Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas
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Microbially Mediated Release of As from Mekong Delta Peat Sediments
Full text linkPeat layers within alluvial sediments are considered effective arsenic (As) sinks under reducing conditions due to the binding of As(III) to thiol groups in natural organic matter (NOM) and the formation of As-bearing sulfide phases. However, their possible role as sources of As for anoxic groundwaters remains unexplored. Here, we perform laboratory experiments to provide evidence for the role of a sediment peat layer in releasing As. Our results show that the peat layer, deposited about 8,000 years ago in a paleomangrove environment in the nascent Mekong Delta, could be a source of As to porewater under reducing conditions. X-ray absorption spectroscopy (XAS) analysis of the peat confirmed that As was bound to NOM thiol groups and incorporated into pyrite. Nitrate was detected in peat layer porewater, and flow-through and batch experiments evidenced the release of As from NOM and pyrite in the presence of nitrate. Based on poisoning experiments, we propose that the microbially mediated oxidation of arsenic-rich pyrite and organic matter coupled to nitrate reduction releases arsenic from this peat. Although peat layers have been proposed as As sinks in earlier studies, we show here their potential to release depositional- and/or diagenetically-accumulated As
Thermochemical assessment of Nicotiana glauca, Panicum virgatum and Elytrigia elongata as fuels for energy recovery through gasification
Full text linkProduction of energy from renewable biomass resources would reduce atmospheric CO2 increase associated with fossil fuels use. In this context, the objective of this study is to evaluate the energy potential of three herbaceous biomass crops (Nicotiana glauca, Panicum virgatum and Elytrigia elongata) grown on marginal lands. In order to do so, physicochemical and thermogravimetric characterization and gasification tests of each crop were performed. From the thermogravimetric analysis, it was estimated the activation energies of each energy crop using the Friedman method, obtaining values of 194.3, 224.9 and 220.6 kJ/mol for Nicotiana glauca, Elytrigia elongata and Panicum virgatum respectively. Then, in order to assess their potential as fuels for energy recovery, gasification tests were performed in a fluidized bed gasifier, using air and enriched air as gasifying agents. The ranges of experimental conditions used were the following: gasification temperature: 770-820??C; ER: 0.15-0.20; oxygen content: 21 and 27% respectively. The gasification gas obtained from these experiments had a calorific value between 3.5-5.0 MJ/Nm3, being always slightly higher for enriched air gasification. Besides, particle and tar contents were in the range of 4-17 g/Nm3 and 4-12 g/Nm3 respectively using air and 4-27 g/Nm3 and 4-18 g/Nm3 using enriched air. The results obtained showed that it is feasible to gasify the three selected crops grown on marginal lands with little differences in the gas produced offering an alternative to obtain a clean energy
Evolution of the THC conditions in the FEBEX in situ test after 18 years of experiment: Smectite crystallochemical modifications after interactions of the bentonite with a C-steel heater at 100 ??C
Full text linkFern??ndez, A.M., Kaufhold, S., S??nchez-Ledesma, D.M., Rey, J.J., Mel??n, A., Robredo, L.M., Fern??ndez, S., Labajo, M., Clavero, M.A., 2018. Evolution of the THC conditions in the FEBEX in situ test after 18 years of experiment: Smectite crystallochemical modifications after interactions of the bentonite with a C-steel heater at 100?????C.
Applied Geochemistry 98, pp. 152-171. https://doi.org/10.1016/j.apgeochem.2018.09.008. Supplementary data to this article can be found online at https://doi.org/10.1016/j.apgeochem.2018.09.008.Chemical and mineralogical investigations of the FEBEX repository demonstration experiment after 18 years confirmed those reactions which were identified in previous large scale tests: Fe-corrosion, Mg-accumulation, cation exchange, and mineral dissolution/precipitation. These reactions were mostly restricted to the bentonite-heater contact. However, other processes were detected. Fe oxidation of carbon-containing steel was dominated
by oxic corrosion and hydrolysis possibly through a similar Fischer-Tropsch synthesis reaction, leading to the monitored generation of H2, CO2 and both reduced (alkanes, alkenes) and oxidized non-volatile (carboxylic acids) hydrocarbons, which are in partial equilibrium with CO2/carbonate under oxidation states highly reduced. Therefore, temperature, water, oxygen (due to no gas-tight conditions), and other oxidizing agents regulated the redox state and activities of all species involved in the bentonite barrier, being sulfates reduced to H2S and pyrite, Fe-oxides (hematite/goethite) to magnetite and siderite, and Fe(III)-bearing smectite to saponite and chlorite. These mineral phases were detected as main corrosion products. The dissolved Fe2+ ions generated by reduction of Fe-oxides diffused away forming surrounding greenish halos in the bentonite. Because air was not excluded, most of the corrosion was oxic but locally reducing conditions were established.
Significant Mg accumulation was observed at the heater contact, which is related with the highest salinity values of the porewater (NaeMgeCaeCl water-type, 0.41M ionic strength), the presence of saponite (trioctahedral Mg-smectite), brucite and Fe-rich chlorite; and a modification in the dehydroxylation temperature of the dioctahedral smectite clay mineral particles, together with the precipitation of carbonates and an increase in Ca/
Mg at interlayer sites, Na being depleted.
The mechanism for the structural clay mineral alteration seems to be Fe(III) structural reduction, rather than the C-steel heater/liner corrosion. Because Fe2+ cations are more stable in trans octahedral sites, rearrangements in crystal lattice seem to have formed cis-trans interstratifications favouring the migration of Mg to octahedral sites and the segregation of Mg2+ trioctahedral domains. Thus, both a solid-state transformation, producing
high-charge/low charge layers similar to vermiculite ones; as well as dissolution-precipitation transformation, with the crystallization of a trioctahedral Mg-smectite (saponite), brucite and chlorite in localized zones of the bentonite barrier, seem to be inferred, depending probably on f(O2), temperature, the amount of structural Fe(II) and Mg concentration in the pore water.
The observed clay mineral transformations induced changes in some of the physico-chemical properties of the bentonite, decreasing the total cation exchange capacity and BET surface area. However, these modifications were restricted to the bentonite at close contact with the heater. The rest of bentonite from the FEBEX in situ test maintained its performance as an engineered barrier
MLL gene fusions in human leukaemias: in vivo modelling to recapitulate these primary tumourigenic events
Full text linkRecurrent reciprocal chromosomal translocations are frequently found in leukaemias and sarcomas as initiating events in these cancers. Mouse models of chromosomal translocations are not only important for the elucidation of the mechanism of these factors underlying the disease but are also important pre-clinical models for assessing new drug combinations, developing new rational therapeutic strategies based on new drugs and testing novel macromolecular drugs. We describe three technologies for creating chromosomal translocation mimics in mice, applied specifically to understand how the MLL-fusions contribute to leukaemia. An important finding of this work is that the lineage of the tumours can be controlled by the MLL-protein fusion. The translocation mimic methods can be applied to any human reciprocal chromosomal translocation
Adopta Ciencia: La Tecnolog??a responde a los retos de la sociedad
Full text linkEn esta tercera edici??n de ADOPTA CIENCIA hemos querido centrar la tem??tica en c??mo la ciencia y la tecnolog??a van de la mano, tal y como muestra nuestro cartel, en busca de solucionar algunos de los retos de nuestra sociedad. La ciencia proporciona el conocimiento y las bases te??ricas para el desarrollo de la tecnolog??a, y la tecnolog??a es la que permite impulsar nuevos descubrimientos y avances cient??ficos que antes no eran posibles. Por tanto, son dos conceptos que se complementan y que adem??s tambi??n se unen a la demanda que continuamente se solicita desde la sociedad. Todo ello permite lograr avances y mejoras en todos los ??mbitos de nuestra vida, generando a la vez nuevos retos, con lo que el conocimiento sigue avanzando como una espiral infinita. As??, tecnolog??a, ciencia y sociedad constituyen una terna de elementos perfectamente enlazados entre s?? y en continua comunicaci??n, dando lugar a lo que hemos venido a denominar IMPULSO SOCIAL, lema que en esta edici??n hemos considerado para la actividad.ADOPTA CIENCIA es una iniciativa con la que los investigadores del CIEMAT queremos dar a conocer, tanto internamente en nuestro centro de investigaci??n como externamente, las actividades en las que se trabaja y c??mo estas dan soluci??n a los retos que plantea continuamente nuestra sociedad. Soluciones a unos retos que buscan ayudarnos a conseguir una sociedad m??s avanzada, moderna, justa y sostenible. Se busca dar a conocer al entorno social que nos rodea la importancia y la repercusi??n que tiene nuestro trabajo de investigaci??n, lo que para nosotros podr??a ser la definici??n de divulgar. Y esta divulgaci??n es una labor que debe recaer en los propios investigadores, como parte de su trabajo, como una responsabilidad y no una mera actividad relegada a los espacios de tiempo menos ocupados. El CIEMAT ya ha demostrado su compromiso con la divulgaci??n cient??fica y son muchas las iniciativas relacionadas con este concepto.Esta publicaci??n presenta cinco art??culos en los que los investigadores del CIEMAT desarrollan algunas ideas sobre el trabajo que est??n realizando en sus grupos de investigaci??n, as?? como cu??les son las aplicaciones de los mismos a los retos de la sociedad. El art??culo que presenta Jorge describe la utilizaci??n de los accionamientos el??ctricos en la generaci??n y almacenamiento de energ??a y en la movilidad. Por su parte, el art??culo desarrollado por Silvia nos introduce las t??cnicas de caracterizaci??n de materiales met??licos irradiados y nos ense??a a interpretar los resultados obtenidos. ??scar nos presenta un art??culo en el que describe las principales aplicaciones en que se pueden utilizar los aceleradores de part??culas. El art??culo que ha preparado Marta nos muestra las principales aplicaciones m??dicas de las radiaciones ionizantes. Y finalmente, Jes??s nos describe en su art??culo la compatibilidad de materiales estructurales con el almacenamiento y transporte de hidr??geno
Geographical Information System-based methodologies for energy planning: Optimizing site selection for renewable energy plants
No full textGeographic Information Systems (GIS) have become pivotal in the renewable energy sector, enabling comprehensive
planning and management through advanced spatial analysis and visualization capabilities. This study examines recent
advancements in GIS methodologies applied to the optimal sitting of onshore renewable energy plants, identifying their
strengths, limitations, and key areas for improvement. Focus is placed on the methodologies employed, the criteria and
constraints used to delineate incompatible areas, and the selection and weighting of evaluation factors for site suitability.
The findings emphasize the critical role of incompatible zones in the planning process and advocate for further exploration
of this component. The study highlights the necessity of constructing diverse scenarios to account for the multifaceted
nature of renewable energy planning, demonstrating how GIS-based models, while powerful, should be regarded as
preliminary tools rather than definitive solutions. Additionally, it underscores the importance of developing a robust
theoretical framework to guide the effective integration of GIS in land-use planning, ensuring enhanced decision-making and
sustainable energy infrastructure development. This research provides valuable insights to improve future planning efforts in
the transition to renewable energy
Fusion research in a Deuterium-Tritium tokamak
No full textThis is a perspectives article, based on a presentation made at the 50th EPS Conference on Contr. Fusion and Plasma Phys, 8-12 July 2024, in Salamanca, Spain. The EPS poster received the People???s Choice Award, selected by the conference participants.The recent ITER re-baselining calls for new fusion-relevant research best carried out in a DT-capable tokamak device with similar technical choices. The present paper describes key issues that could be addressed in a Suitably Enhanced DT-capable Tokamak (SET), with tungsten plasma facing components, boronization systems, and 10 MW of ECRH, based on JET???s characteristics and knowledgebase. We discuss hardware options, and show that fusion-relevant operational scenarios could be achieved. Notably, development, validation and testing of fusion and nuclear diagnostics, to be used in next generation devices, would require a DT-capable tokamak as described
First experimental observation of zonal flows in the optimized stellarator Wendelstein 7-X
No full textIn this work, we present the first experimental evidence of the presence of zonal flow (ZF) structures in the optimized stellarator Wendelstein 7-X. Using an assortment of diagnostics, flux surface-uniform, electrostatic flow oscillations have been measured, showing a radial scale in the range of tens of ion gyroradii. As well, indications are found of local turbulence being modulated by the ZF. Measurements show remarkable agreement with the ZF predicted by nonlinear gyrokinetic simulations. These results represent the first direct measurement of ZF in a large stellarator suitable for the validation of models in reactor-relevant conditions