Control of multi-terminal HVDC networks towards wind power integration: A review

© 2015 Elsevier Ltd. More interconnections among countries and synchronous areas are foreseen in order to fulfil the EU 2050 target on the renewable generation share. One proposal to accomplish this challenging objective is the development of the so-called European SuperGrid. Multi-terminal HVDC networks are emerging as the most promising technologies to develop such a concept. Moreover, multi-terminal HVDC grids are based on highly controllable devices, which may allow not only transmitting power, but also supporting the AC grids to ensure a secure and stable operation. This paper aims to present an overview of different control schemes for multi-terminal HVDC grids, including the control of the power converters and the controls for power sharing and the provision of ancillary services. This paper also analyses the proposed modifications of the existing control schemes to manage high participation shares of wind power generation in multi-terminal grids.Postprint (author's final draft

Docència de la genètica

Màster Universitari de Formació del Professorat de Secundària Obligatòria i Batxillerat, Facultat d'Educació, Universitat de Barcelona. Curs: 2022-2023. Tutors: David Bueno i Torrens, Ferran Casals López[cat] La genètica forma part del currículum d’ESO i batxillerat de l’assignatura de biologia. La seva docència ha estat clàssicament qualificada com difícil per als estudiants i, malgrat la seva importància creixent, molts conceptes no són compresos per la societat. Aquest treball analitza diferents branques de la docència de la genètica com els canvis en les legislacions durant els darrers quinze anys, els llibres de text així com altres recursos. S’ha observat un clar continuisme en els currículums tant pel que fa a sabers com per les competències. En el cas dels sabers destaca la importància atribuïda a la genètica mendeliana. L’anàlisi dels llibres de text no ha estat concloent al no poder accedir als cursos on es desenvolupa el gruix de la genètica. La incorporació de la bioètica i de temes socials semblen una bona eina per a l’aprenentatge i motiven l’alumnat. La vinculació amb el món de la recerca també s’ha demostrat molt beneficiosa en l’aprenentatge de les ciències. Les propostes de millora es centren en posar la genètica molecular com a pilar de la docència de la genètica i motivar l’alumnat mitjançant temes socials i recerca. El professorat requereix més formació i s’ha de fer servir material adequat

Power system stabilizer control for wind power to enhance power system stability

The paper presents a small signal stability analysis for power systems with wind farm interaction. Power systems have damping oscillation modes that can be excited by disturbance or fault in the grid. The power converters of the wind farms can be used to reduce these oscillations and make the system more stable. These ideas are explored to design a power system stabilized (PSS) for a network with conventional generators and a wind farm in order to increase the damping of the oscillation modes. The proposed stabilizer is evaluated by simulation using DigSilent PowerFactoryPostprint (published version

Histone H1 Post-Translational Modifications : Update and Future Perspectives

Histone H1 is the most variable histone and its role at the epigenetic level is less characterized than that of core histones. In vertebrates, H1 is a multigene family, which can encode up to 11 subtypes. The H1 subtype composition is different among cell types during the cell cycle and differentiation. Mass spectrometry-based proteomics has added a new layer of complexity with the identification of a large number of post-translational modifications (PTMs) in H1. In this review, we summarize histone H1 PTMs from lower eukaryotes to humans, with a particular focus on mammalian PTMs. Special emphasis is made on PTMs, whose molecular function has been described. Post-translational modifications in H1 have been associated with the regulation of chromatin structure during the cell cycle as well as transcriptional activation, DNA damage response, and cellular differentiation. Additionally, PTMs in histone H1 that have been linked to diseases such as cancer, autoimmune disorders, and viral infection are examined. Future perspectives and challenges in the profiling of histone H1 PTMs are also discussed

Power system stabiliser capability of offshore wind power plants

Nowadays, wind power generation is being located offshore because of its higher wind speed at lower height and larger installation zones in comparison with onshore technologies. Recently, the concept of wind power plant has been introduced as a result of the increment of wind power penetration in power systems. Transmission system operators are requiring wind power generation to help to power system with some ancillary services such as fault ride through or power system stabiliser capability. Therefore, it is important to study power system stabiliser capability of wind power plants. In this paper, a comparison of various power system stabiliser schemes is presented. The effect of the distance from the shore tie-line to the offshore wind farm on the controller response is also evaluated. These studies show that offshore wind power plants have promising power system stabiliser capability even using local input signals.Postprint (published version

Enhanced Parallel Sine Cosine Algorithm for Constrained and Unconstrained Optimization

The sine cosine algorithm’s main idea is the sine and cosine-based vacillation outwards or towards the best solution. The first main contribution of this paper proposes an enhanced version of the SCA algorithm called as ESCA algorithm. The supremacy of the proposed algorithm over a set of state-of-the-art algorithms in terms of solution accuracy and convergence speed will be demonstrated by experimental tests. When these algorithms are transferred to the business sector, they must meet time requirements dependent on the industrial process. If these temporal requirements are not met, an efficient solution is to speed them up by designing parallel algorithms. The second major contribution of this work is the design of several parallel algorithms for efficiently exploiting current multicore processor architectures. First, one-level synchronous and asynchronous parallel ESCA algorithms are designed. They have two favors; retain the proposed algorithm’s behavior and provide excellent parallel performance by combining coarse-grained parallelism with fine-grained parallelism. Moreover, the parallel scalability of the proposed algorithms is further improved by employing a two-level parallel strategy. Indeed, the experimental results suggest that the one-level parallel ESCA algorithms reduce the computing time, on average, by 87.4% and 90.8%, respectively, using 12 physical processing cores. The two-level parallel algorithms provide extra reductions of the computing time by 91.4%, 93.1%, and 94.5% with 16, 20, and 24 processing cores, including physical and logical cores. Comparison analysis is carried out on 30 unconstrained benchmark functions and three challenging engineering design problems. The experimental outcomes show that the proposed ESCA algorithm behaves outstandingly well in terms of exploration and exploitation behaviors, local optima avoidance, and convergence speed toward the optimum. The overall performance of the proposed algorithm is statistically validated using three non-parametric statistical tests, namely Friedman, Friedman aligned, and Quade tests.This research was supported by the Spanish Ministry of Science, Innovation and Universities and the Research State Agency under Grant RTI2018-098156-B-C54 cofinanced by FEDER funds and the Ministry of Science and Innovation and the Research State Agency under Grant PID2020-120213RB-I00 cofinanced by FEDER funds

Effect of carrier transfer on the PL intensity in self-assembled In (Ga) As/GaAs quantum rings

We present results concerning the carrier transfer between In(Ga)As quantum rings in a stacked multilayer structure, which is characterised by a bimodal size distribution. This transfer of carriers explains the observed temperature behaviour of diode lasers based on that kind of stacked layer structures. The inter-ring carrier transfer can be possible by phonon assisted tunnelling from the ground state of the smallring family towards the big-ring family of the bimodal size distribution. This process is thermally activated in the range 40–80 K.This work was partially supported by Spanish MCyT Nanoself I and II projects TIC2002-04096-C03 and TEC2005-05781-C03-03, the SANDiE Network of excellence (Contract No. NMP4-CT-2004-500101) and the AECI Spain-Tunisia bilateral research action No. 2/04/R.Peer reviewe

Experiències senzilles de física recreativa com a recurs didàctic per a introduir i consolidar conceptes de física

En aquest projecte utilitzarem experiències senzilles de física recreativa per a introduir i consolidar conceptes de física general. Aquest recurs didàctic s’ha posat en marxa a la matèria de Complements per a la Formació Disciplinar en Física, corresponent al Màster Universitari en Formació del Professorat d’Educació Secundària, perquè molts estudiants no han cursat els estudis universitaris de Física. Amb la realització d’aquests experiments pretenem dotar al futur professorat de secundària d’una eina pedagògica que motive els estudiants cap a la física, fent que l’aprenentatge siga més significatiu i perdure en el temps. Per altra banda, es prestarà especial atenció a ressaltar la interdisciplinarietat de la física amb altres ciències i amb la vida quotidiana, ja que és un factor motivador que afavoreix l’aprenentatge. Durant la realització d’aquest projecte es dissenyarà i es posarà en marxa un recull d’experiències de diversos camps de la física. Cadascun dels experiments que es realitzaran, senzills i moltes vegades sorprenents, tindrà l’objectiu d’introduir i consolidar un concepte físic, a més de fomentar l’interès dels alumnes per la matèria de física

High-pressure theoretical and experimental study of HgWO4

This is an Author's Accepted Manuscript of an article published in Lopez-Solano, J.; Rodriguez-Hernandez, P.; Muñoz, A.; Santamaria-Perez, D. et al.(2011). High-pressure theoretical and experimental study of HgWO4. High Pressure Research. 31(1):58-63. doi:10.1080/08957959.2010.521735HgWO 4 at ambient pressure is characterized using a combination of ab initio calculations, X-ray diffraction and Raman scattering measurements. The effect of low pressure and temperature on the structural stability is analysed. Extending our ab initio study to the range of higher pressures, a sequence of stable phases up to 30GPa is proposed. © 2011 Taylor & Francis.We thank J.M. Menendez for his help in the use of the GIBBS code. This work has been supported by the Spanish MEC under Projects MAT2007-65990-C03-01/03, MAT2010-21270-C04-03/04 and CSD-2007-00045 and by the "Vicerrectorado de Innovacion y Desarrollo de la UPV" (PAID-05-2009 through project UPV2010-0096). We gratefully acknowledge computational time provided by the "Red Espanola de Supercomputacion" at the supercomputer "Atlante". S. R. acknowledges financial support from the "Vicerrectorado de Investigacion de la UPV" through grant PAID-02-09-3085.Lopez-Solano, J.; Rodriguez-Hernandez, P.; Muñoz, A.; Santamaria-Perez, D.; Manjón Herrera, FJ.; Ray, S.; Gomis Hilario, O.... (2011). High-pressure theoretical and experimental study of HgWO4. High Pressure Research. 31(1):58-63. https://doi.org/10.1080/08957959.2010.521735S5863311Manjón, F. J., & Errandonea, D. (2009). Pressure-induced structural phase transitions in materials and earth sciences. physica status solidi (b), 246(1), 9-31. doi:10.1002/pssb.200844238Errandonea, D., Manjón, F. J., Garro, N., Rodríguez-Hernández, P., Radescu, S., Mujica, A., … Tu, C. Y. (2008). Combined Raman scattering andab initioinvestigation of pressure-induced structural phase transitions in the scintillatorZnWO4. Physical Review B, 78(5). doi:10.1103/physrevb.78.054116Ruiz-Fuertes, J., López-Moreno, S., Errandonea, D., Pellicer-Porres, J., Lacomba-Perales, R., Segura, A., … González, J. (2010). High-pressure phase transitions and compressibility of wolframite-type tungstates. Journal of Applied Physics, 107(8), 083506. doi:10.1063/1.3380848Lacomba-Perales, R., Errandonea, D., Martinez-Garcia, D., Rodríguez-Hernández, P., Radescu, S., Mujica, A., … Polian, A. (2009). Phase transitions in wolframite-typeCdWO4at high pressure studied by Raman spectroscopy and density-functional theory. Physical Review B, 79(9). doi:10.1103/physrevb.79.094105Manjón, F. J., López-Solano, J., Ray, S., Gomis, O., Santamaría-Pérez, D., Mollar, M., … Muñoz, A. (2010). High-pressure structural and lattice dynamical study ofHgWO4. Physical Review B, 82(3). doi:10.1103/physrevb.82.035212Kresse, G., & Hafner, J. (1993). Ab initiomolecular dynamics for liquid metals. Physical Review B, 47(1), 558-561. doi:10.1103/physrevb.47.558Kresse, G., & Furthmüller, J. (1996). Efficient iterative schemes forab initiototal-energy calculations using a plane-wave basis set. Physical Review B, 54(16), 11169-11186. doi:10.1103/physrevb.54.11169Blöchl, P. E. (1994). Projector augmented-wave method. Physical Review B, 50(24), 17953-17979. doi:10.1103/physrevb.50.17953Perdew, J. P., Ruzsinszky, A., Csonka, G. I., Vydrov, O. A., Scuseria, G. E., Constantin, L. A., … Burke, K. (2008). Restoring the Density-Gradient Expansion for Exchange in Solids and Surfaces. Physical Review Letters, 100(13). doi:10.1103/physrevlett.100.136406Monkhorst, H. J., & Pack, J. D. (1976). Special points for Brillouin-zone integrations. Physical Review B, 13(12), 5188-5192. doi:10.1103/physrevb.13.5188Blanco, M. A., Francisco, E., & Luaña, V. (2004). GIBBS: isothermal-isobaric thermodynamics of solids from energy curves using a quasi-harmonic Debye model. Computer Physics Communications, 158(1), 57-72. doi:10.1016/j.comphy.2003.12.001Kresse, G., Furthmüller, J., & Hafner, J. (1995). Ab initioForce Constant Approach to Phonon Dispersion Relations of Diamond and Graphite. Europhysics Letters (EPL), 32(9), 729-734. doi:10.1209/0295-5075/32/9/005Wahl, R., Vogtenhuber, D., & Kresse, G. (2008). SrTiO3andBaTiO3revisited using the projector augmented wave method: Performance of hybrid and semilocal functionals. Physical Review B, 78(10). doi:10.1103/physrevb.78.104116Jeitschko, W., & Sleight, A. W. (1973). The crystal structure of HgMoO4 and related compounds. Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry, 29(4), 869-875. doi:10.1107/s056774087300347