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Polycyclic aromatic hydrocarbons (PAHs) are persistent and widespread in the aquatic environment, causing potential hazards for human health. In this study, a superwetting and robust PES-PAA-ZrO2 nanofiltration membrane was proposed through surface modification for PAH removal with high efficiency. A ZrO2 coating was formed on polyethersulfone (PES) membrane surface through chemical bonding, thus the PES-PAA-ZrO2 membrane exhibited super-hydrophilicity, under-water oleophobicity, and excellent stability. In comparison with the original PES membrane, the water contact angle of the modified membrane was significantly decreased from about 50° to less than 10°, and quickly dropped to 0° within 1 s. This provided a much lower energy barrier for water permeation due to its super-high water affinity. The wastewater treatment efficiency was increased by about 4 times after modification with more than 90% of PAH rejection rate. The excellent robustness of PES-PAA-ZrO2 membrane was verified under various conditions, which gave the membrane practical potential for long-term operation.

Biomolecules with a broad range of structure and heteroatom-containing groups offer a great opportunity for rational design of promising electrocatalysts via versatile chemistry. In this study, uniform folic acid–Co nanotubes (FA–Co NTs) were hydrothermally prepared as sacrificial templates for highly porous Co and N co-doped carbon nanotubes (Co–N/CNTs) with well-controlled size and morphology. The formation mechanism of FA–Co NTs was investigated and FA–Co-hydrazine coordination interaction together with the H-bond interaction between FA molecules was characterized to be the driving force for growth of one-dimensional nanotubes. Such distinct metal–ligand interaction afforded the resultant CNTs rich Co–Nx sites, hierarchically porous structure and Co nanoparticle-embedded conductive network, thus an overall good electrocatalytic activity for oxygen reduction. Electrochemical tests showed that Co–N/CNTs-900 promoted an efficient 4e− ORR process with an onset potential of 0.908 V vs. RHE, a limiting current density of 5.66 mA cm−2 at 0.6 V and a H2O2 yield lower than 5%, comparable to that of 20% Pt/C catalyst. Moreover, the catalyst revealed very high stability upon continuous operation and remarkable tolerance to methanol.

Genetic models for the formation of uranium deposits almost invariably invoke the reduction of U(VI) to U(IV) as the deposition mechanism. However, the questions of when and how this reduction occurred are often not clear in most uranium deposits. For example, mineralization in the giant Olympic Dam Cu-U-Au-Ag deposit (Australia) occurs mainly in hematite-rich breccias of the oxidizing hematite-quartz-barite assemblage. Similarly, unconformity-related uranium deposits in the Athabasca Basin (Canada) are accompanied by extensive and intensive hematite- and quartz-rich alteration halos, pointing to a possible linkage between uranium mineralization and silicification. However, this linkage is not understood due to the lack of knowledge about the speciation and mechanism of uranium incorporation in microcrystalline and macrocrystalline silicas. In this contribution, microcrystalline silicas (agate and opal-CT) containing 27–137 ppm U have been investigated by microbeam synchrotron X-ray fluorescence mapping, microbeam synchrotron X-ray diffraction analysis, synchrotron X-ray absorption spectroscopy, Raman spectroscopy, Fourier transform infrared spectroscopy, and electron paramagnetic resonance spectroscopy. These data unravel the binding mechanism of uranyl silicate complexes in microcrystalline silicas and suggest a new mechanism of uranium deposition involving uranyl co-precipitation without the putative reduction process, providing a potential missing link between uranium mineralization and silicification for the formation of uranium deposits. In addition, new data on the uptake and long-term retention of elevated uranyl contents in microcrystalline silicas extend previous findings from their amorphous counterparts on these materials as an effective sink for uranium attenuation to higher temperatures, important to the storage and disposal of heat-generating nuclear waste in deep geological repositories.

This study investigated the biogeochemistry of uranium (U), and the co-occurring elements nickel (Ni) and arsenic (As), in colloids and sediments from two meromictic mine pit lakes that have considerably different depths and geochemistry. In order to characterize the processes controlling metal speciation and cycling in the pits, the distribution and speciation of the elements in colloidal size fractions were analyzed using micro- and ultrafiltration in combination with transmission electron microscopy. Sediment traps collected fresh sediments over the course of one year below the chemocline of the pit lakes and were subsequently analyzed by scanning electron microscopy (SEM) for morphology and chemical digestions. The most common particles found in the shallower pit consisted of Ca-O and Fe-O colloids, while the particles in the deeper pit were composed of Ca-S-O. Filtration results showed a higher abundance of metals in larger colloidal fractions in aged samples, suggesting that colloids can act as metal accumulators. Sediment traps showed the formation of Fe-O, Fe-S, Al-Si, and Ce-P phases, which were observed to sorb U and Ni. The overall U removal was calculated to be 0.9 g/m2/year in both pits, despite considerably different geochemical conditions between the two, and the maximum removal rates for As (shallow pit) and Ni (deeper pit) were 4.7 g/m2/year and 0.6 g/m2/year, respectively. Bottom sediments were also collected from both pits, and characterized using sequential extractions, SEM, synchrotron-based X-ray absorption spectroscopy and Laue diffraction techniques. These techniques showed that the stability of metals in the sediment follows the order Ni

A super-hydrophilic, polyvinylidene fluoride (PVDF) membrane was obtained through plasma-induced poly (acrylic acid) (PAA) polymerization followed by titanium dioxide nano particles (TiO2 NPs) self-assembly for oily produced water treatment. Fractional factorial design method was applied to investigate the effects of experimental factors and their interactions on membrane modification. The mechanism of TiO2 NPs self-assembly was explored through synchrotron-based X-ray analyses and comprehensive membrane characterization. It was found that nano-TiO2 was immobilized onto the membrane surface through PAA layer without valence change. For the first time, the mechanism of nano-TiO2 immobilization was confirmed to be the coordination of Ti4+ with carboxylic group. After modification, the TiO2 NPs were strongly and uniformly fixed on membrane surface, dramatically improving the hydrophilicity of the PVDF membrane surface. The permeation flux was increased more than four times, and the oil rejection rate was higher than 92%. The modified PVDF membrane has great potential in the application for various water-recovery systems, and this study provided a new insight into the nature of functionalized polymer membrane.

A novel membrane surface modification approach was proposed to successfully obtain a poly(vinylidene fluoride)-poly(acrylic acid)-ZnO (PVDF-PAA-ZnO) membrane with super-high water permeability and great oil rejection through cold plasma-induced PAA graft-polymerization followed by simple nano-ZnO self-assembly. The experimental parameters of modification were optimized and their optimal combination was identified using Taguchi orthogonal array (OA) design method. The PVDF-PAA-ZnO membrane was comprehensively characterized and the mechanism of nano-ZnO self-assembly was explored by contact angle measurement, scanning electron microscope (SEM) images, elemental analysis, tension test, Attenuated Total Reflection-Fourier Transform Infrared Spectroscopy (ATR-FTIR) and synchrotron-based X-ray analyses. It was revealed that ZnO nanoparticles were immobilized onto membrane surface through the adsorption of PAA layer to form a PAA-ZnO coating without valence change. The carboxyl groups of PAA layer provided complexing ligands to coordinate with Zn2+ and form bidentate species on the nano-ZnO surface. The firm PAA-ZnO coating on PVDF membrane surface converted its hydrophobic nature to hydrophilic, bringing about the dramatically improvement of membrane performance both in water permeation flux and oil rejection rate. The permeation flux of the PVDF-PAA-ZnO membrane was more than 10 times as great as that of the pristine PVDF membrane.

Technetium-99 (99Tc) is a major contaminant at nuclear power plants and several US Department of Energy sites. Its most common aqueous species, pertechnetate (TcO4-), is very mobile in the environment, and currently there are no effective technologies for its sequestration. In this work, a porous iron (pFe) material was investigated for TcO4- and perrhenate (ReO4-) sequestration from artificial groundwater. The pFe was significantly more effective than granular iron for both TcO4- and ReO4- sequestration under oxic conditions. The Tc removal capacity was 27.5 mg Tc/g pFe at pH ˜6.8, while the Re removal capacity was 23.9 mg Re/g pFe at pH ˜10.6. Tc K-edge XANES and EXAFS analyses indicated that the removed Tc species was 70-80% Tc(IV) that was likely incorporated into Fe corrosion products (i.e., Fe(OOH), Fe3O4) and 20-30% unreduced TcO4-. In contrast, the removed Re species was ReO4- only, without detectable Re(IV). In addition, the sequestered ReO4- was not extracted (

Understanding the association between precious metals and trace elements in ore minerals is integral to ore deposit research and exploration. In situ characterization of ore minerals is now at the forefront of this field. The power of in situ element mapping and characterization is the ability to combine geochemistry with mineralogical and broader geological context. Synchrotron radiation (SR) X-ray techniques such as X-ray Fluorescence (XRF) and X-ray Absorption Near Edge Spectroscopy (XANES) are incredibly powerful tools for studying ore systems with applications in exploration, geometallurgy, and remediation. We provide examples of these applications to gold-bearing samples from across the world-class Timmins gold camp in Canada. Analysis of thin sections, billet offcuts, as well as cut rock slabs highlights the versatility of SR-XRF and XANES analysis at multiple stages of deposit investigation and for multiple sample types. SR-XRF mapping of large areas at 20 μm resolution is very effective for quickly identifying and characterizing gold and trace element associations with gold, even in low grade and nuggety samples. Large area mapping is integral to quickly providing key geochemical information within the sample context as well as for improving efficiency and mitigating bias in grain selection for higher resolution analyses. High-resolution SR-XRF mapping and XANES analysis of individual mineral grains are compared to conventional EPMA mapping and reveals micrometer scale associations with trace metals, Au, and As. The characterization of trace element associations with different fluid events and gold mineralization styles is integral to understanding mineralizing systems and developing exploration vectors. Point XRF and XANES identified and characterized the presence and nature of refractory gold in pyrite as well as grain scale variability in As speciation. An early understanding of the distribution and redox state of gold, trace metals, and deleterious elements at the exploration stage has implications for mitigating future geometallurgy and remediation issues. The examples presented highlight the potential for the application of synchrotron studies early in the mine cycle for characterizing gold mineralization in orogenic systems.

Tantalum (Ta) exists in body-centered cubic (α phase), tetragonal (β phase), and face-centered cubic (fcc) crystal structures. The β phase is a metastable structure formed in thin films and is often mixed with the α phase. The fcc phase has only previously been reported as dispersed fine grains embedded in α or β phase. In this study, Ta thin films were deposited on silicon substrates by magnetron sputtering. A mixture of α and β phases was observed in the films when the deposition temperature was lower than 400 °C. The β phase content decreased gradually with the increase in deposition temperature, and completely disappeared at 400 °C. It is interesting that when the deposition temperature reached 500 °C, both α and β phases disappeared, and Ta films became a fcc structure. The structure and the stabilization of the fcc Ta thin films were further investigated using X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and X-ray absorption spectroscopy, and the results are presented in the present paper. This new finding would open new research and application directions for Ta materials.

CO2 reduction reaction (CO2RR) is one of the most promising approaches to alleviating greenhouse gas effect and simultaneously producing value-added chemicals and has been widely studied in recent years. To this end, a composite of indium species on CuO (InOx@CuO) was facilely synthesized for CO2RR, and it is found that the selectivity of the target product could be accurately tuned through incorporating post-transition species with Cu-based materials; the desirable Faraday efficiencies of over 90%, with a maximum value of 97.8%, toward CO formation were achieved in a wide potential window from −0.3 to −0.7 V. Moreover, a high CO partial current density of 7.2 mA cm−2 and a long-term stability of 50 h with negligible degradation were obtained over InOx@CuO. More importantly, CO starts to be observed at an ultralow potential of −0.196 V, further confirming the excellence of InOx@CuO for CO2RR toward CO formation. The results demonstrate that the achieved superiority derives from the essential In species on CuO, which not only introduces more active sites, but also better stabilizes the key intermediates, accelerates electron transfer and increases CO2 adsorption.

The fabrication of an efficient and low-cost photocathode still remains a big challenge. We herein report a Ag/CuxO@rGO/Mo photocathode for CO2 conversion. A unique wavelength-dependent performance is found to enhance the formation of the key intermediate groups by exciting photothermal local surface plasmonic resonance (LSPR) using the lights with wavelengths ranging from 550 to 600 nm. CO, H2 and CH4 can be stably produced with dual photoelectrodes using a neutral solution. An unbiased solar-to-gaseous-carbon-fuel efficiency (SGCF) of 0.51 % has been achieved, which sets a record for carbon gas fuel production with binary photoelectrodes. In addition, the CO/H2 ratio could be tuned in the range from 0.65 to 1.84, which makes it possible to fine tune the syngas production. The excellent PEC CO2 reduction capability achieved by the new wavelength-dependent catalytic route may shine some lights for the future design and development of the next-generation PEC materials and devices.

In this study, a two-stage type-2 fuzzy stochastic programming (TTSP) method is developed for supporting clean production of energy systems with carbon and pollutant mitigation under uncertainty. TTSP can handle multiple uncertainties expressed as type-2 fuzzy sets, random variables and interval values; it can also provide an effective linkage between the pre-regulated energy and environmental policies as well as the associated economic implication. The TTSP method is then applied to planning energy system of Shanghai through introducing carbon emission trading (CET) and green certificate (GC) schemes. The solutions obtained can help generate energy-supply and electricity-generation schemes under different carbon trading ratios and various development plans of renewable energy. Results reveal that (i) the city’s future energy structure would transit to the clean-production pattern on the basis of CET and GC policies; (ii) replacing fossil fuels with renewable energy sources (i.e. wind and photovoltaic power) can effectively facilitate reducing the emissions of pollutants (e.g., SO2, NOx and PM) and greenhouse gas (e.g., CO2). The results can help decision makers adjust energy and electricity supply, make appropriate mitigation plan, as well as gain insight into the relationship between mitigation schemes and optimal clean-production pattern.

Integrating organic upgrading and hydrogen electrolysis is recently regarded as a win-win strategy. However, it is still challenging to construct efficient robust electrocatalysts to considerably minimize their energy demand for such coupled reaction and simultaneously avoid the emission of environment-unfriendly CO2. Herein, the Cu2Se/Co3Se4 multivalent hetero-nanocrystals (CuCoSe-HNCs) are fabricated as efficient electrocatalysts through interfacial engineering, thus constructing abundant hetero-junctions on monodispersed CuCoSe-HNCs and facilitating the charge transfer at Cu–Se–Co hetero-interfaces. DFT studies reveal the multivalent CuCoSe-HNCs with hydroxylated surfaces, which possess complex species (Cu*−OOH, Co*−OOH, and SeOx) as synergistic active centers, thus effectively optimizing the surface adsorption/dissociation performance and suppress excessive oxidation to CO2. Hence, the methanol upgrading conversion to value-added formate is achieved at much low working potential (1.11V) with high faradaic efficiency (>98 %) and without CO2 emission, thus considerably decreasing the energy consumption for generating the only gas product of pure hydrogen.

In this work, single crystal VO2 (A) microbelts (MBs) were synthesized for the first time via the reduction of V2O5 thin films without a catalyst and without a hydrothermal process. The morphology and microstructure of the as-prepared VO2 (A) MRs was characterized by SEM, fluorescence mapping, Raman, XRD, XPS and FTIR. Results show that the as-prepared VO2 (A) MBs exhibit belt-like morphology with a rectangular cross section. The formation mechanism was proposed as melting of V2O5 thin film, VO2 nucleation in V2O5 droplets, VO2 growth. Light scattering measurements were carried out at varying sample temperatures. The results found that the as-prepared VO2 (A) MBs exhibit optical switching properties at a high temperature around 170 ℃, which is promising for designing thermally stable optical switching devices.

Fe-Al alloys with different Al contents have been exposed to a microwave plasma activated CH4-H2 gas mixture at 670 °C. An intermediate graphite layer formed on Fe-10Al substrate retarded diamond nucleation and deteriorated the interfacial adhesion, and severe metal dusting and carburization occurred. Diamond nucleation on Fe-20Al was enhanced by inhibited graphitization and cementite formation. Only Fe3AlCx-type precipitates were observed. On Fe-27Al and Fe-40Al alloys, graphitization and substrate carburization were completely prevented, producing enhanced nucleation and interfacial adhesion of diamond. The improved carburization resistance and diamond deposition with increasing Al contents is closely related to the formation of an alumina-rich layer on the alloy surface.

A rapid high throughput non-destructive method, using an X-ray microprobe beamline (Very Sensitive Elemental and Structural Probe Employing Radiation from Synchrotron, VESPERS, CLS Saskatoon), has been developed to screen multiple minerals in cereal and pulse meals. Starch spiked with commercial mineral standards cocktail at different concentrations was optimized to develop standard curve to determine mineral concentrations in grain meal samples. A grid sample holder to hold 84 samples was built for high precision and rapid analysis of multiple samples. The developed analytical method can be used for quantitative determination of eleven minerals including Ca, Cr, Mn, Fe, Ni, Co, Cu, Zn, Se, Rb and Mo at mg Kg− 1 or ppm concentrations. Method adaptability was assessed using a cereal crop wheat and pulse crop chickpea grain meal. The method was successfully used for Ca, Mn, Fe, Ni, Cu, Zn, Se, Rb and Mo determination in wheat and chickpea and measurements were cross analyzed using inductively coupled plasma mass spectroscopy ICP-MS technique for the same samples. The method is highly sensitive (sensitivity at ppm level) and can be adapted to analyze mineral concentrations in grain meal from crops of interest. The precise and reproducible high throughput screening method can be used in crop improvement to develop bio-fortified grains with increased mineral concentrations.

Electro-oxidative organic upgrading is recently considered as a promising strategy for energy saved H2 co-generation but still challenging for high productivity of value-added chemicals at large current density. Herein, the synthesized defects-rich Ni3S2-CNFs nanoheterostructures exhibit robust electrocatalytic performance for selectively catalyzing methanol to value-added formate with high productivity and without CO2 emission, in which the large current density (> 700 mA cm−2) is achieved with high faradaic efficiency (> 90%). By replacing the sluggish OER, the methanol upgrading reaction can greatly boost H2 co-generation from water with reduced energy consumption. DFT calculations indicate the in situ formed Ni–OOH and SOx species with synergistic effect can effectively modulate the d band center of Ni3S2 in Ni3S2-CNFs nanoheterostructures, acting as unique collaborative active sites for the thermodynamically favorable conversion from methanol to formate and suppressing the further oxidation to CO2, resulting in the high activity and selectivity of CO2-emission-free methanol upgrading reaction.

The intaking of water with undesired substances may cause many water-borne diseases. It is required to develop efficient and low-cost water purification technologies for developing countries. In this study, a new ceramic disk filter functionalized by chitosan/TiO2 nanocomposites (CT-CDF) for bacterial removal from drinking water was investigated. The characterization results showed that the chitosan/TiO2 nanocomposites were attached to the surface of CDFs. The optimal conditions for producing CT-CDFs were 0.2 g of chitosan, 0.05 g of TiO2, and 0.04 g of coating amount, respectively. The factorial analysis indicated that the illumination time and lamp power promoted the reduction of E. coli, but influent E. coli concentration showed a negative effect. There was an interaction between lamp power and influent E. coli concentration. The bacterial removal of CT-CDFs was due to the retention by irregular pores in CT-CDF, the cell membrane damage caused by the attached chitosan/TiO2 nanocomposites, and the oxidative stress in cells from ROS generated by nano-TiO2. Prolonging illumination time and increasing lamp power can promote the photocatalysis, resulting in the enhanced removal efficiency of CT-CDFs. The results of this study can provides not only an insight into the bacterial removal involving multiple mechanisms, but also an economic-feasible solution for resolving the water safety issues in developing countries.

VO2 microrods (MRs) have been successfully synthesized by the reduction of V2O5 thin films. The effects of reduction temperature and thickness of the precursor V2O5 thin films on the stochiometry and morphology of the resulting VO2 MRs have been studied in this work. Results show that size of the VO2 MRs increases with increasing precursor thickness due to the enlargement of the droplets during the melting of V2O5 thin films. Further, the growth of VO2 MRs from V2O5 droplets on a sapphire substrate form a unique angle between each other, which is probably due to epitaxial growth. Reduction temperatures between 600 °C and 650 °C are preferred for the growth of VO2 MRs, while temperatures lower or higher than this range produce V2O5 nanostructures or VO2 nanoparticles, respectively. HRTEM shows that during VO2 MR’s growth, the (110) plane remains parallel to the Si substrate, and a 10 nm amorphous interface was formed between the VO2 MR and the Si substrate. Optical properties of the MRs were examined by carrying out light scattering experiments as a function of temperature to identify the temperature range of insulator-to-metal (IM) and metal-to-insulator (MI) transition characteristics. The optical scattering experiments show the large influence of microrod (MR) size and distribution on the characteristics of MI and IM transitions. The transition behavior can range from polycrystalline film type transition to new unique features.

Ceramic water filter is suitable for low-income families and rural communities in developing countries to obtain safe drinking water because of its low cost and good performance. As an innovative effort, the ceramic disk filter coated with Ag/ZnO nanocomposites (AZ-CDF) was proposed in this study. The manufacture of AZ-CDFs was optimized by experiments based on the Box-Behnken design. The results of thermal field emission scanning electron microscopy (TFE-SEM) and very powerful elemental and structural probe employing radiation from a synchrotron (VESPERS) indicated that Ag/ZnO nanocomposites were mainly distributed on the upper surface of AZ-CDF. The antibacterial activity of AZ-CDF was investigated by detecting the variation of cell status and intracellular reactive oxygen species during a period of time using flow cytometry. Both non-photocatalytic and photocatalytic antibacterial activities of Ag/ZnO nanocomposite contributed to the bacterial reduction property of AZ-CDF. During filtration, the initial Escherichia coli (E. coli) concentration and illumination intensity also influenced the E. coli removal performance of AZ-CDF. When the light illumination intensity was 7000 Lux, AZ-CDF was appropriate to treat the water contaminated by E. coli concentration of less than 103 cfu/mL. Increasing illumination intensity resulted in the improvement of E. coli removal performance of AZ-CDF. It was concluded the main mechanisms for the E. coli removal of AZ-CDF were filtration, non-photocatalytic and photocatalytic antibacterial activities.

In this study, two Cu–W (Cu30–W, Cu40–W) and one Cu50–WC composites (all in wt.%) were synthesized by powder metallurgy and used as substrates for diamond coating in a microwave plasma enhanced chemical vapor deposition reactor. Optical microscopy, scanning electron microscopy, Raman spectroscopy, X-ray diffraction, indentation test and synchrotron-based high resolution X-ray near edge absorption spectroscopy were used to investigate the morphology, composition, microstructures and adhesion of diamond films. The results show that the adhesion of diamond coatings formed on these Cu–W alloy substrates is much higher than on pure Cu substrate. The adhesion improvement is primarily attributed to the reduced mismatch in the thermal expansion coefficients, and the formation of WC phase on the sub-surface of the substrate that strengthens the coating-substrate interfacial bonding.

In this study, an environmental friendly, reusable and low-cost functionalized flax fiber was fabricated to separate immiscible oil and water. Flax fibers were modified by plasma-induced poly(acrylic acid) (PAA) polymerization followed by nano-TiO2 self-assembly. A two-level fractional factorial design was engaged to analyze the modification influencing parameters and their interactions. The modified fiber was comprehensively characterized by synchrotron-based Fourier transform infrared spectroscopy (FTIR) and X-ray fluorescence (XRF). For the first time, the concentration distribution of functional groups and TiO2 nanoparticles (TiO2 NPs) were explored on flax fiber surface. The TiO2 NPs were found unevenly fixed on flax fiber surface with high concentration on abundant substrate. The hydrophilicity of nano-TiO2 self-assembled flax fiber was significantly improved, with water contact angle decreasing from 97.4° to 25.9° and almost doubled maximum oil holding pressure. The modified flax fiber showed stable performance of oil/water separation in alkaline and salty conditions and could be used for multiple cycles. The modified flax fiber could be further constructed into oil barrier with special wettability to separate oil.

When carbon steel is directly exposed in 99%H 2 –1%CH 4 gas mixture for plasma enhanced CVD deposition of diamond coatings, an intermediate graphite layer is preferentially formed on the substrate surface, and the substrate is subjected to a severe internal carburization attack. The diamond coatings formed easily delaminate from the steel substrate. Hot dip aluminizing treatment of the carbon steel has markedly promoted diamond nucleation, growth and interfacial adhesion. The formation of graphite intermediate phase on the substrate surface is effectively inhibited and the substrate carburization is also suppressed. The possible mechanism of this transition is discussed based on a series of analytical techniques.

Trace element analysis related to archaeological bone is viewed as one way to determine levels of element exposure in past populations. This area of research is complex because there is the potential for the incorporation of trace elements from the burial environment into archaeological bone. We tested the hypothesis that matching the spatial distribution of trace elements within cortical bone with the biological structures would provide evidence of biogenic uptake. We examined samples from a non-segregated Royal British Naval cemetery (1793–1822) in Antigua, West Indies. A key historical question related to this population was the extent of exposure to lead and the resulting health effects. Images from conventional light microscopy (histological) analysis of the bone samples were matched with elemental maps of calcium, strontium, and lead that were created through the use of synchrotron radiation X-ray fluorescence (SR-XRF). Biogenic uptake of both strontium and lead was indicated based on the localization of these trace elements within discreet microstructural elements. The successful integration of histological information with XRF data is a powerful technique for the interpretation of past biological events through trace elements.

Diamond coating on Ti-6Al-4V alloy was carried out using microwave plasma enhanced CVD with a super high CH4 concentration, and at a moderate deposition temperature close to 500 degrees C. The nucleation, growth, adhesion behaviors of the diamond coating and the interfacial structures were investigated using Raman, XRD, SEM/TEM, synchrotron radiation and indentation test. Nanocrystalline diamond coatings have been produced and the nucleation density, nucleation rate and adhesion strength of diamond coatings on Ti alloy substrate are significantly enhanced. An intermediate layer of TiC is formed between the diamond coating and the alloy substrate, while diamond coating debonding occurs both at the diamond-TiC interface and TiC-substrate interface. The simultaneous hydrogenation and carburization also cause complex micro-structural and microhardness changes on the alloy substrates. The low deposition temperature and extremely high methane concentration demonstrate beneficial to enhance coating adhesion strength and reduce substrate damage. (C) 2012 Elsevier B.V. All rights reserved.

Microwave plasma enhanced CVD deposition of adherent nanocrystalline diamond coating on pure Ti substrate was studied at a moderate temperature and with a wide range of CH4 concentrations. Under low CH4 concentrations, the adhesion failure of diamond coatings is primarily observed at the titanium carbide–substrate interface. Under higher CH4 concentrations, the diamond coating debonding occurs both at the diamond–carbide interface and carbide–substrate interface. On the whole, the nucleation density, nucleation rate and adhesion strength of diamond coatings grown on Ti substrate are enhanced with increasing CH4 concentrations. Synchrotron X-ray Laue micro-beam diffraction characterization of the underlying Ti substrate reveals that a microstructure coarsening occurs after hydrogen plasma etching, whereas the hydrogen penetration is effectively mitigated under super high CH4 concentrations.

The corrosion of two multiphase Fe–Ni–Al and Fe–Ni–Al–Cr alloys is studied at 650 °C in KCl-contaminated air. The oxidation rate of the alloys in air alone is low. When KCl is introduced, the corrosion is accelerated, producing a thick external scale of iron oxides, an intermediate layer of spinel, and a region of internal oxidation of Al. Potassium chromate is detected on Fe–Ni–Al–Cr surface that accounts for the degradation of protective chromia. An Al-depleted single phase region is observed in the front of the internal oxidation, due to the selective consumption of Al via an “active oxidation” process.

A radiation shielding study against primary and secondary gas bremsstrahlung is carried out for a tungsten collimator/stop, which is one of the components employed in the VESPERS beamline at the Canadian Light Source. The dose and dose rate are obtained by calculating the energy deposition in a water phantom which surrounds the collimator/stop unit. The dose rate behind a vacuum hole of the collimator/stop which leads to the experimental hutch is closely examined. The dose rates are further investigated with the addition of a tungsten shutter that is positioned in front of the collimator/stop.

Ionic photofragmentation of SO2 in the sulfur 2p and 2s regions has been investigated using monochromatic synchrotron radiation. Multi-stop time-of-flight mass spectrometry was used to collect photoelectron–photoion coincidence (PEPICO), photoion–photoion coincidence (PIPICO) and photoelectron–photoion–photoion coincidence (PEPIPICO) spectra simultaneously. Partial ion yields and partial ion-pair yields have been determined. Dissociation mechanisms of the productions of ion-pairs O+ S+ and O+ SO+ have been discussed briefly.

We report an extensive study on total and partial-ion-yield spectroscopy around the S 2p threshold in SO 2 . All positive and negative single-ion channels have been measured. Several cation fragments with the same mass/charge ratio could be distinguished by taking advantage of the 34 S isotope. The O − yield as a function of photon energy shows strong enhancement on the below-threshold resonances with two broad weak peaks above threshold corresponding to doubly excited resonances.

Absolute photoabsorption oscillator strengths (cross-sections) in the valence-shell discrete and continuum regions methyl propyl ether CH3OC3H7 have been measured from 5 to 32 eV using high-resolution (∼0.05 eV fwhm) dipole (e,e) spectroscopy. Wide-range spectra, spanning the UV, VUV and soft X-ray regions, have also been obtained at low-resolution (∼1 eV fwhm) from 5 to 200 eV for methyl propyl ether, and these wide-range spectra have been used to determine the absolute oscillator strength scales by employing valence-shell TRK (i.e., S(0)) sum-rule normalization. Evaluations of the S(−2) sum using the presently reported absolute differential photoabsorption oscillator strength data give a static dipole polarizability for methyl propyl ether in good agreement with previously reported polarizability values. Other dipole sums S(u), (u=−1,−3,−4,−5,−6,−8,−10), and logarithmic dipole sums L(u), (u=−1 to −6), are also determined from the presently reported absolute differential photoabsorption oscillator strength data using dipole sum-rules. The presently reported absolute photoabsorption oscillator strength data for methyl propyl ether (and all other atoms and molecules we have studied) are web-accessible at ftp.chem.ubc.ca/pub/cooper.

Absolute photoabsorption oscillator strengths (cross-sections) in the valence-shell discrete and continuum regions of diethyl ether C2H5OC2H5 have been measured from 5 to 32 eV using high-resolution (HR) (∼0.05 eV fwhm) dipole (e,e) spectroscopy. Wide-range spectra, spanning the UV, VUV and soft X-ray regions, have also been obtained at low-resolution (LR) (∼1 eV fwhm) from 5 to 360 eV which covers the valence-shell and C 1s inner-shell regions. The LR spectrum has been used to determine the absolute oscillator strength scale by employing valence-shell TRK (i.e., S(0)) sum-rule normalization. Evaluation of the S(−2) sum using the presently reported absolute differential photoabsorption oscillator strength data gives a static dipole polarizability for diethyl ether in good agreement with previously reported polarizability values obtained by other methods. Other dipole sums S(u), (u=−1,−3,−4,−5,−6,−8,−10), and logarithmic dipole sums L(u), (u=−1 to −6), are also determined from the presently reported absolute differential photoabsorption oscillator strength data using dipole sum-rules. The presently reported absolute photoabsorption oscillator strength data are web-accessible at ftp.chem.ubc.ca/pub/cooper.

Absolute photoabsorption oscillator strengths (cross-sections) in the valence-shell discrete and continuum regions of ethanol (C 2 H 5 OH) have been measured from 5 to 32 eV using high-resolution (∼0.05 eV fwhm) dipole (e,e) spectroscopy. A wide-range spectrum, spanning the UV, VUV and soft X-ray regions, from 5 to 200 eV has also been obtained at low-resolution (∼1 eV fwhm), and this has been used to determine the absolute oscillator strength scale by employing valence-shell TRK (i.e., S (0)) sum-rule normalization. The presently reported high- and low-resolution absolute photoabsorption oscillator strengths are compared with previously published data from direct photoabsorption measurements in those limited energy regions where such data are available. Evaluation of the S (−2) sum using the presently reported absolute differential photoabsorption oscillator strength data gives a static dipole polarizability for ethanol in excellent agreement (within 0.5%) with previously reported polarizability values. Other dipole sums S ( u ), ( u =−1,−3,−4,−5,−6,−8,−10), and logarithmic dipole sums L ( u ), ( u =−1 to -6), are also determined from the presently reported absolute differential photoabsorption oscillator strength data using dipole sum-rules.

The branching ratios for molecular and dissociative photoionization of benzene (C 6 H 6 ) have been measured in the VUV and soft X-ray regions using dipole (e,e+ion) coincidence spectroscopy (∼1 eV FWHM) at equivalent photon energies from the first ionization threshold up to 80 eV. The absolute partial oscillator strengths (cross-sections) for molecular and dissociative photoionization have been determined by combining previously reported absolute photoabsorption oscillator strength data [J. Electron Spectrosc. Relat. Phenom. 123 (2–3) (2002) 211–223] together with the photoionization branching ratios and the (multi-dissociative-corrected) photoionization efficiency obtained from time-of-flight mass spectra reported in the present work. The fact that the photoionization efficiency has been measured as greater than unity above ∼25 eV indicates the existence of multi-dissociative products from Coulomb explosion of multiply charged ions. Appearance potentials of all ion products from benzene are also reported. The presently reported results are compared with the previously published data where possible.

Absolute UV and VUV photoabsorption oscillator strengths (cross sections) for the valence shell discrete and continuum regions of benzene (C 6 H 6 ) have been measured from 4 to 56 eV using high resolution (∼0.05 eV fwhm) dipole (e,e) spectroscopy. A wide-range spectrum, spanning the UV, VUV and soft X-ray regions, from 5 to 200 eV has also been obtained at low resolution (∼1 eV fwhm), and this has been used to determine the absolute oscillator strength scale by employing valence shell TRK [i.e., S(0)] sum-rule normalization. The presently reported high and low resolution absolute photoabsorption oscillator strengths are compared with previously published data from direct photoabsorption measurements in those limited energy regions where such data are available. Evaluation of the S(−2) sum using the presently reported absolute differential photoabsorption oscillator strength data gives a static dipole polarizability for benzene in good agreement (within ∼3.4%) with published polarizability values obtained from optical measurements. Other dipole sums S( u ), ( u =−1, −3, −4, −5, −6, −8, −10), and logarithmic dipole sums L( u ), ( u =−1 to −6), are also determined from the presently reported absolute differential photoabsorption oscillator strength data using dipole sum-rules.

Absolute photoabsorption oscillator strengths for the valence shell of pyridine have been measured using dipole (e,e) spectroscopy at high resolution (∼0.05 eV FWHM) and low resolution (∼1 eV FWHM) from 4 to 30 eV and from 5 to 200 eV, respectively. The absolute photoabsorption oscillator strength scale (±5%) has been determined using valence shell TRK (i.e. S(0)) sum-rule normalization. The accuracy of the absolute scale has been verified using the S(−2) sum rule and literature values of the dipole polarizability. The low resolution photoabsorption results have been combined with time of flight mass spectral data measured using dipole (e,e+ion) coincidence spectroscopy (∼1 eV FWHM), to determine the absolute oscillator strengths for the molecular and dissociative photoionization of pyridine at equivalent photon energies from the first ionization threshold up to 60 eV.

The branching ratios for molecular and dissociative photoionization of dimethyl ether (CH 3 OCH 3 , DME) have been measured in the VUV and soft X-ray regions using dipole (e,e+ion) coincidence spectroscopy (∼1 eV FWHM) at equivalent photon energies from the first ionization threshold up to 80 eV. The absolute partial oscillator strengths (cross-sections) for molecular and dissociative photoionization have been determined from recently published absolute photoabsorption oscillator strength data [R. Feng, G. Cooper, C.E. Brion, Chem. Phys. 260 (2000) 391] together with the photoionization branching ratios and the (multi-dissociative-corrected) photoionization efficiency obtained from time-of-flight mass spectra reported in the present work. No stable multiply charged molecular ion(s) from DME have been found in the present work. However, the fact that the photoionization efficiency has been measured as greater than unity above ∼30 eV indicates the existence of multi-dissociative products from Coulomb explosion of multiply charged ions. Appearance potentials of all ion products from DME are also reported. The presently reported results are compared with the previously published data where possible.

Absolute UV and VUV photoabsorption oscillator strengths (cross-sections) for the valence shell discrete and continuum regions of dimethyl ether (CH3OCH3, DME) have been measured from 5 to 32 eV using high resolution (HR) (0.05 eV f.w.h.m.) dipole (e,e) spectroscopy. A wide-range spectrum, spanning the UV, VUV and soft X-ray regions, from 5 to 200 eV has also been obtained at low resolution (LR) (1 eV f.w.h.m.), and this has been used to determine the absolute oscillator strength scale by employing valence shell Thomas‐Reiche‐Kuhn (i.e., S(0)) sum-rule normalization. The presently reported HR and LR absolute photoabsorption oscillator strengths are compared with previously published data from direct photoabsorption measurements in those limited energy regions where such data are available. Evaluation of the SOˇ2U sum using the presently reported absolute diAerential photoabsorption oscillator strength data gives a static dipole polarizability for dimethyl ether in excellent agreement (within 0.5%) with previously reported polarizability values. Other dipole sums SOuU,Ouaˇ1;ˇ3;ˇ4;ˇ5;ˇ6;ˇ8;ˇ10U, and logarithmic dipole sums LOuU ,( uaˇ 1t oˇ6), are also determined from the presently reported absolute diAerential photoabsorption oscillator strength data using dipole sum rules. ” 2000 Elsevier Science B.V. All rights reserved.

The momentum distributions of the valence orbitals of sulphur dioxide have been studied by electron momentum spectroscopy (EMS), Hartree–Fock (HF) and density functional theory (DFT) calculations. The experiments were performed using an energy dispersive multichannel EMS spectrometer at an impact energy of 1200 eV plus the binding energy and in symmetric non-coplanar kinematics. The valence-shell binding energy spectra have been measured for all valence orbitals over the energy range 8–60 eV. Calculated synthetic binding energy spectra derived from many-body Green’s function and DFT calculations are compared with experiment. In the inner valence region, strong splitting of the 3b 2 and 5a 1 ionization is observed due to final state electron correlation effects. The measured momentum profiles of the valence orbitals are compared with HF calculations at the level of the target HF approximation, and with DFT calculations using B3LYP functionals at the level of the target Kohn–Sham approximation, with basis sets ranging from minimum (STO-3G) to large (AUG-cc-pV5Z(-h)). Generally, the shapes of the experimental momentum profiles are well reproduced by HF and DFT calculations using large diffuse basis sets. However, small discrepancies still exist between all theoretical treatments and experiment in the low momentum region for the (4b 2 +7a 1 +2b 1 ) and 6a 1 orbitals.

The branching ratios for molecular and dissociative photoionization of carbonyl sulfide (OCS) in the valence shell continuum regions and the inner shell (S 2p, 2s and C 1s) regions have been determined using dipole (e,e+ ion) coincidence spectroscopy (∼1 eV FWHM) at equivalent photon energies from the first ionization threshold up to 300 eV. The absolute partial oscillator strengths for molecular and dissociative photoionization have also been determined from recently published absolute photoabsorption oscillator strength data (R. Feng, G. Cooper, C.E. Brion, Chem. Phys. 252 (2000) 359) together with photoionization branching ratios and the (multi-dissociative-corrected) photoionization efficiency obtained from time-of-flight mass spectra reported in this work. The doubly charged molecular ion (OCS2+) and its dissociation products (mainly OC+, S+, O+ and C+) have also been studied in this work. Much higher relative abundances of these products have been found above the S 2p ionization edge (170.72 eV), which is due to Auger processes combined with Coulomb explosion. The presently reported results have been compared with previously published data where possible.