Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience
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X-ray Laser Brings Gold Exploration to the Nanoscale

A movie showing a three-dimensional image of a gold nanocrystal 110 picoseconds after excitation with a laser

 

 

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Scientists can now routinely detect and study single molecules and nanoparticles. However, direct observation of chemical processes and/or atomic motions in real time remains a challenge, primarily because ultrafast (subpicosecond) time resolution is needed. Optical techniques have recently been developed to study the dynamics of individual molecules or nanoparticles where two laser beams (a pump and a probe) are focused onto a single nano-object under a microscope. The spatial resolution of these measurements is limited by the diffraction of light, so that the movements of the individual atoms can only be inferred. Clark et al. (http://www.sciencemag.org/content/341/6141/56.abstract) present a study of the lattice motions of individual gold nanoparticles recorded using ultrafast coherent x-ray pulses as a probe. These measurements yield three-dimensional images of the atomic displacements in the particles as a function of time, with a spatial resolution that is orders of magnitude better than what can be achieved with optical microscopes.

 

 

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Restraining Na-Montmorillonite Delamination in Water by Adsorption of Sodium Dodecyl Sulfate or Octadecyl Trimethyl Ammonium Chloride on the Edges

Restraining Na-Montmorillonite Delamination in Water by Adsorption of Sodium Dodecyl Sulfate or Octadecyl Trimethyl Ammonium Chloride on the Edges | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
The delamination of montmorillonite in water leads to sliming in ore slurry, which is detrimental to mineral flotation and solid/water separation. In this work, the delamination of Na-montmorillonite (Na-MMT) has been restrained by sodium dodecyl sulfate (SDS) or octadecyl trimethyl ammonium chloride (1831) through the adsorption on the edge of the mineral. The experimental results have shown that the pretreatment by adding SDS and 1831 could greatly reduce the Stokes size percentage of −1.1 µm particles in the aqueous Na-MMT suspension. From the X-ray diffractometer (XRD) results, the interlayer spacing of the MMT pre-treated by SDS and 1831 is smaller than that of original MMT particles. Adsorption position of SDS and 1831 on MMT surfaces was analyzed by the measurements of adsorption capacity of SDS and 1831, inductively-coupled plasma spectra, and zeta potential before and after the plane surface of MMT was covered with tetraethylenepentaminecopper ([Cu(tetren)]2+). The results indicated that SDS and 1831 are adsorbed on the edge and the whole surface of Na-MMT, respectively. Delamination of MMT could be well restrained by the adsorption of SDS and 1831 on the edges of MMT.
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Minerals with metal-organic framework structures

Minerals with metal-organic framework structures | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
Metal-organic frameworks (MOFs) are an increasingly important family of advanced materials based on open, nanometer-scale metal-organic architectures, whose design and synthesis are based on the directed assembly of carefully designed subunits. We now demonstrate an unexpected link between mineralogy and MOF chemistry by discovering that the rare organic minerals stepanovite and zhemchuzhnikovite exhibit structures found in well-established magnetic and proton-conducting metal oxalate MOFs. Structures of stepanovite and zhemchuzhnikovite, exhibiting almost nanometer-wide and guest-filled apertures and channels, respectively, change the perspective of MOFs as exclusively artificial materials and represent, so far, unique examples of open framework architectures in organic minerals.
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These 25 pictures will make you completely re-evaluate your existence. Just WHOA. | Interesting-Stuff

These 25 pictures will make you completely re-evaluate your existence. Just WHOA.    | Interesting-Stuff | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
The universe is huge and we are tiny. But just how tiny are From Interesting-Stuff
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A lead isotope perspective on urban development in ancient Naples

A lead isotope perspective on urban development in ancient Naples | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
A well-dated sedimentary sequence from the ancient harbor of Naples sheds new light on an old problem: could the great AD 79 Vesuvius eruption have affected the water supply of the cities around the Bay of Naples? The authors here show, using Pb isotopes, that this volcanic catastrophe not only destroyed the urban lead pipe water supply network, but that it took the Roman administration several decades to replace it, and that the commissioning of the new system, once built, occurred nearly instantaneously. Moreover, discontinuities in the Pb isotopic record of the harbor deposits prove a powerful tool for tracking both Naples’ urbanization and later major conflicts at the end of the Roman period and in early Byzantine times.
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Control of Earth-like magnetic fields on the transformation of ferrihydrite to hematite and goethite

Control of Earth-like magnetic fields on the transformation of ferrihydrite to hematite and goethite | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
Hematite and goethite are the two most abundant iron oxides in natural environments.
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Ferrihydrite was aged at 95 °C in magnetic fields ranging from ~0 to ~100 μT. The results indicate a large influence of the applied magnetic field on hematite and goethite growth from ferrihydrite.
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Nanoanalytical Electron Microscopy Reveals a Sequential Mineralization Process

Nanoanalytical Electron Microscopy Reveals a Sequential Mineralization Process | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
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To better understand the process of bone mineralization in the extracellular matrix, the authors used nanoanalytical electron microscopy techniques to examine an in vitro model of bone formation.
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Effect of pH on Amorphous Calcium Carbonate Structure and Transformation

Effect of pH on Amorphous Calcium Carbonate Structure and Transformation | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
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The authors used pair distribution function (PDF) analysis to provide evidence that the local structure of ACC gradually changes as the pH of the synthesis solutions is increased from 10.6 to 12.7, at ambient conditions.
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Cook Island artifact geochemistry demonstrates spatial and temporal extent of pre-European interarchipelago voyaging in East Polynesia

Cook Island artifact geochemistry demonstrates spatial and temporal extent of pre-European interarchipelago voyaging in East Polynesia | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
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An X-ray spectroscopic perspective on Messinian evaporite from Sicily

An X-ray spectroscopic perspective on Messinian evaporite from Sicily | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
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The dominant molecular host site of Mg and S obtained by X-ray absorption near edge structure (XANES) is applied to specify the hydrochemistry of hypersaline brines and the presence of diagenetic minerals, thus shedding light on evaporative concentration processes in the Caltanissetta Basin of Sicily.
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Direct and Facile Room-Temperature Synthesis of Nanocrystalline Gypsum

Direct and Facile Room-Temperature Synthesis of Nanocrystalline Gypsum | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
Scanning electron micrographs present an interesting phenomenon of formation of microcracks in the nano-CaFeO2.5 pellet during oxidation, leading to nucleation of gypsum within the cracks. The hardness and compressive strength improved by a factor of 1.5 (63% higher) and 1.7, respectively.
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Thin Ice Films at Mineral Surfaces

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Thin ice films at the surfaces of the majority of minerals considered in this work (i.e. metal (oxy)(hydr)oxides, phyllosilicates, silicates, volcanic ash, Arizona Test Dust) produced intense O-H stretching bands at ~3400 cm-1, attenuated bands at ~3200 cm-1 and liquid-water-like bending band at ~1640 cm-1, irrespective of structure and composition. Illite, a non-expandable phyllosilicate, is the only mineral that stabilized a form of ice that was strongly resilient to sublimation in temperatures as low as -50 °C.
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Deep-Mined Geological Disposal of Radioactive Waste

Deep-Mined Geological Disposal of Radioactive Waste | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
Elements, An International Magazine of Mineralogy, Geochemistry, and Petrology.
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A distinct source and differentiation history for Kolumbo submarine volcano #Santorini #Greece

A distinct source and differentiation history for Kolumbo submarine volcano #Santorini #Greece | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
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This study reports the first detailed geochemical characterization of Kolumbo submarine volcano in order to investigate the role of source heterogeneity in controlling geochemical variability within the Santorini volcanic field in the central Aegean arc. Kolumbo, situated 15 km to the northeast of Santorini, last erupted in 1650 AD and is thus closely associated with the Santorini volcanic system in space and time. Samples taken by remotely-operated vehicle that were analyzed for major element, trace element and Sr-Nd-Hf-Pb isotope composition include the 1650 AD and underlying K2 rhyolitic, enclave-bearing pumices that are nearly identical in composition (73 wt.% SiO2, 4.2 wt.% K2O). Lava bodies exposed in the crater and enclaves are basalts to andesites (52–60 wt.% SiO2). Biotite and amphibole are common phenocryst phases, in contrast with the typically anhydrous mineral assemblages of Santorini. The strong geochemical signature of amphibole fractionation and the assimilation of lower crustal basement in the petrogenesis of the Kolumbo magmas indicates that Kolumbo and Santorini underwent different crustal differentiation histories and that their crustal magmatic systems are unrelated. Moreover, the Kolumbo samples are derived from a distinct, more enriched mantle source that is characterized by high Nb/Yb (>3) and low 206Pb/204Pb (<18.82) that has not been recognized in the Santorini volcanic products. The strong dissimilarity in both petrogenesis and inferred mantle sources between Kolumbo and Santorini suggests that pronounced source variations can be manifested in arc magmas that are closely associated in space and time within a single volcanic field.
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#Uranium - bearing francolites present in organic-rich limestones of NW #Greece

#Uranium - bearing francolites present in organic-rich limestones of NW #Greece | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
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Synchrotron radiation techniques (μ-XRF and μ-XANES) were applied to the study of organic-rich phosphatized limestones of NW Greece (Epirus). The results revealed uranium accumulation in areas of the material containing, among others, carbonate apatite (francolite) and organic matter. The UL3-edge of μ-XANES spectra showed that uranium was present in tetravalent form. U-bearing francolite crystals were separated from the rock and characterized by Raman spectroscopy and microprobe. The analysis of the crystals also indicated the presence of sodium and sulfur. The uranium presence in the crystals was also visualized, after neutron irradiation and etching, by the observation of the fission tracks.
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The Role of Iron-Bearing Minerals in NO2 to HONO Conversion on Soil Surfaces

The Role of Iron-Bearing Minerals in NO2 to HONO Conversion on Soil Surfaces | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
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The authors used coated-wall flow tube measurements of NO2 reactivity on environmentally relevant surfaces (Fe (hydr)oxides, clay minerals, and soil from Arizona and the Saharan Desert) and detailed mineralogical characterization of substrates to show that reduction of NO2 by Fe-bearing minerals in soil can be a more important source of HONO than the putative NO2 hydrolysis mechanism.
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Three-dimensional textural and quantitative analyses of orogenic gold at the nanoscale

Three-dimensional textural and quantitative analyses of orogenic gold at the nanoscale | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
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Recent advances in lab-based and synchrotron radiation–based X-ray computed microtomography and nanotomography have made it possible to visualize and quantify rock volumes in a 3-D space. In this study, the authors analyzed microscale textures in oriented drill cores from the world-class Suurikuusikko orogenic gold deposit of northern Finland using lab-based X-ray computed microtomography.
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Discovery of alunite in Cross crater, Terra Sirenum, Mars: Evidence for acidic, sulfurous waters

Discovery of alunite in Cross crater, Terra Sirenum, Mars: Evidence for acidic, sulfurous waters | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
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Combining spectral data with high-resolution images, the authors map a large (10 km × 5 km) alunite-bearing deposit in southwest Cross crater, widespread kaolin-bearing sediments with variable amounts of alunite that are layered in <10 m scale beds, and silica- and/or montmorillonite-bearing deposits that occupy topographically lower, heavily fractured units.
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Water of Hydration Dynamics in Minerals Gypsum and Bassanite: Ultrafast 2D IR Spectroscopy of Rocks

Water of Hydration Dynamics in Minerals Gypsum and Bassanite: Ultrafast 2D IR Spectroscopy of Rocks | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
Here ultrafast nonlinear infrared (IR) techniques, two-dimensional infrared (2D IR) and polarization selective pump–probe (PSPP) spectroscopies, were used to measure the dynamics and disorder of water of hydration in two minerals, gypsum (CaSO4·2H2O) and bassanite (CaSO4·0.5H2O).
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NASA scientists discover unexpected mineral on Mars

NASA scientists discover unexpected mineral on Mars | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
National Academy of Sciences
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Which Inorganic Structures are the Most Complex?

Which Inorganic Structures are the Most Complex? | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
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Over the last hundred years, about 150 000 of inorganic crystal structures have been elucidated and visualized.  In this review the author uses information theory to characterize complexity of inorganic structures in terms of their information content.
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Measurement of Uranium Isotopes in Particles of U3O8 by Secondary Ion Mass Spectrometry–Single-Stage Accelerator Mass Spectrometry (SIMS–SSAMS)

Measurement of Uranium Isotopes in Particles of U3O8 by Secondary Ion Mass Spectrometry–Single-Stage Accelerator Mass Spectrometry (SIMS–SSAMS) | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
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A commercial secondary ion mass spectrometer (SIMS) was coupled to a ± 300 kV single-stage accelerator mass spectrometer (SSAMS).
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