Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas
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Critical loads of nitrogen deposition and critical levels of atmospheric ammonia for semi-natural Mediterranean evergreen woodlands
No full textRecent studies have shown that seabirds are an important source of ammonia (NH3) emissions in remote coastal ecosystems. Nesting behaviour, which varies between seabird species, is likely to be a major factor in determining the proportion of excreted nitrogen (N) volatilised to the atmosphere as NH3. A long-term NH3 monitoring programme was implemented at a Scottish seabird colony with a range of species and associated nesting behaviours. The average monthly NH3 concentration was measured at 12 locations over a 14-month period, to infer spatial (i.e. species-specific) and temporal (seasonal) changes in NH3 emissions from different seabird species. An emissions model of seabird NH3, based on species-specific bioenergetics and behaviour, was applied to produce spatial estimates for input to a dispersion model.
Atmospheric NH3 concentrations demonstrated spatial variability as a result of differing local populations of breeding seabirds, with the highest concentrations measured above cliff nesting species such as Common guillemot Uria aalge, Razorbill Alca torda and Black-legged kittiwake Rissa tridactyla. NH3 concentrations above a colony of burrow nesting Atlantic puffin Fratercula arctica were low, considering the high number of birds. Emission of NH3 from excreted N exhibits a time lag of approximately a month. It is likely that all excreted N is lost from the colony by volatilisation as NH3 or surface run-off between breeding seasons. Modelled NH3 emissions and concentrations correlated with measured concentrations, but were much higher, reflecting uncertainties in the local turbulent characteristics. The results allow multi-species seabird population data to be used for the calculation of regional and global NH3 emission inventories, whilst improving understanding of N budgets of remote coastal ecosystems
SANDA Project D5.6: Report on correlation between integral experiments
No full textThe main purpose of SANDA project Task 5.2 is to assess the JEFF evaluated nuclear files using existing experiments, with the aim to contribute to the development of the future JEFF-4.0 nuclear data library. Adjustment and assimilation studies are powerful techniques to make the most of the information provided by experimental measurements and reducing biases in the calculation results and providing recommendations for nuclear data improvement. These techniques usually need to employ a large set of integral experiments to provide consistent information. However, the parameters of the experiments within this set can be correlated. Therefore, for the application of adjustment and assimilation techniques it is essential to have some prior knowledge of these correlations. For this reason, subtask 5.2.1, entitled ???Assessing correlations in integral experiments??? has been included within SANDA project Task 5.2. This report presents the results of this subtask. It includes a survey of the available correlations between integral experiments in the ICSBEB criticality experiment database, a review of the status of correlations between shielding benchmarks and some applications to particular cases, namely: (1) two cores of the EOLE facility investigated under the CAMELEON program; (2) a set of six cores loaded in the ZPR facility considered to be of interest for validation of nuclear data for Sodium Fast Reactors (SFRs); (3) reaction rates measured at the ASPIS Iron-88 benchmark experiment, and (4) an example of the application of Machine Learning techniques in the interpretation of uncertainties and correlations in a benchmark experiment
Chemical Texturization Processes for Non-conventional Silicon Substrates for Silicon Heterojunction Solar Cell Applications
No full textThe present work addresses the exhaustive study of the surfaces of multicrystalline silicon wafers after being subjected to a texturization process for silicon heterojunction solar cell applications. The investigations described include the effect that the time of isotropic etching based on combinations of hydrofluoric and nitric acids has on the reflectance, the morphology of the surfaces and the surface recombination through the evolution of the implicit open-circuit voltage. The influence of previous treatments and the elimination of porous silicon or silicon oxide formed on wafer surfaces as a consequence of these texturization processes are also addressed. Textured multicrystalline silicon wafer surfaces with a good uniformity and low weighted hemispherical reflectances (23???24%) have been achieved with short etching times. These texturization processes have also been tested on upgraded metallurgical silicon wafers, resulting in weighted hemispherical reflectance values around 23%, but at the cost of the appearance of important surface defects
A novel locus for autosomal dominant nonsyndromic hearing loss (DFNA44) maps to chromosome 3q28???29
No full textEn este art??culo se describe un nuevo locus asociado a hipoacusia abordando la localizaci??n del mismo desde la gen??tica cl??sica. La p??rdida auditiva neurosensorial no sindr??mica hereditaria (NSSHL) es un grupo de trastornos gen??ticamente muy heterog??neos. Las formas autos??micas dominantes representan hasta el 20 % de los casos. Hasta la fecha, se han identificado 39 loci mediante el an??lisis de ligamiento de familias afectadas que segregan formas de NSSHL en el modo autos??mico dominante (DFNA). La investigaci??n de una gran familia espa??ola NSSHL bilateral y progresiva de inicio postlingual con herencia autos??mica dominante excluy?? el ligamiento con los loci DFNA conocidos y, en un an??lisis de ligamiento a genoma completo posterior, el locus del trastorno se mape?? en la regi??n 3q28-29. Se obtuvo una puntuaci??n LOD m??xima de dos puntos de 4,36 en ??=0 para el marcador D3S1601. El an??lisis de haplotipos situ?? el nuevo locus, DFNA44, dentro de un intervalo gen??tico de 3 cM definido por los marcadores D3S1314 y D3S2418. El an??lisis de heterod??plex y la secuenciaci??n del ADN de las regiones codificantes y los l??mites de los exones/intrones de dos genes (CLDN16 y FGF12) en este intervalo no revelaron mutaciones causantes de la enfermedad
Surface characterisation of wafers for silicon-heterojunction solar cells
No full textSilicon-heterojunction solar cells have been gaining interest and market share in the last years. In a very short time, this technology has been able to reach 21% lab-scale efficiency [1] and 6% of the whole world photovoltaic production [2] by combining the good properties of crystalline or multicrystalline silicon with the advantages of thin-film silicon technology.
In contrast to the conventional cells based on thermal diffusion, silicon-heterojunction cells are basically surface- (or interface-) dominated. Junctions are not formed by doping part of a solid, but growing a thin film to a surface. This makes surface properties absolutely critical for the proper performance of the resulting device. The key role of surface treatments previous to thin-film deposition is widely reported in literature [3], [4]. Studies show that making a good silicon-heterojunction cell from a textured wafer is much more difficult than preparing it from a polished one. Finding the reasons for this difference and understanding the influence of the chemical composition and microstructure of the silicon surface on cell properties is the aim of the research described in the present paper.
The work has been focused on three kinds of ???1 0 0??? p-type monocrystalline-silicon wafers, respectively, float-zone polished, Czochralski rough (not polished, not textured), and Czochralski textured. Only one type of treatment has been covered: HF at different times, applied for different concentrations. Chemical composition has been analysed by AR-XPS (angle resolved X-ray photoelectron spectroscopy) measurements and possible microstructural changes have been monitored by SEM (scanning electron microscopy)
PSA Solar furnace: A facility for testing PV cells under concentrated solar radiation
No full texthttps://plu.mx/plum/a/?doi=10.1016%2Fj.solmat.2006.03.030&themeThe Plataforma Solar de Almer????a (PSA), the largest centre for research, development and testing of
concentration solar thermal technologies in Europe, has started to apply its knowledge, facilities and
resources to development of the Concentration PV technology in an EU-funded project HiConPV. A
facility for testing PV cells under solar radiation concentrated up to 2000 has recently been
completed. The advantages of this facility are that, since it is illuminated by solar radiation, it is
possible to obtain the appropriate cell spectral response directly, and the flash tests can be combined
with prolonged PV-cell irradiation on large surfaces (up to 150 cm2), so the thermal response of the PV cell can be evaluated simultaneously
Application of solar thermal desorption to remediation of mercury-contaminated soils
No full textSolar thermal desorption at temperatures up to 500 C is an innovative technology applied to the removal of mercury and arsenic from soil polluted by mining operations. As the soil is heated in a low and high-temperature solar system, the pollutant vapor pressure rises, producing mass transfer to the gas phase, which is then extracted by vacuum pumps and blower systems.
In the UPC low-temperature experiments, removal of mercury from the polluted soil was s much as 76%. The experimental results show that volatilization of mercury is only significant when the temperature is above approximately 130 C, which agrees with the predominant mercury solid phases detected. PSA middle-temperature experiments, showed that when soil and mine waste samples were
heated to 400???500 C, mercury elimination was significant (41.3???87%). However, the results from heating to 320 C or below 300 C, indicated little or negligible removal, possibly, because the fluid dynamics in the fluidized-bed module and the presence of cinnabar and pyrite rich-Hg as dominant mineral phases.
These results show the potential for efficiently removing mercury and other pollutants from solid matrices (soil, waste, etc.) at low temperatures
Proton irradiation effects on silicon heterojunction solar cells with MoOx selective contacts
No full textAbstract
In this study, we investigate the effects of proton irradiation on silicon-based heterojunction and molybdenum oxide (MoOx) selective contact solar cells. The main idea is to study their potential application in small satellites for measurement and monitoring. The irradiation dose simulates the aggressive environment found in Low Earth Orbit (LEO), where many satellites currently use Group III-VI (GaInP/GaAs/Ge) solar cells due to their superior efficiency, albeit at a higher cost. The experimental approach includes fabrication, irradiation, and characterization methods. Our results show a decrease in fill factor (F.F.) and overall efficiency after irradiation, mainly caused by a decrease in shunt resistance and an increase in series resistance. In addition, open-circuit voltage (Voc) and short-circuit current (Isc) may be affected by displacement damage defects caused by the irradiation process within the active region or by the formation of new point defects
A lumped parameter modelling of particle generation from Na-pool fires in SFR containments
No full textProgress in Nuclear Energy 109 (2018) 223???232Modelling of sodium-evaporation and formation of sodium-oxide aerosols from a sodium-pool fire is of fundamental
importance for the assessing of the radiological consequences in Sodium-cooled Fast Reactors severe
accidents. This paper summarizes the derivation of a simple model to estimate the amount and size of particles
being generated from Na-pool fires and its performance assessment, once implemented in an integral severe
accident tool (ASTEC-Na), against available large-scale separate effect tests. The model has been transposed in
analytical correlations which implementation in lumped-parameter severe accident codes is straightforward.
According to the comparisons to data set, the correlations do not adversely impact the code estimates with
respect to other more empirical alternative approaches and, in addition, the correlations remove any need of
user-defined ad-hoc parameters in the input deck concerning Na-based particles behaviour, as other alternates
do. Regarding code behaviour, the model predictions yield the same order of magnitude both in terms of suspended
aerosol concentration and diameter as data and capture the reliable measured data trends
Spanish research related to SMRs projects
No full textNuclear Engineering and Design 417 (2024) 112818Small modular reactors (SMRs) are advanced nuclear reactors with a power capacity of up to 300 MW(e) per unit. SMRs encompass a variety of reactor technologies
including light water reactors, high temperature gas reactors, molten salt reactors, liquid metal cooled fast reactors, and heat pipe technology-based reactors. The
research and design of these diverse SMR types require a broad set of technological capabilities related to nuclear engineering and safety. Within this context, this
article attempts to assess the current state of research and technological progress achieved by the Spanish research groups and companies. The results reveal a
significant level of maturity among these groups and companies in various domains such as neutronic analysis, thermal hydraulic analysis, the improvement of
models related to severe accident scenarios and an active involvement in the design of novel SMR