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Climate change and pathogen outbreaks are the two major causes of decline in Mediterranean holm oak trees (Quercus ilex L. subsp. ballota (Desf.) Samp.). Crown-level changes in response to these stressful conditions have been widely documented but the responses of the root systems remain unexplored. The effects of environmental stress over roots and its potential role during the declining process need to be evaluated. We aimed to study how key morphological and architectural root parameters and nonstructural carbohydrates of roots are affected along a holm oak health gradient (i.e. within healthy, susceptible and declining trees). Holm oaks with different health statuses had different soil resource-uptake strategies. While healthy and susceptible trees showed a conservative resource-uptake strategy independently of soil nutrient availability, declining trees optimized soil resource acquisition by increasing the phenotypic plasticity of their fine root system. This increase in fine root phenotypic plasticity in declining holm oaks represents an energy-consuming strategy promoted to cope with the stress and at the expense of foliage maintenance. Our study describes a potential feedback loop resulting from strong unprecedented belowground stress that ultimately may lead to poor adaptation and tree death in the Spanish dehesa. This research was mainly funded by the Spanish Government through the IBERYCA project (CGL2017-84723-P), its associated FPI scholarship BES- 2014-067971 (ME-V) and SMARTSOIL (PID2020- 113244GB-C21). It was further supported by the BC3 Marıa de Maeztu excellence accreditation (MDM-2017-0714; the Spanish Government) and by the BERC 2018–2021 and the UPV/EHUGV IT-1018-16 programme (Basque Government). Additionally, this research was further supported through the ‘Juan de la Cierva programme’ (MV; IJCI-2017-34640; the Spanish Government) and one project funded by the Romanian Ministry of Research, Innovation and Digitization through UEFISCDI (A-MH; REASONING, PN-III-P1-1.1-TE-2019-1099).

En este trabajo se ha monitorizado la torsión sufrida por una estructura de seguidores solares empleando sensores de fibra óptica. Estas medidas de campo se han obtenido con una red de sensores formada por 45 redes de difracción de Bragg en una huerta solar activa. Estos resultados, correlados con la velocidad y dirección del viento permitirían aumentar la eficiencia de los seguidores y ayudar a entender y prevenir efectos negativos relacionados con inestabilidades aeroelásticas. In this work, the torsion experienced by set of solar trackers is monitored using fiber optic sensors. The in-field measurements were obtained using a sensor network comprising 45 fiber Bragg gratings in an active solar plant. These results, correlated with wind speed and direction could increase efficiency and lead to understand and prevent harmful effects related to aeroelastic instability events. Este trabajo ha sido financiado por el proyecto WINDSOLAR (0011-1365-2017-000122) del Gobierno de Navarra, los proyectos TEC2016-76021-C2 y PID2019-107270RB-C22, los fondos FEDER, la European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 838143 y las fundaciones 'Caja Navarra' y 'la Caixa' con el proyecto LCF/PR/PR13/51080004.

Abstract The optical and photovoltaic properties of Si NCs/SiC multilayers (MLs) are investigated using a membrane-based solar cell structure. By removing the Si substrate in the active cell area, the MLs are studied without any bulk Si substrate contribution. The occurrence is confirmed by scanning electron microscopy and light-beam induced current mapping. Optical characterization combined with simulations allows us to determine the absorption within the ML absorber layer, isolated from the other cell stack layers. The results indicate that the absorption at wavelengths longer than 800 nm is only due to the SiC matrix. The measured short-circuit current is significantly lower than that theoretically obtained from absorption within the ML absorber, which is ascribed to losses that limit carrier extraction. The origin of these losses is discussed in terms of the material regions where recombination takes place. Our results indicate that carrier extraction is most efficient from the Si NCs themselves, whereas recombination is strongest in SiC and residual a-Si domains. Together with the observed onset of the external quantum efficiency at 700–800 nm, this fact is an evidence of quantum confinement in Si NCs embedded in SiC on device level.

The nZEB standards reduce the energy demand of these buildings to a minimum, obtaining this little energy from renewable resources. Taking these aspect into consideration, a thermoelectric cooler-heat pump is proposed to achieve the comfort temperature along the whole year. The same device can provide heat in winter and it can cool down the buildings in summer just by switching the voltage supply polarity. Heat pipes are studied to work on both sides of the thermoelectric modules in order to optimize the heat transfer as these devices present really good thermal resistances and they can work in any position. However, they present pretty different thermal resistances if they work on the cold or on the hot side of the modules. A methodology to thermally characterize these heat exchangers working in both orientations is proposed and a validated computational model is developed to optimize the thermoelectric cooler-heat pump for a nZEB application. The number of thermoelectric modules, the position of the device, the ambient temperature and the air mass flow determine the operation and consequently they need to be studied in order to optimize the application. The authors are indebted to the Spanish Ministry of Economy and Competitiveness for the economic support to this work, included in the DPI2014-53158-R research project.

The field of energy forecasting has attracted many researchers from different fields (e.g., meteorology, data sciences, mechanical or electrical engineering) over the last decade. Solar forecasting is a fast-growing subdomain of energy forecasting. Despite several previous attempts, the methods and measures used for verification of deterministic (also known as single-valued or point) solar forecasts are still far from being standardized, making forecast analysis and comparison difficult. To analyze and compare solar forecasts, the well-established Murphy–Winkler framework for distribution-oriented forecast verification is recommended as a standard practice. This framework examines aspects of forecast quality, such as reliability, resolution, association, or discrimination, and analyzes the joint distribution of forecasts and observations, which contains all time-independent information relevant to verification. To verify forecasts, one can use any graphical display or mathematical/statistical measure to provide insights and summarize the aspects of forecast quality. The majority of graphical methods and accuracy measures known to solar forecasters are specific methods under this general framework. Additionally, measuring the overall skillfulness of forecasters is also of general interest. The use of the root mean square error (RMSE) skill score based on the optimal convex combination of climatology and persistence methods is highly recommended. By standardizing the accuracy measure and reference forecasting method, the RMSE skill score allows—with appropriate caveats—comparison of forecasts made using different models, across different locations and time periods. Refereed/Peer-reviewed

In this project, we experimentally analyze the flow field through a Savonius rotor, which operates inside a wind-tunnel. For this we have made 3 sets of experiments: In the first one, we compare the information taken by a one directional probe, and the information taken by a two directional probe, so we give information about the way, or the different ways of measuring the speed of the wind. In the second one we compare the computation of the flow rate by mean of two meshes: one with 81 points of measuring, the other with 25 points of measuring, moreover we measure the speed of the wind ahead the rotor with different values of frequency for the fan and different values of rotational speed for the turbine. In the third one we analyze the flow field behind the Savonius rotor by means of an in-fase average technique. This project is useful for the researchers who are trying to find the best way of combining different kind of rotors, also for the researchers who are trying to improve the wind farms of vertical axis, therefore it is not an isolated project, it is into the development of alternative energy sources and, especially in the development in the field of domestic use. The present thesis begins describing the situation and the importance of the wind energy in the world and in Italy, and how important the rotor of vertical axis are, we will describe this kind of rotors and specifically the Savonius rotor. Secondly, we describe the tools and the instruments that we have used to carry out these experiments, and the scientific theory about the wind energy. Eventually, we describe the details of any experiment, and we show the information that we got, through all this information we will give conclusions. Industria Ingeniaritza Teknikoa Ingeniería Técnica Industrial

The transportation sector has traditionally been considered essential for commercial activities, although nowadays, it presents clear negative impacts on the environment and can reduce social welfare. Thus, advanced optimization techniques are required to design sustainable routes with low logistic costs. Moreover, these negative impacts may be significantly increased as a consequence of the lack of synergy between the sustainability objectives. Correspondingly, the concept of transport optimization in smart cities is becoming popular in both the real world and academia when public decision making is lit by operations research models. In this paper, however, we argue that the level of urban smartness depends on its sustainability and on the level of information and communication technologies developed in the city. Therefore, the operations research models seek to achieve a higher threshold in the sustainable transport standards in smart cities. Thus, we present a generic definition of smart city, which includes the triple bottom line of sustainability, with the purpose of analyzing its effects on city performance. Finally, this work provides a consolidate study about urban freight transport problems, which show that sustainability is only one facet of the diamond of characteristics that depict a real smart city. This work has been partially supported by the Spanish Ministry of Science, Innovation, and Universities (RED2018-102642-T; PID2019-111100RB-C22/AEI/10.13039/501100011033) and the SEPIE Erasmus+ Program (2019-I-ES01-KA103-062602). We also want to acknowledge the support received from the CAN Foundation in Navarre, Spain (Grant ID 903 100010434 under the agreement LCF/PR/PR15/51100007. We also want to thank the support of the Public University of Navarre doctoral program. Part of the work was funded under ePIcenter project (EU-H2020 grant 861584 and INGPHD-39-2020 from Universidad de La Sabana).