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
Cyclic oligo(butylene 2,5-furandicarboxylate) and e-caprolactone were copolymerized in bulk at 130-150 °C by enzymatic ring opening polymerization using CALB as catalyst. Copolyesters within a wide range of compositions were thus synthesized with weight-average molecular weights between 20,000 and 50,000, the highest values being obtained for equimolar or nearly equimolar contents in the two components. The copolyesters consisted of a blocky distribution of the e-oxycaproate (CL) and butylene furanoate (BF) units that could be further randomized by heating treatment. The thermal stability of these copolyesters was comparable to those of the parent homopolyesters (PBF and PCL), and they all showed crystallinity in more or less degree depending on composition. Their melting and glass-transition temperatures were ranging between those of PBF and PCL with values increasing almost linearly with the content in BF units. The ability of these copolyesters for crystallizing from the melt was evaluated by comparative isothermal crystallization and found to be favored by the presence of flexible e-oxycaproate blocks. These copolyesters are essentially insensitive to hydrolysis in neutral aqueous medium but they became noticeably degraded by lipases in an extend that increased with the content in CL units.
Mehrdel, P.; Farré-Lladós, J.; Casals-Terré, J.; Karimi, S. International Symposium on Sensor Science p. 819 DOI: 10.3390/proceedings1080819 Fecha de presentación: 2018-09-27 Presentación de trabajo en congreso
Ruiz, M.; Mujica, L.E.; Alferez, E.; Acho, L.; Tutivén, C.; Vidal, Y.; Rodellar, J.; Pozo, F. Mechanical systems and signal processing Vol. 107, p. 149-167 DOI: 10.1016/j.ymssp.2017.12.035 Fecha de publicación: 2018-07 Artículo de revista
The future of the wind energy industry passes through the use of larger and more flexible wind turbines in remote locations, which are increasingly offshore to benefit stronger and more uniform wind conditions. The cost of operation and maintenance of offshore wind turbines is approximately 15-35% of the total cost. Of this, 80% goes towards unplanned maintenance issues due to different faults in the wind turbine components. Thus, an auspicious way to contribute to the increasing demands and challenges is by applying low-cost advanced fault detection schemes. This work proposes a new method for detection and classification of wind turbine actuators and sensors faults in variable- speed wind turbines. For this purpose, time domain signals acquired from the operating wind turbine are represented as two-dimensional matrices to obtain grayscale digital images. Then, the image pattern recognition is processed getting texture features under a multichannel representation. In this work, four types of texture characteristics are used: statistical, wavelet, granulometric and Gabor features. Next, the most significant ones are selected using the conditional mutual criterion. Finally, the faults are detected and distinguished between them (classified) using an automatic classification tool. In particular, a 10-fold cross-validation is used to obtain a more generalized model and evaluates the classification performance. Coupled non-linear aero-hydro-servo-elastic simulations of a 5MW offshore type wind turbine are carried out in several fault scenarios. The results show a promising methodology able to detect and classify the most common wind turbine faults.
Herrera Lameli, Ch.; Gamboa, C.; Custodio, E.; Jordan, T.; Godfrey, L.; Jódar, J. Science of the total environment Vol. 624, p. 114-132 DOI: 10.1016/j.scitotenv.2017.12.134 Fecha de publicación: 2018-05-15 Artículo de revista
The Cordillera de la Costa is located along the coastline of northern Chile, in the hyperarid Atacama Desert area. Chemical and isotopic analyses of several small coastal springs and groundwater reservoirs between 22.5 °S and 25.5 °S allow understanding groundwater origin, renewal time and the probable timing of recharge. The aquifers are mostly in old volcanic rocks and alluvial deposits. All spring waters are brackish, of the sodium chloride type due to intensive concentration of precipitation due aridity and for deep groundwater to additional water-rock interaction in slowly renewed groundwater and mixing with deep seated brines. The heavy d18O and d2H values in spring water are explained by recharge by the arrival of moist air masses from the Pacific Ocean and the originally lighter values in the deep wells can be associated to past recharge by air masses coming from the Atlantic Ocean. Current recharge is assumed almost nil but it was significant in past wetter-than-present periods, increasing groundwater reserves, which are not yet exhausted. To explain the observed chloride content and radiocarbon (14C) activity, a well-mixed (exponential) flow model has been considered for aquifer recharge. The average residence time of groundwater feeding the springs has been estimated between 1 and 2 kyr, up to 5 kyr and between 7 and 13 kyr for deep well water, assuming that current recharge is much less than during the previous wetter period. The recharge period feeding the coastal springs could have been produced 1 to 5 kyr BP, when the area was already inhabited, and recharge in the Michilla mine was produced during the 10 to 14.5 kyr BP CAPE (Central Andean Pluvial Event) pluvial events of the central Andes. The approximate coincidence of turnover time with the past wet periods, as revealed by paleoclimate data, points to significant recharge during them.
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
Arashiro, L.; Montero, N.; Ferrer, I.; Acién, F.; Gómez, C.; Marianna Garfi' Science of the total environment Vol. 622-623, p. 1118-1130 DOI: 10.1016/j.scitotenv.2017.12.051 Fecha de publicación: 2018-05 Artículo de revista
The aim of this study was to assess the potential environmental impacts associated with high rate algal ponds (HRAP) systems for wastewater treatment and resource recovery in small communities. To this aim, a Life Cycle Assessment (LCA) was carried out evaluating two alternatives: i) a HRAP system for wastewater treatment where microalgal biomass is valorized for energy recovery (biogas production); ii) a HRAP system for wastewater treatment where microalgal biomass is reused for nutrients recovery (biofertilizer production). Additionally, both alternatives were compared to a typical small-sized activated sludge system. An economic assessment was also performed. The results showed that HRAP system coupled with biogas production appeared to be more environmentally friendly than HRAP system coupled with biofertilizer production in the climate change, ozone layer depletion, photochemical oxidant formation, and fossil depletion impact categories. Different climatic conditions have strongly influenced the results obtained in the eutrophication and metal depletion impact categories. In fact, the HRAP system located where warm temperatures and high solar radiation are predominant (HRAP system coupled with biofertilizer production) showed lower impact in those categories. Additionally, the characteristics (e.g. nutrients and heavy metals concentration) of microalgal biomass recovered from wastewater appeared to be crucial when assessing the potential environmental impacts in the terrestrial acidification, particulate matter formation and toxicity impact categories. In terms of costs, HRAP systems seemed to be more economically feasible when combined with biofertilizer production instead of biogas. On the whole, implementing HRAPs instead of activated sludge systems might increase sustainability and cost-effectiveness of wastewater treatment in small communities, especially if implemented in warm climate regions and coupled with biofertilizer production.
Páramo-Kañetas, P.; Ozturk, U.; Calvo, J.; Cabrera, J.; Guerrero, M. Journal of materials processing technology Vol. 255, p. 204-211 DOI: 10.1016/j.jmatprotec.2017.12.014 Fecha de publicación: 2018-05-01 Artículo de revista
In this paper, we report an experimental study designed to examine how participants interpret and perceive social hints from gaze exhibited by either a robot or a human tutor when carrying out a matching task. The underlying notion is that knowing where an agent is looking provides cues that can direct attention, to an object of interest during a task. In this regard, we asked human participants to play a card matching game in the presence of either a human or a robotic tutor. In one case, the tutor gave hints to help the participant find the matching cards by gazing toward the correct match, in the other case, the tutor only looked at the participants and did not give them any help. The performance was measured based on the time and the number of tries taken to complete the game. Results show that gaze hints (helping tutor) made the matching task significantly easier (fewer tries) with the robot tutor. Furthermore, we found out that the robot's gaze hints were recognised significantly more often than the human tutor gaze hints, and consequently, the participants performed significantly better. The reported study provides new findings towards the use of non-verbal gaze hints in human-robot interaction, and lays out new design implications, especially for robots used for educative purposes.
Safarpoor, M.; Ghaedi, M.; Asfaram, A.; Yousefi, M.; Javadian, H.; Zare, H. Ultrasonics sonochemistry Vol. 42, p. 76-83 DOI: 10.1016/j.ultsonch.2017.11.001 Fecha de publicación: 2018-04-01 Artículo de revista
There is a great interest in increasing the amount of recycled material used in asphalt mixes because of the beneficial impact on the environment. This is leading to the development of different recycling procedures, from cold in-situ to hot in-plant recycling. The objective of the study presented in this paper is to evaluate cracking resistance of recycled mixes manufactured by three types of processes, i.e., cold with emulsion, hot with high penetration bitumens and hot with emulsion (half-warm mixture), using 100% of reclaimed asphalt pavement (RAP) at different temperatures. Differences in their workability and ease of use are also analysed by gyratory compaction.
Sandoval, D.A.; Rinaldi, A.; Tarragó, J.M.; Roa, J.J.; Fair, J.; Llanes, L. International journal of refractory metals and hard materials Vol. 72, p. 157-162 DOI: 10.1016/j.ijrmhm.2017.12.029 Fecha de publicación: 2018-04-01 Artículo de revista
The water drained in mining operations (galleries, shafts, open pits) usually comes from different sources. Evaluating the contribution of these sources is very often necessary for water management. To determine mixing ratios, a conventional mass balance is often used. However, the presence of more than two sources creates uncertainties in mass balance applications. Moreover, the composition of the end-members is not commonly known with certainty and/or can vary in space and time. In this paper, we propose a powerful tool for solving such problems and managing groundwater in mining sites based on multivariate statistical analysis. This approach was applied to the Cobre Las Cruces mining complex, the largest copper mine in Europe. There, the open pit water is a mixture of three end-members: runoff (RO), basal Miocene (Mb) and Paleozoic (PZ) groundwater. The volume of water drained from the Miocene base aquifer must be determined and compensated via artificial recharging to comply with current regulations. Through multivariate statistical analysis of samples from a regional field campaign, the compositions of PZ and Mb end-members were firstly estimated, and then used for mixing calculations at the open pit scale. The runoff end-member was directly determined from samples collected in interception trenches inside the open pit. The application of multivariate statistical methods allowed the estimation of mixing ratios for the hydrological years 2014–2015 and 2015–2016. Open pit water proportions have changed from 15% to 7%, 41% to 36%, and 44% to 57% for runoff, Mb and PZ end-members, respectively. An independent estimation of runoff based on the curve method yielded comparable results.
Ridaura, G.; Llorens, S.; Carrillo, C.; Buj, I.; Riba Romeva, C. Resources, conservation and recycling Vol. 131, p. 75-85 DOI: 10.1016/j.resconrec.2017.10.030 Fecha de publicación: 2018-04-01 Artículo de revista
Hosseini Asl, S.; Ghadi, A.; Sharifzadeh Baei, M.; Javadian, H.; Maghsudi, M.; Kazemian, H. Fuel (Guildford) Vol. 217, p. 320-342 DOI: 10.1016/j.fuel.2017.12.111 Fecha de publicación: 2018-04-01 Artículo de revista
Roitero, E.; Ochoa, M.; Anglada, M.; Mücklich, F.; Jimenez-Pique, E. Journal of the european ceramic society Vol. 38, num. 4, p. 1742-1749 DOI: 10.1016/j.jeurceramsoc.2017.10.044 Fecha de publicación: 2018-04 Artículo de revista
The aim of this study is to characterize the resistance to low temperature degradation (LTD) of the surface of dental-grade zirconia (3Y-TZP) patterned with a Nd:YAG laser (532. nm harmonic and pulse duration of 10. ns) employing an interference setup.Laser patterning decreases the resistance to LTD of 3Y-TZP because of the presence of monoclinic phase and residual stresses, induced by the thermal shock during laser-material interaction. A thermal treatment (1. h at 1200. °C) anneals the affected microstructure and increase the resistance to LTD of laser patterned 3Y-TZP. Transformation delay may be attributed to monoclinic phase reversion, texture in the tetragonal phase and the existence of a net of shallow microcracks on the surface, accommodating autocatalytic transformation.
Petit-Boix, A.; Devkota, J.; Phillips, R.; Vargas Parra, Maria Violeta; Josa, A.; Gabarrell, X.; Rieradevall, J.; Apul, D. Science of the total environment Vol. 621, p. 434-443 DOI: 10.1016/j.scitotenv.2017.11.206 Fecha de publicación: 2018-04 Artículo de revista
Water management plays a major role in any city, but applying alternative strategies might be more or less feasible depending on the urban form and water demand. This paper aims to compare the environmental performance of implementing rainwater harvesting (RWH) systems in American and European cities. To do so, two neighborhoods with a water-stressed Mediterranean climate were selected in contrasting cities, i.e., Calafell (Catalonia, Spain) and Ukiah (California, US). Calafell is a high-density, tourist city, whereas Ukiah is a typical sprawled area. We studied the life cycle impacts of RWH in urban contexts by using runoff modeling before (i.e. business as usual) and after the implementation of this system. In general, cisterns were able to supply > 75% of the rainwater demand for laundry and toilet flushing. The exception were multi-story buildings with roofs smaller than 200 m2, where the catchment area was insufficient to meet demand. The implementation of RWH was environmentally beneficial with respect to the business-as-usual scenario, especially because of reduced runoff treatment needs. Along with soil features, roof area and water demand were major parameters that affected this reduction. RWH systems are more attractive in Calafell, which had 60% lower impacts than in Ukiah. Therefore, high-density areas can potentially benefit more from RWH than sprawled cities.
Planning motions to grasp an object in cluttered and uncertain environments is a challenging task, particularly when a collision-free trajectory does not exist and objects obstructing the way are required to be carefully grasped and moved out. This letter takes a different approach and proposes to address this problem by using a randomized physics-based motion planner that permits robot–object and object–object interactions. The main idea is to avoid an explicit high-level reasoning of the task by providing the
motion planner with a physics engine to evaluate possible complex multibody dynamical interactions. The approach is able to solve the problem in complex scenarios, also considering uncertainty in the objects’ pose and in the contact dynamics. The work enhances the state validity checker, the control sampler, and the tree exploration strategy of a kinodynamic motion planner called KPIECE. The enhanced algorithm, called p-KPIECE, has been validated in simulation and with real experiments. The results have been compared with an ontological physics-based motion planner and with task and motion planning approaches, resulting in a significant improvement in terms of planning time, success rate, and quality of the solution path.
Chronic wounds represent a challenge to wound care professionals consuming a great deal of healthcare resources and, at the same time, reducing patient life quality with increased hospitalization times, heavy pain and eventually sepsis and death. Heavy bacterial colonisation is the main reason for non-healing chronic wounds, consequently wounds are often treated with antibiotics prophylactically, thus leading to unnecessary selection for bacterial resistance. Hence, there is a need for point of care testing (PoCT) devices for the evaluation of infection biomarkers allowing an early and appropriate treatment to reduce the severity of the disease and avoid the chronicity. In the last decade, paper based PoCT devices has showed great potential with the development of cheap and versatile microfluidic and lateral flow devices. These devices incorporate sensing molecules (e.g. enzyme substrates) immobilized in specific spots within the paper platform where they will react with determined biomarkers when the liquid sample flows through the device. Myeloperoxidase (MPO) an enzyme secreted by neutrophils and detected in fluids of infected wounds has been postulated as a suitable biomarker for wound diagnostics. MPO catalyzes the oxidation of chloride ions to hypochlorous acid (HClO), a powerful bactericidal oxidant, using hydrogen peroxide as co-substrate. At the same time, MPO can oxidize a variety of molecules including phenols, quinones, hydrazines and also proteins. Taking advantage of MPO substrate promiscuity, here we present an unexplored system for MPO detection based on enzyme-catalysed oxidative dye polymerization which can be incorporated into paper-based PoCT devices. Visual MPO detection has been achieved through the use of phenylenediamines, a common dye component, which its oxidation byMPO yielded bright coloured products distinguishable from the colour of the wound environment. Using paper strips as model of paper-based lateral flow device, immobilisation of the dye substrate was achieved through in situ interaction of the oxidised coloured product with a polycationic polymer. The colour reaction of the immobilised substrates, detectable by naked eye, responds to the MPO levels present in infected wound fluids. Thus revealing an easy system for incorporation of MPO detection in paper based diagnostic devices.
Bacteria-mediated diseases are a global healthcare concern due to the development and spread of antibiotic resistant strains. Cationic compounds are considered membrane active biocidal agents having a great potential to control bacterial infections, while limiting the emergence of drug resistance. Herein, the versatile and simple Layer-by-Layer (LbL) technique was used to coat alternating multilayers of an antibacterial aminocellulose conjugate and the biocompatible hyaluronic acid on biocompatible polymer nanoparticles (NPs), taking advantage of the nano-size of these otherwise biologically inert templates. Stable polyelectrolyte-decorated particles with an average size of 50 nm and zeta potential of + 40.6 mV were developed after five LbL assembly cycles. The antibacterial activity of these NPs against the Gram-positive Staphylococcus aureus and Gram- negative Escherichia coli increased significantly when the polycationic aminocellulose was in the outermost layer. The large number of amino groups available on the particles surface, together with the nano-size of the multilayer conjugates, improved their interaction with bacterial membrane phospholipids leading to membrane disruption, as confirmed by a Langmuir monolayer model, and the 10 logs bacterial reduction. The biopolymer decorated NPs were also able to inhibit the biofilm formation of Staphylococcus aureus and Escherichia coli by 99 and 40 %, respectively, without affecting human cells viability. The use of LbL coated NPs appears as a promising antibiotic-free alternative for controlling bacterial infections using low amount of antimicrobial agent.
Silver nanoparticles (Ag-NPs) have been among the most commonly used nano-materials in our health care system, widely used in a range of biomedical applications, including diagnosis, treatment, drug delivery, medical device coating and for personal health care. Ag-NPs present unique physicochemical properties such as antibacterial, antifungal, antiviral and anti-inflammatory activity. In this matter, bionanocomposites materials, formed by the combination of natural polymers and inorganic components, like hybrid Ag-NPs, represents an important stake in scientific research offering the combined properties inherent to the natural biopolymers and inorganic nanoparticles. Meanwhile, hyaluronic acid (HA), an immunoneutral polysaccharide ubiquitously present in the human body, is an attractive starting materials since can be chemically modified through its reactive functional groups and transformed into many physical forms (viscoelastic solutions, soft or stiff hydrogels or even nanoparticulate fluids) as a biocompatible platform for a wide range of biomedical applications.
Multifunctional hydrogels were enzymatically generated by the crosslinking reaction between silver lignin nanoparticles (Ag-Lig NPs) and thiolated hyaluronic acid (HA-SH). First, Ag-lig NPs were synthesized using a green, eco-friendly procedure from aqueous AgNO3 solution with lignin, one of the most abundant biopolymers in nature, serving as a dual reducing and capping agent. Afterwards, the multiple functional groups present in lignin, mainly phenolic hydroxyls, serve as reactive groups to crosslink with thiol groups from HA by the action of the enzyme laccase. The morphology, swelling properties, and rheological characteristics of the performed HA hydrogels with embedded Ag-lig NPs together with their stability, control over MMP and MPO and cellularROS scavenging were investigated. Finally, the potential toxicology, the silver release from the hydrogel matrix, the anti-inflammatory effect and the antibacterial activity in front of different bacterial stains were addressed to explore their potential biomedical applications.
The main objective of this paper is to introduce an academic example on the use of histograms to develop a wind turbine blade fault (or damage) detection system. This approach merely uses data analysis
obtained from a generated wind turbine power. Then, and
based on the power curve of a wind turbine, histograms are
obtained, first, for the healthy wind turbine operation, and
then, for two cases on faulty wind turbine operations. By
comparing them, a faulty behaviour of a wind turbine is
detectable. Finally, according to our numerical example,
the proposed technique seems a realistic case to students
on the statistic and probability fields as a useful academic
An important preventive measure to avoid nosocomial infections is introducing highly efficient and durable antibacterial textiles and medical devices, e.g. catheters, into the hospital. Coatings of metal oxide (MeO) nanoparticles (NPs), such as ZnO, would ensure excellent antimicrobial properties of these products at minor cytotoxicity. Ultrasound (US) is an easy, fast and environmentally friendly surface nano-coating technology able to synthesize and deposit in a single step antimicrobial NPs on material’s surface.
We applied hydrolytic enzymes, i.e. cellulases, to coat cotton fabrics with ZnO NPs via US irradiation either in a two-step process for cellulose pre-activation, followed by sonochemical deposition of ZnO NPs, or in a one- step sono-enzymatic process to simultaneously activate cellulose and deposit ZnO NPs achieving high durability of the antimicrobial effect.
Further, we developed durable and efficient antibacterial coatings on medical textiles by depositing antibacterial ZnO NPs and gallic acid (GA) in a single-step laccase/US process. The rationale behind this sono-enzymatic approach was the in situ synthesis, upon the enzymatic oxidation of GA, of a bio-adhesive, in which the ZnO NPs are firmly embedded on the fabric surface. Additionally, a synergistic improvement of the antibacterial efficiency of lower amount ZnO NPs by the natural antimicrobial agent GA was achieved.
We also used US for coating of silicone catheters with hybrid enzyme/ZnO NPs. The antibacterial and anti- biofilm efficiency of the coated fabrics and catheters were validated against major clinically relevant bacterial pathogens. The sonochemical NP-coating technology was scaled-up into pilots that currently are being upgraded under the EU-FP7 project PROTECT into pre-commercial coating lines installed at Klopman Int. (Italy) and Degania Silicone (Israel) for production of antimicrobial textiles, water treatment membranes and catheters.
The emergence of drug-resistance microbial pathogens is creating a worldwide healthcare problem. Nanoparticles have been increasingly used as alternative to the antibiotics. Antimicrobial nanoparticles offers a platform against bacteria, viruses, fungus and protozoa and perform this activity by destroying cell membranes, blocking enzyme pathways, altering microbial cell wall, metabolic pathways and protein, DNA expression and acting on components from the extracellular matrix of biofilms. The advantages of the antimicrobial nanoparticles reside in their different mechanisms of action against pathogens, e.g. oxidative stress, metal ion release, or non-oxidative mechanism, which can occur simultaneously. These mechanisms are less likely to cause the appearance of microbial resistance.
Bacterial biofilms are structured, coordinated communities with distinct architectures and properties. They are ubiquitous in nature and possess the sophisticated ability to rapidly adapt and propagate in a wide variety of habitats. Microbial biofilms are at the root of many chronic and recurrent infections and their formation have been estimated to account for 80 % of all microbial infections currently treated in hospitals. Biofilm can grow on any foreign object inserted into the human body but also in different surfaces of the hospital premises.
In this study, we synthesized hybrid enzyme-metal nanoparticles combining the synergistic activities of different antimicrobial agents. The enzyme in the hybrid nano-entities acts on the extracellular components secreted by the bacterial populations to eliminate and to inhibit the formation of biofilm. On the other hand, the biocidal properties of the nanoparticle are provided by the metal counterpart in the naoparticulate composite. This antimicrobial approach could be applied in the form of coatings on surfaces such as hospital textiles, water treatment membranes and implantable medical devices, ensuring a safer environment for both patients and healthy population.
The occurrence of drug resistance is global healthcare concern, and although new drugs are constantly being sought, the pace of development is slow compared to the evolution and spread of multidrug resistant bacteria. The high persistence of bacteria in the form of both planktonic cells and biofilms on living tissues and medical surfaces calls for novel antibacterial strategies for the prevention and treatment of bacterial infections. In this study, enzymatic disruption of bacterial quorum sensing by acylase and ultrasound assisted nanospherization were innovatively combined to enhance the bactericidal e ffi cacy of the conventional antibiotic gentamicin, lowering the drug dosage. The generated hybrid nanoantibacterials were stable, with zeta potential – 40 ± 0.23 mV and size of 200 ± 1nm. They possessed membrane disrupting capacity and killed the medically relevant Gram-negative Pseudomonas aeruginosa bacteria after 45 min. The synergistic combination demonstrated improved antibiofilm activity compared to the individual counterparts and reduced the resistant P. aeruginosa biofilm up to 6 logs. Moreover, the bactericidal e ffi caicy of the hybrids was not drastically a ff ected in “protein corona” conditions, demonstrating their real application scenario. Further in situ ultrasound assisted synthesis and deposition of the acylase enzyme and gentamicin onto the surface of urinary catheters increased the life span of the medical devices and decreased the occurrence of bacterial biofilms. The obtained hybrid nanoantibacterials with complimentary modes of action were not found innocuous towards human fibroblasts (BJ-5ta cells) and as a such might be valuable alternative to control bacterial diseases at reduced antibiotic dosages.
Osteoarthritis (OA) is a degenerative disease characterised with pain, stiffness and loss of function in the weight-bearing joints, caused by the inflammatory biological molecules that disturb the balance between the tissue synthesis and degradation. Maintaining the composition of the physiological lubricant, named synovial fluid, by restoration of homeostasis is thus a necessary step to retard the OA progression and provide a suitable environment for tissue remodelling.
Thiolated hyaluronic acid (HA-SH) was enzymatically crosslinked with gallic acid (GA) by the action of laccase as a method to prepare multifunctional hydrogels, designed as delivery systems that enable long-term efficiency of biological entities in cell-based therapies. Owing to its characteristics and mild conditions employed, the encapsulation of very unstable and sensitive cargoes is possible, highlighting its potential as a platform for a variety of biomedical applications. A cytokine cocktail (ACC) and chondrocytes cells were encapsulated together as therapy to delay the disease progression and boost the anabolic pathways for recovery of the damaged cartilage. The morphology, swelling ratio, rheological properties and stability of the hydrogels were characterised and optimised in order to fit the requirements of the therapy. The efficiency of the developed platforms was evaluated in vitro against the major factors governing the OA disease, namely the anti-inflammatory effect, cellular ROS scavenging and the inhibitory capacity of the hydrogels towardsdeleterious enzymes as MMPs, MPO and hyalurodinase. Finally, experiments to determine the ability of the cells to survive, growth and differentiate in the multifunctional hydrogels were assessed in order to explore their potential in a cell-based therapies and regenerative medicine.
This paper introduces a new vehicle routing problem that arises in an urban area where several carriers operate and some of their customers have demand of service for more than one carrier. The problem, called Shared Customer Collaboration Vehicle Routing Problem, aims at reducing the overall operational cost in a collaboration framework among the carriers for the service of the shared customers. Alternative mathematical programming formulations are proposed for the problem that are solved with a branch-and-cut algorithm. Computational experiments on different sets of benchmark instances are run to assess the effectiveness of the formulations. Moreover, in order to estimate the savings coming from the collaboration, the optimal solutions are compared with the solutions obtained when carriers work independently from each other.
Fernandez de Labastida, M.; Licon, E.; Bondarenko, M.; Yaroshchuk, A. Journal of membrane science num. 550, p. 492-501 DOI: 10.1016/j.memsci.2017.10.057 Fecha de publicación: 2018-03-15 Artículo de revista
This work presents a new approach to correcting for concentration polarization (CP) in pressure-driven membrane measurements. In the existing test cells (both cross-flow and stirred-batch) there are distributions of extent of CP over membrane surface. This complicates the interpretation of experimental data.A novel design of test cell with equally-accessible membrane surface has been developed based on the classical configuration of rotating disk combined with the possibility of applying trans-membrane hydrostatic pressure differences of up to 20. bar. Due to the equal accessibility, corrections for CP can easily be made even in multi-ionic systems, which would be much more difficult with other membrane test cells.Since the membrane has to be sealed at the edge the geometry somewhat deviates from the ideal case of infinite disk. The impact of these deviations has been quantified via CFD simulations. A major part of the membrane surface is shown to be equally accessible while there are some expectable deviations close to the sealed membrane edge. This zone could be “screened“ in the experiments. The approach could also be validated experimentally via studying the dependence of observed rejection on the rotation speed and demonstrating that intrinsic rejection was practically independent of it.Finally, to demonstrate the cell utility, we performed and interpreted a number of experiments using commercial NF270 membrane and various feed solutions (single salts and electrolyte mixtures). We conclude that this cell can be employed for systematic transport characterization of membranes and the obtained information can be used as input in the CFD modelling of membrane modules.
Lopez, J.; Reig, M.; Yaroshchuk, A.; Licon, E.; Gibert, O.; Cortina, J. Journal of membrane science Vol. 550, p. 389 DOI: 10.1016/j.memsci.2018.01.002 Fecha de publicación: 2018-03-15 Artículo de revista
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.
Del Barrio, M.; Levit, R.; Lloveras, P.; Aznar, A.; Negrier, P.; Mondieig, D.; Tamarit, J. Ll. Fluid phase equilibria Vol. 459, p. 219-229 DOI: 10.1016/j.fluid.2017.07.020 Fecha de publicación: 2018-03-15 Artículo de revista
The temperature-composition phase diagram of the two-component system 1-Br-adamantane and 1-Cl-adamantane has been determined by means of thermal analysis techniques and X-ray powder diffraction from the low-temperature phase to the liquid state.
The crossed isopolymorphism formalism has been applied to the two-component system to infer the normal pressure properties of the orthorhombic metastable phase of 1-Cl-adamantane at normal pressure. The experimental pressure-temperature phase diagrams for the involved compounds are related to the two-phase equilibria determined at normal pressure and inferences about the monotropic behavior of the aforementioned orthorhombic phase are discussed.
This paper aims to present a novel methodology that permits to determine the optimal retrofitting actions to be implemented in a given building of the tertiary sector, based on its architectonic characteristics (e.g. volume, useful area, orientation, walls thermal transmittance, etc.), climatic conditions (i.e. solar radiation, temperature) and operation profiles. The proposed methodology has been developed by the technological centers "Eurecat" and "Fundació CTM Centre Tecnològic", in the framework of two national research projects.
The proposed methodology is based on the combination of mathematical models that characterize the annual energy demand vectors of a given building based on its characteristics, and the use of an evolutionary-based optimization algorithms to evaluate the different (available) retrofitting actions for both the passive and active part of the building, with objective to determine the optimal ones in terms of energy efficiency, investment and maintenance cost and GHG emissions reduction.
The proposed methodology has been developed as a beta software tool for windows-based operating systems, which through a simplified graphic user interface permits the customization of the databased, the configuration of the building's characteristics, as well as the evaluation and optimization of different retrofitting actions in both the passive and active parts of a given building. Finally, it presents graphically and numerically the obtained results.
Sanmiquel, L.; Bascompta, M.; Rossell, Josep M.; Anticoi, H.; Guasch, E. International journal of environmental research and public health Vol. 15, num. 3, 462, p. 1-11 DOI: 10.3390/ijerph15030462 Fecha de publicación: 2018-03-07 Artículo de revista
An analysis of occupational accidents in the mining sector was conducted using the data from the Spanish Ministry of Employment and Social Safety between 2005 and 2015, and data-mining techniques were applied. Data was processed with the softwareWeka. Two scenarios were chosen from the accidents database: surface and underground mining. The most important variables involved in occupational accidents and their association rules were determined. These rules are composed of several predictor variables that cause accidents, defining its characteristics and context. This study exposes the 20 most important association rules in the sector—either surface or
underground mining—based on the statistical confidence levels of each rule as obtained byWeka.
The outcomes display the most typical immediate causes, along with the percentage of accidents with a basis in each association rule. The most important immediate cause is body movement with
physical effort or overexertion, and the type of accident is physical effort or overexertion. On the other hand, the second most important immediate cause and type of accident are different between
the two scenarios. Data-mining techniques were chosen as a useful tool to find out the root cause of the accidents.
Carrillo, F.; Casadesus, M.; Macanás, J.; Colom, X.; Cañavate, J.; M.D. Alvarez; Garrido, N.; Molins, G. AATCC International Conference p. 1-2 Fecha de presentación: 2018-03-07 Presentación de trabajo en congreso
Changing conditions and variations in the demand are frequent in real industrial environments. Decision makers have to take into account this uncertainty and manage it properly. One clear example is the automotive industry where manufacturers have to assume an uncertain and heterogeneous demand. For instance, automotive manufacturers must adapt their decisions when balancing the assembly line by considering different flexible solutions. Our proposal is using robust multiobjective optimization and simulation techniques to provide managers with a set of robust and equally-preferred solutions for assembly line balancing. We study a Nissan case where the demand of each product family is uncertain. The problem is addressed by considering a robust multiobjective model for assembly line balancing based on a high number of production plans. After the selection of six different assembly line configurations, we study the implications of robustness metrics based on workstations’ overload. We show that the adverse managerial effects of not having flexible line configuration when demand changes are alleviated. For the real Nissan automotive case, our analysis and conclusions show the managerial and industrial benefits of using robust assembly lines. We also encourage decision makers to use robust multiobjective optimization methods for selecting the most flexible decisions.
Sanchez-arcilla, A.; Gracia, V.; Marzeddu, A.; Gironella, X.; Garcia, M.; Sánchez-Arcilla Jr., A. Congreso Transfronterizo sobre Cambio Climático y Litoral p. 37 Fecha de presentación: 2018-03-06 Presentación de trabajo en congreso
La intensificación de la presión de uso sobre nuestro litoral está generando un incremento de los niveles de riesgo, entendido como la probabilidad de un suceso por el valor económico de sus consecuencias. El aumento del nivel del mar y los cambios en las características del oleaje, inducidos por el cambio climático no harán más que agravar tal situación. El carácter no intrusivo de las técnicas de observación por imágenes ofrece grandes ventajas para la auscultación de los procesos costeros, al estar ubicados los sensores fuera de un medio tan dinámico como es la zona costera, especialmente la de rompientes donde las solicitaciones sobre estructuras y sensores son máximas.
El uso de imágenes de video en el mar ha experimentado un rápido auge en estos últimos años debido entre otras cosas a los siguientes factores: a) abaratamiento en los costes de adquisición asociados (Nieto et al. 2010); b) la incorporación de nuevas variables hidro-morfodinámicas (Almar et al., 2011; Benassai et al., 2017; Rodier et al., 2017); c) la mejora en la resolución de las imágenes y el desarrollo de nuevas técnicas (Andriolo et al., 2016; Valentini et al., 2016; Pitman et al., 2016) ópticas en laboratorio. Este último punto ha permitido reproducir la geometría 3D de un objeto con resolución por debajo del centímetro y por tanto con aplicaciones para el caso de las secciones transversales de diques o espigones (Marzeddu et al., 2017). En paralelo, los avances obtenidos en el campo del modelado numérico han permitido desarrollar sistemas de alerta costera enfocados a distintas peligrosidades (proyectos europeos MICORE, i-Coast, RISKIT entre otros) y la elaboración de mapas de peligrosidades a distintas escalas.
En este trabajo se planteará el uso de imágenes ópticas convencionales, procesadas mediante software libre y de Autodesk, de donde resulta una estimación directa de los valores geométricos que caracterizan una superficie en 3D. A partir de aquí, con el complemento de información temporalmente promediada tal y como se utiliza habitualmente en playas (De Santiago et al., 2013) y con simulaciones numéricas de la hidro-morfodinámica correspondiente (Dae-Hong et al., 2017; Sanchez-Arcilla et al., 2014; Sierra et al., 2017) es posible obtener mapas de riesgo para distintos eventos meteo-oceanográficos. Estos mapas se han obtenido de manera offline para distintas playas micro-mareales en Cataluña en condiciones de calma y tormenta, calculando los riesgos de erosión e inundación.
En el artículo se analizará la posibilidad de extender esta metodología a reconstrucciones 3D de la superficie del mar y a mapas de riesgos en tiempo real para playas micro y macro-mareales, a partir de las imágenes y resultados ya disponibles. También se valorará la aplicación de la metodología para obtener niveles de calidad en otras funciones del dominio playero, como puede ser la práctica del surf o el uso lúdico de la playa sumergida en general. Todo ello de manera semiautomática, de manera que permita una caracterización del riesgo en condiciones presentes y también la generación de una secuencia de mapas e imágenes para escenarios futuros.
Sorolla, S.; Flores, A.; Canals, T.; Cantero, M.R.; Font Vallès, Joaquim; Olle, L.; Bacardit, A. Journal of the American Leather Chemists Association Vol. 113, num. 3, p. 88-93 Fecha de publicación: 2018-03-05 Artículo de revista
The main aim of this study is to carry out a qualitative and semiquantitative analysis of tannin extracts as an alternative to the official analysis method ISO 14088 – IUC 32, so that a correlation between the two methods is established.
From the point of view of the chemical composition, tannins are classified into two major groups: i) condensed tannins, also called flavanols or catechins, and ii) hydrolysable tannins, also called pyrogallic tannins.
Today, the most widely used conventional extracts are quebracho, mimosa, chestnut, and tara. Quebracho and mimosa are condensed tannins, whereas chestnut and tara are hydrolysable tannins.
The following extracts were used in this study: tara powder, commercial mimosa and quebracho extracts and extracts derived from grape seed, containing both condensed and hydrolysable extracts.
The development of this new method will allow a faster and less expensive estimate of the amount of tannins present in a tannin extract.
Ruiz Gironès , E.; Oliver , A.; Socorro, G.; Cascón, J.; Escobar, J.M.; Montenegro, R.; Sarrate, J. International journal for numerical methods in engineering Vol. 113, p. 1488-1506 DOI: 10.1002/nme.5706 Fecha de publicación: 2018-03-02 Artículo de revista
In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high-quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.
This is the peer reviewed version of the following article: Ruiz Gironès , E., Oliver , A., Socorro, G., Cascón, J., Escobar, J.M., Montenegro, R., Sarrate, J. Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures. "International journal for numerical methods in engineering", 2018, which has been published in final form at http://onlinelibrary.wiley.com/doi/10.1002/nme.5706/pdf. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.