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The transformation of olivine during the conversion of CO2 to light hydrocarbons activated by mechanochemical treatments at different impact frequencies was studied by a combination of several complementary characterization methods including X-ray diffraction, Raman and 57Fe Mössbauer spectroscopy. Several olivine samples were studied as a function of the milling time, indicating the gradual transformation of FeII-containing olivine into new FeIII-containing weathering products including iron oxides, magnesium iron carbonates and silicates. The results presented here complement those of a previous study on the weathering process of olivine promoted by mechanochemical activation, by demonstrating the role of the redox activity of the iron species during the activation process. These additional spectroscopic results allow us to thoroughly understand the complex weathering mechanism and to correlate it with the efficiency of the CO2 conversion and storage properties of mechanochemically activated olivine. [ABSTRACT FROM AUTHOR]

Wet mechanochemical processing of olivine under a CO 2 atmosphere promotes the CO 2 sequestration in the form of MgCO 3 and the CO 2 reduction to CH 4 at room temperature. The effects of milling time and CO 2 pressure on the CO 2 storage and CO 2 reduction were evaluated at lab-scale. Wet mechanochemical introduces progressively significant morphological, structural, microstructural, and textural changes in olivine for prolonged milling times, inducing fast carbonation reaction after 15 min of ball milling. Long milling times stimulate the CO 2 conversion to CH 4 and decrease the carbonation reaction rate, because both reactions occurred simultaneously. The CO 2 sequestrated as MgCO 3 is about 4.83 wt% and 6.81 wt% for 1.0 atm of CO 2 after 120 min and 180 min of milling using different CO 2 charge strategy. The amount of CO 2 reduced to CH 4 was 24 and 33 mmoles/kg of olivine after 120 min with 1.0 and 1.5 atm of CO 2 , respectively. Wet milling of olivine in CO 2 atmosphere is a technique with potential for large-scale carbon mineralization. Unlabelled Image [ABSTRACT FROM AUTHOR]

The present work focused on the weathering reaction of olivine under CO 2 atmosphere to produce light hydrocarbons via mechanical process by using ball milling apparatus. The evolution of methane and light hydrocarbons with different amount of water is reported in detail, and the process efficiency compared with the thermally activated one. Methane and light hydrocarbons productions of at least three orders of magnitude larger, are detected for the mechanically activated process. Such significant improvement can be attributed to the extreme conditions experienced by the powders processed at each impact during ball milling, whit an estimated local temperature of 648 °C. Structural and microstructural characterization reveals the formation of serpentine and magnetite-based minerals, and the occurring of the carbonation process, which competes with serpentinization, confirming that carbon capture can take place during ball milling of olivine under low pressure of CO 2. High performing light hydrocarbons production from the weathering process of olivine mineral with carbon dioxide performed under mechanochemical processing exploiting ball milling apparatus. Image 1 • Weathering reaction of olivine under CO 2 to produce hydrocarbons is mechanically activated. • Molecular hydrogen is detected as a consequence of the weathering process. • CH 4 production is significantly higher in the mechanically activated process. • Local Temperature during single impact was estimated to corresponds to 648 °C. • Characterization proves the competition between serpentinization and carbonation processes. [ABSTRACT FROM AUTHOR]

The article offers information on the Student Audit and Research in Surgery (STARSurg), a national, student-driven research collaborative founded by group of medical students and surgical trainees in Great Britain. The research network allows students to join in high-quality studies, skill development to help them in research-active clinicians in the future. Members of the collaboration from other countries worldwide includes Ireland, Italy and Spain.

Due to the considerable interest in vanadium niobium oxides as a lithium storage material, the kinetics and transformation processes of the V2O5–5Nb2O5 system have been investigated by in situ synchrotron powder X-ray diffraction. The diffraction data after the thermal treatments selected with a view on the most significant features were supplemented with specific ex situ experiments conducted using a laboratory rotating anode X-ray diffractometer. The morphological changes of the mixed powders assuming an amorphous and nanocrystalline solid solution structure as a function of the temperature were inspected by scanning electron microscopy observations. The structural solution of the powder diffraction pattern of the phase recorded in situ at a temperature of about 700 °C was compatible with an orthorhombic crystal structure with the space group Amm2. The obtained lattice parameters for this structure were a = 3.965 Å; b = 17.395 Å, c = 17.742 Å, and the cell composition was V4Nb20O60, Pearson symbol oA84, and density = 4.10 g cm−3. In this structure, while the niobium atoms may be four-, five-, and six-fold coordinated by oxygen atoms, the vanadium atoms were six-fold or seven-fold coordinated. At the temperature of 800 °C and just above, the selected 1 : 2 and 1 : 3 V2O5–Nb2O5 compositions, respectively, returned mostly a tetragonal VNb9O25 phase, in line with earlier observations conducted for determination of the stability phase diagram of such quasi-binary systems. [ABSTRACT FROM AUTHOR]

Introduction: There has been a growing interest in addressing the surgical disease burden in low- and middle-income countries (LMICs). Assessing the current state of global surgery research activity is an important step in identifying gaps in knowledge and directing research efforts towards important unaddressed issues. The aim of this bibliometric analysis was to identify trends in the publication of global surgical research over the last 30 years. Methods: Scopus® was searched for global surgical publications (1987–2017). Results were hand-screened, and data were collected for included articles. Bibliometric data were extracted from Scopus® and Journal Citation Reports. Country-level economic and population data were obtained from the World Bank. Descriptive statistics were used to summarise data and identify significant trends. Results: A total of 1623 articles were identified. The volume of scientific production on global surgery increased from 14 publications in 1987 to 149 in 2017. Similarly, the number of articles published open access increased from four in 1987 to 68 in 2017. Observational studies accounted for 88.7% of the included studies. The three most common specialties were obstetrics and gynaecology 260 (16.0%), general surgery 256 (15.8%), and paediatric surgery 196 (12.1%). Over two times as many authors were affiliated to an LMIC institution than to a high-income country (HIC) institution (6628, 71.5% vs 2481, 28.5%, P < 0.001). A total of 965 studies (59.5%) were conducted entirely by LMIC authors, and 534 (32.9%) by collaborations between HICs and LMICs. Conclusion: The quantity of research in global surgery has substantially increased over the past 30 years. Authors from LMICs seemed the most proactive in addressing the global surgical disease burden. Increasing the funding for interventional studies, and therefore the quality of evidence in surgery, has the potential for greater impact for patients in LMICs. [ABSTRACT FROM AUTHOR]