Search results for "electromagnetism"
showing 10 items of 276 documents
Influence of total solids concentration on membrane permeability in a submerged hollow-fibre anaerobic membrane bioreactor.
2012
The main aim of this work was to study the influence of the mixed liquor total solids (MLTS) concentration on membrane permeability (K 20) in a submerged anaerobic membrane bioreactor (SAnMBR) pilot plant, which is equipped with industrial hollow-fibre membranes and treats urban wastewater. This pilot plant was operated at 33°C and 70 days of SRT. Two different transmembrane fluxes (13.3 and 10 LMH) were tested with a gas sparging intensity of 0.23 Nm 3 m -2 h -1 (measured as Specific Gas Demand referred to membrane area). A linear dependence of K 20 on MLTS concentration was observed within a range of MLTS concentration from 13 to 32 g L -1 and J 20 of 10 LMH. K 20 was maintained at sustai…
Permeability properties of a three-cell type in vitro model of blood-brain barrier.
2005
We previously found that RBE4.B brain capillary endothelial cells (BCECs) form a layer with blood‐brain barrier (BBB) properties if co‐cultured with neurons for at least one week. As astrocytes are known to modulate BBB functions, we further set a culture system that included RBE4.B BCECs, neurons and astrocytes. In order to test formation of BBB, we measured the amount of (3)H‐sucrose able to cross the BCEC layer in this three‐cell type model of BBB. Herein we report that both neurons and astrocytes induce a decrease in the permeability of the BCEC layer to sucrose. These effects are synergic as if BCECs are cultured with both neurons and astrocytes for 5 days, permeability to sucrose decr…
The Action Principle in Classical Electrodynamics
2001
The main purpose of this chapter is to consider the formulation of a relativistic point particle in classical electrodynamics from the viewpoint of Lagrangian mechanics. Here, the utility of Schwinger’s action principle is illustrated by employing three different kinds of action to derive the equations of motion and the associated surface terms.
Cylindrical surface waveguide modes using a surface impedance dyadic method
1987
The fields and characteristic parameters of nonradiating modes of a dielectric-coated wire with an intervening airgap are derived using a surface impedance dyadic method. This method shows several advantages and provides a straightforward method for working out the characteristic equation, cutoff conditions, far-from-cutoff conditions and field coefficients. Important results about the hybrid nature of these modes are shown, and some of them are common to any cylindrical surface waveguide.
A New Approach to the Modeling of Anisotropic Media with the Transmission Line Matrix Method
2021
A reformulation of the Transmission Line Matrix (TLM) method is presented to model non-dispersive anisotropic media. Two TLM-based solutions to solve this problem can already be found in the literature, each one with an interesting feature. One can be considered a more conceptual approach, close to the TLM fundamentals, which identifies each TLM in Maxwell’s equations with a specific line. But this simplicity is achieved at the expense of an increase in the memory storage requirements of a general situation. The second existing solution is a more powerful and general formulation that avoids this increase in memory storage. However, it is based on signal processing techniques and considerabl…
Analytical solution for the magneto-electro-elastic bimorph beam forced vibrations problem
2009
Based on the Timoshenko beam theory and on the assumption that the electric and magnetic fields can be treated as steady, since elastic waves propagate very slowly with respect to electromagnetic ones, a general analytical solution for the transient analysis of a magneto-electro-elastic bimorph beam is obtained. General magneto-electric boundary conditions can be applied on the top and bottom surfaces of the beam, allowing us to study the response of the bilayer structure to electromagnetic stimuli. The model reveals that the magneto-electric loads enter the solution as an equivalent external bending moment per unit length and as time-dependent mechanical boundary conditions through the def…
P1082COMPARISON OF THE REMOVAL OF PROTEIN-BOUND TOXINS AND LARGE MIDDLE MOLECULES WITH HIGH-FLUX PMMA AND MEDIUM CUT-OFF DIALYZERS
2020
Abstract Background and Aims Dialytic clearance of protein-bound toxins and large middle molecules is poor by diffusive treatment and limited by high-flux hemodialysis (HD) and on-line hemodiafiltration (OL-HDF), and only a few studies have examined how to improve their removal by other extracorporeal strategies. Since 2017, there is a new generation of polymethyl methacrylate (PMMA) membranes that suppress platelet adhesion on the membrane surface improving hemocompatibility and permeability, while also maintaining adsorption properties related to conventional PMMA membranes. Expanded HD (HDx) with medium cut-off (MCO) membranes has also recently been incorporated into clinical practice an…
Rational design and modelling of f-block molecular nanomagnets
2016
Los imanes monomoleculares o moléculas imán, por sus siglas en inglés SMMs, han suscitado una gran atención en los últimos años debido a sus extraordinarias propiedades físicas. Los cristales de este tipo de moléculas se caracterizan por presentar relajación lenta de la magnetización a baja temperatura, así como curvas de histeresis magnética. Estas moléculas se encuentran entre las entidades con comportamiento magnético más complejas, mostrando fenómenos cuánticos tales como efecto túnel en la magnetización, coherencia cuántica o interferencia cuántica. Por esto, se han postulado como candidatos prometedores para el diseño de bits cuánticos (qubits) de espín en computación cuántica. La pri…
Magnetic materials based on layered double hydroxides: chemical design, processing and electrochemical applications
2018
Tras el descubrimiento del grafeno en 2004, los materiales bidimensionales han generado un interés creciente por parte de la comunidad científica que se prolonga hasta nuestros días. Junto a este material constituido por delgadas láminas de carbono, también existen materiales bidimensionales de naturaleza inorgánica entre los que predominan aquellos basados en fuerzas de van der Waals. Dicalcogenuros metálicos, fósforo negro o antimoneno son algunos de estos ejemplos. Sin embargo, también existen materiales 2D formados por láminas iónicas, donde son las fuerzas electrostáticas las que ejercen un papel fundamental en cuanto a la organización y estructura de dichos sistemas. Este es el caso d…
Environment recognition applied to particle detectors
2017
Resumen en español Introducción Los detectores de partículas son dispositivos que registran la radiación ionizante, bien de sistemas activos (rayos X, aceleradores, etc.) o bien de isótopos radiactivos. Para poder realizar medidas de precisión con estos instrumentos, es necesario modelar geométricamente el entorno, contorno o escena bajo estudio. Estas condiciones geométricas se pueden determinar de forma más o menos precisa en algunos experimentos de física de partículas/nuclear, y en algunos sistemas de imagen, como las tomografías. Sin embargo, este escenario no es necesariamente el habitual. El propósito principal de este trabajo de tesis es desarrollar técnicas e instrumentos que aport…