Feasibility of (Pb, Ca)TiO3 thin films deposited on Pt/TiO2/SiO2/Si(100) for switching applications

[ES] Se han depositado láminas delgadas de (Pb,Ca)TiO3 sobre substratos de Pt/TiO2/SiO2/Si(100) por centrifugación, partiendo de soluciones sintetizadas por sol -gel. La concentración de las soluciones y el contenido de PbO se seleccionaron para minimizar las tensiones de las láminas cristalizadas y obtener la adecuada estequiometria. La cristalización mediante un calentamiento rápido (RTP), conduce a láminas con orientaciones preferentes [001]/[001], reducida capa interfacial ferroeléctrico-Pt y composición deseada. Los parámetros ferroeléctricos obtenidos muestran una mejora de las propiedades. Estas láminas presentan una fatiga y envejecimiento mucho más moderados que otros materiales alternativos depositados sobre substratos iguales, lo que permite considerar al método descrito como muy valioso para conseguir materiales susceptibles de emplear en aplicaciones de conmutación.[EN] (Pb,Ca)TiO3 ferroelectric thin films have been spin-coated on Pt/TiO2/SiO2/Si(100) substrates from sol-gel synthesized solutions. Selecting the solution concentrations and the excess of PbO content, stoichiometric composicion with reduced strains are obtained. Crystallization process by rapid thermal treatment (RTP) promote preferred orientations [001]/[100] resulting a thiner ferroelectric-platinum interface layer, which causes the improvement of fatigue and retain behaviour, despite the use of platinum electrodes. These experimental finds let to cosider the described methode of processing very convenient to prepare thin films of this composition to use on switching applications such as non volatil RAM memories.Peer reviewe

Conceptual design of the ITER fast-ion loss detector

et al.A conceptual design of a reciprocating fast-ion loss detector for ITER has been developed and is presented here. Fast-ion orbit simulations in a 3D magnetic equilibrium and up-to-date first wall have been carried out to revise the measurement requirements for the lost alpha monitor in ITER. In agreement with recent observations, the simulations presented here suggest that a pitch-angle resolution of ∼5° might be necessary to identify the loss mechanisms. Synthetic measurements including realistic lost alpha-particle as well as neutron and gamma fluxes predict scintillator signal-to-noise levels measurable with standard light acquisition systems with the detector aperture at ∼11 cm outside of the diagnostic first wall. At measurement position, heat load on detector head is comparable to that in present devices.This research was supported in part by the Spanish Ministry of Economy and Competitiveness (Grant Nos. RYC2011-09152, FIS2015-69362-P, and ENE2012- 31087) and the Marie Curie FP7 Integration Grant (No. PCIG11-GA2012-321455).Peer Reviewe

Effects of soil contamination by trace elements on white poplar progeny: seed germination and seedling vigour

11 páginas.-- 2 figuras.-- 2 tablas.-- 62 referencias.-- Electronic supplementary material in the online version of this article (doi:10.​1007/​s10661-015-4893-8) contains supplementary material, which is available to authorized users.Seed germination is considered a critical phase in plant development and relatively sensitive to heavy metals. White poplar (Populus alba) trees tend to accumulate Cd and Zn in their tissues. We tested if soil contamination can affect P. alba progeny, reduced seed germination and explored the distribution of mineral elements in the seed. For this purpose, fruits and seeds from female P. alba trees were selected from two contaminated and one non-contaminated areas. Seeds from all the sites were germinated using only water or a nutritive solution (in vitro). Concentrations of nutrients and trace elements in the fruits and seeds were analysed. Seedling growth in vitro was also analysed. Finally, a mapping of different elements within the poplar seed was obtained by particle-induced X-ray emission (PIXE). Germination was similar between different progenies, refuting our hypothesis that seeds from a contaminated origin would have reduced germination capacity compared to those from a non-contaminated site. Seedling growth was not affected by the contaminated origin. Cadmium and Zn concentrations in fruits produced by P. alba trees in the contaminated sites were higher than by those from the non-contaminated site. However, the nutritional status of the trees was adequate in both cases. Cd in seedlings was higher in those from contaminated soils although lower than in fruits, indicating a certain exclusion from seeds. Preliminary results of the PIXE technique showed that Al and Zn were distributed uniformly in the seeds (Cd was not detected with this technique), while the nutrients P and S were concentrated in the cotyledons.We thank JM Alegre for helping in the field work and Patricia Puente for helping in the lab work.We thank the National Accelerator Centre (CNA) of Seville for the analytical facilities. This study was supported by CGL2011-30285-C02 project, funded by the CICYT of the Spanish Ministerio de Ciencia e Innovación and European FEDER funds.Peer reviewe

Prevalencia y factores de riesgo de úlceras por presión

ObjetivoConocer la prevalencia de úlceras por presión (UPP) en pacientes incapacitados de una Zona Básica de Salud (ZBS) y caracterizar los factores de riesgo asociados a su aparición.DiseñoEstudio transversal observacional.EmplazamientoZBS Rincón de la Victoria (Málaga).ParticipantesPacientes incluidos en el Programa de Incapacitados (n = 178), de la ZBS, residentes en su domicilio o en una residencia geriátrica.MedicionesCuestionario específico con variables sociodemográficas y de salud. Para la valoración de factores de riesgo asociados con la formación de UPP, se utilizó la Escala de Norton Modificada (ENM). La variable resultado de interés fue la presencia o ausencia de UPP, localización y grado. El denominador para el cálculo de la prevalencia ha sido el total de pacientes valorados.ResultadosLa prevalencia fue del 12,9%. La característica sociodemográfica más significativa asociada con la presencia de úlceras en estos pacientes fue el nivel de instrucción del cuidador. Se constata asociación de determinadas variables del estado de salud del paciente con aparición de UPP.ConclusionesLos resultados alertan a la necesidad de la realización de protocolos diagnósticos y de intervención comunitaria para reducir la presentación de UPP en pacientes incapacitados que viven en la comunidad.ObjectivesTo study prevalence of pressure ulcers among functionally impaired patients in the community and evaluate risk factors associated with the development of pressure ulcers in these patients.DesignCross-sectional, observational study.SettingCommunity dwellers served by the Primary Health Care Area of Rincón de la Victoria in Málaga.ParticipantsAll patients included in the «Impaired Patient Programme» (n=178).MethodsA questionnaire was developed to ascertain demographic and health characteristics. Risk factors were evaluated with the Modified Norton Scale. The outcome variable of interest was presence or absence of pressure ulcers, their location and grade. The denominator used for the calculation of the prevalence was the total of evaluated patients.ResultsPrevalence of pressure ulcers in our Basic Health Area was 12.9%. The most important sociodemographic characteristic associated with the presence of pressure ulcers in these patients was the educational attainment of the caregiver. Health varaibles of the patient were also associated with the risk of developing ulcers.ConclusionsResults indicate the need of diagnostic protocols with standardised instruments and prevention plans to reduce pressure ulcers in the community. Longitudinal studies are needed to evaluate interventions in this area

Electro-Hydraulic Transient Regimes in Isolated Pumps Working as Turbines with Self-Excited Induction Generators

[EN] The use of pumps working as turbines (PATs) is a sustainable technical measure that contributes to the improvement of energy efficiency in water systems. However, its performance analysis in off-grid recovery systems is a complex task that must consider both hydraulic (PAT) and electrical machines (typically a self-excited induction generator-SEIG). Aside from several kinds of research that analyze the PAT-SEIG behavior under steady-state constant hydraulic and electrical conditions, this research focuses on the analysis of PAT-SEIG transient regimes, by analyzing their variation when a sudden change occurs in the hydraulic or electrical components. Analytical models were developed to represent the operation of SEIG, PAT, and the PAT-SEIG coupled system. Hydraulic and electromechanical experimental tests validated these models. An excellent fit was obtained when analytical and experimental values were compared. With these models, the impact on the operation of the PAT-SEIG system was examined when sudden change occurred in the excitation capacitances, resistive loads, or recovered head. With a sudden increase of resistive load, the hydraulic power and SEIG stator current remain almost constant. However, there is an increase of SEIG reactive power, decreasing the PAT-SEIG efficiency. Also, with a sudden increase of SEIG capacitors or PAT hydraulic head, the SEIG stator current increases once and not again, while PAT-SEIG efficiency decreases, but the induction generator can be overloaded. The development of this research is key to the advancement of future models which can analyze the coupling of micro-hydropower solutions.This research received some support from the project REDAWN (Reducing Energy Dependency in Atlantic Area Water Networks) EAPA_198/2016 from INTERREG ATLANTIC AREA.Madeira, FC.; Fernandes, JFP.; Pérez-Sánchez, M.; López Jiménez, PA.; Ramos, HM.; Costa Branco, PJ. (2020). Electro-Hydraulic Transient Regimes in Isolated Pumps Working as Turbines with Self-Excited Induction Generators. Energies. 13(17):1-23. https://doi.org/10.3390/en13174521S1231317Postacchini, M., Darvini, G., Finizio, F., Pelagalli, L., Soldini, L., & Di Giuseppe, E. (2020). Hydropower Generation Through Pump as Turbine: Experimental Study and Potential Application to Small-Scale WDN. Water, 12(4), 958. doi:10.3390/w12040958Capelo, B., Pérez-Sánchez, M., Fernandes, J. F. P., Ramos, H. M., López-Jiménez, P. A., & Branco, P. J. C. (2017). Electrical behaviour of the pump working as turbine in off grid operation. Applied Energy, 208, 302-311. doi:10.1016/j.apenergy.2017.10.039Fecarotta, O., Aricò, C., Carravetta, A., Martino, R., & Ramos, H. M. (2014). Hydropower Potential in Water Distribution Networks: Pressure Control by PATs. Water Resources Management, 29(3), 699-714. doi:10.1007/s11269-014-0836-3Ramos, H., & Borga, A. (1999). Pumps as turbines: an unconventional solution to energy production. Urban Water, 1(3), 261-263. doi:10.1016/s1462-0758(00)00016-9Fernandes, J. F. P., Pérez-Sánchez, M., da Silva, F. F., López-Jiménez, P. A., Ramos, H. M., & Branco, P. J. C. (2019). Optimal energy efficiency of isolated PAT systems by SEIG excitation tuning. Energy Conversion and Management, 183, 391-405. doi:10.1016/j.enconman.2019.01.016Yi, Y., Zhang, Z., Chen, D., Zhou, R., Patelli, E., & Tolo, S. (2017). State feedback predictive control for nonlinear hydro-turbine governing system. Journal of Vibration and Control, 107754631774001. doi:10.1177/1077546317740013Khan, M. F., & Khan, M. R. (2016). Analysis of voltage build-up and speed disturbance ride through capability of a self-excited induction generator for renewable energy application. International Journal of Power and Energy Conversion, 7(2), 157. doi:10.1504/ijpec.2016.076521Han, Y., & Tan, L. (2020). Dynamic mode decomposition and reconstruction of tip leakage vortex in a mixed flow pump as turbine at pump mode. Renewable Energy, 155, 725-734. doi:10.1016/j.renene.2020.03.142Pérez-Sánchez, M., Sánchez-Romero, F. J., López-Jiménez, P. A., & Ramos, H. M. (2018). PATs selection towards sustainability in irrigation networks: Simulated annealing as a water management tool. Renewable Energy, 116, 234-249. doi:10.1016/j.renene.2017.09.060Pérez-Sánchez, M., López-Jiménez, P., & Ramos, H. (2018). PATs Operating in Water Networks under Unsteady Flow Conditions: Control Valve Manoeuvre and Overspeed Effect. Water, 10(4), 529. doi:10.3390/w1004052

Characterization of scintillator screens under irradiation of low energy 133Cs ions

An imaging heavy ion beam probe (i-HIBP) diagnostic, for the simultaneous measurement of plasma density, magnetic field and electrostatic potential in the plasma edge, has been installed at ASDEX Upgrade. Unlike standard heavy ion beam probes, in the i-HIBP the probing (heavy) ions are collected by a scintillator detector, creating a light pattern or strike-line, which is then imaged by a camera. Therefore, a good characterization of the scintillator response is needed. Previous works focused on the scintillator behaviour against irradiation with light ions such as hydrogen and alpha particles. In this work we present the characterization of several scintillator screens - TG-Green (SrGa2S4:Eu2+), YAG-Ce (Y3Al5O12:Ce3+) and P11 (ZnS:Ag) - against irradiation with 133Cs+ ions, in an energy range between 5 and 70 keV and ion currents between 105 and 107 ions/(s·cm2). Three main properties of the scintillators have been studied: the ionolumenescence efficiency or yield, the linearity and the degradation as a function of the fluence. The highest yield was delivered by the TG-Green scintillator screen with > 8·103 photons/ion at 50 keV. All the samples showed a linear response with increasing incident ion flux. The degradation was quantified in terms of the fluence F1/2, which leads to a reduction of the emissivity by a factor of 2. TG-Green showed the lowest degradation with F1/2= 5.4·1014 ions/cm2. After the irradiation the samples were analyzed by Scanning Electron Microscopy (SEM), Rutherford Backscattering Spectrometry (RBS) and Particle Induced X-ray Emission (PIXE). No trace of Cs was found in the irradiated regions. These results indicate that, among the tested materials, TG-Green is the best candidate for the i-HIBP detector.This work received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No. 805162). G. Birkenmeier acknowledges funding from the Helmholtz Association under grant no. VHNG-1350. J. Galdon-Quiroga acknowledges funding from the Spanish Ministry of Science and Innovation under grant no. FJC2019-041092-I

Frozen ground and snow cover monitoring in Livingston and Deception islands, Antarctica: preliminary results of the 2015-2019 PERMASNOW project

Since 2006, our research team has been establishing in the islands of Livingston and Deception, (South Shetland archipelago, Antarctica) several monitoring stations of the active layer thickness within the international network Circumpolar Active Layer Monitoring (CALM), and the ground thermal regime for the Ground Terrestrial Network-Permafrost (GTN-P). Both networks were developed within the International Permafrost Association (IPA). In the GTN-P stations, in addition to the temperature of the air, soil, and terrain at different depths, the snow thickness is also monitored by snow poles. Since 2006, a delay in the disappearance of the snow layer has been observed, which could explain the variations we observed in the active layer thickness and permafrost temperatures. Therefore, in late 2015 our research group started the PERMASNOW project (2015-2019) to pay attention to the effect of snow cover on ground thermal This project had two different ways to study the snow cover. On the first hand, in early 2017 we deployed new instrumentation, including new time lapse cameras, snow poles with high number of sensors and a complete and complex set of instruments and sensors to configure a snow pack analyzer station providing 32 environmental and snow parameters. We used the data acquired along 2017 and 2018 years with the new instruments, together with the available from all our already existing sensors, to study in detail the snow cover. On the other hand, remote sensing data were used to try to map the snow cover, not only at our monitoring stations but the entire islands in order to map and study the snow cover distribution, as well as to start the way for future permafrost mapping in the entire islands. MODIS-derived surface temperatures and albedo products were used to detect the snow cover and to test the surface temperature. Since cloud presence limited the acquisition of valid observations of MODIS sensor, we also analyzed Terrasar X data to overcome this limitation. Remote sensing data validation required the acquirement of in situ ground-true data, consisting on data from our permanent instruments, as well as ad hoc measurements in the field (snow cover mapping, snow pits, albedo characterization, etc.). Although the project is finished, the data analysis is still ongoing. We present here the different research tasks we are developing as well as the most important results we already obtained about the snow cover. These results confirm how the snow cover duration has been changing in the last years, affecting the ground thermal behavior.info:eu-repo/semantics/publishedVersio

Gamma-ray sources imaging and test-beam results with MACACO III Compton camera

Hadron therapy is a radiotherapy modality which offers a precise energy deposition to the tumors and a dose reduction to healthy tissue as compared to conventional methods. However, methods for real-time monitoring are required to ensure that the radiation dose is deposited on the target. The IRIS group of IFIC-Valencia developed a Compton camera prototype for this purpose, intending to image the Prompt Gammas emitted by the tissue during irradiation. The system detectors are composed of Lanthanum (III) bromide scintillator crystals coupled to silicon photomultipliers. After an initial characterization in the laboratory, in order to assess the system capabilities for future experiments in proton therapy centers, different tests were carried out in two facilities: PARTREC (Groningen, The Netherlands) and the CNA cyclotron (Sevilla, Spain). Characterization studies performed at PARTREC indicated that the detectors linearity was improved with respect to the previous version and an energy resolution of 5.2 % FWHM at 511 keV was achieved. Moreover, the imaging capabilities of the system were evaluated with a line source of 68Ge and a point-like source of 241Am-9Be. Images at 4.439 MeV were obtained from irradiation of a graphite target with an 18 MeV proton beam at CNA, to perform a study of the system potential to detect shifts at different intensities. In this sense, the system was able to distinguish 1 mm variations in the target position at different beam current intensities for measurement times of 1800 and 600 s.</p

Gamma-ray sources imaging and test-beam results with MACACO III Compton camera

Hadron therapy is a radiotherapy modality which offers a precise energy deposition to the tumors and a dose reduction to healthy tissue as compared to conventional methods. However, methods for real-time monitoring are required to ensure that the radiation dose is deposited on the target. The IRIS group of IFIC-Valencia developed a Compton camera prototype for this purpose, intending to image the Prompt Gammas emitted by the tissue during irradiation. The system detectors are composed of Lanthanum (III) bromide scintillator crystals coupled to silicon photomultipliers. After an initial characterization in the laboratory, in order to assess the system capabilities for future experiments in proton therapy centers, different tests were carried out in two facilities: PARTREC (Groningen, The Netherlands) and the CNA cyclotron (Sevilla, Spain). Characterization studies performed at PARTREC indicated that the detectors linearity was improved with respect to the previous version and an energy resolution of 5.2 % FWHM at 511 keV was achieved. Moreover, the imaging capabilities of the system were evaluated with a line source of 68Ge and a point-like source of 241Am-9Be. Images at 4.439 MeV were obtained from irradiation of a graphite target with an 18 MeV proton beam at CNA, to perform a study of the system potential to detect shifts at different intensities. In this sense, the system was able to distinguish 1 mm variations in the target position at different beam current intensities for measurement times of 1800 and 600 s.</p