Artículos (Física Aplicada I)

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Further insight in the high selectivity of Pb2+ removal over Cd2 in natural and dealuminated rich-clinoptilolite
(MDPI, 2025-04-27) Durán Avendaño, Yaneth Stephanie; Cruz Hernández, Norge; Ruiz Salvador, Ángel Rabdel; Abatal, Mohamed; Universidad de Sevilla. Departamento de Física Aplicada I; Universidad de Sevilla; Consejo Nacional de Humanidades, Ciencia y Tecnología (CONAHCyT). México; Universidad de Sevilla. FQM401: Simulación y Aplicación de Materiales
This research aims to understand the experimental results on the high selectivity of Pb2+ removal over Cd2+ in natural and dealuminated rich-clinoptilolite. For this purpose, we have considered the results of experimental and Density Functional Theory (DFT)-based simulated annealing (SA) on sorption of Pb2+ and Cd2+ from aqueous solution. The dealumination process of natural clinoptilolite (Nat-CLI) was done by H2SO4 solutions at different concentrations (0.1–1.0 M). The results show that the maximum sorption capacity (q,max) of Pb2+ and Cd2+ varied from 224.554 × 10−3 to 53.827 × 10−3 meq/g, and between 39.044 × 10−3 to 20.529 × 10−3 meq/g, respectively, when the values of Si/Al ratio change from 4.36 to 9.50. From a theoretical point of view, the global minimum energies of natural and dealuminated clinoptilolites before and after sorption of Pb2+ and Cd2+ were calculated by an SA method, where heating-cooling cycles were modeled by ab initio Molecular Dynamics followed by energy minimization. The theoretical results confirmed that for all Si/Al ratios, the sorption of Pb2+ and Cd2+ takes place, and for dealuminated systems, the exchange energy outcomes are more favorable for the Pb2+ cations. Since such energy differences are very small, it is not explained from a thermodynamic point of view. On the other hand, it could be understood from a kinetic perspective. In this way, we set that the atomic structural properties of the zeolite modify the first hydration coordination sphere of metal cations.
Ion Mobility and Segregation in Seed Surfaces Subjected to Cold Plasma Treatments
(American Chemical Society, 2025-02-24) Perea Brenes, Álvaro; Ruiz Pino, Natalia; Yubero, Francisco; Garcia, José Luis; Rodríguez González-Elipe, Agustín; Gómez Ramírez, Ana María; Prados Montaño, Antonio; López Santos, Carmen; Universidad de Sevilla. Departamento de Física Atómica, Molecular y Nuclear; Universidad de Sevilla. Departamento de Física Aplicada I; Ministerio de Ciencia e Innovación (MICIN). España; Agencia Estatal de Investigación. España; European Union (UE); Universidad de Sevilla; Junta de Andalucía
Plasma treatment of seeds is an efficient procedure to accelerate germination, to improve initial stages of plant growth, and for protection against pathogen infection. Most studies relate these beneficial effects with biochemical modifications affecting the metabolism and genetic growth factors of seeds and young plants. Using barley seeds, in this work, we investigate the redistribution of ions in the seed surface upon their treatment with cold air plasmas. In addition, we investigate the effect of plasma in the lixiviation of ions through the seeds’ hull when they are immersed in water. Ion redistribution in the outer layers of air plasmatreated seeds has been experimentally determined through X-ray photoelectron spectroscopy analysis in combination with in-depth chemical profiling with gas cluster ion beams. The results show that in the shallowest layers of the seed hull (at least up to a depth of ∼100 nm) there is an enrichment of K+ and Ca2+ ions, in addition to changes in the O/C and N/C atomic ratios. These data have been confirmed by the electron microscopy/fluorescence analysis of seed cuts. Observations have been accounted for by a Monte Carlo model, simulating the electrostatic interactions that develop between the negative charge accumulated at the seed surface due to the interaction with the plasma sheath and the positive ions existing in the interior. Furthermore, it is shown that upon water immersion of plasma-treated seeds mobilized ions tend to lixiviate more efficiently than in pristine seeds. The detection of a significant concentration of NO3− anions in the water has been attributed to a secondary reaction of nitrogen species incorporated into the seeds during plasma exposure with reactive oxygen species formed on their surface during this treatment. The implications of these findings for the improvement of the germination capacity of seeds are discussed.
Characterization and Suppression of Transmission Dips in Glide-Symmetric Holey Gap Waveguides
(Institute of Electrical and Electronics Engineers, 2025-06-03) Chen, Mingzheng; Bellbrant, Johan; Zetterstrom, Oskar; Mesa Ledesma, Francisco Luis; Quevedo Teruel, Óscar; Universidad de Sevilla. Departamento de Física Aplicada I; Ministerio de Ciencia, Innovación y Universidades (MICIU). España; European Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER); Universidad de Sevilla. TIC112: Microondas
The spurious transmission dips that occur in glide-symmetric holey gap waveguides (GSHGWs) are systematically characterized in this work, and the obtained information is used to suppress them in the intended operating band of the gap waveguide. The analysis relies on the dispersion characteristics of the waveguide segment with electromagnetic bandgap (EBG) holes. These characteristics are explored through the multimodal transfer matrix approach, particularly focusing on identifying relevant edge and waveguide modes. We find four types of unwanted dips in the transmission coefficient within the intended operation frequency band of the gap waveguide under study. The first three types are all associated with the edge mode mostly concentrated in the small air-gap region between the waveguide and the EBG holes, whereas the fourth type is caused by a narrow stopband in the waveguide mode. Based on a thorough understanding of all dips, we propose three viable solutions: placing EBG holes away from the waveguide channel, intersecting EBG holes with the waveguide channel, and intersecting additional small holes with the waveguide channel and the EBG holes. After comparison, the last solution with two small holes per EBG hole along the waveguide channel was demonstrated to be the most advantageous in terms of transmission properties, compactness, and flexibility. This solution was also experimentally validated using a WR-19 GSHGW operating from 35 to 63 GHz.
On the proximity of Ablowitz–Ladik and discrete nonlinear Schrödinger models: A theoretical and numerical study of Kuznetsov-Ma solutions
(Elsevier, 2025-08) Lytle, Madison L.; Charalampidis, Efstathios G.; Mantzavinos, Dionyssios; Cuevas-Maraver, Jesús; Kevrekidis, Panayotis G.; Karachalios, Nikos I.; Universidad de Sevilla. Departamento de Física Aplicada I; National Science Foundation (NSF). United States; European Union (UE); Universidad de Sevilla. FQM280: Física no Lineal
In this work, we investigate the formation of time-periodic solutions with a non-zero background that emulate rogue waves, known as Kuznetsov-Ma (KM) breathers, in physically relevant lattice nonlinear dynamical systems. Starting from the completely integrable Ablowitz–Ladik (AL) model, we demonstrate that the evolution of KM initial data is proximal to that of the non-integrable discrete Nonlinear Schrödinger (DNLS) equation for certain parameter values of the background amplitude and breather frequency. This finding prompts us to investigate the distance (in certain norms) between the evolved solutions of both models, for which we rigorously derive and numerically confirm an upper bound. Finally, our studies are complemented by a two-parameter (background amplitude and frequency) bifurcation analysis of numerically exact, KM-type breather solutions of the DNLS equation. Alongside the stability analysis of these waveforms reported herein, this work additionally showcases potential parameter regimes where such waveforms with a flat background may emerge in the DNLS setting.
Compositional and microstructural study of joining methods in archaeological gold objects
(John Wiley and Sons Ltd, 2017-03) Scrivano, Simona; Gómez-Tubio, Blanca María; Ortega-Feliú, Inés; Ager Vázquez, Francisco José; Paúl Escolano, Antonio; Universidad de Sevilla. Departamento de Física Atómica, Molecular y Nuclear; Universidad de Sevilla. Departamento de Física Aplicada III; Universidad de Sevilla. Departamento de Física Aplicada I; Universidad de Sevilla. Departamento de Ingeniería y Ciencia de los Materiales y del Transporte; Ministerio de Economía y Competitividad (MINECO). España
This work arises in response to the need to understand the production techniques of pre-roman gold jewels, starting from the systematic characterization of the different methods of metal joining used in antiquity to produce these objects. To meet this requirement, different procedures used in antiquity were reproduced by means of experimental archaeology. These models correspond to three metal-joining methods reported by ancient recipes: solid-state diffusion with copper salt, brazing and autogenous welding. These techniques were studied by different analytical methods in order to characterize them at both compositional and microstructural level (SEM-EDS, metallography, μ-XRF and μ-PIXE). The results obtained show that the solid-state diffusion bonding with copper salt presents a crystal hexagonal structure without phase changes in the joining point, where only a variation in the grain size is observed. At the compositional level, this soldering method is characterized by a local increase in copper concentration and a small decrease in gold content. In contrast, brazing shows a dendritic-porous structure due to the superposition of the soldering alloy and the crystal structure of the original foils. Besides, the compositional analysis revealed an increment of silver and copper concentrations and a simultaneous reduction of gold concentration. Finally, in the autogenous welding, no changes at the microstructural and compositional levels were observed. The results obtained have also demonstrated the usefulness of a portable μ-XRF system for the in-situ characterization of ancient jewels.
The complete solution of the Schrödinger equation with the Rosen–Morse type potential via the Nikiforov–Uvarov method
(Elsevier, 2024-02) Gordillo Núñez, Guillermo; Álvarez Nodarse, Renato; Quintero, Niurka R.; Universidad de Sevilla. Departamento de Física Aplicada I; Ministerio de Ciencia e Innovación (MICIN). España; European Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER); Junta de Andalucía; Universidad de Granada; Andalusian research group; Universidad de Sevilla. FQM415: Modelado Físico-Matemático de Sistemas no Lineales
We determine exact solutions of the time-independent Schrödinger equation for the Rosen–Morse type potential by using the Nikiforov–Uvarov method. This method allows us to write the eigenfunctions of the Schrödinger equation as the product of two simpler functions in a constructive way. The resolution of this problem is used to show that the kinks of the non-linear Klein–Gordon equation with 𝜑2𝑝+2 type potentials are stable. We also derive the orthogonality and completeness relations satisfied by the set of eigenfunctions, which are useful in the description of the dynamics of kinks under perturbations or interacting with antikinks.
Picosecond lifetimes of hydrogen bonds in the halide perovskite CH₃NH₃PbBr₃
(American Chemical Society, 2024-11-26) Garrote Márquez, Alejandro; Lodeiro Moraga, Lucas; Cruz Hernández, Norge; Liang, Xia; Walsh, Aron; Menéndez-Proupin, Eduardo; Universidad de Sevilla. Departamento de Física Aplicada I; Universidad de Sevilla. FQM401: Simulación y Aplicación de Materiales
The structures and properties of organic–inorganic perovskites are influenced by the hydrogen bonding between the organic cations and the inorganic octahedral networks. This study explores the dynamics of hydrogen bonds in CH3NH3PbBr3 across a temperature range from 70 to 350 K, using molecular dynamics simulations with machine-learning force fields. The results indicate that the lifetime of hydrogen bonds decreases with increasing temperature from 7.6 ps (70 K) to 0.16 ps (350 K), exhibiting Arrhenius-type behavior. The geometric conditions for hydrogen bonding, which include bond lengths and angles, maintain consistency across the full temperature range. The relevance of hydrogen bonds for the vibrational states of the material is also evidenced through a detailed analysis of the vibrational power spectra, demonstrating their significant effect on the physical properties for this class of perovskites.
Investigación multidisciplinar basada en el uso de aceleradores de partículas: el Centro Nacional de Aceleradores
(Fundación General de la Universidad Autónoma de Madrid, 2024-09) López Gutiérrez, José María; García-Tenorio García-Balmaseda, Rafael; Universidad de Sevilla. Departamento de Física Aplicada I; Universidad de Sevilla. RNM138: Física Nuclear Aplicada
En este artículo se lleva a cabo un análisis descriptivo a distintos niveles del Centro Nacional de Aceleradores, dedicado fundamentalmente a la realización de investigaciones multidisciplinares basadas en el uso de aceleradores de partículas y equipos asociados. En el artículo se hace así referencia a las seis instalaciones principales que posee este centro y a las distintas líneas de investigación asociadas a ellas. Igualmente se describe la estructura de recursos personales que posee, y que integra un conjunto de sesenta personas, mencionándose igualmente las características orientadas a los usuarios externos del centro a través de las actividades de carácter transversal que desarrolla y a las colaboraciones estratégicas con empresas e instituciones que viene poniendo en práctica en los últimos años.
Mechanisms of de-icing by surface rayleigh and plate lamb acoustic waves
(Wiley, 2024-12) Pandey, Shilpi; Moral Jalón, Jaime del; Jacob, Stefan; Montes Montañez, Laura; Gil Rostra, Jorge; Frechilla Zabal, Alejandro; Karimzadeh, Atefeh; Rico-Gavira, Víctor Joaquín ; Kanter, Raul; Kandelin, Niklas; López Santos, Carmen; Koivuluoto, Heli; Angurel Lambán, Luis Alberto; Winkler, Andreas; Borrás Martos, Ana Isabel; Rodríguez González-Elipe, Agustín; Universidad de Sevilla. Departamento de Física Aplicada I; Agencia Estatal de Investigación. España; European Union (UE). H2020
Acoustic waves (AW) have recently emerged as an energy-efficient ice-removal procedure compatible with functional and industrial-relevant substrates. However, critical aspects at fundamental and experimental levels have yet to be disclosed to optimize their operational conditions. Identifying the processes and mechanisms by which different types of AWs induce de-icing are some of these issues. Herein, using model LiNbO3 systems and two types of interdigitated transducers, the e-icing and anti-icing efficiencies and mechanisms driven by Rayleigh surface acoustic waves (R-SAW) and Lamb waves with 120 and 510 μm wavelengths, respectively, are analyzed. Through the experimental analysis of de-icing and active anti-icing processes and the finite element simulation of the AW generation, propagation, and interaction with small ice aggregates, it is disclosed that Lamb waves are more favorable than R-SAWs to induce de-icing and/or prevent the freezing of small ice droplets. Prospects for applications of this study are supported by proof of concept experiments, including de-icing in an icing wind tunnel, demonstrating that Lamb waves can efficiently remove ice layers covering large LN substrates. Results indicate that the de-icing mechanism may differ for Lamb waves or R-SAWs and that the wavelength must be considered as an important parameter for controlling the efficiency.
The dissipative effect of Caputo–time-fractional derivatives and its implications for the solutions of nonlinear wave equations
(Elsevier, 2024-09) Bountis, Tassos; Cantisán Gómez, Julia; Cuevas-Maraver, Jesús; Macías Díaz, Jorge Eduardo; Kevrekidis, Panayotis G.; Universidad de Sevilla. Departamento de Física Aplicada I; Agencia Estatal de Investigación. España; European Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER); Universidad de Sevilla. FQM280: Física no Lineal
In honor of the great Russian mathematician A. N. Kolmogorov, we would like to draw attention in the present paper to a curious mathematical observation concerning fractional differential equations describing physical systems, whose time evolution for integer derivatives has a time-honored conservative form. This observation, although known to the general mathematical community, (Achar et al., 2001; Stanislavsky, 2004; Diethelm and Ford, 2010; Chung and Jung, 2014; Olivar-Romero and Rosas-Ortiz, 2017; Baleanu et al., 2020) has not, in our view, been satisfactorily addressed. More specifically, we follow the recent exploration of Caputo–Riesz time–space-fractional nonlinear wave equation of Macias Diaz (2022), in which two of the present authors introduced an energy-type functional and proposed a finite-difference scheme to approximate the solutions of the continuous model. The relevant Klein–Gordon equation considered here has the form: 𝜕𝛽𝜙(𝑥, 𝑡) - 𝜕𝑡𝛽 − 𝛥 𝛼𝜙(𝑥, 𝑡) + 𝐹′(𝜙(𝑥, 𝑡)) = 0, ∀(𝑥, 𝑡) ∈ (−∞, ∞) (0.1) where we explore the sine-Gordon nonlinearity 𝐹(𝜙) = 1 − cos(𝜙) with smooth initial data. For 𝛼 = 𝛽 = 2, we naturally retrieve the exact, analytical form of breather waves expected from the literature. Focusing on the Caputo temporal derivative variation within 1 < 𝛽 < 2 values for 𝛼 = 2, however, we observe artificial dissipative effects, which lead to complete breather disappearance, over a time scale depending on the value of 𝛽. We compare such findings to single degree-of-freedom linear and nonlinear oscillators in the presence of Caputo temporal derivatives and also consider anti-damping mechanisms to counter the relevant effect. These findings also motivate some interesting directions for further study, e.g., regarding the consideration of topological solitary waves, such as kinks/antikinks and their dynamical evolution in this model.
On the fractional dynamics of kinks in sine-Gordon models
(MDPI, 2025-01-10) Bountis, Tassos; Cantisán Gómez, Julia; Cuevas-Maraver, Jesús; Macías Díaz, Jorge Eduardo; Kevrekidis, Panayotis G.; Universidad de Sevilla. Departamento de Física Aplicada I; National Science Foundation (NSF). United States; European Union (UE); Agencia Estatal de Investigación. España; Universidad de Sevilla. FQM280: Física no Lineal
I the present work, we explored the dynamics of single kinks, kink–anti-kink pairs and bound states in the prototypical fractional Klein–Gordon example of the sine-Gordon equation. In particular, we modified the order 𝛽 of the temporal derivative to that of a Caputo fractional type and found that, for 1<𝛽<2, this imposes a dissipative dynamical behavior on the coherent structures. We also examined the variation of a fractional Riesz order 𝛼 on the spatial derivative. Here, depending on whether this order was below or above the harmonic value 𝛼=2, we found, respectively, monotonically attracting kinks, or non-monotonic and potentially attracting or repelling kinks, with a saddle equilibrium separating the two. Finally, we also explored the interplay of the two derivatives, when both Caputo temporal and Riesz spatial derivatives are involved.
Discrete derivative nonlinear Schrödinger equations
(MDPI, 2024-12-30) Hennig, Dirk; Cuevas-Maraver, Jesús; Universidad de Sevilla. Departamento de Física Aplicada I; Universidad de Sevilla. FQM280: Física no Lineal
We consider novel discrete derivative nonlinear Schrödinger equations (ddNLSs). Taking the continuum derivative nonlinear Schrödinger equation (dNLS), we use for the discretisation of the derivative the forward, backward, and central difference schemes, respectively, and term the corresponding equations forward, backward, and central ddNLSs. We show that in contrast to the dNLS, which is completely integrable and supports soliton solutions, the forward and backward ddNLSs can be either dissipative or expansive. As a consequence, solutions of the forward and backward ddNLSs behave drastically differently compared to those of the (integrable) dNLS. For the dissipative forward ddNLS, all solutions decay asymptotically to zero, whereas for the expansive forward ddNLS all solutions grow exponentially in time, features that are not present in the dynamics of the (integrable) dNLS. In comparison, the central ddNLS is characterized by conservative dynamics. Remarkably, for the central ddNLS the total momentum is conserved, allowing the existence of solitary travelling wave (TW) solutions. In fact, we prove the existence of solitary TWs, facilitating Schauder’s fixed-point theorem. For the damped forward expansive ddNLS we demonstrate that there exists such a balance of dissipation so that solitary stationary modes exist.
Investigation of the Growth Mechanisms of a-CHₓ Coatings Deposited by Pulsed Reactive Magnetron Sputtering
(American Chemical Society, 2012-05-08) López Santos, Carmen; Colaux, J. L.; González, J. C.; Lucas, S.; Universidad de Sevilla. Departamento de Física Aplicada I; European Commission (EC)
The study of the growth mechanisms of amorphous hydrogenated carbon coatings (a-CHₓ) deposited by reactive pulsed magnetron discharge in Ar + C2H₂, Ar + H₂, and Ar + C₂H₂ + H₂ low-pressure atmospheres is presented in this work. Hydrogen-containing species of the reactant gas affect the microstructure and surface properties of the a-CHₓ thin films. The dynamic scaling theory has been used to relate the main reactive species involved in the deposition process to the growth mechanisms of the thin film by means of the analysis of the roughness evolution. Anomalous scaling effects have been observed in smooth a-CHₓ coatings. Dynamic scaling exponents α, β, and z indicate a general growth controlled by surface diffusion mechanisms. Hydrogen species have an influence on the lateral growth of the a-CHₓ coatings and are involved in the development of a polymeric-like structure. Meanwhile, hydrocarbon species promote the generation of higher aggregates, which increases the roughness of a more sp² clustering structure of the a-CHₓ coating.
Lateral and in-depth distribution of functional groups on diamond-like carbon after oxygen plasma treatments
(Elsevier, 2011-02) López Santos, Carmen; Yubero Valencia, Francisco; Cotrino Bautista, José; Rodríguez González-Elipe, Agustín; Universidad de Sevilla. Departamento de Física Aplicada I; Universidad de Sevilla. Departamento de Física Atómica, Molecular y Nuclear; Ministerio de Ciencia y Educación. España; Junta de Andalucía; Universidad de Sevilla. FQM-196: Nanotecnología en Superficies y Plasma
A diamond like carbon material has been exposed to a low pressure microwave and atmospheric pressure plasma of oxygen to enhance its hydrophilicity and surface energy. For comparison, data are also reported after activation with a beam of neutral atoms of oxygen. The surface incorporation of oxygenated functional groups and the determination of the in-depth distribution of this element have been analysed by means of the X ray photoemission spectroscopy (XPS). Atomic force microscopy (AFM) has been used to get information of the surface topography and, by recording friction maps of the surface, the lateral distribution of oxygenated functional groups formed after the different activation treatments. Differences in surface composition, topography and in-depth and lateral distribution of oxygen have been correlated with the intrinsic characteristics of the activation plasma processes.
Bioactivity and hemocompatibility study of amorphous hydrogenated carbon coatings produced by pulsed magnetron discharge
(Wiley, 2012-12-05) López Santos, Carmen; Colaux, J. L.; Laloy, J.; Fransolet, M.; Mullier, F.; Michiels, C.; Dogné, J. M.; Lucas, S.; Universidad de Sevilla. Departamento de Física Aplicada I
Literature contains very few data about the potential biomedical application of amorphous hydrogenated carbon (a-C:H) thin films deposited by reactive pulsed magnetron discharge even so it is one of the most scalable plasma deposition technique. In this article, we show that such a C2H2 pulsed magnetron plasma produces high quality coating with good hemocompatibility and bioactive response: no effect on hemolysis and hemostasis were observed, and proliferation of various cell types such as endothelial, fibroblast, and osteoblast-like cells was not affected when the deposition conditions were varied. Cell growth on a-C:H coatings is proposed to take place by a two-step process: the initial cell contact is affected by the smooth topography of the a-C:H coatings, whereas the polymeric-like structure, together with a moderate hydrophilicity and a high hydrogen content, directs the posterior cell spreading while preserving the hemocompatible behavior.
Fluoride exposure duringintrauterine and lactation periods promotes changes in the offspring rats' alveolar bone
(Elsevier, 2022-11) Ferreira, Maria Karolina Martins; Souza-Monteiro, Deiweson; Bittencourt, Leonardo Oliveira; Matos-Sousa, José Mário; Chemelo, Victória Santos; Santos, Vinicius Ruan Neves; Nunes, Paula Beatriz Oliveira; Balbinot, Gabriela de Souza; Prado, Alejandro Ferraz; Collares, Fabricio Mezzomo; Ager Vázquez, Francisco José; Ortega-Feliú, Inés; Respaldiza Galisteo, Miguel Ángel; Pessanha, Sofia; Lima, Rafael Rodrigues; Universidad de Sevilla. Departamento de Física Aplicada I; Universidad de Sevilla. Departamento de Física Aplicada III; Universidad de Sevilla. Departamento de Física Atómica, Molecular y Nuclear; Universidad de Sevilla. RNM138: Física Nuclear Aplicada
The importance of fluoride (F) for oral health is well established in the literature. However, evidence suggests that excessive exposure to this mineral is associated with adverse effects at different life stages and may affect many biological systems, especially mineralized tissues. The purpose of this study was to investigate the effects of F exposure during pregnancy and breastfeeding on the alveolar bone of the offspring since the alveolar bone is one of the supporting components of the dental elements. For this, the progeny rats were divided into three groups: control, 10 mg F/L, and 50 mg F/L for 42 (gestational and lactation periods). Analysis of the quantification of F levels in the alveolar bone by particle-induced gamma emission; Raman spectroscopy to investigate the physicochemical aspects and mineral components; computed microtomography to evaluate the alveolar bone microstructure and analyses were performed to evaluate osteocyte density and collagen quantification using polarized light microscopy. The results showed an increase in F levels in the alveolar bone, promoted changes in the chemical components in the bone of the 50 mg F/L animals (p < 0.001), and had repercussions on the microstructure of the alveolar bone, evidenced in the 10 mg F/L and 50 mg F/L groups (p < 0.001). Furthermore, F was able to modulate the content of organic bone matrix, mainly collagen; thus, this damage possibly reduced the amount of bone tissue and consequently increased the root exposure area of the exposed groups in comparison to a control group (p < 0.001). Our findings reveal that Fcan modulate the physicochemical and microstructural dimensions and reduction of alveolar bone height, increasing the exposed root region of the offspring during the prenatal and postnatal period. These findings suggest that F can modulate alveolar bone mechanical strength and force dissipation functionality.
Molecular simulation study of the glass transition in a soft primitive model for ionic liquids
(Taylor and Francis Group, 2019-10-07) Rodríguez Rivas, Álvaro; Romero Enrique, José Manuel; Rull Fernández, Luis Felipe; Universidad de Sevilla. Departamento de Física Atómica, Molecular y Nuclear; Universidad de Sevilla. Departamento de Física Aplicada I; Ministerio de Economía y Competitividad (MINECO). España; European Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER); Junta de Extremadura
In this paper, we present a molecular dynamics study of the glass transition for a soft-core primitive model for ionic liquids, in which cations are fully flexible chains of tangent soft spherical monomers, being the positively charged monomer at one of the ends of the chain, and anions as charged soft spheres. We have monitored transport coefficients such as the self-diffusion coefficients and the shear viscosity, as well as correlation functions such as the mean-square displacement, the self-intermediate scattering function, and probes of heterogeneous dynamics such as the van Hove distribution function and the four-points susceptibility. The analysis of these properties indicates that, for a given pressure, the glass transition shows a weak temperature dependence on the cation length, occurring first for short-chain than for long-chain ionic liquids.
Update on numerical model for the performance prediction of a PEM Fuel Cell
(Elsevier, 2011-07) Iranzo Paricio, José Alfredo; Muñoz, Miguel; Pino Lucena, Francisco Javier; Rosa Iglesias, Manuel Felipe; Universidad de Sevilla. Departamento de Ingeniería Energética; Junta de Andalucía
A Computational Fluid Dynamics (CFD) model developed for a 50 cm2 Fuel Cell with parallel and serpentine flow field bipolar plates was presented in an article published in the International Journal of Hydrogen Energy 35 (2010) 11,533–11,550 [1]. The experimental validation details were presented as well in an article published in the International Journal of Hydrogen Energy 35 (2010) 11,437–11,447 [2]. A good agreement between numerical results and experimental measurements were obtained except for the high current density region where mass-transport limitations dominate the voltage loss. This short communication presents an update on the last simulations performed, where an improved prediction of the polarization curve is obtained. The physical and computational aspects of the reasons underlying the improvement of the results are discussed.
Land-to-sea indicators of the Zanclean megaflood
(Springer Nature, 2024) Micallef, Aaron; Barreca, Giovanni; Hübscher, Christian; Camerlenghi, Angelo; Carling, Paul; Abril Hernández, José María; Periáñez Rodríguez, Raúl; Caruso, Antonio; Universidad de Sevilla. Departamento de Física Aplicada I
One debated scenario for the termination of the Messinian salinity crisis 5.33 million years ago is cataclysmic refilling of the Mediterranean Sea through the Zanclean megaflood. Here we present a clear line of onshore-to-offshore evidence for this megaflood spilling over a shallow-water marine corridor in south-east Sicily into the nearby subaqueous Noto Canyon: (i) >300 asymmetric and streamlined erosional ridges aligned with the megaflood direction, (ii) poorly-sorted breccia deposited between the Messinian and Lower Zanclean Trubi Formations, (iii) soft-sediment deformation structures and clastic injections in the breccia and underlying units, and (iv) a 20 kilometre wide erosional shelf channel connecting the ridges with Noto Canyon. Numerical modelling results support the modulation of flow velocity and direction by the excavation of the channel and Noto Canyon. Our findings demonstrate that the Messinian salinity crisis was terminated through a cataclysmic flood, which implies pronounced Mediterranean sea-level drawdown prior to the flooding.
Universal heat superdiffusion in one-dimensional nonequilibrium lattices
(American Physical Society, 2024) Ren, Yuanyang; Wang, Yang; Wu, Kai; Cubero Gómez, David; Universidad de Sevilla. Departamento de Física Aplicada I; Ministerio de Ciencia e Innovación (MICIN). España; National Joint Laboratory for Electric Power Technology
We propose a generalized Fourier's law, based on recent mode-coupling calculations, for one-dimensional nonlinear lattices in nonequilibrium simulations, where the boundaries are kept at different temperatures. Though not useful for the typical textbook numerical examples, we are able to demonstrate numerically the theory for an anharmonic lattice with force field parameters similar to those of realistic low-dimensional structures such as covalently bonded molecular chains or carbon nanotubes, specifically showing that the asymptotic heat conductivity is described by the mode-coupling theory in good approximation, without any adjustable parameter.

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