The relevance of higher education institutions (HEI) for social development is
unquestionable because of their potential for contributing intellectual solutions for
the social, economic, and environmental welfare of society. The current study
aims to: 1) examine which are the main catalysts of university social responsibility
(USR) from a strategic management perspective; 2) show the relations among
those catalysts through semantic networks; and 3) analyse the role of university
promotion of entrepreneurship. The method uses a content analysis in a sample of
23 universities and examines the subject and codes to clarify the catalysts. The
semantic networks are shown to reveal these connections. It was found that a high
percentage of universities orient their efforts towards enhancing the employability
of students, mainly through entrepreneurial projects intended to achieve social
The implementation of University Social Responsibility (USR) in its strategic plans is
a subject of great social interest. However, the lack of understanding produces deficient stakeholder’s engagement, obstructing USR applications and potential benefits. USR in a formal context and as part of strategy should be a path that leads to its fulfilment. A Delphi method was used and several experts have participated in it. Results show that USR is related to student’s issues, among main drivers are to work under a code of ethics and acquire civic competences as a part of their vocational training. Among barriers to be involved in social responsibility activities is the lack of engagement of university community. The insufficient
communication into the university community is mentioned as one of the main
obstacles to incorporate USR into strategic planning. Relevance of this work relies on the holistic points of views of the results.
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 Data de presentació: 2018-09-27 Presentació treball a congrés
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 Data de publicació: 2018-07 Article en 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 Data de publicació: 2018-05-15 Article en 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.
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 Data de publicació: 2018-05-01 Article en revista
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.
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 Data de publicació: 2018-05 Article en 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.
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.
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 Data de publicació: 2018-04-01 Article en 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 Data de publicació: 2018-04-01 Article en revista
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 Data de publicació: 2018-04 Article en 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.
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 Data de publicació: 2018-04-01 Article en revista
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 Data de publicació: 2018-04-01 Article en 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.
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.
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.
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 Data de publicació: 2018-03-15 Article en 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.
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.
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 Data de publicació: 2018-03-15 Article en 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.
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.
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 Data de publicació: 2018-03-05 Article en 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 Data de publicació: 2018-03-02 Article en 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.