Feeding Versus Feedback in NGC1068 probed with Gemini NIFS. I. Excitation

We present emission-line flux distributions and ratios for the inner 200pc of the narrow-line region of the Seyfert2 galaxy NGC1068, using observations obtained with the Gemini Near-infrared Integral Field Spectrograph (NIFS) in the J, H and K bands at a spatial resolution of 10pc and spectral resolution of 5300. The molecular gas emission - traced by the K-band H_2 emission lines - outlines an off-centered circumnuclear ring with a radius of 100pc showing thermal excitation. The ionized gas emission lines show flux distributions mostly outlining the previously known [OIII]5007 ionization bicone. But while the flux distributions in the HI and HeII emission lines are very similar to that observed in [OIII], the flux distribution in the [FeII] emission lines is more extended and broader than a cone close to the nucleus, showing a "double bowl" or `hourglass" structure". This difference is attributed to the fact that the [FeII] emission, besides coming from the fully ionized region, comes also from the more extended partially ionized regions, in gas excited mainly by X-rays from the active galactic nucleus. A contribution to the [FeII] emission from shocks along the bicone axis to NE and SW of the nucleus is also supported by the enhancement of the [FeII](1.2570)/[PII](1.1885) and [FeII](1.2570)/Pabeta emission-line ratios at these locations and is attributed to the interaction of the radio jet with the NLR. The mass of ionized gas in the inner 200pc of NGC1068 is MHII~2.2E4 M_Sun, while the mass of the H2 emitting gas is only M_{H2}~29M_Sun. Taking into account the dominant contribution of the cold molecular gas, we obtain an estimate of the total molecular gas mass of Mcold~2E7 M_Sun.Comment: accepeted for publication in MNRA

Dispositivo portamuestras para medidas simultáneas utilizando radiación de sincrotrón

Referencia OEPM: P200001388.-- Fecha de solicitud: 31/05/2000.-- Titular: Consejo Superior de Investigaciones Científicas (CSIC).Dispositivo portamuestras para medidas simultáneas utilizando radiación de sincrotrón (ver figura en archivo de texto adjunto). La presente invención describe el desarrollo de un nuevo prototipo de portamuestras para utilización simultánea en una línea de difracción de rayos-X utilizando la para detección simultánea de dispersión en ángulos altos y bajos y espectroscopia dieléctrica. El prototipo consiste en: (i) dos bloques metálicos con cuatro resistencias calefactoras empotradas que permiten calentar los bloques metálicos y la muestra hasta 350ºC. Uno de los bloques esta atravesado por un tubo en forma de U por el cual circula aire de refrigeración y que al mismo tiempo conecta el bloque principal del portamuestras con la tapa; (ii) dos discos metálicos con orificios efectuados en el centro (electrodos); (iii) dos discos finos de aluminio; (iv) una placa superior (tapa), para cerrar el horno donde se introduce el portamuestras, con las correspondientes conexiones para el cableado.Peer reviewe

Evidence of early stage precursors of polymer crystals by dielectric spectroscopy

Dielectric spectra of the polyester poly(propylene succinate) were measured upon crystallization. For this model aliphatic polyester the α and β relaxations appear simultaneously and are well resolved in the experimental frequency window. During isothermal crystallization, this fact allows one to use the β relaxation to characterize the crystalline structural development while the α relaxation provides information about the evolution of the amorphous phase dynamics. In this way structure development and dynamics evolution can be characterized by a single experiment during the crystallization process. The unambiguous analysis of the dielectric loss clearly supports the existence of precursors of crystallization in the induction period. © 2007 The American Physical Society.Finnancial support from the MCYT (Grant No. MAT2005-01768), Spain.Peer Reviewe

Broadband ac conductivity of conductor-polymer composites

The electrical conductivity of a composite model system formed by highly structured carbon black (CB) filled, within an amorphous polymer, poly(ethylene terephtalate) composite is studied. The dc conductivity as a function of CB content follows a scaling law of the type σ∝(p−pc)t yielding for the percolation concentration, pc=0.011 and for the exponent, t=2.17. The analysis of the temperature dependence of the conductivity suggests that for temperatures larger than 45 K, conduction can be ascribed to thermal fluctuation induced tunneling of the charge carriers through the insulating layer of polymer separating two CB aggregates. At lower temperatures, conductivity becomes temperature independent, which is typical of conventional tunneling. The frequency dependence of the conductivity is also studied between dc and 109 Hz. By the introduction of a shift factor ap, a procedure for the construction of a master curve based on a “time-length equivalence principle” is proposed. Finally, a model is introduced to describe the frequency dependence of the conductivity of CB-filled composites based on the behavior of charge carriers placed in a fractal object

Expected and unexpected behavior of the orientational order and dynamics induced by azobenzene solutes in a nematic

We have explored the changes in the phase stability, orientational order, and dynamics of the nematic 4-cyano-4¢-n-pentylbiphenyl (5CB) doped with either the trans or the cis form of different p-azobenzene derivatives using the ESR spin-probe technique. In particular, we have studied the effects induced by each of the seven nonmesogenic 4-R-phenylazobenzenes (R = H, F, Br, CH3, CF3, On-Bu, Ot-Bu) at 1% and 7% mole fraction on the order parameter and on the shift of the nematic-isotropic transition temperature (TNI), as reported by a nitroxide spin probe, and we have tried to relate them to the solute shape and charge distribution. In all the cases the presence of the azo-derivative causes a depression of TNI, more pronounced for the cis isomers. The dependence of on the reduced temperature T*=T/TNI remains the same as that of pure 5CB in all trans-doped samples at 1% and 7% and decreases only slightly in the cis at 1%. However, we observe different and in some cases large variations (up to 25%) in for the cis at 7%, showing solute effects that go beyond the shift in TNI. Surprisingly enough, even at the highest concentration, the probe dynamics appears to be essentially independent of the nature, the configuration, and the concentration of the different solutes and very similar to that observed in the pure 5CB

Simultaneous crystalline-amorphous phase evolution during crystallization of polymer systems

Despite the fact that polymer crystallization has been the object of intense research, this process is far from being fully understood. Traditional polymer crystallization studies using X-ray scattering techniques mainly provide information about the ordered regions. To obtain a more complete information about the time evolution of both the crystalline and the amorphous phase during polymer crystallization, we have developed a technique which allows one to obtain information about both the crystalline and the amorphous phase simultaneously. We report here simultaneous information about three key aspects of the isothermal polymer crystallization process: i) polymer chain ordering, through Wide-Angle X-ray Scattering; ii) lamellar crystals arrangement, through Small-Angle X-ray Scattering; iii) amorphous phase evolution through dielectric spectroscopy. Our results probe that during primary crystallization the average mobility of the amorphous phase is not notably affected. Upon passing through the crossover time, marking the transition from primary to secondary crystallization, the restriction to the mobility of the amorphous phase mainly occurs in the regions between the lamellar stacks regions and not in the amorphous regions within the lamellar stacks. We hypothesize that molecular mobility in the amorphous regions located between consecutive crystals become strongly arrested as soon as the lamellar stack is formed. © EDP SciencesMCYT (grants FPA2001-2139, BMF2000-1474), Spain. MEC “Científicos y Tecnólogos Extranjeros” program. IHP-Contract HPRI-CT-1999-00040 of the European Commission (EC(ERBFMGEDT 950059) and II-00-015 EC).Peer Reviewe

Laser nanostructuring of polymers: Ripples and applications

Polymer nanostructures and nanopatterns are being profusely used for developing next-generation organic devices with analytical and biological functions and photonic applications. Laser based strategies constitute an advantageous approach for the assembly and control of this type of soft matter nanostructures as they afford the sought versatility and reliability. Recent and on-going research on laser nanostructuring of thin films of synthetic polymers and natural biopolymers will be exemplified by studies on the generation of laser induced periodic surface structures (LIPSS) and their use for surface enhanced Raman spectroscopy (SERS) based sensors. © 2012 American Institute of PhysicsFunded by MICINN, Spain, Projects CTQ2010-15680 and MAT2009-07789. MICINN, Spain, Juan de la Cierva contract and an FPI fellowshipPeer Reviewe

Tunable electromagnetic interference shielding properties of binary thermoplastic composites prepared by reactive microencapsulation

The Supporting Information is available free of charge at: https://pubs.acs.org/doi/10.1021/acsapm.2c00084Thermoplastic composites integrating carbon nanotubes (CNT) and micron-sized metal particles dispersed in polymer matrices can address emerging multifunctional needs, e.g., good electrical conductivity and electromagnetic interference (EMI) shielding combined with easy processing and affordable costs. Herein, an approach based on reactive microencapsulation is reported to prepare polyamide 6 (PA6)-based composites comprising binary loads of CNT and Al, Cu, or Fe particles. The microencapsulation is performed by activated anionic polymerization of ε-caprolactam in solution, in the presence of the metal/CNT loads. The resulting hybrid microparticles are compression-molded into plates containing effective metal/CNT loads in the range of 12–17 wt %. Among the materials synthesized, the one containing Al/CNT binary load (3:7 wt %) displays the highest EMI shielding effectiveness (SE) of 43.5 dB at 12 GHz, with a 2 mm thickness and an electrical conductivity σdc of 6.61 × 10–3 S/cm. A synergetic effect is observed in all of the metal/CNT PA6 samples in terms of both σdc and SE increase. Evidently, the presence of metal particles well dispersed in the conductive CNT network contributes to the mobility of the carriers and thus to the effective attenuation of the electromagnetic waves. Therefore, the binary composites of this study can be efficient thermoplastic EMI shielding materials.The authors gratefully acknowledge the technical support of Hugo Mostardinha from the Instituto de Telecomunicações Aveiro during the EMI shielding measurements and the financial support of Fundação para a Ciência e Tecnologia (FCT), Project UID/CTM/50025/2019. F.M.O. thanks FCT for the Ph.D. grant PD/BD/114372/2016 (AdvaMTech Ph.D. Program in Advanced Materials and Processing). The assistance of Prof. Nuno Carvalho from the University of Aveiro, Portugal, in the EMI shielding experiments is also gratefully acknowledged

Propuesta de curva S-N de diseño para aceros estructurales con bordes rectos cortados por plasma

Este artículo presenta una propuesta de curva de diseño a fatiga para aceros estructurales con bordes rectos cortados por plasma. El corte por plasma se enmarca, junto al oxicorte y al corte láser, dentro de los métodos de corte térmico. En relación con la vida en fatiga de componentes cortados mediante corte térmico la práctica totalidad de las normas de diseño consideran únicamente el oxicorte, sin que exista respaldo normativo para cortes realizados por plasma o por láser. Por este motivo se presenta en este documento un programa experimental de fatiga (S-N) sobre cuatro aceros (S355M, S460M, S690Q y S890Q) con bordes rectos cortados por plasma. Los resultados obtenidos para cada una de las 40 probetas ensayadas se han usado para determinar la correspondiente clase FAT del Eurocódigo, que ha sido validada finalmente con una amplia revisión de los resultados obtenidos en la literatura especializada.This paper presents a proposal of fatigue design curves for structural steels containing plasma cut straight edges. Plasma cutting is, together with flame cutting and laser cutting, one of the thermal cutting technologies. Concerning the fatigue performance of thermally cut structural components, design standards provide design curves for flame cut straight edges, but both plasma and laser cut straight edges are not covered. For this reason this document presents a fatigue experimental program (S-N) with four steels (S355M, S460M, S690Q y S890Q) presenting plasma cut straight edges. The obtained results in the 40 tested specimens have been used to derive the corresponding Eurocode FAT class, which has been finally validated through its application to a wide number of tests found in the literature.Los autores de este trabajo desean agradecer a la Comisión Europea la financiación del proyecto HIPERCUT: “High Performance Cut Edges in Structural Steel Plates for Demanding Aplications” (RFSR-CT-2012-00027), de cuyos resultados se deriva este artículo

Electrically conductive PTT-block-PTMO/SWCNTs+Graphene Nanoplatelets hybrid nanocomposites prepared by in situ polymerization

Hybrid Materials 2015; Sitges, Barcelona, Spain, 9 - 13 March 2015The studies were financed by the National Science Centre within project PRELUDE no 2013/11/N/ST8/00404.Peer Reviewe