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Synchrotron study of ceria nanoparticles invokes the picture of an electron sponge

Synchrotron study of ceria nanoparticles invokes the picture of an electron sponge | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
Ath Godelitsas's insight:

The authors monitored the Ce electronic structure during the synthesis and catalase mimetic reaction of colloidal ceria nanoparticles under in situ conditions. By means of high-energy resolution hard X-ray spectroscopy, they directly probed the Ce 4f and 5d orbitals. The study invokes the picture of an electron sponge.

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Discovery of bridgmanite, the most abundant mineral in Earth, in a shocked meteorite

Discovery of bridgmanite, the most abundant mineral in Earth, in a shocked meteorite | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
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The authors report the discovery of this important phase as a mineral in the Tenham L6 chondrite and approved by the International Mineralogical Association (specimen IMA 2014-017). MgSiO3-perovskite is now called bridgmanite.

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Lonsdaleite is faulted and twinned cubic diamond and does not exist as a discrete material

Lonsdaleite is faulted and twinned cubic diamond and does not exist as a discrete material | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
Ath Godelitsas's insight:

The authors showed that defects in cubic diamond provide an explanation for the characteristic d-spacings and reflections reported for lonsdaleite. Ultrahigh-resolution electron microscope images demonstrate that samples displaying features attributed to lonsdaleite consist of cubic diamond dominated by extensive {113} twins and {111} stacking faults.

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Molten uranium dioxide structure and dynamics

Molten uranium dioxide structure and dynamics | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it

See also: http://www.mpi.stonybrook.edu/people/LawrieSkinner/index.html

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The authors have combined laser heating, sample levitation, and Synchrotron x-rays to obtain pair distribution function measurements of hot solid and molten UO2.

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Periodico di Mineralogia Vol. 83,2 september 2014 | Edizioni Nuova Cultura

Periodico di Mineralogia Vol. 83,2 september 2014 | Edizioni Nuova Cultura | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
CONTENTS Angelo De Min, Francesco Princivalle and Davide Lenaz Geochemistry of the Late Mesozoic - Early Cenozoic turbidites from the NE part of the Adria microplate Bogdan Constantinescu, Daniela Cristea-Stan, Imre Kovács and Zoltan...
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Nanoscale evidence for uranium mobility in zircon and the discordance of U–Pb chronometers

Nanoscale evidence for uranium mobility in zircon and the discordance of U–Pb chronometers | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it

Fractures and pores represent the vectors for fluid mediated open system behavior. STEM images demonstrate the presence of U-rich clusters (<70 nm) with uraninite structure within the porosity. At high magnification, pores are surrounded by a low density halo (<100 nm) and are coated by a high density wall (<50 nm) enriched in U or Ca or both.

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Predicting sediment and cesium-137 discharge from catchments in eastern Fukushima

Predicting sediment and cesium-137 discharge from catchments in eastern Fukushima | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
Ath Godelitsas's insight:

This paper reports simulations of soil erosion, sediment movement, and the resulting migration of cesium-137 (137Cs) in eastern Fukushima Prefecture after the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident in Japan.

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Arsenic-Rich Acid Mine Water with Extreme Arsenic Concentration

Arsenic-Rich Acid Mine Water with Extreme Arsenic Concentration | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
Ath Godelitsas's insight:

Extremely arsenic-rich acid mine waters have developed by weathering of native arsenic in a sulfide-poor environment on the 10th level of the Svornost mine in Jáchymov (Czech Republic). The EXAFS spectra on the As K edge can be interpreted in terms of arsenic polymerization in the aqueous solution. The secondary mineral that precipitates in the droplets is kaatialaite [Fe3+(H2AsO4)3·5H2O]. The extreme conditions make this environment unfavorable for intensive microbial colonization, but our first results show that certain microorganisms can adapt even to these harsh conditions.

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Potassium-Exchanged Natrolite Zeolite Under Pressure. Computational Study vs Experiment

Potassium-Exchanged Natrolite Zeolite Under Pressure. Computational Study vs Experiment | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
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Using density functional theory thw authors modeled the effects of pressure on K-exchanged natrolite zeolite.

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Incorporation of a Recombinant Biomineralization Fusion Protein into the Crystalline Lattice of Calcite

Incorporation of a Recombinant Biomineralization Fusion Protein into the Crystalline Lattice of Calcite | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
Ath Godelitsas's insight:

The authors demonstrate that GFP-perlucin derivatives become incorporated into the calcite structure and induce concentration-dependent anisotropic lattice distortions along the host’s c-axis. In contrast, GFP alone is hardly incorporated at all. The observed lattice distortions and peculiar microstructure of the crystals are comparable to those previously observed in biogenic calcite.

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Biomineralization: Long-Term Effectiveness of Polysaccharides on the Growth and Dissolution of Calcite

Biomineralization: Long-Term Effectiveness of Polysaccharides on the Growth and Dissolution of Calcite | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it

Ancient polysaccharide (PS) extracted from a ∼70 Ma biogenic calcite sediment (chalk) have a strong adsorption to inorganic calcite and causes a dramatic morphology change during growth and dissolution. Our results demonstrate that complex PS, besides being a clever gateway for shape-control during biomineralization, also can be extremely robust. This holds promise for smart material engineering and scale prevention.

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The effect of otoconial proteins Fetuin A, osteopontin and otoconin 90 on the nucleation and growth of calcite

The effect of otoconial proteins Fetuin A, osteopontin and otoconin 90 on the nucleation and growth of calcite | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
Ath Godelitsas's insight:

In situ atomic force microscopy (AFM) studies of the effects of these proteins on the growth of atomic steps on calcite surfaces were performed to obtain insight into their effects on the growth kinetics.

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Cambridge Journals Online - Microscopy and Microanalysis - Abstract - Application of Cathodoluminescence Microscopy and Spectroscopy in Geosciences

Cambridge Journals Online - Microscopy and Microanalysis - Abstract - Application of Cathodoluminescence Microscopy and Spectroscopy in Geosciences | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
Cathodoluminescence (CL) microscopy and spectroscopy are luminescence techniques with widespread applications in geosciences. Many rock-forming and accessory minerals show CL characteristics, which can be successfully used in geoscientific research.
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Sulfate was a trace constituent of Archean seawater

Sulfate was a trace constituent of Archean seawater | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
Ath Godelitsas's insight:

Using models informed by sulfur cycling in Lake Matano, the authors infer Archean seawater sulfate concentrations of less than 2.5 micromolar. At these low concentrations, marine sulfate residence times were likely 103 to 104 years, and sulfate scarcity would have shaped early global biogeochemical cycles, possibly restricting biological productivity in Archean oceans.

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Deep-Earth carbon offers clues on origin of life

Deep-Earth carbon offers clues on origin of life | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
New findings by a Johns Hopkins University-led team reveal long unknown details about carbon deep beneath Earth's surface and suggest ways this subterranean carbon might have influenced the history of life on the planet.
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Porosity and distribution of water in perlite from the island of Milos, Greece

Porosity and distribution of water in perlite from the island of Milos, Greece | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
Ath Godelitsas's insight:

The spatial distribution of water and/or pores was investigated using different methods (CT: computer tomography, FIB: scanning electron microscopy including focused ion beam technology, IRM: infrared microscopy). Computer tomography (CT) showed large macropores (20 – 100 μm) and additionally revealed a mottled microstructure of the silicate matrix with low density areas up to a few μm in diameter. Scanning electron microscopy (FIB) confirmed the presence of μm sized pores and IRM showed the filling of these pores with water. In summary, two types of pores were found.

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Organic carbon at depth

Organic carbon at depth | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
Earth/'s deep carbon cycle is poorly constrained. Theoretical calculations suggest that large amounts of carbon are returned to Earth/'s surface as organic and inorganic carbon ions dissolved in subduction-zone fluids.
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Photovoltage of Iron Pyrite Single Crystals

Photovoltage of Iron Pyrite Single Crystals | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
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The authors report a comprehensive investigation on {100}-faceted n-type iron pyrite single crystals to understand its puzzling low VOC. They utilized electrical transport, optical spectroscopy, surface photovoltage, photoelectrochemical measurements in aqueous and acetonitrile electrolytes, UV and X-ray photoelectron spectroscopy, and Kelvin force microscopy to characterize the bulk and surface defect states and their influence on the semiconducting properties and solar conversion efficiency of iron pyrite single crystals. These insights were used to develop a circuit model analysis for the electrochemical impedance spectroscopy that allowed a complete characterization of the bulk and surface defect states and the construction of a detailed band energy diagram for iron pyrite crystals.

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Silica hydrate preserved with δ18O-rich quartz in copper-gold deposit at El Indio, Chile

Silica hydrate preserved with δ18O-rich quartz in copper-gold deposit at El Indio, Chile | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
Ath Godelitsas's insight:

Here, the auuthors show for the first time that aggregates of euhedral quartz microcrystals preserve cryptocrystalline cores that contain silica hydrates ‘opal’ and moganite. We propose that these phases are metastable remnants of progressive dehydration from a precursor silica hydrate phase.

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New material steals oxygen from air

New material steals oxygen from air | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
Researchers in Denmark have synthesized crystalline materials that can bind and store oxygen in high concentrations. The stored oxygen can be released again when and where it is needed.
Ath Godelitsas's insight:

See the paper: http://pubs.rsc.org/en/Content/ArticleLanding/2014/SC/C4SC01636J#!divAbstract

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Studying X-ray Absorption Spectroscopy With Q-Chem

The spectroscopy of core electrons has a long history and is used in many areas of research. The spectroscopy of core electrons offers a number of advantages...
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Difference in the Conformation and Dynamics of Aspartic Acid on Calcite Surface

Difference in the Conformation and Dynamics of Aspartic Acid on Calcite Surface | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
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The simulations indicate that the amino acid binds indirectly to the {104} plane, whereas it binds directly to the {110} plane. The simulations also indicate that the acid binds directly to the acute step edge but does not bind to the obtuse step edge.

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Interactions of Scalenohedral Calcite Crystals with Acidic Amino Acid Derivatives of Salicylic Acid

Interactions of Scalenohedral Calcite Crystals with Acidic Amino Acid Derivatives of Salicylic Acid | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it

The kinetics of scalenohedral calcite crystal growth in the presence of N-salicyloil-l-aspartic (N-Sal-Asp) and N-salicyloil-l-glutamic acid (N-Sal-Glu), as selected models of anti-inflammatory drug-like substances, were analyzed in order to study the molecular interactions of the selected salicylates with scalenohedral {2 1 4} surfaces.

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Doping Incompatible Elements into Calcite through Amorphous Calcium Carbonate

Doping Incompatible Elements into Calcite through Amorphous Calcium Carbonate | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
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Doping large amounts of Sr2+ into calcite was achieved by pressurizing amorphous calcium carbonate (ACC).

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The Multiple Structures of Vaterite

The Multiple Structures of Vaterite | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it

The disordered structure of vaterite, a CaCO3 polymorph that plays a crucial role in biomineralization, has remained an enigma for over 50 years. Here, the structural complexity is explained in terms of different possible layer stacking, rotational freedom of carbonate units, and chirality. A relationship has then been established among the three most recently proposed models.

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Hidden values in bauxite residue (red mud): Recovery of metals

Hidden values in bauxite residue (red mud): Recovery of metals | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
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Red mud, in most cases, contains elevated concentrations of iron in addition to aluminium, titanium, sodium and valuable rare earth elements. Given the scarcity of iron supply globally, the iron content of red mud has attracted increasing research interest. This paper presents a critical overview of the current techniques employed for iron recovery from red mud. Information on the recovery of other valuable metals is also reviewed to provide an insight into the full potential usage of red mud as an economic resource rather than a waste.

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