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This paper discloses the research carried out at MCAT (INCAR-CSIC) in the last years, which has been aimed to develop a new microwave induced process (MIP) for the conversion of biosolids into syngas. The different organic substrates that can be processed, the operational conditions that lead to a maximum production of syngas and the characteristics of the syngas as well as the by-products obtained are discussed. Particular emphasis is placed on the partial recycling of the solid fraction and its role as microwave susceptor and as a catalyst of some of the gasification reactions taking place during the MIP of the organic residues. Additionally, some insights on the energy costs of the process are also given. Peer reviewed

The growth of self-ordered anodic aluminum oxide (AAO) templates with pore diameters in the 140-400 nm range is achieved by anodization in phosphoric acid at low temperatures (-4 °C). The procedure used in this study is able to completely avoid the >burning> of the oxide, highly frequent in anodizations in phosphoric acid solutions at high voltages. The current density measured during the anodizations is rather low, 0.6-0.7 mA/cm2; therefore, low growth rates have been also measured (<2 μm/h). AAO templates present a relatively low porosity value of 8.4%. However, a considerable pore-enlargement-rate (vΔd = 0.636 ± 0.101 nm/h) has been observed as a consequence of the chemical dissolution of the pore walls during the anodization. Thus, the results reported here constitute an exhaustive study on the preparation of large-diameter-pore self-ordered AAO templates that enables both to access to pore diameters up to now inaccessible and to efficiently overcome the difficulties of their fabrication process ascribed to its aggressive reaction conditions. © 2011 Elsevier Inc. All rights reserved. Authors want to thank the ERC 2008 Starting Grant number 240497 for financial support. Peer Reviewed

The global increase in energy demand and exponential exhaustion of fossil recourses has favored the development of new systems of electricity production. Photovoltaic solar energy is undoubtedly one that has the highest application in housings, due to its simplicity and easy implementation. In this work, a new prototype of photovoltaic solar tracker with Arduino platform was developed. Feedback control system that allows carrying out solar tracking with two axes using a stepper motor and linear actuator was established through an electronic circuit based on photodiodes. Moreover, real construction of the prototype was carried out, where the effectiveness of the design and its capacity to draw a maximum benefit of an incident radiation can be observed, placing the panel perpendicularly to the received energy and improving its performance for its application in future installations in housings. Results obtained from the comparison between the developed prototype and a static panel oriented according to the latitude of the area, show about 18% energy gain.

In this paper we provide a method to analytically compute the energy saving provided by the use of Transmission Power Control (TPC) at the MAC layer in Wireless Sensor Networks (WSN). We consider a classical TPC mechanism: data packets are transmitted with the minimum required power to achieve a given packet error probability, whereas the additional MAC control packets are transmitted with the nominal (maximum) power. This scheme has been chosen because it does not modify the network topology, since control packet transmission range does not change. This property also allow us to compute analytically the expected energy savings. Besides, this type of TPC can be implemented in the current sensor hardware, and can be applied directly to several MAC protocols already proposed for WSN. The foundation of our analysis is the evaluation of L ratio, defined as the total energy consumed by the network using the original MAC protocol divided by the total energy consumed if the TPC mechanism is employed. In the L computation we emphasize the basic properties of sensor networks. Namely, the savings are calculated for a network that is active a very long time, and where the number of sensors is supposed to be very large. The nodes position is assumed to be random -for the sake of example a normal bivariate distribution is assumed in the paper- and no node mobility is considered. In the analysis we stress the radio propagation and the distribution of the nodes in the network, that will ultimately determine the performance of the TPC. Under these conditions we compute the mean value of L. Finally, we have applied the method to evaluate the benefits of TPC for TDMA and CSMA with two representative protocols, L-MAC and S-MAC using their implementation reference parameters. The conclusion is that, while S-MAC does not achieve a significant improvement, LMAC may reach energy savings up to 10-20%.

Alkylated furan derivatives, such as 2,5-dimethylfuran (2,5-DMF) and 2-methylfuran (2-MF), have shown, at laboratory scale, a relatively high tendency to form soot. However, soot emissions from die...

[Abstract] This research work presents an artificial intelligence approach to predicting the hydrogen concentration in the producer gas from biomass gasification. An experimental gasification plant consisting of an air-blown downdraft fixed-bed gasifier fueled with exhausted olive pomace pellets and a producer gas conditioning unit was used to collect the whole dataset. During an extensive experimental campaign, the producer gas volumetric composition was measured and recorded with a portable syngas analyzer at a constant time step of 10 seconds. The resulting dataset comprises nearly 75 hours of plant operation in total. A hybrid intelligent model was developed with the aim of performing fault detection in measuring the hydrogen concentration in the producer gas and still provide reliable values in the event of malfunction. The best performing hybrid model comprises six local internal submodels that combine artificial neural networks and support vector machines for regression. The results are remarkably satisfactory, with a mean absolute prediction error of only 0.134% by volume. Accordingly, the developed model could be used as a virtual sensor to support or even avoid the need for a real sensor that is specific for measuring the hydrogen concentration in the producer gas. Junta de Andalucía; 1381442 Xunta de Galicia; ED431G 2019/01 Ministerio de Universidades; FPU19/00930

Throughout the 21st century, urban reports demand solutions to the obsolescence and aging process suffered by the existing buildings, due to the growth and expansion of cities that took place in the second half of the 20th century [...]

The 2008 financial crisis placed banks in the gaze of public opinion. Financial entities did not delay in reacting, intensifying their efforts in what had become known as sustainable banking, with the goal of counteracting the negative effects of their loss of reputation. Neither has the academic community delayed their reaction, with the rapid growth of scientific production around this topic. However, no review of this literature through qualitative methods or bibliometry exists. The work presented in this paper fills one of those gaps, setting up a statistical description of the principal features of sustainable banking research and carrying out an analysis about its knowledge structure via co-word analysis. The results show a rapid evolution of the topics addressed, highlighting studies about the consequences of banks’ sustainability programs on their competitiveness. Future trends point to the search for more complex models, the incorporation of new stakeholders in the analysis and the consideration of different contexts.