7,863 research outputs found
Absorption and Direct Processes in Chaotic Wave Scattering
Recent results on the scattering of waves by chaotic systems with losses and
direct processes are discussed. We start by showing the results without direct
processes nor absorption. We then discuss systems with direct processes and
lossy systems separately. Finally the discussion of systems with both direct
processes and loses is given. We will see how the regimes of strong and weak
absorption are modified by the presence of the direct processes.Comment: 8 pages, 4 figures, Condensed Matter Physics (IV Mexican Meeting on
Mathematical and Experimental Physics), Edited by M. Martinez-Mares and J. A.
Moreno-Raz
Soy protein enzymatic hydrolysis and polysaccharides interactions: differential performance on kinetic adsorption at air-water interface
The objective of the work was to study the impact of soy protein hydrolysis on kinetic adsorption to the air-water interface and the effect
of polysaccharides addition. Was used soy protein (SP) and theirs hydrolysates of 2% (H1) and 5.4% (H2) degree of hydrolysis. The
polysaccharides (PS) used were a surface active one called E4M and a non-surface active one, lamda carrageenan (C). The dynamic
surface pressure of interfacial films was evaluated with a drop tensiometer. In this contribution, we have determined the kinetic
parameters of adsorption to the air-water interface which determined the penetration (Kp) and rearrangement (Kr) rates of SP, H1, H2
and PS, as well as their mixed systems. It was observed an increase of Kp and Kr when the protein were hydrolyzed (from SP to H1),
however, when degree of hydrolysis progresses to H2 the parameters decreased again. In other hand, considerable differences were not
found between these two PS studied concerning the Kp to air-water interface at these conditions. In spite of the different surface active
nature of the PS, the proteins seem to control the behavior of the protein-PS interactions. However, when Kr of mixed systems was
analyzed, the degree of hydrolysis and PS nature started to have a huge importance. Hence, it could be observed synergic or antagonic
effects on Kr of biopolymers at liquid interface depending to the degree of hydrolysis of protein analyzed and the type of PS selected.CYTED through project 105PI0274CYCYT through grant AGL2007-60045Junta de Andalucía through grant PO6-AGR-01535Universidad de Buenos Aires, Agencia Nacional de Promoción Científica y Tecnológica (PICT 2008-1901) and Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentin
Electromagnetic prompt response in an elastic wave cavity
A rapid, or prompt response, of an electromagnetic nature, is found in an
elastic wave scattering experiment. The experiment is performed with torsional
elastic waves in a quasi-one-dimensional cavity with one port, formed by a
notch grooved at a certain distance from the free end of a beam. The stationary
patterns are diminished using a passive vibration isolation system at the other
end of the beam. The measurement of the resonances is performed with
non-contact electromagnetic-acoustic transducers outside the cavity. In the
Argand plane, each resonance describes a circle over a base impedance curve
which comes from the electromagnetic components of the equipment. A model,
based on a variation of Poisson's kernel is developed. Excellent agreement
between theory and experiment is obtained.Comment: 4 pages, 5 figure
Scattering of Elastic Waves in a Quasi-one-dimensional Cavity: Theory and Experiment
We study the scattering of torsional waves through a quasi-one-dimensional
cavity both, from the experimental and theoretical points of view. The
experiment consists of an elastic rod with square cross section. In order to
form a cavity, a notch at a certain distance of one end of the rod was grooved.
To absorb the waves, at the other side of the rod, a wedge, covered by an
absorbing foam, was machined. In the theoretical description, the scattering
matrix S of the torsional waves was obtained. The distribution of S is given by
Poisson's kernel. The theoretical predictions show an excellent agreement with
the experimental results. This experiment corresponds, in quantum mechanics, to
the scattering by a delta potential, in one dimension, located at a certain
distance from an impenetrable wall
Current collection by an active spherical electrode in an unmagnetized plasma
A theoretical model for the steady-state response of anodic contactors that emit a plasma current Ii and collect electrons from a collisionless, unmagnetized plasma is
presented. The use of a (kinetic) monoenergetic population for the attracted species, well known in passive probe theory, gives both accuracy and tractability to the theory.
The monoenergetic population is proved to behave like an isentropic fluid with radial plus centripetal motion, allowing direct comparisons with ad hoc fluid models. Also, a modification of the original monoenergetic equations permits analysis of contactors operating in orbit-limited conditions. Besides that, the theory predicts that, only for plasma emissions above certain threshold current a presheath/double layer/core structure for the potential is formed (the core mode), while for emissions below that threshold, a plasma contactor behaves exactly as a positive-ion emitter with a presheath/sheath structure (the no-core mode). Ion emitters are studied as a particular case. Emphasis is placed on obtaining dimensionless charts and approximate asymptotic laws of the current-voltage characteristic
Los instrumentos de gestión de las fronteras exteriores de la Unión Europea ante los flujos migratorios masivos
El presente artículo se centra en el análisis de los mecanismos de la Unión Europea para el control de sus fronteras exteriores, a la luz de la última gran crisis migratoria y de refugiados que sufre el continente europeo, con especial referencia a la reciente creación de la Guardia Europea de Fronteras y Costas, lo que podría considerarse como una policía fronteriza común europea.This article focuses on the analysis of EU mechanisms to control its external borders, in the light of the last great migratory and refugee crisis afflicting the European continent, with special reference to the recent creation of the European Border and Coast Guard, what it could be considered as a common European border police
UV Dichroism in Vertically Aligned Nematic Displays
Vertically aligned negative nematics are employed in high-end projection applications, where extremely high light fluxes are employed. Under these conditions, the UV photochemical stability of the material becomes an issue that must be included in the characterization process of such devices. Photochemical aging tests for vertically aligned microdisplay, however, must take into account the linear dichroism shown by the liquid crystal material upon switching. In this work a method to evaluate UV linear dichroism is described. The method is included in a comparative study of the electrooptical performance of two negative nematic mixtures, one experimental and one commercial
- …