The global reach of single, calibrated ELF receivers operating in the Schumann resonance (SR) band (3-50 Hz) has been verified by global maps of energetic Q-burst locations and vertical charge moment change, and by locations of independently verified transient luminous events in a wide variety of locations worldwide. It has also been previously shown that with as few as six ELF receivers in widely separated locations, multi-station, multi-modal SR parameters extracted from the SR “background” signal can be inverted to provide the centroid locations of continental lightning “chimneys” (Asia, Africa, Americas) and their respective lightning activities in absolute units (coul2 km2/sec). This inversion method involves a propagation model for the Earth-ionosphere cavity with day-night asymmetry. The Earth is now populated with more than 30 calibrated ELF receivers making continuous time series observations. This circumstance is exploited in the present study to verify the findings of the ELF inversion method. During the period May 17-20 and 23-24, 2015, two independent sets of nine ELF receivers each, in widely-separated geographical locations (first set: Antarctica (3 sites), Hungary, Japan (2 sites), Poland, Spitzbergen, and USA; second set: Antarctica, Canada, Cape Verde Island, Lithuania, New Zealand, Saudi Arabia, Scotland, Tahiti, and USA), are used to compare the locations and source strengths of lightning chimneys. Detailed comparisons will be shown over Universal Time for selected days.
This work employs the double synchronous reference frame PLL (DSRF-PLL) as an effective method for grid synchronization of WT's power converters in the presence of transient faults in the grid. The DSRF-PLL exploits a dual synchronous reference frame voltage characterization, adding a decoupling network to a standard SRF-PLL in order to effectively separate the positive- and negative-sequence voltage components in a fast and accurate way. Experimental evaluation of the proposed grid synchronization method and simulations regarding its application to ride through transient faults verify and validate the excellent behavior of the DSRF-PLL in the grid synchronization of WT's power converters under unfavorable grid conditions
This work describes a methodology to optimize a grid-connected hybrid renewable energy system (HRES) that hybridizes photovoltaic, wind and forest biomass energy sources taking into account cost and environmental impact criteria from a life-cycle perspective. The developed model has been tested in a sample township in central Catalonia. The results show that life-cycle cost and life-cycle environmental impact are contradicting criteria. Low environmental impact layouts highly dependent on RES have higher costs than the ones more reliant on the electricity from the public grid, which present high environmental impact. A sensitivity analysis has been performed to analyze the trade-offs between different energy sources of the system, showing that wind power is the RE source with higher impact on the system since it presents lower cost and lower environmental impact, compared with biomass and photovoltaic power. Another important conclusion that can be drawn from such sensitivity analysis is that improving the rate of return on investment in HRES would be a very beneficial measure to encourage the use of renewable energies for electricity production, as it has significant positive outcomes in terms of both cost and environmental impact reduction.
Mehrdel, P.; Farré-Lladós, J.; Casals-Terré, J.; Karimi, S. International Symposium on Sensor Science p. 819 DOI: 10.3390/proceedings1080819 Data de presentació: 2018-09-27 Presentació treball a congrés
Hayran, Z.; Herrero, R.; Botey, M.; Kurt, H.; Staliunas, K. International Conference on Metamaterials, Photonic Crystals and Plasmonics p. 632-633 Data de presentació: 2018-07-25 Presentació treball a congrés
We propose a universal integral relation (a generalized Hilbert transform) relating the real and imaginary parts of the complex permittivity function of an object, which can provide invisibility with respect to particular range of directions, and for particular frequency ranges, i.e. on a specific demand. We demonstrate such invisibility by finite-difference-time-domain numerical calculations.
Suárez, S.; Calderon, L.; Gasso, S.; Roca, X. Resources, conservation and recycling Vol. 133, num. June, p. 120-131 DOI: 10.1016/j.resconrec.2017.11.023 Data de publicació: 2018-06-01 Article en revista
The production of virgin raw materials used in construction and the generation of construction and demolition waste (CDW) are key environmental issues in the construction industry. Portland cement and concrete are used extensively in the construction sector. Processing of CDW to produce recycled gypsum cement and recycled aggregates (RA) and their use in the production of structural and non-structural concrete are one way of slowing natural resource depletion and reducing the amount of CDW landfilled. This study proposes the application of multi-criteria decision analysis (MCDA) to compare the production of “green” concretes made from recycled gypsum cement (RGC) and RA with the production of conventional concrete made from natural aggregate and ordinary Portland cement. The VIKOR MCDA method was employed to determine the best or a set of good alternative(s) for concrete production, considering environmental and economic criteria. The life cycle assessment method was used to select the environmental evaluation criteria, and the reference cost of producing concrete alternatives in Spain was used to determine economic criteria. The results of this study, in which environmental and economic criteria were considered of equal weight, or one of the two criteria was given greater weight, showed that the best option for structural and non-structural concrete was the use of RGC and RA. In both cases, the worst alternative was conventional concrete. In conclusion, we found that the use of RGC and RA in concrete production is positive because it replaces the original raw material, reduces the environmental impact, and lowers the economic costs.
Giretti, A.; Vaccarini, M.; Casals, M.; Macarulla, M.; Fuertes, A.; Jones, R. Energy and buildings Vol. 167, p. 216-230 DOI: 10.1016/j.enbuild.2018.02.049 Data de publicació: 2018-05-15 Article en revista
Buildings subject to Energy Performance Contracts (EPCs) are usually quite complex public buildings, sometimes relatively old and usually barely documented from the technical standpoint. Gathering comprehensive and reliable technical information is a time consuming and expensive process that has to be carried out within the submission deadline. In these conditions, the standard approach to energy performance forecasting which uses detailed simulation is practically unfeasible.
This paper proposes a reduced-order modeling approach that is tailored to the EPC tendering phase. The proposed methodology extends a third order building model, introducing explicit, albeit still abstract, representations of the heating/cooling system, of the weather influence and of the end-user gains. The extended parameter set reflects to a large degree the information that is readily available in practical on-site surveying, or that can be easily calculated from that information. As a consequence of the simplified physics, a knowledge driven, practical calibration procedure, which provides an effective way of reducing uncertainty, is proposed. The calibration procedure analyses the uncertainty present in the available knowledge and uses the constraints imposed by the implemented physics on the parameters’ dynamic to assess their value estimation.
The modeling approach is exemplified through three case studies: the first one provides the comparison of the reduced-order model predictions with the outcomes of a detailed model of a small hospital, the second one is used to compare the reduced-order model predictions with the detailed measurements of energy consumption of a real building, and the third case study exemplifies the use in operational context with scarce information.
Runtime uncertainty such as unpredictable resource unavailability, changing environmental conditions and user needs, as well as system intrusions or faults represents one of the main current challenges of self-adaptive systems. Moreover, today’s systems are increasingly more complex, distributed, decentralized, etc. and therefore have to reason about and cope with more and more unpredictable events. Approaches to deal with such changing requirements in complex today’s systems are still missing. This work presents SACRE (Smart Adaptation through Contextual REquirements), our approach leveraging an adaptation feedback loop to detect self-adaptive systems’ contextual requirements affected by uncertainty and to integrate machine learning techniques to determine the best operationalization of context based on sensed data at runtime. SACRE is a step forward of our former approach ACon which focus had been on adapting the context in contextual requirements, as well as their basic implementation. SACRE primarily focuses on architectural decisions, addressing selfadaptive systems’ engineering challenges. Furthering the work on ACon, in this paper, we perform an evaluation of the entire approach in different uncertainty scenarios in real-time in the extremely demanding domain of smart vehicles. The real-time evaluation is conducted in a simulated environment in which the smart vehicle is implemented through software components. The evaluation results provide empirical evidence about the applicability of SACRE in real and complex software system domains.
Marangoni hydrodynamic motion and its potential technological application in reverse osmosis (RO) process for seawater desalination is discussed. The fundamental core idea in this note is the possibility to take advantage of the inherent concentration gradient in a RO process. It is well known that to run a RO process, it is necessary to apply a hydrodynamic pressure to overcome the osmotic pressure, however, by inducing a free-surface, e.g., a Leidenfrost surface, on the membrane wall, an additional hydrodynamic Marangoni stress could be generated, which, likewise than the osmotic pressure is driven by the concentration gradient but acting in the opposite direction, i.e., reducing the external hydraulic pressure to be applied. Utilizing a simplified geometrical and physical model, an analytical expression for the pressure reduction was derived. One important preliminary result in this work, is that the Marangoni stress can provide pressure against the osmotic pressure for membrane porous that are less than micrometric size.
Global airline alliances provide connectivity based on codesharing agreements between member airlines. An alliance member exit leads to the deletion of routes (if not operated by other members) which affects network connectivity. The paper measures the vulnerability of the codesharing network (CN) of Star Alliance, SkyTeam and oneworld, respectively, by applying the theory of complex networks. A normalized CN vulnerability metric is proposed. Using airline schedules data, a ranking of member airlines according to their share in the overall CN vulnerability is derived. The results for CNs are compared with the ones for the respective total network (TN) that includes routes with and without codesharing. The findings show that oneworld is the most vulnerable global airline alliance, SkyTeam ranks second followed by Star Alliance. The proposed graph theory approach might become a building block for a more comprehensive measurement of real world airline networks
Zambrano, M.; Tondi, E.; Mancini, L.; Lanzafame, G.; Trias, F. X.; Arzilli, F.; Materazzi, F.; Torrieri, S. Advances in water resources Vol. 115, p. 95-111 DOI: 10.1016/j.advwatres.2018.02.016 Data de publicació: 2018-05-01 Article en revista
In deformed porous carbonates, the architecture of the pore network may be modified by deformation or diagenetic processes altering the permeability with respect to the pristine rock. The effects of the pore texture and morphology on permeability in porous rocks have been widely investigated due to the importance during the evaluation of geofluid reservoirs. In this study, these effects are assessed by combining synchrotron X-ray computed microtomography (SR micro-CT) and computational fluid dynamics. The studied samples pertain to deformed porous carbonate grainstones highly affected by deformation bands (DBs) exposed in Northwestern Sicily and Abruzzo regions, Italy.
The high-resolution SR micro-CT images of the samples, acquired at the SYRMEP beamline of the Elettra - Sincrotrone Trieste laboratory (Italy), were used for simulating a pressure-driven flow by using the lattice-Boltzmann method (LBM). For the experiments, a multiple relaxation time (MRT) model with the D3Q19 scheme was used to avoid viscosity-dependent results of permeability. The permeability was calculated using Darcy's law once steady conditions were reached. After the simulations, the pore-network properties (effective porosity, specific surface area, and geometrical tortuosity) were calculated using 3D images of the velocity fields. These images were segmented considering a velocity threshold value higher than zero.
The study showed that DBs may generate significant heterogeneity and anisotropy of the permeability of the evaluated rock samples. Cataclasis and cementation process taking place within the DBs reduce the effective porosity and therefore the permeability. Contrary to this, pressure dissolution and faulting may generate connected channels which contribute to the permeability only parallel to the DB.
The main objective of this paper is to drive a rotary inverted pendulum by following a desired navigation instruction. This navigation is commanded by the user through a new electromagnetic device which is allowed to perturb the pendulum from its upright position. This apparatus consists of an electronic magnetic driving circuit to introduce commands and realized via two operated magnetic coils. So, the external programmed magnetic perturbation can be seen as external commandments. Therefore, the control problem statement is solved via a modified regulation control implementation, to maintain the pendulum on its upright position and giving free manipulation of the base of the rotary inverted pendulum. Hence, by using the corresponding H8-linear matrix inequality technique, a static state controller is designed and tested experimentally so supporting our findings.
Galvez, M.; Kock, J.; Tonks, A. Proceedings of the Royal Society of Edinburgh: Section A Mathematics Vol. 148, num. 2, p. 293-325 DOI: 10.1017/S0308210517000208 Data de publicació: 2018-04 Article en revista
By homotopy linear algebra we mean the study of linear functors between slices of the 8-category of 8-groupoids, subject to certain finiteness conditions. After some standard definitions and results, we assemble said slices into 8-categories to model the duality between vector spaces and profinite-dimensional vector spaces, and set up a global notion of homotopy cardinality à la Baez, Hoffnung and Walker compatible with this duality. We needed these results to support our work on incidence algebras and Möbius inversion over 8-groupoids; we hope that they can also be of independent interest.
When using distributed optical fiber sensors (DOFS) on reinforced concrete structures, a compromise must be achieved between the protection requirements and robustness of the sensor deployment and the accuracy of the measurements both in the uncracked and cracked stages and under loading, unloading and reloading processes. With this in mind the authors have carried out an experiment where polyimide-coated DOFS were installed on two concrete beams, both embedded in the rebar elements and also bonded to the concrete surface. The specimens were subjected to a three-point load test where after cracking, they are unloaded and reloaded again to assess the capability of the sensor when applied to a real loading scenarios in concrete structures. Rayleigh Optical Frequency Domain Reflectometry (OFDR) was used as the most suitable technique for crack detection in reinforced concrete elements. To verify the reliability and accuracy of the DOFS measurements, additional strain gauges were also installed at three locations along the rebar. The results show the feasibility of using a thin coated polyimide DOFS directly bonded on the reinforcing bar without the need of indention or mechanization. A proposal for a Spectral Shift Quality (SSQ) threshold is also obtained and proposed for future works when using polyimide-coated DOFS bonded to rebars with cyanoacrylate adhesive.
In this paper we study the spatial behavior of solutions to the equations obtained by taking formal Taylor approximations to the heat conduction dual-phase-lag and three-phase-lag theories, reflecting Saint-Venant's principle. In a recent paper, two families of cases for high order partial differential equations were studied. Here we investigate a third family of cases which corresponds to the fact that a certain condition on the time derivative must be satised. We also study the spatial behavior of a thermoelastic problem. We obtain a Phragmén-Lindelöf alternative for the solutions in both cases. The main tool to handle these problems is the use of an exponentially weighted Poincaré inequality.
Casadesus, M.; Macanás, J.; Colom, X.; Cañavate, J.; M.D. Alvarez; Garrido, N.; Molins, G.; Carrillo, F. Journal of composite materials DOI: 10.1177/0021998318766652 Data de publicació: 2018-03-30 Article en revista
The valorization of chicken feathers (CFs) waste was researched in this work through the preparation of composites using ground chicken feathers as a filler (20 % v/v) and polypropylene (PP) or low-density polyethylene (LDPE) matrices. In order to improve the compatibility between CFs and the matrixes two different strategies were followed. First, by the chemical modification of the CFs by either acetylation or silanization and, second, by the addition of adhesion promoters like maleated polypropylene (MAPP) and maleatead polyethylene (MAPE). The effect of those treatments on the physical, mechanical and structural properties of the thermoplastic-CFs biocomposites, which are mainly related to the fibre–matrix compatibility, was analyzed. Results show that the addition of 20 % (vol/vol) of unmodified CFs to the thermoplastic matrices results in a significant decrease of the tensile strength associated to a weak interfacial adhesion was assessed by SEM. However, when the adhesion promoters were added to the mixture, a significant increase in the tensile strength was noticed, particularly when the composites were obtained by a process at 180 °C. On the contrary, acetylation and silane treatments of the CFs did not result in any practical improvement of the macroscopic properties of the biocomposites
Las celdas solares de capa fina procesadas por métodos en solución surgieron como una interesante tecnología fotovoltaica para una producción roll-to-roll a bajo coste. El carácter de película delgada también asegura el bajo peso y la flexibilidad de los módulos solares, haciéndolos ideales para una gran variedad de aplicaciones donde los paneles de silicio no pueden ser usados. Además de las ventajas mencionadas, compartidas por todas las tecnologías de capa fina procesadas en solución, las celdas solares de polímero (PSCs) presentan propiedades únicas de semi-transparencia, lo que las hace útiles para aplicaciones en ventanas solares y muy competitivas como elementos integrados en edificios.En los últimos años, se ha logrado un progreso notable en el campo de las PSCs. La eficiencia de conversión de energía de las PSCs ha superado ya la barrera del 11%. Sin embargo, para poder competir finalmente con otras tecnologías de capa delgada procesadas en solución, la eficiencia del dispositivo debe mejorarse aún más. Debido a la baja movilidad de los portadores de carga para los típicos semiconductores orgánicos p-conjugados, el compromiso entre absorción óptica y recolección de carga limita el espesor de la mayoría de las capas fotoactivas que se utilizan actualmente a aproximadamente 100 nm. Para mejorar la limitada absorción de luz en dichas capas activas, el uso de estrategias ópticas adecuadas es muy relevante. Idealmente, se debería lograr un aumento de la absorción de la luz o de la corriente a cortocircuito sin afectar a los demás parámetros fotovoltaicos, tales como el voltaje a circuito abierto y el factor de llenado del dispositivo fotovoltaico.En esta tesis, incorporamos una nueva cavidad óptica planar unidimensional que presenta un carácter resonante en dos frecuencias no armónicas diferentes, y que llamamos two-resonance tapping cavity (TRTC). Con la TRTC demostramos que puede alcanzarse una captura óptima de la luz en celdas de capa fina sobre un amplio rango de longitudes de onda, mejorando en gran medida la fotocorriente sin sacrificar las propiedades eléctricas del dispositivo solar. La falta de estabilidad es otro obstáculo que puede prevenir la aplicación industrial de la tecnología de PSCs. De esta manera, en paralelo a un aumento de la eficiencia del dispositivo, se debe abordar el problema de su corta vida operativa. En esta tesis, llevamos a cabo varios experimentos para entender la física que determina el rápido deterioro de la nano-morfología de la capa activa en condiciones de iluminación. Además, proponemos e implementamos un nuevo procedimiento basado en la formación de una fase de PCBM altamente ordenada para eludir la vía de degradación y conseguir PSCs de alto rendimiento con una vida útil extendida. La tesis se ha dividido en cinco capítulos. El Capítulo 1 revisa brevemente algunas de las estrategias para la manipulación de fotones y las bases de los mecanismos de degradación en PSCs. El Capítulo 2 describe el concepto de TRTC y la implementación experimental de celdas de PTB7-Th: PC71BM incluyendo la TRTC. En el Capítulo 3 describimos el uso del concepto TRTC presentado en el Capítulo 2 para conseguir un balance óptimo entre voltaje a circuito abierto y fotocorriente en celdas flexibles de PBDBT: ITIC. En el Capítulo 4 demostramos una estrategia para mejorar la vida operativa de los PSCs basado en un tratamiento con luz UV para eliminar activamente el oxígeno quimisorbido en la capa de ZnO. Finalmente, en el Capítulo 5, se presenta un estudio en profundidad de la fast burn-in loss para las celdas de PTB7-Th:PC71BM, y se propone una nueva explicación de la ruta de degradación. Además, proponemos e implementamos una alternativa para evitar la degradación y conseguir celdas solares de alta eficiencia con una larga vida útil.
The study has obtained a classification of the synoptic patterns associated with a selection of extreme rain episodes registered in the Ebre Observatory between 1905 and 2003, showing a return period of not less than 10 years for any duration from 5 min to 24 h. These episodes had been previously classified in four rainfall intensity groups attending to their meteorological time scale. The synoptic patterns related to every group have been obtained applying a multivariable analysis to three atmospheric levels: sea-level pressure, temperature, and geopotential at 500 hPa. Usually, the synoptic patterns associated with intense rain in southern Catalonia are featured by low-pressure systems advecting warm and wet air from the Mediterranean Sea at the low levels of the troposphere. The configuration in the middle levels of the troposphere is dominated by negative anomalies of geopotential, indicating the presence of a low or a cold front, and temperature anomalies, promoting the destabilization of the atmosphere. These configurations promote the occurrence of severe convective events due to the difference of temperature between the low and medium levels of troposphere and the contribution of humidity in the lowest levels of the atmosphere.
Bogarra, S.; Corcoles, F.; Saura, J.; Moreno-Eguilaz, J.M.; Bakkar, M. International Conference on Renewable Energies and Power Quality p. 493-498 DOI: 10.24084/repqj16.362 Data de presentació: 2018-03-22 Presentació treball a congrés
In order to connect any power converters into the
grid there are some grid requirements to insure the safe operation of the grid. So, the control of the converters especially during abnormal condition e.g. during voltage sags is a very important key to guarantee the good behavior of the distributed generation
system. In this paper four control strategies,
will be stated in the literature, are discussed in order to ensure their ability to match the grid requirements when unsymmetrical voltage sags are produced in the network. The Spanish grid code did not give any information about the
negative sequence, and it only represents the positive sequence components. Therefore, the main contribution of this paper is to verify the grid code with not only the positive sequence but also with the negative sequence.
Moreover, the system is tested by simulation to show that the results cope well with the analytical equations.
García Carmona, Ó.; García Carmona, C.; Lis, M.; Cano, M.; Roldán, A.; Cruz, N. de la; Maestá, F.; Pallarès, M. Simposium de la Asociación Española de Químicos y Coloristas Textiles Data de presentació: 2018-03-21 Presentació treball a congrés
Fiedler, J.; García Carmona, Ó.; García Carmona, C.; Pallarès, M.; Lis, M.; Maestá, F.; Roldán, A.; Cruz, N. de la Simposium de la Asociación Española de Químicos y Coloristas Textiles Data de presentació: 2018-03-21 Presentació treball a congrés
Foams based on polyetherimide (PEI) with carbon nanotubes (CNT) and PEI with graphene nanoplatelets (GnP) combined with CNT were prepared by water vapor induced phase separation. Prior to foaming, variable amounts of only CNT(0.1–2.0wt%) or a combination of GnP(0.0–2.0 wt %) and CNT (0.0–2.0 wt %) for a total amount of CNT-GnP of 2.0 wt %, were dispersed in a solvent using high power sonication, added to the PEI solution, and intensively mixed. While the addition of increasingly higher amounts of only CNT led to foams with more heterogeneous cellular structures, the incorporation of GnP resulted in foams with ¿ner and more homogeneous cellular structures. GnP in combination with CNT effectively enhanced the thermal stability of foams by delaying thermal decomposition and mechanically-reinforced PEI. The addition of 1.0 wt % GnP in combination with 1.0 wt % CNT resulted in foams with extremely high electrical conductivity, which was related to the formation of an optimum conductive network by physical contact between GnP layers and CNT, enabling their use in electrostatic discharge (ESD) and electromagnetic interference (EMI) shielding applications. The experimental electrical conductivity values of foams containing only CNT ¿tted well to a percolative conduction model, with a percolation threshold of 0.06 vol % (0.1 wt %) CNT
En tecnología textil, el estudio de los fenómenos de fricción de fibras, hilos y tejidos tiene un gran interés puesto que permite conocer y predecir su comportamiento a lo largo del ciclo textil. El acabado silk-like es una práctica industrial que tiene por objeto conseguir que los tejidos de PES 100% presenten unes propiedades de cayente y mano similares a la seda natural. En este estudio se ha analizado la influencia de los parámetros del proceso de acabado silk-like sobre las propiedades friccionales de los tejidos de calada acabados mediante este método.
In textile technology, the study of the friction phenomena of fibres, yarns and fabrics is of great interest because it allows to know and to predict their behaviour throughout the textile cycle. Silk-like finishing, is used to obtain 100% PES fabrics mimicking natural silk in drape and hand. In this study, the influence of the parameters of the silk-like finishing process on the frictional properties of the polyester fabrics finished by this method have analyzed
García Carmona, C.; Pallarès, M.; Roldán, A.; Lis, M.; Cruz, N. de la; García Carmona, Ó.; Maestá, F.; Almudévar, E. Simposium de la Asociación Española de Químicos y Coloristas Textiles Data de presentació: 2018-03-21 Presentació treball a congrés
Drawing on the perceived work–family fit and balance perspective, this study investigates demands and resources as antecedents of work–life balance (WLB) across four countries (New Zealand, France, Italy and Spain), so as to provide empirical cross-national evidence. Using structural equation modelling analysis on a sample of 870 full time employees, we found that work demands, hours worked and family demands were negatively related to WLB, while job autonomy and supervisor support were positively related to WLB. We also found evidence that resources (job autonomy and supervisor support) moderated the relationships between demands and work–life balance, with high resources consistently buffering any detrimental influence of demands on WLB. Furthermore, our study identified additional predictors of WLB that were unique to some national contexts. For example, in France and Italy, overtime hours worked were negatively associated with WLB, while parental status was positively associated with WLB. Overall, the implications for theory and practice are discussed.
Four common waste keratin biofibers (human hair, dog hair, chicken feathers, and degreased wool) have been used as biosorbents for the removal of heavy metal ions from aqueous solutions. Different parameters of the biosorption processes were optimized in batch systems. For multiple-metal systems, consisting of a mixture of eight metal ions [Cr(III), Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), and Pb(II)], the total metal biosorption increased in the order: degreased wool¿>¿chicken feathers¿>¿human hair¿>¿dog hair. From the kinetic models tested, the pseudo-second-order model provided better results. Furthermore, biosorption isotherms of Pb(II) with the different keratin biofibers fitted the Langmuir model. Surface morphology of the biosorbents were analyzed before and after the sorption using Fourier transform infrared spectroscopy and scanning electron microscopy. The keratin biofibers tested are potentially good sorbents of metal ions, with degreased wool and chicken feathers being the more efficient ones
This book brings together a series of theory and practice essays on risk management and adaptation in urban contexts within a resilient and multidimensional perspective. The book proposes a transversal approach with regard to the role of spatial planning in promoting and fostering risk management as well as institutions’ challenges for governing risk, particularly in relation to new forms of multi-level governance that may include stakeholders and citizen engagement. The different contributions focus on approaches, policies, and practices able to contrast risks in urban systems generating social inclusion, equity and participation through bottom-up governance forms and co-evolution principles. Case studies focus on lessons learned, as well as the potential and means for their replication and upscaling, also through capacity building and knowledge transfer. Among many other topics, the book explores difficulties encountered in, and creative solutions found, community and local experiences and capacities, organizational processes and integrative institutional, technical approaches to risk issue in cities.
The present work is a part of the actions foreseen in the project " Upgrading of Opaque PET into innovative materials
(RevalPET)" financed by the FEDER funds through the INTERREG V A program. In this phase of the study, the effect
of TiO2 (2,4 % w/w) in the slow crack propagating behaviour of recycled PET from bottle. To this end, the Essential
Work of Fracture (EWF) technique has been applied on extrusion-calendered sheets from two types of recycled PET
from bottles: Transparent (rPET-T), of Spanish origin, and opaque (rPET-O) ) from France. According to the obtained
results, the existence of TiO2 in the formulation does not affect the essential parameter of the analysis (we) related to the
energy needed for the generation of new free surfaces, nor the propagation resistance of the same, related to the nonessential
Direct Steam Generation (DSG) is one of the most promising alternatives for parabolic trough solar plants to replace the synthetic oil and reduce the electricity cost. The focus of this work is to develop a comprehensive optical and thermo-hydraulic model for the performance prediction of DSG process under real operating conditions. Pressure drop and heat transfer characteristics are determined considering the effect of the non-uniform heat flux distribution due to the concentration of the sunlight. A numerical-geometrical method based on ray trace and finite volume method techniques is used to determine the solar flux distribution around the absorber tube with high accuracy. A heat transfer model based on energy balance is applied to predict the thermal performances of the different flow regimes in the DSG loop. The thermo-hydraulic behavior of the different DSG sections i.e. preheating, evaporation and superheating is investigated under different operating conditions. The validity of the model has been tested by being compared with experimental data from DISS test facility and other available models in the literature. The study also presents a comparative study of the effect of different parameters on the thermal gradient around the absorber tube. The analysis shows that the highest thermal gradient is occurring in the superheating section with a high risk of thermal bending and a potential damage risk. The model is also capable to evaluate the efficiency of a DSG loop for different conditions and help to take the appropriate control strategies to avoid flow instabilities in the DSG rows.
Ahmed, W. W.; Herrero, R.; Botey, M.; Hayran, Z.; Kurt, H.; Staliunas, K. Physical Review A Vol. 97, num. 3, p. 033824-1-033824-8 DOI: 10.1103/PhysRevA.97.033824 Data de publicació: 2018-03-15 Article en revista
We propose an approach based on a local Hilbert transform to design non-Hermitian potentials generating arbitrary vector fields of directionality, ¿p(¿r), with desired shapes and topologies. We derive a local Hilbert transform to systematically build such potentials by modifying background potentials (being either regular or random, extended or localized). We explore particular directionality fields, for instance in the form of a focus to create sinks for probe fields (which could help to increase absorption at the sink), or to generate vortices in the probe fields. Physically, the proposed directionality fields provide a flexible mechanism for dynamical shaping and precise control over probe fields leading to novel effects in wave dynamics.
Two different commercial hyperbranched poly(ethyleneimine)s (HBPEI), with molecular weights (MW) of 800 and 25,000 g/mol, and denoted as PEI800 and PEI25000, respectively, as well as the mixtures with a Diglycidyl Ether of Bisphenol-A (DGEBA) epoxy resin, have been studied using thermal analysis techniques (DSC, TGA), dielectric relaxation spectroscopy (DRS), and dynamic mechanical analysis (DMA). Only a single glass transition is observed in these mixtures by DSC. DRS of the HBPEIs shows three dipolar relaxations: ¿, ß, and a. The average activation energy for the ¿-relaxation is similar for all HBPEIs and is associated with the motion of the terminal groups. The ß-relaxation has the same average activation energy for both PEI800 and PEI25000; this relaxation is attributed to the mobility of the branches. The a-relaxation peak for all the HBPEIs is an asymmetric peak with a shoulder on the high temperature side. This shoulder suggests the existence of ionic charge trapped in the PEI. For the mixtures, the ¿- and ß-relaxations follow the behaviour of the epoxy resin alone, indicating that the epoxy resin dominates the molecular mobility. The a-relaxation by DRS is observed only as a shoulder, as a consequence of an overlap with conductivity effects, whereas by DMA, it is a clear peak.
Arjona, A.; Canal, J.M.; Garcia, J. International Journal of Environmental & Agriculture Research (IJOEAR) Vol. 4, num. 3, p. 14-27 DOI: 10.5281/zenodo.1213556 Data de publicació: 2018-03-09 Article en revista
Environmental care is an increasing concern in our society, and therefore integrated, circular economy allowing to close the industrial cycle is an urging demand. This project employs a residue of the food industry to recover the wastewaters from the textile industry, allowing closing the loop in two different industrial processes. Orange peel is a very abundant residue in the food industry. By chemical modification of the orange peel, we aim to produce a biosorbent to be employed in the treatment of the textile industry wastewater containing cationic dyes. In this project, we evaluate the capacity of the treated orange peels as cationic interchanger with different dissolutions of copper (II). Finally, their capacities as biosorbents were evaluated with four cationic dyes, examining the influence of different parameters like: biosorbent concentration, contact time, temperature and pH of the medium. An adsorption between 51 and 92 % was reached with the first treatment and also the possibility of the biosorbent recovery
Carrillo, F.; Casadesus, M.; Macanás, J.; Colom, X.; Cañavate, J.; M.D. Alvarez; Garrido, N.; Molins, G. AATCC International Conference p. 1-2 Data de presentació: 2018-03-07 Presentació treball a congrés
Lana, F.J.; M. Carmen Casas-Castillo; Serra, C.; Rodriguez, R.; Redaño, A.; Burgueño, A.; Martinez, M.D. Theoretical and applied climatology DOI: 10.1007/s00704-018-2434-4 Data de publicació: 2018-03-06 Article en revista
Heavy rainfall episodes are relatively common in the conurbation of Barcelona and neighbouring cities (NE Spain), usually due to storms generated by convective phenomena in summer and eastern and south-eastern advections in autumn. Prevention of local flood episodes and right design of urban drainage have to take into account the rainfall intensity spread instead of a simple evaluation of daily rainfall amounts. The database comes from 5-min rain amounts recorded by tipping buckets in the Barcelona urban network along the years 1994–2009. From these data, extreme 5-min rain amounts are selected applying the peaks-over-threshold method for thresholds derived from both 95% percentile and the mean excess plot. The return period curves are derived from their statistical distribution for every gauge, describing with detail expected extreme 5-min rain amounts across the urban network. These curves are compared with those derived from annual extreme time series. In this way, areas in Barcelona submitted to different levels of flood risk from the point of view of rainfall intensity are detected. Additionally, global time trends on extreme 5-min rain amounts are quantified for the whole network and found as not statistically significant.