On the Use of Graphs for Node Connectivity in Wireless Sensor Networks for Hostile Environments

[EN] Wireless sensor networks (WSNs) have been extensively studied in the literature. However, in hostile environments where node connectivity is severely compromised, the system performance can be greatly affected. In this work, we consider such a hostile environment where sensor nodes cannot directly communicate to some neighboring nodes. Building on this, we propose a distributed data gathering scheme where data packets are stored in different nodes throughout the network instead to considering a single sink node. As such, if nodes are destroyed or damaged, some information can still be retrieved. To evaluate the performance of the system, we consider the properties of different graphs that describe the connections among nodes. It is shown that the degree distribution of the graph has an important impact on the performance of the system. A teletraffic analysis is developed to study the average buffer size and average packet delay. To this end, we propose a reference node approach, which entails an approximation for the mathematical modeling of these networks that effectively simplifies the analysis and approximates the overall performance of the system.The authors wish to thank the Consejo Nacional de Ciencia y Tecnologia (CONACyT), the Comision de Operacion y Fomento de Actividades Academicas, Instituto Politecnico Nacional (COFAA-IPN, project numbers 20196225 and 20196678), and the Estimulos al Desempeno de los Investigadores del Instituto Politecnico Nacional (EDI-IPN) for the support given for this work. The work of V. Pla was supported by Grant PGC2018-094151-B-I00 (MCIU/AEI/FEDER, UE).García-González, E.; Chimal-Eguía, JC.; Rivero-Angeles, ME.; Pla, V. (2019). On the Use of Graphs for Node Connectivity in Wireless Sensor Networks for Hostile Environments. Journal of Sensors. 2019:1-22. https://doi.org/10.1155/2019/7409329S1222019Eren, T. (2017). The effects of random geometric graph structure and clustering on localizability of sensor networks. International Journal of Distributed Sensor Networks, 13(12), 155014771774889. doi:10.1177/1550147717748898Clauset, A., Shalizi, C. R., & Newman, M. E. J. (2009). Power-Law Distributions in Empirical Data. SIAM Review, 51(4), 661-703. doi:10.1137/070710111Hakimi, S. L. (1962). On Realizability of a Set of Integers as Degrees of the Vertices of a Linear Graph. I. Journal of the Society for Industrial and Applied Mathematics, 10(3), 496-506. doi:10.1137/011003

Study of erosion behaviour of conventional and nanostructured WC-12Co coatings sprayed by atmospheric plasma

Thermal sprayed WC-Co coatings are used extensively to enhance the wear resistance of a wide range of engineering components. In this paper, erosive resistance of plasma atmospheric sprayed WC-12Co coatings has been evaluated. Solid particle erosion tests were conducted on these coatings at different angles of impact with silica and alumina abrasives of size 250 µm. Coatings have been deposited by using micrometric and nanometric agglomerated powders, employing H2 and He as plasmogen gas. In order to determine the erosion regime (ductile or brittle), the influence of impact angle on the erosion rate has been studied. Optical microscope and FESEM have been used to analyze the eroded surface. The influence of the plasmogen gas and the powder employed on the erosive behaviour of the coating has been evaluated. An attempt to connect the erosive behaviour with mechanical properties and microstructure has been made. Hardness has been determined by means of several measurements of Vickers microhardness; fracture toughness has been estimated through indentation method. Identification of phases has been made by means of X Ray diffractio

Novel compatibilizers and plasticizers developed from epoxidized and maleinized chia oil in composites based on PLA and chia seed flour

[EN] Novel compatibilizers and plasticizers derived from epoxidized chia seed oil (ECO) and maleinized chia seed oil (MCO) have been applied in composites based on poly(lactic acid) (PLA) and 15 wt% chia seed flour (CSF). Results obtained have been compared to conventional silane coupling agent, (3-glycidyloxypropyl) trimethoxysilane (GPS), and a petroleum-based compatibilizer, poly(styrene-co-glycidyl methacrylate) copolymer (Xibond, (R)). The compatibilization effect of green composites were assessed by FTIR. The addition of all four compatibilizers improved the ductile mechanical and thermal properties of the composites. The morphology analysis revealed an improvement of interfacial adhesion of the CSF particles into the PLA matrix. In particular, ECO and MCO composites showed a roughness with long filaments in their morphology which plays a crucial role in improving the ductile properties highly. The elongation at break was 10 and 8 times higher using ECO and MCO, respectively, compared to uncompatibilized composite. Moreover, the composites manufactured showed low values (<9%) in the water uptake assay and a negligible compostability delay. The use of novel compatibilizers based on modified vegetable oils could mean an interesting proposal to obtain an entirely environmentally friendly composite with a remarkable ductile property.This research work was funded by the Ministry of Science and Innovation-¿Retos de la Sociedad¿. Project references: PID2020-119142RA-I00. I. Dominguez-Candela wants to thank Universitat Politècnica de València for his FPI grant (PAID-2019-SP20190013) and Generalitat Valenciana-GVA (ACIF/2020/233). J. Gomez-Caturla wants to thank Generalitat Valenciana-GVA, for his FPI grant (ACIF/2021/185) and grant FPU20/01732 funded by MCIN/AEI/10.13039/ 501100011033.Domínguez-Candela, I.; Gómez-Caturla, J.; Cardona, SC.; Lora-García, J.; Fombuena, V. (2022). Novel compatibilizers and plasticizers developed from epoxidized and maleinized chia oil in composites based on PLA and chia seed flour. European Polymer Journal. 173(111289):1-14. https://doi.org/10.1016/j.eurpolymj.2022.11128911417311128

ASSESSMENT OF STUDENTS IN THE USE OF MATLAB GUIDE TEMPLATES FOR SOLVING MATERIAL BALANCES. A TEACHING EXPERIENCE IN CHEMICAL ENGINEERING DEGREE

Domínguez-Candela, I.; Cardona, SC.; Lora-García, J.; López Pérez, MF.; Fombuena, V. (2021). ASSESSMENT OF STUDENTS IN THE USE OF MATLAB GUIDE TEMPLATES FOR SOLVING MATERIAL BALANCES. A TEACHING EXPERIENCE IN CHEMICAL ENGINEERING DEGREE. IATED Academy. 5926-5933. https://doi.org/10.21125/inted.2021.11885926593

Dual Plasticizer/Thermal Stabilizer Effect of Epoxidized Chia Seed Oil (Salvia hispanica L.) to Improve Ductility and Thermal Properties of Poly(Lactic Acid)

[EN] The use of a new bio-based plasticizer derived from epoxidized chia seed oil (ECO) was applied in a poly(lactic acid) (PLA) matrix. ECO was used due to its high epoxy content (6.7%), which led to an improved chemical interaction with PLA. Melt extrusion was used to plasticize PLA with different ECO content in the 0-10 wt.% range. Mechanical, morphological, and thermal characterization was carried out to evaluate the effect of ECO percentage. Besides, disintegration and migration tests were studied to assess the future application in packaging industry. Ductile properties improve by 700% in elongation at break with 10 wt.% ECO content. Field emission scanning electron microscopy (FESEM) showed a phase separation with ECO content equal or higher than 7.5 wt.%. Thermal stabilization was improved 14 degrees C as ECO content increased. All plasticized PLA was disintegrated under composting conditions, not observing a delay up to 5 wt.% ECO. Migration tests pointed out a very low migration, less than 0.11 wt.%, which is to interest to the packaging industry.I.D.-C. wants to thank Universitat Politecnica de Valencia for his FPI grant (PAID-2019-SP20190013) and Generalitat Valenciana (GVA) for his FPI grant (ACIF/2020/233). J.M.F. thanks the postdoc contract (APOSTD/2019/122) Generalitat Valenciana (2019-2021).Domínguez-Candela, I.; Ferri Azor, JM.; Cardona, SC.; Lora-García, J.; Fombuena, V. (2021). Dual Plasticizer/Thermal Stabilizer Effect of Epoxidized Chia Seed Oil (Salvia hispanica L.) to Improve Ductility and Thermal Properties of Poly(Lactic Acid). Polymers. 13(8):1-16. https://doi.org/10.3390/polym13081283S11613

Gravitational waves from galaxy encounters

We discuss the emission of gravitational radiation produced in encounters of dark matter galactic halos. To this aim we perform a number of numerical simulations of typical galaxy mergers, computing the associated gravitational radiation waveforms as well as the energy released in the processes. Our simulations yield dimensionless gravitational wave amplitudes of the order of $10^{-13}$ and gravitational wave frequencies of the order of $10^{-16}$ Hz, when the galaxies are located at a distance of 10 Mpc. These values are of the same order as those arising in the gravitational radiation originated by strong variations of the gravitational field in the early Universe, and therefore, such gravitational waves cannot be directly observed by ground-based detectors. We discuss the feasibility of an indirect detection by means of the B-mode polarization of the Cosmic Microwave Background (CMB) induced by such waves. Our results show that the gravitational waves from encounters of dark matter galactic halos leave much too small an imprint on the CMB polarization to be actually observed with ongoing and future missions.Comment: 9 pages with revtex style, 3 ps figures; to be published in Physical Review

HOW TO GUIDE CHEMICAL ENGINEERING STUDENTS IN THE SOLUTION OF COMPLEX ENGINEERING PROBLEMS

[EN] If we analyse some of the specific skills of Chemical Engineering degree, and it would not be very different in other disciplines of engineering, the verbs design, analyse or simulate stand out above all. In essence, calculating is an intrinsic activity for the engineer and, therefore, for engineering students. How is this activity developed? When we face a real problem we translate it into mathematical language (modelling). We solve the resulting mathematical problem to obtain the mathematical solution (simulation). The analysis of the results allows us to extract information from the real problem. If the interpretation of the results does not fit with the real problem studied, we must rethink the mathematical model obtained, and so on. Teachers often restrict the real problems that students face to simple situations so that the resulting mathematical problem is simple and, if possible, provides an analytical solution. Why should we do this today if we have numerical methods, a big computing power and mathematical software available to our students? Examples of complex mathematical problems arise from analysis and design of heat exchangers, chemical reactors, distillation columns, etc, both in steady and transitory regimes. These mathematical problems can be classified in groups: solving algebraic equations, ordinary differential equations or partial differential equations systems. According to this classification, some teachers of the Chemical Engineering degree at Campus of Alcoy are providing our students with Matlab guide templates to solve these types of mathematical problems, regardless of the subjects in which these problems appear. This action makes it easier for students to face real problems by reducing the mathematical difficulties associated. This paper shows how these Matlab guide templates are and how students use them in different subjects. It allows students to focus on the engineering aspect of the processes, leaving the difficulty of the associated mathematical problem in a second plane. It also makes easy to modify process parameters to quickly see the effect on the main variables of the process (what if? analysis). Consequently, students improve their ability to analyse and interpret the results obtained and their critical thinking skills. And, finally, they know useful computer tools that can be used both academically and professionallyCarbonell Alcaina, C.; Cardona, SC.; Domínguez-Candela, I.; Fombuena, V.; López Pérez, MF.; Lora-García, J. (2021). HOW TO GUIDE CHEMICAL ENGINEERING STUDENTS IN THE SOLUTION OF COMPLEX ENGINEERING PROBLEMS. IATED. 9442-9450. https://doi.org/10.21125/inted.2021.1977S9442945

Project-Based Learning as a Coordination Methodology between Subjects in a Chemical Engineering Degree

[EN] An important issue in any academic degree is to develop a high level of vertical/horizontal coordination between the different subjects taught along the four courses. This activity takes into account the coordination of the contents and methodologies that the teachers teach and the students acquire, the timing when the students learn them and the homework/exams that they do. As a result, both teachers and students gain an overall view of the degree and the teaching-learning process improves. According to this idea, the teachers of the Chemical Engineering degree at Campus of Alcoy are participating in an Educational Innovation and Improvement Project (EIIP) for applying the project-based learning methodology to the design of an adsorption system for the elimination of dyes in wastewater from the textile industry. This work is scheduled along the four courses and is distributed between some of the basic or specialized subjects that the students attend. The adsorption column design is partially solved in each subject and the results obtained in one subject are used in the following. As a result, the project is completed sequentially throughout the degree applying a methodology based on teamwork. This paper shows some of the activities proposed in different subjects, their timing and assessments during four courses. These activities include laboratory work for obtaining adsorption equilibrium and adsorption kinetics experimental data together with column dynamic performance. Other activities belong to the modelling and simulation domain for establishing the mathematical equations corresponding to the different phenomena linked to adsorption. Also there are activities focused on experimental data treatment for estimating the parameters characterizing the adsorption isotherms or mass transfer coefficients. Finally, other activities are devoted to the column design and control, cost estimation, and oral/writing communication of the work done by the students.This article has been supported by Universitat Politècnica de València, particularly by the Vice-rectorate for Digital Resources and Documentation (Vicerrectorado de Recursos Digitales y Documentación) and Vice-Rectorate for Studies, Quality and Accreditation (Vicerrectorado de Estudios, Calidad y Acreditación) under the Call for Learning + Teaching (Convocatoria A+D2019: Aprendizaje + Docencia. Proyectos de Innovación y Mejora Educativa) and Project Code: A157. The authors would like to acknowledge the support of the Institute of Educational Sciences (Instituto de Ciencias de la Educación), the Evaluation and Monitoring Commission for Educational Innovation and Improvement Projects (Comisión de Evaluación y Seguimiento de Proyectos de Innovación y Mejora Educativa (CESPIME) and Escuela Politécnica Superior de Alcoy.Carbonell Alcaina, C.; Cardona, SC.; Domínguez-Candela, I.; Fombuena, V.; López Pérez, MF.; Lora-García, J.; Sanchis, R. (2021). Project-Based Learning as a Coordination Methodology between Subjects in a Chemical Engineering Degree. INTED proceedings (Online). 5965-5974. https://doi.org/10.21125/inted.2021.1193S5965597

Light-responsive bent-core liquid crystals as candidates for energy conversion and storage

IDC would like to thank the Universitat Politècnica de València (UPV), for the FPI grant (PAID-2019-SP20190013), the Generalitat Valenciana (GVA) and the European Social Fund (ESF), for the FPI grant (ACIF/2020/233) and the mobility grant (CIBEFP/2021/53). NFKA would like to thank Universiti Teknologi MARA (UiTM) for sponsoring her academic sabbatical leave and allowing her to work on this project. AMF would like to thank the Carnegie Trust for the Universities of Scotland, for the Research Incentive Grant RIG008586, the Royal Society and Specac Ltd., for the Research Grant RGS\R1\201397, the Royal Society of Chemistry for the award of a mobility grant (M19- 0000), and the Scottish Government and the Royal Society of Edinburgh for the award of a SAPHIRE project. The authors from INMA greatly appreciate financial support from projects of the Spanish Government PGC2018-093761-B-C31 [MCIU/AEI/FEDER, UE] and the Gobierno de Aragón/FEDER (research group E47_20R). Thanks are given to the nuclear magnetic resonance, mass spectrometry, and thermal analysis services of the INMA (Univ. Zaragoza-CSIC)Peer reviewedPostprin

Analysis of energy consumption as a key factor in seawater desalination projects

[EN] A global scenario of increasing vulnerability of water resources in Spain makes it increasingly necessary to find alternative sources to meet demand and to encourage natural resources conservation. Among others, desalination of seawater and brackish waters It is one of the most developed options. The desalination capacity of Spain by using reverse osmosis membranes is higher than 3 hm3/day, which represents 2% of the supply in agriculture and 5% of domestic consumption. Its energy intensity that has been decreasing in recent years up to 2.5 kWh/m3 for seawater, makes the costs of the water produced are still high compared to conventional water supply. That is why desalination plants only operate at full capacity during periods of high drought despite the high investment made. In this paper a new energy approach of the desalination process is presented to show which variables affect energy consumption. In addition, different future actions are explored that will reduce this consumption even further to make desalination more economically viable as a new safe water resource securing the water supply at any time.[ES] La situación de vulnerabilidad creciente de los recursos hídricos en España hace que cada vez sea más necesaria la búsqueda de fuentes alternativas para satisfacer la demanda y favorecer la conservación de los medios naturales. Entre otras, la desalación de aguas marinas y salobres es una opción de las más desarrolladas. La capacidad desaladora de España mediante membranas de osmosis inversa supera los 3 hm3/dia lo que representa el 2% del suministro en agricultura y el 5% del consumo doméstico. Su intensidad energética que ha ido disminuyendo en los últimos años hasta 2.5 kWh/m3 para agua de mar, hace que los costes del agua producida sean todavía elevados en comparación con el agua potabilizada convencional. Por ello, las plantas desaladoras solo funcionan a pleno rendimiento en periodos de elevada sequía a pesar de la elevada inversión realizada. En este trabajo se aborda un nuevo análisis energético de la desalación de agua de mar para observar que variables afectan en mayor medida al consumo de energía. Además, se exploran diferentes acciones de futuro que permitirán reducir aún más dicho consumo para hacer más económicamente viable la desalación como una nueva fuente segura de agua que garantice el suministro en todo momento.Lora-García, J.; López Pérez, MF.; Cardona, SC.; Fombuena, V.; Carbonell Alcaina, C. (2020). Análisis del consumo energético como factor clave en proyectos de desalación de agua de mar. Asociación Española de Dirección e Ingeniería de Proyectos (AIEPRO). 991-1003. http://hdl.handle.net/10251/178934S991100