Multi-resonant scatterers in sonic crystals: Locally multi-resonant acoustic metamaterial

An acoustic metamaterial made of a two-dimensional (2D) periodic array of multi-resonant acoustic scatterers is analyzed both experimentally and theoretically. The building blocks consist of a combination of elastic beams of low-density polyethylene foam (LDPF) with cavities of known area. Elastic resonances of the beams and acoustic resonances of the cavities can be excited by sound producing several attenuation peaks in the low frequency range. Due to this behavior the periodic array with long wavelength multi-resonant structural units can be classified as a locally multi-resonant acoustic metamaterial (LMRAM) with strong dispersion of its effective properties. The results presented in this paper could be used to design effective tunable acoustic filters for the low frequency range. (C) 2012 Elsevier Ltd. All rights reserved.This work was supported by MCI Secretaria de Estado de Investigacion (Spanish government) and FEDER funds, under Grants MAT2009-09438 and MTM2009-14483-C02-02. V.R.G. is grateful for the support of "Programa de Contratos Post-Doctorales con Movilidad UPV (CEI-01-11)". A.K. and O.U. are grateful for the support of EPSRC (UK) through research Grant EP/E063136/1.Romero García, V.; Krynkin, A.; García-Raffi, LM.; Umnova, O.; Sánchez Pérez, JV. (2013). Multi-resonant scatterers in sonic crystals: Locally multi-resonant acoustic metamaterial. Journal of Sound and Vibration. 332(1):184-198. doi:10.1016/j.jsv.2012.08.003S184198332

The palaeoweatherings on the iberian hercynian basernent: approach to a regional interpretation from sorne spanish profiles

The Hercynian basement of the Iberian Peninsula has undergone different stages of supergenic weathering which has given rise to a superposition of several «weathering mantles». Remnants ofan old weathering mantle, Mesozoic in age, and related to a planation surface older than the Alpine tectonic phases, have been found. Nowadays the fragments of this old surface appear unleveled and/or fossilized by younger sediments. likewise, related to the «Raña» sediments ofUpper Neogene-lower Pleistocene age, appears a weathering mantle, probably active today, which is rich in kaolinite and with strong hydromorphic features

Deterioro de monumentos graníticos por cristalización de sales en ambiente urbano con baja contaminación

The effect of salt crystallization on granite (s.l) rocks used as building material in an urban environment with low atmospheric pollution was studied. The manners of salt crystallization and the subsequent deterioration caused were analyzed in unweathered granite and other fades which had undergone strong transformations in quarries before being used as stone materials, "alterites".Se estudia el efecto de la cristalización de sales solubles en rocas graníticas s.l empleadas como materiales de construcción, en ambiente urbano con baja contaminación atmosférica. Las formas en que cristalizan las sales y el deterioro asociado a su presencia son analizados en granitos sanos y en otras facies que han sufrido fuertes transformaciones en cantera previas a su empleo como materiales de construcción ("alteritas")

Zero-lag long-range synchronization via dynamical relaying

We show that simultaneous synchronization between two delay-coupled oscillators can be achieved by relaying the dynamics via a third mediating element, which surprisingly lags behind the synchronized outer elements. The zero-lag synchronization thus obtained is robust over a considerable parameter range. We substantiate our claims with experimental and numerical evidence of these synchronization solutions in a chain of three coupled semiconductor lasers with long inter-element coupling delays. The generality of the mechanism is validated in a neuronal model with the same coupling architecture. Thus, our results show that synchronized dynamical states can occur over long distances through relaying, without restriction by the amount of delay.Comment: 10 pages, 4 figure

On the uniformization of L-valued frames

This note discusses the appropriate way of uniformizing the notion of an L-valued frame introduced by A. Pultr and S. Rodabaugh in [Lattice-valued frames, functor categories, and classes of sober spaces, Chapter 6 of Topological and Algebraic Structures in Fuzzy Sets: A Handbook of Recent Developments in the Mathematics of Fuzzy Sets, Kluwer, 2003]. It covers the case of a completely distributive lattice L (which is, in a certain sense, the most general one) and studies the corresponding category of uniform L-valued frames

Comportamiento de barreras de cristales de sonido con dispersores resonantes

[EN] During the last few years there has been increasing interest in designing devices for controlling noise. In this work experimental data and numerical simulations are presented for the noise attenuation provided by Sonic Crystals (SC). The proposed SC is formed by elongated U-profile frames made of soft material. The single scatterer of that type may support resonances related to the material physical parameters and resonant cavity. The observed resonance effects give clear enhancement of the SC noise attenuation capability at the low frequency regime. Numerical simulations based on Finite Elements Method (FEM) show a good agreement with experimental results.[ES] En los últimos años ha habido un gran interés en el diseño de sistemas para el control de ruido. En este trabajo se muestran resultados experimentales y simulaciones numéricas para el estudio de las propiedades de atenuación de los Cristales de Sonido (CS). Se propone el uso de dispersores de baja densidad en forma de U que pueden soportar resonancias relacionadas con las propiedades físicas del material, así como resonancias debidas a la forma geométrica del dispersor. Las resonancias observadas en este trabajo, producen una mejora de las posibilidades de los Cristales de Sonido como barreras acústicas en el régimen de bajas frecuencias. Las simulaciones numéricas basadas en el Método de los Elementos Finitos (MEF) muestran una gran similitud con los resultados experimentales.Los autores agradecen la colaboración de la Dra. O. Umnova por sus comentarios constructivos del trabajo. V. Romero-García agradece a la University of Salford la oportunidad que le ha dado para desarrollar parte de este trabajo utilizando sus instalaciones. Este trabajo ha sido financiado por el Ministerio de Cultura y por los fondos FEDER, proyecto MAT2006-03097Romero García, V.; Krynkin, A.; García-Raffi, LM. (2010). Comportamiento de barreras de cristales de sonido con dispersores resonantes. Revista de Acústica. 41:5-11. http://hdl.handle.net/10251/624335114

Effect of dopants on the structure of titanium oxide used as a photocatalyst for the removal of emergent contaminants

Photocatalysts composed of titanium dioxide modified with B, F, N and P have been synthesized, characterized and applied to the degradation of caffeine, diclofenac, ibuprofen and salicylic acid. The modified TiO2 samples were prepared by the sol–gel technique starting from titanium(IV) isopropoxide and using H3BO3, NH4F, N(C2H5OH)3 and H3PO4 as precursors of the modifiers, with the content varying between 0 and 5 wt%. Structural characterization was based on nitrogen physisorption at −196 °C, powder X-ray diffraction (PXRD), simultaneous thermogravimetric/differential thermal analysis (TG/DTA) and X-ray photoelectron spectroscopy (XPS). The structural properties of the modified TiO2 solids were significantly different depending on the nature and amount of modifiers and the calcination temperature. TiO2 in the anatase phase was obtained in all cases and was stable upon calcination at 400 °C. The photocatalytic degradation of caffeine, diclofenac, ibuprofen and salicylic acid by modified TiO2 was investigated under ultraviolet irradiation at 25 °C. The photocatalytic degradation behavior followed the order: caffeine > diclofenac = ibuprofen > salicylic acid. B-doped TiO2 was the most efficient catalyst in the degradation of these selected emerging contaminants

Oral cyanocobalamin is effective in the treatment of vitamin B12 deficiency in crohn’s disease

Cobalamin deficiency is common in patients with Crohn’s disease (CD). Intramuscular cobalamin continues to be the standard therapy for the deficiency and maintenance treatment in these patients, although oral route has been demonstrated to be effective in other pathologies with impaired absorption. Our aims were to evaluate the efficacy of oral therapy in the treatment of cobalamin deficiency and in long-term maintenance in patients with Crohn’s disease. We performed a multicenter retrospective cohort study that included 94 patients with Crohn’s disease and cobalamin deficiency. Seventy-six patients had B12 deficiency and 94.7% of them normalized their cobalamin levels with oral treatment. The most used dose was 1 mg/day, but there were no significant differences in treatment effectiveness depending on the dose used (=1 mg/24 h vs. <1 mg/24 h). Eighty-two patients had previous documented B12 deficiency and were treated with oral B12 to maintain their correct cobalamin levels. After a mean follow-up of 3 years, the oral route was effective as maintenance treatment in 81.7% of patients. A lack of treatment adherence was admitted by 46.6% of patients in who the oral route failed. In conclusion, our study shows that oral cyanocobalamin provides effective acute and maintenance treatment for vitamin B12 deficiency caused by CD with or without ileum resection

Humic-like substances from urban waste as auxiliaries for photo-Fenton treatment: a fluorescence EEM-PARAFAC study

In this work, analysis of excitation-emission-matrices (EEM) has been employed to gain further insight into the characterization of humic like substances (HLS) obtained from urban wastes (soluble bio-organic substances, SBOs). In particular, complexation of these substances with iron and changes along a photo-Fenton process have been studied. Recorded EEMs were decomposed by using parallel factor analysis (PARAFAC). Three fluorescent components were identified by PARAFAC modeling of the entire set of SBO solutions studied. The EEM peak locations (λex/λem) of these components were 310?330 nm/400?420 nm (C1), 340?360 nm/450?500 nm (C2), and 285 nm/335?380 nm (C3). Slight variations of the maximum position of each component with the solution pH were observed. The interaction of SBO with Fe(III) was characterized by determining the stability constants of the components with Fe(III) at different pH values, which were in the order of magnitude of the ones reported for humic substances and reached their highest values at pH = 5. Photochemical experiments employing SBO and Fe(III), with and without H2O2, showed pH-dependent trends for the evolution of the modeled components, which exhibited a strong correlation with the efficiency reported for the photo-Fenton processes in the presence of SBO at different pH values.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicada