the 'hard' accessory minerals such as zircon. (author)

  20. Microbial reduction of structural iron in interstratified illite-smectite minerals by a sulfate-reducing bacterium.

    Science.gov (United States)

    Liu, D; Dong, H; Bishop, M E; Zhang, J; Wang, H; Xie, S; Wang, S; Huang, L; Eberl, D D

    2012-03-01

    Clay minerals are ubiquitous in soils, sediments, and sedimentary rocks and could coexist with sulfate-reducing bacteria (SRB) in anoxic environments, however, the interactions of clay minerals and SRB are not well understood. The objective of this study was to understand the reduction rate and capacity of structural Fe(III) in dioctahedral clay minerals by a mesophilic SRB, Desulfovibrio vulgaris and the potential role in catalyzing smectite illitization. Bioreduction experiments were performed in batch systems, where four different clay minerals (nontronite NAu-2, mixed-layer illite-smectite RAr-1 and ISCz-1, and illite IMt-1) were exposed to D. vulgaris in a non-growth medium with and without anthraquinone-2,6-disulfonate (AQDS) and sulfate. Our results demonstrated that D. vulgaris was able to reduce structural Fe(III) in these clay minerals, and AQDS enhanced the reduction rate and extent. In the presence of AQDS, sulfate had little effect on Fe(III) bioreduction. In the absence of AQDS, sulfate increased the reduction rate and capacity, suggesting that sulfide produced during sulfate reduction reacted with the phyllosilicate Fe(III). The extent of bioreduction of structural Fe(III) in the clay minerals was positively correlated with the percentage of smectite and mineral surface area of these minerals. X-ray diffraction, and scanning and transmission electron microscopy results confirmed formation of illite after bioreduction. These data collectively showed that D. vulgaris could promote smectite illitization through reduction of structural Fe(III) in clay minerals. © 2011 Blackwell Publishing Ltd.

  1. Iron supplements (image)

    Science.gov (United States)

    The mineral iron is an essential nutrient for humans because it is part of blood cells, which carry oxygen to all body cells. There is no conclusive evidence that iron supplements contribute to heart attacks.

  2. Vibrational, X-ray absorption, and Mössbauer spectra of sulfate minerals from the weathered massive sulfide deposit at Iron Mountain, California

    Science.gov (United States)

    Majzlan, Juraj; Alpers, Charles N.; Bender Koch, Christian; McCleskey, R. Blaine; Myneni, Satish B.C.; Neil, John M.

    2014-01-01

    The Iron Mountain Mine Superfund site in California is a prime example of an acid mine drainage (AMD) system with well developed assemblages of sulfate minerals typical for such settings. Here we present and discuss the vibrational (infrared), X-ray absorption, and Mössbauer spectra of a number of these phases, augmented by spectra of a few synthetic sulfates related to the AMD phases. The minerals and related phases studied in this work are (in order of increasing Fe2O3/FeO): szomolnokite, rozenite, siderotil, halotrichite, römerite, voltaite, copiapite, monoclinic Fe2(SO4)3, Fe2(SO4)3·5H2O, kornelite, coquimbite, Fe(SO4)(OH), jarosite and rhomboclase. Fourier transform infrared spectra in the region 750–4000 cm−1 are presented for all studied phases. Position of the FTIR bands is discussed in terms of the vibrations of sulfate ions, hydroxyl groups, and water molecules. Sulfur K-edge X-ray absorption near-edge structure (XANES) spectra were collected for selected samples. The feature of greatest interest is a series of weak pre-edge peaks whose position is determined by the number of bridging oxygen atoms between Fe3+ octahedra and sulfate tetrahedra. Mössbauer spectra of selected samples were obtained at room temperature and 80 K for ferric minerals jarosite and rhomboclase and mixed ferric–ferrous minerals römerite, voltaite, and copiapite. Values of Fe2+/[Fe2+ + Fe3+] determined by Mössbauer spectroscopy agree well with those determined by wet chemical analysis. The data presented here can be used as standards in spectroscopic work where spectra of well-characterized compounds are required to identify complex mixtures of minerals and related phases.

  3. The redox properties of the natural iron-bearing clay mineral ferruginous smectite SWA-1: a combined electrochemical and spectroscopic study

    International Nuclear Information System (INIS)

    Gorski, Christopher A.; Voegelin, Andreas; Sander, Michael; Hofstetter, Thomas B.

    2012-01-01

    Document available in extended abstract form only. Iron-bearing clay minerals are ubiquitous in the environment and clay-mineral-based materials have been proposed to be part of backfill material in nuclear waste repositories. Laboratory and field studies have confirmed that structural iron (Fe) in clay minerals participates in redox reactions with organic pollutants, metals, and radionuclides, thus influencing their transport and reactivity. Knowledge of the redox properties of Fe-bearing clay minerals is therefore essential for understanding and predicting the fate, mobility, and bioavailability subsurface contaminants. A quantitative understanding of clay mineral redox behavior remains lacking, however, due to constraints in previous experimental approaches and the complex structural changes that accompany changes in the Fe oxidation state. This work provides a quantitative means for measuring the redox properties of Fe-bearing clay minerals, which can be applied to both field and laboratory studies tracking radionuclide-clay mineral redox reactions. Here we use mediated electrochemical reduction and oxidation to determine the electron accepting and donating capacities of several natural Fe-bearing clay minerals with different structural Fe content (2.3 to 21 wt-%) and varied redox histories. Results indicate that the fraction of redox-active Fe in clay minerals is mineral-dependent, and is linked to the thermodynamics of reduction and oxidation as well as to the ability of clay minerals to conduct electrons and facilitate structural re-arrangements required to maintain charge balance. The reduction potential (E H ) characteristics of a natural ferruginous smectite (SWa-1) were further characterized as a function of solution conditions and repeated Fe reduction and oxidation cycles. SWa-1 samples were analyzed with Moessbauer spectroscopy (MS) and X-ray absorption spectroscopy (XAS) to link observed redox potential behavior to structural properties and changes

  4. Chemistry of Selected Core Samples, Concentrate, Tailings, and Tailings Pond Waters: Pea Ridge Iron (-Lanthanide-Gold) Deposit, Washington County, Missouri

    Science.gov (United States)

    Grauch, Richard I.; Verplanck, Philip L.; Seeger, Cheryl M.; Budahn, James R.; Van Gosen, Bradley S.

    2010-01-01

    The Minerals at Risk and for Emerging Technologies Project of the U.S. Geological Survey (USGS) Mineral Resources Program is examining potential sources of lanthanide elements (rare earth elements) as part of its objective to provide up-to-date geologic information regarding mineral commodities likely to have increased demand in the near term. As part of the examination effort, a short visit was made to the Pea Ridge iron (-lanthanide-gold) deposit, Washington County, Missouri in October 2008. The deposit, currently owned by Wings Enterprises, Inc. of St. Louis, Missouri (Wings), contains concentrations of lanthanides that may be economic as a primary product or as a byproduct of iron ore production. This report tabulates the results of chemical analyses of the Pea Ridge samples and compares rare earth elements contents for world class lanthanide deposits with those of the Pea Ridge deposit. The data presented for the Pea Ridge deposit are preliminary and include some company data that have not been verified by the USGS or by the Missouri Department of Natural Resources, Division of Geology and Land Survey (DGLS), Geological Survey Program (MGS). The inclusion of company data is for comparative purposes only and does not imply an endorsement by either the USGS or MGS.

  5. Removal of uranium(VI) from the aqueous phase by iron(II) minerals in presence of bicarbonate

    Energy Technology Data Exchange (ETDEWEB)

    Regenspurg, Simona, E-mail: regens@gfz-potsdam.de [Industrial Ecology, Royal Institute of Technology (KTH), SE 10044 Stockholm (Sweden); Schild, Dieter; Schaefer, Thorsten; Huber, Florian [Institut fuer Nukleare Entsorgung (INE), Forschungszentrum Karlsruhe, 76344 Eggenstein-Leopoldshafen (Germany); Malmstroem, Maria E. [Industrial Ecology, Royal Institute of Technology (KTH), SE 10044 Stockholm (Sweden)

    2009-09-15

    Uranium(VI) mobility in groundwater is strongly affected by sorption of mobile U(VI) species (e.g. uranyl, UO{sub 2}{sup 2+}) to mineral surfaces, precipitation of U(VI) compounds, such as schoepite (UO{sub 2}){sub 4}O(OH){sub 6}.6H{sub 2}O), and by reduction to U(IV), forming sparingly soluble phases (uraninite; UO{sub 2}). The latter pathway, in particular, would be very efficient for long-term immobilization of U. In nature, Fe(II) is an important reducing agent for U(VI) because it frequently occurs either dissolved in natural waters, sorbed to matrix minerals, or structurally bound in many minerals. Redox reactions between U(VI) and Fe(II) depend not only on the availability of Fe(II) in the environment, but also on the chemical conditions in the aqueous solution. Under natural groundwater condition U(VI) forms complexes with many anionic ligands, which strongly affect its speciation. Carbonate, in particular, is known to form stable complexes with U, raising the question, if U(VI), when complexed by carbonate, can be reduced to UO{sub 2}. The goal of this study was to find out if Fe(II) when structurally bound in a mineral (as magnetite, Fe{sub 3}O{sub 4}) or sorbed to a mineral surface (as corundum, Al{sub 2}O{sub 3}) can reduce U(VI) to U(IV) in the presence of HCO{sub 3}{sup -}. Batch experiments were conducted under anaerobic conditions to observe U removal from the aqueous phase by the two minerals depending on HCO{sub 3}{sup -} addition (1 mM), U concentration (0.01-30 {mu}M) and pH value (6-10). Immediately after the experiments, the mineral surfaces were analyzed by X-ray photoelectron spectroscopy (XPS) to obtain information on the redox state of U bound to the solid surfaces. XPS results gave evidence that U(VI) can be reduced both by magnetite and by corundum amended with Fe(II). In the presence of HCO{sub 3}{sup -} the amount of reduced U on the mineral surfaces increased compared to carbonate-free solutions. This can be explained by the formation

  6. Iron and stony-iron meteorites

    DEFF Research Database (Denmark)

    Ruzicka, Alex M.; Haack, Henning; Chabot, Nancy L.

    2017-01-01

    By far most of the melted and differentiated planetesimals that have been sampled as meteorites are metal-rich iron meteorites or stony iron meteorites. The parent asteroids of these meteorites accreted early and differentiated shortly after the solar system formed, producing some of the oldest...... and interpretations for iron and stony iron meteorites (Plate 13.1). Such meteorites provide important constraints on the nature of metal-silicate separation and mixing in planetesimals undergoing partial to complete differentiation. They include iron meteorites that formed by the solidification of cores...... (fractionally crystallized irons), irons in which partly molten metal and silicates of diverse types were mixed together (silicate-bearing irons), stony irons in which partly molten metal and olivine from cores and mantles were mixed together (pallasites), and stony irons in which partly molten metal...

  7. Bioavailability of mineral-bound iron to a snow algae-bacteria co-culture and implications for albedo-altering snow algae blooms.

    Science.gov (United States)

    Harrold, Z R; Hausrath, E M; Garcia, A H; Murray, A E; Tschauner, O; Raymond, J; Huang, S

    2018-01-26

    Snow algae can form large-scale blooms across the snowpack surface and near-surface environments. These pigmented blooms can decrease snow albedo, increase local melt rates, and may impact the global heat budget and water cycle. Yet, underlying causes for the geospatial occurrence of these blooms remain unconstrained. One possible factor contributing to snow algae blooms is the presence of mineral dust as a micronutrient source. We investigated the bioavailability of iron (Fe) -bearing minerals, including forsterite (Fo 90 , Mg 1.8 Fe 0.2 SiO 4 ), goethite, smectite and pyrite as Fe sources for a Chloromonas brevispina - bacteria co-culture through laboratory-based experimentation. Fo 90 was capable of stimulating snow algal growth and increased the algal growth rate in otherwise Fe-depleted co-cultures. Fo 90 -bearing systems also exhibited a decrease in bacteria:algae ratios compared to Fe-depleted conditions, suggesting a shift in microbial community structure. The C. brevispina co-culture also increased the rate of Fo 90 dissolution relative to an abiotic control. Analysis of 16S rRNA genes in the co-culture identified Gammaproteobacteria , Betaprotoeobacteria and Sphingobacteria , all of which are commonly found in snow and ice environments. Archaea were not detected. Collimonas and Pseudomonas , which are known to enhance mineral weathering rates, comprised two of the top eight (> 1 %) OTUs. These data provide unequivocal evidence that mineral dust can support elevated snow algae growth under otherwise Fe-depleted growth conditions, and that snow algae can enhance mineral dissolution under these conditions. IMPORTANCE Fe, a key micronutrient for photosynthetic growth, is necessary to support the formation of high-density snow algae blooms. The laboratory experiments described herein allow for a systematic investigation of snow algae-bacteria-mineral interactions and their ability to mobilize and uptake mineral-bound Fe. Results provide unequivocal and

  8. Reconstruction of late Quaternary monsoon oscillations based on clay mineral proxies using sediment cores from the western margin of India

    Digital Repository Service at National Institute of Oceanography (India)

    Thamban, M.; Rao, V.P.; Schneider, R.R.

    sites were from the hinterland rocks and soils. Careful evaluations of several factors that could complicate the clay distribution in marine environment indicate that the clay mineral parameters can be used as proxies for the intensity of summer monsoon...

  9. Zero-valent iron treatment of dark brown colored coffee effluent: Contributions of a core-shell structure to pollutant removals.

    Science.gov (United States)

    Tomizawa, Mayuka; Kurosu, Shunji; Kobayashi, Maki; Kawase, Yoshinori

    2016-12-01

    The decolorization and total organic carbon (TOC) removal of dark brown colored coffee effluent by zero-valent iron (ZVI) have been systematically examined with solution pH of 3.0, 4.0, 6.0 and 8.0 under oxic and anoxic conditions. The optimal decolorization and TOC removal were obtained at pH 8.0 with oxic condition. The maximum efficiencies of decolorization and TOC removal were 92.6 and 60.2%, respectively. ZVI presented potential properties for pollutant removal at nearly neutral pH because of its core-shell structure in which shell or iron oxide/hydroxide layer on ZVI surface dominated the decolorization and TOC removal of coffee effluent. To elucidate the contribution of the core-shell structure to removals of color and TOC at the optimal condition, the characterization of ZVI surface by scanning electron microscopy (SEM) with an energy dispersive X-ray spectroscope (EDS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) was conducted. It was confirmed that the core-shell structure was formed and the shell on ZVI particulate surface and the precipitates formed during the course of ZVI treatment consisted of iron oxides and hydroxides. They were significantly responsible for decolorization and TOC removal of coffee effluent via adsorption to shell on ZVI surface and inclusion into the precipitates rather than the oxidative degradation by OH radicals and the reduction by emitted electrons. The presence of dissolved oxygen (DO) enhanced the formation of the core-shell structure and as a result improved the efficiency of ZVI treatment for the removal of colored components in coffee effluents. ZVI was found to be an efficient material toward the treatment of coffee effluents. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Applications of surface analysis in the environmental sciences: dehalogenation of chlorocarbons with zero-valent iron and iron-containing mineral surfaces

    Energy Technology Data Exchange (ETDEWEB)

    McGuire, Molly M.; Carlson, Daniel L.; Vikesland, Peter J.; Kohn, Tamar; Grenier, Adam C.; Langley, Laura A.; Roberts, A. Lynn; Fairbrother, D. Howard

    2003-10-31

    Halogenated organic compounds are common pollutants in groundwater. Consequently, there is widespread interest in understanding the reactions of these compounds in the environment and developing remediation strategies. One area of ongoing research involves the reductive dechlorination of organohalides with zero-valent metals or metal sulfide minerals. These processes have been studied almost exclusively from the perspective of the aqueous phase. In this paper we illustrate the utility of surface analysis techniques, including electron spectroscopies, vibrational spectroscopies, and atomic force microscopy in elucidating the roles played by the surface. A dual analysis approach to the study of reductive dechlorination, combining traditional solution phase analysis with surface analytical techniques, also is demonstrated using a liquid cell coupled to an ultrahigh vacuum surface analysis chamber.

  11. Aqueous corrosion of phosphide minerals from iron meteorites: a highly reactive source of prebiotic phosphorus on the surface of the early Earth.

    Science.gov (United States)

    Pasek, Matthew A; Lauretta, Dante S

    2005-08-01

    We present the results of an experimental study of aqueous corrosion of Fe-phosphide under conditions relevant to the early Earth. The results strongly suggest that iron meteorites were an important source of reactive phosphorus (P), a requirement for the formation of P-based life. We further demonstrate that iron meteorites were an abundant source of phosphide minerals early in Earth history. Phosphide corrosion was studied in five different solutions: deionized water, deionized water buffered with sodium bicarbonate, deionized water with dissolved magnesium and calcium chlorides, deionized water containing ethanol and acetic acid, and deionized water containing the chlorides, ethanol, and acetic acid. Experiments were performed in the presence of both air and pure Ar gas to evaluate the effect of atmospheric chemistry. Phosphide corrosion in deionized water results in a metastable mixture of mixed-valence, P-bearing ions including pyrophosphate and triphosphate, key components for metabolism in modern life. In a pH-buffered solution of NaHCO(3), the condensed and reduced species diphosphonate is an abundant corrosion product. Corrosion in ethanol- and acetic acid-containing solutions yields additional P-bearing organic molecules, including acetyl phosphonate and a cyclic triphosphorus molecule. Phosphonate is a major corrosion product of all experiments and is the only P-bearing molecule that persists in solutions with high concentrations of magnesium and calcium chlorides, which suggests that phosphonate may have been a primitive oceanic source of P. The stability and reactivity of phosphonate and hypophosphite in solution were investigated to elucidate reaction mechanisms and the role of mineral catalysts on P-solution chemistry. Phosphonate oxidation is rapid in the presence of Fe metal but negligible in the presence of magnetite and in the control sample. The rate of hypophosphite oxidation is independent of reaction substrate.

  12. Cold Extrusion but Not Coating Affects Iron Bioavailability from Fortified Rice in Young Women and Is Associated with Modifications in Starch Microstructure and Mineral Retention during Cooking.

    Science.gov (United States)

    Hackl, Laura; Speich, Cornelia; Zeder, Christophe; Sánchez-Ferrer, Antoni; Adelmann, Horst; de Pee, Saskia; Tay, Fabian; Zimmermann, Michael B; Moretti, Diego

    2017-12-01

    retentions >80%, and cooking in excess water did not affect iron retention from hot-extruded rice but caused iron losses of 25% from CER and COR. Distinct variations in starch microstructure were found in CER and HER1. Conclusions: Iron absorption was 64% higher from CER than from hot-extruded rice, with no difference between COR compared with hot-extruded rice. Lower extrusion temperatures may generate a more readily digestible starch structure, allowing for greater iron release in vivo but lower mineral retention during cooking. This trial was registered at clinicaltrials.gov as NCT02176759. © 2017 American Society for Nutrition.

  13. Enhanced bio-compatibility of ferrofluids of self-assembled superparamagnetic iron oxide-silica core-shell nanoparticles

    Digital Repository Service at National Institute of Oceanography (India)

    Narayanan, T.N.; Mary, A.P.R.; Swalih, P.K.A.; Kumar, D.S.; Makarov, D.; Albrecht, M.; Puthumana, J.; Anas, A.; Anantharaman, A.

    -interacting, monodispersed and hence the synthesis of such nanostructures has great relevance in the realm of nanoscience. Silica-coated superparamagnetic iron oxide nanoparticles based ferrofluids were prepared using polyethylene glycol as carrier fluid by employing a...

  14. Geologic field notes and geochemical analyses of outcrop and drill core from Mesoproterozoic rocks and iron-oxide deposits and prospects of southeast Missouri

    Science.gov (United States)

    Day, Warren C.; Granitto, Matthew

    2014-01-01

    The U.S. Geological Survey, in cooperation with the Missouri Department of Natural Resources/Missouri Geological Survey, undertook a study from 1988 to 1994 on the iron-oxide deposits and their host Mesoproterozoic igneous rocks in southeastern Missouri. The project resulted in an improvement of our understanding of the geologic setting, mode of formation, and the composition of many of the known deposits and prospects and the associated rocks of the St. Francois terrane in Missouri. The goal for this earlier work was to allow the comparison of Missouri iron-oxide deposits in context with other iron oxide-copper ± uranium (IOCG) types of mineral deposits observed globally. The raw geochemical analyses were released originally through the USGS National Geochemical Database (NGDB, http://mrdata.usgs.gov). The data presented herein offers all of the field notes, locations, rock descriptions, and geochemical analyses in a coherent package to facilitate new research efforts in IOCG deposit types. The data are provided in both Microsoft Excel (Version Office 2010) spreadsheet format (*.xlsx) and MS-DOS text formats (*.txt) for ease of use by numerous computer programs.

  15. Characteristics and adaptability of iron- and sulfur-oxidizing microorganisms used for the recovery of metals from minerals and their concentrates

    Directory of Open Access Journals (Sweden)

    Rawlings Douglas E

    2005-05-01

    Full Text Available Abstract Microorganisms are used in large-scale heap or tank aeration processes for the commercial extraction of a variety of metals from their ores or concentrates. These include copper, cobalt, gold and, in the past, uranium. The metal solubilization processes are considered to be largely chemical with the microorganisms providing the chemicals and the space (exopolysaccharide layer where the mineral dissolution reactions occur. Temperatures at which these processes are carried out can vary from ambient to 80°C and the types of organisms present depends to a large extent on the process temperature used. Irrespective of the operation temperature, biomining microbes have several characteristics in common. One shared characteristic is their ability to produce the ferric iron and sulfuric acid required to degrade the mineral and facilitate metal recovery. Other characteristics are their ability to grow autotrophically, their acid-tolerance and their inherent metal resistance or ability to acquire metal resistance. Although the microorganisms that drive the process have the above properties in common, biomining microbes usually occur in consortia in which cross-feeding may occur such that a combination of microbes including some with heterotrophic tendencies may contribute to the efficiency of the process. The remarkable adaptability of these organisms is assisted by several of the processes being continuous-flow systems that enable the continual selection of microorganisms that are more efficient at mineral degradation. Adaptability is also assisted by the processes being open and non-sterile thereby permitting new organisms to enter. This openness allows for the possibility of new genes that improve cell fitness to be selected from the horizontal gene pool. Characteristics that biomining microorganisms have in common and examples of their remarkable adaptability are described.

  16. Trace Mineral Losses in Sweat

    National Research Council Canada - National Science Library

    Chinevere, Troy D; McClung, James P; Cheuvront, Samuel N

    2007-01-01

    Copper, iron and zinc are nutritionally essential trace minerals that confer vital biological roles including the maintenance of cell structure and integrity, regulation of metabolism, immune function...

  17. Manganese-oxide minerals in fractures of the Crater Flat Tuff in drill core USW G-4, Yucca Mountain, Nevada

    International Nuclear Information System (INIS)

    Carlos, B.A.; Bish, D.L.; Chipera, S.J.

    1990-07-01

    The Crater Flat Tuff is almost entirely below the water table in drill hole USW G-4 at Yucca Mountain, Nevada. Manganese-oxide minerals from the Crater Flat Tuff in USW G-4 were studied using optical, scanning electron microscopic, electron microprobe, and x-ray powder diffraction methods to determine their distribution, mineralogy, and chemistry. Manganese-oxide minerals coat fractures in all three members of the Crater Flat Tuff (Prow Pass, Bullfrog, and Tram), but they are most abundant in fractures in the densely welded devitrified intervals of these members. The coatings are mostly of the cryptomelane/hollandite mineral group, but the chemistry of these coatings varies considerably. Some of the chemical variations, particularly the presence of calcium, sodium, and strontium, can be explained by admixture with todorokite, seen in some x-ray powder diffraction patterns. Other chemical variations, particularly between Ba and Pb, demonstrate that considerable substitution of Pb for Ba occurs in hollandite. Manganese-oxide coatings are common in the 10-m interval that produced 75% of the water pumped from USW G-4 in a flow survey in 1983. Their presence in water-producing zones suggests that manganese oxides may exert a significant chemical effect on groundwater beneath Yucca Mountain. In particular, the ability of the manganese oxides found at Yucca Mountain to be easily reduced suggests that they may affect the redox conditions of the groundwater and may oxidize dissolved or suspended species. Although the Mn oxides at Yucca Mountain have low exchange capacities, these minerals may retard the migration of some radionuclides, particularly the actinides, through scavenging and coprecipitation. 23 refs., 21 figs., 2 tabs

  18. Spatial and temporal zoning of hydrothermal alteration and mineralization in the Sossego iron oxide-copper-gold deposit, Carajás Mineral Province, Brazil: Paragenesis and stable isotope constraints

    Science.gov (United States)

    Monteiro, Lena V.S.; Xavier, R.P.; Carvalho, E.R.; Hitzman, M.W.; Johnson, C.A.; Souza, Filho C.R.; Torresi, I.

    2008-01-01

    The Sossego iron oxide–copper–gold deposit (245 Mt @ 1.1% Cu, 0.28 g/t Au) in the Carajás Mineral Province of Brazil consists of two major groups of orebodies (Pista–Sequeirinho–Baiano and Sossego–Curral) with distinct alteration assemblages that are separated from each other by a major high angle fault. The deposit is located along a regional WNW–ESE-striking shear zone that defines the contact between metavolcano–sedimentary units of the ∼2.76 Ga Itacaiúnas Supergroup and tonalitic to trondhjemitic gneisses and migmatites of the ∼2.8 Ga Xingu Complex. The deposit is hosted by granite, granophyric granite, gabbro, and felsic metavolcanic rocks. The Pista–Sequeirinho–Baiano orebodies have undergone regional sodic (albite–hematite) alteration and later sodic–calcic (actinolite-rich) alteration associated with the formation of massive magnetite–(apatite) bodies. Both these alteration assemblages display ductile to ductile–brittle fabrics. They are cut by spatially restricted zones of potassic (biotite and potassium feldspar) alteration that grades outward to chlorite-rich assemblages. The Sossego–Curral orebodies contain weakly developed early albitic alteration and very poorly developed subsequent calcic–sodic alteration. These orebodies contain well-developed potassic alteration assemblages that were formed during brittle deformation that resulted in the formation of breccia bodies. Breccia matrix commonly displays coarse mineral infill suggestive of growth into open space. Sulfides in both groups of deposits were precipitated first with potassic alteration and more importantly with a later assemblage of calcite–quartz–epidote–chlorite. In the Sequeirinho orebodies, sulfides range from undeformed to deformed; sulfides in the Sossego–Curral orebodies are undeformed. Very late, weakly mineralized hydrolytic alteration is present in the Sossego/Currral orebodies. The sulfide assemblage is dominated by chalcopyrite with

  19. Comparative performance of fluorescent iron-core ballasts and electronic ballasts. Rendement comparatif des ballasts a noyau de fer et des ballasts electroniques pour eclairage fluorescent

    Energy Technology Data Exchange (ETDEWEB)

    Pasini, I

    1987-01-01

    Commercially available one- and two-lamp fluorescent luminaires were tested, and a number of electrical parameters were measured using varying combinations of lamps and either iron-core or electronic ballasts. Comprehensive photometric tests and thermal measurements were also conducted. The test results were tabulated and compared. The performance of the iron-core ballasts was found to be sufficiently close to nominally rated values to not raise concerns. Results from testing the electronic ballasts showed that the user has to be careful when selecting these ballasts, as they far exceed standard specification limits for current and voltage crest factors. All other electrical, photometric and thermal parameters are within accepted levels. An economic analysis was undertaken to determine cost benefits and payback periods for using electronic ballasts, the use of which will result in higher efficiency and lower power consumption. A project life of 20 years was assumed, and analysis was run for a power cost of $0.04/kWh. A unit made by Fyrnetics showed the lowest total annual owning and operating costs and had a payback period of 12.1 years. 13 figs., 13 tabs.

  20. Iron and stony-iron meteorites

    DEFF Research Database (Denmark)

    Benedix, Gretchen K.; Haack, Henning; McCoy, T. J.

    2014-01-01

    Without iron and stony-iron meteorites, our chances of ever sampling the deep interior of a differentiated planetary object would be next to nil. Although we live on a planet with a very substantial core, we will never be able to sample it. Fortunately, asteroid collisions provide us with a rich...... sampling of the deep interiors of differentiated asteroids. Iron and stony-iron meteorites are fragments of a large number of asteroids that underwent significant geological processing in the early solar system. Parent bodies of iron and some stony-iron meteorites completed a geological evolution similar...... to that continuing on Earth – although on much smaller length- and timescales – with melting of the metal and silicates; differentiation into core, mantle, and crust; and probably extensive volcanism. Iron and stony-iron meteorites are our only available analogues to materials found in the deep interiors of Earth...

  1. Magnetic properties of iron/graphite core-shell nanoparticles prepared by annealing of Fe-C-N-based nanocomposite

    Czech Academy of Sciences Publication Activity Database

    David, Bohumil; Pizúrová, Naděžda; Schneeweiss, Oldřich; Bezdička, Petr; Alexandrescu, R.; Morjan, I.; Cruneteanu, A.; Voicu, I.

    290-291, - (2005), s. 179-182 ISSN 0304-8853 R&D Projects: GA ČR(CZ) GA202/04/0221; GA AV ČR(CZ) KSK1010104 Institutional research plan: CEZ:AV0Z20410507 Keywords : magnetism * iron * nanoparticle Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.985, year: 2005

  2. Stability of mineral fibres in contact with human cell cultures. An in situ μXANES, μXRD and XRF iron mapping study.

    Science.gov (United States)

    Pollastri, Simone; Gualtieri, Alessandro F; Vigliaturo, Ruggero; Ignatyev, Konstantin; Strafella, Elisabetta; Pugnaloni, Armanda; Croce, Alessandro

    2016-12-01

    Relevant mineral fibres of social and economic importance (chrysotile UICC, crocidolite UICC and a fibrous erionite from Jersey, Nevada, USA) were put in contact with cultured diploid human non-tumorigenic bronchial epithelial (Beas2B) and pleural transformed mesothelial (MeT5A) cells to test their cytotoxicity. Slides of each sample at different contact times up to 96 h were studied in situ using synchrotron XRF, μ-XRD and μ-XAS (I18 beamline, Diamond Light Source, UK) and TEM investigations. XRF maps of samples treated for 96 h evidenced that iron is still present within the chrysotile and crocidolite fibres and retained at the surface of the erionite fibres, indicating its null to minor mobilization in contact with cell media; this picture was confirmed by the results of XANES pre-edge analyses. μ-XRD and TEM data indicate greater morphological and crystallinity modifications occurring in chrysotile, whereas crocidolite and erionite show to be resistant in the biological environment. The contact of chrysotile with the cell cultures seems to lead to earlier amorphization, interpreted as the first dissolution step of these fibres. The formation of such silica-rich fibre skeleton may prompt the production of HO in synergy with surface iron species and could indicate that chrysotile may be much more reactive and cytotoxic in vitro in the (very) short term whereas the activity of crocidolite and erionite would be much more sluggish but persistent in the long term. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Comparative study of the iron cores in human liver ferritin, its pharmaceutical models and ferritin in chicken liver and spleen tissues using Moessbauer spectroscopy with a high velocity resolution

    Energy Technology Data Exchange (ETDEWEB)

    Alenkina, I.V.; Semionkin, V.A. [Faculty of Physical Techniques and Devices for Quality Control, Ural Federal University, Ekaterinburg (Russian Federation); Faculty of Experimental Physics, Ural Federal University, Ekaterinburg (Russian Federation); Oshtrakh, M.I. [Faculty of Physical Techniques and Devices for Quality Control, Ural Federal University, Ekaterinburg (Russian Federation); Klepova, Yu.V.; Sadovnikov, N.V. [Faculty of Physiology and Biotechnology, Ural State Agricultural Academy, Ekaterinburg, (Russian Federation); Dubiel, S.M. [Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, Krakow (Poland)

    2011-07-01

    Full text: Application of the Moessbauer spectroscopy with a high velocity resolution (4096 channels) for a study of iron-containing biological species is of great interest. Improving the velocity resolution allows to reveal small variations in the electronic structure of iron, and to obtain hyperfine parameters with smaller instrumental (systematic) errors in comparison with measurements performed in 512 channels or less. It also allows a more reliable fitting of complex Moessbauer spectra. In the present study the Moessbauer spectroscopy with the high velocity resolution was used for a comparative analysis of ferritin and its pharmaceutically important models as well as iron storage proteins in a chicken liver and a spleen. The ferritin, an iron storage protein, consists of a nanosized polynuclear iron core formed by a ferrihydrite surrounded by a protein shell. Iron-polysaccharide complexes contain {beta}-FeOOH iron cores coated with various polysaccharides. The Moessbauer spectra of the ferritin and commercial products Imferon, MaltoferR and Ferrum Lek as well as those of the chicken liver and spleen tissues were measured with the high velocity resolution at 295 and 90 K. They were fitted using two models: (1) with a homogeneous iron core (an approximation using one quadrupole doublet), and (2) with a heterogeneous iron core (an approximation using several quadrupole doublets). The model (1) can be used as the first approximation fit to visualize small variations in the hyperfine parameters. Using this model, differences in the Moessbauer hyperfine parameters were obtained in both 295 and 90 K Moessbauer spectra. However, this model was considered as a rough approximation because the measured Moessbauer spectra had non-Lorentzian line shapes. Therefore, the spectra of the ferritin, Imferon, MaltoferR and Ferrum Lek as well as those of the liver and spleen tissues were fitted again using the model (2) in which a different number of the quadrupole doublets was

  4. Iron oxide minerals in dust-source sediments from the Bodélé Depression, Chad: Implications for radiative properties and Fe bioavailability of dust plumes from the Sahara

    Science.gov (United States)

    Moskowitz, Bruce M; Reynolds, Richard L.; Goldstein, Harland L.; Beroquo, Thelma; Kokaly, Raymond F.; Bristow, Charlie S

    2016-01-01

    Atmospheric mineral dust can influence climate and biogeochemical cycles. An important component of mineral dust is ferric oxide minerals (hematite and goethite) which have been shown to influence strongly the optical properties of dust plumes and thus affect the radiative forcing of global dust. Here we report on the iron mineralogy of dust-source samples from the Bodélé Depression (Chad, north-central Africa), which is estimated to be Earth’s most prolific dust producer and may be a key contributor to the global radiative budget of the atmosphere as well as to long-range nutrient transport to the Amazon Basin. By using a combination of magnetic property measurements, Mössbauer spectroscopy, reflectance spectroscopy, chemical analysis, and scanning electron microscopy, we document the abundance and relative amounts of goethite, hematite, and magnetite in dust-source samples from the Bodélé Depression. The partition between hematite and goethite is important to know to improve models for the radiative effects of ferric oxide minerals in mineral dust aerosols. The combination of methods shows (1) the dominance of goethite over hematite in the source sediments, (2) the abundance and occurrences of their nanosize components, and (3) the ubiquity of magnetite, albeit in small amounts. Dominant goethite and subordinate hematite together compose about 2% of yellow-reddish dust-source sediments from the Bodélé Depression and contribute strongly to diminution of reflectance in bulk samples. These observations imply that dust plumes from the Bodélé Depression that are derived from goethite-dominated sediments strongly absorb solar radiation. The presence of ubiquitous magnetite (0.002–0.57 wt%) is also noteworthy for its potentially higher solubility relative to ferric oxide and for its small sizes, including PM iron apportionment is estimated at about 33% in ferric oxide minerals, 1.4% in magnetite, and 65% in ferric silicates. Structural iron in clay

  5. Minerals Masquerading As Enzymes: Abiotic Oxidation Of Soil Organic Matter In An Iron-Rich Humid Tropical Forest Soil

    Science.gov (United States)

    Hall, S. J.; Silver, W. L.

    2010-12-01

    Oxidative reactions play an important role in decomposing soil organic matter fractions that resist hydrolytic degradation, and fundamentally affect the cycling of recalcitrant soil carbon across ecosystems. Microbial extracellular oxidative enzymes (e.g. lignin peroxidases and laccases) have been assumed to provide a dominant role in catalyzing soil organic matter oxidation, while other potential oxidative mechanisms remain poorly explored. Here, we show that abiotic reactions mediated by the oxidation of ferrous iron (Fe(II)) could explain high potential oxidation rates in humid tropical forest soils, which often contain high concentrations of Fe(II) and experience rapid redox fluctuations between anaerobic and aerobic conditions. These abiotic reactions could provide an additional mechanism to explain high rates of decomposition in these ecosystems, despite frequent oxygen deficits. We sampled humid tropical forest soils in Puerto Rico, USA from various topographic positions, ranging from well-drained ridges to riparian valleys that experience broad fluctuations in redox potential. We measured oxidative activity by adding the model humic compound L-DOPA to soil slurries, followed by colorimetric measurements of the supernatant solution over time. Dilute hydrogen peroxide was added to a subset of slurries to measure peroxidative activity. We found that oxidative and peroxidative activity correlated positively with soil Fe(II) concentrations, counter to prevailing theory that low redox potential should suppress oxidative enzymes. Boiling or autoclaving sub-samples of soil slurries to denature any enzymes present typically increased peroxidative activity and did not eliminate oxidative activity, further suggesting the importance of an abiotic mechanism. We found substantial differences in the oxidation products of the L-DOPA substrate generated by our soil slurries in comparison with oxidation products generated by a purified enzyme (mushroom tyrosinase

  6. Review of CO2 Reduction Technologies using Mineral Carbonation of Iron and Steel Making Slag in Malaysia

    Science.gov (United States)

    Norhana Selamat, Siti; Nor, Nik Hisyamudin Muhd; Rashid, Muhammad Hanif Abdul; Fauzi Ahmad, Mohd; Mohamad, Fariza; Ismail, Al Emran; Fahrul Hassan, Mohd; Turan, Faiz Mohd; Zain, Mohd Zamzuri Mohd; Abu Bakar, Elmi; Seiji, Yokoyama

    2017-10-01

    Climate change, greenhouse gas effect, and global warming is envisioning to turn more awful and more terrible by year. Since the leading cause of global warming is uncontrolled CO2 in atmosphere. The amount of unused steel slag is expected to increment later on, steel industries is one of the mechanical industries that contribute the CO2 emission. That because this businesses deliver carbon in light of powers reductant and substantial volume of steel. The changes of atmosphere these day is truly developing concern and that make steel creator are confronted with test of discovering methods for bringing down CO2 emission. Malaysia is working decidedly in the diminishment of CO2 gas. There are a few techniques in decreasing the amount of CO2 in the air as underlined by the Intergovernmental Panel of Climate Change (IPCC), an organization under the United Country however CCS is an extremely encouraging innovation to moderate CO2 emission in air. Mineral carbonation is another technique to store carbon dioxide permanently, long term stability and vast capacity.

  7. Metal-Organic Framework Derived Iron Sulfide-Carbon Core-Shell Nanorods as a Conversion-Type Battery Material

    DEFF Research Database (Denmark)

    Huang, Wei; Li, Shuo; Cao, Xianyi

    2017-01-01

    of a redox conversion-type lithium-ion battery, this composite material has demonstrated high lithium-ion storage capacity at 1148 mA h g-1 under the current rate of 500 mA g-1 for 170 cycles and an impressive rate-retention capability at 657 mA h g-1 with a current density of 2000 mA g-1. On the basis......We report the design and nanoengineering of carbon-film-coated iron sulfide nanorods (C@Fe7S8) as an advanced conversion-type lithium-ion storage material. The structural advantages of the iron-based metal-organic framework (MIL-88-Fe) as both a sacrificed template and a precursor are explored...

  8. Thermal Decomposition of Calcium Perchlorate/Iron-Mineral Mixtures: Implications of the Evolved Oxygen from the Rocknest Eolian Deposit in Gale Crater, Mars

    Science.gov (United States)

    Bruck, A. M.; Sutter, B.; Ming, D. W.; Mahaffy, P.

    2014-01-01

    A major oxygen release between 300 and 500 C was detected by the Mars Curiosity Rover Sample Analysis at Mars (SAM) instrument at the Rocknest eolian deposit. Thermal decomposition of perchlorate (ClO4-) salts in the Rocknest samples are a possible explanation for this evolved oxygen release. Releative to Na-, K-, Mg-, and Fe-perchlorate, the thermal decomposition of Ca-perchlorate in laboratory experiments released O2 in the temperature range (400-500degC) closest to the O2 release temperatures observed for the Rocknest material. Furthermore, calcium perchlorate could have been the source of Cl in the chlorinated-hydrocarbons species that were detected by SAM. Different components in the Martian soil could affect the decomposition temperature of calcium per-chlorate or another oxychlorine species. This interaction of the two components in the soil could result in O2 release temperatures consistent with those detected by SAM in the Rocknest materials. The decomposition temperatures of various alkali metal perchlorates are known to decrease in the presence of a catalyst. The objective of this work is to investigate catalytic interactions on calcium perchlorate from various iron-bearing minerals known to be present in the Rocknest material

  9. Alginate/nanohydroxyapatite scaffolds with designed core/shell structures fabricated by 3D plotting and in situ mineralization for bone tissue engineering.

    Science.gov (United States)

    Luo, Yongxiang; Lode, Anja; Wu, Chengtie; Chang, Jiang; Gelinsky, Michael

    2015-04-01

    Composite scaffolds, especially polymer/hydroxyapatite (HAP) composite scaffolds with predesigned structures, are promising materials for bone tissue engineering. Various methods including direct mixing of HAP powder with polymers or incubating polymer scaffolds in simulated body fluid for preparing polymer/HAP composite scaffolds are either uncontrolled or require long times of incubation. In this work, alginate/nano-HAP composite scaffolds with designed pore parameters and core/shell structures were fabricated using 3D plotting technique and in situ mineralization under mild conditions (at room temperature and without the use of any organic solvents). Light microscopy, scanning electron microscopy, microcomputer tomography, X-ray diffraction, and Fourier transform infrared spectroscopy were applied to characterize the fabricated scaffolds. Mechanical properties and protein delivery of the scaffolds were evaluated, as well as the cell response to the scaffolds by culturing human bone-marrow-derived mesenchymal stem cells (hBMSC). The obtained data indicate that this method is suitable to fabricate alginate/nano-HAP composite scaffolds with a layer of nano-HAP, coating the surface of the alginate strands homogeneously and completely. The surface mineralization enhanced the mechanical properties and improved the cell attachment and spreading, as well as supported sustaining protein release, compared to pure alginate scaffolds without nano-HAP shell layer. The results demonstrated that the method provides an interesting option for bone tissue engineering application.

  10. Emission of organic compounds from mould and core binders used for casting iron, aluminium and bronze in sand moulds

    DEFF Research Database (Denmark)

    Tiedje, Niels Skat; Crepaz, Rudolf; Eggert, Torben

    2010-01-01

    compositions were tested. A test method that provides uniform test conditions is described. The method can be used as general test method to analyse off gasses from binders. Moulds containing a standard size casting were produced and the amount and type of organic compounds resulting from thermal degradation...... of binders was monitored when cast iron, bronze and aluminium was poured in the moulds. Binder degradation was measured by collecting off gasses in a specially designed ventilation hood at a constant flow rate. Samples were taken from the ventilation system and analysed for hydrocarbons and CO content...

  11. MINERAL COMPOSITION OF COOKIES DEVELOPED WITH ALMOND OR PEANUT FLOURS SUPPLEMENTED WITH IRON COMPOSIÇÃO MINERAL DE BISCOITOS ELABORADOS A PARTIR DE FARINHAS DE AMÊNDOA OU AMENDOIM ADICIONADAS DE FERRO

    Directory of Open Access Journals (Sweden)

    Flavia Vilas Boas Wiecheteck Piekarski

    2009-03-01

    Full Text Available

    One of the most important steps in the improvement of food products quality, in the last 40 years, is represented by food fortification with minerals and essential vitamins, a way to correct a deficiency, to balance the nutritional profile or to restore nutrients lost in the processing. In this context, this work aimed at mineral determination in gluten-free almond or peanut cookies, to verify their potential as a source of essential nutrients. The quantification of iron, magnesium, calcium, copper, zinc, potassium and sodium was carried out via flame atomic absorption spectroscopy and phosphorus was quantified via UV-VIS-spectrophotometry. The data showed that the cookies developed with almond could be considered, for adults, a source of copper and iron and rich in phosphorus and that the ones elaborated with peanuts could be considered rich in phosphorous, magnesium and iron. Both cookies could be considered sources of copper, magnesium, phosphorous and iron, when values are directed to the consumption of children from 4 to 6 years old, showing nutritional potential to celiacs.

     

    KEY-WORDS: Celiac disease; cookies; minerals; iron.

  1. An integrated technique using zero-valent iron and UV/H2O2 sequential process for complete decolorization and mineralization of C.I. Acid Black 24 wastewater

    International Nuclear Information System (INIS)

    Chang, M.-C.; Shu, H.-Y.; Yu, H.-H.

    2006-01-01

    The zero-valent iron (ZVI) reduction succeeds for decolorization, while UV/H 2 O 2 oxidation process results into mineralization, so that this study proposed an integrated technique by reduction coupling with oxidation process in order to acquire simultaneously complete both decolorization and mineralization of C.I. Acid Black 24. From the experimental data, the zero-valent iron addition alone can decolorize the dye wastewater yet it demanded longer time than ZVI coupled with UV/H 2 O 2 processes (Red-Ox). Moreover, it resulted into only about 30% removal of the total organic carbon (TOC), which was capable to be effectively mineralized by UV/H 2 O 2 process. The proposed sequential ZVI-UV/H 2 O 2 integration system cannot only effectively remove color and TOC in AB 24 wastewater simultaneously but also save irradiation power and time demand. Furthermore, the decolorization rate constants were about 3.77-4.0 times magnitude comparing with that by UV/H 2 O 2 process alone

  2. Deep-Earth Equilibration between Molten Iron and Solid Silicates

    Science.gov (United States)

    Brennan, M.; Zurkowski, C. C.; Chidester, B.; Campbell, A.

    2017-12-01

    Elemental partitioning between iron-rich metals and silicate minerals influences the properties of Earth's deep interior, and is ultimately responsible for the nature of the core-mantle boundary. These interactions between molten iron and solid silicates were influential during planetary accretion, and persist today between the mantle and liquid outer core. Here we report the results of diamond anvil cell experiments at lower mantle conditions (40 GPa, >2500 K) aimed at examining systems containing a mixture of metals (iron or Fe-16Si alloy) and silicates (peridotite). The experiments were conducted at pressure-temperature conditions above the metallic liquidus but below the silicate solidus, and the recovered samples were analyzed by FIB/SEM with EDS to record the compositions of the coexisting phases. Each sample formed a three-phase equilibrium between bridgmanite, Fe-rich metallic melt, and an oxide. In one experiment, using pure Fe, the quenched metal contained 6 weight percent O, and the coexisting oxide was ferropericlase. The second experiment, using Fe-Si alloy, was highly reducing; its metal contained 10 wt% Si, and the coexisting mineral was stishovite. The distinct mineralogies of the two experiments derived from their different starting metals. These results imply that metallic composition is an important factor in determining the products of mixed phase iron-silicate reactions. The properties of deep-Earth interfaces such as the core-mantle boundary could be strongly affected by their metallic components.

  3. Mineral industry in Australia

    International Nuclear Information System (INIS)

    Parbo, S.A.

    1982-01-01

    The paper reviews the history and growth of the mineral industry in Australia and its significance to the nation's economic growth and overseas trade, particularly over the last twenty years during which time production of coal, iron ore, manganese and mineral sands has increased greatly and new discoveries of petroleum, bauxite and nickel have given rise to major new industries. Australia ranks fourteenths in the value of world trade and is among the world's largest exporters of alumina, iron ore, mineral sands, coal, lead, zinc and nickel. Some details of production, processing and exports of the major minerals are given. Comment is made on the policies and roles of the six State Governments and the Federal Government in respect of ownership and control of the mining, processing and exporting of both energy and non-energy minerals. (orig.) [de

  4. Iron transport and storage in the coccolithophore: Emiliania huxleyi.

    Science.gov (United States)

    Hartnett, Andrej; Böttger, Lars H; Matzanke, Berthold F; Carrano, Carl J

    2012-11-01

    Iron is an essential element for all living organisms due to its ubiquitous role in redox and other enzymes, especially in the context of respiration and photosynthesis. The iron uptake and storage systems of terrestrial/higher plants are now reasonably well understood with two basic strategies for iron uptake being distinguished: strategy I plants use a mechanism involving soil acidification and induction of Fe(III)-chelate reductase (ferrireductase) and Fe(II) transporter proteins while strategy II plants have evolved sophisticated systems based on high-affinity, iron specific, binding compounds called phytosiderophores. In contrast, there is little knowledge about the corresponding systems in marine plant-like lineages. Herein we report a study of the iron uptake and storage mechanisms in the coccolithophore Emiliania huxleyi. Short term radio-iron uptake studies indicate that iron is taken up by Emiliania in a time and concentration dependent manner consistent with an active transport process. Based on inhibitor studies it appears that iron is taken up directly as Fe(iii). However if a reductive step is involved the Fe(II) must not be accessible to the external environment. Upon long term exposure to (57)Fe we have been able, using a combination of Mössbauer and XAS spectroscopies, to identify a single metabolite which displays spectral features similar to the phosphorus-rich mineral core of bacterial and plant ferritins.

  5. PROGENITOR-EXPLOSION CONNECTION AND REMNANT BIRTH MASSES FOR NEUTRINO-DRIVEN SUPERNOVAE OF IRON-CORE PROGENITORS

    Energy Technology Data Exchange (ETDEWEB)

    Ugliano, Marcella; Janka, Hans-Thomas; Marek, Andreas [Max-Planck-Institut fuer Astrophysik, Karl-Schwarzschild-Str. 1, D-85748 Garching (Germany); Arcones, Almudena [Institut fuer Kernphysik, Technische Universitaet Darmstadt, Schlossgartenstr. 2, D-64289 Darmstadt (Germany)

    2012-09-20

    We perform hydrodynamic supernova (SN) simulations in spherical symmetry for over 100 single stars of solar metallicity to explore the progenitor-explosion and progenitor-remnant connections established by the neutrino-driven mechanism. We use an approximative treatment of neutrino transport and replace the high-density interior of the neutron star (NS) by an inner boundary condition based on an analytic proto-NS core-cooling model, whose free parameters are chosen such that explosion energy, nickel production, and energy release by the compact remnant of progenitors around 20 M{sub Sun} are compatible with SN 1987A. Thus, we are able to simulate the accretion phase, initiation of the explosion, subsequent neutrino-driven wind phase for 15-20 s, and the further evolution of the blast wave for hours to days until fallback is completed. Our results challenge long-standing paradigms. We find that remnant mass, launch time, and properties of the explosion depend strongly on the stellar structure and exhibit large variability even in narrow intervals of the progenitors' zero-age main-sequence mass. While all progenitors with masses below {approx}15 M{sub Sun} yield NSs, black hole (BH) as well as NS formation is possible for more massive stars, where partial loss of the hydrogen envelope leads to weak reverse shocks and weak fallback. Our NS baryonic masses of {approx}1.2-2.0 M{sub Sun} and BH masses >6 M{sub Sun} are compatible with a possible lack of low-mass BHs in the empirical distribution. Neutrino heating accounts for SN energies between some 10{sup 50} erg and {approx}2 Multiplication-Sign 10{sup 51} erg but can hardly explain more energetic explosions and nickel masses higher than 0.1-0.2 M{sub Sun }. These seem to require an alternative SN mechanism.

  6. Performance Improvement of a Magnetized Coaxial Plasma Gun by adopting Iron-core Bias Coil and New Pre-Ionization System

    Science.gov (United States)

    Edo, Takahiro; Asai, T.; Tanaka, F.; Yamada, S.; Hosozawa, A.; Gota, H.; Roche, T.; Allfrey, I.; Matsumoto, T.

    2017-10-01

    A magnetized coaxial plasma gun (MCPG) is a device used to generate a compact toroid (CT), which has a spheromak-like configuration. A typical MCPG consists of a set of axisymmetric cylindrical electrodes, bias coil, and gas-puff valves. In order to expand the CT operating range, the distributions of the bias magnetic field and neutral gas have been investigated. We have developed a new means of generating stuffing flux. By inserting an iron core into the bias coil, the magnetic field increases dramatically; even a small current of a few Amps produces a sufficient bias field. According to a simulation result, it was also suggested that the radial distribution of the bias field is easily controlled. The ejected CT and the target FRC are cooled by excess neutral gas that typical MCPGs require to initiate a breakdown; therefore, we have adopted a miniature gun as a new pre-ionization (PI) system. By introducing this PI system, the breakdown occurs at lower neutral gas density so that the amount of excess neutral gas can be reduced.

  7. Atomic scale study of vacancies in Earth's inner core: effect of pressure and chemistry

    Science.gov (United States)

    Ritterbex, S.; Tsuchiya, T.

    2017-12-01

    Seismic observations of the Earth's inner core [1] remain ambiguously related to mineral physics studies of the inner core stable crystalline iron phase [2,3,4,5]. This makes it difficult to clarify the role of plastic deformation as one of the primary candidates responsible for the observed seismic anisotropy of Earth's inner core. Nonetheless, atomic self-diffusion mechanisms provide a direct link between plastic deformation and the mechanical properties of Earth's inner core stable iron phase(s). Using first-principles density functional based calculation techniques, we have studied the conjugate effect of pressure and chemistry on vacancy diffusion in HCP-, BCC- and FCC-iron by taking into account potential light alloying elements as hydrogen, silicon and sulfur. Our results show that inner core pressure highly inhibits the rate of intrinsic self-diffusion by suppressing defect concentration rather than by effecting the mobility of the defects. Moreover, we found light elements to be able to affect metallic bonding which allows for extrinsic diffusion mechanisms in iron under inner core conditions. The latter clearly enables to enhance defect concentration and hence to enhance the rate of plastic deformation. This suggests that inner core chemistry affects the rheological properties (e.g.viscosity) of iron alloys which finally should match with seismic observations. references: [1] Deuss, A., 2014. Heterogeneity and Anisotropy of Earth's inner core. An. Rev. Earth Planet. Sci. 42, 103-126. [2] Anzellini, S., Dewaele, A., Mezouar, M., Loubeyre, P., Morard, G., 2013. Melting of iron at Earth's inner core boundary based on fast X-ray diffraction. Science 340, 464-466. [3] Godwal, B.K., Gonzales-Cataldo, F., Verma, A.K., Stixrude, L., Jeanloz, R., 2015. Stability of iron crystal structures at 0.3-1.5 TPa. [4] Vocadlo, L., 2007. Ab initio calculations of the elasticity of iron and iron alloys at inner core conditions: evidence for a partially molten inner core

  8. Noble gas and halogen constraints on fluid sources in iron oxide-copper-gold mineralization: Mantoverde and La Candelaria, Northern Chile

    Science.gov (United States)

    Marschik, Robert; Kendrick, Mark A.

    2015-03-01

    The noble gas (Ar, Kr, Xe) and halogen (Cl, Br, I) composition of fluid inclusions in hydrothermal quartz and calcite related to the hypogene iron oxide-copper-gold (IOCG) mineralization at Mantoverde and Candelaria, Chile, have been investigated to provide new insights of fluid and salinity sources in Andean IOCG deposits. A combination of mechanical extraction by crushing and thermal decrepitation methods was applied and collectively indicate that fluid inclusions with salinities ranging from 3.4 up to 64 wt% NaCl equivalent have molar Br/Cl and I/Cl ratios of between 0.5 × 10-3 and 3.0 × 10-3 and I/Cl of between 8 × 10-6 and 25 × 10-6 in the majority of samples, with maximum values of 5.2 × 10-3 obtained for Br/Cl and 64 × 10-6 for I/Cl in fluid inclusions within individual samples. The fluid inclusions have age-corrected 40Ar/36Ar ratios ranging from the atmospheric value of 296 up to 490 ± 45, indicating the presence of crustal- or mantle-derived excess 40Ar in the fluid inclusions of most samples. The fluid inclusions have 84Kr/36Ar and 130Xe/36Ar ratios intermediate of air and air-saturated water. However, 40Ar/36Ar is not correlated with either 84Kr/36Ar or 130Xe/36Ar, and the fluid inclusion 36Ar concentrations of 0.2-3.5 × 10-10 mol/g (calculated from measured Cl/36Ar and thermometric salinity measurements) extend below the seawater value of 0.34 × 10-10 mol/g, suggesting that contamination with modern air is a minor artifact. The range of fluid inclusion Br/Cl and I/Cl ratios overlap those previously documented for the mantle and magmatic-hydrothermal ore deposits, and the fluids' unusually low 36Ar concentration is consistent with the involvement of magmatic-hydrothermal fluids. Input of additional non-magmatic fluid components is suggested by the spread in Br/Cl and I/Cl to values characteristic of bittern brine sedimentary formation waters and near atmospheric 40Ar/36Ar. These data are compatible with mixing of magmatic-hydrothermal fluids

  9. CD/MCD/VTVH-MCD Studies of Escherichia coli Bacterioferritin Support a Binuclear Iron Cofactor Site.

    Science.gov (United States)

    Kwak, Yeonju; Schwartz, Jennifer K; Huang, Victor W; Boice, Emily; Kurtz, Donald M; Solomon, Edward I

    2015-12-01

    Ferritins and bacterioferritins (Bfrs) utilize a binuclear non-heme iron binding site to catalyze oxidation of Fe(II), leading to formation of an iron mineral core within a protein shell. Unlike ferritins, in which the diiron site binds Fe(II) as a substrate, which then autoxidizes and migrates to the mineral core, the diiron site in Bfr has a 2-His/4-carboxylate ligand set that is commonly found in diiron cofactor enzymes. Bfrs could, therefore, utilize the diiron site as a cofactor rather than for substrate iron binding. In this study, we applied circular dichroism (CD), magnetic CD (MCD), and variable-temperature, variable-field MCD (VTVH-MCD) spectroscopies to define the geometric and electronic structures of the biferrous active site in Escherichia coli Bfr. For these studies, we used an engineered M52L variant, which is known to eliminate binding of a heme cofactor but to have very minor effects on either iron oxidation or mineral core formation. We also examined an H46A/D50A/M52L Bfr variant, which additionally disrupts a previously observed mononuclear non-heme iron binding site inside the protein shell. The spectral analyses define a binuclear and an additional mononuclear ferrous site. The biferrous site shows two different five-coordinate centers. After O2 oxidation and re-reduction, only the mononuclear ferrous signal is eliminated. The retention of the biferrous but not the mononuclear ferrous site upon O2 cycling supports a mechanism in which the binuclear site acts as a cofactor for the O2 reaction, while the mononuclear site binds the substrate Fe(II) that, after its oxidation to Fe(III), migrates to the mineral core.

  10. Mineral industry statistics 1975

    Energy Technology Data Exchange (ETDEWEB)

    1978-01-01

    Production, consumption and marketing statistics are given for solid fuels (coal, peat), liquid fuels and gases (oil, natural gas), iron ore, bauxite and other minerals quarried in France, in 1975. Also accident statistics are included. Production statistics are presented of the Overseas Departments and territories (French Guiana, New Caledonia, New Hebrides). An account of modifications in the mining field in 1975 is given. Concessions, exploitation permits, and permits solely for prospecting for mineral products are discussed. (In French)

  11. Iron oxide minerals in dust-source sediments from the Bodélé Depression, Chad: Implications for radiative properties and Fe bioavailability of dust plumes from the Sahara

    Science.gov (United States)

    Moskowitz, Bruce M; Reynolds, Richard L.; Goldstein, Harland L.; Beroquo, Thelma; Kokaly, Raymond F.; Bristow, Charlie S

    2016-01-01

    Atmospheric mineral dust can influence climate and biogeochemical cycles. An important component of mineral dust is ferric oxide minerals (hematite and goethite) which have been shown to influence strongly the optical properties of dust plumes and thus affect the radiative forcing of global dust. Here we report on the iron mineralogy of dust-source samples from the Bodélé Depression (Chad, north-central Africa), which is estimated to be Earth’s most prolific dust producer and may be a key contributor to the global radiative budget of the atmosphere as well as to long-range nutrient transport to the Amazon Basin. By using a combination of magnetic property measurements, Mössbauer spectroscopy, reflectance spectroscopy, chemical analysis, and scanning electron microscopy, we document the abundance and relative amounts of goethite, hematite, and magnetite in dust-source samples from the Bodélé Depression. The partition between hematite and goethite is important to know to improve models for the radiative effects of ferric oxide minerals in mineral dust aerosols. The combination of methods shows (1) the dominance of goethite over hematite in the source sediments, (2) the abundance and occurrences of their nanosize components, and (3) the ubiquity of magnetite, albeit in small amounts. Dominant goethite and subordinate hematite together compose about 2% of yellow-reddish dust-source sediments from the Bodélé Depression and contribute strongly to diminution of reflectance in bulk samples. These observations imply that dust plumes from the Bodélé Depression that are derived from goethite-dominated sediments strongly absorb solar radiation. The presence of ubiquitous magnetite (0.002–0.57 wt%) is also noteworthy for its potentially higher solubility relative to ferric oxide and for its small sizes, including PM bioavailability to marine and terrestrial ecosystems.

  12. Spectroscopic Evidence of the Improvement of Reactive Iron Mineral Content in Red Soil by Long-Term Application of Swine Manure.

    Directory of Open Access Journals (Sweden)

    Chichao Huang

    Full Text Available Mineral elements in soil solutions are thought to be the precursor of the formation of reactive minerals, which play an important role in global carbon (C cycling. However, information regarding the regulation of mineral elements release in soil is scarce. Here, we examined the long-term (i.e., 23 yrs effects of fertilisation practices on Fe minerals in a red soil in Southern China. The results from chemical analysis and Fourier-transform infrared spectroscopy showed that long-term swine manure (M treatment released greater amounts of minerals into soil solutions than chemical fertilisers (NPK treatment, and Fe played a dominant role in the preservation of dissolved organic C. Furthermore, Fe K-edge X-ray absorption near-edge fine structure spectroscopy demonstrated that reactive Fe minerals were mainly composed of less crystalline ferrihydrite in the M-treated soil and more crystalline goethite in the NPK-treated soil. In conclusion, this study reported spectroscopic evidence of the improvement of reactive Femineral content in the M-treated soil colloids when compared to NPK-treated soil colloids.

  13. Mid-infrared and near-infrared spectroscopic study of selected magnesium carbonate minerals containing ferric iron-Implications for the geosequestration of greenhouse gases.

    Science.gov (United States)

    Frost, Ray L; Reddy, B Jagannadha; Bahfenne, Silmarilly; Graham, Jessica

    2009-04-01

    The proposal to remove greenhouse gases by pumping liquefied CO(2) several kilometres below the ground implies that many carbonate containing minerals will be formed. Among these minerals brugnatellite and coalingite are probable. Two ferric ion bearing minerals brugnatellite and coalingite with a hydrotalcite-like structure have been characterised by a combination of infrared and near-infrared (NIR) spectroscopy. The infrared spectra of the OH stretching region are characterised by OH and water stretching vibrations. Both the first and second fundamental overtones of these bands are observed in the NIR spectra in the 7030-7235 cm(-1) and 10,490-10,570 cm(-1) regions. Intense (CO(3))(2-) symmetric and antisymmetric stretching vibrations support the concept that the carbonate ion is distorted. The position of the water bending vibration indicates the water is strongly hydrogen bonded in the mineral structure. Split NIR bands at around 8675 and 11,100 cm(-1) indicate that some replacement of magnesium ions by ferrous ions in the mineral structure has occurred. Near-infrared spectroscopy is ideal for the assessment of the formation of carbonate minerals.

  14. Modified composites based on mesostructured iron oxyhydroxide and synthetic minerals: a potential material for the treatment of various toxic heavy metals and its toxicity.

    Science.gov (United States)

    Chung, Seung-Gun; Ryu, Jae-Chun; Song, Mi-Kyung; An, Byungryul; Kim, Song-Bae; Lee, Sang-Hyup; Choi, Jae-Woo

    2014-02-28

    The composites of mesostructured iron oxyhydroxide and/or commercial synthetic zeolite were investigated for use in the removal of toxic heavy metals, such as cadmium, copper, lead and arsenic, from aqueous solution. Four types of adsorbents, dried alginate beads (DABs), synthetic-zeolite impregnated beads (SZIBs), meso-iron-oxyhydroxide impregnated beads (MIOIBs) and synthetic-zeolite/meso-iron-oxyhydroxide composite beads (SZMIOIBs), were prepared for heavy metal adsorption tests. Laboratory experiments were conducted to investigate the removal efficiencies of cations and anions of heavy metals and the possibility of regenerating the adsorbents. Among these adsorbents, the MIOIBs can simultaneously remove cations and anions of heavy metals; they have high adsorption capacities for lead (60.1mgg(-1)) and arsenic (71.9mgg(-1)) compared with other adsorbents, such as DABs (158.1 and 0.0mgg(-1)), SZIB (42.9 and 0.0mgg(-1)) and SZMIOIB (54.0 and 5.9mgg(-1)) for lead and arsenic, respectively. Additionally, the removal efficiency was consistent at approximately 90%, notwithstanding repetitive regeneration. The characteristics of meso-iron-oxyhydroxide powder were confirmed by X-ray diffraction, Brunauer-Emmett-Teller and transmission electron microscopy. We also performed a comparative toxicity study that indicated that much lower concentrations of the powdered form of mesostructured iron oxyhydroxide had stronger cytotoxicity than the granular form. These results suggest that the granular form of meso iron oxyhydroxide is a more useful and safer adsorbent for heavy metal treatment than the powdered form. This research provides promising results for the application of MIOIBs as an adsorbent for various heavy metals from wastewater and sewage. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. Iron-oxide Magnetic, Morphologic, and Compositional Tracers of Sediment Provenance and Ice Sheet Extent in the ANDRILL AND-1B Drill Core, Ross Sea, Antarctica (Invited)

    Science.gov (United States)

    Brachfeld, S. A.; Pinzon, J.; Darley, J. S.; Sagnotti, L.; Kuhn, G.; Florindo, F.; Wilson, G. S.; Ohneiser, C.; Monien, D.; Joseph, L. H.

    2013-12-01

    The first drilling season of the Antarctic Drilling Program (ANDRILL) recovered a 13.57 million year Miocene through Pleistocene record of paleoclimate change (core AND-1B) within the Ross Sea. The magnetic mineral assemblage records the varying contributions of biological productivity, changing sediment sources, the emergence of volcanic centers, and post-depositional diagenesis. Characterization of bedrock samples from the McMurdo Volcanic Group (MVG) and Transantarctic Mountain (TAM) lithologic units allows us to construct fingerprints for the major source rocks bordering the Ross Sea, and identify their signatures within the AND-1B sediment. Key parameters that can be traced from source rock to sediment for the MVG-derived sediment include a 100-200 C order-disorder transition, titanomaghemite grains with homogenous textures but with substantial Al and Mg content, Fe-spinels with substantial Al, Cr, Mg, and Ti content, and titanomagnetite host grains with 1-3 swarms of ilmenite lamellae (both with variable amounts of oxidation). Distinctive signatures in TAM lithologies include low S-ratios in Koettlitz Group gneisses and Fe-sulfides with magnetite intergrowths in Byrd Glacier basement samples. The Cambrian Granite Harbor Intrusive Complex is characterized by coarse, homogeneous Mn-bearing ilmenite and nearly pure magnetite. The Jurassic dolerites and basalts of the Ferrar Group contain pseudo single domain to stable single domain-sized Fe-oxides with low-Ti content and homogeneous textures. Cu-Fe sulfides are also present in the Ferrar Group. Diamictites in the Pliocene-Pleistocene section of the AND-1B drill core contains Fe-oxide assemblages with MVG-type rock magnetic and textural characteristics, while the Miocene diamictites contain TAM-type signatures. These observations can be explained by increased ice flow from the west during the Miocene and/or the absence of MVG volcanic centers, which had not yet reached a significant size. During the Pliocene and

  16. The palaeoenvironmental implications of carbonate petrography, kerogen distribution and carbon and oxygen isotope variations in the early Proterozoic transition from Campbellrand limestone to Kuruman iron-formation deposition in Griqualand West

    International Nuclear Information System (INIS)

    Beukes, N.J.; Klein, C.; Kaufman, A.J.; Hayes, J.M.

    1990-01-01

    The Griqualand West area of the Transvaal basin in South Africa offers a unique opportunity to study the relationships between the deposition of limestone and iron-formation. The stratigraphic sequence includes the transition from microbialaminated Campbellrand carbonates to the conformably Kuruman iron formation composed mainly of microbanded iron-formation. The relationships between carbonate mineral paragenesis, kerogen abundance, and isotopic compositions of carbon and oxygen for the same drill core samples are reported. The significance of whole rock carbon-isotopic compositions of iron-formations relative to those of limestones and dolomites are explored. 6 refs

  17. Modified composites based on mesostructured iron oxyhydroxide and synthetic minerals: A potential material for the treatment of various toxic heavy metals and its toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Seung-Gun [Center for Water Resource Cycle Research, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); Ryu, Jae-Chun; Song, Mi-Kyung [Center for Integrated Risk Research, Cellular and Molecular Toxicology Laboratory, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); An, Byungryul [Center for Water Resource Cycle Research, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); Kim, Song-Bae [Environmental Functional Materials and Biocolloids Laboratory, Seoul National University, Seoul 151-921 (Korea, Republic of); Lee, Sang-Hyup [Center for Water Resource Cycle Research, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); Graduate School of Convergence Green Technology and Policy, Korea University, Seoul 136-701 (Korea, Republic of); Choi, Jae-Woo, E-mail: plead36@kist.re.kr [Center for Water Resource Cycle Research, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136-791 (Korea, Republic of)

    2014-02-01

    Graphical abstract: - Highlights: • Meso-iron-oxyhydroxide was found to be efficient for anion heavy metal adsorption. • The composite bead can simultaneously remove the cations and anions of heavy metals. • Powdered form had stronger cytotoxicity than did the granular form. • Adsorbent recovery is facilitated by granulation process of powder-type. - Abstract: The composites of mesostructured iron oxyhydroxide and/or commercial synthetic zeolite were investigated for use in the removal of toxic heavy metals, such as cadmium, copper, lead and arsenic, from aqueous solution. Four types of adsorbents, dried alginate beads (DABs), synthetic-zeolite impregnated beads (SZIBs), meso-iron-oxyhydroxide impregnated beads (MIOIBs) and synthetic-zeolite/meso-iron-oxyhydroxide composite beads (SZMIOIBs), were prepared for heavy metal adsorption tests. Laboratory experiments were conducted to investigate the removal efficiencies of cations and anions of heavy metals and the possibility of regenerating the adsorbents. Among these adsorbents, the MIOIBs can simultaneously remove cations and anions of heavy metals; they have high adsorption capacities for lead (60.1 mg g{sup −1}) and arsenic (71.9 mg g{sup −1}) compared with other adsorbents, such as DABs (158.1 and 0.0 mg g{sup −1}), SZIB (42.9 and 0.0 mg g{sup −1}) and SZMIOIB (54.0 and 5.9 mg g{sup −1}) for lead and arsenic, respectively. Additionally, the removal efficiency was consistent at approximately 90%, notwithstanding repetitive regeneration. The characteristics of meso-iron-oxyhydroxide powder were confirmed by X-ray diffraction, Brunauer–Emmett–Teller and transmission electron microscopy. We also performed a comparative toxicity study that indicated that much lower concentrations of the powdered form of mesostructured iron oxyhydroxide had stronger cytotoxicity than the granular form. These results suggest that the granular form of meso iron oxyhydroxide is a more useful and safer adsorbent for

  18. Strata-bound Fe-Co-Cu-Au-Bi-Y-REE deposits of the Idaho Cobalt Belt: Multistage hydrothermal mineralization in a magmatic-related iron oxide copper-gold system

    Science.gov (United States)

    Slack, John F.

    2012-01-01

    Mineralogical and geochemical studies of strata-bound Fe-Co-Cu-Au-Bi-Y-rare-earth element (REE) deposits of the Idaho cobalt belt in east-central Idaho provide evidence of multistage epigenetic mineralization by magmatic-hydrothermal processes in an iron oxide copper-gold (IOCG) system. Deposits of the Idaho cobalt belt comprise three types: (1) strata-bound sulfide lenses in the Blackbird district, which are cobaltite and, less commonly, chalcopyrite rich with locally abundant gold, native bismuth, bismuthinite, xenotime, allanite, monazite, and the Be-rich silicate gadolinite-(Y), with sparse uraninite, stannite, and Bi tellurides, in a gangue of quartz, chlorite, biotite, muscovite, garnet, tourmaline, chloritoid, and/or siderite, with locally abundant fluorapatite or magnetite; (2) discordant tourmalinized breccias in the Blackbird district that in places have concentrations of cobaltite, chalcopyrite, gold, and xenotime; and (3) strata-bound magnetite-rich lenses in the Iron Creek area, which contain cobaltiferous pyrite and locally sparse chalcopyrite or xenotime. Most sulfide-rich deposits in the Blackbird district are enclosed by strata-bound lenses composed mainly of Cl-rich Fe biotite; some deposits have quartz-rich envelopes.Whole-rock analyses of 48 Co- and/or Cu-rich samples show high concentrations of Au (up to 26.8 ppm), Bi (up to 9.16 wt %), Y (up to 0.83 wt %), ∑REEs (up to 2.56 wt %), Ni (up to 6,780 ppm), and Be (up to 1,180 ppm), with locally elevated U (up to 124 ppm) and Sn (up to 133 ppm); Zn and Pb contents are uniformly low (≤821 and ≤61 ppm, respectively). Varimax factor analysis of bulk compositions of these samples reveals geochemically distinct element groupings that reflect statistical associations of monazite, allanite, and xenotime; biotite and gold; detrital minerals; chalcopyrite and sparse stannite; quartz; and cobaltite with sparse selenides and tellurides. Significantly, Cu is statistically separate from Co and As

  19. Banded Iron Formations

    DEFF Research Database (Denmark)

    Posth, Nicole R; Konhauser, Kurt O; Kappler, Andreas

    2011-01-01

    Sedimentary deposits of alternating iron-rich (20–40% Fe) and iron-poor, siliceous (40–50% SiO2) mineral layers that primarily precipitated throughout much of the late Archean (2.7–2.5 Ga) and Paleoproterozoic (2.5– 1.8 Ga), but then remerged in the Neoproterozoic (0.8 Ga).......Sedimentary deposits of alternating iron-rich (20–40% Fe) and iron-poor, siliceous (40–50% SiO2) mineral layers that primarily precipitated throughout much of the late Archean (2.7–2.5 Ga) and Paleoproterozoic (2.5– 1.8 Ga), but then remerged in the Neoproterozoic (0.8 Ga)....

  20. A deposit model for magmatic iron-titanium-oxide deposits related to Proterozoic massif anorthosite plutonic suites: Chapter K in Mineral Deposit Models for Resource Assessment

    Science.gov (United States)

    Woodruff, Laurel G.; Nicholson, Suzanne W.; Fey, David L.

    2013-01-01

    This descriptive model for magmatic iron-titanium-oxide (Fe-Ti-oxide) deposits hosted by Proterozoic age massif-type anorthosite and related rock types presents their geological, mineralogical, geochemical, and geoenvironmental attributes. Although these Proterozoic rocks are found worldwide, the majority of known deposits are found within exposed rocks of the Grenville Province, stretching from southwestern United States through eastern Canada; its extension into Norway is termed the Rogaland Anorthosite Province. This type of Fe-Ti-oxide deposit dominated by ilmenite rarely contains more than 300 million tons of ore, with between 10- to 45-percent titanium dioxide (TiO2), 32- to 45-percent iron oxide (FeO), and less than 0.2-percent vanadium (V).

  1. 40Ar-39Ar dating of Archean iron oxide Cu-Au and Paleoproterozoic granite-related Cu-Au deposits in the Carajás Mineral Province, Brazil: implications for genetic models

    Science.gov (United States)

    Pollard, Peter J.; Taylor, Roger G.; Peters, Lisa; Matos, Fernando; Freitas, Cantidiano; Saboia, Lineu; Huhn, Sergio

    2018-05-01

    this time. The Paleoproterozoic Cu-Au deposits are commonly hosted within Neoarchean IOCG alteration systems and the common occurrence of potassic alteration (especially biotite) in both types of deposits means that special care is required in interpreting the paragenesis of alteration in both types of deposits. The Paleoproterozoic Cu-Au deposits are reduced, and sulfur- and quartz-rich deposits lacking in major amounts of iron oxides and are therefore unlike IOCG deposits. Instead, they share many characteristics in common with widespread Paleoproterozoic Sn-W deposits in the Amazon Craton, including close spatial and temporal relationships with reduced A-type B-Li-F granites, and the occurrence of greisen and quartz-rich vein/breccia systems within and above granite cupolas. The occurrence of sericitic alteration in the Paleoproterozoic Cu-Au deposits is not evidence for an upward transition to sericitic alteration in IOCG deposits in the Carajás Mineral Province.

  2. The need for iron ore and the environmental Kuznets curve. Spain; 0176 La necesidad del mineral de hierro y la curva de Kuznets ambiental. El caso espanol

    Energy Technology Data Exchange (ETDEWEB)

    Torre de Palacios, L. de la

    2011-07-01

    Firstly, the environmental position of Spain with regard to steel consumption is defined according to the Kuznets curve (EKC) hypothesis. It is essential to undertake a complete environmental assessment of Spanish iron-ore consumption, to study the different steelmaking processes at this moment, emphasising the contribution of the high electric arc furnace. The use of recycled scrap, together with lower CO{sub 2} emissions, have succeeded in establishing Spain in a good environmental situation. (Author) 30 refs.

  3. Ferrous Iron Oxidation under Varying pO2 Levels: The Effect of Fe(III)/Al(III) Oxide Minerals and Organic Matter.

    Science.gov (United States)

    Chen, Chunmei; Thompson, Aaron

    2018-01-16

    Abiotic Fe(II) oxidation by O 2 commonly occurs in the presence of mineral sorbents and organic matter (OM) in soils and sediments; however, this tertiary system has rarely been studied. Therefore, we examined the impacts of mineral surfaces (goethite and γ-Al 2 O 3 ) and organic matter [Suwannee River fulvic acid (SRFA)] on Fe(II) oxidation rates and the resulting Fe(III) (oxyhydr)oxides under 21 and 1% pO 2 at pH 6. We tracked Fe dynamics by adding 57 Fe(II) to 56 Fe-labeled goethite and γ-Al 2 O 3 and characterized the resulting solids using 57 Fe Mössbauer spectroscopy. We found Fe(II) oxidation was slower at low pO 2 and resulted in higher-crystallinity Fe(III) phases. Relative to oxidation of Fe(II) (aq) alone, both goethite and γ-Al 2 O 3 surfaces increased Fe(II) oxidation rates regardless of pO 2 levels, with goethite being the stronger catalyst. Goethite surfaces promoted the formation of crystalline goethite, while γ-Al 2 O 3 favored nano/small particle or disordered goethite and some lepidocrocite; oxidation of Fe(II) aq alone favored lepidocrocite. SRFA reduced oxidation rates in all treatments except the mineral-free systems at 21% pO 2 , and SRFA decreased Fe(III) phase crystallinity, facilitating low-crystalline ferrihydrite in the absence of mineral sorbents, low-crystalline lepidocrocite in the presence of γ-Al 2 O 3 , but either crystalline goethite or ferrihydrite when goethite was present. This work highlights that the oxidation rate, the types of mineral surfaces, and OM control Fe(III) precipitate composition.

  4. Hydrogen-bearing iron peroxide and the origin of ultralow-velocity zones

    Science.gov (United States)

    Liu, Jin; Hu, Qingyang; Young Kim, Duck; Wu, Zhongqing; Wang, Wenzhong; Xiao, Yuming; Chow, Paul; Meng, Yue; Prakapenka, Vitali B.; Mao, Ho-Kwang; Mao, Wendy L.

    2017-11-01

    Ultralow-velocity zones (ULVZs) at Earth’s core-mantle boundary region have important implications for the chemical composition and thermal structure of our planet, but their origin has long been debated. Hydrogen-bearing iron peroxide (FeO2Hx) in the pyrite-type crystal structure was recently found to be stable under the conditions of the lowermost mantle. Using high-pressure experiments and theoretical calculations, we find that iron peroxide with a varying amount of hydrogen has a high density and high Poisson ratio as well as extremely low sound velocities consistent with ULVZs. Here we also report a reaction between iron and water at 86 gigapascals and 2,200 kelvin that produces FeO2Hx. This would provide a mechanism for generating the observed volume occupied by ULVZs through the reaction of about one-tenth the mass of Earth’s ocean water in subducted hydrous minerals with the effectively unlimited reservoir of iron in Earth’s core. Unlike other candidates for the composition of ULVZs, FeO2Hx synthesized from the superoxidation of iron by water would not require an extra transportation mechanism to migrate to the core-mantle boundary. These dense FeO2Hx-rich domains would be expected to form directly in the core-mantle boundary region and their properties would provide an explanation for the many enigmatic seismic features that are observed in ULVZs.

  5. Analysis of the behavior of orthogonal-core-type push-pull parametric transformer with iron and copper losses. Tetsuson oyobi doson wo koryoshita chokko jishinkei push pull parametric hen prime atsuki no dosa kaiseki

    Energy Technology Data Exchange (ETDEWEB)

    Tajima, K; Anazawa, Y; Kaga, A [Akita University, Akita (Japan). Mining College; Ichinokura, O [Tohoku University, Sendai (Japan). Faculty of Engineering

    1991-04-30

    This paper reports on a precise numerical analysis of operating characteristics of the push-pull parametric transformer of orthogonal-core type (proposed by the authors in the preceding papers) made in consideration of both the iron loss of its magnetic core and the copper loss of its windings. A model of magnetic circuit in the core is presented, which involves magnetic reluctances representing saturation characteristics of the core and magnetic inductances representing effects produced by hysteresis. Use is made of the function that expresses the saturation characteristics by a twenty-first power series of magnetic flux, the coefficient of each term being determined by use of experimental data on a specified sample of the magnetic core. Furthermore, recourse is had to the circuit simulator SPICE in order to analyze the operating characteristics of the transformer. Comparing results of the present analysis with experimental results, the following are noted: first, both output voltages and currents of windings of the transformer under the condition of parametric oscillation are calculated with sufficient accuracy; second, the present analysis is capable of evaluating the conversion efficiency of electric power and input power factor of the transformer, and of providing more accurate values of both voltage and current in the case of the maximum output under loading conditions as compared with the analyses so far presented. 8 refs., 11 figs., 2 tabs.

  6. The Effect Of Local Coal And Smelting Sponge Iron On Iron Content Of Pig Iron

    Science.gov (United States)

    Oediyani, Soesaptri; Juwita Sari, Pramita; Hadi P, Djoko

    2018-03-01

    The new regulation on mineral resources was announced by Ministry of Energy and Mineral resources (ESDM) of Indonesia at 2014 which it called Permen ESDM No 1/2014. Therefore, this research was conducted to add the value of local iron ores by using smelting technology. The objective of the research is to produce pig iron that meet the requirement of the new regulation of mineral resources such as 90% Fe. First, iron ores and coal mixed together with lime as a flux, then smelted in a Electric Arc Furnace at 1800°C. The process variables are (1; 1.25; 1.5; 1.75; 2.0) and the composition of coal (0.8%, 1.6%, 3.0%). The type of coal that used in this research was bituminous coal from Kalimantan and also the iron ores from Kalimantan. The products of the smelting technology are Pig iron and slag. Both pig iron and slag then analyzed by SEM-EDS to measure the iron content. The result shows that the maximum iron content on pig iron is about 95.04% meanwhile the minimum iron content on slag is about 3.66%. This result achieved at 1.6% coal and 2.0.

  7. Microbial Beneficiation of Salem Iron Ore Using Penicillium purpurogenum

    Science.gov (United States)

    Mishra, M.; Pradhan, M.; Sukla, L. B.; Mishra, B. K.

    2011-02-01

    High alumina and silica content in the iron ore affects coke rate, reducibility, and productivity in a blast furnace. Iron ore is being beneficiated all around the world to meet the quality requirement of iron and steel industries. Choosing a beneficiation treatment depends on the nature of the gangue present and its association with the ore structure. The advanced physicochemical methods used for the beneficiation of iron ore are generally unfriendly to the environment. Biobeneficiation is considered to be ecofriendly, promising, and revolutionary solutions to these problems. A characterization study of Salem iron ore indicates that the major iron-bearing minerals are hematite, magnetite, and goethite. Samples on average contains (pct) Fe2O3-84.40, Fe (total)-59.02, Al2O3-7.18, and SiO2-7.53. Penicillium purpurogenum (MTCC 7356) was used for the experiment . It removed 35.22 pct alumina and 39.41 pct silica in 30 days in a shake flask at 10 pct pulp density, 308 K (35 °C), and 150 rpm. In a bioreactor experiment at 2 kg scale using the same organism, it removed 23.33 pct alumina and 30.54 pct silica in 30 days at 300 rpm agitation and 2 to 3 l/min aeration. Alumina and silica dissolution follow the shrinking core model for both shake flask and bioreactor experiments.

  8. Natural nanomaterials : reappraising the elusive structure of the nano-sized mineral ferrihydrite through X-Ray absorption spectroscopy at the iron K-edge

    OpenAIRE

    Figueiredo, M. Ondina; Silva, Teresa Pereira; Veiga, João Pedro

    2013-01-01

    Ferrihydrite is natural ferric oxyhydroxide occurring exclusively nanocrystalline. With ideal formula 5 Fe2 O3 . 9 H2 O, ferrihydrite is quite abundant in sediments, weathering crusts and mine wastes, being characteristic of red pre-soils formed by loose weathered rock plus mineral debris (regoliths) and commonly designated as “2-line” or “6-line” on the basis of the broadened maxima observed in the X-ray diffraction pattern. Synthetic nanocrystalline “6-line” ferrihydrite was...

  9. Mineral resource of the month: vermiculite

    Science.gov (United States)

    Tanner, Arnold O.

    2014-01-01

    Vermiculite comprises a group of hydrated, laminar magnesium-aluminum-iron silicate minerals resembling mica. They are secondary minerals, typically altered biotite, iron-rich phlogopite or other micas or clay-like minerals that are themselves sometimes alteration products of amphibole, chlorite, olivine and pyroxene. Vermiculite deposits are associated with volcanic ultramafic rocks rich in magnesium silicate minerals, and flakes of the mineral range in color from black to shades of brown and yellow. The crystal structure of vermiculite contains water molecules, a property that is critical to its processing for common uses.

  10. Iron oxides in acid mine drainage environments and their association with bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Ferris, F G; Tazaki, K; Fyfe, W S

    1989-01-20

    A variety of iron oxides were identified by X-ray diffraction in sediments receiving acid drainage from mine tailing and coal refuse impoundments. Small amounts of goethite and hematite were found in the sediment samples. However, the major iron oxide species was ferrihydrite which gave diffuse diffraction bands at angles corresponding to d2.5, 2.2 and 1.5 Angstrom. Main core line binding energies in Fe (2p) and O (1s) X-ray photoelectron spectra were consistent with the hydrous nature and predominance of ferrihydrite. Electron microscopy and energy-dispersive X-ray spectroscopy also showed that individual bacterial cells promoted the development of iron oxide mineralization. The bacterial associated iron oxides were similar to those in the bulk sediment samples, and exhibited structures conforming to the presence of chemisorbed sulfate or silicate anions. 23 refs., 3 figs.

  11. Comparison of high temperature, high frequency core loss and dynamic B-H loops of two 50 Ni-Fe crystalline alloys and an iron-based amorphous alloy

    International Nuclear Information System (INIS)

    Wieserman, W.R.; Schwarze, G.E.; Niedra, J.M.

    1994-01-01

    The availability of experimental data that characterizes the performance of soft magnetic materials for the combined conditions of high temperature and high frequency is almost non-existent. An experimental investigation was conducted over the temperature range of 23 to 300 C and frequency range of 1 to 50 kHz to determine the effects of temperature and frequency on the core loss and dynamic B-H loops of three different soft magnetic materials; an oriented-grain 50Ni-50Fe alloy, a nonoriented-grain 50Ni-50Fe alloy, and an iron-based amorphous material (Metglas 2605SC). A comparison of these materials show that the nonoriented-grain 50Ni-50Fe alloy tends to have either the lowest or next lowest core loss for all temperatures and frequencies investigated

  12. A new method based on low background instrumental neutron activation analysis for major, trace and ultra-trace element determination in atmospheric mineral dust from polar ice cores

    Energy Technology Data Exchange (ETDEWEB)

    Baccolo, Giovanni, E-mail: giovanni.baccolo@mib.infn.it [Graduate School in Polar Sciences, University of Siena, Via Laterina 8, 53100, Siena (Italy); Department of Environmental Sciences, University of Milano-Bicocca, P.zza della Scienza 1, 20126, Milano (Italy); INFN, Section of Milano-Bicocca, P.zza della Scienza 3, 20126, Milano (Italy); Clemenza, Massimiliano [INFN, Section of Milano-Bicocca, P.zza della Scienza 3, 20126, Milano (Italy); Department of Physics, University of Milano-Bicocca, P.zza della Scienza 3, 20126, Milano (Italy); Delmonte, Barbara [Department of Environmental Sciences, University of Milano-Bicocca, P.zza della Scienza 1, 20126, Milano (Italy); Maffezzoli, Niccolò [Centre for Ice and Climate, Niels Bohr Institute, Juliane Maries Vej, 30, 2100, Copenhagen (Denmark); Nastasi, Massimiliano; Previtali, Ezio [INFN, Section of Milano-Bicocca, P.zza della Scienza 3, 20126, Milano (Italy); Department of Physics, University of Milano-Bicocca, P.zza della Scienza 3, 20126, Milano (Italy); Prata, Michele; Salvini, Andrea [LENA, University of Pavia, Pavia (Italy); Maggi, Valter [Department of Environmental Sciences, University of Milano-Bicocca, P.zza della Scienza 1, 20126, Milano (Italy); INFN, Section of Milano-Bicocca, P.zza della Scienza 3, 20126, Milano (Italy)

    2016-05-30

    Dust found in polar ice core samples present extremely low concentrations, in addition the availability of such samples is usually strictly limited. For these reasons the chemical and physical analysis of polar ice cores is an analytical challenge. In this work a new method based on low background instrumental neutron activation analysis (LB-INAA) for the multi-elemental characterization of the insoluble fraction of dust from polar ice cores is presented. Thanks to an accurate selection of the most proper materials and procedures it was possible to reach unprecedented analytical performances, suitable for ice core analyses. The method was applied to Antarctic ice core samples. Five samples of atmospheric dust (μg size) from ice sections of the Antarctic Talos Dome ice core were prepared and analyzed. A set of 37 elements was quantified, spanning from all the major elements (Na, Mg, Al, Si, K, Ca, Ti, Mn and Fe) to trace ones, including 10 (La, Ce, Nd, Sm, Eu, Tb, Ho, Tm, Yb and Lu) of the 14 natural occurring lanthanides. The detection limits are in the range of 10{sup −13}–10{sup −6} g, improving previous results of 1–3 orders of magnitude depending on the element; uncertainties lies between 4% and 60%. - Highlights: • A new method based on neutron activation for the multi-elemental characterization of atmospheric dust entrapped in polar ice cores is proposed. • 37 elements were quantified in μg size dust samples with detection limits ranging from 10{sup −13} to 10{sup −6} g. • A low background approach and a clean analytical protocol improved INAA performances to unprecedented levels for multi-elemental analyses.

  13. Iron biomineralization by anaerobic neutrophilic iron-oxidizing bacteria

    DEFF Research Database (Denmark)

    Miot, Jennyfer; Benzerara, Karim; Morin, Guillaume

    2009-01-01

    Minerals formed by bio-oxidation of ferrous iron (Fe(II)) at neutral pH, their association with bacterial ultrastructures as well as their impact on the metabolism of iron-oxidizing bacteria remain poorly understood. Here, we investigated iron biomineralization by the anaerobic nitrate-dependent ......Minerals formed by bio-oxidation of ferrous iron (Fe(II)) at neutral pH, their association with bacterial ultrastructures as well as their impact on the metabolism of iron-oxidizing bacteria remain poorly understood. Here, we investigated iron biomineralization by the anaerobic nitrate...... precipitation in the periplasm (in a few tens of minutes), followed by the formation of surface-bound globules. Moreover, we frequently observed an asymmetric mineral thickening at the cell poles. In parallel, the evolution of iron oxidation was quantified by STXM: iron both contained in the bacteria...... and in the extracellular precipitates reached complete oxidation within 6 days. While a progressive oxidation of Fe in the bacteria and in the medium could be observed, spatial redox (oxido-reduction state) heterogeneities were detected at the cell poles and in the extracellular precipitates after 1 day. All...

  14. Australian mineral industry annual review. Preliminary summaries 1985

    Energy Technology Data Exchange (ETDEWEB)

    1986-01-01

    Salient statistics and a general industry overview are presented. Special attention is given to the following mineral commodities: aluminium, black coal, copper, fertiliser minerals, gemstones, gold, iron, lead, manganese, nickel, tin, titanium, tungsten, uranium, zinc and zirconium.

  15. Mineral facilities of Europe

    Science.gov (United States)

    Almanzar, Francisco; Baker, Michael S.; Elias, Nurudeen; Guzman, Eric

    2010-01-01

    This map displays over 1,700 records of mineral facilities within the countries of Europe and western Eurasia. Each record represents one commodity and one facility type at a single geographic location. Facility types include mines, oil and gas fields, and plants, such as refineries, smelters, and mills. Common commodities of interest include aluminum, cement, coal, copper, gold, iron and steel, lead, nickel, petroleum, salt, silver, and zinc. Records include attributes, such as commodity, country, location, company name, facility type and capacity (if applicable), and latitude and longitude geographical coordinates (in both degrees-minutes-seconds and decimal degrees). The data shown on this map and in table 1 were compiled from multiple sources, including (1) the most recently available data from the U.S. Geological Survey (USGS) Minerals Yearbook (Europe and Central Eurasia volume), (2) mineral statistics and information from the USGS Minerals Information Web site (http://minerals.usgs.gov/minerals/pubs/country/europe.html), and (3) data collected by the USGS minerals information country specialists from sources, such as statistical publications of individual countries, annual reports and press releases of operating companies, and trade journals. Data reflect the most recently published table of industry structure for each country at the time of this publication. Additional information is available from the country specialists listed in table 2.

  16. Systematic variations of 87Sr/56Sr ratios, Sr compositions, selected major-oxide concentrations, and mineral abundances in piston cores from the Red Sea

    International Nuclear Information System (INIS)

    Boger, P.D.; Boger, J.L.; Faure, G.

    1980-01-01

    A mixing model is presented which relates the concentrations of Sr to the 87 Sr/ 86 Sr ratios and concentrations of other elements contained in a mixture of two components. The model is applied to the measured 87 Sr/ 86 Sr ratios, Sr, CaO, Fe 2 O 3 and SiO 2 concentrations of the detrital fractions of sediment from three piston cores representing different depositional environments in the Red Sea. The sediment is shown to be a mixture of two components derived from old sialic rocks and young volcanic rocks of the surrounding land masses. One of the cores contained a third component which is identified as authigenic Fe 2 O 3 . Removal of this contaminant is shown to return the system to its original detrital constituents. (Auth.)

  17. Native iron

    DEFF Research Database (Denmark)

    Brooks, Charles Kent

    2015-01-01

    System, was reduced. The oxidized outer layers of the Earth have formed by two processes. Firstly, water is decomposed to oxygen and hydrogen by solar radiation in the upper parts of the atmosphere, the light hydrogen diffusing to space, leaving oxygen behind. Secondly, plants, over the course......, hematite, or FeO.Fe2O3, magnetite), with carbon in the form of coke. This is carried out in a blast furnace. Although the Earth's core consists of metallic iron, which may also be present in parts of the mantle, this is inaccessible to us, so we must make our own. In West Greenland, however, some almost......We live in an oxidized world: oxygen makes up 22 percent of the atmosphere and by reacting with organic matter produces most of our energy, including the energy our bodies use to function: breathe, think, move, etc. It has not always been thus. Originally the Earth, in common with most of the Solar...

  18. Minerals in thalassaemia major patients: An overview.

    Science.gov (United States)

    Ozturk, Zeynep; Genc, Gizem Esra; Gumuslu, Saadet

    2017-05-01

    Thalassaemia major (TM) is a hereditary blood disease characterised by reduced or absent production of beta globin chains. Erythrocyte transfusions are given to raise the haemoglobin level in patients with thalassaemia major. However, transfusions have been related to increased risk of iron overload and tissue damage related to excess iron. Both elevated oxidative stress due to iron overload and increased hemolysis lead to over utilisation of minerals required for antioxidant enzymes activities. Iron chelators have been used to prevent iron overload in thalassaemia major patients, but these chelators have the possibility of removing minerals from the body. Thalassaemia patients are more at risk for mineral deficiency because of increased oxidative stress and iron chelation therapies. Growth and maturational delay, cardiomyopathy, endocrinopathies and osteoporosis are the complications of thalassaemia. Minerals may play a particular role to prevent these complications. In the current review, we provide an overview of minerals including zinc (Zn), copper (Cu), selenium (Se), magnesium (Mg) and calcium (Ca) in thalassaemia major patients. We, also, underline that some complications of thalassaemia can be caused by an increased need for minerals or lack of the minerals. Copyright © 2017 Elsevier GmbH. All rights reserved.

  19. Reductive mineralization of cellulose with vanadium, iron and tungsten chlorides and access to MxOy metal oxides and MxOy/C metal oxide/carbon composites.

    Science.gov (United States)

    Henry, Aurélien; Hesemann, Peter; Alauzun, Johan G; Boury, Bruno

    2017-10-15

    M x O y and M x O y /C composites (M=V, Fe and W) were obtained by mineralization of cellulose with several metal chlorides. Cellulose was used both as a templating agent and as an oxygen and a carbon source. Soluble chloride molecules (VOCl 3 and WCl 6 ) and a poorly soluble ionic chloride compound (FeCl 3 ) were chosen as metal oxide precursors. In a first time, primary metal oxide/cellulose composites were obtained via a thermal treatment by reacting urea impregnated filter paper with the corresponding metal chlorides in an autoclave at 150°C after 3days. After either pyrolysis or calcination steps of these intermediate materials, interesting metal oxides with various morphologies were obtained (V 2 O 5, V 2 O 3 , Fe 3 O 4 , WO 3, H 0.23 WO 3 ), composites (V 2 O 3 /C) as well as carbides (hexagonal W 2 C and WC, Fe 3 C) This result highlight the reductive role that can play cellulose during the pyrolysis step that allows to tune the composition of M x O y /C composites. The materials were characterized by FTIR, Raman, TGA, XRD and SEM. This study highlights that cellulose can be used for a convenient preparation of a variety of highly demanded M x O y and M x O y /C composites with original shapes and morphologies. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Measurements of cross-section of charge current inclusive of antineutrino scattering off nucleons using carbon, iron, lead and scintillator at MINER$\

    Energy Technology Data Exchange (ETDEWEB)

    Rakotondravohitra, Laza [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

    2015-08-18

    Neutrino physics is one of the most active fields in the domaine of high energy physics during the last century. The need of precise measurement of neutrino-nucleus interactions required by the neutrino oscillation experiments is a an exiting step. These measurements of cross-section are more than essential for neutrino oscillation experiment. Over the year, many measurements from varieties of experiments have been presented. MINERνA is one of the world leaders in measuring cross-section of neutrino and antineutrino -nucleus interactions. MINERνA is a neutrino-nucleus scattering experiment installed in the few-GeV NuMI beam line at Fermilab. In order to study nuclear dependence, MINERνA is endowed with different types of solid nuclear targets as well are liquid targets such as helium and water. This thesis presents measurements of cross-section of antineutrino scattering off nucleons using a variety of solid nuclear targets, carbon, iron, lead and also polystyrene scintillator (CH). The data set of antineutrino used for this analysis was taken between March and July 2010 with a total of 1.60X1020 protons on target. Charged current inclusive interactions were selected by requiring a positive muon and kinematics limitation of acceptance of the muon spectrometer are applied. The analysis requires neutrino energy between 2GeV et 20GeV and the angle of muon θmu < 17degree . The absolute cross-section # as function of neutrino energy and the differential cross-section dσ/ dxbj measured and shown the corresponding systematics for each nuclear targets. Data results are compared with prediction of the models implemented in the neutrino events generators GENIE 2.6.2 used by the experiment.

  1. Normal Mode Derived Models of the Physical Properties of Earth's Outer Core

    Science.gov (United States)

    Irving, J. C. E.; Cottaar, S.; Lekic, V.; Wu, W.

    2017-12-01

    Earth's outer core, the largest reservoir of metal in our planet, is comprised of an iron alloy of an uncertain composition. Its dynamical behaviour is responsible for the generation of Earth's magnetic field, with convection driven both by thermal and chemical buoyancy fluxes. Existing models of the seismic velocity and density of the outer core exhibit some variation, and there are only a small number of models which aim to represent the outer core's density.It is therefore important that we develop a better understanding of the physical properties of the outer core. Though most of the outer core is likely to be well mixed, it is possible that the uppermost outer core is stably stratified: it may be enriched in light elements released during the growth of the solid, iron enriched, inner core; by elements dissolved from the mantle into the outer core; or by exsolution of compounds previously dissolved in the liquid metal which will eventually be swept into the mantle. The stratified layer may host MAC or Rossby waves and it could impede communication between the chemically differentiated mantle and outer core, including screening out some of the geodynamo's signal. We use normal mode center frequencies to estimate the physical properties of the outer core in a Bayesian framework. We estimate the mineral physical parameters needed to best produce velocity and density models of the outer core which are consistent with the normal mode observations. We require that our models satisfy realistic physical constraints. We create models of the outer core with and without a distinct uppermost layer and assess the importance of this region.Our normal mode-derived models are compared with observations of body waves which travel through the outer core. In particular, we consider SmKS waves which are especially sensitive to the uppermost outer core and are therefore an important way to understand the robustness of our models.

  2. A volatile-rich Earth's core inferred from melting temperature of core materials

    Science.gov (United States)

    Morard, G.; Andrault, D.; Antonangeli, D.; Nakajima, Y.; Auzende, A. L.; Boulard, E.; Clark, A. N.; Lord, O. T.; Cervera, S.; Siebert, J.; Garbarino, G.; Svitlyk, V.; Mezouar, M.

    2016-12-01

    Planetary cores are mainly constituted of iron and nickel, alloyed with lighter elements (Si, O, C, S or H). Understanding how these elements affect the physical and chemical properties of solid and liquid iron provides stringent constraints on the composition of the Earth's core. In particular, melting curves of iron alloys are key parameter to establish the temperature profile in the Earth's core, and to asses the potential occurrence of partial melting at the Core-Mantle Boundary. Core formation models based on metal-silicate equilibration suggest that Si and O are the major light element components1-4, while the abundance of other elements such as S, C and H is constrained by arguments based on their volatility during planetary accretion5,6. Each compositional model implies a specific thermal state for the core, due to the different effect that light elements have on the melting behaviour of Fe. We recently measured melting temperatures in Fe-C and Fe-O systems at high pressures, which complete the data sets available both for pure Fe7 and other binary alloys8. Compositional models with an O- and Si-rich outer core are suggested to be compatible with seismological constraints on density and sound velocity9. However, their crystallization temperatures of 3650-4050 K at the CMB pressure of 136 GPa are very close to, if not higher than the melting temperature of the silicate mantle and yet mantle melting above the CMB is not a ubiquitous feature. This observation requires significant amounts of volatile elements (S, C or H) in the outer core to further reduce the crystallisation temperature of the core alloy below that of the lower mantle. References 1. Wood, B. J., et al Nature 441, 825-833 (2006). 2. Siebert, J., et al Science 339, 1194-7 (2013). 3. Corgne, A., et al Earth Planet. Sc. Lett. 288, 108-114 (2009). 4. Fischer, R. a. et al. Geochim. Cosmochim. Acta 167, 177-194 (2015). 5. Dreibus, G. & Palme, H. Geochim. Cosmochim. Acta 60, 1125-1130 (1995). 6. Mc

  3. Erythrogram, oxidative stress and mineral interaction in naturally infected lambs supplemented with different forms of oral ironEritrograma, estresse oxidativo e interação mineral em cordeiros naturalmente infectados por parasitas gastrintestinais suplementados com diferentes formas de ferro oral

    Directory of Open Access Journals (Sweden)

    Marta Lizandra Rêgo Leal

    2012-05-01

    Full Text Available The present study aimed to assess the oxidative profile, erythrogram and mineral interaction in lambs with anemia due to worm infection supplemented with different forms of oral iron. It was used 27 lambs, 6 to 8 month old, naturally infected by Haemonchus contortus, which showed packed cell volume between 16 and 18%. The animals were divided in three groups: Control Group (GC n=9, Ferrous Sulphate Group (G2 n=9 and Ferric Sulphate Group (G3 n=9. The animals of G2 received 1 g of ferrous sulphate (Fe+2 orally daily, equivalent to 200 milligram of iron, the animals of G3 received 1 g of ferric sulphate (Fe+3 orally daily, or equivalent to 200 milligram of iron, whereas the GC received no treatment. The samples were taked on day 0, 7, 14, 21 and 28 of the experiment, and during four days two animals of each group were kept in metabolic cages to measure the faecal minerals excretion. There was no difference among the groups about serum iron values and parameters of red blood cells. The serum copper and zinc values were lower in the G2 and G3 on days 21 and 28 of the experiment, whereas the faecal copper, iron and zinc excretion was higher in the same groups. The superoxide dismutase (SOD levels were lower in the G2 and G3 on day 28 whereas the levels of non-protein thiol groups (NPTH showed a decrease on days 21 and 28. In relation to reactive species thio-barbituric acid (TBARS, there was an increase on day 28 in the G2 and G3. Based on these results, it was concluded that the oral supplementation with 200 mg of iron, irrespective of its form, ferrous or ferric, does not increase the erythrocyte response in lambs. As well as, it has antagonist action on copper and zinc, reducing its serum concentrations and increasing the faecal excretion of these minerals. Moreover, the decrease of the serum copper and zinc concentrations causes a decrease in activity of superoxide dismutase, causing an oxidative stress situation.O presente estudo teve por

  4. Rb-Sr systematics in drill core samples of the Eye-Dashwa Lakes pluton at the whole rock and mineral scale

    International Nuclear Information System (INIS)

    Peterman, Z.E.; Futa, K.; Kamineni, D.C.

    1990-01-01

    Twenty-one whole-rock samples from boreholes ATK-1 and ATK-6 define a precise Rb-Sr isochron with an age of 2637 ± 33 Ma and initial 87 Sr/ 86 Sr intercept, IR(Sr), of 0.70144 ± 0.00006. An internal mineral isochron for ATC-1 (991-997) and biotites from ATK-1 (35.63) and ATK-1 (3.84) give younger ages of 2541 ± 14 Ma 2574 ± 25 Ma, and 2534 ± 25 Ma, respectively. Data for samples from fracture zones scatter but correlate around an isochron of 2281 ± 153 Ma. The internal isochron and biotite ages record cooling below about 300 C due to uplift and erosion. The younger age, 2281 ± 153 Ma, records an episode or episodes of brittle failure at relatively high crustal levels. These fractures provided pathways for infiltration of water, which facilitated the mineralogical alteration

  5. Potentiometric assessment of iron release during ferritin reduction by exogenous agents.

    Science.gov (United States)

    Vladimirova, Lilia S; Kochev, Valery K

    2010-09-01

    This work studied the possibilities for quantitative determination of iron mobilization in connection with ferritin reduction by ascorbic acid (vitamin C) and sodium dithionite in vitro. The iron storage protein was incubated with an excess of reductant in aerobic conditions in the absence of complexing agents in the medium. The release of Fe(2+) was let to go to completion, and the overall content of Fe(2+) in the solution was evaluated with the aid of potentiometric titration using Ce(4+) as an oxidizing titrant. Results suggest a moderate iron efflux under the influence of the chosen reducing agents. Although such a reduction of the protein mineral core by dihydroxyfumarate contributes greatly to the iron mobilization, ferritin behavior with vitamin C and dithionite seems to be different. Although redox properties of dihydroxyfumarate are determined by hydroxyl groups similar to those of ascorbic acid, the two compounds differ significantly in structure, and this could be the basis for an explanation of the specificities in their interaction with ferritin. As revealed by the study, potentiometric titration promises to be a reliable tool for evaluation of the amount of Fe(2+) present in the solution as a result of the reduction of the ferritin's mineral core. 2010 Elsevier Inc. All rights reserved.

  6. Mineral Dissolution and Precipitation due to Carbon Dioxide-Water-Rock Interactions: The Significance of Accessory Minerals in Carbonate Reservoirs (Invited)

    Science.gov (United States)

    Kaszuba, J. P.; Marcon, V.; Chopping, C.

    2013-12-01

    Accessory minerals in carbonate reservoirs, and in the caprocks that seal these reservoirs, can provide insight into multiphase fluid (CO2 + H2O)-rock interactions and the behavior of CO2 that resides in these water-rock systems. Our program integrates field data, hydrothermal experiments, and geochemical modeling to evaluate CO2-water-rock reactions and processes in a variety of carbonate reservoirs in the Rocky Mountain region of the US. These studies provide insights into a wide range of geologic environments, including natural CO2 reservoirs, geologic carbon sequestration, engineered geothermal systems, enhanced oil and gas recovery, and unconventional hydrocarbon resources. One suite of experiments evaluates the Madison Limestone on the Moxa Arch, Southwest Wyoming, a sulfur-rich natural CO2 reservoir. Mineral textures and geochemical features developed in the experiments suggest that carbonate minerals which constitute the natural reservoir will initially dissolve in response to emplacement of CO2. Euhedral, bladed anhydrite concomitantly precipitates in response to injected CO2. Analogous anhydrite is observed in drill core, suggesting that secondary anhydrite in the natural reservoir may be related to emplacement of CO2 into the Madison Limestone. Carbonate minerals ultimately re-precipitate, and anhydrite dissolves, as the rock buffers the acidity and reasserts geochemical control. Another suite of experiments emulates injection of CO2 for enhanced oil recovery in the Desert Creek Limestone (Paradox Formation), Paradox Basin, Southeast Utah. Euhedral iron oxyhydroxides (hematite) precipitate at pH 4.5 to 5 and low Eh (approximately -0.1 V) as a consequence of water-rock reaction. Injection of CO2 decreases pH to approximately 3.5 and increases Eh by approximately 0.1 V, yielding secondary mineralization of euhedral pyrite instead of iron oxyhydroxides. Carbonate minerals also dissolve and ultimately re-precipitate, as determined by experiments in the

  7. Spectroscopic characterization of manganese minerals.

    Science.gov (United States)

    Lakshmi Reddy, S; Padma Suvarna, K; Udayabhaska Reddy, G; Endo, Tamio; Frost, R L

    2014-01-03

    Manganese minerals ardenite, alleghanyite and leucopoenicite originated from Madhya Pradesh, India, Nagano prefecture Japan, Sussex Country and Parker Shaft Franklin, Sussex Country, New Jersey respectively are used in the present work. In these minerals manganese is the major constituent and iron if present is in traces only. An EPR study of on all of the above samples confirms the presence of Mn(II) with g around 2.0. Optical absorption spectrum of the mineral alleghanyite indicates that Mn(II) is present in two different octahedral sites and in leucophoenicite Mn(II) is also in octahedral geometry. Ardenite mineral gives only a few Mn(II) bands. NIR results of the minerals ardenite, leucophoenicite and alleghanyite are due to hydroxyl and silicate anions which confirming the formulae of the minerals. Copyright © 2013 Elsevier B.V. All rights reserved.

  8. Oxygen Extraction from Minerals

    Science.gov (United States)

    Muscatello, Tony

    2017-01-01

    Oxygen, whether used as part of rocket bipropellant or for astronaut life support, is a key consumable for space exploration and commercialization. In Situ Resource Utilization (ISRU) has been proposed many times as a method for making space exploration more cost effective and sustainable. On planetary and asteroid surfaces the presence of minerals in the regolith that contain oxygen is very common, making them a potential oxygen resource. The majority of research and development for oxygen extraction from minerals has been for lunar regolith although this work would generally be applicable to regolith at other locations in space. This presentation will briefly survey the major methods investigated for oxygen extraction from regolith with a focus on the current status of those methods and possible future development pathways. The major oxygen production methods are (1) extraction from lunar ilmenite (FeTiO3) with either hydrogen or carbon monoxide, (2) carbothermal reduction of iron oxides and silicates with methane, and (3) molten regolith electrolysis (MRE) of silicates. Methods (1) and (2) have also been investigated in a two-step process using CO reduction and carbon deposition followed by carbothermal reduction. All three processes have byproducts that could also be used as resources. Hydrogen or carbon monoxide reduction produce iron metal in small amounts that could potentially be used as construction material. Carbothermal reduction also makes iron metal along with silicon metal and a glass with possible applications. MRE produces iron, silicon, aluminum, titanium, and glass, with higher silicon yields than carbothermal reduction. On Mars and possibly on some moons and asteroids, water is present in the form of mineral hydrates, hydroxyl (-OH) groups on minerals, andor water adsorbed on mineral surfaces. Heating of the minerals can liberate the water which can be electrolyzed to provide a source of oxygen as well. The chemistry of these processes, some key

  9. First combined total reflection X-ray fluorescence and grazing incidence X-ray absorption spectroscopy characterization of aeolian dust archived in Antarctica and Alpine deep ice cores

    Energy Technology Data Exchange (ETDEWEB)

    Cibin, G. [Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxon OX110DE (United Kingdom); IMONT/EIM, Ente Italiano della Montagna, P.za dei Caprettari 70, 00176 Roma (Italy); Universita' degli Studi di Roma Tre, Dipartimento di Scienze Geologiche, L.go S. Leonardo Murialdo 1, 00146 Roma (Italy)], E-mail: giannantonio.cibin@diamond.ac.uk; Marcelli, A. [INFN - Laboratori Nazionali di Frascati, P.O. Box 13, 00044 Frascati (Roma) (Italy); Maggi, V. [Universita degli Studi di Milano-Bicocca, Dipartimento di Scienze dell' Ambiente e del Territorio, Piazza della Scienza 1, 20126 Milano (Italy); Sala, M. [Universita degli Studi di Milano-Bicocca, Dipartimento di Scienze dell' Ambiente e del Territorio, Piazza della Scienza 1, 20126 Milano (Italy); Universita degli Studi di Milano, Dipartimento di Scienze della Terra ' A. Desio' , Sez. Mineralogia, Via Mangiagalli 34, 20133 Milano (Italy); Marino, F.; Delmonte, B. [Universita degli Studi di Milano-Bicocca, Dipartimento di Scienze dell' Ambiente e del Territorio, Piazza della Scienza 1, 20126 Milano (Italy); Albani, S. [Universita degli Studi di Milano-Bicocca, Dipartimento di Scienze dell' Ambiente e del Territorio, Piazza della Scienza 1, 20126 Milano (Italy); Universita degli Studi di Siena, Dottorato in Scienze Polari, via Laterina 8, 53100 Siena (Italy); Pignotti, S. [IMONT/EIM, Ente Italiano della Montagna, P.za dei Caprettari 70, 00176 Roma (Italy)

    2008-12-15

    Aeolian mineral dust archived in polar and mid latitude ice cores represents a precious proxy for assessing environmental and climatic variations at different timescales. In this respect, the identification of dust mineralogy plays a key role. In this work we performed the first preliminary X-ray absorption spectroscopy (XAS) experiments on mineral dust particles extracted from Antarctic and from Alpine firn cores using grazing incidence geometry at the Fe K-edge. A dedicated high vacuum experimental chamber was set up for normal-incidence and total-reflection X-Ray Fluorescence and Absorption Spectroscopy analyses on minor amounts of mineral materials at the Stanford Synchrotron Radiation Laboratory. Results show that this experimental technique and protocol allows recognizing iron inclusion mineral fraction on insoluble dust in the 1-10 {mu}g range.

  10. First combined total reflection X-ray fluorescence and grazing incidence X-ray absorption spectroscopy characterization of aeolian dust archived in Antarctica and Alpine deep ice cores

    International Nuclear Information System (INIS)

    Cibin, G.; Marcelli, A.; Maggi, V.; Sala, M.; Marino, F.; Delmonte, B.; Albani, S.; Pignotti, S.

    2008-01-01

    Aeolian mineral dust archived in polar and mid latitude ice cores represents a precious proxy for assessing environmental and climatic variations at different timescales. In this respect, the identification of dust mineralogy plays a key role. In this work we performed the first preliminary X-ray absorption spectroscopy (XAS) experiments on mineral dust particles extracted from Antarctic and from Alpine firn cores using grazing incidence geometry at the Fe K-edge. A dedicated high vacuum experimental chamber was set up for normal-incidence and total-reflection X-Ray Fluorescence and Absorption Spectroscopy analyses on minor amounts of mineral materials at the Stanford Synchrotron Radiation Laboratory. Results show that this experimental technique and protocol allows recognizing iron inclusion mineral fraction on insoluble dust in the 1-10 μg range

  11. Biofilm formation and potential for iron cycling in serpentinization-influenced groundwater of the Zambales and Coast Range ophiolites.

    Science.gov (United States)

    Meyer-Dombard, D'Arcy R; Casar, Caitlin P; Simon, Alexander G; Cardace, Dawn; Schrenk, Matthew O; Arcilla, Carlo A

    2018-05-01

    Terrestrial serpentinizing systems harbor microbial subsurface life. Passive or active microbially mediated iron transformations at alkaline conditions in deep biosphere serpentinizing ecosystems are understudied. We explore these processes in the Zambales (Philippines) and Coast Range (CA, USA) ophiolites, and associated surface ecosystems by probing the relevance of samples acquired at the surface to in situ, subsurface ecosystems, and the nature of microbe-mineral associations in the subsurface. In this pilot study, we use microcosm experiments and batch culturing directed at iron redox transformations to confirm thermodynamically based predictions that iron transformations may be important in subsurface serpentinizing ecosystems. Biofilms formed on rock cores from the Zambales ophiolite on surface and in-pit associations, confirming that organisms from serpentinizing systems can form biofilms in subsurface environments. Analysis by XPS and FTIR confirmed that enrichment culturing utilizing ferric iron growth substrates produced reduced, magnetic solids containing siderite, spinels, and FeO minerals. Microcosms and enrichment cultures supported organisms whose near relatives participate in iron redox transformations. Further, a potential 'principal' microbial community common to solid samples in serpentinizing systems was identified. These results indicate collectively that iron redox transformations should be more thoroughly and universally considered when assessing the function of terrestrial subsurface ecosystems driven by serpentinization.

  12. Economical characteristics of base types of minerals. 1. Metallic minerals

    International Nuclear Information System (INIS)

    Khasanov, A.Kh.

    1990-01-01

    Metallic minerals is raw materials base of black and colour metallurgy. In this article of book author describes the group of black metals (iron, manganese, chromium), group of tempers (titanium, vanadium, nickel, cobalt, molybdenum, tungsten), colour metals (copper, lead, zinc, aluminium, tin, mercury, antimony, bismuth) and etc.

  13. Visible-near infrared point spectrometry of drill core samples from Río Tinto, Spain: results from the 2005 Mars Astrobiology Research and Technology Experiment (MARTE) drilling exercise.

    Science.gov (United States)

    Sutter, Brad; Brown, Adrian J; Stoker, Carol R

    2008-10-01

    Sampling of subsurface rock may be required to detect evidence of past biological activity on Mars. The Mars Astrobiology Research and Technology Experiment (MARTE) utilized the Río Tinto region, Spain, as a Mars analog site to test dry drilling technologies specific to Mars that retrieve subsurface rock for biological analysis. This work examines the usefulness of visible-near infrared (VNIR) (450-1000 nm) point spectrometry to characterize ferric iron minerals in core material retrieved during a simulated Mars drilling mission. VNIR spectrometry can indicate the presence of aqueously precipitated ferric iron minerals and, thus, determine whether biological analysis of retrieved rock is warranted. Core spectra obtained during the mission with T1 (893-897 nm) and T2 (644-652 nm) features indicate goethite-dominated samples, while relatively lower wavelength T1 (832-880 nm) features indicate hematite. Hematite/goethite molar ratios varied from 0 to 1.4, and within the 880-898 nm range, T1 features were used to estimate hematite/goethite molar ratios. Post-mission X-ray analysis detected phyllosilicates, which indicates that examining beyond the VNIR (e.g., shortwave infrared, 1000-2500 nm) will enhance the detection of other minerals formed by aqueous processes. Despite the limited spectral range of VNIR point spectrometry utilized in the MARTE Mars drilling simulation project, ferric iron minerals could be identified in retrieved core material, and their distribution served to direct core subsampling for biological analysis.

  14. Miners' welfare

    Energy Technology Data Exchange (ETDEWEB)

    Buckley, C

    1984-06-13

    The Miners' Welfare Committee (MWC) was formed in Britain in 1921 and initiated building programmes to provide welfare amenities for miners and families, using architecture to improve the quality of a miner's working and leisure time. The article reviews the MWC's work, and assesses the design and architecture at the Selby Coalfield. (7 refs.)

  15. Automated mineralogical logging of coal and coal measure core

    Energy Technology Data Exchange (ETDEWEB)

    Stephen Fraser; Joan Esterle; Colin Ward; Ruth Henwood; Peter Mason; Jon Huntington; Phil Connor; Reneta Sliwa; Dave Coward; Lew Whitbourn [CSIRO Exploration & Mining (Australia)

    2006-06-15

    A mineralogical core logging system based on spectral reflectance (HyLogger{trademark}) has been used to detect and quantify mineralogies in coal and coal measure sediments. The HyLogger{trademark} system, as tested, operates in the visible-to-shortwave infrared spectral region, where iron oxides, sulphates, hydroxyl-bearing and carbonate minerals have characteristic spectral responses. Specialized software assists with mineral identification and data display. Three Phases of activity were undertaken. In Phase I, carbonates (siderite, ankerite, calcite) and clays (halloysite, dickite) were successfully detected and mapped in coal. Repeat measurements taken from one of the cores after three months demonstrated the reproducibility of the spectral approach, with some spectral differences being attributed to variations in moisture content and oxidation. Also, investigated was HyLogger{trademark} ability to create a 'brightness-profile' on coal materials, and these results were encouraging. In Phase II, geotechnically significant smectitic clays (montmorillonite) were detected and mapped in cores of clastic roof and floor materials. Such knowledge would be useful for mine planning and design purposes. In Phase III, our attempts at determining whether phosphorus-bearing minerals such as apatite could be spectrally detected were less than conclusive. A spectral index could only be created for apatite, and the relationships between the spectrally-derived apatite-index, the XRD results and the analytically-derived phosphorus measurements were ambiguous.

  16. A combined vector potential-scalar potential method for FE computation of 3D magnetic fields in electrical devices with iron cores

    Science.gov (United States)

    Wang, R.; Demerdash, N. A.

    1991-01-01

    A method of combined use of magnetic vector potential based finite-element (FE) formulations and magnetic scalar potential (MSP) based formulations for computation of three-dimensional magnetostatic fields is introduced. In this method, the curl-component of the magnetic field intensity is computed by a reduced magnetic vector potential. This field intensity forms the basic of a forcing function for a global magnetic scalar potential solution over the entire volume of the region. This method allows one to include iron portions sandwiched in between conductors within partitioned current-carrying subregions. The method is most suited for large-scale global-type 3-D magnetostatic field computations in electrical devices, and in particular rotating electric machinery.

  17. Phytases for improved iron absorption

    DEFF Research Database (Denmark)

    Nielsen, Anne Veller Friis; Meyer, Anne S.

    2016-01-01

    Phytase enzymes present an alternative to iron supplements, because they have been shown to improve iron absorption by means of catalysing the degradation of a potent iron absorption inhibitor: phytic acid. Phytic acid is a hexaphosphate of inositol and is particularly prevalent in cereal grains......, where it serves as a storage molecule for phosphorous. Phytic acid is also associated with minerals. The minerals are bound by chelation to the negatively charged phosphate groups in phytic acid. Phytases catalyse the dephosphorylation of phytic acid, thus releasing bound minerals to make them available...... for absorption. This article presents research on phytase catalysis in gastric conditions and considers potential benefits and drawbacks for using phytases as a food supplement....

  18. The earths innermost core

    International Nuclear Information System (INIS)

    Nanda, J.N.

    1989-01-01

    A new earth model is advanced with a solid innermost core at the centre of the Earth where elements heavier than iron, over and above what can be retained in solution in the iron core, are collected. The innermost core is separated from the solid iron-nickel core by a shell of liquid copper. The innermost core has a natural vibration measured on the earth's surface as the long period 26 seconds microseisms. The earth was formed initially as a liquid sphere with a relatively thin solid crust above the Byerly discontinuity. The trace elements that entered the innermost core amounted to only 0.925 ppm of the molten mass. Gravitational differentiation must have led to the separation of an explosive thickness of pure 235 U causing a fission explosion that could expel beyond the Roche limit a crustal scab which would form the centre piece of the moon. A reservoir of helium floats on the liquid copper. A small proportion of helium-3, a relic of the ancient fission explosion present there will spell the exciting magnetic field. The field is stable for thousands of years because of the presence of large quantity of helium-4 which accounts for most of the gaseous collisions that will not disturb the atomic spin of helium-3 atoms. This field is prone to sudden reversals after long periods of stability. (author). 14 refs

  19. Geology of the Biwabik Iron Formation and Duluth Complex.

    Science.gov (United States)

    Jirsa, Mark A; Miller, James D; Morey, G B

    2008-10-01

    The Biwabik Iron Formation is a approximately 1.9 billion year-old sequence of iron-rich sedimentary rocks that was metamorphosed at its eastern-most extent by approximately 1.1 billion year-old intrusions of the Duluth Complex. The metamorphic recrystallization of iron-formation locally produced iron-rich amphiboles and other fibrous iron-silicate minerals. The presence of these minerals in iron-formation along the eastern part of what is known as the Mesabi Iron Range, and their potential liberation by iron mining has raised environmental health concerns. We describe here the geologic setting and mineralogic composition of the Biwabik Iron Formation in and adjacent to the contact metamorphic aureole of the Duluth Complex. The effects of metamorphism are most pronounced within a few kilometers of the contact, and decrease progressively away from it. The contact aureole has been divided into four metamorphic zones-each characterized by the composition and crystal structure of the metamorphic minerals it contains. The recrystallization of iron-formation to iron-rich amphibole minerals (grunerite and cummingtonite) and iron-pyroxene minerals (hedenbergite and ferrohypersthene) is best developed in zones that are most proximal to the Duluth Complex contact.

  20. Sorption of pesticides to aquifer minerals

    DEFF Research Database (Denmark)

    Clausen, Liselotte; Fabricius, Ida Lykke

    2000-01-01

    This paper summarizes results from a work were the sorption of five pesticides on seven minerals were studied in order to quantify the adsorption to different mineral surfaces. Investigated mineral phases are: quartz, calcite, kaolinite, a-alumina, and three iron oxides (2-line ferrihydrite......, goethite, lepidocrocite). Selected pesticides are: atrazine, isoproturon, mecoprop, 2,4-D, and bentazone. The results demonstrate that pesticides adsorb to pure mineral surfaces. However, the size of the adsorption depends on the type of pesticide and the type of mineral....

  1. Iron, transferrin and myelinogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Sergeant, C. E-mail: sergeant@cenbg.in2p3.fr; Vesvres, M.H.; Deves, G.; Baron, B.; Guillou, F

    2003-09-01

    Transferrin (Tf), the iron binding protein of vertebrates serum, is known to be synthesized by oligodendrocytes (Ols) in the central nervous system. It has been postulated that Tf is involved in Ols maturation and myelinogenesis. This link is particularly important in the understanding of a severe human pathology: the multiple sclerosis, which remains without efficient treatment. We generated transgenic mice containing the complete human Tf gene and extensive regulatory sequences from the 5{sup '} and 3{sup '} untranslated regions that specifically overexpress Tf in Ols. Brain cytoarchitecture of the transgenic mice appears to be normal in all brain regions examined, total myelin content is increased by 30% and motor coordination is significantly improved when compared with non-transgenic littermates. Tf role in the central nervous system may be related to its affinity for metallic cations. Normal and transgenic mice were used for determination of trace metals (iron, copper and zinc) and minerals (potassium and calcium) concentration in cerebellum and corpus callosum. The freeze-dried samples were prepared to allow proton-induced X-ray emission and Rutherford backscattering spectrometry analyses with the nuclear microprobe in Bordeaux. Preliminary results were obtained and carbon distribution was revealed as a very good analysis to distinguish precisely the white matter region. A comparison of metallic and mineral elements contents in brain between normal and transgenic mice shows that iron, copper and zinc levels remained constant. This result provides evidence that effects of Tf overexpression in the brain do not solely relate to iron transport.

  2. Iron, transferrin and myelinogenesis

    International Nuclear Information System (INIS)

    Sergeant, C.; Vesvres, M.H.; Deves, G.; Baron, B.; Guillou, F.

    2003-01-01

    Transferrin (Tf), the iron binding protein of vertebrates serum, is known to be synthesized by oligodendrocytes (Ols) in the central nervous system. It has been postulated that Tf is involved in Ols maturation and myelinogenesis. This link is particularly important in the understanding of a severe human pathology: the multiple sclerosis, which remains without efficient treatment. We generated transgenic mice containing the complete human Tf gene and extensive regulatory sequences from the 5 ' and 3 ' untranslated regions that specifically overexpress Tf in Ols. Brain cytoarchitecture of the transgenic mice appears to be normal in all brain regions examined, total myelin content is increased by 30% and motor coordination is significantly improved when compared with non-transgenic littermates. Tf role in the central nervous system may be related to its affinity for metallic cations. Normal and transgenic mice were used for determination of trace metals (iron, copper and zinc) and minerals (potassium and calcium) concentration in cerebellum and corpus callosum. The freeze-dried samples were prepared to allow proton-induced X-ray emission and Rutherford backscattering spectrometry analyses with the nuclear microprobe in Bordeaux. Preliminary results were obtained and carbon distribution was revealed as a very good analysis to distinguish precisely the white matter region. A comparison of metallic and mineral elements contents in brain between normal and transgenic mice shows that iron, copper and zinc levels remained constant. This result provides evidence that effects of Tf overexpression in the brain do not solely relate to iron transport

  3. Models of the earth's core

    Science.gov (United States)

    Stevenson, D. J.

    1981-01-01

    Combined inferences from seismology, high-pressure experiment and theory, geomagnetism, fluid dynamics, and current views of terrestrial planetary evolution lead to models of the earth's core with five basic properties. These are that core formation was contemporaneous with earth accretion; the core is not in chemical equilibrium with the mantle; the outer core is a fluid iron alloy containing significant quantities of lighter elements and is probably almost adiabatic and compositionally uniform; the more iron-rich inner solid core is a consequence of partial freezing of the outer core, and the energy release from this process sustains the earth's magnetic field; and the thermodynamic properties of the core are well constrained by the application of liquid-state theory to seismic and labroatory data.

  4. Natural resources sustainability: iron ore mining

    International Nuclear Information System (INIS)

    De La Torre de Palacios, Luis

    2011-01-01

    In the present article, a new tool to determine environmental sustainability, the energy impact index (EII) was developed to classify different iron mine projects according to two main parameters including energy consumption and CO 2 emissions. The EII considers the characteristics of the mineral (such as the quality, size, hardness, iron ore grade, reducibility, mineral/waste rate, and type of deposit), mining processes (type of exploitation, ore processing, available technology), and transportation (distance to cover).

  5. Purification and characterization of an iron-induced ferritin from soybean (Glycine max) cell suspensions.

    Science.gov (United States)

    Lescure, A M; Massenet, O; Briat, J F

    1990-11-15

    Ferric citrate induces ferritin synthesis and accumulation in soybean (Glycine max) cell suspension cultures [Proudhon, Briat & Lescure (1989) Plant Physiol. 90, 586-590]. This iron-induced ferritin has been purified from cells grown for 72 h in the presence of either 100 microM- or 500 microM-ferric citrate. It has a molecular mass of about 600 kDa and is built up from a 28 kDa subunit which is recognized by antibodies raised against pea (Pisum sativum) seed ferritin and it has the same N-terminal sequence as this latter, except for residue number 3, which is alanine in pea seed ferritin instead of valine in iron-induced soybean cell ferritin. It contains an average of 1800 atoms of iron per molecule whatever the ferric citrate concentration used to induce its synthesis. It is shown that the presence of 100 microM- or 500 microM-ferric citrate in the culture medium leads respectively to an 11- and 28-fold increase in the total intracellular iron concentration and to a 30- and 60-fold increase in the ferritin concentration. However, the percentage of iron stored in the mineral core of ferritin remains constant whatever the ferric citrate concentration used and represents only 5-6% of cellular iron.

  6. Evaluation of the influence of UV/IR radiation on iron release from ferritin

    International Nuclear Information System (INIS)

    Gritzkov, M.; Kochev, V.; Vladimirova, L

    2010-01-01

    In the present work the influence of UV/IR radiation on the iron-releasing process from ferritin is investigated. The ferritins are a family of iron-storing proteins playing a key role in the biochemical reactions between iron and oxygen-processes of exclusive importance for the existence of all living organisms. The iron is stored within the ferritin core in the form of insoluble crystals containing Fe(III). Therefore for its release, the mineral matrix has to be decomposed, usually through a reduction of Fe(III) to Fe(II). Our study considers the action of UV/IR radiation on the structure of the protein molecule. Eventual changes in the ferritin conformation under the irradiation could result in the change of channel forming regions responsible for the iron efflux. This can be assess by the quantity of Fe (II) obtained in a subsequent mobilization procedure evoked by exogenous reducing agents. In our case the content of the reduced iron is determined electrochemically by the method of potentiometric titration. As already was shown, this method promises to become highly useful for quantitative evaluation of released Fe 2+ . (Author)

  7. Chladniite: A New Mineral Honoring the Father of Meteoritics

    Science.gov (United States)

    McCoy, T. J.; Steele, I. M.; Keil, K.; Leonard, B. F.; Endress, M.

    1993-07-01

    cell. A total of 17 lines were observed in the powder pattern. Chladniite is hexagonal, R 3(bar), a = 14.967 angstroms, c = 42.595 angstroms, beta = 120 degrees. Attempts to determine the structure of chladniite are in progress. Chladniite is named for Ernst Florens Friedrich Chladni (1756-1827), who is widely regarded as the "Father of Meteoritics." After his initial training as a lawyer, Chladni turned his attention to science, particularly problems in acoustics. He was not, however, able to obtain a permanent position and embarked upon the life of a nomad, traveling among the great cities of Europe lecturing about acoustics. During these travels, he eventually gained an interest in meteoritics. It was Chladni's pioneering book of 1794 that, for the first time, presented strong evidence for an extraterrestrial origin of meteoritic stones and irons [5]. In addition, Chladni argued that meteorites must have been the building blocks of all planets and argued that a large iron core must exist inside the Earth. During his extensive travels, Chladni also established a meteorite collection that can still be seen at Humboldt University in Berlin. It is appropriate that a mineral be named in his honor as we approach the 200th anniversary of the publication of his monumental work. References: [1] McCoy et al. (1993) Meteoritics, in press. [2] Fuchs et al. (1967) GCA, 21, 1711-1719. [3] Araki and Moore (1981) Am. Mineral., 66, 827-842. [4] Livingstone (1980) Min. Mag., 43, 833-836. [5] Chladni (1794) Riga, J. F. Hartknoch (in German); reprinted (with introduction by G. Hoppe) by Akad. Verlagsgesellschaft Geest & Portig K.-G. (1982) (in German).

  8. Hyperspectral surface materials map of quadrangles 2964, 2966, 3064, and 3066, Shah-Esmail (617), Reg-Alaqadari (618), Samandkhan-Karez (713), Laki-Bander (611), Jahangir-Naweran (612), and Sreh-Chena (707) quadrangles, Afghanistan, showing iron-bearing minerals and other materials

    Science.gov (United States)

    Hoefen, Todd M.; King, Trude V.V.; Kokaly, Raymond F.; Livo, Keith E.; Giles, Stuart A.; Johnson, Michaela R.

    2013-01-01

    This map shows the spatial distribution of selected iron-bearing minerals and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. This map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Goethite and jarosite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  9. Oncoidal granular iron formation in the Mesoarchaean Pongola Supergroup, southern Africa: Textural and geochemical evidence for biological activity during iron deposition.

    Science.gov (United States)

    Smith, A J B; Beukes, N J; Gutzmer, J; Czaja, A D; Johnson, C M; Nhleko, N

    2017-11-01

    We document the discovery of the first granular iron formation (GIF) of Archaean age and present textural and geochemical results that suggest these formed through microbial iron oxidation. The GIF occurs in the Nconga Formation of the ca. 3.0-2.8 Ga Pongola Supergroup in South Africa and Swaziland. It is interbedded with oxide and silicate facies micritic iron formation (MIF). There is a strong textural control on iron mineralization in the GIF not observed in the associated MIF. The GIF is marked by oncoids with chert cores surrounded by magnetite and calcite rims. These rims show laminated domal textures, similar in appearance to microstromatolites. The GIF is enriched in silica and depleted in Fe relative to the interbedded MIF. Very low Al and trace element contents in the GIF indicate that chemically precipitated chert was reworked above wave base into granules in an environment devoid of siliciclastic input. Microbially mediated iron precipitation resulted in the formation of irregular, domal rims around the chert granules. During storm surges, oncoids were transported and deposited in deeper water environments. Textural features, along with positive δ 56 Fe values in magnetite, suggest that iron precipitation occurred through incomplete oxidation of hydrothermal Fe 2+ by iron-oxidizing bacteria. The initial Fe 3+ -oxyhydroxide precipitates were then post-depositionally transformed to magnetite. Comparison of the Fe isotope compositions of the oncoidal GIF with those reported for the interbedded deeper water iron formation (IF) illustrates that the Fe 2+ pathways and sources for these units were distinct. It is suggested that the deeper water IF was deposited from the evolved margin of a buoyant Fe 2+ aq -rich hydrothermal plume distal to its source. In contrast, oncolitic magnetite rims of chert granules were sourced from ambient Fe 2+ aq -depleted shallow ocean water beyond the plume. © 2017 John Wiley & Sons Ltd.

  10. Dissolution and secondary mineral precipitation in basalts due to reactions with carbonic acid

    Science.gov (United States)

    Kanakiya, Shreya; Adam, Ludmila; Esteban, Lionel; Rowe, Michael C.; Shane, Phil

    2017-06-01

    One of the leading hydrothermal alteration processes in volcanic environments is when rock-forming minerals with high concentrations of iron, magnesium, and calcium react with CO2 and water to form carbonate minerals. This is used to the advantage of geologic sequestration of anthropogenic CO2. Here we experimentally investigate how mineral carbonation processes alter the rock microstructure due to CO2-water-rock interactions. In order to characterize these changes, CO2-water-rock alteration in Auckland Volcanic Field young basalts (less than 0.3 Ma) is studied before and after a 140 day reaction period. We investigate how whole core basalts with similar geochemistry but different porosity, permeability, pore geometry, and volcanic glass content alter due to CO2-water-rock reactions. Ankerite and aluminosilicate minerals precipitate as secondary phases in the pore space. However, rock dissolution mechanisms are found to dominate this secondary mineral precipitation resulting in an increase in porosity and decrease in rigidity of all samples. The basalt with the highest initial porosity and volcanic glass volume shows the most secondary mineral precipitation. At the same time, this sample exhibits the greatest increase in porosity and permeability, and a decrease in rock rigidity post reaction. For the measured samples, we observe a correlation between volcanic glass volume and rock porosity increase due to rock-fluid reactions. We believe this study can help understand the dynamic rock-fluid interactions when monitoring field scale CO2 sequestration projects in basalts.

  11. Extending hydraulic lifetime of iron walls

    International Nuclear Information System (INIS)

    Mackenzie, P.D.; Sivavec, T.M.; Horney, D.P.

    1997-01-01

    Iron walls for control of groundwaters contaminated with chlorinated solvents and reducible metals are becoming much more widely used and field studies of this technology have proven successful to date. However, there is still much uncertainty in predicting long-term performance. This work focuses on two factors affecting the lifetime of the iron media: plugging at the treatment zone entrance and precipitation in the bulk iron media. Plugging at the system entrance is due principally to dissolved oxygen in the incoming water and is an issue in aerobic aquifers or in ex-situ canister tests. In an in-situ treatment system, plugging would result in a dramatic reduction in flow through the iron zone. Designs to minimize plugging in field applications include use of larger iron particles and admixing sand of comparable size with the iron particles. Mineral precipitation in the bulk iron media can lead to porosity losses in the media, again reducing flow through the treatment zone. Decreases in reactivity of the iron media may also occur. The nature of the mineral precipitation and the factors that affect extent of mineral precipitation are examined by a variety of tools, including tracer tests, aqueous inorganic profiles, and surface analysis techniques. At short treatment times, measured porosity losses are due mainly to entrapment of a film of H 2 gas on the iron surfaces and also to Fe(OH) 2 precipitation. Over longer treatment times precipitation of Fe(OH) 2 and FeCO 3 in low carbonate waters and of Fe(OH) 2 , FeCO 3 and CaCO 3 in higher carbonate waters will begin to dominate porosity losses. Preliminary results of an on-going study to control pH in an iron zone by admixing iron sulfide with iron show no difference in extent of carbonate precipitation versus a 100% iron system, suggesting that these systems are supersaturated with respect to carbonate precipitation

  12. Accelerated dissolution of iron oxides in ice

    Directory of Open Access Journals (Sweden)

    D. Jeong

    2012-11-01

    Full Text Available Iron dissolution from mineral dusts and soil particles is vital as a source of bioavailable iron in various environmental media. In this work, the dissolution of iron oxide particles trapped in ice was investigated as a new pathway of iron supply. The dissolution experiments were carried out in the absence and presence of various organic complexing ligands under dark condition. In acidic pH conditions (pH 2, 3, and 4, the dissolution of iron oxides was greatly enhanced in the ice phase compared to that in water. The dissolved iron was mainly in the ferric form, which indicates that the dissolution is not a reductive process. The extent of dissolved iron was greatly affected by the kind of organic complexing ligands and the surface area of iron oxides. The iron dissolution was most pronounced with high surface area iron oxides and in the presence of strong iron binding ligands. The enhanced dissolution of iron oxides in ice is mainly ascribed to the "freeze concentration effect", which concentrates iron oxide particles, organic ligands, and protons in the liquid like ice grain boundary region and accelerates the dissolution of iron oxides. The ice-enhanced dissolution effect gradually decreased when decreasing the freezing temperature from −10 to −196 °C, which implies that the presence and formation of the liquid-like ice grain boundary region play a critical role. The proposed phenomenon of enhanced dissolution of iron oxides in ice may provide a new pathway of bioavailable iron production. The frozen atmospheric ice with iron-containing dust particles in the upper atmosphere thaws upon descending and may provide bioavailable iron upon deposition onto the ocean surface.

  13. The role of iron-sulfides on cycling of organic carbon in the St Lawrence River system: Evidence of sulfur-promoted carbon sequestration?

    Science.gov (United States)

    Balind, K.; Barber, A.; Gélinas, Y.

    2017-12-01

    The biogeochemical cycle of sulfur is intimately linked with that of carbon, as well as with that of iron through the formation of iron-sulfur complexes. Iron-sulfide minerals such as mackinawite (FeS) and greigite (Fe3S4) form below the oxic/anoxic redox boundary in marine and lacustrine sediments and soils. Reactive iron species, abundant in surface sediments, can undergo reductive dissolution leading to the formation of soluble Fe(II) which can then precipitate in the form of iron sulfur species. While sedimentary iron-oxides have been thoroughly explored in terms of their ability to sorb and sequester organic carbon (OC) (Lalonde et al.; 2012), the role of FeS in the long-term preservation of OC remains undefined. In this study, we present depth profiles for carbon, iron, and sulfur in the aqueous-phase, along with data from sequential extractions of sulfur speciation in the solid-phase collected from sediment cores from the St Lawrence River and estuarine system, demonstrating the transition from fresh to saltwater sediments. Additionally, we present synthetic iron sulfur sorption experiments using both model and natural organic molecules in order to assess the importance of FeS in sedimentary carbon storage.

  14. BET measurements: Outgassing of minerals

    DEFF Research Database (Denmark)

    Clausen, Liselotte; Fabricius, Ida Lykke

    2000-01-01

    Outgassing minerals at elevated temperatures prior to BET measurements can lead to phase changes, especially in the case of amorphous and poorly crystalline materials. In order to evaluate the applicability of the BET method when low outgassing temperatures are required, selected aquifer minerals...... were outgassed at different temperatures and for different times. The studied minerals are 2-line ferrihydrite, goethite, lepidocrocite, quartz, calcite, ®-alumina, and kaolinite. The results demonstrate that measured specific surface areas of iron oxides are strongly dependent on outgassing conditions...... because the surface area increased by 170% with increasing temperature. In the poorly crystalline minerals, phase changes caused by heating were observed at temperatures lower than 100±C. Therefore low outgassing temperatures are preferable for minimizing phase changes. As demonstrated in this study...

  15. Models of the earth's core

    International Nuclear Information System (INIS)

    Stevenson, D.J.

    1981-01-01

    The combination of seismology, high pressure experiment and theory, geomagnetism, fluid dynamics, and current views of terrestrial planetary evolution lead to strong constraints on core models. The synthesis presented here is devoted to the defense of the following properties: (1) core formation was contemporaneous with earth accretion; (2) the outer, liquid core is predominately iron but cannot be purely iron; (3) the inner core-outer core boundary represents a thermodynamic equilibrium between a liquid alloys and a predominanately iron solid; (4) thermodynamic and transport properties of outer core can be estimated from liquid-state theories; and (5) the outer core is probably adiabatic and uniform in composition. None of these propositions are universally accepted by geophysicists. But, the intent of this paper is to present a coherent picture which explains most of the data with the fewest ad hoc assumptions. Areas in which future progress is both essential and likely are geo- and cosmochronology, seismological determinations of core structure, fluid dynamics of the core and mantle, and condensed matter physics

  16. Terrestrial magma ocean and core segregation in the earth

    Science.gov (United States)

    Ohtani, Eiji; Yurimoto, Naoyoshi

    1992-01-01

    According to the recent theories of formation of the earth, the outer layer of the proto-earth was molten and the terrestrial magma ocean was formed when its radius exceeded 3000 km. Core formation should have started in this magma ocean stage, since segregation of metallic iron occurs effectively by melting of the proto-earth. Therefore, interactions between magma, mantle minerals, and metallic iron in the magma ocean stage controlled the geochemistry of the mantle and core. We have studied the partitioning behaviors of elements into the silicate melt, high pressure minerals, and metallic iron under the deep upper mantle and lower mantle conditions. We employed the multi-anvil apparatus for preparing the equilibrating samples in the ranges from 16 to 27 GPa and 1700-2400 C. Both the electron probe microanalyzer (EPMA) and the Secondary Ion Mass spectrometer (SIMS) were used for analyzing the run products. We obtained the partition coefficients of various trace elements between majorite, Mg-perovskite, and liquid, and magnesiowustite, Mg-perovskite, and metallic iron. The examples of the partition coefficients of some key elements are summarized in figures, together with the previous data. We may be able to assess the origin of the mantle abundances of the elements such as transition metals by using the partitioning data obtained above. The mantle abundances of some transition metals expected by the core-mantle equilibrium under the lower mantle conditions cannot explain the observed abundance of some elements such as Mn and Ge in the mantle. Estimations of the densities of the ultrabasic magma Mg-perovskite at high pressure suggest existence of a density crossover in the deep lower mantle; flotation of Mg-perovskite occurs in the deep magma ocean under the lower mantle conditions. The observed depletion of some transition metals such as V, Cr, Mn, Fe, Co, and Ni in the mantle may be explained by the two stage process, the core-mantle equilibrium under the lower

  17. Investigation of microbial-mineral interactions by Moessbauer spectroscopy

    International Nuclear Information System (INIS)

    Sawicki, J.A.; Brown, D.A.

    1998-01-01

    Moessbauer spectroscopy was used to investigate the reactions of microbes with iron minerals in aqueous solutions and as components of rocks in banded iron formations and granite. A microbial biofilm that formed on a wall of an excavated granite vault in a deep underground laboratory initiated this research. At the aerobic face of the biofilm, iron was found in a form of ferrihydrite; in the anaerobic face against the rock, iron was found as very small siderite particles. Laboratory incubations of the biofilm microbial consortium showed different mineral species could be formed. When the microbial consortium from the biofilm was incubated with magnetite grains, up to about 10% of the iron was altered in three weeks to hematite. The ability of the consortium to precipitate iron both as Fe 2+ and Fe 3+ in close proximity may have a bearing on the deposition of banded iron formations. These reactions could also be important in microbially induced corrosion

  18. Far infrared extinction coefficients of minerals of interest for astronomical observations

    International Nuclear Information System (INIS)

    Hasegawa, H.

    1984-01-01

    Far infrared extinction coefficients of mineral grains of interest for astronomical observations have been measured. The measured mineral species are: amorphous carbon, high temperature magnesium silicates, hydrous silicates, iron oxides, and amorphous silicates. (author)

  19. One-stop shopping in Africa's minerals supermarket

    International Nuclear Information System (INIS)

    Spira, J.

    1980-01-01

    Johannesburg in South Africa is one of the minerals capitals of the world, providing a one-stop shopping supermarket for the most sought-after strategic minerals. Total annual mineral sales grew from R1563 million in 1970 to R6876 million in 1978. For 1979 the figure exceeded R9700 million. Production, trade and marketing of gold, coal, platinum, uranium, diamonds, iron ore, copper, antimony, mineral sands, asbestos and vanadium are shortly discussed

  20. Evaluation of stator core loss of high speed motor by using thermography camera

    Science.gov (United States)

    Sato, Takeru; Enokizono, Masato

    2018-04-01

    In order to design a high-efficiency motor, the iron loss that is generated in the motor should be reduced. The iron loss of the motor is generated in a stator core that is produced with an electrical steel sheet. The iron loss characteristics of the stator core and the electrical steel sheet are agreed due to a building factor. To evaluate the iron loss of the motor, the iron loss of the stator core should be measured more accurately. Thus, we proposed the method of the iron loss evaluation of the stator core by using a stator model core. This stator model core has been applied to the surface mounted permanent magnet (PM) motors without windings. By rotate the permanent magnet rotor, the rotating magnetic field is generated in the stator core like a motor under driving. To evaluate the iron loss of the stator model core, the iron loss of the stator core can be evaluated. Also, the iron loss can be calculated by a temperature gradient. When the temperature gradient is measured by using thermography camera, the iron loss of entire stator core can be evaluated as the iron loss distribution. In this paper, the usefulness of the iron loss evaluation method by using the stator model core is shown by the simulation with FEM and the heat measurement with thermography camera.

  1. Aggregate and Mineral Resources - Minerals

    Data.gov (United States)

    NSGIC State | GIS Inventory — This point occurrence data set represents the current mineral and selected energy resources of Utah. The data set coordinates were derived from USGS topographic maps...

  2. Mineral Chart

    Science.gov (United States)

    ... anemia include weakness and fatigue, lightheadedness, and shortness of breath. Iron-rich foods include red meat, pork, fish and shellfish, poultry, lentils, beans and soy foods, green leafy vegetables, and raisins. Some flours, cereals, and grain products are also fortified with ...

  3. Cast irons

    CERN Document Server

    1996-01-01

    Cast iron offers the design engineer a low-cost, high-strength material that can be easily melted and poured into a wide variety of useful, and sometimes complex, shapes. This latest handbook from ASM covers the entire spectrum of one of the most widely used and versatile of all engineered materials. The reader will find the basic, but vital, information on metallurgy, solidification characteristics, and properties. Extensive reviews are presented on the low-alloy gray, ductile, compacted graphite, and malleable irons. New and expanded material has been added covering high-alloy white irons used for abrasion resistance and high-alloy graphitic irons for heat and corrosion resistance. Also discussed are melting furnaces and foundry practices such as melting, inoculation, alloying, pouring, gating and rising, and molding. Heat treating practices including stress relieving, annealing, normalizing, hardening and tempering, autempering (of ductile irons), and surface-hardening treatments are covered, too. ASM Spec...

  4. Ice nucleation by surrogates for atmospheric mineral dust and mineral dust/sulfate particles at cirrus temperatures

    Directory of Open Access Journals (Sweden)

    C. M. Archuleta

    2005-01-01

    Full Text Available This study examines the potential role of some types of mineral dust and mineral dust with sulfuric acid coatings as heterogeneous ice nuclei at cirrus temperatures. Commercially-available nanoscale powder samples of aluminum oxide, alumina-silicate and iron oxide were used as surrogates for atmospheric mineral dust particles, with and without multilayer coverage of sulfuric acid. A sample of Asian dust aerosol particles was also studied. Measurements of ice nucleation were made using a continuous-flow ice-thermal diffusion chamber (CFDC operated to expose size-selected aerosol particles to temperatures between -45 and -60°C and a range of relative humidity above ice-saturated conditions. Pure metal oxide particles supported heterogeneous ice nucleation at lower relative humidities than those required to homogeneously freeze sulfuric acid solution particles at sizes larger than about 50 nm. The ice nucleation behavior of the same metal oxides coated with sulfuric acid indicate heterogeneous freezing at lower relative humidities than those calculated for homogeneous freezing of the diluted particle coatings. The effect of soluble coatings on the ice activation relative humidity varied with the respective uncoated core particle types, but for all types the heterogeneous freezing rates increased with particle size for the same thermodynamic conditions. For a selected size of 200 nm, the natural mineral dust particles were the most effective ice nuclei tested, supporting heterogeneous ice formation at an ice relative humidity of approximately 135%, irrespective of temperature. Modified homogeneous freezing parameterizations and theoretical formulations are shown to have application to the description of heterogeneous freezing of mineral dust-like particles with soluble coatings.

  5. Niger Republic mineral planning : Part four Second volume : Main mineral substances specific study and their geological context

    International Nuclear Information System (INIS)

    Franconi, Antoine; Joo', Julien; Zibo, Idde

    1981-01-01

    This volume describes Niger Republic mineral substances capable of rising economic interest. After relating minerals occurrence , indices and deposits types, conclusions and recommendations have been made for mineral prospecting. Mineral substances described are : Copper, lead and zinc, molybdena, iron, manganese, titanium, vanadium, nickel and chrome ( cobalt and platinoid ), lithium, lignite, diamond and diverse substances rare earth, beryllium, silver, bismuth arsenic and antimony, barytine, alunite, talc and asbestos ( graphite and diatomite) [fr

  6. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... risk for iron-deficiency anemia, including: Vegetarian or vegan eating patterns. Not eating enough iron-rich foods, ... iron-fortified foods that have iron added. Vegetarian diets can provide enough iron if you choose nonmeat ...

  7. Atmospheric processing of combustion aerosols as a source of soluble iron to the open ocean

    OpenAIRE

    伊藤, 彰記; ITO, Akinori

    2015-01-01

    The majority of bioavailable iron (Fe) from the atmosphere is delivered from arid and semiarid regions to the oceans because the global deposition of iron from combustion sources is small compared with that from mineral dust. Atmospheric processing of mineral aerosols by inorganic and organic acids from anthropogenic and natural sources has been shown to increase the iron solubility of soils (initially < 0.5%) up to about 10%. On the other hand, atmospheric observations have shown that iron i...

  8. Fumarolic minerals

    DEFF Research Database (Denmark)

    Balic Zunic, Tonci; Garavelli, Anna; Jakobsson, Sveinn Peter

    2016-01-01

    The fumarolic mineralogy of the Icelandic active volcanoes, the Tyrrhenian volcanic belt (Italy) and the Aegean active arc (Greece) is investigated, and literature data surveyed in order to define the characteristics of the European fumarolic systems. They show broad diversity of mineral...... associations, with Vesuvius and Vulcano being also among the world localities richest in mineral species. Volcanic systems, which show recession over a longer period, show fumarolic development from the hightemperature alkaline halide/sulphate, calcic sulphate or sulphidic parageneses, synchronous...... with or immediately following the eruptions, through mediumtemperature ammonium minerals, metal chlorides, or fluoride associations to the late low-temperature paragenesis dominated by sulphur, gypsum, alunogen, and other hydrous sulphates. The situation can be different in the systems that are not recessing but show...

  9. Mineral sands

    International Nuclear Information System (INIS)

    Anon.

    1990-01-01

    This paper presents an outlook of the Australian mineral sand industry and covers the major operators. It is shown that conscious of an environmentally minded public, the Australian miners have led the way in the rehabilitation of mined areas. Moreover the advanced ceramic industry is generating exciting new perspectives for zircon producers and there is a noticeable growth in the electronic market for rare earths, but in long term the success may depend as much on environmental management and communication skills as on mining and processing skills

  10. Minerals yearbook: The mineral industry of Brazil. 1988 international review

    International Nuclear Information System (INIS)

    Ensminger, H.R.

    1988-01-01

    Brazil's gross domestic product (GDP) grew only slightly in 1988 to $277 billion at current prices. The growth rate was the smallest registered since 1983, when the rate was minus 2.8%. The economy's performance was strongly influenced by a 2% to 3% decrease in industrial production and civil construction. The mineral industry, however, countered the downward trend in the industrial sector and grew a modest 1.4%. Topics discussed in the report include the following: Government policies and programs; Production; Trade; Commodity review--Metals (Aluminum, Aluminia, and Bauxite, Columbium, Copper, Gold, Iron and Steel, Manganese, Tin, Titanium); Industrial Minerals (Gem stones, Phosphate rock, Quartz); Mineral fuels (Coal, Natural gas, Petroleum, Nuclear power); Nonmineral energy sources (Alcohol, Hydroelectric)

  11. Study of fluid inclusions in rodioactive mineralized pegmatites, dara area northern eastern desert, Egypt

    International Nuclear Information System (INIS)

    Ali, B.H.; Abdel Warith, A.

    2003-01-01

    Numerous pegmatite pockets of un zoned and zoned types are the most important rock types from the radioactive point of view. They occur at the marginal parts and higher topographic level of G.Dara younger granites. Zoned pegmatites are composed of extremely coarse-grained milky quartz core, intermediate zone and wall zone. The alteration zone is found at the contact between quartz core and intermediate zone. It is recorded the highest radioactive values due to their mineral composition, as a result of alteration processes associated with radioactive minerals. Only two alteration zones (P1 and P2) has been studied in this paper. The late magmatic alteration process (hematization, kaolinization, chloritization and fluortization) of the pegmatite resulted in the formation of chlorite, fluorite, clay minerals and carbonates (calcite) in the alteration zones as mineral assemblage. opaque minerals are found as pyrite, iron oxyhydroxide and garnet. Fluid inclusion studies by microthermometry were carried out on authigenic minerals (such as quartz and fluorite) in alteration zones (primary fluid inclusions). This study revealed that, at least two stages of the post-magmatic hydrothermal alteration are involved. The first stages of high temperature, low saline fluids are involved. The first stage is of high temperature, low saline fluids which characterized with hematization and/or chloritization resulted from fluid-rock interaction with late magmatic fluids that very probably mixed with external low salinity fluids along brittle structure. The second stage is of low temperature the main role in re high saline fluids characterized the fluoritized alteration due to consequent reaction with wall rocks and mixing with meteoric water. Mixing of low salinity meteoric water with hot a sending saline hydrothermal solution leads to ph change and continuous interaction with wall rock

  12. Canadian minerals yearbook : 2004 review and outlook

    International Nuclear Information System (INIS)

    2004-01-01

    The main focus of the CMY publication is the non-fuel mineral industry, together with uranium, although all mineral fuels are normally included when the total value of Canada's mineral production is reported. The Yearbook includes chapters devoted to each major mineral commodity produced in Canada: aluminum, coal, copper, diamonds, gold, iron ore, magnesium, nickel, potash, salt, silica, and uranium. The subject matter spans all stages of mineral industry activity from geoscience and exploration, through mining and processing, to markets and use. Although domestic issues receive the greatest attention in each chapter, international developments may also be reviewed because of the global nature of the mineral industry and the significant impact that such developments could have on the Canadian industry

  13. In vitro evaluation of iron solubility and dialyzability of various iron fortificants and of iron-fortified milk products targeted for infants and toddlers.

    Science.gov (United States)

    Kapsokefalou, Maria; Alexandropoulou, Isidora; Komaitis, Michail; Politis, Ioannis

    2005-06-01

    The objectives of the present study were: to compare the solubility and dialyzability of various iron fortificants (iron pyrophosphate, ferrous bis-glycinate, ferrous gluconate, ferrous lactate, ferrous sulfate) added, in the presence of ascorbic acid, to pasteurized milk samples produced under laboratory conditions; and to compare the solubility and dialyzability of iron in commercial pasteurized, UHT and condensed milk products available in the Greek market fortified with various vitamins and minerals including iron and targeted towards infants (6-12 months old) and toddlers. Iron solubility and dialyzability were determined using a simulated gastrointestinal digestive system. Ferrous dialyzable iron (molecular weight lower than 8000) was used as an index for prediction of iron bioavailability. Ferrous dialyzable iron in pasteurized milk samples fortified with iron pyrophosphate, ferrous lactate and ferrous bis-glycinate was higher (P iron in products fortified with ferrous lactate was not different (P > 0.05) from those fortified with ferrous sulfate. Ferrous dialyzable iron in four condensed commercial milk products was higher (P iron was higher (P iron source, milk processing and the overall product composition affect formation of ferrous dialyzable iron and may determine the success and effectiveness of iron fortification of milk.

  14. New french uranium mineral species

    International Nuclear Information System (INIS)

    Branche, G.; Chervet, J.; Guillemin, C.

    1952-01-01

    In this work, the authors study the french new uranium minerals: parsonsite and renardite, hydrated phosphates of lead and uranium; kasolite: silicate hydrated of uranium and lead uranopilite: sulphate of uranium hydrated; bayleyite: carbonate of uranium and of hydrated magnesium; β uranolite: silicate of uranium and of calcium hydrated. For all these minerals, the authors give the crystallographic, optic characters, and the quantitative chemical analyses. On the other hand, the following species, very rare in the french lodgings, didn't permit to do quantitative analyses. These are: the lanthinite: hydrated uranate oxide; the α uranotile: silicate of uranium and of calcium hydrated; the bassetite: uranium phosphate and of hydrated iron; the hosphuranylite: hydrated uranium phosphate; the becquerelite: hydrated uranium oxide; the curite: oxide of uranium and lead hydrated. Finally, the authors present at the end of this survey a primary mineral: the brannerite, complex of uranium titanate. (author) [fr

  15. Role of dust alkalinity in acid mobilization of iron

    Directory of Open Access Journals (Sweden)

    A. Ito

    2010-10-01

    Full Text Available Atmospheric processing of mineral aerosols by acid gases (e.g., SO2, HNO3, N2O5, and HCl may play a key role in the transformation of insoluble iron (Fe in the oxidized or ferric (III form to soluble forms (e.g., Fe(II, inorganic soluble species of Fe(III, and organic complexes of iron. On the other hand, mineral dust particles have a potential of neutralizing the acidic species due to the alkaline buffer ability of carbonate minerals (e.g., CaCO3 and MgCO3. Here we demonstrate the impact of dust alkalinity on the acid mobilization of iron in a three-dimensional aerosol chemistry transport model that includes a mineral dissolution scheme. In our model simulations, most of the alkaline dust minerals cannot be entirely consumed by inorganic acids during the transport across the North Pacific Ocean. As a result, the inclusion of alkaline compounds in aqueous chemistry substantially limits the iron dissolution during the long-range transport to the North Pacific Ocean: only a small fraction of iron (<0.2% dissolves from hematite in the coarse-mode dust aerosols with 0.45% soluble iron initially. On the other hand, a significant fraction of iron (1–2% dissolves in the fine-mode dust aerosols due to the acid mobilization of the iron-containing minerals externally mixed with carbonate minerals. Consequently, the model quantitatively reproduces higher iron solubility in smaller particles as suggested by measurements over the Pacific Ocean. It implies that the buffering effect of alkaline content in dust aerosols might help to explain the inverse relationship between aerosol iron solubility and particle size. We also demonstrate that the iron solubility is sensitive to the chemical specification of iron-containing minerals in dust. Compared with the dust sources, soluble iron from combustion sources contributes to a relatively marginal effect for deposition of soluble iron over the North

  16. Proteomics Core

    Data.gov (United States)

    Federal Laboratory Consortium — Proteomics Core is the central resource for mass spectrometry based proteomics within the NHLBI. The Core staff help collaborators design proteomics experiments in a...

  17. Effect of annealing process of iron powder on magnetic properties ...

    Indian Academy of Sciences (India)

    Administrator

    Abstract. Iron powder magnetic cores are used as soft magnetic rotors, in micro special motors such as BS brake motors, refrigerator compressor motors and brushless servo motors. Heat treatment of iron powder played an important role in the magnetic properties and loss of the motor cores. After the annealing process,.

  18. IRON DOME

    African Journals Online (AJOL)

    6 Israeli Navy 'First Arm of the Sea: The Successful Interception of the Iron Dome Rocket .... sky to destroy them whilst in flight to minimise civilian casualties. ..... Including The Moon and Celestial Bodies.53 Demeyere further emphasises the.

  19. Iron overdose

    Science.gov (United States)

    ... tracing) X-ray to detect and track iron tablets through the stomach and intestines Treatment may include: ... BF, St. Geme JW, Schor NF, eds. Nelson Textbook of Pediatrics . 20th ed. Philadelphia, PA: Elsevier; 2016: ...

  20. Trace mineral interactions during elevated calcium consumption

    International Nuclear Information System (INIS)

    Smith, K.T.; Luhrsen, K.R.

    1986-01-01

    Elevated calcium consumption is reported to affect trace mineral bioavailability. The authors examined this phenomenon in both single dose radio-label test meals and an eight week feeding trial in rats. In the single dose studies, human milk, cows milk, and various calcium sources were examined in relation to radio-iron and radio-zinc retention. 59 Fe retention was greater from human milk than cows milk. However, when the calcium content of human milk was adjusted (with CaHPO 4 or CaCO 3 ) to equal the level in cows milk, iron retention was depressed. Similarly, when calcium sources (CaCO 3 , CaHPO 4 , hydroxy-apatite, bone meal) were examined at different calcium:metal molar ratios, the degree of inhibition on metal retention varied. In general, phosphate salts were more inhibiting than carbonates. In the feeding trial, calcium was fed in diets at normal (0.5%) or elevated (1.5%) levels. Serum, liver, kidney, and bone trace mineral profiles were obtained. In general, most trace elements showed decreased levels in the tissues. Zinc and iron were most striking, followed by magnesium with minor changes in copper. A high calcium:high mineral supplemented group was also fed. Mixed mineral supplementation prevented all calcium interactions. These data indicate the importance of calcium mineral interactions in bioavailability considerations in both milk sources and in mineral supplementation

  1. Maxi- and mini-ferritins: minerals and protein nanocages.

    Science.gov (United States)

    Bevers, Loes E; Theil, Elizabeth C

    2011-01-01

    Ferritins synthesize ferric oxide biominerals and are central to all life for concentrating iron and protection against oxidative stress from the ferrous and oxidant chemistry. The ferritin protein nanocages and biomineral synthesis are discussed in terms of wide biological distribution of the maxi-ferritins (24 subunit ± heme) and mini-ferritins (Dps) (12 subunit), conservations of the iron/oxygen catalytic sites in the protein cages, mineral formation (step i. Fe(II) entry and binding, step ii. O(2) or H(2)O(2) binding and formation of transition intermediates, step iii. release of differric oxo mineral precursors from active sites, step iv. nucleation and mineralization) properties of the minerals, and protein control of mineral dissolution and release of Fe(II). Pores in ferritin protein cages control iron entry for mineralization and iron exit after mineral dissolution. The relationship between phosphate or the presence of catalytically inactive subunits (animal L subunits) and ferritin iron mineral disorder is developed based on new information about contributions of ferritin protein cage structure to nucleation in protein cage subunit channels that exit close enough to those of other subunits and exiting mineral nuclei to facilitate bulk mineral formation. How and where protons move in and out of the protein during mineral synthesis and dissolution, how ferritin cage assembly with 12 or 24 subunits is encoded in the widely divergent ferritin amino acid sequences, and what is the role of the protein in synthesis of the bulk mineral are all described as problems requiring new approaches in future investigations of ferritin biominerals.

  2. Metabolismo do ferro em suínos recebendo dietas contendo fitase, níveis reduzidos de fósforo inorgânico e sem suplemento micromineral e vitamínico Iron metabolism in swine fed phytase-added diets without mineral vitamin supplement and reduced inorganic phosphorus

    Directory of Open Access Journals (Sweden)

    Renzo Freire de Almeida

    2007-08-01

    Full Text Available O presente estudo foi desenvolvido com o objetivo de avaliar o metabolismo do ferro por meio da determinação do eritrograma, contagem de reticulócitos, dosagem de ferro sérico, ferritina sérica e transferrina sérica de suínos em fase de terminação alimentados com dietas contendo fitase, sem suplemento micromineral/vitamínico e redução dos níveis de fósforo inorgânico (Pi. Foram utilizadas 48 fêmeas suínas de linhagem comercial, com peso inicial de 60kg, distribuídas em seis tratamentos com oito animais em cada grupo. A colheita de sangue foi feita em um grupo de 24 animais com 100kg e em outro grupo de 24 animais com 120kg. Não foram observadas diferenças (P>0,05 nos valores obtidos do eritrograma, da contagem de reticulócitos, de ferro sérico e de transferrina para os animais nos tratamentos testados. Com relação à ferritina, verificou-se que os animais até os 100kg de peso vivo que receberam ração sem suplemento micromineral/vitamínico, sem fósforo inorgânico e com fitase apresentaram valores superiores (PThis research was aimed at evaluating the effect of mineral-vitamin supplement withdrawal associated to reduction of inorganic phosphorus level and addition of phytase in feed on iron metabolism of finishing-phase pigs. Erythrocyte and reticulocyte count, serum iron, ferritin and transferrin quantification was performed. Forty eight hybrid swine females with initial average weight of 60kg were allotted to a completely randomized experimental design with six with four replications of two animals each. Blood was drawn from a group of twenty four 100kg animals and from a second group of twenty four 120kg animals. No differences (P>0.05 were observed in erythrocyte and reticulocyte count or serum iron and transferrin quantification. However, ferritin levels were increased in 100kg animals fed basal feed without mineral/vitamin supplement and inorganic phosphorus with phytase when compared to animals fed basal feed

  3. Refining of the cracked products of mineral oils, etc

    Energy Technology Data Exchange (ETDEWEB)

    Seelig, S

    1928-06-02

    A process is disclosed for the refining of the distilled or cracked products from mineral oil, shale oil, or brown-coal-tar oil, with the aid of alkali-plumbite solution, characterized by adding to the plumbite solution from oxide, iron hydroxide, basic oxide, or an iron salt.

  4. Microbial processes in banded iron formation deposition

    DEFF Research Database (Denmark)

    Posth, Nicole; Konhauser, Kurt; Kappler, Andreas

    2013-01-01

    , remains unresolved. Evidence of an anoxic Earth with only localized oxic areas until the Great Oxidation Event ca 2·45 to 2·32 Ga makes the investigation of O2-independent mechanisms for banded iron formation deposition relevant. Recent studies have explored the long-standing proposition that Archean......Banded iron formations have been studied for decades, particularly regarding their potential as archives of the Precambrian environment. In spite of this effort, the mechanism of their deposition and, specifically, the role that microbes played in the precipitation of banded iron formation minerals...... banded iron formations may have been formed, and diagenetically modified, by anaerobic microbial metabolisms. These efforts encompass a wide array of approaches including isotope, ecophysiological and phylogeny studies, molecular and mineral marker analysis, and sedimentological reconstructions. Herein...

  5. A Mesoproterozoic iron formation

    Science.gov (United States)

    Canfield, Donald E.; Zhang, Shuichang; Wang, Huajian; Wang, Xiaomei; Zhao, Wenzhi; Su, Jin; Bjerrum, Christian J.; Haxen, Emma R.; Hammarlund, Emma U.

    2018-04-01

    We describe a 1,400 million-year old (Ma) iron formation (IF) from the Xiamaling Formation of the North China Craton. We estimate this IF to have contained at least 520 gigatons of authigenic Fe, comparable in size to many IFs of the Paleoproterozoic Era (2,500–1,600 Ma). Therefore, substantial IFs formed in the time window between 1,800 and 800 Ma, where they are generally believed to have been absent. The Xiamaling IF is of exceptionally low thermal maturity, allowing the preservation of organic biomarkers and an unprecedented view of iron-cycle dynamics during IF emplacement. We identify tetramethyl aryl isoprenoid (TMAI) biomarkers linked to anoxygenic photosynthetic bacteria and thus phototrophic Fe oxidation. Although we cannot rule out other pathways of Fe oxidation, iron and organic matter likely deposited to the sediment in a ratio similar to that expected for anoxygenic photosynthesis. Fe reduction was likely a dominant and efficient pathway of organic matter mineralization, as indicated by organic matter maturation by Rock Eval pyrolysis combined with carbon isotope analyses: Indeed, Fe reduction was seemingly as efficient as oxic respiration. Overall, this Mesoproterozoic-aged IF shows many similarities to Archean-aged (>2,500 Ma) banded IFs (BIFs), but with an exceptional state of preservation, allowing an unprecedented exploration of Fe-cycle dynamics in IF deposition.

  6. Hydrothermal minerals

    Digital Repository Service at National Institute of Oceanography (India)

    Nath, B.N.

    flux. Circulation of seawater through the oceanic crust and upper mantle gives rise to a complex series of physical and chemical reactions that lead to the 1) formation of seafloor mineral deposits; 2) alteration of oceanic crust; 3) control... temperature in the high-temperature reaction zone near the heat source. Important parameters in determining the high- temperature fluid composition are • pressure, • temperature, • water/rock ratio, • rock composition, • recharge fluid...

  7. The Effect of Pressure on Iron Speciation in Silicate Melts at a Fixed Oxygen Fugacity: The Possibility of a Redox Profile Through a Terrestrial Magma Ocean

    Science.gov (United States)

    Armstrong, K.; Frost, D. J.; McCammon, C. A.; Rubie, D. C.; Boffa Ballaran, T.

    2017-12-01

    As terrestrial planets accreted, mantle silicates equilibrated with core-forming metallic iron, which would have imposed a mantle oxygen fugacity below the iron-wüstite oxygen buffer. Throughout Earth's history, however, the oxygen fugacity of at least the accessible portions of the upper mantle has been 4-5 orders of magnitude higher. The process that caused the rapid increase in the redox state of the mantle soon after core formation is unclear. Here we test the possibility that pressure stabilises ferric iron in silicate melts, as has been observed in silicate minerals. A deep magma ocean, which would have likely existed towards the end of accretion, could then develop a gradient in oxygen fugacity for a fixed ferric-ferrous ratio as a result of pressure. We have equilibrated an andesitic melt with a Ru-RuO2 buffer in a multianvil press between 5 and 24 GPa. Further experiments were performed on the same melt in equilibrium with iron metal. The recovered melts were then analysed using Mössbauer spectroscopy to determine the ferric/ferrous ratio. The results show that for the Ru-RuO2 buffer at lower pressures, the ferric iron content decreases with pressure, due to a positive volume change of the reaction FeO + 1/4O2 = FeO1.5. Ferric iron content also appears to be sensitive to water content at lower pressures. However, above 15 GPa this trend apparently reverses and the ferric iron content increases with pressure. This reversal in pressure dependence would drive the oxygen fugacity of a deep magma ocean with a fixed ferric/ferrous ratio down with increasing depth. This would create a redox gradient, where the magma ocean could potentially be in equilibrium with metallic iron at its base but more oxidised in its shallower regions. Crystallisation of this magma ocean could render an upper mantle oxygen fugacity similar to that in the Earth's accessible mantle today.

  8. Uranyl adsorption at clay mineral surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Roesch, N. [Technische Univ. Muenchen (Germany). Fachgebiet Theoretische Chemie

    2016-11-01

    This first systematic survey of actinide adsorption at complex clay mineral surfaces, which provided new insights at the atomic level, is currently being extended to neptunyl NpO{sub 2}{sup +} and more complex minerals, like iron-substituted phyllosilicates. In this way we examine if the concepts developed so far can be applied more generally to support the interpretation of pertinent experiments. A further facet of these studies is to account also for the dynamic nature of the mineral/water interface by means of exemplary dynamic simulations.

  9. Influence of Atmospheric Processes on the Solubility and Composition of Iron in Saharan Dust.

    Science.gov (United States)

    Longo, Amelia F; Feng, Yan; Lai, Barry; Landing, William M; Shelley, Rachel U; Nenes, Athanasios; Mihalopoulos, Nikolaos; Violaki, Kalliopi; Ingall, Ellery D

    2016-07-05

    Aerosol iron was examined in Saharan dust plumes using a combination of iron near-edge X-ray absorption spectroscopy and wet-chemical techniques. Aerosol samples were collected at three sites located in the Mediterranean, the Atlantic, and Bermuda to characterize iron at different atmospheric transport lengths and time scales. Iron(III) oxides were a component of aerosols at all sampling sites and dominated the aerosol iron in Mediterranean samples. In Atlantic samples, iron(II and III) sulfate, iron(III) phosphate, and iron(II) silicates were also contributors to aerosol composition. With increased atmospheric transport time, iron(II) sulfates are found to become more abundant, aerosol iron oxidation state became more reduced, and aerosol acidity increased. Atmospheric processing including acidic reactions and photoreduction likely influence the form of iron minerals and oxidation state in Saharan dust aerosols and contribute to increases in aerosol-iron solubility.

  10. 中国原料矿产保障体制革新论——以钾、铁矿生产与贸易实践的比较为例证%Research on innovation of China raw mineral security system —an example of comparison of production and trade ketween iron deposit and potassium deposit

    Institute of Scientific and Technical Information of China (English)

    袁华江

    2012-01-01

    The supply and security of mineral raw materials is directly related to China's industrial and agricultural development, stability and efficiency, it plays an important role in the national economy. A large number of mineral raw materials in China can not be completely self-sufficient,and there is a great dependence on foreign mineral raw materials. How to re-construct our country's security system of mineral raw materials in the international and domestic markets is becoming increasingly important role in economic and strategic significance. On comparison of potassium and iron ore mine in mineral development and trade practice.it is concluded that: improving the foreign investment mode, innovative financial and credit measures, improving the existing tax burden on mineral raw materials enterprises,the implementation of development model that scale development in exploration and mining,is a realistic choice for the current resource strategy.%原料矿产的供给与保障直接关系到我国工农业生产的稳定与效率,对于国民经济的发展极为重要.而今我国一些重要的原料矿产不能完全自给,对外依存度较大.如何在国际国内两个市场重新构筑我国原料矿产的保障体制日显经济与战略意义.通过对钾盐矿、铁矿两大基本原料矿产的生产与贸易实践的比较可发现:完善境外投资方式、创新金融信贷措施、改善原料矿产企业的现存财税负担、推行原料矿产勘采规模化和产业一体化发展模式是当前资源战略的现实选择.

  11. Cytosolic iron chaperones: Proteins delivering iron cofactors in the cytosol of mammalian cells.

    Science.gov (United States)

    Philpott, Caroline C; Ryu, Moon-Suhn; Frey, Avery; Patel, Sarju

    2017-08-04

    Eukaryotic cells contain hundreds of metalloproteins that are supported by intracellular systems coordinating the uptake and distribution of metal cofactors. Iron cofactors include heme, iron-sulfur clusters, and simple iron ions. Poly(rC)-binding proteins are multifunctional adaptors that serve as iron ion chaperones in the cytosolic/nuclear compartment, binding iron at import and delivering it to enzymes, for storage (ferritin) and export (ferroportin). Ferritin iron is mobilized by autophagy through the cargo receptor, nuclear co-activator 4. The monothiol glutaredoxin Glrx3 and BolA2 function as a [2Fe-2S] chaperone complex. These proteins form a core system of cytosolic iron cofactor chaperones in mammalian cells. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  12. Sulfur Cycling in an Iron Oxide-Dominated, Dynamic Marine Depositional System: The Argentine Continental Margin

    Directory of Open Access Journals (Sweden)

    Natascha Riedinger

    2017-05-01

    Full Text Available The interplay between sediment deposition patterns, organic matter type and the quantity and quality of reactive mineral phases determines the accumulation, speciation, and isotope composition of pore water and solid phase sulfur constituents in marine sediments. Here, we present the sulfur geochemistry of siliciclastic sediments from two sites along the Argentine continental slope—a system characterized by dynamic deposition and reworking, which result in non-steady state conditions. The two investigated sites have different depositional histories but have in common that reactive iron phases are abundant and that organic matter is refractory—conditions that result in low organoclastic sulfate reduction rates (SRR. Deposition of reworked, isotopically light pyrite and sulfurized organic matter appear to be important contributors to the sulfur inventory, with only minor addition of pyrite from organoclastic sulfate reduction above the sulfate-methane transition (SMT. Pore-water sulfide is limited to a narrow zone at the SMT. The core of that zone is dominated by pyrite accumulation. Iron monosulfide and elemental sulfur accumulate above and below this zone. Iron monosulfide precipitation is driven by the reaction of low amounts of hydrogen sulfide with ferrous iron and is in competition with the oxidation of sulfide by iron (oxyhydroxides to form elemental sulfur. The intervals marked by precipitation of intermediate sulfur phases at the margin of the zone with free sulfide are bordered by two distinct peaks in total organic sulfur (TOS. Organic matter sulfurization appears to precede pyrite formation in the iron-dominated margins of the sulfide zone, potentially linked to the presence of polysulfides formed by reaction between dissolved sulfide and elemental sulfur. Thus, SMTs can be hotspots for organic matter sulfurization in sulfide-limited, reactive iron-rich marine sedimentary systems. Furthermore, existence of elemental sulfur and iron

  13. Serum levels of iron in Sør-Varanger, Northern Norway--an iron mining municipality.

    Science.gov (United States)

    Broderstad, Ann R; Smith-Sivertsen, Tone; Dahl, Inger Marie S; Ingebretsen, Ole Christian; Lund, Eiliv

    2006-12-01

    The purpose of this study was to investigate iron status in a population with a high proportion of miners in the northernmost part of Norway. Cross-sectional, population-based study performed in order to investigate possible health effects of pollution in the population living on both sides of the Norwegian-Russian border. All individuals living in the community of Sør-Varanger were invited for screening in 1994. In 2000, blood samples from 2949 participants (response rate 66.8 %), age range 30-69 years, were defrosted. S-ferritin and transferrin saturation were analysed in samples from 1548 women and 1401 men. About 30 % (n = 893) were employed in the iron mining industry, 476 of whom were miners and 417 had other tasks in the company. Type and duration of employment and time since last day of work at the company were used as indicators of exposure. Both s-ferritin levels and transferrin saturation were higher in men than in women. S-ferritin increased with increasing age in women, while the opposite was true for men. Iron deficiency occurred with higher frequencies in women (16 %) than in men (4 %). Iron overload was uncommon in both sexes. Adjustment for smoking and self-reported pulmonary diseases did not show any effect on iron levels. Miners had non-significant higher mean s-ferritin and transferrin saturation than non-miners. Neither duration, nor time since employment in the mine, had any impact on iron status. Our analyses did not show any associations between being a miner in the iron mining industry and serum iron levels compared to the general population.

  14. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... iron-rich foods, especially during certain stages of life when more iron is needed, such as childhood and pregnancy. Good sources of iron are meat, poultry, fish, and iron- ...

  15. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... that are good sources of iron include dried beans, dried fruits, eggs, lean red meat, salmon, iron- ... of iron, including iron-fortified breads and cereals, beans, tofu, dried fruits, and spinach and other dark ...

  16. Iron in diet

    Science.gov (United States)

    ... Reasonable amounts of iron are also found in lamb, pork, and shellfish. Iron from vegetables, fruits, grains, ... strawberries, tomatoes, and potatoes) also increase iron absorption. Cooking foods in a cast-iron skillet can also ...

  17. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... from developing iron-deficiency anemia. Foods that are good sources of iron include dried beans, dried fruits, ... iron is needed, such as childhood and pregnancy. Good sources of iron are meat, poultry, fish, and ...

  18. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... you are diagnosed with iron-deficiency anemia. Risk Factors You may have an increased risk for iron- ... iron-deficiency anemia if you have certain risk factors , including pregnancy. To prevent iron-deficiency anemia, your ...

  19. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... for your body to absorb iron from the gastrointestinal tract (GI tract). Blood loss When you lose blood, ... iron deficiency. Endurance athletes lose iron through their gastrointestinal tracts. They also lose iron through the breakdown of ...

  20. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... iron in your body is low. For this reason, other iron tests are also done. Ferritin measure ... iron is needed, such as childhood and pregnancy. Good sources of iron are meat, poultry, fish, and ...

  1. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... develop new therapies for conditions that affect the balance of iron in the body and lead to ... Disease Control and Prevention) Iron - Health Professional Fact Sheet (NIH) Iron Dietary Supplement Fact Sheet (NIH) Iron- ...

  2. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... to moderate iron-deficiency anemia, or red blood cell transfusion for severe iron-deficiency anemia. You may ... body needs iron to make healthy red blood cells. Iron-deficiency anemia usually develops over time because ...

  3. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... enough iron-rich foods, such as meat and fish, may result in you getting less than the ... pregnancy. Good sources of iron are meat, poultry, fish, and iron-fortified foods that have iron added. ...

  4. Iron Dextran Injection

    Science.gov (United States)

    Iron dextran injection is used to treat iron-deficiency anemia (a lower than normal number of red blood cells ... treated with iron supplements taken by mouth. Iron dextran injection is in a class of medications called ...

  5. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... and severity. Treatments may include iron supplements, procedures, surgery, and dietary ... iron supplements, also called iron pills or oral iron, by mouth once or several times a ...

  6. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... developing iron-deficiency anemia. Foods that are good sources of iron include dried beans, dried fruits, eggs, ... is needed, such as childhood and pregnancy. Good sources of iron are meat, poultry, fish, and iron- ...

  7. Iron deficiency

    DEFF Research Database (Denmark)

    Schou, Morten; Bosselmann, Helle; Gaborit, Freja

    2015-01-01

    BACKGROUND: Both iron deficiency (ID) and cardiovascular biomarkers are associated with a poor outcome in heart failure (HF). The relationship between different cardiovascular biomarkers and ID is unknown, and the true prevalence of ID in an outpatient HF clinic is probably overlooked. OBJECTIVES.......043). CONCLUSION: ID is frequent in an outpatient HF clinic. ID is not associated with cardiovascular biomarkers after adjustment for traditional confounders. Inflammation, but not neurohormonal activation is associated with ID in systolic HF. Further studies are needed to understand iron metabolism in elderly HF...

  8. Primordial Noble Gases from Earth's Core

    Science.gov (United States)

    Wang, K.; Lu, X.; Brodholt, J. P.

    2016-12-01

    Recent partitioning experiment suggests helium is more compatible in iron melt than in molten silicates at high pressures (> 10 GPa) (1), thus provide the possibility of the core as being the primordial noble gases warehouse that is responsible for the high primordial/radiogenic noble gas isotopic ratios observed in plume-related basalts. However, the possible transportation mechanism of the noble gases from the core to the overlying mantle is still ambiguous, understanding how this process would affect the noble gas isotopic characteristics of the mantle is critical to validate this core reservoir model. As diffusion is a dominant mass transport process that plays an important role in chemical exchange at the core-mantle boundary (CMB), we have determined the diffusion coefficients of helium, neon and argon in major lower mantle minerals, i.e. periclase (MgO), bridgemanite (MgSiO3-Pv) and post-perovskite (MgSiO3-PPv), by first-principles calculation based on density functional theory (DFT). As expected, the diffusion rate of helium is the fastest at the CMB, which is in the range of 3 × 10-10 to 1 × 10-8 m2/s. The neon diffusion is slightly slower, from 5 × 10-10 to 5 × 10-9 m2/s. Argon diffuses slowest at the rate from 1 × 10-10 to 2 × 10-10 m2/s. We have further simulated the evolution of noble gas isotopic ratios in the mantle near the CMB. Considering its close relationship with the mantle plumes and very likely to be the direct source of "hot-spot" basalts, we took a close investigation on the large low-shear-velocity provinces (LLSVPs). Under reasonable assumptions based on our diffusion parameters, the modelling results indicate that LLSVP is capable of generating all the noble gas isotope signals, e.g., 3He/4He = 55 Ra, 3He/22Ne = 3.1, 3He/36Ar = 0.82, 40Ar/36Ar = 9500, that are in good agreement with the observed values in "hot-spot" basalts (2). Therefore, this core-reservior hypothesis is a self-consistent model that can fits in multiple noble gas

  9. Overview of Minerals

    Science.gov (United States)

    ... content of local soil) Required for the formation of thyroid hormones 150 micrograms 1,100 micrograms Iron As heme iron: Beef, poultry, fish, kidneys, and liver As nonheme iron: Soybean flour, beans, molasses, spinach, clams, and fortified grains and ...

  10. Characterization of tetraethylene glycol passivated iron nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Nunes, Eloiza da Silva; Viali, Wesley Renato [Laboratório de Materiais Magnéticos e Coloides, Departamento de Físico-química, Instituto de Química, Universidade Estadual Paulista, Araraquara, SP 14801-970 (Brazil); Silva, Sebastião William da; Coaquira, José Antonio Huamaní; Garg, Vijayendra Kumar; Oliveira, Aderbal Carlos de [Instituto de Física, Núcleo de Física Aplicada, Universidade de Brasília, Brasília, DF 70910-900 (Brazil); Morais, Paulo César [Instituto de Física, Núcleo de Física Aplicada, Universidade de Brasília, Brasília, DF 70910-900 (Brazil); School of Automation, Huazhong University of Science and Technology, Wuhan 430074 (China); Jafelicci Júnior, Miguel, E-mail: jafeli@iq.unesp.br [Laboratório de Materiais Magnéticos e Coloides, Departamento de Físico-química, Instituto de Química, Universidade Estadual Paulista, Araraquara, SP 14801-970 (Brazil)

    2014-10-01

    Graphical abstract: - Highlights: • Metallic iron nanoparticles were passivated in tetraethylene glycol media. • Passivated nanoparticles presented pomegranate-like core@shell structure. • Passivation of metallic iron correlates with the tetraethylene glycol degradation. • Boron enriched metallic iron phase was more susceptible to oxidation. • The iron oxide shell was identified as Fe{sub 3}O{sub 4} with a mass fraction of 43:53 related to αFe. - Abstract: The present study describes the synthesis and characterization of iron@iron oxide nanoparticles produced by passivation of metallic iron in tetraethylene glycol media. Structural and chemical characterizations were performed using transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Mössbauer spectroscopy. Pomegranate-like core@shell nanoparticulate material in the size range of 90–120 nm was obtained. According to quantitative phase analysis using Rietveld structure refinement the synthesized iron oxide was identified as magnetite (Fe{sub 3}O{sub 4}) whereas the iron to magnetite mass fractions was found to be 47:53. These findings are in good agreement with the data obtained from Mössbauer and thermal gravimetric analysis (TGA). The XPS data revealed the presence of a surface organic layer with higher hydrocarbon content, possibly due to the tetraethylene glycol thermal degradation correlated with iron oxidation. The room-temperature (300 K) saturation magnetization measured for the as-synthesized iron and for the iron–iron oxide were 145 emu g{sup −1} and 131 emu g{sup −1}, respectively. The measured saturation magnetizations are in good agreement with data obtained from TEM, XRD and Mössbauer spectroscopy.

  11. Characterization of tetraethylene glycol passivated iron nanoparticles

    International Nuclear Information System (INIS)

    Nunes, Eloiza da Silva; Viali, Wesley Renato; Silva, Sebastião William da; Coaquira, José Antonio Huamaní; Garg, Vijayendra Kumar; Oliveira, Aderbal Carlos de; Morais, Paulo César; Jafelicci Júnior, Miguel

    2014-01-01

    Graphical abstract: - Highlights: • Metallic iron nanoparticles were passivated in tetraethylene glycol media. • Passivated nanoparticles presented pomegranate-like core@shell structure. • Passivation of metallic iron correlates with the tetraethylene glycol degradation. • Boron enriched metallic iron phase was more susceptible to oxidation. • The iron oxide shell was identified as Fe 3 O 4 with a mass fraction of 43:53 related to αFe. - Abstract: The present study describes the synthesis and characterization of iron@iron oxide nanoparticles produced by passivation of metallic iron in tetraethylene glycol media. Structural and chemical characterizations were performed using transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Mössbauer spectroscopy. Pomegranate-like core@shell nanoparticulate material in the size range of 90–120 nm was obtained. According to quantitative phase analysis using Rietveld structure refinement the synthesized iron oxide was identified as magnetite (Fe 3 O 4 ) whereas the iron to magnetite mass fractions was found to be 47:53. These findings are in good agreement with the data obtained from Mössbauer and thermal gravimetric analysis (TGA). The XPS data revealed the presence of a surface organic layer with higher hydrocarbon content, possibly due to the tetraethylene glycol thermal degradation correlated with iron oxidation. The room-temperature (300 K) saturation magnetization measured for the as-synthesized iron and for the iron–iron oxide were 145 emu g −1 and 131 emu g −1 , respectively. The measured saturation magnetizations are in good agreement with data obtained from TEM, XRD and Mössbauer spectroscopy

  12. Iron isotope systematics of the Skaergaard intrusion

    DEFF Research Database (Denmark)

    Lesher, Charles; Lundstrom, C.C.; Barfod, Gry

    crystallization on non-traditional stable isotope systems, particularly iron. FeTi oxide minerals (titanomagnetite and ilmenite) appear after ~60% of the magma had solidified. This was a significant event affecting the liquid line of descent and potentially accompanied by iron isotope fractionation. Here we...... report the results of a broad study of the iron isotope compositions of gabbros within the layered and upper border series of the Skaergaard intrusion, pegmatite and granophyre associated with these gabbroic rocks, and the sandwich horizon thought to represent the product of extreme differentiation and...

  13. Characterization and structural properties of iron in plants.

    Science.gov (United States)

    Dewanamuni, Udya; Dehipawala, Sunil; Gafney, Harry

    Iron is one of the most abundant metals in the soil and occurs in a wide range of chemical forms. Humans receive iron through either meat products or plants. Non meat eaters depend on plant product for their daily iron requirement. The iron absorption by plants depends on other minerals present in the soil and soil pH value. The amount of iron present in plants grown with different soil compositions were investigated using X-ray absorption spectroscopy (XAS) and Mossbauer spectroscopy. Based on the X-ray absorption data, the amount of iron in plants vary significantly with soil pH value. The Mossbauer spectroscopy reveals that iron present in the samples has the form Fe3+ or electron density at the site of the iron nucleus similar to that of Fe3+. CUNY Research Scholar Program, MSEIP.

  14. Core Characteristics Deterioration due to Plastic Deformation

    Science.gov (United States)

    Kaido, Chikara; Arai, Satoshi

    This paper discusses the effect of plastic deformation at core manufacturing on the characteristics of cores where non-oriented electrical steel sheets are used as core material. Exciting field and iron loss increase proportionally to plastic deformation in the case of rPeddy currents increase because plastic deformations of crystalline grains are distributed and then the flux distribution is induced. In the case of rP>20, the deterioration tend to saturate, and the increases in magnetic field and iron loss are 1000 to 1500A/m and 2 to 4W/kg. They are related to grain size, and high grade with larger grain may have lager field increase and smaller iron loss increase. Anomalous eddy current losses scarcely increase in this region. In actual motors, the plastic deformation affects iron loss increase although exciting current increases a little.

  15. Comparison of the mineralogy of the Boss-Bixby, Missouri copper-iron deposit, and the Olympic Dam copper-uranium-gold deposit, South Australia

    International Nuclear Information System (INIS)

    Brandom, R.T.; Hagni, R.D.; Allen, C.R.

    1985-01-01

    An ore microscopic examination of 80 polished sections prepared from selected drill core specimens from the Boss-Bixby, Missouri copper-iron deposit has shown that its mineral assemblage is similar to that of the Olympic Dam (Roxby Downs) copper-uranium-gold deposit in South Australia. A comparison with the mineralogy reported for Olympic Dam shows that both deposits contain: 1) the principal minerals, magnetite, hematite, chalcopyrite, and bornite, 2) the cobalt-bearing phases, carrollite and cobaltian pyrite, 3) the titanium oxides, rutile and anatase, 4) smaller amounts of martite, covellite, and electrum, 5) fluorite and carbonates, and 6) some alteration minerals. The deposits also are similar with regard to the sequence of mineral deposition: 1) early oxides, 2) then sulfide minerals, and 3) a final oxide generation. The deposits, however, are dissimilar with regard to their host rock lithologies and structural settings. The Boss-Bixby ores occupy breccia zones within a hydrothermally altered basic intrusive and intruded silicic volcanics, whereas the Olympic Dam ores are contained in sedimentary breccias in a graben or trough. Also, some minerals have been found thus far to occur at only one of the deposits. The similarity of mineralogy in these deposits suggests that they were formed from ore fluids that had some similarities in character and that the St. Francois terrane of Missouri is an important region for further exploration for deposits with this mineral assemblage

  16. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... Research Home / < Back To Health Topics / Iron-Deficiency Anemia Iron-Deficiency Anemia Also known as Leer en español Iron-deficiency ... iron-deficiency anemia. Blood tests to screen for iron-deficiency anemia To screen for iron-deficiency anemia, your doctor ...

  17. Mineral Facilities of Latin America and Canada

    Science.gov (United States)

    Bernstein, Rachel; Eros, Mike; Quintana-Velazquez, Meliany

    2006-01-01

    This data set consists of records for over 900 mineral facilities in Latin America and Canada. The mineral facilities include mines, plants, smelters, or refineries of aluminum, cement, coal, copper, diamond, gold, iron and steel, nickel, platinum-group metals, salt, and silver, among others. Records include attributes such as commodity, country, location, company name, facility type and capacity if applicable, and generalized coordinates. The data were compiled from multiple sources, including the 2003 and 2004 USGS Minerals Yearbooks (Latin America and Candada volume), data to be published in the 2005 Minerals Yearbook Latin America and Canada Volume, minerals statistics and information from the USGS minerals information Web site (minerals.usgs.gov/minerals), and data collected by USGS minerals information country specialists. Data reflect the most recent published table of industry structure for each country. Other sources include statistical publications of individual countries, annual reports and press releases of operating companies,and trade journals. Due to the sensitivity of some energy commodity data, the quality of these data should be evaluated on a country-by-country basis. Additional information and explanation is available from the country specialists.

  18. Iron and iron derived radicals

    International Nuclear Information System (INIS)

    Borg, D.C.; Schaich, K.M.

    1987-04-01

    We have discussed some reactions of iron and iron-derived oxygen radicals that may be important in the production or treatment of tissue injury. Our conclusions challenge, to some extent, the usual lines of thought in this field of research. Insofar as they are born out by subsequent developments, the lessons they teach are two: Think fast! Think small! In other words, think of the many fast reactions that can rapidly alter the production and fate of highly reactive intermediates, and when considering the impact of competitive reactions on such species, think how they affect the microenvironment (on the molecular scale) ''seen'' by each reactive molecule. 21 refs., 3 figs., 1 tab

  19. A uranium core for the Earth

    International Nuclear Information System (INIS)

    Rouat, S.

    2003-01-01

    According to the theory of M. Herndon, a US independent geophysicist, the center of the Earth's core should be made of a uranium sphere of about 8 km of diameter. This natural reactor, or 'geo-reactor', should be at the origin of the internal heat and of the magnetic field of the Earth. M. Herndon has extended his theory to the other planets of the solar system. This theory contradicts the one adopted since the 1940's by the community of geophysicists and which involves a crystallized iron and nickel internal core inside a liquid iron external core. Herndon's theory can explain also the geomagnetic field reversals. (J.S.)

  20. KeyPathwayMinerWeb

    DEFF Research Database (Denmark)

    List, Markus; Alcaraz, Nicolas; Dissing-Hansen, Martin

    2016-01-01

    , for instance), KeyPathwayMiner extracts connected sub-networks containing a high number of active or differentially regulated genes (proteins, metabolites) in the molecular profiles. The web interface at (http://keypathwayminer.compbio.sdu.dk) implements all core functionalities of the KeyPathwayMiner tool set......We present KeyPathwayMinerWeb, the first online platform for de novo pathway enrichment analysis directly in the browser. Given a biological interaction network (e.g. protein-protein interactions) and a series of molecular profiles derived from one or multiple OMICS studies (gene expression...... such as data integration, input of background knowledge, batch runs for parameter optimization and visualization of extracted pathways. In addition to an intuitive web interface, we also implemented a RESTful API that now enables other online developers to integrate network enrichment as a web service...

  1. A mesoproterozoic iron formation

    DEFF Research Database (Denmark)

    Canfield, Donald E; Zhang, Shuichang; Wang, Huajian

    2018-01-01

    formed in the time window between 1,800 and 800 Ma, where they are generally believed to have been absent. The Xiamaling IF is of exceptionally low thermal maturity, allowing the preservation of organic biomarkers and an unprecedented view of iron-cycle dynamics during IF emplacement. We identify....... Fe reduction was likely a dominant and efficient pathway of organic matter mineralization, as indicated by organic matter maturation by Rock Eval pyrolysis combined with carbon isotope analyses: Indeed, Fe reduction was seemingly as efficient as oxic respiration. Overall, this Mesoproterozoic......-aged IF shows many similarities to Archean-aged (>2,500 Ma) banded IFs (BIFs), but with an exceptional state of preservation, allowing an unprecedented exploration of Fe-cycle dynamics in IF deposition....

  2. Use of spectral data for estimating the relationship between iron oxides and 2:1 minerals with their respective reflectancesUso de dados espectrais para estimar a relação entre óxidos de ferro e minerais 2:1 com suas respectivas reflectâncias

    Directory of Open Access Journals (Sweden)

    Everson Cezar

    2013-09-01

    Full Text Available Iron oxides and 2:1 minerals have a strong influence on the spectral behavior of soils. However, studies that address more deeply the relationship between them and their reflectances are scarce. Thus, the objective of this study was to estimate the relationship between iron oxides and 2:1 minerals with their reflectance factors, and assess whether such a relationship presents a linear behavior. The experimental design was completely randomized with four replicates per treatment. The spectral readings of the samples of hematite, goethite, magnetite and bentonite were performed using the equipment FieldSpec jr 3, which covers the spectral range from 350 to 2500 nm. After the readings, were chosen the intervals that best represented the minerals and performed statistical analysis from the average reflectance factors found in these points. The results showed that the hematite, goethite and magnetite have nonlinear relationship with their reflectance factors, while bentonite has not only linear relationship in the range studied, but in the entire area covered by the equipment. Thus, we conclude that relatively small amounts of iron oxides are able to affect soil reflectance in the same way that amounts close to 100%. With respect to mineral 2:1 concludes that the increase in the proportion of them in a certain class of soil leads to a progressive decrease of the reflectance factor across the entire spectrum-optical, as described for other elements. Os óxidos de ferro e os minerais 2:1 possuem forte influência sobre o comportamento espectral dos solos. No entanto, estudos que abordem de maneira mais profunda a relação entre ambos e suas respectivas reflectâncias são escassos. Desta forma, o objetivo deste trabalho foi de estimar a relação entre óxidos de ferro e minerais 2:1 com seus respectivos fatores de reflectância, e avaliar se tal relação apresenta comportamento linear. O delineamento utilizado foi inteiramente casualizado com 4

  3. Tropical forest soil microbial communities couple iron and carbon biogeochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Dubinsky, E.A.; Silver, W.L.; Firestone, M.K.

    2009-10-15

    We report that iron-reducing bacteria are primary mediators of anaerobic carbon oxidation in upland tropical soils spanning a rainfall gradient (3500 - 5000 mm yr-1) in northeast Puerto Rico. The abundant rainfall and high net primary productivity of these tropical forests provide optimal soil habitat for iron-reducing and iron-oxidizing bacteria. Spatially and temporally dynamic redox conditions make iron-transforming microbial communities central to the belowground carbon cycle in these wet tropical forests. The exceedingly high abundance of iron-reducing bacteria (up to 1.2 x 10{sup 9} cells per gram soil) indicated that they possess extensive metabolic capacity to catalyze the reduction of iron minerals. In soils from the higher rainfall sites, measured rates of ferric iron reduction could account for up to 44 % of organic carbon oxidation. Iron reducers appeared to compete with methanogens when labile carbon availability was limited. We found large numbers of bacteria that oxidize reduced iron at sites with high rates of iron reduction and large numbers of iron-reducers. the coexistence of large populations of ironreducing and iron-oxidizing bacteria is evidence for rapid iron cycling between its reduced and oxidized states, and suggests that mutualistic interactions among these bacteria ultimately fuel organic carbon oxidation and inhibit CH4 production in these upland tropical forests.

  4. Microanalysis of iron oxidation state in iron oxides using X Ray Absorption Near Edge Structure (XANES)

    Science.gov (United States)

    Sutton, S. R.; Delaney, J.; Bajt, S.; Rivers, M. L.; Smith, J. V.

    1993-01-01

    An exploratory application of x ray absorption near edge structure (XANES) analysis using the synchrotron x ray microprobe was undertaken to obtain Fe XANES spectra on individual sub-millimeter grains in conventional polished sections. The experiments concentrated on determinations of Fe valence in a suite of iron oxide minerals for which independent estimates of the iron speciation could be made by electron microprobe analysis and x ray diffraction.

  5. Inorganic and organic trace mineral supplementation in weanling pig diets

    Directory of Open Access Journals (Sweden)

    MARIA C. THOMAZ

    2015-06-01

    Full Text Available A study was conducted to evaluate the effects of dietary inorganic and organic trace minerals in two levels of supplementation regarding performance, diarrhea occurrence, hematological parameters, fecal mineral excretion and mineral retention in metacarpals and liver of weanling pigs. Seventy piglets weaned at 21 days of age with an average initial body weight of 6.70 ± 0.38 kg were allotted in five treatments: control diet (no added trace mineral premix; 50% ITMP (control diet with inorganic trace mineral premix supplying only 50% of trace mineral requirements; 50% OTMP (control diet with organic trace mineral premix supplying only 50% of trace mineral requirements; 100% ITMP (control diet with inorganic trace mineral premix supplying 100% of trace mineral requirements; and 100% OTMP (control diet with organic trace mineral premix supplying 100% of trace mineral requirements. Feed intake and daily weight gain were not affected by treatments, however, piglets supplemented by trace minerals presented better gain:feed ratio. No differences were observed at calcium, phosphorus, potassium, magnesium, sodium and sulfur excreted in feces per kilogram of feed intake. Treatments did not affect calcium, phosphorus, magnesium, sulfur and iron content in metacarpals. Trace mineral supplementation, regardless of level and source, improved the performance of piglets.

  6. Iron addition to soil specifically stabilized lignin

    Science.gov (United States)

    Steven J. Hall; Whendee L. Silver; Vitaliy I. Timokhin; Kenneth E. Hammel

    2016-01-01

    The importance of lignin as a recalcitrant constituent of soil organic matter (SOM) remains contested. Associations with iron (Fe) oxides have been proposed to specifically protect lignin from decomposition, but impacts of Fe-lignin interactions on mineralization rates remain unclear. Oxygen (O2) fluctuations characteristic of humid tropical...

  7. Radon risk in ore miners

    International Nuclear Information System (INIS)

    Beno, M.

    1997-01-01

    Underground workers are exposed to various clastogenic agents. One of these agents, radon, attracts attention of recent research as it causes lung cancer in the population occupationally exposed to its various concentrations especially in mine air of uranium mines or ore mines. This paper is a pilot study in which the numbers of chromosomal aberrations (CA) in lymphocytes of ore mines (Nizna Slana-iron ore, Hnusta-talc ore) located in east central Slovakia were followed and related to the lifetime underground radon exposure and to lifetime smoking. Seventy miners volunteering after an informed consent served as donors of venous blood. Twenty healthy pro-bands, age matched with the miners, which never worked underground (mostly clerks) served as donors of control blood samples. The exposure to radon and smoking has been estimated according to working-records and personal anamnesis. The findings unequivocally showed a small but statistically significant clastogenic effect of the exposure to underground environment of the mines concerned. This study has shown also a small but significant influence of smoking, which in the subgroup of miners working underground less than 1500 shifts may have acted synergically with the underground exposure. It was concluded tat: (1) Significantly higher counts of chromosomal aberrations in lymphocytes of 70 miners than in an age matched control group of 20 white-collar workers were found; (2) The higher counts of chromosomal aberrations could be ascribed to underground exposure of miners and to smoking; (3) The positive dependence of the number of chromosomal aberrations from the exposure to smoking was loose and it was expressed by significantly higher chromosomal aberrations counts in the group of miners working less than 1500 shifts underground; (4) A dependence of chromosomal aberrations counts from the exposure to radon could not be assessed. At relatively low numbers of pro-bands in subgroups it was not ruled out the confounding

  8. Minerals Industry' 97. Survey report

    International Nuclear Information System (INIS)

    1997-01-01

    The aim of this annual survey is to provide timely and accurate financial data such as production, price movements, profitability, distribution of assets by activity, employment and labour cost and taxation on the Australian minerals industry. It aims to facilitate more informed debate on the industry's role and importance in the economy. The report also includes information on the safety and health performance and overseas exploration expenditure of the minerals industry. This twenty-first survey relates to the year ended 30 June 1997. The proportion of activity covered in this year's survey is comparable with the 1996 survey. The mineral industry is defined as including exploration for, extraction and primary processing of minerals in Australia. The oil, gas, iron and steel industries are excluded. As for the uranium industry, increased mine capacity over the medium term saw a switch away from spot market purchases to long term contracts for uranium in 1996. This, coupled with announced releases from the US stockpile, saw downward pressure on spot market prices for uranium during 1996/97. The average spot market price for U 3 O 8 fell by an average of 6 percent during 1996/97 and was approximately 16 percent lower than three years ago. General uncertainty over the future profitability of coal industry is compounded by the likely softness of future coal prices

  9. Reactivity of Uranium and Ferrous Iron with Natural Iron Oxyhydroxides.

    Science.gov (United States)

    Stewart, Brandy D; Cismasu, A Cristina; Williams, Kenneth H; Peyton, Brent M; Nico, Peter S

    2015-09-01

    Determining key reaction pathways involving uranium and iron oxyhydroxides under oxic and anoxic conditions is essential for understanding uranium mobility as well as other iron oxyhydroxide mediated processes, particularly near redox boundaries where redox conditions change rapidly in time and space. Here we examine the reactivity of a ferrihydrite-rich sediment from a surface seep adjacent to a redox boundary at the Rifle, Colorado field site. Iron(II)-sediment incubation experiments indicate that the natural ferrihydrite fraction of the sediment is not susceptible to reductive transformation under conditions that trigger significant mineralogical transformations of synthetic ferrihydrite. No measurable Fe(II)-promoted transformation was observed when the Rifle sediment was exposed to 30 mM Fe(II) for up to 2 weeks. Incubation of the Rifle sediment with 3 mM Fe(II) and 0.2 mM U(VI) for 15 days shows no measurable incorporation of U(VI) into the mineral structure or reduction of U(VI) to U(IV). Results indicate a significantly decreased reactivity of naturally occurring Fe oxyhydroxides as compared to synthetic minerals, likely due to the association of impurities (e.g., Si, organic matter), with implications for the mobility and bioavailability of uranium and other associated species in field environments.

  10. Moessbauer and positron annihilation studies of microstructural peculiarities of iron-dextran complexes

    International Nuclear Information System (INIS)

    Oshtrakh, M.I.; Kopelyan, E.A.; Semionkin, V.A.; Livshits, A.B.; Kozlov, A.A.

    1995-01-01

    The microstructural peculiarities of pharmaceutically important iron-dextran complexes were studied by Moessbauer and positron annihilation techniques. The results of Moessbauer spectroscopy showed variations of the iron cores in iron-dextran complexes containing different forms of FeOOH and different electronic and magnetic states of iron. The results of angular correlations of annihilation radiation and positron life-time spectroscopies showed microstructural variations of the dextran shell of the iron-dextran complexes. (author) 19 refs.; 4 tabs

  11. Perencanaan Strategik SBU Mineral PT Sucofindo (Persero

    Directory of Open Access Journals (Sweden)

    Suprapto Suprapto

    2017-05-01

    Full Text Available Strategic planning requires an organization in the face of today's business competition and a more complex future. Likewise, Mineral Gas Station also requires this strategic planning as a newly formed business unit of 2015. Therefore, the company analyzed its internal and external factors as well as a future review of the mineral service industry to stay afloat, grow and develop. The objectives of this study were to identify the internal performance and core competencies of Mineral Gas Station, to identify the external macro environment condition and external micro intensity of mineral service industry competition, to map the current position of the company, to recommend appropriate business strategy in facing competition pressure, and to develop the objectives and program of the company. This research used descriptive and quantitative analysis methods with a purposive sampling technique. The results show that the position of Mineral Gas Station on the intensity of mineral service competition is 'moderate' and is in quadrant of 'grow and build'. Therefore, the appropriate strategy is intensive strategy (market penetration, market development and product development. Mineral Gas Station require to conduct customer satisfaction surveys related to customer perspectives which becomes the most important strategic factor with a focus on customer complaint factor. Further research is needed by involving all external parties so that the results will be more independent.Keywords: mineral services, strategic planning, competition, mineral gas station, SucofindoABSTRAKPerencanaan strategik dibutuhkan organisasi dalam menghadapi persaingan bisnis saat ini dan masa depan yang semakin komplek. Demikian juga yang dibutuhkan SBU Mineral sebagai unit bisnis yang baru terbentuk 2015, dengan menganalisis faktor internal dan ekternal perusahaan serta tinjauan masa depan industri jasa mineral untuk tetap bertahan, tumbuh dan berkembang. Tujuan penelitian ini adalah

  12. Very heavy iron-punching concretes

    International Nuclear Information System (INIS)

    Dubois, F.

    1966-01-01

    The present report deals with all the heavy iron-punching concretes, metallic wastes produced by the transformation industry. After a detailed description of the physical properties of metallic aggregates, a classification of heavy mortars is given, into three main categories: steel-shot grouts d = 5,3 - 6; steel-shot grouts mixed with a mineral d = 3,7 - 4,2; injection heavy grouts d = 3,5 - 4. The following chapter describes iron-punching concretes the most used in the atomic industry: iron-punching concretes mixed with cast-iron - iron-punching concretes mixed with magnetite; iron-punching concretes mixed with barite; iron-punching concretes mixed with limonite; iron-punching concretes mixed with boron. The compositions of these concretes are given together with their physical and mechanical characteristics. Numerous diagrams make it possible to find rapidly the proportions of the constituents of these concretes as a function of the required density. Technical advice and specifications are given in an appendix together with a bibliography of these heavy concretes. (author) [fr

  13. Stellar core collapse and supernova

    International Nuclear Information System (INIS)

    Wilson, J.R.; Mayle, R.; Woosley, S.E.; Weaver, T.

    1985-04-01

    Massive stars that end their stable evolution as their iron cores collapse to a neutron star or black hole long been considered good candidates for producing Type II supernovae. For many years the outward propagation of the shock wave produced by the bounce of these iron cores has been studied as a possible mechanism for the explosion. For the most part, the results of these studies have not been particularly encouraging, except, perhaps, in the case of very low mass iron cores or very soft nuclear equations of state. The shock stalls, overwhelmed by photodisintegration and neutrino losses, and the star does not explode. More recently, slow late time heating of the envelope of the incipient neutron star has been found to be capable of rejuvenating the stalled shock and producing an explosion after all. The present paper discusses this late time heating and presents results from numerical calculations of the evolution, core collapse, and subsequent explosion of a number of recent stellar models. For the first time they all, except perhaps the most massive, explode with reasonable choices of input physics. 39 refs., 17 figs., 1 tab

  14. Quantification of mineral matter in commercial cokes and their parent coals

    Energy Technology Data Exchange (ETDEWEB)

    Sakurovs, Richard; French, David; Grigore, Mihaela [CRC for Coal in Sustainable Development, CSIRO Energy Technology, PO Box 330 Newcastle 2300 (Australia)

    2007-10-01

    The nature of mineral matter in coke is an important factor in determining the behaviour of coke in the blast furnace. However, there have been few quantitative determinations of the types of mineral matter in coke and the feed coal. Here we use a technique of quantitative X-ray diffraction - SIROQUANT trademark - to determine the nature and quantity of mineral matter in eleven cokes and their parent materials, using samples of coals and their cokes utilised commercially in blast furnaces around the world. In some of these coals a considerable proportion of the phosphorus was present as goyazite, an aluminium phosphate. In the cokes, most of the iron was incorporated into amorphous aluminosilicate material; metallic iron accounted for about 15% of the iron present, and a similar amount was present as sulfides. Potassium and sodium were largely present as amorphous aluminosilicate material. Most of the quartz in the coal was unaffected by the coking, but a small fraction was transformed into other minerals. Quartz is not completely inert during coking. The amount of the catalytic forms of iron in the coke - iron, iron oxides and iron sulfides - was not related to the amount of pyrite and siderite in the starting coal, indicating that estimation of catalytic iron requires investigation of the mineral matter in coke directly and cannot be estimated from the minerals in the coal. (author)

  15. Carbon mineralization and carbonate preservation in modern cold-water coral reef sediments on the Norwegian shelf

    Directory of Open Access Journals (Sweden)

    L. M. Wehrmann

    2009-04-01

    Full Text Available Cold-water coral ecosystems are considered hot-spots of biodiversity and biomass production and may be a regionally important contributor to carbonate production. The impact of these ecosystems on biogeochemical processes and carbonate preservation in associated sediments were studied at Røst Reef and Traenadjupet Reef, two modern (post-glacial cold-water coral reefs on the Mid-Norwegian shelf. Sulfate and iron reduction as well as carbonate dissolution and precipitation were investigated by combining pore-water geochemical profiles, steady state modeling, as well as solid phase analyses and sulfate reduction rate measurements on gravity cores of up to 3.25 m length. Low extents of sulfate depletion and dissolved inorganic carbon (DIC production, combined with sulfate reduction rates not exceeding 3 nmol S cm−3 d−1, suggested that overall anaerobic carbon mineralization in the sediments was low. These data showed that the coral fragment-bearing siliciclastic sediments were effectively decoupled from the productive pelagic ecosystem by the complex reef surface framework. Organic matter being mineralized by sulfate reduction was calculated to consist of 57% carbon bound in CH2O groups and 43% carbon in -CH2- groups. Methane concentrations were below 1 μM, and failed to support the hypothesis of a linkage between the distribution of cold-water coral reefs and the presence of hydrocarbon seepage. Reductive iron oxide dissolution linked to microbial sulfate reduction buffered the pore-water carbonate system and inhibited acid-driven coral skeleton dissolution. A large pool of reactive iron was available leading to the formation of iron sulfide minerals. Constant pore-water Ca2+, Mg2+ and Sr2+ concentrations in most cores and decreasing Ca2+ and Sr2+ concentrations with depth in core 23–18 GC indicated diagenetic carbonate precipitation. This was

  16. Electron Transfer Strategies Regulate Carbonate Mineral and Micropore Formation.

    Science.gov (United States)

    Zeng, Zhirui; Tice, Michael M

    2018-01-01

    Some microbial carbonates are robust biosignatures due to their distinct morphologies and compositions. However, whether carbonates induced by microbial iron reduction have such features is unknown. Iron-reducing bacteria use various strategies to transfer electrons to iron oxide minerals (e.g., membrane-bound enzymes, soluble electron shuttles, nanowires, as well as different mechanisms for moving over or attaching to mineral surfaces). This diversity has the potential to create mineral biosignatures through manipulating the microenvironments in which carbonate precipitation occurs. We used Shewanella oneidensis MR-1, Geothrix fermentans, and Geobacter metallireducens GS-15, representing three different strategies, to reduce solid ferric hydroxide in order to evaluate their influence on carbonate and micropore formation (micro-size porosity in mineral rocks). Our results indicate that electron transfer strategies determined the morphology (rhombohedral, spherical, or long-chained) of precipitated calcium-rich siderite by controlling the level of carbonate saturation and the location of carbonate formation. Remarkably, electron transfer strategies also produced distinctive cell-shaped micropores in both carbonate and hydroxide minerals, thus producing suites of features that could potentially serve as biosignatures recording information about the sizes, shapes, and physiologies of iron-reducing organisms. Key Words: Microbial iron reduction-Micropore-Electron transfer strategies-Microbial carbonate. Astrobiology 18, 28-36.

  17. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... Iron-Deficiency Anemia Iron-Deficiency Anemia Also known as Leer en español Iron-deficiency anemia is a ... address the cause of your iron deficiency, such as any underlying bleeding. If undiagnosed or untreated, iron- ...

  18. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... To Health Topics / Iron-Deficiency Anemia Iron-Deficiency Anemia Also known as Leer en español Iron-deficiency ... anemia. Blood tests to screen for iron-deficiency anemia To screen for iron-deficiency anemia, your doctor ...

  19. Iron-Deficiency Anemia

    Science.gov (United States)

    ... To Health Topics / Iron-Deficiency Anemia Iron-Deficiency Anemia Also known as Leer en español Iron-deficiency ... anemia. Blood tests to screen for iron-deficiency anemia To screen for iron-deficiency anemia, your doctor ...

  20. Reactor core structure

    International Nuclear Information System (INIS)

    Higashinakagawa, Emiko; Sato, Kanemitsu.

    1992-01-01

    Taking notice on the fact that Fe based alloys and Ni based alloys are corrosion resistant in a special atmosphere of a nuclear reactor, Fe or Ni based alloys are applied to reactor core structural components such as fuel cladding tubes, fuel channels, spacers, etc. On the other hand, the neutron absorption cross section of zirconium is 0.18 barn while that of iron is 2.52 barn and that of nickel is 4.6 barn, which amounts to 14 to 25 times compared with that of zirconium. Accordingly, if the reactor core structural components are constituted by the Fe or Ni based alloys, neutron economy is lowered. Since it is desirable that neutrons contribute to uranium fission with least absorption to the reactor core structural components, the reactor core structural components are constituted with the Fe or Ni based alloys of good corrosion resistance only at a portion in contact with reactor water, that is, at a surface portion, while the main body is constituted with zircalloy in the present invention. Accordingly, corrosion resistnace can be kept while keeping small neutron absorption cross section. (T.M.)

  1. Minerals Yearbook, volume I, Metals and Minerals

    Science.gov (United States)

    ,

    2018-01-01

    The U.S. Geological Survey (USGS) Minerals Yearbook discusses the performance of the worldwide minerals and materials industries and provides background information to assist in interpreting that performance. Content of the individual Minerals Yearbook volumes follows:Volume I, Metals and Minerals, contains chapters about virtually all metallic and industrial mineral commodities important to the U.S. economy. Chapters on survey methods, summary statistics for domestic nonfuel minerals, and trends in mining and quarrying in the metals and industrial mineral industries in the United States are also included.Volume II, Area Reports: Domestic, contains a chapter on the mineral industry of each of the 50 States and Puerto Rico and the Administered Islands. This volume also has chapters on survey methods and summary statistics of domestic nonfuel minerals.Volume III, Area Reports: International, is published as four separate reports. These regional reports contain the latest available minerals data on more than 180 foreign countries and discuss the importance of minerals to the economies of these nations and the United States. Each report begins with an overview of the region’s mineral industries during the year. It continues with individual country chapters that examine the mining, refining, processing, and use of minerals in each country of the region and how each country’s mineral industry relates to U.S. industry. Most chapters include production tables and industry structure tables, information about Government policies and programs that affect the country’s mineral industry, and an outlook section.The USGS continually strives to improve the value of its publications to users. Constructive comments and suggestions by readers of the Minerals Yearbook are welcomed.

  2. Laboratory of minerals purification

    International Nuclear Information System (INIS)

    2002-01-01

    The laboratory of minerals purification was organized in 1962 where with application of modern physical and chemical methods were investigated the mechanism of flotation reagents interaction with minerals' surface, was elaborated technologies on rising complexity of using of republic's minerals

  3. The role of mitochondria in cellular iron-sulfur protein biogenesis and iron metabolism.

    Science.gov (United States)

    Lill, Roland; Hoffmann, Bastian; Molik, Sabine; Pierik, Antonio J; Rietzschel, Nicole; Stehling, Oliver; Uzarska, Marta A; Webert, Holger; Wilbrecht, Claudia; Mühlenhoff, Ulrich

    2012-09-01

    Mitochondria play a key role in iron metabolism in that they synthesize heme, assemble iron-sulfur (Fe/S) proteins, and participate in cellular iron regulation. Here, we review the latter two topics and their intimate connection. The mitochondrial Fe/S cluster (ISC) assembly machinery consists of 17 proteins that operate in three major steps of the maturation process. First, the cysteine desulfurase complex Nfs1-Isd11 as the sulfur donor cooperates with ferredoxin-ferredoxin reductase acting as an electron transfer chain, and frataxin to synthesize an [2Fe-2S] cluster on the scaffold protein Isu1. Second, the cluster is released from Isu1 and transferred toward apoproteins with the help of a dedicated Hsp70 chaperone system and the glutaredoxin Grx5. Finally, various specialized ISC components assist in the generation of [4Fe-4S] clusters and cluster insertion into specific target apoproteins. Functional defects of the core ISC assembly machinery are signaled to cytosolic or nuclear iron regulatory systems resulting in increased cellular iron acquisition and mitochondrial iron accumulation. In fungi, regulation is achieved by iron-responsive transcription factors controlling the expression of genes involved in iron uptake and intracellular distribution. They are assisted by cytosolic multidomain glutaredoxins which use a bound Fe/S cluster as iron sensor and additionally perform an essential role in intracellular iron delivery to target metalloproteins. In mammalian cells, the iron regulatory proteins IRP1, an Fe/S protein, and IRP2 act in a post-transcriptional fashion to adjust the cellular needs for iron. Thus, Fe/S protein biogenesis and cellular iron metabolism are tightly linked to coordinate iron supply and utilization. This article is part of a Special Issue entitled: Cell Biology of Metals. Copyright © 2012 Elsevier B.V. All rights reserved.

  4. Formation of iron oxides from acid mine drainage and magnetic separation of the heavy metals adsorbed iron oxides

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Hee Won; Kim, Jeong Jin; Kim, Young Hun [Andong National University, Andong (Korea, Republic of); Ha, Dong Woo [Korea Electrotechnology Research Institute, Changwon (Korea, Republic of)

    2016-03-15

    There are a few thousand abandoned metal mines in South Korea. The abandoned mines cause several environmental problems including releasing acid mine drainage (AMD), which contain a very high acidity and heavy metal ions such as Fe, Cu, Cd, Pb, and As. Iron oxides can be formed from the AMD by increasing the solution pH and inducing precipitation. Current study focused on the formation of iron oxide in an AMD and used the oxide for adsorption of heavy metals. The heavy metal adsorbed iron oxide was separated with a superconducting magnet. The duration of iron oxide formation affected on the type of mineral and the degree of magnetization. The removal rate of heavy metal by the adsorption process with the formed iron oxide was highly dependent on the type of iron oxide and the solution pH. A high gradient magnetic separation (HGMS) system successfully separated the iron oxide and harmful heavy metals.

  5. South Africa's mineral industry

    International Nuclear Information System (INIS)

    1985-06-01

    The main aim of the Minerals Bureau in presenting this annual review is to provide an up-to-date reference document on the current state of the mineral industry in South Africa. This includes a brief look at the production, trade, economy, resources and deposits of precious metals and minerals, energy minerals, metallic minerals, and non-metallic minerals. One article discusses the production, trade, export, deposits and economy of uranium

  6. Transformer core

    NARCIS (Netherlands)

    Mehendale, A.; Hagedoorn, Wouter; Lötters, Joost Conrad

    2008-01-01

    A transformer core includes a stack of a plurality of planar core plates of a magnetically permeable material, which plates each consist of a first and a second sub-part that together enclose at least one opening. The sub-parts can be fitted together via contact faces that are located on either side

  7. Transformer core

    NARCIS (Netherlands)

    Mehendale, A.; Hagedoorn, Wouter; Lötters, Joost Conrad

    2010-01-01

    A transformer core includes a stack of a plurality of planar core plates of a magnetically permeable material, which plates each consist of a first and a second sub-part that together enclose at least one opening. The sub-parts can be fitted together via contact faces that are located on either side

  8. Miscellaneous Industrial Mineral Operations

    Data.gov (United States)

    Department of Homeland Security — This map layer includes miscellaneous industrial minerals operations in the United States. The data represent commodities covered by the Minerals Information Team...

  9. Interplay between black carbon and minerals contributes to long term carbon stabilization and mineral transformation

    Science.gov (United States)

    Liang, B.; Weng, Y. T.; Wang, C. C.; Chiang, C. C.; Liu, C. C.; Lehmann, J.

    2017-12-01

    Black carbon receives increasing global wide research attention due to its role in carbon sequestration, soil fertility enhancement and remediation application. Generally considered chemically stable in bulk, the reactive surface of BC can interplays with minerals and form strong chemical bondage, which renders physical protection of BC and contributes to its long term stabilization. Using historical BC-rich Amazonian Dark Earth (ADE), we probe the in-situ organo-mineral association and transformation of BC and minerals over a millennium scale using various synchrotron-based spectroscopic (XANES, FTIR) and microscopic (TXM) methods. Higher content of SRO minerals was found in BC-rich ADE compare to adjacent tropical soils. The iron signature found in BC-rich ADE was mainly ferrihydrite/lepidocrocite, a more reactive form of Fe compared to goethite, which was dominant in adjacent soil. Abundant nano minerals particles were observed in-situ associated with BC surface, in clusters and layers. The organo-mineral interaction lowers BC bioavailability and enhances its long-term stabilization in environment, while at the same time, transforms associated minerals into more reactive forms under rapid redox/weathering environment. The results suggest that mineral physical protection for BC sequestration may be more important than previous understanding. The scale up application of BC/biochar into agricultural systems and natural environments have long lasting impact on the in-situ transformation of associated minerals.

  10. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... making new blood cells. Visit our Aplastic Anemia Health Topic to learn more. ... recommend that you take iron supplements, also called iron pills or oral iron, by mouth once or several times a ...

  11. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... red meat, salmon, iron-fortified breads and cereals, peas, tofu, dried fruits, and dark green leafy vegetables. ... stored iron has been used. Ferritin is a protein that helps store iron in your body. Reticulocyte ...

  12. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... drinking black tea, which reduces iron absorption. Other treatments If you have chronic kidney disease and iron- ... and lifestyle changes to avoid complications. Follow your treatment plan Do not stop taking your prescribed iron ...

  13. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... diagnoses you with iron-deficiency anemia, your treatment will depend on the cause and severity of the ... of iron. The recommended daily amounts of iron will depend on your age, sex, and whether you ...

  14. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... heart failure . Increased risk of infections Motor or cognitive development delays in children Pregnancy complications, such as ... iron-deficiency anemia may require intravenous (IV) iron therapy or a blood transfusion . Iron supplements Your doctor ...

  15. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... for iron-deficiency anemia. Lifestyle habits Certain lifestyle habits may increase your risk for iron-deficiency anemia, including: Vegetarian or vegan eating patterns. Not eating enough iron-rich foods, such ...

  16. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... because your body’s intake of iron is too low. Low intake of iron can happen because of blood ... delivery or giving birth to a baby with low birth weight In people with chronic conditions, iron- ...

  17. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... breastfeeding. Recommended daily iron intake for children and adults. The table lists the recommended amounts of iron, ... increased need for iron during growth spurts. Older adults, especially those over age 65. Unhealthy environments Children ...

  18. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... girls. From birth to 6 months, babies need 0.27 mg of iron. This number goes up ... screen blood donors for low iron stores. Reliable point-of-care testing may help identify iron deficiency ...

  19. Iron metabolism and toxicity

    International Nuclear Information System (INIS)

    Papanikolaou, G.; Pantopoulos, K.

    2005-01-01

    Iron is an essential nutrient with limited bioavailability. When present in excess, iron poses a threat to cells and tissues, and therefore iron homeostasis has to be tightly controlled. Iron's toxicity is largely based on its ability to catalyze the generation of radicals, which attack and damage cellular macromolecules and promote cell death and tissue injury. This is lucidly illustrated in diseases of iron overload, such as hereditary hemochromatosis or transfusional siderosis, where excessive iron accumulation results in tissue damage and organ failure. Pathological iron accumulation in the liver has also been linked to the development of hepatocellular cancer. Here we provide a background on the biology and toxicity of iron and the basic concepts of iron homeostasis at the cellular and systemic level. In addition, we provide an overview of the various disorders of iron overload, which are directly linked to iron's toxicity. Finally, we discuss the potential role of iron in malignant transformation and cancer

  20. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... amount of iron, and medical conditions that make it hard for your body to absorb iron from ... hepcidin. Hepcidin prevents iron from leaving cells where it is stored or from being absorbed in the ...

  1. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... bleeding. If undiagnosed or untreated, iron-deficiency anemia can cause serious complications, including heart failure and development ...