Monte Carlo simulation of damage and amorphization induced by swift-ion irradiation in LiNbO3

This paper presents a Monte Carlo (MC) simulation tool which is applied to describe the ion beam induced damage generated by electronic excitation in LiNbO3. Based on a previously published thermal spike based analytical model, the MC technique allows for a more flexible and accurate treatment of the problem. A main advantage of this approach with respect to the analytical one is the possibility of studying the role of statistical fluctuations, relevant at low fluences. The paper recalls the main features of the physical model, describes the MC algorithm, and compares simulation results to experimental data (irradiations of LiNbO3 using silicon ions at 5 and 7.5 MeV and oxygen ions at 5 MeV). © 2006 American Institute of Physics.Peer Reviewe

Monte Carlo simulation of damage and amorphization induced by swift-ion irradiation in LiNbO3

This paper presents a Monte Carlo (MC) simulation tool which is applied to describe the ion beam induced damage generated by electronic excitation in LiNbO3. Based on a previously published thermal spike based analytical model, the MC technique allows for a more flexible and accurate treatment of the problem. A main advantage of this approach with respect to the analytical one is the possibility of studying the role of statistical fluctuations, relevant at low fluences. The paper recalls the main features of the physical model, describes the MC algorithm, and compares simulation results to experimental data (irradiations of LiNbO3 using silicon ions at 5 and 7.5 MeV and oxygen ions at 5 MeV). © 2006 American Institute of Physics.Peer Reviewe

Characterisation and impact of non-uniformity on multi-junction solar cells (MJSC) caused by concentrator optics

In this work, it has been developed a method to generate non-homogeneous light patterns on multi-junction solar cells. These patterns have been generated modifying the distance between the CPV receiver and the primary optics, which is based on a Fresnel lens. In order to diminish the impact of other variables, the incident spectrum, laboratory temperature and effective concentration have been kept constant: SMRtop-mid = 1 ± 0.02, 25 ± 0.5ºC and 380 ± 3 suns, respectively. The light patterns on the top and middle subcells are measured using a CCD camera and band-pass filters. Results show that the electrical performance of the solar cells depends on the spatial and spectral profiles. The present work introduces a procedure to characterise and evaluate the impact of non-uniformities on the output of multi-junction solar cells. Nevertheless, this work is not intended to predict the actual output of the cell as a function of the light profiles, but to provide indications for possible underlying mechanisms.This work is partially funded by European Regional Development Fund (ERDF) and Spanish Economy Ministry, grant number ENE2016-78251-

Determinación de la composición química de piezas metálicas históricas: aplicación a un bronce romano

La deicrniinación de la composición química media de un bronce arqueoló gico no siempre es fácil. Algunos problemas a resolver son la heterogeneidad de la composición química, la dificultad de extracción de muestras o la importan cia de los elementos traza. En la comunicación se discute en primer lugar la me todología y técnicas de análisis apropiadas para la determinación de la compo sición de bronces singulares. Por último, se describe un procedimiento de obtención de viruta, cuasi no destructivo, para realizar análisis por procedimientos con vencionales. La validez y el significado de los resultados se discuten mediante la aplicación del procedimiento a un bronce de origen romano: el Hypnos ha llado en la villa romana de El Ruedo, en Almedinilla (Córdoba)

Generation of high-confinement step-like optical waveguides in LiNbO3 by swift heavy ion-beam irradiation

3 pages, 4 figures, 1 table.We demonstrate a swift ion-beam irradiation procedure based on electronic (not nuclear) excitation to generate a large index jump step-like optical waveguide (Δn0 ≈ 0.2, Δne ≈ 0.1) in LiNbO3. The method uses medium-mass ions with a kinetic energy high enough to assure that their electronic stopping power Se(z) reaches a maximum value close to the amorphous (latent) track threshold inside the crystal. Fluorine ions of 20 and 22 MeV and fluences in the range (1–30)×1014 are used for this work. A buried amorphous layer having a low refractive index (2.10 at a wavelength of 633 nm) is then generated at a controlled depth in LiNbO3, whose thickness is also tuned by irradiation fluence. The layer left at the surface remains crystalline and constitutes the core of the optical waveguide which, moreover, is several microns far from the end of the ion range. The waveguides show, after annealing at 300 °C, low propagation losses ( ≈ 1 dB/cm) and a high second-harmonic generation coefficient (50%–80% of that for bulk unirradiated LiNbO3, depending on the fluence). The formation and structure of the amorphous layer has been monitored by additional Rutherford backscattering/channeling experiments.We acknowledge the funding of the project MAT2002– 03220 (MEC). A. García-Navarro acknowledges the financial support of the MEC through a FPU Fellowship and of the Madrid City Hall-Residencia de Estudiantes.Peer reviewe

Process design for the manufacturing of soft X-ray gratings in single-crystal diamond by high-energy heavy-ion irradiation

Artículo con 9 figurasThis paper describes in detail a novel manufacturing process for optical gratings suitable for use in the UV and soft X-ray regimes in a single-crystal diamond substrate based on highly focused swift heavy-ion irradiation. This type of grating is extensively used in light source facilities such as synchrotrons or free electron lasers, with ever-increasing demands in terms of thermal loads, depending on beamline operational parameters and architecture. The process proposed in this paper may be a future alternative to current manufacturing techniques, providing the advantage of being applicable to single-crystal diamond substrates, with their unique properties in terms of heat conductivity and radiation hardness. The paper summarizes the physical principle used for the grating patterns produced by swift heavy-ion irradiation and provides full details for the manufacturing process for a specific grating configuration, inspired in one of the beamlines at the ALBA synchrotron light source, while stressing the most challenging points for a potential implementation. Preliminary proof-of-concept experimental results are presented, showing the practical implementation of the methodology proposed herein.The authors acknowledge funding support by the following projects: PID2020-112770RB-C22 from the Spanish Ministry of Science and Innovation, TechnoFusión (III)-CM (S2018/EMT-4437) from Comunidad de Madrid (cofinanced by ERDF and ESF), agreement between Community of Madrid and Universidad Autónoma de Madrid (item “Excellence of University Professorate”). M.L.C. acknowledges financial support from the research project “Captacion de Talento UAM” Ref: #541D300 supervised by the Vice-Chancellor of Research of Universidad Autónoma de Madrid (UAM). LOREA beamline at ALBA is a project co-funded by the European Regional Development Fund (ERDF) within the Framework of the Smart Growth Operative Programme 2014-2020. The authors acknowledge the support from The Centro de Microanálisis de Materiales (CMAM)—Universidad Autónoma de Madrid, for the beam time proposal (demonstration of a grating profile for soft X-rays in diamond via ion lithography) with code IuB-005/21, and its technical staff for their contribution to the operation of the accelerator. We also acknowledge P. Olivero for very useful comments on the manuscript draf

Effect of an organotin catalyst on the physicochemical properties and biocompatibility of castor oil-based polyurethane/cellulose composites

[EN] Polyurethane/cellulose composites were synthesized from castor-oil-derived polyols and isophorone diisocyanate using dibutyltin dilaurate (DBTDL) as the catalyst. Materials were obtained by adding 2% cellulose in the form of either microcrystals (20 lm) or nanocrystals obtained by acid hydrolysis. The aim was to assess the effects of filler particle size and the use of a catalyst on the physicochemical properties and biological response of these composites. The addition of the catalyst was found to be essential to prevent filler aggregations and to enhance the tensile strength and elongation at break. The cellulose particle size influenced the composite properties, as its nanocrystals heighten hydrogen bond interactions between the filler surface and polyurethane domains, improving resistance to hydrolytic degradation. All hybrids retained cell viability, and the addition of DBTDL did not impair their biocompatibility. The samples were prone to calcification, which suggests that they could find application in the development of bioactive materials.Universidad de La Sabana supported this work under Grant No. ING-176-2016. S.V.V. acknowledges the Universidad de La Sabana for the Teaching Assistant Scholarship for his master's studies. J.A.G.T. and A.V.L. acknowledge the support of the Spanish Ministry of Economy and Competitiveness (MINECO) through project DPI2015-65401-C3-2-R (including FEDER financial support). The authors acknowledge the assistance and advice of the Electron Microscopy Service of the UPV. CIBER-BBN is an initiative funded by the VI National R&D&I Plan 2008-2011, Iniciativa Ingenio 2010, Consolider Program. CIBER Actions are financed by the Instituto de Salud Carlos III with assistance from the European Regional Development Fund.Villegas-Villalobos, S.; Diaz, L.; Vilariño, G.; Vallés Lluch, A.; Gómez-Tejedor, J.; Valero, M. (2018). Effect of an organotin catalyst on the physicochemical properties and biocompatibility of castor oil-based polyurethane/cellulose composites. Journal of Materials Research. 33(17):2598-2611. https://doi.org/10.1557/jmr.2018.286S259826113317Capadona, J. R., Van Den Berg, O., Capadona, L. A., Schroeter, M., Rowan, S. J., Tyler, D. J., & Weder, C. (2007). A versatile approach for the processing of polymer nanocomposites with self-assembled nanofibre templates. Nature Nanotechnology, 2(12), 765-769. doi:10.1038/nnano.2007.379Kaushik, A., & Garg, A. (2013). Castor Oil Based Polyurethane Nanocomposites with Cellulose Nanocrystallites Fillers. Advanced Materials Research, 856, 309-313. doi:10.4028/www.scientific.net/amr.856.309Yilgör, I., Yilgör, E., & Wilkes, G. L. (2015). Critical parameters in designing segmented polyurethanes and their effect on morphology and properties: A comprehensive review. Polymer, 58, A1-A36. doi:10.1016/j.polymer.2014.12.014Javni, I., Petrovi?, Z. 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Industrial Crops and Products, 107, 378-385. doi:10.1016/j.indcrop.2017.05.041Yakovlev, Y. V., Gagolkina, Z. O., Lobko, E. V., Khalakhan, I., & Klepko, V. V. (2017). The effect of catalyst addition on the structure, electrical and mechanical properties of the cross-linked polyurethane/carbon nanotube composites. Composites Science and Technology, 144, 208-214. doi:10.1016/j.compscitech.2017.03.034Tang, Z. G., Teoh, S. H., McFarlane, W., Poole-Warren, L. A., & Umezu, M. (2002). In vitro calcification of UHMWPE/PU composite membrane. Materials Science and Engineering: C, 20(1-2), 149-152. doi:10.1016/s0928-4931(02)00025-5Dave, V. J., & Patel, H. S. (2017). Synthesis and characterization of interpenetrating polymer networks from transesterified castor oil based polyurethane and polystyrene. Journal of Saudi Chemical Society, 21(1), 18-24. doi:10.1016/j.jscs.2013.08.001Lundin, J. G., Daniels, G. C., McGann, C. L., Stanbro, J., Watters, C., Stockelman, M., & Wynne, J. H. (2016). Multi-Functional Polyurethane Hydrogel Foams with Tunable Mechanical Properties for Wound Dressing Applications. Macromolecular Materials and Engineering, 302(3), 1600375. doi:10.1002/mame.201600375Oprea, S., Joga, A., Zorlescu, B., & Oprea, V. (2014). Effect of the hard segment structure on properties of resorcinol derivatives-based polyurethane elastomers. High Performance Polymers, 26(8), 859-866. doi:10.1177/0954008314533359Kumar, M. N. S., & Siddaramaiah. (2007). Thermo gravimetric analysis and morphological behavior of castor oil based polyurethane-polyester nonwoven fabric composites. Journal of Applied Polymer Science, 106(5), 3521-3528. doi:10.1002/app.26826Datta, J., & Głowińska, E. (2014). Effect of hydroxylated soybean oil and bio-based propanediol on the structure and thermal properties of synthesized bio-polyurethanes. Industrial Crops and Products, 61, 84-91. doi:10.1016/j.indcrop.2014.06.050Conejero-García, Á., Gimeno, H. R., Sáez, Y. M., Vilariño-Feltrer, G., Ortuño-Lizarán, I., & Vallés-Lluch, A. (2017). Correlating synthesis parameters with physicochemical properties of poly(glycerol sebacate). European Polymer Journal, 87, 406-419. doi:10.1016/j.eurpolymj.2017.01.001Fang, W., Arola, S., Malho, J.-M., Kontturi, E., Linder, M. B., & Laaksonen, P. (2016). Noncovalent Dispersion and Functionalization of Cellulose Nanocrystals with Proteins and Polysaccharides. Biomacromolecules, 17(4), 1458-1465. doi:10.1021/acs.biomac.6b00067Rudnik, E., Resiak, I., & Wojciechowski, C. (1998). Thermoanalytical investigations of polyurethanes for medical purposes. Thermochimica Acta, 320(1-2), 285-289. doi:10.1016/s0040-6031(98)00485-7Lundin, J. G., McGann, C. L., Daniels, G. C., Streifel, B. C., & Wynne, J. H. (2017). Hemostatic kaolin-polyurethane foam composites for multifunctional wound dressing applications. Materials Science and Engineering: C, 79, 702-709. doi:10.1016/j.msec.2017.05.084Meskinfam, M., Bertoldi, S., Albanese, N., Cerri, A., Tanzi, M. C., Imani, R., … Farè, S. (2018). Polyurethane foam/nano hydroxyapatite composite as a suitable scaffold for bone tissue regeneration. Materials Science and Engineering: C, 82, 130-140. doi:10.1016/j.msec.2017.08.064Narine, S. S., Kong, X., Bouzidi, L., & Sporns, P. (2006). Physical Properties of Polyurethanes Produced from Polyols from Seed Oils: I. Elastomers. Journal of the American Oil Chemists’ Society, 84(1), 55-63. doi:10.1007/s11746-006-1006-4Alagi, P., Choi, Y. J., Seog, J., & Hong, S. C. (2016). Efficient and quantitative chemical transformation of vegetable oils to polyols through a thiol-ene reaction for thermoplastic polyurethanes. Industrial Crops and Products, 87, 78-88. doi:10.1016/j.indcrop.2016.04.027Benhamou, K., Kaddami, H., Magnin, A., Dufresne, A., & Ahmad, A. (2015). 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Castor oil-based polyurethanes containing cellulose nanocrystals. Polymer Engineering & Science, 51(7), 1389-1396. doi:10.1002/pen.21939Gao, Z., Peng, J., Zhong, T., Sun, J., Wang, X., & Yue, C. (2012). Biocompatible elastomer of waterborne polyurethane based on castor oil and polyethylene glycol with cellulose nanocrystals. Carbohydrate Polymers, 87(3), 2068-2075. doi:10.1016/j.carbpol.2011.10.027Cherian, B. M., Leão, A. L., de Souza, S. F., Costa, L. M. M., de Olyveira, G. M., Kottaisamy, M., … Thomas, S. (2011). Cellulose nanocomposites with nanofibres isolated from pineapple leaf fibers for medical applications. Carbohydrate Polymers, 86(4), 1790-1798. doi:10.1016/j.carbpol.2011.07.009Rocco, K. A., Maxfield, M. W., Best, C. A., Dean, E. W., & Breuer, C. K. (2014). In Vivo Applications of Electrospun Tissue-Engineered Vascular Grafts: A Review. Tissue Engineering Part B: Reviews, 20(6), 628-640. doi:10.1089/ten.teb.2014.0123Hocker, S. J. A., Hudson-Smith, N. V., Smith, P. 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La Acción Tutorial en la Facultad de Económicas: perspectivas presentes y futuras

El Programa de Acción Tutorial de Económicas, conocido coloquialmente como PATEC, cumple su novena edición en el presente curso académico 2013-2014. Desde sus inicios el PATEC se ha adaptado a las distintas titulaciones adscritas al Centro gracias a su gran flexibilidad, aspecto fundamental si tenemos en cuenta el tamaño y la heterogeneidad de nuestro Centro y las diferentes características de nuestros estudiantes. El objetivo de esta comunicación es dar a conocer el PATEC, sus objetivos, características y datos más relevantes, así como analizar su evolución lo que nos permitirá obtener una radiografía completa del Programa. Teniendo en cuenta las dificultades encontradas en la implementación del Programa en sus distintas ediciones trataremos de abordar planteamientos alternativos entre los que se encuentra la creación de una Red de Tutores que persigue optimizar la labor tutorial y facilitar el trabajo de futuros tutores. Asimismo, se expondrán diferentes experiencias innovadoras llevadas a cabo con el objetivo de incrementar la participación del alumnado

The TechnoFusion Consortium of Spanish institutions and facilities towards the development of fusion materials and related technologies in Europe

14 pags., 10 figs.With the objective of contributing to the European development of materials, technologies and facilities for the demonstration of the thermonuclear fusion, the construction of the unique TechnoFusión facility was planned in 2009. The TechnoFusión consortium, formed by selected Spanish research groups and laboratories located in Madrid, has jointly advanced in the search for solutions to the remaining technological issues of nuclear fusion by magnetic and inertial confinement. In addition, the foundation of the TechnoFusión partnership has been essential to create a network of collaborations, and also to expand and specialize human resources, by training scientists and technical staff in the use of high-tech tools. Supported by the TechnoFusión_Comunidad Madrid (III) regional programme, the consortium is focused on providing support for the construction of medium-­sized, relevant facilities in Madrid (Spain). Regarding magnetic and inertial fusion issues, the programme is structured in several key experiments and infrastructures, which combine the development of materials, of cutting-edge technologies and the construction of associated facilities, with the progress in simulation and application of computational neutronics:The authors acknowledge the funding by Community of Madrid, co-financed with Structural Funds (ERDF and ESF)), through the TechnoFusión (III)-CM (S2018/EMT-4437) programme. This work has also been carried out within the framework of the EUROfusion Consortium and has received funding from the European Union's Horizon 2020 research and innovation program under grant agreement number 633053. The views and opinions expressed in this document do not necessarily reflect those of the European Commission. In particular, R. González-Arrabal acknowledges the Convenio Plurianual con la Universidad Politécnica de Madrid en la línea de actuación Programa de Excelencia para el Profesorado Universitario of the CAM (Comunidad Autónoma Madrid)