Application of Robust Model Predictive Control to a Renewable Hydrogen-based Microgrid

In order to cope with uncertainties present in the renewable energy generation, as well as in the demand consumer, we propose in this paper the formulation and comparison of three robust model predictive control techniques, i. i. e., multi-scenario, tree-based, and chance-constrained model predictive control, which are applied to a nonlinear plant-replacement model that corresponds to a real laboratory-scale plant located in the facilities of the University of Seville. Results show the effectiveness of these three techniques considering the stochastic nature, proper of these systems

Transverse Spin and Spin-Orbit Coupling in Silicon Waveguides

Evanescent and tightly confined propagating waves exhibit a remarkable transverse spin density since the longitudinal component of the electric field is not negligible. In this work, we obtain via numerical simulations the electric field components of the fundamental guided modes of two waveguides typically used in silicon photonics: the strip and the slot waveguide. We obtain the relation between transverse and longitudinal field components, the transverse spin densities and other important parameters, such as the longitudinal component of the so-called Belinfante s spin momentum density. By asymmetrically placing a circularly-polarized point-like dipole source in regions showing local circular polarization, the guided mode is excited unidirectionally via spin-orbit coupling. In contrast to metal plates supporting surface plasmons, the multimode behavior of silicon waveguides results in different spin-orbit coupling properties for each guided mode. Our results may find application in silicon photonic devices, integrated quantum optics and polarization manipulation at the nanoscale.This work was supported in part by the Secretaria de Estado de Investigacion, Desarrollo e Innovacion under Grant TEC2014-51902-C2-1-R and in part by the Valencian Conselleria d'Educacio, Cultura i Esport under Grant PROMETEOII/2014/034.Espinosa Soria, A.; Martínez Abietar, AJ. (2016). Transverse Spin and Spin-Orbit Coupling in Silicon Waveguides. IEEE Photonics Technology Letters. 28(14):1561-1564. https://doi.org/10.1109/LPT.2016.2553841S15611564281

On the Comparison of Stochastic Model Predictive Control Strategies Applied to a Hydrogen-based Microgrid

In this paper, a performance comparison among three well-known stochastic model predictive control approaches, namely, multi-scenario, tree-based, and chance-constrained model predictive control is presented. To this end, three predictive controllers have been designed and implemented in a real renewable-hydrogen-based microgrid. The experimental set-up includes a PEM electrolyzer, lead-acid batteries, and a PEM fuel cell as main equipment. The real experimental results show significant differences from the plant components, mainly in terms of use of energy, for each implemented technique. Effectiveness, performance, advantages, and disadvantages of these techniques are extensively discussed and analyzed to give some valid criteria when selecting an appropriate stochastic predictive controller.Ministerio de Economía y Competitividad DPI2013-46912-C2-1-RMinisterio de Economía y Competitividad DPI2013-482443-C2-1-

Relationship between roll-off occurrence and spatial distribution of dehydrated tissue during RF ablation with cooled electrodes

Purpose: To study the relationship between roll-off (sudden increase in impedance) and spatial distribution of dehydrated tissue during RF ablation using a cooled electrode (temperatures around 100°C). Methods: We used a double approach: (1) theoretical modelling based on the finite element method, and (2) 20 ablations using an experimental study on ex vivo excised bovine liver in which we measured impedance progress and temperature at three points close to the electrode surface: 0.5 (T1), 1.5 (T2) and 2.5 (T3) mm from the tip. T2 was located exactly at the centre of the 30 mm long electrode. Results: Temperatures at T1 and T3 quickly rose to 100°C (at ≈20 and 40 s, respectively), while at the rise at T2 was somewhat slower, stabilized around 50 s and reached a maximum value of 99°C at about 60 s. Impedance reached a minimum of 65 Ω (plateau), began increasing at 50 s and continued rising throughout the procedure, reaching a value equal to the initial value at 70 s. Likewise, computed impedance dropped to ≈73 Ω (plateau), began increasing at 50 s and reached an impedance value equal to the initial value at ≈78 s, which approximately coincided with the time when the entire zone surrounding the electrode was within the 100°C isotherm. Conclusion: There is a close relationship between the moment at which roll-off occurs and the time when the entire electrode is completely encircled by the dehydrated tissue. The mid-electrode zone is the last in which tissue desiccation occurs.This work received financial support from the Spanish Plan Nacional de I+D+I del Ministerio de Ciencia e Innovacion, grant no. TEC2008-01369/TEC and FEDER Project MTM2010-14909. The translation of this paper was funded by the Universitat Politecnica de Valencia, Spain. The authors alone are responsible for the content and writing of the paper.Trujillo Guillen, M.; Alba Martínez, J.; Berjano, E. (2012). Relationship between roll-off occurrence and spatial distribution of dehydrated tissue during RF ablation with cooled electrodes. International Journal of Hyperthermia. 28(1):62-68. https://doi.org/10.3109/02656736.2011.631076S6268281Poon, R. T.-P., Fan, S.-T., Tsang, F. H.-F., & Wong, J. (2002). Locoregional Therapies for Hepatocellular Carcinoma: A Critical Review From the Surgeon’s Perspective. Annals of Surgery, 235(4), 466-486. doi:10.1097/00000658-200204000-00004Solbiati, L., Livraghi, T., Goldberg, S. N., Ierace, T., Meloni, F., Dellanoce, M., … Gazelle, G. S. (2001). Percutaneous Radio-frequency Ablation of Hepatic Metastases from Colorectal Cancer: Long-term Results in 117 Patients. Radiology, 221(1), 159-166. doi:10.1148/radiol.2211001624Ahmed, M., Brace, C. L., Lee, F. T., & Goldberg, S. N. (2011). Principles of and Advances in Percutaneous Ablation. Radiology, 258(2), 351-369. doi:10.1148/radiol.10081634Pereira, P. L., Trübenbach, J., Schenk, M., Subke, J., Kroeber, S., Schaefer, I., … Claussen, C. D. (2004). Radiofrequency Ablation: In Vivo Comparison of Four Commercially Available Devices in Pig Livers. Radiology, 232(2), 482-490. doi:10.1148/radiol.2322030184Li, X., Zhang, L., Fan, W., Zhao, M., Wang, L., Tang, T., … Liu, Y. (2011). Comparison of microwave ablation and multipolar radiofrequency ablation, both using a pair of internally cooled interstitial applicators: Results inex vivoporcine livers. International Journal of Hyperthermia, 27(3), 240-248. doi:10.3109/02656736.2010.536967Burdío, F., Tobajas, P., Quesada-Diez, R., Berjano, E., Navarro, A., Poves, I., & Grande, L. (2011). Distant Infusion of Saline May Enlarge Coagulation Volume During Radiofrequency Ablation of Liver Tissue Using Cool-tip Electrodes Without Impairing Predictability. American Journal of Roentgenology, 196(6), W837-W843. doi:10.2214/ajr.10.5202Burdío, F., Navarro, A., Berjano, E. J., Burdío, J. M., Gonzalez, A., Güemes, A., … Grande, L. (2008). Radiofrequency hepatic ablation with internally cooled electrodes and hybrid applicators with distant saline infusion using an in vivo porcine model. European Journal of Surgical Oncology (EJSO), 34(7), 822-830. doi:10.1016/j.ejso.2007.09.029Burdío, F., Berjano, E. J., Navarro, A., Burdío, J. M., Güemes, A., Grande, L., … de Gregorio, M. A. (2007). RF tumor ablation with internally cooled electrodes and saline infusion: what is the optimal location of the saline infusion? BioMedical Engineering OnLine, 6(1), 30. doi:10.1186/1475-925x-6-30Haemmerich D, Mathematical modeling of impedance controlled radiofrequency tumor ablation and ex-vivo validation. Buenos Aires, Argentina: Proceedings of the 32nd Annual International Conference of the IEEE EMBS, 2010, pp. 1605–1608Arata, M. A., Nisenbaum, H. L., Clark, T. W. I., & Soulen, M. C. (2001). Percutaneous Radiofrequency Ablation of Liver Tumors with the LeVeen Probe: Is Roll-off Predictive of Response? Journal of Vascular and Interventional Radiology, 12(4), 455-458. doi:10.1016/s1051-0443(07)61884-3Haemmerich, D., Chachati, L., Wright, A. S., Mahvi, D. M., Lee, F. T., & Webster, J. G. (2003). Hepatic radiofrequency ablation with internally cooled probes: effect of coolant temperature on lesion size. IEEE Transactions on Biomedical Engineering, 50(4), 493-500. doi:10.1109/tbme.2003.809488McGahan, J. P., Loh, S., Boschini, F. J., Paoli, E. E., Brock, J. M., Monsky, W. L., & Li, C.-S. (2010). Maximizing Parameters for Tissue Ablation by Using an Internally Cooled Electrode. Radiology, 256(2), 397-405. doi:10.1148/radiol.09090662Berjano, E. J., Burdío, F., Navarro, A. C., Burdío, J. M., Güemes, A., Aldana, O., … Gregorio, M. A. de. (2006). Improved perfusion system for bipolar radiofrequency ablation of liver: preliminary findings from a computer modeling study. Physiological Measurement, 27(10), N55-N66. doi:10.1088/0967-3334/27/10/n03Pätz, T., Kröger, T., & Preusser, T. (2009). Simulation of Radiofrequency Ablation Including Water Evaporation. World Congress on Medical Physics and Biomedical Engineering, September 7 - 12, 2009, Munich, Germany, 1287-1290. doi:10.1007/978-3-642-03882-2_341Berjano, E. J. (2006). BioMedical Engineering OnLine, 5(1), 24. doi:10.1186/1475-925x-5-24Jo, B., & Aksan, A. (2010). Prediction of the extent of thermal damage in the cornea during conductive keratoplasty. Journal of Thermal Biology, 35(4), 167-174. doi:10.1016/j.jtherbio.2010.02.004Pearce, J., Panescu, D., & Thomsen, S. (2005). Simulation of diopter changes in radio frequency conductive keratoplasty in the cornea. Modelling in Medicine and Biology VI. doi:10.2495/bio050451Abraham, J. P., & Sparrow, E. M. (2007). A thermal-ablation bioheat model including liquid-to-vapor phase change, pressure- and necrosis-dependent perfusion, and moisture-dependent properties. International Journal of Heat and Mass Transfer, 50(13-14), 2537-2544. doi:10.1016/j.ijheatmasstransfer.2006.11.04

Assessment of Cold Ironing and LNG as Mitigation Tools of Short Sea Shipping Emissions in Port: A Spanish Case Study

[Abstract] By the end of 2025 European ports are required to provide (Directive 2014/94/EU) facilities to ensure the Liquefied Natural Gas (LNG) use and on-shore electricity supply for vessels (Cold Ironing—CI). Even though this involves considerable port investment, many uncertainties about CI and LNG performance exist because their application depends on vessel operators’ willingness. Additionally, lag times for CI connection/disconnection along with methane emissions from LNG undermine their feasibility for Short Sea Shipping (SSS). Since, among the SSS aims are the reduction in berthing times and its effectiveness for-inter-islands’ traffic where, land electricity grids are frequently dependent on the fuel burning generation by penalizing the CI performance. This paper introduces a calculation method to evaluate the pollution savings in monetary terms by CI and LNG use in SSS. The method is applied to three European routes by testing the environmental performance of two fleets: feeder and Ro-Pax vessels. The results show that feeders reach higher environmental improvements by using port mitigation than Ro-Pax vessels. Additionally, the need for ensuring the sustainability of on-shore grids before the CI implementation was evinced, especially in insularity frameworks, where the environmental benefits from LNG use proved to be more effectiveThis publication has been supported by the H2020 project FLOTANT, which is coordinated by the Oceanic Platform of the Canary Islands (PLOCAN). The project has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No. 81528

Exploiting metamaterials, plasmonics and nanoantennas concepts in silicon photonics

[EN] The interaction of light with subwavelength metallic nano-structures is at the heart of different current scientific hot topics, namely plasmonics, metamaterials and nanoantennas. Research in these disciplines during the last decade has given rise to new, powerful concepts providing an unprecedented degree of control over light manipulation at the nanoscale. However, only recently have these concepts been used to increase the capabilities of light processing in current photonic integrated circuits (PICs), which traditionally rely only on dielectric materials with element sizes larger than the light wavelength. Amongst the different PIC platforms, silicon photonics is expected to become mainstream, since manufacturing using well-established CMOS processes enables the mass production of low-cost PICs. In this review we discuss the benefits of introducing recent concepts arisen from the fields of metamaterials, plasmonics and nanoantennas into a silicon photonics integrated platform. We review existing works in this direction and discuss how this hybrid approach can lead to the improvement of current PICs enabling novel and disruptive applications in photonics.AM and AE-S acknowledge funding from contracts TEC2014-51902-C2-1-R and TEC2014-61906-EXP (MINECO/FEDER, UE) and, FR-F acknowledges funding from EPSRC (UK).Rodríguez Fortuño, FJ.; Espinosa-Soria, A.; Martínez Abietar, AJ. (2016). Exploiting metamaterials, plasmonics and nanoantennas concepts in silicon photonics. Journal of Optics. 18(12):123001-1-123001-14. https://doi.org/10.1088/2040-8978/18/12/123001S123001-1123001-14181

Europe's southernmost interglacial refugia as sentinels for the local extinction of mountain conifers

This research has been supported by a contract for University Teacher Training (Formación de Profesorado Universitario) (Ref. 18/03023) from the Spanish Ministry of Education, Culture and Sports (Ministerio de Educación, Cultura y Deportes del Gobierno de España), and research projects financed by the State Research Agency (SRA) and European Regional Development Fund (ERDF): PALEOPINSAPO (CSO2017-83576-P), MED-REFUGIA (RTI2018-101714-B-I00) and TED2021-132631B-I00; Andalusian Plan for Research, Development and Innovation: Oromed-Refugia (P18-RT- 4963); and ERDF Opera- tional Programme in Andalusia (EU regional programme): ForestMed (A-RNM-688-UGR20).The Serrania de Ronda is an exceptional palaeoecological laboratory for studying the dynamics of vegetation over time, due to its strategic geographical location at a biogeographical crossroads and its proven historical legacy. Many of the mountains that form part of this territory are today practically deforested, such as Sierra Blanca, whose geographic location at the heart of the Serranía de Ronda means that it has enormous potential as a bio- geographical crossroads: the occasional presence of Abies pinsapo, Pinus pinaster and Quercus rotundifolia suggests that it was once covered by a mixed forest of conifers and broad-leaved trees. The lack of environmental research in Sierra Blanca has facilitated the installation of large quarries, which have led to its exclusion from the Sierra de las Nieves National Park, which was created in 2021. We applied the pedoanthracological methodology, which has enabled us to discover paleo-populations of A. pinsapo and Pinus sylvestris-type. The results confirm that co- niferous forests previously covered a much wider area during the Holocene. These findings reinforce the role of Sierra Blanca as a high-altitude refuge for conifers during the warm stages of the Holocene and as a sentinel for the local extinction of mountain conifers. This information could help improve its management and conservation.Spanish Government 18/03023State Research Agency (SRA)European Commission CSO2017-83576-P, RTI2018-101714-B-I00, TED2021-132631B-I00Andalusian Plan for Research, Development and Innovation P18-RT-4963ERDF Operational Programme in Andalusia (EU regional programme) A-RNM-688-UGR2

On-Chip Optimal Stokes Nanopolarimetry Based on Spin-Orbit Interaction of Light

[EN] Full measurement of the polarization of light at the nanoscale is expected to be crucial in many scientific and technological disciplines. Ideally, such measurements will require miniaturized Stokes polarimeters able to determine polarization nondestructively, locally, and in real time. For maximum robustness in measurement, the polarimeters should also operate optimally. Recent approaches making use of plasmonic nanostructures or metasurfaces are not able to fulfill all these requirements simultaneously. Here, we propose and demonstrate a method for subwavelength-footprint Stokes nanopolarimetry based on spin-orbit interaction of light. The method, which basically consists on a subwavelength scatterer coupled to a (set of) multimode waveguide(s), can fully determine the state of polarization satisfying all the previous features. Remarkably, the nanopolarimetry technique can operate optimally (we design a nanopolarimeter whose polarization basis spans 99.7% of the maximum tetrahedron volume inside the Poincaré sphere) over a broad bandwidth. Although here experimentally demonstrated on a silicon chip at telecom wavelengths, spin-orbit interaction-based nanopolarimetry is a universal concept to be applied in any wavelength regime or technological platform.A.M. acknowledges support from the Spanish Ministry of Economy and Competiveness (MINECO) under grant TEC2014-51902-C2-1-R and the Valencian Conselleria d'Educacion, Cultura i Esport under grant PROMETEOII/2014/034. FJ.R.-F. acknowledges support from the European Research Council under project ERC-2016-STG-714151-PSINFONI. A.E.-S. acknowledges support from the Spanish Ministry of Economy and Competiveness (MINECO) under grant BES-2015-073146.Espinosa Soria, A.; Rodríguez Fortuño, FJ.; Griol Barres, A.; Martínez Abietar, AJ. (2017). On-Chip Optimal Stokes Nanopolarimetry Based on Spin-Orbit Interaction of Light. Nano Letters. 17(5):3139-3144. https://doi.org/10.1021/acs.nanolett.7b00564S3139314417

Método rápido de obtención de aceite de oliva virgen para determinación de acidez

A rapid and simple method to obtain, from olive samples, enough quantity of oil to determine acidity grade is proposed. From paste samples of milled olives, different fraction are separated to be centrifugated during 5 minutes at 4500 r.p.m. Oil acidity results obtained from sodium sulfate anhidrous and natural microtalc added samples are compared with blank samples, and with those obtained by the Abencor extraction procedure. The correlation between the acidity of oil samples obtained by the Abencor method is also analyzed against other samples obtained by the normalized method in Spain, norm UNE 55070, Soxhlet system. Results show that in all the centrifugated samples enough amount of oil is obtained to determin the acidity grade, it also show that treatment with sodium sulfate anhidrous obtains a bigger recovery percentage, and that in all 3 cases, the acidity shows a good correlation with that of the Abencor system, doubling the number of samples analysed by the Abencor system. It also shows that the acidity grade obtained by using the UNE 55070 norm is aproximately 0,3 grades above that obtained by the Abencor system.<br><br>Se propone un método rápido y sencillo para obtener, a partir de muestras de aceitunas, suficiente cantidad de aceite para determinar su grado de acidez. A partir de muestras de pasta de aceitunas molidas se separan distintas fracciones que se someten a un proceso de centrifugación a 4500 r.p.m. durante 5 minutos. Se comparan los resultados de acidez de los aceites obtenidos de las muestras con adición de microtalco natural y sulfato sódico anhidro, con muestras testigo, así como con el procedimiento de extracción Abencor. Se analiza también la correlación entre la acidez de muestras de aceite obtenidas por el método Abencor, con otras obtenidas por el método normalizado en España, norma UNE 55070, basado en la extracción del aceite por el método Soxhlet. Los resultados ponen de manifiesto que en las muestras centrifugadas se obtiene cantidad suficiente de aceite para la determinación del grado de acidez, que el tratamiento con sulfato sódico anhidro consigue mayor porcentaje de recuperación, y que, en los tres casos, la acidez presenta buena correlación con la del sistema Abencor, duplicando el número de muestras analizadas respecto a este método. Así mismo, se demuestra que el valor de acidez obtenido al aplicar la norma UNE 55070 es aproximadamente 0,3 grados por encima del obtenido por el sistema Abencor

Effect of Dietary Coenzyme Q10 Plus NADH Supplementation on Fatigue Perception and Health-Related Quality of Life in Individuals with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: A Prospective, Randomized, Double-Blind, Placebo-Controlled Trial

Coenzima Q10; Mitocondrias; Encefalomielitis miálgicaCoenzyme Q10; Mitochondria; Myalgic encephalomyelitisCoenzim Q10; Mitocondris; Encefalomielitis miàlgicaMyalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a complex, multisystem, and profoundly debilitating neuroimmune disease, probably of post-viral multifactorial etiology. Unfortunately, no accurate diagnostic or laboratory tests have been established, nor are any universally effective approved drugs currently available for its treatment. This study aimed to examine whether oral coenzyme Q10 and NADH (reduced form of nicotinamide adenine dinucleotide) co-supplementation could improve perceived fatigue, unrefreshing sleep, and health-related quality of life in ME/CFS patients. A 12-week prospective, randomized, double-blind, placebo-controlled trial was conducted in 207 patients with ME/CFS, who were randomly allocated to one of two groups to receive either 200 mg of CoQ10 and 20 mg of NADH (n = 104) or matching placebo (n = 103) once daily. Endpoints were simultaneously evaluated at baseline, and then reassessed at 4- and 8-week treatment visits and four weeks after treatment cessation, using validated patient-reported outcome measures. A significant reduction in cognitive fatigue perception and overall FIS-40 score (p < 0.001 and p = 0.022, respectively) and an improvement in HRQoL (health-related quality of life (SF-36)) (p < 0.05) from baseline were observed within the experimental group over time. Statistically significant differences were also shown for sleep duration at 4 weeks and habitual sleep efficiency at 8 weeks in follow-up visits from baseline within the experimental group (p = 0.018 and p = 0.038, respectively). Overall, these findings support the use of CoQ10 plus NADH supplementation as a potentially safe therapeutic option for reducing perceived cognitive fatigue and improving the health-related quality of life in ME/CFS patients. Future interventions are needed to corroborate these clinical benefits and also explore the underlying pathomechanisms of CoQ10 and NADH administration in ME/CFS.J.C.-M. received financial support and honoraria from Vitae Health Innovation Co., S.L. (Montmeló, Barcelona, Spain). This study was partially supported by the Vall d’Hebron Hospital Research Institute (Barcelona, Spain). Vitae Health Innovation Co. supplied both treatments (Coenzyme Q10 and NADH supplement tablets and placebo)