Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas

Repositorio Institucional del CIEMAT (Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas)
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    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

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    Fern??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

    Combination of Models to Generate the First PAR Maps for Spain

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    This work addresses the development of a PAR model in the entire territory of mainland Spain. Thus, a specific model is developed for each location of the study field. The new PAR model consists of a combination of the estimates of two previous models that had unequal performances in different climates. In fact, one of them showed better results with Mediterranean climate, whereas the other obtained better results under oceanic climate. Interestingly, the new PAR model showed similar performance when validated at seven stations in mainland Spain with Mediterranean or oceanic climate. Furthermore, all validation slopes ranged from 0.99 to 1.00; the intercepts were less than 3.70 umol m-2 s-1; the R2 were greater than 0.988, while MBE was closer to zero percent than -0.39%; and RMSE were less than 6.21%. The estimates of the PAR model introduced in this work were then used to develop PAR maps over mainland Spain that represent daily PAR averages of each month and a full year at all locations in the study field

    SOSTENIBILIDAD DEL PLAN ENERG??TICO ARGENTINO 2030 Resultados Preliminares

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    El presente trabajo busca estudiar la sostenibilidad del plan energ etico argentino hacia el a~no 2030 con m ultiples opciones. Para ello se desarrolla el concepto de sostenibilidad y sus componentes mas importantes. Al hablar de sostenibilidad se debe considerar el concepto a nivel mundial, con la cooperaci on colectiva de todas las Naciones. El no tomar acciones en los consumos energ eticos actuales podr a comprometer el bienestar de futuras generaciones alterando en forma notable el planeta tierra. Se aborda tambi en el concepto de modelos energ eticos y su importancia para poder guiar los planes energ eticos de una Naci on. En simultaneo se describe su estructura, analizando su conveniencia y exponiendo los aspectos de los modelos y el error que cometen

    Periodic DFT Study of the Thermodynamic Properties and Stability of Schoepite and Metaschoepite Mineral Phases

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    The thermodynamic properties of schoepite and metaschoepite were obtained by means of theoretical solid-state methods as a function of temperature. Since the values of these properties for schoepite have not been measured experimentally, they were predicted. The computed thermodynamic functions of metaschoepite were in excellent agreement with the experimental information. These functions were used to obtain the thermodynamic properties of formation of these materials from the corresponding elements. The calculated Gibbs free energy of formation of metaschoepite was shown to be very reliable and differ from the experimental value at 800 K by only 2.0%. Besides, it extends the range of temperature in which this property is known to 0???1000 K. Then, these properties were combined with those of other important uranyl-containing materials to study the reactions of formation of schoepite and metaschoepite from uranium trioxide and the reactions of transformation of these materials into dehydrated schoepite, rutherfordine, and soddyite. Schoepite becomes unstable with respect to uranium trioxide for temperatures higher than 110 ??C (383 ?? 27 K) and its dehydration occurs at 64 ??C (337 ?? 44 K). The corresponding values of these temperatures for metaschoepite are 82 ??C (355 ?? 6 K) and 5 ??C (278 ?? 9 K), respectively. Under hydrogen peroxide free conditions, schoepite and metaschoepite were found to be less stable than rutherfordine and soddyite. The thermodynamic stability of schoepite with respect to metastudtite and studtite was then studied under different conditions of temperature and concentrations of hydrogen peroxide. Schoepite and metaschoepite have very similar thermodynamic stabilities, the first being slightly more stable than the second one. The availability of the thermodynamic properties of these minerals allowed to determine their relative thermodynamic stability with respect to a rich subset of the most relevant secondary phases resulting from corrosion of spent nuclear fuel. Schoepite and metaschoepite were found to be the first and second most stable phases under intermediate hydrogen peroxide concentrations and the second and third most stable phases under high concentrations of hydrogen peroxide, respectively

    Analysis of alternative frequency control schemes for increasing renewable energy penetration in El Hierro Island power system

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    El Hierro, island declared as a biosphere reserve by the UNESCO in 2000, aims to become self-sufficient in energy and 100% free of greenhouse gas emissions. This isolated power system consists of diesel units and a hybrid Wind- Pump Storage Hydropower Plant (W-PSHP), equipped with Variable Speed Wind Turbines (VSWTs), Pelton turbines and a pump station with both fixed- and variable-speed pumps. During last years the annual average renewable energy participation is increasing, especially due to the improvements in the frequency control strategies in PSHP including the operation in short circuit mode. This performance involves an important reduction of the system efficiency but allows PSHP to regulate frequency deviations when available wind power is higher than power demand and the Diesel units are disabled. In this paper different alternative frequency control schemes are proposed so that Pelton units support to the frequency control can be substituted, avoiding energy losses owing to short-circuit operation. This way renewable energy participation would be increased. The control schemes are developed using pumping station regulation capacity, the proper kinetic energy of the VSWTs rotors and a new Flywheel Energy Storage System connected to the grid by means of power electronics. Nine different control cases have been presented, including hydraulic short circuit operating mode. Different simulations have been carried out and they confirm that proposed control schemes fulfil the initial research objectives and enable to improve the global energy efficiency of the system

    Targeted gene therapy into a safe harbor site in human hematopoietic progenitor cells

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    Directed gene therapy mediated by nucleases has become a new alternative to lead targeted integration of therapeutic genes in specific regions in the genome. In this work, we have compared the efficiency of two nuclease types, TALEN and meganucleases (MN), to introduce an EGFP reporter gene in a specific site in a safe harbor locus on chromosome 21 in an intergenic region, named here SH6. The efficiency of targeted integration mediated by SH6v5-MN and SH6-TALEN in HEK-293H cells was up to 16.3 and 15.0%. A stable expression was observed both in the pool of transfected cells and in established pseudoclones, with no detection of off-target integrations by Southern blot. In human hematopoietic stem and progenitor CD34+ cells, the nucleofection process preserved the viability and clonogenic capacity of nucleofected cells, reaching up to 3.1% of specific integration of the transgene in colony forming cells when the SH6-TALEN was used, although no expression of the transgene could be found in these cells. Our results show the possibility to specifically integrate genes at the SH6 locus in CD34+ progenitor cells, although further improvements in the efficacy of the procedure are required before this approach could be used for the gene editing of hematopoietic stem cells in patients with hematopoietic diseases

    Architectural Optimization of Dynamic Inception Modules in Convolutional Neural Networks using the Coral Reef Optimization Algorithm

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    The rapid advancement of Deep Learning (DL) has led to increasingly complex neu- ral network architectures in Artificial Intelligence (AI), often increasing computational requirements and environmental impact. This master???s thesis presents a novel methodology for optimizing the architecture of Inception modules within Convolutional Neural Networks (CNNs) that process data at multiple scales using the Coral Reef Optimization (CRO) algorithm, a bio-inspired evolutionary approach. Aligning with Green AI principles that emphasize efficiency and sustainability, we integrate a dynamic Inception module capable of adjusting branches, depths, and filter sizes with the CRO algorithm to effectively explore and exploit the architectural search space. To promote smaller, resource-efficient architectures, we introduce a custom evaluation metric that balances accuracy and model complexity by penalizing excessive parameters. Experimental results on the MNIST dataset demonstrate that the optimized models achieve competitive performance, reducing the number of parameters by up to 40% while maintaining accuracy comparable to standard models. This work contributes to the development of sustainable AI models and provides a foundation for future research in efficient neural architecture optimization

    Generation of dyskeratosis congenita-like hematopoietic stem cells through the stable inhibition of DKC1

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    Dyskeratosis congenita (DC) is a rare telomere biology disorder, which results in different clinical manifestations, including severe bone marrow failure. To date, the only curative treatment for the bone marrow failure in DC patients is allogeneic hematopoietic stem cell transplantation. However, due to the toxicity associated to this treatment, improved therapies are recommended for DC patients. Here, we aimed at generating DC-like human hematopoietic stem cells in which the efficacy of innovative therapies could be investigated. Because X-linked DC is the most frequent form of the disease and is associated with an impaired expression of DKC1, we have generated DC-like hematopoietic stem cells based on the stable knock-down of DKC1 in human CD34+ cells with lentiviral vectors encoding for DKC1 short hairpin RNAs. At a molecular level, DKC1-interfered CD34+ cells showed a decreased expression of TERC, as well as a diminished telomerase activity and increased DNA damage, cell senescence, and apoptosis. Moreover, DKC1-interfered human CD34+ cells showed defective clonogenic ability and were incapable of repopulating the hematopoiesis of immunodeficient NSG mice. The development of DC-like hematopoietic stem cells will facilitate the understanding of the molecular and cellular basis of this inherited bone marrow failure syndrome and will serve as a platform to evaluate the efficacy of new hematopoietic therapies for DC

    Radioactivity Levels and Heavy Metal Concentration in Mining Areas in Zacatecas, Mexico

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    The state of Zacatecas (Mexico) is one of the places most affected by pollution from the mining industry. A total of 21 samples from two areas were collected (6 samples from zone A and 15 samples from zone B) to evaluate the level of radioactivity and the degree of contamination with heavy metals. The activity concentration for 238U and 232Th was within typical values but that of 226Ra exceeded the value of 60 Bq kg???1 in both areas. In some places, the concentration of 40K was higher than the world average according to UNSCEAR. The radium equivalent activity Raeq and outdoor gamma exposure dose (D) indicated that some sites presented a radiological risk for the population. The excess lifetime cancer risk (ELCR) presented a higher risk than the world average in both sampled areas. Other parameters, such as the radiation index Ri, the external risk index Hex, and the internal risk index Hin, also indicated that there was a greater risk due to radiation exposure in these areas. In the case of heavy metals, some parameters, such as the EF, the Igeo, and the CF, showed that some places in zone A and zone B were contaminated with As and Pb. However, the concentration of selenium obtained by ICP-MS in the sampled soil was higher than the average in the Earth???s crust, both in mine waste dumps and in unaltered soil, which indicated that the background concentration for selenium in these places is higher than the world average

    Molecular cytogenetic characterization of rhabdomyosarcoma cell lines

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    Alveolar rhabdomyosarcomas (ARMS) are soft-tissue tumors that are genetically characterized by the presence of reciprocal translocations that generate the fusion gene PAX3-FOXO1A or PAX7-FOXO1A. For the study of the biologic consequences of such rearrangements, several cell lines have been generated. However, established cell lines accumulate chromosome and genetic aberrations that make it difficult to draw significant conclusions. We have applied a set of techniques that includes spectral karyotyping, fluorescence in situ hybridization (FISH), comparative genomic hybridization (CGH), and microarray CGH, to the most commonly used cell lines carrying the two fusion genes that are present in ARMS. We have identified the bacterial artificial chromosomes that cover the breakpoints at genes PAX3, PAX7, and FOXO1A, which can be used as FISH probes for the translocations. The RH30 cell line, positive for the PAX3-FOXO1A fusion gene, was found to be highly complex: wide range of chromosome number, more than 50 chromosome rearrangements, amplification of the hybrid gene, 24 DNA changes detected by conventional CGH, and 21 gene copy changes detected by microarray CGH (including several high-level amplifications). RMZ-RC2 cell line, positive for the PAX7-FOXO1A, was in the near-tetraploid range with only nonclonal structural rearrangements, amplification of the hybrid gene, 24 DNA changes by CGH, and 8 gene copy changes, confirming the previously reported high-level amplification of MYCN. (C) 2004 Elsevier Inc. All rights reserved

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    Repositorio Institucional del CIEMAT (Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas) is based in Spain
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