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Recent developments in synchrotron storage ring technology, insertion device design and X-ray optics provide polarized photon beams with unprecedented intensity and brilliance on a microscopic area. Various arrangements allow micrometer size hard X-ray beams with enough flux to undertake elemental mapping of trace elements then easily associated with micro-diffraction or micro-extended X-ray absorption fine structure studies on the very same sample region of interest. These analytical possibilities and the sensitivity and accuracy of the achieved analysis can complement or surpass other available instrumental micro-analytical methods. Such microprobes are becoming a very interesting tool for material characterization.

The goal of this work is to present the current state of the X-ray Fluorescence Computed Microtomography. The advantages of both the experimental techniques and the data processing (the ESRF ID22 beamline facilities [1]) arc considered. The latter one includes the spectra treatment, reconstruction of the atomic density distribution function of the element under consideration and/or calculation of the element effective concentration map and calculation of the element ratio maps. Possible ways of estimating the space resolution and the accuracy are discussed. Results of the tomographic investigation of the NWA817 meteorite micro-grain are presented.

Synchrotron X-ray fluorescence (SXRF) analysis of individual fluid inclusions was performed on a suite of samples collected above and beneath a well-documented connectivity barrier of the Dunbar oil field, North Sea. The fluid inclusion analyzed consists of two phases (liquid + vapor), low salinity aqueous brines lining overgrowth zone of detrital quartz that formed during secondary silicification of the host sandstone. SXRF measurements indicate that the inclusion fluid contains a large variety of major and trace elements including CI, K, Ca, Ti, V, Cr, Mn, Fe. Co, Ni, Cu. Zn, Ga, Se, Br, Rb, Sr. Zr, Nb, Cd, Ba, Pb. Chemical mapping of a large inclusion (30 μm) together with element correlation diagrams show that, with the exception of Ca, Sr, Br and in lesser extent Zn, which display an homogeneous distribution throughout the inclusion, most elements show small-scale distribution heterogeneities that are best interpreted in terms of infra-μm solid phases suspended in the fluid phase. Calculated concentration estimates are critically dependent of the interpretation made for the origin of these solid phases (heterogeneous trapping vs. precipitated from the ambient inclusion fluid).

X-ray imaging techniques at the best spatial resolution and using synchrotron facilities are put forth as powerful techniques for the search of small life forms in extraterrestrial rocks under quarantine conditions. Absorption and fluorescence X-ray microtomographies on sub-millimeter silicate assemblages inside a container reveal the mineralogical microenvironments were life should be looked for in priority. Limitations with respect to bacterial detection are due to the difficulties to obtain information about light elements ($Z \leq 14$), major constituents of biological and silicate samples. The X-ray signature of a “present" bacteria on a silicate surface was defined by X-ray mapping, out of a container, as coincident micrometer and oval zones having strong P and S fluorescence lines (S-fluorescence being slightly lower than P-fluorescence) and an amino-linked sulfur redox speciation. The detection of a single cell along with new procedures to calculate tomographic views will allow considerable improvements of 3D detection of life by X-ray techniques.

A decoration figure of a ritual bronze vase from Canas de Senhorim (Portugal) was analysed by Energy Dispersive X-Ray Fluorescence (EDXRF) spectrometry and Synchrotron Induced X-Ray Fluorescence (SXRF) microprobe spectrometry. This artefact, a Centaurusconstitutes the first evidence for a possible Roman occupation of this region of Central Portugal and it is also one of the very few artefacts of this type ever found. The determination of the Centaurusalloy composition will be important in me further comprehension of the metallurgical technologies used by the Romans in this region. EDXRF analysis of the corroded surface were made using the monochromatic radiation emitted by Ag and Gd secondary targets excited by a Rh X-ray tube at 35kV and 57 kV, respectively. SXRF experiments were carried out both on the corroded surface and on a small clean area of the artefact, using both monochromatic and polychromatic excitations with 32 keV and 12 keV radiations. EDXRF results allowed the determination of the alloy bulk composition. The SXRF comparative analysis between the clean and corroded areas evidences the surface enrichment in Sn and establishes the composition of the original alloy. The Centaurusalloy is a bronze with rather high Pb content, which is characteristic of the Roman decorative artefacts.

The pathogenesis of two neurodegenerative diseases i.e. Parkinson's Disease (PD) and amyotrophic lateral sclerosis (ALS) are still not known. It is supposed that disturbance of metal ions homeostasis may promote degeneration and atrophy of neurones. As a preliminary study. the quantitative and topographic elemental analysis of selected parts of human brain and spinal cord was performed using synchrotron microbeam-X ray fluorescence (μ-SXRF) technique. The samples were taken during the autopsy from patients with PD, ALS and from patients died due to non-neurological conditions events. X-ray fluorescence imaging showed that increased concentration of selected elements are observed in neurons perikarial parts in compare with surrounding area. Moreover, comparable analysis showed significant differences in accumulation of selected elements between the pathological and control cases. The investigations indicate that micro-beam of synchrotron radiation can be satisfactory applied for analysis of central nervous System tissue providing useful information about distribution and contents of elements at the single cell level.

The combination of Synchrotron X-Ray Fluorescence microprobe (SXRF) with other micro-analytical techniques based on accelerated particle beams. such as Rutherford Backscattering Spectrometry (RBS), and Particle Induced X-ray Emission (PIXE) enable to quantify SXRF results of thin biological specimens. The same specimens were analysed by both techniques. The average thickness calculated by RBS of discrete tissue regions in equivalent sample sections was used to normalise SXRF data. Analysing the same sample region with PIXE technique, simultaneously to RBS, can validate the methodology once it will enable to compare concentrations obtained for elements that are detected by both SXRF and PIXE. Major departures were found for the quantification of Ca and Ti. For Cr and Fe a good agreement was found between both micro-analytical techniques. Differences below 20% were obtained for the majority of the elements and samples analysed. The procedure can be applied to produce quantitative elemental maps and it will be advantageous to quantify toxic elements present at low concentrations in tissues, such as Cr, Ni and Pb, which can only be efficiently assessed by SXRF.

The fabrication and testing of planar refractive lenses made from diamond and silicon is reported. We obtained efficiencies up to 78% and 31% for diamond and silicon lenses, respectively. A FWHM of the line-focus down to 3 μm has been achieved for both types of lenses. Using two crossed silicon lenses in series 2-dimensional focusing has been demonstrated, resulting in a micro focus of 7*14 μm at 35 keV. This demonstrates the feasibility of silicon lenses for micro-focusing applications at extreme photon energies (above approx. 30 keV). Due to the unique physical properties of diamond, diamond lenses should be able to withstand the extreme flux densities expected at future X-ray free electron lasers (X-FELs). This makes diamond refractive lenses very promising candidates for applications at these 4thgeneration x-ray sources.

Fluorescence tomography is a non-destructive, non-invasive technique that provides information about the internai spatial distribution of each element that emits a detectable fluorescence signal from the measured slice of the sample. The reconstruction proMem for fluorescence tomography is much more difficult than it is for transmission tomography, due to the absorption of thé photons within the excitation and détection paths. The present work présents a reconstruction technique that is based on the SART (Simultaneous Algebraic Reconstruction Technique) algorithm, which has been modified in order to take into account absorption corrections. This technique has been applied to the analysis of individual waste fly ash particles of about 80-150 micron diameters, which have been scanned using an X-ray beam of V*H=2*5 pjn spot-size and placing an energy dispersive Si (Li) X-ray detector at 90 degrees to the incoming excitation beam. From previous scanning i-SRXRP measurements it is clear that the elemental distribution within individual fly ash particles is highly inhomogeneous but no information could be obtained on the location of the différent investigated elements (within/on the surface of the particle). On the other hand thé location of toxic elements within individual fly ash particles affects the possible fate of thèse elements during e.g. fly-ash recycling. Thus the aim of this study was to investigate the 2D interna) elemental distribution of the particles, with spécial attention to that of the toxic metals, such as Zn, Cd, Pb.

The penetration of liquid metals into the gain boundaries (GB) of solid metals in the absence of external stress is a process which, in the case of some specific couples, can lead to severe embrittlement ofthe solid. We present in this paper two synchrotron radiation (SR) X-ray imaging techniques, which are well adapted for the non-destructive bulk characterization of this type of phenomena. Synchrotron radiation X-ray micro-radiography was used to characterize the liquid metal penetration kinetics in the Al/Ga system. It was shown that this modern variant of absorption radiogaphy provides sufficient spatial and temporal resolution to observe the penetration of sub-micrometric liquid Ga films into the grain boundaries of Al bicrystals. Synchrotron radiation X-ray micro-fluorescence on the other hand is well suited for the element specific characterization of extremely dilute systems. At the expense of temporal and spatial resolution, this technique allows one to detect minute quantities of atoms, diffusing along the GB of solid metals.

La préservation dans certains contextes archéologiques des cheveux humains et des fibres animales est favorisée par leur transformation chimique au contact d'objets métalliques. Afin de mieux comprendre les phénomènes complexes mis en jeu, nous avons étudié expérimentalement la fixation de cations métalliques (Cu et Pb) dans des cheveux modèles à partir de différentes méthodes de caractérisation utilisant le rayonnement X synchrotron. Nous avons ainsi pu mettre en évidence la fixation spécifique d'une partie de ces cations au sein des lipides structurés du cheveu. La comparaison entre échantillons modèles et archéologiques apporte de nouvelles données concernant les premières étapes d'altération des cheveux archéologiques.

Voice over IP (VoIP) is very fast growing technology for the delivery of voice communications and multimedia data over internet with lower cost. Early technical solutions mirrored the architecture of the legacy telephone network. Now, they have adopted the concept of distributed cloud VoIP. These solutions typically allow dynamic interconnection between users on any domains. However, providers face challenges to use infrastructure in the best efficient and cost-effective ways. Hence, efficient scheduling and load balancing algorithms are a fundamental part of this approach, especially in presence of the uncertainty of a very dynamic and unpredictable environment. In this paper, we formulate the problem of dynamic scheduling of VoIP services in distributed cloud environments and propose a model for bi-objective optimisation. We consider it as the special case of the bin packing problem, and discuss solutions for provider cost optimisation while ensuring quality of service.

Abstract—A new olivine‐pigeonite ureilite containing abundant diamonds and graphite was found in the United Arab Emirates. This is the first report of a meteorite in this country. The sample is heavily altered, of medium shock level, and has a total weight of 155 g. Bulk rock, olivine (Fo79.8–81.8) and pyroxene (En73.9–75.2, Fs15.5–16.9, Wo8.8–9.5) compositions are typical of ureilites. Olivine rims are reduced with Fo increasing up to Fo96.1–96.8. Metal in these rims is completely altered to Fehydroxide during terrestrial weathering. We studied diamond and graphite using micro‐Raman and in situ synchrotron X‐ray diffraction. The main diamond Raman band (LO = TO mode at ˜1332 cm−1) is broadened when compared to well‐ordered diamond single crystals. Full widths at half maximum (FWHM) values scatter around 7 cm−1. These values resemble FWHM values obtained from chemical vapor deposition (CVD) diamond. In situ XRD measurements show that diamonds have large grain sizes, up to >5 μm. Some of the graphite measured is compressed graphite. We explore the possibilities of CVD versus impact shock origin of diamonds and conclude that a shock origin is much more plausible. The broadening of the Raman bands might be explained by prolonged shock pressure resulting in a transitional Raman signal between experimentally shock‐produced and natural diamonds.

The abnormalities of metallochemical reactions may contribute to the pathogenesis of Amyotrophic Lateral Sclerosis (ALS). In the present work, an investigation of the elemental composition of the gray matter, nerve cells and white matter from spinal cord tissues representing three ALS cases and five non-ALS controls was performed. This was done with the use of the synchrotron microbeam X-ray fluorescence technique (micro-SRXRF). The following elements were detected in the tissue sections: P, S, Cl, K, Ca, Fe, Cu, Zn and Br. A higher accumulation of Cl, K, Ca, Zn and Br was observed in the nerve cell bodies than in the surrounding tissue. Contrary to all other elements, Zn accumulation was lower in the white matter areas than in the gray matter ones. The results of quantitative analysis showed that there were no general abnormalities in the elemental accumulation between the ALS and the control group. However, for individual ALS cases such abnormalities were observed for the nerve cells. We also demonstrated differences in the elemental accumulation between the analyzed ALS cases.The abnormalities of metallochemical reactions may contribute to the pathogenesis of Amyotrophic Lateral Sclerosis (ALS). In the present work, an investigation of the elemental composition of the gray matter, nerve cells and white matter from spinal cord tissues representing three ALS cases and five non-ALS controls was performed. This was done with the use of the synchrotron microbeam X-ray fluorescence technique (micro-SRXRF). The following elements were detected in the tissue sections: P, S, Cl, K, Ca, Fe, Cu, Zn and Br. A higher accumulation of Cl, K, Ca, Zn and Br was observed in the nerve cell bodies than in the surrounding tissue. Contrary to all other elements, Zn accumulation was lower in the white matter areas than in the gray matter ones. The results of quantitative analysis showed that there were no general abnormalities in the elemental accumulation between the ALS and the control group. However, for individual ALS cases such abnormalities were observed for the nerve cells. We also demonstrated differences in the elemental accumulation between the analyzed ALS cases.

The combination of synchrotron-based X-ray absorption and fluorescence computed tomographies (CT) is a new method allowing a noninvasive and nondestructive determination of the three-dimensional (3D) mineralogy with micrometer resolution of sub-millimeter silicate grains, possibly stored in a silica holder. These CT were performed with beams of a few tens of keV from a third-generation synchrotron source on one olivine grain of the NWA817 Martian meteorite presenting a reddish alteration phase. The reconstructed sections show a network of fractures and a few micrometer-thick layers formed on one grain. The 3D facet orientation and the X-ray attenuation coefficient indicate that this grain is an Fo44±9olivine crystal. The fluorescence section reveals rims enriched in Fe (a major element) or depleted in Ca (a minor element). This CT combination shows that the micrometer-thick layer is preferentially formed on the (010) olivine face and has a lower density (3.5 ± 0.4 g/cm3) than the olivine, even though it is enriched in Fe. Its complex nano-petrography and the distributions of nanometer-sized voids and fractures in such a micrometer thick layer, first observed by scanning electron microscopy on focused ion-beam cuts, is not shown by CT. The precision presently achieved, although moderate, is sufficient to obtain a 3D semi-quantitative view of the mineralogy consistent with the one previously established by electron probe microanalyses (Sautter et al. 2002).

The combination of synchrotron-based X-ray absorption and fluorescence computed tomographies (CT) is a new method allowing a noninvasive and nondestructive determination of the three-dimensional (3D) mineralogy with micrometer resolution of sub-millimeter silicate grains, possibly stored in a silica holder. These CT were performed with beams of a few tens of keV from a third-generation synchrotron source on one olivine grain of the NWA817 Martian meteorite presenting a reddish alteration phase. The reconstructed sections show a network of fractures and a few micrometer-thick layers formed on one grain. The 3D facet orientation and the X-ray attenuation coefficient indicate that this grain is an Fo44±9olivine crystal. The fluorescence section reveals rims enriched in Fe (a major element) or depleted in Ca (a minor element). This CT combination shows that the micrometer-thick layer is preferentially formed on the (010) olivine face and has a lower density (3.5 ± 0.4 g/cm3) than the olivine, even though it is enriched in Fe. Its complex nano-petrography and the distributions of nanometer-sized voids and fractures in such a micrometer thick layer, first observed by scanning electron microscopy on focused ion-beam cuts, is not shown by CT. The precision presently achieved, although moderate, is sufficient to obtain a 3D semi-quantitative view of the mineralogy consistent with the one previously established by electron probe microanalyses (Sautter et al. 2002).

In-situ measurements of the amount of dissolution of carbonate minerals at high pressures (up to 3.6 GPa) and temperatures (up to 523 K) are reported. Using an externally heated diamond anvil cell (DAC) and synchrotron X-ray fluorescence (SXRF), the extent of dissolution of strontianite (SrCO3) has been followed as a function of time by monitoring the fluorescence of Sr cations in the fluid surrounding the crystal. This work demonstrates that Sr2+concentrations as low as 1000 ppm can be detected and measured in-situ in a DAC, using a forward transmission geometry. The preliminary data presented here indicate that this technique has high potential for determining solution composition in high-pressure and high-temperature geochemical studies.

This paper examines the application of virtual reality cues, generating the biofeedback effects of a real tiled floor, reported in [8], for gait improvement in Parkinson's Disease (PD) patients. A portable apparatus, comprising head and body-mounted 3-axis accelerometers, a wearable computer and see-through head-mounted display, creates a virtual tiled floor, responding to the patient's own dynamics. Performance of PD patients using the device improved (higher speed, longer stride) by about 30% on average.

Crystal spectrometry and absorption edge technique have the capability to overcome the gap in accuracy between experiment and theory in the strong field domain of QED. New results are presented which indicate the capacity of these methods to measure the energies of X-rays emitted by highly charged heavy ions at modern storage rings with a precision sensitive to second order corrections to the Lambshift in H-like very heavy ions.

The various application possibilities of microscopic x-ray fluorescence and associated methods for the characterization and provenance analysis of objects and materials of cultural heritage value are discussed by means of a number of case studies. They include the trace analysis of historic glass, the analysis of corroded coins and statues in bronze and silver and the study of inks on historical documents. These studies are conducted by means of micro-XRF instruments installed at synchrotron beamlines and by means of laboratory equipment, some of which is easily transportable to the museum or archaeological site where the objects of interest are located. Copyright © 2000 John Wiley & Sons, Ltd.

Speckle‐pattern correlation interferometry (SPCI) is a well established technique in the visible‐light regime for observing surface disturbances. It has found application in non‐destructive testing of materials, as well as in medicine. A method of performing SPCI in the X‐ray regime is presented. Instead of using surface reflection, small‐angle scattering is utilized. The simple geometry consists of one coherent X‐ray beam passing through two samples. The calculated resultant speckle field shows highly enhanced sensitivity to relative motion of the samples. Motions are simulated and their corresponding correlation patterns are calculated. Initial experimental results are presented.

A method is proposed for the determination of glyoxal and acetaldehyde in presence of each other in the oxidizing solutions of the glyoxal production. Glyoxal is determined by means of cyclohexylamine and acetaldehyde is calculated from the difference to a determination of total aldehydes by the hydroxylamine method. In the case of paraldehyde as starting material the total aldehyde contenthas to be determined by means of 2,4-dinitrophenylhydrazine.

Summary In the synthesis ofγ-acetopropanol by hydrogenation of methylfuran in acetonic solution unreacted methylfuran has been determined by bromatometry and acetone by oximation. A third unknown component could be identified as methyltetrahydrofuran. By a gas-chromatographic method all three components could be determined in presence of each other.

A novel semi-quantitative algebraic reconstruction technique for x-ray fluorescence tomography data sets is described and its use is demonstrated on laser-ablated resin samples. The experiments were performed at the ID22 beamline of the European Synchrotron Radiation Facility in Grenoble. The projections were collected using a parallel scheme using 22.5 keV x-rays at 4 µm resolution. The iterative algebraic reconstruction technique was used to calculate an elemental ‘effective’ concentration distribution. This ‘effective’ concentration is introduced for the first time and allows the attenuation of both the incident x-ray beam and the fluorescence to be included in the reconstruction procedure. Copyright © 2002 John Wiley & Sons, Ltd.