This paper suggests that the substitution of C for O(!) (rather than C for Si!) in molten, amorphous, and crystalline silicate structures may provide a hitherto hidden reservoir of carbon in planetary interiors.
Impact glass linked to the 1.2-km-diameter Darwin crater in western Tasmaniais strewn over an area exceeding 400 km2 and is thought to have been ejected by a meteorite impact about 800 kyr ago into terrain consisting of rainforest and swamp. The authors have shown that biomarkers representative of plant species in the local ecosystem—including cellulose, lignin, aliphatic biopolymer and protein remnants—survived the Darwin impact. They found that inside the impact glass the organic components are trapped in porous carbon spheres. We propose that the organic material was captured within impact melt and preserved when the melt quenched to glass, preventing organic decomposition since the impact.
Életének 88. évében, 2013. április 15-én elhunyt Bárdossy György Széchenyi-díjas magyar geológus, geokémikus, a Magyar Tudományos Akadémia Földtudományok Osztályának Akadémiai Aranyérmes rendes tagja. A bauxitkutatás neves tudósa a karsztbauxit és a laterit előfordulásával és keletkezésével foglalkozott, emellett a radioaktív hulladékok elhelyezési lehetőségeit is vizsgálta, és úttörő szerepet töltött be a matematikai módszerek földtudományi területen történő bevezetésében, alkalmazásában.
Olivine is a major component of the mantle of differentiated bodies, including Earth.
Ath Godelitsas's insight:
Olivine was tentatively identified on Vesta asteroid, on the basis of spectral and colour data, but other observations did not confirm its presence. The authors here report that olivine is indeed present locally on Vesta’s surface but that, unexpectedly, it has not been found within the deep, south-pole basins, which are thought to be excavated mantle rocks. Instead, it occurs as near-surface materials in the northern hemisphere.
Researchers of the University of Göttingen substantially increase resolution at DESY´s light source PETRA III
Ath Godelitsas's insight:
The world’s sharpest X-ray beam shines at DESY. At the X-ray light source PETRA III, scientists from Göttingen generated a beam with a diameter of barely 5 nanometres – this is ten thousand times thinner than human hair. This fine beam of X-ray light allows focusing on smallest details. The research groups of Professor Tim Salditt from the Institute of X-ray Physics and of Professor Hans-Ulrich Krebs from the Institute of Materials Physics of the University of Göttingen published their work in the research journal Optics Express.
The authors developed a statistical risk model that classifies safe and unsafe areas with respect to geogenic arsenic contamination in China, using the threshold of 10 micrograms per liter, the World Health Organization guideline and current Chinese standard for drinking water. They estimate that 19.6 million people are at risk of being affected by the consumption of arsenic-contaminated groundwater.
Magnetotactic bacteria have the ability to synthesize nanocrystals of magnetite (Fe3O4) enabling them to align themselves with the terrestrial magnetic field in order to find the position in the water column that is most favorable to their survival.
The results show that the processes responsible for the unusual distribution of Fe at different stages of interaction with the asbestos fibres also involve Ca, P and Mg. It has been confirmed, by micro-XANES, that the dominant Fe form present in asbestos bodies is ferritin ((ferrihydrite containing protein), while the concurrent presence of haematite suggests alteration of iron chemistry during asbestos body permanence.
XAFS at Elettra is the Italian beamline dedicated to x-ray absorption spectroscopy. It is installed on a bending magnet source and it was designed to cover a wide energy range: from 2.4 to 27 keV meeting the needs of a large number of researchers in the area of conventional x-ray absorption spectroscopy.
The ocean's floors contain vast reserves of minerals, including manganese, iron, copper, nickel, gold and rare earth elements. The metals are stored in the sea floor, in nodules or around hydrothermal vents, some several thousand metres beneath the sea surface. Exploitation of these reserves is by no means a new idea, but it is only now becoming feasible, with higher metal prices and emerging technologies.
The authors used high-pressure and high-temperature experiments and in situ X-ray analysis to assess the properties of basaltic magmas under pressures of up to 5.5 GPa. They found that the magmas rapidly become denser with increasing pressure and show a viscosity minimum near 4 GPa. Magma mobility—the ratio of the melt–solid density contrast to the magma viscosity—exhibits a peak at pressures corresponding to depths of 120–150 km, within the asthenosphere, up to an order of magnitude greater than pressures corresponding to the deeper mantle and shallower lithosphere.
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.
The authors used Synchrotron X-ray tomography during battery operation to visualize and quantify the origins and evolution of electrochemical and mechanical degradation. Tomography provides the time-resolved, three-dimensional chemical composition and morphology within individual particles and throughout the electrode.
Bárdossy György (Szombathely, 1925. november 17. – Budapest, 2013. április 15.) Széchenyi-díjas magyar geológus, geokémikus, a Magyar Tudományos Akadémia rendes tagja. A bauxit kutatásának neves tudósa, a karsztbauxit és a laterit előfordulásával és keletkezésével foglalkozott. Emellett a radioaktív hulladékok elhelyezési lehetőségeit is vizsgálta.
Vor 100 Jahren, im Jahr 1912, hat Max von Laue die Beugung von Röntgenstrahlung an Kristallen entdeckt und damit das Tor zur Erforschung des Nanokosmos aufgestoßen. Die sogenannte Röntgenstrukturanalyse hat sich heute zu einem der wichtigsten Werkzeuge in der Nano- und Bioforschung entwickelt. Sie erlaubt, die molekulare und atomare Struktur der verschiedensten Materialien zu entschlüsseln. Etliche der heutigen Technologien und modernen Werkstoffe wären ohne dieses Wissen nicht denkbar. So liefert von Laues Methode unter anderem Informationen für die Entwicklung effizienterer Solarzellen, besserer Datenspeicher und neuer Arzneimittel. Der interdisziplinäre Nano-Bio-Forschungscampus, der rund um DESYs Röntgenlichtquelle PETRA III entsteht, führt von Laues Forschung ins 21. Jahrhundert. Daher hat die große PETRA III-Eperimentierhalle den Namen des Physikpioniers bekommen.
Ath Godelitsas's insight:
Deutsches Elektronen-Synchrotron (DESY), PETRA III
Silicate liquids play a key part at all stages of deep Earth evolution, ranging from core and crust formation billions of years ago to present-day volcanic activity.
Ath Godelitsas's insight:
Using the world's most brilliant X-ray source, scientists have for the first time peered into molten magma at conditions of the deep Earth mantle. The analysis at DESY's light source PETRA III revealed that molten basalt changes its structure when exposed to pressure of up to 60 gigapascals (GPa), corresponding to a depth of about 1400 kilometres below the surface. At such extreme conditions, the magma changes into a stiffer and denser form. The findings support the concept that the early Earth's mantle harboured two magma oceans, separated by a crystalline layer. Today, these presumed oceans have crystallised, but molten magma still exists in local patches and maybe thin layers in the mantle. See also: http://phys.org/news/2013-11-x-rays-reveal-earth-ancient-magma.html
The authors report a real-space visualization of the formation of hydrogen bonding in 8-hydroxyquinoline (8-hq) molecular assemblies on a Cu(111) substrate, using noncontact atomic force microscopy (NC-AFM).
According to Hochella at al. (GSA Meeting 2013), the adherence to the classic definition of a mineral has undoubtedly left large numbers of natural non-crystalline (amorphous) and poorly crystalline materials on the periphery, or worse, understudied and even unnoticed. Environmental mineralogy and nanomineralogy recognize that such materials are of exceptional importance in near-surface aqueous, soil, and atmospheric environments. These are some of the most important factors in environmental science as a whole. Indeed, relatively recently, there are environmentally important substances that have been formally recognized as minerals, such as ferrihydrite and schwertmannite, that are poorly ordered, to very poorly ordered using the traditional terminology. Perhaps they have been recognized as official minerals because of their abundance and/or geochemical importance. Certainly, our understanding of the structures of these materials, including the nature of structural order and disorder, has markedly improved due to the advancement and development of a suite of atomic structure analysis tools.
Magnetotactic bacteria align along the Earth’s magnetic field using an organelle called the magnetosome, a biomineralized magnetite (Fe(ii)Fe(iii)2O4) or greigite (Fe(ii)Fe(iii)2S4) crystal embedded in a lipid vesicle. Mutational analysis, enzyme kinetics, co-crystallization with iron(ii) and an in vitro MamP-assisted magnetite production assay establish MamP as an iron oxidase that contributes to the formation of iron(iii) ferrihydrite eventually required for magnetite crystal growth in vivo.
The iron concentration, distribution and speciation in diseased human lungs, monitored for the first time thanks to the high elemental and chemical sensitivity of synchrotron XRF spectro-imaging and micro-XANES, have shed light on the iron mobilization during asbestos permanence in lung tissue.
The study of nanostructured materials requires analytical methods that combine X-ray spectroscopy with electron microscopy. The Nanospectroscopy beamline at Elettra operates a state-of-the-art spectroscopic photoemission and photoemission electron microscope (SPELEEM). This powerful instrument offers a wide range of complementary methods including low energy electron microscopy (LEEM) providing structural, chemical and magnetic sensitivity. The lateral resolution of the microscope currently approaches few tens nm. The microscope is served by a high photon flux beamline, which can deliver elliptically polarised photons in the range 50 eV to 1000 eV.
The technique combines computed tomography (CT)—which makes "slices" of the 3-D structure (circles)—with x-ray particle distribution functions (PDFs, shown as graphs), to plot information about the internal nanostructure and chemistry (colors), pixel-by-pixel in three dimensions.