المؤلفون: Derbal, Rachid, Benmansour, Nassima, Djafour, Mustapha, Matallah, Mohammed, Ivorra, Salvador

المساهمون: Universidad de Alicante. Departamento de Ingeniería Civil, Grupo de Ensayo, Simulación y Modelización de Estructuras (GRESMES)

مصطلحات موضوعية: Ground motion, Spatial variability, Simulation, Wave propagation, Coherency loss, Local geological site effect, Mecánica de Medios Continuos y Teoría de Estructuras

الوصف: The evaluation of the seismic hazard for a given site is to estimate the seismic ground motion at the surface. This is the result of the combination of the action of the seismic source, which generates seismic waves, the propagation of these waves between the source and the site, and site local conditions. The aim of this work is to evaluate the sensitivity of dynamic response of extended structures to spatial variable ground motions (SVGM). All factors of spatial variability of ground motion are considered, especially local site effect. In this paper, a method is presented to simulate spatially varying earthquake ground motions. The scheme for generating spatially varying ground motions is established for spatial locations on the ground surface with varying site conditions. In this proposed method, two steps are necessary. Firstly, the base rock motions are assumed to have the same intensity and are modelled with a filtered Tajimi-Kanai power spectral density function. An empirical coherency loss model is used to define spatial variable seismic ground motions at the base rock. In the second step, power spectral density function of ground motion on surface is derived by considering site amplification effect based on the one dimensional seismic wave propagation theory. Several dynamics analysis of a curved viaduct to various cases of spatially varying seismic ground motions are performed. For comparison, responses to uniform ground motion, to spatial ground motions without considering local site effect, to spatial ground motions with considering coherency loss, phase delay and local site effects are also calculated. The results showed that the generated seismic signals are strongly conditioned by the local site effect. In the same sense, the dynamic response of the viaduct is very sensitive of the variation of local geological conditions of the site. The effect of neglecting local site effect in dynamic analysis gives rise to a significant underestimation of the seismic demand of the structure.

العلاقة: https://doi.org/10.12989/eas.2019.17.6.557Test; Earthquakes and Structures. 2019, 17(6): 557-566. doi:10.12989/eas.2019.17.6.557; 2092-7614 (Print); 2092-7622 (Online); http://hdl.handle.net/10045/100757Test; A10228017

الإتاحة: https://doi.org/10.12989/eas.2019.17.6.557Test
http://hdl.handle.net/10045/100757Test

المؤلفون: Torres Romero, Jeniffer, Cardenas, William, Carbajo, Jesús, Segovia-Eulogio, Enrique-Gonzalo, Ramis-Soriano, Jaime

المساهمون: Universidad de Alicante. Departamento de Física, Ingeniería de Sistemas y Teoría de la Señal, Universidad de Alicante. Departamento de Ingeniería Civil, Universidad de Alicante. Instituto Universitario de Física Aplicada a las Ciencias y las Tecnologías, Acústica Aplicada, Grupo de Ensayo, Simulación y Modelización de Estructuras (GRESMES)

مصطلحات موضوعية: Beam, Modal shape, Modal analysis, MLS, Bending wave propagation velocity, Física Aplicada, Mecánica de Medios Continuos y Teoría de Estructuras

الوصف: In this paper an alternative procedure to vibro-acoustics study of beam-type structures is presented. With this procedure, it is possible to determine the resonant modes, the bending wave propagation velocity through the study of the radiated acoustic field and their temporal evolution in the frequency range selected. As regards the purely experimental aspect, it is worth noting that the exciter device is an actuator similar to is the one employed in distributed modes loudspeakers; the test signal used is a pseudo random sequence, in particular, an MLS (Maximum length Sequence), facilitates post processing. The study case was applied to two beam-type structures made of a sandstone material called Bateig. The experimental results of the modal response and the bending propagation velocity are compared with well-established analytical solution: Euler-Bernoulli and Timoshenko models, and numerical models: Finite Element Method-FEM, showing a good agreement.

العلاقة: https://doi.org/10.24425/122376Test; Archives of Acoustics. 2018, 43(2): 283-295. doi:10.24425/122376; 0137-5075 (Print); 2300-262X (Online); http://hdl.handle.net/10045/76543Test

الإتاحة: https://doi.org/10.24425/122376Test
http://hdl.handle.net/10045/76543Test

المؤلفون: Naserpour, Mahin, Zapata Rodríguez, Carlos Javier, Zakery, Abdolnaser, Miret, Juan Jose

المساهمون: Universidad de Alicante. Departamento de Óptica, Farmacología y Anatomía, Universidad de Alicante. Instituto Universitario de Física Aplicada a las Ciencias y las Tecnologías, Óptica y Ciencias de la Visión

مصطلحات موضوعية: Wave propagation, Invariant optical fields, Beam shaping, Óptica

الوصف: We propose a simple yet efficient method for generating in-plane hollow beams with a nearly full circular light shell without the contribution of backward propagating waves. The method relies on modulating the phase in the near field of a centrosymmetric optical wave front, such as that from a high-numerical-aperture focused wave field. We illustrate how beam acceleration may be carried out by using an ultranarrow non-flat meta-surface formed by engineered plasmonic nanoslits. A mirror-symmetric, with respect to the optical axis, circular caustic surface is numerically demonstrated that can be used as an optical bottle. ; This research was funded by the Spanish Ministry of Economy and Competitiveness under the Project TEC2013-50416-EXP. M. Naserpour acknowledges financial support from the Ministry of Science, Research and Technology of Iran.

العلاقة: http://dx.doi.org/10.1007/s00340-015-6164-3Test; info:eu-repo/grantAgreement/MINECO//TEC2013-50416-EXP; Applied Physics B. 2015, 120(3): 551-556. doi:10.1007/s00340-015-6164-3; 0946-2171 (Print); 1432-0649 (Online); http://hdl.handle.net/10045/48955Test

الإتاحة: https://doi.org/10.1007/s00340-015-6164-3Test
http://hdl.handle.net/10045/48955Test

المؤلفون: Zapata Rodríguez, Carlos Javier, Pastor Calle, David, Miret, Juan Jose

المساهمون: Universidad de Alicante. Departamento de Óptica, Farmacología y Anatomía, Óptica y Ciencias de la Visión

مصطلحات موضوعية: Wave propagation, Diffraction theory, Phase, Óptica

الوصف: We reexamine the Gouy phase in ballistic Airy beams (AiBs). A physical interpretation of our analysis is derived in terms of the local phase velocity and the Poynting vector streamlines. Recent experiments employing AiBs are consistent with our results. We provide an approach which potentially applies to any finite-energy paraxial wave field that lacks a beam axis. ; This research was funded by the Spanish Ministry of Economy and Competitiveness under the project TEC2009-11635.

العلاقة: http://dx.doi.org/10.1364/OE.20.023553Test; info:eu-repo/grantAgreement/MICINN//TEC2009-11635; Optics Express. 2012, 20(21): 23553-23558. doi:10.1364/OE.20.023553; http://hdl.handle.net/10045/33877Test

الإتاحة: https://doi.org/10.1364/OE.20.023553Test
http://hdl.handle.net/10045/33877Test

المؤلفون: Naserpour, Mahin, Zapata Rodríguez, Carlos Javier, Zakery, Abdolnaser, Miret, Juan Jose

المساهمون: Universidad de Alicante. Departamento de Óptica, Farmacología y Anatomía, Óptica y Ciencias de la Visión

مصطلحات موضوعية: Wave propagation, Invariant optical fields, Diffraction theory, Óptica

الوصف: Spatially accelerating beams are non-diffracting beams whose intensity is localized along curvilinear trajectories, also incomplete circular trajectories, before diffraction broadening governs their propagation. In this paper we report on numerical simulations showing the conversion of a high-numerical-aperture focused beam into a nonparaxial shape-preserving accelerating beam having a beam-width near the diffraction limit. Beam shaping is induced near the focal region by a diffractive optical element that consists of a non-planar subwavelength grating enabling a Bessel signature. ; This research was funded by the Spanish Ministry of Economy and Competitiveness under the project TEC2011-29120-C05-01. M. Naserpour acknowledges financial support from the Ministry of Science, Research and Technology of Iran.

العلاقة: http://dx.doi.org/10.1016/j.optcom.2014.08.024Test; info:eu-repo/grantAgreement/MICINN//TEC2011-29120-C05-01; Optics Communications. 2015, 334: 79-84. doi:10.1016/j.optcom.2014.08.024; 0030-4018 (Print); 1873-0310 (Online); http://hdl.handle.net/10045/57947Test

الإتاحة: https://doi.org/10.1016/j.optcom.2014.08.024Test
http://hdl.handle.net/10045/57947Test

المؤلفون: Zapata Rodríguez, Carlos Javier, Pastor Calle, David, Martínez Martínez, Luis Enrique, Caballero, María T., Miret, Juan Jose

المساهمون: Universidad de Alicante. Departamento de Óptica, Farmacología y Anatomía, Grupo de Óptica y Percepción Visual (GOPV), Óptica y Ciencias de la Visión

مصطلحات موضوعية: Subwavelength Structures, Wave Propagation, Surface Plasmons, Óptica

الوصف: We examined the optical properties of nanolayered metal-dielectric lattices. At subwavelength regimes, the periodic array of metallic nanofilms demonstrates nonlocality-induced double refraction, conventional positive and as well as negative. In particular, we report on energy-flow considerations concerning both refractive behaviors concurrently. Numerical simulations provide transmittance of individual beams in Ag-TiO2 metamaterials under different configurations. In regimes of the effective-medium theory predicting elliptic dispersion, negative refraction may be stronger than the expected positive refraction. ; This research was funded by the Spanish Ministry of Economy and Competitiveness (project TEC2011-29120-C05-01).

العلاقة: http://dx.doi.org/10.4028/www.scientific.net/AMM.472.729Test; info:eu-repo/grantAgreement/MICINN//TEC2011-29120-C05-01; Applied Mechanics and Materials. 2014, 472: 729-733. doi:10.4028/www.scientific.net/AMM.472.729; 1660-9336 (Print); 1662-7482 (Online); http://hdl.handle.net/10045/57945Test

الإتاحة: https://doi.org/10.4028/www.scientific.net/AMM.472.729Test
http://hdl.handle.net/10045/57945Test

المؤلفون: Zapata Rodríguez, Carlos Javier, Miret, Juan Jose, Sorní Laserna, Josep, Vuković, Slobodan

المساهمون: Universidad de Alicante. Departamento de Óptica, Farmacología y Anatomía, Óptica y Ciencias de la Visión

مصطلحات موضوعية: Birefringence, Electromagnetic wave propagation, Surface plasmons, Óptica

الوصف: We rigorously analyze the propagation of localized surface waves that takes place at the boundary between a semi-infinite layered metal-dielectric (MD) nanostructure cut normally to the layers and a isotropic medium. It is demonstrated that Dyakonov-like surface waves (also coined dyakonons) with hybrid polarization may propagate in a wide angular range. As a consequence, dyakonon-based wave-packets (DWPs) may feature sub-wavelength beamwidths. Due to the hyperbolic-dispersion regime in plasmonic crystals, supported DWPs are still in the canalization regime. The apparent quadratic beam spreading, however, is driven by dissipation effects in metal. ; This work was supported by the Spanish Ministry of Economy and Competitiveness under Project TEC2009-11635 and by the Qatar National Research Fund under Project NPRP 09-462-1-074.

العلاقة: http://dx.doi.org/10.1109/JSTQE.2012.2230153Test; info:eu-repo/grantAgreement/MICINN//TEC2009-11635; IEEE Journal of Selected Topics in Quantum Electronics. 2013, 19(3): 4601408. doi:10.1109/JSTQE.2012.2230153; 1077-260X (Print); 1558-4542 (Online); http://hdl.handle.net/10045/40357Test

الإتاحة: https://doi.org/10.1109/JSTQE.2012.2230153Test
http://hdl.handle.net/10045/40357Test