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This contribution tries to indicate to the clinician what kind of information can be investigated through X-ray fluorescence, what kind of information can be extracted from this spectroscopy and finally how it competes with other tools described in previous publications such as Fourier Transform Infrared or Raman spectroscopy, X-ray Absorption Near Edge Structure spectroscopy and X-ray diffraction. To attain this goal, several examples based on X-ray fluorescence experiments performed on biological samples namely concretions, medical devices, biological fluids as well as tissues are presented. [ABSTRACT FROM AUTHOR]

Abstract: The geochemical partitioning of bromine between hydrous haplogranitic melts, initially enriched with respect to Br and aqueous fluids, has been continuously monitored in situ during decompression. Experiments were carried out in diamond anvil cells from 890°C to room temperature and from 1.7GPa to room pressure, typically from high P, T conditions corresponding to total miscibility (presence of a supercritical fluid). Br contents were measured in aqueous fluids, hydrous melts and supercritical fluids. Partition coefficients of bromine were characterized at pressure and temperature between fluids, hydrous melts and/or glasses, as appropriate: D Br fluid/melt =(Br)fluid/(Br)melt, ranges from 2.18 to 9.2±0.5 for conditions within the ranges 0.66–1.7GPa, 590–890°C; and D Br fluid/glass =(Br)fluid/(Br)glass ranges from 60 to 375 at room conditions. The results suggest that because high pressure melts and fluids are capable of accepting high concentrations of bromine, this element may be efficiently removed from the slab to the mantle source of arc magmas. We show that Br may be highly concentrated in subduction zone magmas and strongly enriched in subduction-related volcanic gases, because its mobility is strongly correlated with that of water during magma degassing. Furthermore, our experimental results suggest that a non negligible part of Br present in the subducted slab may remain in the down-going slab, being transported toward the transition zone. This indicates that the Br cycle in subduction zones is in fact divided in two related but independent parts: (1) a shallower one where recycled Br may leave the slab with a water and silica-bearing “fluid” leading to enriched arc magmas that return Br to the atmosphere. (2) A deeper cycle where Br may be recycled back to the mantle maybe to the transition zone, where it may be present in high pressure water-rich metasomatic fluids. [Copyright &y& Elsevier]

The corrosion of C-steel in contact with the Cox claystone was studied under aerated conditions at 50°C, for 7 years, in a simplified laboratory experiment. A multi-scale and multi-technique approach, including SEM-EDX, Raman spectroscopy and STXM, was used to determine the nature and structure of the corrosion products and to better understand the mechanisms involved in the observed degradation. The effects of temperature, oxygen supply and the local influence of the composition and density of the claystone were examined here. • Corrosion products were mainly composed of goethite. • Sulphides formed on the bare metal surface even in aerated conditions. • Samples closer to the oxygen source were heavily corroded. • Dense claystone favoured the formation of phyllosilicates in the goethite matrix. [ABSTRACT FROM AUTHOR]

The exploration of archaeological heritage aims at understanding past societies through the study of ancient materials. While archaeometric analysis provides valuable insights, invasive sampling raises ethical concerns and is often restricted, necessitating the development of non-invasive techniques. This study presents a methodology based on X-Ray Diffraction using synchrotron radiation. The approach involves the elaboration and characterization of model alloys, with X-ray data analysis using Rietveld refinement and Williamson-Hall plot method. Phase identification along with crystallographical investigations conducted on three medieval armours provides insights into manufacturing techniques and highlights the method's limitation. [ABSTRACT FROM AUTHOR]

Lapidary craftsmanship was an important part of the material culture of Amerindians in the Antilles during the Early Ceramic period (400 BCE to 400 CE). Exhaustive analysis of archaeological beads and pendants from the French islands of the Lesser Antilles has revealed a green lapidary material used for the production of nine artifacts from five archaeological sites: sudoite. This di-trioctahedral member of the chlorite group has the relatively simple chemical formula of Mg2Al3Si3AlO10(OH)8. Previously unknown in sizes suitable for carving, it has never before been identified in any lapidary production and therefore warranted a multi-analytical nondestructive approach to confirm this identification. The analysis was conducted through Raman spectroscopy, FTIR spectroscopy, and X-ray diffraction. The texture and the chemical composition were assessed through SEM-EDS. Color, UV luminescence, and other gemological parameters were studied through standard gemological methods, UV-Vis-NIR spectroscopy, and fluorimetry. Finally, the provenance of the material is considered following a geological approach. The recovery of sudoite artifacts in several archaeological Amerindian sites of the Lesser Antilles supports the already established theory of a pan-Caribbean trade network as old as the first several centuries Before the Common Era. [ABSTRACT FROM AUTHOR]

Degradation state evaluation, corrosion diagnosis methods' reliability, and also the development and improvement of conservation strategies are dramatically important to preserve iron archaeological objects. In this way, dechlorination processes for iron artefacts are traditionally used in conservation workshops to stabilize objects retrieved from archaeological excavations. This paper aims at presenting unpublished results but also to give an overview of the last 10 years study of stabilization processes using synchrotron X-ray absorption spectroscopy at the Cl K-edge as a key approach: first to decipher the corrosion patterns involving Cl ions on iron artefacts, and second to understand, mostly by in situ observation, the dechlorination processes. Wrought iron bars found on Gallo-Roman shipwrecks were studied. The difference in reactivity involved in the corrosion processes make it essential to distinguish and locate the phases in the heterogeneous corrosion layers. XANES at the Cl K-edge is a relevant technique to determine the Cl chemical form, distribution and its role in each phase's stability. Chloride ions may be trapped inside the structure of iron oxyhydroxide as akaganeite β-FeO1−x(OH)1+xClx and β- or γ-ferrous hydroxychlorides β-Fe2(OH)3Cl. Some Cl may also be adsorbed at the surface of the grains of the various phases present, i.e. not only the previsouly cited Cl-containing phases but also other oxyhydroxydes as lepidocrocite and goethite as shown by the XANES spectra. [ABSTRACT FROM AUTHOR]

A side effect of magnetron sputtering is the production of neutral working gas atoms backscattered from the cathode. Their influence on the morphology of sputter-deposited thin films, though, is usually neglected, which may not always be justified. In particular, for high-power impulse magnetron sputtering with its high negative cathode potential during the discharge pulse in combination with heavy metal targets, this effect can be important. In this work, we find experimentally that the grain size of magnetron-sputtered δ-TaN films is considerably reduced at high negative cathode potential and without the use of a substrate bias. For these deposition conditions, computer calculations show a high rate of backscattered neutrals with energies >100 eV, which is only a factor of 10 to 20 lower than the total deposition rate of sputtered species. Such a significant fraction of energetic backscattered neutrals can readily impede grain growth by the incorporation of defects followed by renucleation. Thermalization of the energetic neutrals by the process gas is shown to be insufficient for typical magnetron operating pressures and cathode-substrate distances. The methodology presented here can be used to explain similar results of shrinking grains with increased negative cathode potential for other material systems. [ABSTRACT FROM AUTHOR]

A carbon steel container including nuclear glass has been altered for 2 years in Andra's Underground Research Laboratory to simulate the behaviour of waste package. Post-mortem analyses at different scales (macro-micro-nano) have been performed to identify neoformed phases on iron corrosion products (ICP) and in the glass alteration layer (GAL). It has been shown at nanometric scale that important quantities of iron and silicon were found in the GAL and in the ICP respectively. Using a comparative approach with phyllosilicate references, STXM, at Si-K edge, suggests presence of trioctahedral species in the GAL and in ICP. Relevant fits of the STXM spectra are obtained with a Fe-rich chlorite for the nanostructured GAL, which could be formed according to chloritisation mechanism. This paper is part of a supplement on the 6th International Workshop on Long-Term Prediction of Corrosion Damage in Nuclear Waste Systems. [ABSTRACT FROM AUTHOR]

Discharge of wastewater leading to notable soil surface contamination is widely reported. But few works highlight the fast dynamics of soils and their morphological transformations that may result from such anthropogenic activities. Near Paris (France), sandy Luvisols were irrigated with urban wastewater since the 1890s. Within and outside the discharge area, the soil cover presents decameter-sized cryogenic structures. We studied macro morphological soil characteristics, soil chemistry and clay mineralogy on selected bulk samples, as well as contemporary pedofeatures and related metal pollutant distribution patterns in soil thin sections from subsurface horizons. Annual repetitive waterlogging and drying cycles initiated a hydromorphic soil forming process: ferrolysis, based on iron reduction producing alkalinity under anaerobic conditions, and iron oxidation producing acidity in aerobic conditions. Its intensity was enhanced at the top of thick clay-rich B-horizons in the center of cryogenic structures. The polygonal soil structure favored the evacuating of soil water and alkalinity. Within one century, such recurrent alternating redox conditions have led to clay destruction, removal of iron, strong bleaching of the E horizon and formation of abiotic Fe-rich pedofeatures at depth. In addition, between anaerobic clay-rich B and aerated E or C horizons, the contrasting hydrodynamic conditions enhanced manganese (Mn) oxidizing fungal activity and the formation of biotic Mn-rich pedofeatures. Both types of pedofeatures trapped metal pollutants in deep soil horizons. In our work, the impacts of centenary anthropogenic activity were amplified by millenary cryogenic structures, acting together to promote fast soil dynamics, within a few decades. [ABSTRACT FROM AUTHOR]

A carbon steel container including nuclear glass has been altered for 2 years in Andra’s Underground Research Laboratory to simulate the behaviour of waste package.Post-mortemanalyses at different scales (macro–micro–nano) have been performed to identify neoformed phases on iron corrosion products (ICP) and in the glass alteration layer (GAL). It has been shown at nanometric scale that important quantities of iron and silicon were found in the GAL and in the ICP respectively. Using a comparative approach with phyllosilicate references, STXM, at Si-K edge, suggests presence of trioctahedral species in the GAL and in ICP. Relevant fits of the STXM spectra are obtained with a Fe-rich chlorite for the nanostructured GAL, which could be formed according to chloritisation mechanism. This paper is part of a supplement on the 6th International Workshop on Long-Term Prediction of Corrosion Damage in Nuclear Waste Systems. [ABSTRACT FROM PUBLISHER]

Two experimental mockups were operated for one year at 70°C to study the corrosion of C-steel and alteration of AVM glass surrounded by Cox claystone. Only one system included cement-bentonite grout (CBG). Nanometer-scale analyses (TEM, XANES) examined the glass/C-steel interface to assess CBG's effects. The most notable difference was the presence of a nanometric magnetite layer on the C-steel surface in the CBG system. This layer, promoted by the slightly alkaline pH (8–10) solution influenced by CBG, could act as a passivating barrier, potentially mitigating corrosion, although corrosion rates showed no significant differences over one year. A 5 µm-thick sodium-depleted gel layer of disordered SiO2 formed on AVM glass in both systems, with similar porosity (14–20 nm). The open porosity may limit the gel's protective capacity. However, glass alteration rates decreased over time due to passivation mechanism primarily driven by reduced diffusion through the gel layer, with chemical affinity playing a lesser role. Secondary phases (Si-Fe-O, Si-Mg-O) were detected only in the CBG system, likely originating from the claystone or CBG rather than the glass itself. These findings indicate that CBG had little effect on AVM glass alteration but may enhance long-term C-steel corrosion resistance through magnetite layer formation. [ABSTRACT FROM AUTHOR]

This contribution aims to define an analysis procedure for abnormal deposits in human tissues starting fromin vivo characterization, down to the nanoscale using major instrumentation. Such an integrated approach is based on recent literature, but particularly on our research over the last twenty years on pathological calcifications. To this end, we begin by describing four successive analytical steps, on the injury site or physician's surgery, at the hospital, at a typical physicochemical laboratory, and finally at a large scale (possibly multinational) facility. For the first step, we present various techniques which can be implemented on portable instruments. For the second step, commercial analytical setups are used. In a physicochemical laboratory, prototype or commercial setups are used and finally on large scale instruments, characterization techniques with better spatial resolution and/or higher sensitivity or techniques specific to synchrotron radiation are employed. [ABSTRACT FROM AUTHOR]

Highlights: [•] In situ structural characterisation with XAS and XRD during electrochemical reduction. [•] Structural identification of phases formed during the wetting stage of iron AC. [•] Understanding the reduction and reoxidation processes during the wet–dry cycle of iron AC. [Copyright &y& Elsevier]

In the context of the cultural heritage, a methodology based on field and laboratory approaches is developed for studying the long-term corrosion of iron. Moreover it has been adapted to the study of archaeological artefacts buried in anoxic soils in the specific case of in situ preservation. The environmental parameters are determined on the archaeological sites and artefacts are collected and characterized using complementary multi-scale techniques. Moreover, laboratory experiments are performed to locate the reaction sites inside the corrosion layer and to identify its electronic properties. The results allow estimation of a low corrosion rate for iron buried in an anoxic soil (under 2 μm/year) and the proposal of a mechanism based on a decoupling of the anodic and the cathodic sites. Then a diagnosis of the alteration state of the samples is established. [ABSTRACT FROM AUTHOR]

We present the results of metallographic, elemental, and lead isotope analyses of one slag and 27 copper-base artefacts from northern Vietnam. These artefacts come from four sites: Dai Trach, Thành Dên, Gò Mun, Xuân Lâp and are attributed to the Đồng Đậu (ca. 1300–1000 BC), Gò Mun (ca. 1000–700 BC), and Đông Sơn (ca. 700 BC–100 AD) cultures, the two former being Bronze Age (18 samples) and the latter Iron Age (10 samples). Twenty-two of the samples have as-cast microstructures, with one having been quenched, three evidencing working and annealing, and one too corroded to tell. Despite variable corrosion levels, all metal samples are identified as bronzes, rather than copper, though seven are leaded bronzes. All the leaded alloys are Iron Age, which is typical for the region. Lead isotope results were notable, in that none of the study samples is consistent with the known prehistoric Southeast Asian copper production signatures, an unusual occurrence in recent regional provenance research. There is some compatibility with Thai Bronze Age copper-base artefacts, but generally it seems there was only weak overlap in exchange systems between northern Vietnam and southern Mainland Southeast Asia, with northern Laos as a possible frontier zone. Further archaeometallurgical prospection and characterisation in northern Vietnam are needed to identify primary production loci, but sources in the southern Chinese provinces of Yunnan, Guangxi, and Guangdong are also probable. [ABSTRACT FROM AUTHOR]

Corrosion experiments were performed on two metallic substrates, a ferritic–pearlitic steel (P285NH) and a ferritic one (Armco), in silicate environment during 30 days at 120°C. Corrosion products were characterized in terms of morphology (scanning electron microscope and transmission electron microscopy), composition (energydispersive X‐ray spectroscopy) and structure (µ‐Raman, selected area electron diffraction, X‐ray absorption near edge structure). Results show a nanometric inner layer made of compact and adherent nanocrystallized magnetite with, locally a thickness up to several micrometers due to the metal microstructure. An outer layer of Fe‐rich phyllosilicate, smectite and serpentine, more porous than the inner one and poorly adherent is observed around both the samples. [ABSTRACT FROM AUTHOR]

• Use of Scanning Auger electron microscopy to analyze insulating surfaces. • Creation of a new Si-KLL Auger database of reference spectra obtained on iron-phyllosilicate. • Multi-technical characterization (Auger, TEM) to identify iron-silicate. • Crystallized Fe-rich serpentine detected in glass/iron/claystone system altered at 90°C for 2 years in contact with COx water. In the context of high-level radioactive wastes (HLW) storage, long term alteration of glass and corrosion of metallic containers leads to the formation of sub-micrometric phyllosilicate phases in the iron Corrosion Product Layer (CPL). The nature of these phases, their properties (porosity, electronic, passivation...) and their spatial distribution must be identified to determine their exact role in the iron corrosion process and to efficiently predict the long-term alteration of nuclear wastes package. In this work, the capabilities of localized Auger spectroscopy, combining surface chemical determination and high spatial resolution, to characterize these phyllosilicate phases is presented. In the present context, the main challenge to overcome was the insulating character of the different compounds and samples, presenting a real disadvantage for Auger implementation. A specific experimental protocol had to be developed to enable acquiring exploitable spectra at sufficiently high resolution to obtain identifiable fingerprints. The main Si-KLL Auger transition of different types of phyllosilicates representative of those encountered in the CPL of the glass-iron systems was acquired to determine if different chemical signatures and chemical shifts could be observed in function of the structure of reference phyllosilicates phases. Indeed, the Si-KLL kinetic energy position value of the phyllosilicate increases with the structure according the following order: smectite group < chlorite group < serpentine group and different line shapes are observed. The significant contribution of the present study relies on the achievement of analyzing such insulating materials by Auger at nanometric scale using a new generation Auger nano-probe (spot size around 12 nm) without drastic preparation requirements, enabling to constitute a Si-KLL Auger data base of phyllosilicates. Thanks to this preliminary analytical approach, the Si-KLL fingerprint measured in the CPL of the glass/iron system altered in an anoxic reactor at 90 °C in synthetic Callovo-Oxfordian (COx) clay-based groundwater solution could be identified as serpentine phyllosilicate. Transmission electron microscopy (TEM) analysis was also used to characterize phyllosilicate and reinforce the AES approach identification, confirming the presence of serpentines. [ABSTRACT FROM AUTHOR]

Li (7−3×) Al x La 3 Zr 2 O 12 (LLAZO) Al-doped garnets display high ionic conductivity in the range of ~ 10 −4 S.cm −1 at room temperature and are thus envisioned for future solid-state batteries. In this study, LLAZO powders with two doping levels were synthetized using a solid-state route and sintered using Spark Plasma Sintering (SPS). Both pristine and SPS crushed pellet powders were investigated using X-Ray Diffraction (XRD) confirming the formation of the most conducting cubic phase. Ionic conductivity measurements were performed using electrochemical impedance spectroscopy. Li and Al distributions among available sites were identified using Magic Angle Spinning (MAS) Nuclear Magnetic Resonance (NMR) experiments, and Li mobility was explored using 7 Li static wideline NMR spectroscopy. Results show that SPS treatment, beyond producing highly densified pellets, mainly modifies Al distribution and strongly impacts the bulk Li + mobility. [ABSTRACT FROM AUTHOR]

Coupons of carbon steel were corroded in situ in anoxic clay porewater under slightly alkaline conditions. Sample damage was less than 1 μm for 9 months at 85 °C only, and corrosion interfaces were covered by a thin, protective layer of Fe-silicate. The damage was more significant for samples exposed to room temperature transients (up to 38 μm for two years), and the long-term surface differentiated in cathodic (Fe-silicate covered) areas and anodic crevices filled with siderite, chukanovite, β-Fe 2 (OH) 3 Cl, and covered by tubercles. Sulfide compounds were detected, and were related to the metabolism of sulfate-reducing prokaryotes detected by microbiological techniques. [ABSTRACT FROM AUTHOR]

Long-term confinement of nuclear waste is one of the main challenges faced by the nuclear industry. Fission products such as 90 Sr and 137 Cs, both β − emitters known to induce serious health hazards, represent the largest fraction of nuclear waste. Cement is a good candidate to store them, provided it can resist the effects of irradiation over time. Here, we have investigated the effects of β − decay on cement by performing electron irradiation experiments on different samples. We show that H 2 production in cement, the main effect of water radiolysis, depends strongly on composition and relative humidity. First-principles calculations indicate that the water-rich interlayer regions with Ca 2+ ions act as electron traps that promote the formation of H 2 . They also show that holes localize in water-rich regions in low Ca content samples and are then able to participate in H 2 production. This work provides new understanding of radiolysis effects in cements. [ABSTRACT FROM AUTHOR]

To investigate the fate of nuclear waste in geologic repositories, corrosion experiments were performed on a ferrito‐pearlitic (P285–NH) and a ferritic steel (Armco) in a synthetic solution representing the Callovo-Oxfordian porewater for 3-months at 120 °C. Corrosion product layers (CPL) were characterized from micro to nanoscale. Local corrosion areas of higher thicknesses were composed of siderite layers with different nano-morphologies, iron silicate, iron sulphate and magnetite. Their formation could be due to local pH variation, but also on metal microstructure (phases location and morphology). Differences in corrosion progress are suggested to be mainly related to differences in porewater chemistry and cathodic sites. • Fe corrosion in Cox porewater leads to Fe carbonate, Fe silicate, Fe sulphate and Fe oxide formation. • First step of Fe corrosion in Cox porewater is the formation of a Ca-siderite bi-layer. • Fe corrosion in Cox porewater continues locally at the M/CPL interface. • Local changes in the porewater chemistry led to a switch from a carbonate system to a mixed system. [ABSTRACT FROM AUTHOR]

The corrosion interface of low-alloy carbon steel (C-steel) coupons (P235, ferrite-pearlitic with a columnar microstructure) reacted in clay porewater seeping in a test chamber in situ in the Callovo-Oxfordian formation of the Meuse-Haute Marne Underground laboratory (France) was probed by microscopic and microspectrocopic techniques. Two series of samples were investigated, with extensive and limited corrosion, respectively. For extensively corroded coupons, several layers of inner corrosion products were observed. The innermost layer was made of Cl-rich Fe (hydr)oxide, later evolving to form a massive β-Fe 2 (OH) 3 Cl unit close to C-steel, and sometimes crossed by magnetite ribbons sticking to cementite lamellas, or by patches of green rust. The second inner layer was made of veinlets of Fe hydrated silicate with a sponge-like morphology, a molecular-scale structure reminiscent of clay minerals, and containing nodules of siderite and chukanovite. These (hydroxy)carbonate solids sometimes merged to form a massive layer close to the trace of the original surface. The layers external to this original surface were discontinuous and made of successively Ca-doped siderite (ankerite), Fe sulfide, S‐rich Fe silicate, and finally pyrite nodules and ankerite. For the samples with limited damage, no β-Fe 2 (OH) 3 Cl layer was observed, siderite or chukanovite were in close contact with metal, sometimes with interfacial magnetite, and the veinlets of Fe hydrated silicate were less developed. Only external layers of Fe sulfide and ankerite were observed. This suggests that these slightly corroding samples were in fact confined. Evidence for microbial activity was obtained in the form of a Fe sulfide fringe mixed with ankerite. Microbial activity may have induced some local heterogeneity in corrosion processes, e.g. by changing local pH conditions at mm-scale. [ABSTRACT FROM AUTHOR]

Fossil-bearing shale specimens that include sulfides are chemically reactive and sometimes also mechanically fragile. This decay is provoked by iron sulfate efflorescence resulting from the oxidation of sulfide compounds. The processes underlying these degradations are poorly known, thus impeding the elaboration of curative or preventive treatments. The present contribution aims to identify the origin of museum specimen alterations. It focuses on the Flouest collection housed at the Muséum national d’Histoire naturelle (MNHN, Paris, France) and originating from the Autun Basin (Saône-et-Loire, France; Permian). To evaluate the alteration of MNHN specimens, it appeared necessary to compare their composition with that of unaltered shale so as to identify chemical changes occurring during ageing. Therefore new material was collected in the Autun Basin, among others on the locality of Muse that corresponds to the same lithostratigraphic unit than that of the MNHN specimens. This work is divided in three parts. The two first, presented elsewhere, deal with the composition of the shale matrices and led to the conclusion that these matrices could not account for the large iron(II) sulfate efflorescence provoking damage on the MNHN specimens. The last part of this work, presented here, focus on artificial ageing experiments performed on new shale material. Most of the alterations observed on artificially aged samples correspond to dispersed crystals of calcium sulfate (gypsum). Similar crystals may be found on MNHN specimens, but they are relatively few and sporadically distributed. They are thus considered as damage of secondary importance with respect to iron sulfate efflorescence. These latter could be reproduced on three samples only (upon the 142 aged samples). They were also found on a coprolite and on a wood remain that had got severely damaged in ambient conditions within a few months after their excavation. On all these samples iron sulfate had grown on brownish layers consisting in crystals of framboidal pyrite (1 to 3 μm) and eventually sulfur (20 to 50 μm). These brownish layers are associated to thin maceral layers probably because of bacterial activity: during fossil diagenesis, bacteria need organic matter for their metabolism to produce hydrogen sulfide, a precursor of sedimentary pyrite formation. Most of the damaged specimens of the Flouest collection show as well a thin maceral layer nearby iron(II) sulfate efflorescence. On one of them, this layer is particularly thick. It corresponds to vitrinite and shows in some areas a brownish aspect. The topology of this surface (observed with scanning electron microscopy) shows numerous small holes (< 2 μm) and large holes (10–20 μm). This morphology is compatible with a former occurrence of isolated grains and aggregates of framboidal pyrite. These observations suggest that iron sulfate efflorescence was provoked by the oxidation of framboidal pyrite forming deposits on maceral layers. Because of their brownish aspect, they can easily go unnoticed by naked eye. This work will also help to improve visual assessment of currently collected fossils so as to identify the most reactive ones. [ABSTRACT FROM AUTHOR]

A study of five diamonds containing mineral and fluid inclusions, selected among forty-nine specimens from the Cullinan Mine, South Africa, was carried out to better document the origin and formation of N-absent B-poor (type IIb) diamonds. The combination of several in-situ non-destructive techniques was used to identify the mineralogy and the chemical composition of primary and secondary inclusions. These include breyite, larnite, graphite, Fe-Ni-Cu native metallic alloys, sulfides of the pyrrhotite group, Ni-rich oxide and potential hydrous ferric sulfates. A common and abundant hydrous fluid containing H 2 O + CH 4 was also identified. From the various observations, we suggest that these type IIb diamonds grew in an aqueous oxidized fluid reacting with a reduced mantle characterized by low oxygen fugacity. Remnant pressures recorded in primary breyite by Raman shifts and XRD measurements enabled the calculation of minimal entrapment pressures of inclusions using elastic geothermobarometry. Applying pressure corrections caused by elastic relaxation, minimum trapping pressures from 4.9 GPa to 5.6 GPa were calculated, suggesting lithospheric depths consistent with the occurrence of numerous graphite inclusions. The association of breyite and larnite, which is often considered as an indicator of sublithospheric origin, also occurs at pressures of 6 GPa or lower in a H 2 O-rich and carbonate/Ca-rich environment. The B-poor and N-absent features of type IIb diamonds do not require the classic subduction-related model of their formation. Whereas high-pressure minerals would host boron in cold subducting slabs, slabs are also important carriers of nitrogen into the deep mantle, with this latter element mostly absent in these diamonds. In our alternative model, the mantle is proposed as an alternative source of boron, whereby metallic alloys or N speciation between fluid and melt would still prevent the incorporation of nitrogen, leading to the expression of the blue, boron-related and N-absent features of type IIb diamonds. The observed mineralogical assemblage neither proves sublithospheric origin nor does it exclude lithospheric depths of formation for these diamonds. Hence, we propose that type IIb diamonds form in a mantle continuum, from sublithospheric to lithospheric depths. • N-free type IIb blue diamonds from Cullinan Mine studied for mineral/fluid inclusions. • A unique association of C graphite + H 2 O + CH 4 fluids and Fe Ni alloys has been found. • Minimum trapping pressures of 4.9–5.6 GPa from breyite suggest a lithospheric origin. • Type IIb grows at low f O 2 at any mantle depth in aqueous fluids ± metal alloys. • Metals prevent nitrogen trapping while boron might sourced from the mantle. [ABSTRACT FROM AUTHOR]

Chemical and mineralogical properties of solids formed upon free corrosion of two iron probes (one massive iron rod, and one model overpack made by two pipes covering the ends of a glass rod) in saturated clay rock (Callovo-Oxfordian formation, East of Paris Basin, France) at 90 °C over two years were investigated by microscopic and spectroscopic techniques (X-ray tomography, scanning electron microscopy coupled with energy-dispersive X-ray analysis, Raman microspectroscopy, micro-X-ray diffraction, and micro-X-ray Absorption Fine Structure spectroscopy). The corrosion rate of the massive rod was monitored in situ by electrochemical impedance spectrometry, and found to decrease from about 90 μm/year during the first month of reaction, to less than 1 μm/year after two years. X-ray tomography revealed the presence of several fractures suggesting the presence of preferential flow and diffusion pathways along the iron samples. Microscopic observations revealed similar corrosion interfaces for both samples. Corrosion heterogeneously affected the interface, with damaged thickness from ∼0 to 80 μm. In extensively damaged areas, an inner discontinuous layer of magnetite in contact with metal, an intermediate chukanovite (Fe 2 CO 3 (OH) 2 ) layer (only when magnetite is present, and only for the overpack), and an outer layer of poorly ordered Fe phyllosilicate were observed. In areas with little damage, only the Fe-silicate solids are observed. The clay transformation layer is predominantly made of ankerite ((Fe,Ca,Mg)CO 3 ) forming a massive unit near the trace of the original surface, and intermixed with clay minerals towards the bulk matrix. The average thickness of oxidized iron, as measured by the average of distances from the original to the final metal surface, was 13 ± 1 and 15 ± 1 μm for the massive rod and the micro-overpack, respectively. The corresponding Fe amount is about twice the amount of Fe present in the corrosion products. Thus a significant Fe fraction migrated in the nearby clay, likely as Fe (II) , and could act as a significant buffer of the electrochemical potential. [ABSTRACT FROM AUTHOR]

Abstract: This article is focused on the formation of hydride blisters in zirconium alloys an experimental and theoretical standpoint, and their characterization in terms of morphology, hydrides crystallographic phases, hardness and hydrogen concentration. An experimental setup was developed to grow hydride blisters on pre-hydrided Zircaloy-4 cladding tubes by thermo-diffusion. The thermal conditions were optimized based on thermo-diffusion calculations, that take into account the hysteresis in the hydrogen solubility limit, to obtain a high blister growth rate. Micro-X-ray Diffraction (XRD), nano-hardness and Elastic Recoil Detection Analysis (ERDA) showed that the blisters contain a hydrogen gradient, with pure -hydride phase close to the external surface over one third of the blister depth. Thermo-diffusion calculations showed these half thickness blisters should grow in only a few days in PWR conditions. Eventually, the Diffusion Equilibrium Threshold (DET) was defined as a criterion that limits the blister growth, and emphasizes that the hysteresis in the hydrogen solubility limit in zirconium must be taken into account to model hydrogen thermo-diffusion in zirconium alloys. [Copyright &y& Elsevier]

Highlights: [•] Laboratory experiments were performed on a glass simulating archeological artifacts. [•] Experimental conditions reproduced in situ anoxic and clay-type environment. [•] The effects of siderite and metal iron on glass leaching were investigated. [•] Siderite led to a moderate and transient effect limited by silica sorption. [•] With metal iron, glass corrosion is durably sustained by the precipitation of Fe-silicates. [ABSTRACT FROM AUTHOR]

Abstract: The production of molecular hydrogen by gamma radiolysis and vacuum ultra violet photolysis of dried and hydrated nanoporous titania and zirconia nanoparticles has been studied. The nanoparticles were prepared as free standing films using a surface sol-gel process on cellulose. A significant hydrogen production was observed for both TiO2 and ZrO2 in vacuum ultra violet or gamma irradiation. This production could be optimized by controlling the amount of water and by introducing hydroxyl radical scavengers in the irradiated systems. The mechanism underlying hydrogen production seems qualitatively different in gamma and in vacuum ultra violet (VUV) irradiation. [Copyright &y& Elsevier]

Abstract: Glass–iron–clay setups were reacted at 90°C for 6–18months to investigate the coupled interactions between glass alteration, Fe corrosion and clay transformation. The reacted interfaces were probed at the microscopic level using complementary characterization methods (scanning electron microscopy coupled with energy-dispersive X-ray analysis, micro-Raman spectroscopy, micro X-ray diffraction, micro X-ray fluorescence spectroscopy, and micro X-ray absorption near-edge structure spectroscopy). The 10-μm thick Fe foil was fully corroded within 10months, exposing glass to the pore solution. Iron corrosion led to the formation of a layer containing mostly magnetite, siderite and Fe-rich phyllosilicates with one tetrahedral and one octahedral sheet (TO) or two tetrahedral and one octahedral (TOT) sheet per layer. The clay in contact with this corrosion layer was enriched in siderite (FeCO3). Glass alteration resulted in the formation of a gel layer whose thickness increased with reaction time (from 20μm after 6months to 80μm after 18months) and a thin layer of secondary precipitates that concentrated lanthanides, P, and Mo. Assuming conservative behavior of Zr, the Si molar concentration in the gel is about 57% that in the glass. Glass dissolution remained at a rate close to the initial dissolution rate r 0. The data are consistent with glass dissolution sustained by the uptake of dissolved Si and charge-compensating cations on secondary (corrosion) products, thus maintaining the gel porosity open and facilitating the leaching of easily soluble elements. [ABSTRACT FROM AUTHOR]

Abstract: Corrosion patterns on samples taken on binder and rebars from two buildings, respectively, aged of 46 and 260years old have been characterised by coupling different analytical methods at microscopic scale. Different corrosion patterns have been observed. The first one is constituted by the initial mill scale made of wustite, magnetite and hematite. The second one contains remains of this mill scale embedded in phases formed after aqueous corrosion: oxyhydroxides as goethite or lepidocrocite containing marblings of ferrihydrite, maghemite and magnetite. On the thicker and older layers, marblings were only constituted of magnetite and maghemite. It is proposed that the structural evolution of the pattern and their marbling is linked to wet/dry cycles and/or pH condition evolution during the corrosion processes. [ABSTRACT FROM AUTHOR]

To understand the process governing iron corrosion in clay over centuries, the chemical and mineralogical properties of solids formed by free or anodically activated corrosion of iron in water-saturated clay at 90 °C over 4 months were probed using microscopic and spectroscopic techniques. Free corrosion led to the formation of an internal discontinuous thin (<3 μm thick) magnetite layer, an external layer of Fe-rich phyllosilicate, and a clay transformation layer containing Ca-doped siderite (Ca0.2Fe0.8CO3). The thickness of corroded iron equaled ∼5-7 μm, consistent with previous studies. Anodic polarization resulted in unequally distributed corrosion, with some areas corrosion-free and others heavily corroded. Activated corrosion led to the formation of an inner magnetite layer, an intermediate Fe2CO3(OH)2 (chukanovite) layer, an outer layer of Fe-rich 7 Å-phyllosilicate, and a transformed matrix layer containing siderite (FeCO3). The corroded thickness was estimated to 85 μm, less than 30% of the value expected from the supplied anodic charge. The difference was accounted for by reoxidation at the anodically polarized surface of cathodically produced H2(g). Thus, free or anodically activated corroding conditions led to structurally similar interfaces, indicating that anodic polarization can be used to probe the long-term corrosion of iron in clay. Finally, corrosion products retained only half of Fe oxidized by anodic activation. Missing Fe probably migrated in the clay, where it could interact with radionuclides released by alteration of nuclear glass. [ABSTRACT FROM AUTHOR]

We report on the capacity of AMS radiocarbon dating to play a decisive role in fighting against the illicit trade in art. In the framework of a current police investigation, where previously unseen paintings were discovered in a restorer's workshop by the French Central Office for the Fight against Illicit Trafficking in Cultural Property (OCBC), we demonstrated that two paintings alleged to be by Impressionist and Pointillist artists had in fact been painted recently. Our results were based on the excess of 14C derived from atmospheric nuclear tests detected in the fibers used to make the canvas. By combining AMS 14C absolute dating and the fine precision of the post-bomb atmospheric calibration curve, we established a clear chronological context for the production of these forgeries. 14C content of the fibers revealed that the canvases were manufactured in 1956-1957 or, more likely, after 2000. As a result, absolute dating proves unambiguously that the Impressionist and Pointillist paintings are forgeries since they were not painted at the beginning of the 20th century by the alleged artists, who died in the 1940s. [ABSTRACT FROM AUTHOR]

Li-air batteries possess higher specific energies than the current Li-ion batteries. Major drawbacks of the air cathode include the sluggish kinetics of the oxygen reduction (OER), high overpotentials and pore clogging during discharge processes. Metal–Organic Frameworks (MOFs) appear as promising materials because of their high surface areas, tailorable pore sizes and catalytic centers. In this work, we propose to use, for the first time, aluminum terephthalate (well known as MIL-53) as a flexible air cathode for Li-O2 batteries. This compound was synthetized through hydrothermal and microwave-assisted routes, leading to different particle sizes with different aspect ratios. The electrochemical properties of both materials seem to be equivalent. Several behaviors are observed depending on the initial value of the first discharge capacity. When the first discharge capacity is higher, no OER occurs, leading to a fast decrease in the capacity during cycling. The nature and the morphology of the discharge products are investigated using ex situ analysis (XRD, SEM and XPS). For both MIL-53 materials, lithium peroxide Li2O2 is found as the main discharge product. A morphological evolution of the Li2O2 particles occurs upon cycling (stacked thin plates, toroids or pseudo-spheres). [ABSTRACT FROM AUTHOR]

Applying operando investigations is becoming essential for acquiring fundamental insights into the reaction mechanisms and phenomena at stake in batteries currently under development. The capability of a real-time characterization of the charge/discharge electrochemical pathways and the reactivity of the electrolyte is critical to decipher the underlying chemistries and improve the battery performance. Yet, adapting operando techniques for new chemistries such as metal-oxygen (i.e. metal-air) batteries introduces challenges in the cell design due notably to the requirements of an oxygen gas supply at the cathode. Herein a simple operando cell is presented with a two-compartment cylindrical cell design for NMR spectroscopy. The design is discussed and evaluated. Operando 7Li static NMR characterization on a Li–O 2 battery was performed as a proof-of-concept. The productions of Li 2 O 2 , mossy Li/Li dendrites and other irreversible parasitic lithium compounds were captured in the charge/discharge processes, demonstrating the capability of tracking the evolution of the anodic and cathodic chemistry in metal-oxygen batteries. [Display omitted] • A simple operando NMR cell dedicated for the metal-air batteries is introduced. • First reported operando 7Li NMR measurement on a Li–O 2 cell. • Important parasitic products are evidenced along cycling. [ABSTRACT FROM AUTHOR]

The application of lead isotope-based provenance analysis in Southeast Asia over the last decade has strongly suggested a central role was played by the Lao PDR in regional copper production exchange networks for approximately 1500 years. The Vilabouly Complex, in central Lao's Savannakhet Province, has revealed major copper mining and smelting sites dated to the regional Iron Age (c. 400 BC – AD 500) and possibly Bronze Age (c. 1000 - 400 BC). Metallurgical practices at the Vilabouly Complex, and indeed for all of the Lao PDR, are unknown, and the propose of this paper is to provide a comprehensive analytical study of the Vilabouly Complex metal assemblage, including 60 copper-base artefacts of multiple typologies. Cut samples of these were subjected to morpho-stylistic, metallographic (OM), elemental (XRF, SEM-EDS) and lead isotope analyses (MC-ICP-MS) in order to reconstruct the range of forms, metalworking materials, techniques (alloying, casting and post-casting treatments) used at the Vilabouly Complex. The results revealed an assemblage composed of copper, bronze and leaded bronze alloys, with a majority consistent with the lead isotopic signature for the Vilabouly Complex copper. The consistent geochemical and technological signature of the majority of artefacts strongly corroborates the extensive onsite production evidence, and fits with the burgeoning regional copper-base metals database for copper metal demand being sated in large part by Lao PDR supply. • 60 metal artefacts evidence copper, bronze and leaded bronze compositions. • Type classes (e.g. ingots, tools, ornaments) co-vary closely with alloy classes. • LIA shows very high proportion of consistency with Vilabouly Cu signature. • High resolution LIA shows slight differences in mineral exploitation over time. • Analysis suggests on-site production of ge (halberds) of Han typology. [ABSTRACT FROM AUTHOR]