Micro-Raman and Raman Imaging studies of glassy material produced by continuous wave (CW) CO2 laser irradiation of lime/pozzolan mortar

ICCC 2015, Beijing, China, 13~16 October 2015; http://iccc2015.csp.escience.cn/dct/page/1This work describes the distribution of the portlandite over the surface of the lime/pozzolan mortar and the mineral composition of the glassy material formed when the mortar was irradiated with continuous-wave-CO2 (CW-CO2) laser. Both Micro-Raman and Raman mapping have been used for structural studies. Lime/pozzolan/sand 1/1/2 mortars, 5 years at room temperature, were irradiated with CW-CO2 laser (Synrad Firestar t80, Mukilteo, WA) operating at a wavelength of 10.591 ¿m, 10P(20) CO2 laser line. Laser output: 8W, 18W and 38W (Synrad PW-250 (Mukilteo, WA)). The laser beam was focused by means of a NaCl lens of 10 cm focal length and the irradiation time was 5 seconds. Raman spectra were collected with a Raman Spectrometer (Renishaw Invia) equipped with a CCD camera, using 532 nm (Nd:YAG) excitation line. The laser on the sample was 5 mW and the integration time was 10 seconds. For mapping measurements, an area of 80 ¿m x 80 ¿m was chosen in the internal part of the glass. The step size was 5 ¿m with an individual grid size of 25 ¿m2. Glazing, vaporization and spalling process can produce over an irradiated surface with a high power laser beam. When the power density of the irradiating laser beam is high enough to raise the temperature beyond the glass transition, a glassy surface layer is formed. However, if surface temperatures are below that melting point, the vaporization of water can be produce over the material surface. Due to the small diffusivity of water vapour, its transport is hindered and an overpressure is attained. Hydraulic building materials have about 4-10% bounded water, after irradiation with the CW-CO2 laser, water vapour spread out in a vaporization front reacting with the CaO present in the sample and producing Ca(OH)2, besides a glassy surface.Peer Reviewe

Eficacia del programa de intervención funcional del lenguaje Flip-N en niños con TEL

105 p.Este trabajo de investigación estudia la eficacia del programa de intervención funcional FLIP-N en el desempeño narrativo de un grupo de 6 niños cuyas edades fluctúan entre 5.4 y 6 años de edad, todos con diagnóstico de trastorno específico del lenguaje (TEL). Los seis sujetos se distribuyeron en dos grupos, 3 en el grupo control (sin intervención) y los otros 3 en el grupo experimental (con intervención), con pre y post-test. La intervención consistió en un total de 14 sesiones, una sesión a la semana con una duración aproximada de 40 a 60 minutos cada una de ellas. Se realizaron cuatro evaluaciones inter-sesiones aplicadas a ambos grupos. Se realizó un análisis descriptivo de los resultados. Los sujetos pertenecientes al grupo experimental lograron mejorar su desempeño narrativo, aunque este no fue en la magnitud esperada. Los sujetos del grupo control presentaron un comportamiento fluctuante, en donde uno de ellos resultó descendido en relación a su evaluación pre-test y los otros dos sujetos evidenciaron avances en su rendimiento narrativo. Se discuten las implicancias clínicas y los posibles factores que influirían en los resultados obtenidos. Palabras clave: trastorno específico del lenguaje, intervención, discurso narrativo, Programa FLIP-N./ABSTRACT: The aim of this work was to study the effect of the intervention program FLIP-N on the narrative performance of a group of six children aged between 5.5 and 6.0 years, all of them with a diagnosis of Specific Language Impairment (SLI). The six subjects were divided in two groups. Three of them were included in the control group (without intervention), and the other three were included in the experimental group (with intervention). A pretest-intervention-postest design was used. The intervention phase included 14 sessions, one session per week lasting from 40 to 60 minutes each. Four assessments were applied to both groups during the intervention phase. A descriptive analysis of the results was performed. The subjects in the experimental group improved their narrative performance, but it did not reach the expected magnitude. The control group showed a fluctuating behavior, because one of the children was dropped in relation to the pretest, but the other two subjects showed progress in their narrative performance. Clinical implications, and the possible factors involved are discussed. Key terms: Specific Language Impairment, intervention, narrative discourse, FLIP-N Program

Dynamics of multi-cored magnetic structures in the quiet Sun

We report on the dynamical interaction of quiet-Sun magnetic fields and granular convection in the solar photosphere as seen by \textsc{Sunrise}. We use high spatial resolution (0\farcs 15--0\farcs 18) and temporal cadence (33 s) spectropolarimetric Imaging Magnetograph eXperiment data, together with simultaneous CN and Ca\,\textsc{ii}\,H filtergrams from \textsc{Sunrise} Filter Imager. We apply the SIR inversion code to the polarimetric data in order to infer the line of sight velocity and vector magnetic field in the photosphere. The analysis reveals bundles of individual flux tubes evolving as a single entity during the entire 23 minute data set. The group shares a common canopy in the upper photospheric layers, while the individual tubes continually intensify, fragment and merge in the same way that chains of bright points in photometric observations have been reported to do. The evolution of the tube cores are driven by the local granular convection flows. They intensify when they are "compressed" by surrounding granules and split when they are "squeezed" between two moving granules. The resulting fragments are usually later regrouped in intergranular lanes by the granular flows. The continual intensification, fragmentation and coalescence of flux results in magnetic field oscillations of the global entity. From the observations we conclude that the magnetic field oscillations first reported by \citet{2011ApJ...730L..37M} correspond to the forcing by granular motions and not to characteristic oscillatory modes of thin flux tubes.Comment: 12 pages, 7 figures. Accepted in ApJ. Animation 1 can be downloaded from: http://spg.iaa.es/download

Time- and space-resolved spectroscopic characterization of laser-induced swine muscle tissue plasma

10 págs.; 12 figs.; 1 tab.The spatial-temporal evolution of muscle tissue sample plasma induced by a high-power transversely excited atmospheric (TEA) CO2 pulsed laser at vacuum conditions (0.1–0.01 Pa) has been investigated using high-resolution optical emission spectroscopy (OES) and imaging methods. The induced plasma shows mainly electronically excited neutral Na, K, C, Mg, H, Ca, N and O atoms, ionized C+, C2 +, C3 +, Mg+, Mg2 +, N+, N2 +, Ca+, O+ and O2 + species and molecular band systems of CN(B2Σ+–X2Σ+), C2(d3Πg–a3Πu), CH(B2Σ−–X2Π; A2Δ–X2Π), NH(A3Π–X3Σ−), OH(A2Σ+–X2 Σ+), and CaOH(B2Σ+–X2Σ+; A2Π–X2Σ+). Time-resolved two-dimensional emission spectroscopy is used to study the expanded distribution of different species ejected during ablation. Spatial and temporal variations of different atoms and ionic excited species are reported. Plasma parameters such as electron density and temperature were measured from the spatio-temporal analysis of different species. Average velocities of some plasma species were estimated. © 2015 Elsevier B.V. All rights reserved.We gratefully acknowledge the support received in part by the DGICYT (Spain) Project MICINN: CTQ2013-43086-P for this research. The authors wish to thank the Geomaterials2 Program (S2013/MIT 2914) supported by the Comunidad de Madrid and EU structural and cohesion funds (FSE and FEDER).Peer reviewe

Effective Dielectric Response of Metamaterials

We use a homogenization procedure for Maxwell's equations in order to obtain in the local limit the frequency ($\omega$) dependent macroscopic dielectric response $\epsilon^M(\omega)$ of metamaterials made of natural constituents with any geometrical shape repeated periodically with any structure. We illustrate the formalism calculating $\epsilon^M(\omega)$ for several structures. For dielectric rectangular inclusions within a conducting material we obtained a very anisotropic response which changes along one direction from conductor-like at low $\omega$ to a resonant dielectric-like at large $\omega$, attaining a very small reflectance at intermediate frequencies unrelated to surface plasmon excitation and which can be tuned through geometrycal tayloring. A similar behavior is obtained for other shapes close to the percolation threshold.Comment: 16 pages 7 figures. Accepted in Phys. Rev. B (2009-06-08

The history of a quiet-Sun magnetic element revealed by IMaX/SUNRISE

Isolated flux tubes are considered to be fundamental magnetic building blocks of the solar photosphere. Their formation is usually attributed to the concentration of magnetic field to kG strengths by the convective collapse mechanism. However, the small size of the magnetic elements in quiet-Sun areas has prevented this scenario from being studied in fully resolved structures. Here we report on the formation and subsequent evolution of one such photospheric magnetic flux tube, observed in the quiet Sun with unprecedented spatial resolution (0\farcs 15 - 0\farcs 18) and high temporal cadence (33 s). The observations were acquired by the Imaging Magnetograph Experiment (IMaX) aboard the \textsc{Sunrise} balloon-borne solar observatory. The equipartition field strength magnetic element is the result of the merging of several same polarity magnetic flux patches, including a footpoint of a previously emerged loop. The magnetic structure is then further intensified to kG field strengths by convective collapse. The fine structure found within the flux concentration reveals that the scenario is more complex than can be described by a thin flux tube model with bright points and downflow plumes being established near the edges of the kG magnetic feature. We also observe a daisy-like alignment of surrounding granules and a long-lived inflow towards the magnetic feature. After a subsequent weakening process, the field is again intensified to kG strengths. The area of the magnetic feature is seen to change in anti-phase with the field strength, while the brightness of the bright points and the speed of the downflows varies in phase. We also find a relation between the brightness of the bright point and the presence of upflows within it.Comment: 13 pages. Accepted in ApJ. Animation 1 can be viewed and downloaded from: http://spg.iaa.es/downloads.as

Use of Parsons-Lee and Onsager theories to predict nematic and demixing behavior in binary mixtures of hard rods and hard spheres

Parsons-Lee and Onsager theories are formulated for the isotropic-nematic transition in a binary mixture of hard rods and hard spheres. Results for the phase coexistence and for the equation of state in both phases for mixtures with different relative sizes and composition are presented. The two theories explain correctly the general behavior observed in experiments and computer simulations for these fluids. In particular, the theory accounts for the destabilization of the nematic phase when spherical or globular macromolecules are added to a system of rodlike colloids, and the entrance of the system into a demixed regime at high volume fractions of the spherical particles. Upon demixing a nematic state rich in rods coexists in equilibrium with an isotropic state much more diluted in the rodlike component. Onsager theory fails on quantitative grounds for aspect ratios of the rodlike molecules smaller than 100, and in the cases where the molar fractions of spheres becomes close to unity. On the contrary, the Parsons-Lee approximation remains accurate down to aspect ratios as small as 5. The spinodal analysis indicates that the isotropic-isotropic and nematic-nematic coexistences become feasible for sufficiently large spheres and long rods, respectively. The latter type of coexistence interferes partially with the isotropic-nematic coexistence regime of interest to the present work. Overall, the study serves to rationalize and control key aspects of the behavior of these binary nematogenic colloidal systems, which can be tuned with an appropriate choice of the relative size and molar fractions of the particles.Ministerio de Educación y Ciencia CTQ2004- 07730-C02 VEM2003-20574-C03Junta de Andalucía PAI FQM-205 FQM-31

Liquid crystal behavior of the Kihara fluid

The liquid crystal phases of the Kihara fluid have been studied in computer simulations. The work focuses on the isotropic–nematic–smectic-A triple point region, especially relevant for the understanding of the properties and the design of real mesogens with specific phase diagrams. The Kihara interaction resembles more appropriately than other related models, the shape of elongated polymers and biomolecules, and a closer assertion is provided for the role of the configurational entropy and the dispersive interactions in the behavior of such molecules in dense phases or under macromolecular crowding conditions.Dirección Genaral de Investigación Científico y Técnica BQU2001-3615-C02Instituto de Salud Carlos III 01/1664Plan Andaluz de Investigación FQM-205, FQM-31