Energy localization and shape transformations in semiflexible polymer rings

Shape transformations in driven and damped molecular chains are considered. Closed chains of weakly coupled molecular subunits under the action of spatially homogeneous time-periodic external field are studied. The coupling between the internal excitations and the bending degrees of freedom of the chain modifies the local bending rigidity of the chain. In the absence of driving the array takes a circular shape.When the energy pumped into the system exceeds some critical value the chain undergoes a nonequilibrium phase transition: The circular shape of the aggregate becomes unstable and the chain takes the shape of an ellipse or, in general, of a polygon. The excitation energy distribution becomes spatially nonuniform: It localizes in such places where the chain is more flat. The weak interaction of the chain with a flat surface restricts the dynamics to a flat manifold.Y.B.G. acknowledges partial financial support from a special program of the National Academy of Sciences of Ukraine, and is thankful to the Department of Applied Mathematics and Computer Science and the Department of Physics, Technical University of Denmark as well as the University of Seville for hospitality. J.F.R.A acknowledges Grant No. 2011/FQM-280 from CEICE, Junta de Andalucia Spain. J.F.R.A. and V.J.S.-M. acknowledge financial support from Project No. FIS2015-65998-C2-2-P from MINECO, Spain.Gaididei, YB.; Archilla, JFR.; Sánchez Morcillo, VJ.; Gorria, C. (2016). Energy localization and shape transformations in semiflexible polymer rings. Physical Review E. 93(6):062227-1-062227-9. https://doi.org/10.1103/PhysRevE.93.062227S062227-1062227-993

Elimination of trace organics in an MBR/RO system for water reuse

An intensive programme for detection of trace organics was performed in a membrane bioreactor (MBR) plant in Almuñécar (south of Spain) over 1 year. The compounds investigated included 15 pharmaceutically active compounds, 12 polycyclic aromatic hydrocarbons and eight other compounds (nonylphenols, linear alkylbenzene sulphonates and phthalates). The MBR operated with two lines in parallel using a hollow fibre and a flat sheet membrane respectively. Additionally, a reverse osmosis (RO) plant treated the MBR permeate over 1 month and the elimination of trace organics by the MBR/ RO system was assessed. The elimination efficiency of trace organics by the MBR was similar to that found in a conventional activated sludge plant treating the same influent. The concentration of trace organics was reduced after the MBR to a great extent and no significant differences were found between the two lines operating in parallel. The elimination efficiency increased up to 80–100% after passing the RO system. The results indicated that the MBR effluent reached the standard required by the Spanish Royal Decree for Water Reuse and can therefore be reused for multiple purposes, but advanced treatment like RO is necessary when the highest effluent quality is required

Two and three-dimensional oscillons in nonlinear Faraday resonance

We study 2D and 3D localised oscillating patterns in a simple model system exhibiting nonlinear Faraday resonance. The corresponding amplitude equation is shown to have exact soliton solutions which are found to be always unstable in 3D. On the contrary, the 2D solitons are shown to be stable in a certain parameter range; hence the damping and parametric driving are capable of suppressing the nonlinear blowup and dispersive decay of solitons in two dimensions. The negative feedback loop occurs via the enslaving of the soliton's phase, coupled to the driver, to its amplitude and width.Comment: 4 pages; 1 figur

Formation of high-order acoustic Bessel beams by spiral diffraction gratings

The formation of high-order Bessel beams by a passive acoustic device consisting of an Archimedes' spiral diffraction grating is theoretically, numerically, and experimentally reported in this paper. These beams are propagation-invariant solutions of the Helmholtz equation and are characterized by an azimuthal variation of the phase along its annular spectrum producing an acoustic vortex in the near field. In our system, the scattering of plane acoustic waves by the spiral grating leads to the formation of the acoustic vortex with zero pressure on axis and the angular phase dislocations characterized by the spiral geometry. The order of the generated Bessel beam and, as a consequence, the size of the generated vortex can be fixed by the number of arms in the spiral diffraction grating. The obtained results allow for obtaining Bessel beams with controllable vorticity by a passive device, which has potential applications in low-cost acoustic tweezers and acoustic radiation force devices.We acknowledge financial support from MINECO of the Spanish Government under Grants No. MTM2012-36740-C02-02, No. FIS2015-65998-C2-1-P, and No. FIS2015-65998-C2-2-P. N.J. acknowledges financial support from PAID-2011 Universitat Politecnica de Valencia.Jimenez, N.; Picó Vila, R.; Sánchez Morcillo, VJ.; Romero García, V.; García-Raffi, LM.; Staliünas, K. (2016). Formation of high-order acoustic Bessel beams by spiral diffraction gratings. Physical Review E. 94(5). doi:10.1103/PhysRevE.94.053004S05300494

Efecto de la pre-digestión del sustrato sobre la fermentación in vitro en conejos

Los trabajos de fermentacion realizados en conejos empleando la tecnica de produccion de gas in vitro desarrollada por Menke et al. (1979) presentan grandes variaciones en lo que se refiere a los inoculos utilizados, el procesado de los sustratos, la relacion inoculo/sustrato y los modelos matematicos de ajuste. En muchos trabajos, los sustratos solo son molidos (Calabro et al., 1999; Bovera et al., 2006), mientras que en otros se utiliza el residuo insoluble procedente de una pre-digestion in vitro donde se Simula la digestion del estomago e intestino delgado (Bindelle et a/. 2007; Rodriguez-Romero et al., 2011). Sin embargo, al estudiar la fermentacion de alimentos fibrosos seria interesante conservar en la muestra la fraccion de la fibra que se solubiliza en el intestino delgado (Abad-Guaman et al., 2015). Por otra parte, en conejos se ha observado que el nivel y tipo de fibra de la dieta de los donantes influye sobre la fermentacion in vitro (Rodriguez-Romero et al., 2011). El presente trabajo compara la fermentacion in vitro de diferentes sustratos cuando se realiza una pre-digesti6n o se incuba directamente el sustrato utilizando cecotrofos procedentes de gazapos alimentados con dos niveles de fibra soluble (FS)

Analysis of noise temperature sensitivity for the design of a broadband thermal noise primary standard

A broadband primary standard for thermal noise measurements is presented and its thermal and electromagnetic behaviour is analysed by means of a novel hybrid analytical?numerical simulation methodology. The standard consists of a broadband termination connected to a 3.5mm coaxial airline partially immersed in liquid nitrogen and is designed in order to obtain a low reflectivity and a low uncertainty in the noise temperature. A detailed sensitivity analysis is made in order to highlight the critical characteristics that mostly affect the uncertainty in the noise temperature, and also to determine the manufacturing and operation tolerances for a proper performance in the range 10MHz to 26.5 GHz. Aspects such as the thermal bead design, the level of liquid nitrogen or the uncertainties associated with the temperatures, the physical properties of the materials in the standard and the simulation techniques are discussed

Methodology for developing an advanced communications system for the Deaf in a new domain

A methodology for developing an advanced communications system for the Deaf in a new domain is presented in this paper. This methodology is a user-centred design approach consisting of four main steps: requirement analysis, parallel corpus generation, technology adaptation to the new domain, and finally, system evaluation. During the requirement analysis, both the user and technical requirements are evaluated and defined. For generating the parallel corpus, it is necessary to collect Spanish sentences in the new domain and translate them into LSE (Lengua de Signos Española: Spanish Sign Language). LSE is represented by glosses and using video recordings. This corpus is used for training the two main modules of the advanced communications system to the new domain: the spoken Spanish into the LSE translation module and the Spanish generation from the LSE module. The main aspects to be generated are the vocabularies for both languages (Spanish words and signs), and the knowledge for translating in both directions. Finally, the field evaluation is carried out with deaf people using the advanced communications system to interact with hearing people in several scenarios. In this evaluation, the paper proposes several objective and subjective measurements for evaluating the performance. In this paper, the new considered domain is about dialogues in a hotel reception. Using this methodology, the system was developed in several months, obtaining very good performance: good translation rates (10% Sign Error Rate) with small processing times, allowing face-to-face dialogues