2010 7th International Conference on the European Energy Market, 2010
The main objective of this p a p er is to p resent the p reliminary results obtained within the S... more The main objective of this p a p er is to p resent the p reliminary results obtained within the SUSPLAN EU Projece, regarding the integration of increasing levels of Renewable Energy Sources (RES) into the future S p anish energy system. Firstly, the o p timal ex p ansion of the S p anish electricity generation ca p acity from 2020 to 2050 is determined for four different storylines. Then, for each one of these storylines, a detailed analysis of the p ower system o p eration is p erformed for the years of 2020 and 2050. Two electricity models are used for that p ur p ose: i) a long term generation ex p ansion model, and ii) a medium-term system o p erational model. The results obtained showed that a high amount of RES generation could be integrated into the future S p anish p ower system but this should be accom p anied with flexible generation and storage units for ensuring a secure system o p eration.
Abstract. Net flow of water driven with an array of asymmetric pairs of microelectrodes subjected... more Abstract. Net flow of water driven with an array of asymmetric pairs of microelectrodes subjected to an ac electric potential has recently been reported. The oscillating electric field interacts with the oscillating induced charge in the diffuse double layer on the electrodes. A steady electroosmotic velocity distribution on top of the electrodes is then originated. Net fluid flow is produced because the slip velocity distribution is anisotropic. This work presents a theoretical analysis of the pumping phenomena and observations of experimental ...
Inhalable medications for patients with asthma and chronic obstructive pulmonary disease (COPD) c... more Inhalable medications for patients with asthma and chronic obstructive pulmonary disease (COPD) can be confusing even for health care professionals because of the multitude of available devices each with different operating principles. Dry powder inhalers (DPI) are a valuable option for almost all of the patients with asthma or COPD. Based on recorded patient inspiratory profiles, the peak inspiratory flow requirement of 30 L min-1 of high-resistance devices does not usually pose any practical limitations for the patients. Suboptimal adherence and errors in device handling are common and require continuous checking and patient education in order to avoid these pitfalls of all inhalation therapy. The aim of this opinion paper is to describe the working principles of DPIs and to summarise their key properties in order to help prescribing the correct inhaler for each patient.
We have recently identified, using two inbred rat strains (Lewis and SHR), the first two loci for... more We have recently identified, using two inbred rat strains (Lewis and SHR), the first two loci for an emotionality-related behavior in rats (locomotion in the central area of the open field test). Aiming to develop an alternative genetic model that will help to corroborate the existence of these loci and that could serve as a tool in the study of anxiety, we have started breeding two new rat lines. From a highly heterogeneous population, we have selectively bred rats for four generations with high and low scores for central locomotion in the open field. At the fourth generation, the new outbred lines differed from each other for the selected trait by as much as threefold. At each generation, all rats were also tested in the elevated plus maze and the black and white box, with the two lines differing significantly also in these two models of anxiety. These results suggest that behavioral measures from different tests of emotionality/anxiety are, at least in part, genetically related. They also indicate that this newly developed genetic model (herein named Floripa H and L rat lines) may be useful in the study of anxiety, as well as serving as a tool to test the existence/significance of the two aforementioned loci putatively associated with emotionality.
Dielectric Liquids, 2008. ICDL 2008. IEEE International Conference on, 2008
We analyze the AC electro-osmotic motion of a 1:1 aqueous solution, taking into account the diffe... more We analyze the AC electro-osmotic motion of a 1:1 aqueous solution, taking into account the difference in mobilities and diffusion coefficients between positive and negative ions. This model serves to understand the behavior of common systems as a solution of NaCl in water. We pay special attention to two cases. First, the case of slightly different mobilities, that can model a KCl solution. Second, the case of a strongly asymmetric solution, with an almost vanishing mobility, applicable to the case of a salt where the negative ion is much more massive than the positive one. For all the cases, we perform the mathematical description and linear analysis of the problem, in order to establish the dependence of the induced velocity with the frequency, wavelength and amplitude of the applied voltage.
IEEE International Conference on Dielectric Liquids, 2005. ICDL 2005.
Abstract Steady motion of aqueous solutions can be produced through ac electro-osmosis, due to th... more Abstract Steady motion of aqueous solutions can be produced through ac electro-osmosis, due to the coupling between ac fields and the induced charge at the double layer close to microelectrodes. Continuous unidirectional fluid motion can be obtained when the solution is placed on top of an array of microelectrodes subjected to a travelling wave potential. In this paper we consider a simple model, consisting of a single mode travelling wave. To describe the double layer we use the nonlinear Gouy-Chapman model. A numerical ...
Lactic acid bacteria are important components in the manufacture of fermented food products from ... more Lactic acid bacteria are important components in the manufacture of fermented food products from raw material such as milk, meat or vegetables. In particular, Lactococcus lactis plays a central role in the dairy industry because of its widespread use in starter cultures. When grown on glucose or lactose, L. lactis produces mainly lactate (homolactic fermentation), which provides a characteristic acidic flavour and contributes to the preservation of fermented foods.
The usefulness in control theory of the geometric theory of motion on Lie groups and homogeneous ... more The usefulness in control theory of the geometric theory of motion on Lie groups and homogeneous spaces will be shown. We quickly review some recent tesults concerning two methods to deal with these systems, namely, a generalization of the method pmpoaed by Wei and Norman for linear systems, and a reduction procedure. This last method allows us to reduce the equation on a Lie group G to that on a subgroup H, provided a particukr solution of an associated problem in G/H is known. These methods are shown to be very appmpriate to deal with control systems on Lie groups and homogeneous spaces, thtough the specific examples of the planar rigid body with two oscillators and the front-wheel driven kinematic car. Keywnrvlsr Drift-free control systems, Wei-Norman method, motion in Lie groups and homogeneous spaces, reduction.
Throughout the world, the electricity industry is currently undergoing significant restructuring ... more Throughout the world, the electricity industry is currently undergoing significant restructuring toward deregulation and competition. Under this new framework, electric firms assume more risk, and are more responsible for their own decisions. Utilities need original models that fulfil these new requirements. This paper presents a novel conceptual approach to modeling the newly deregulated power markets. It combines powerful traditional tools related to the detailed system operation with techniques for modeling economic market equilibria. The proposed approach models the competitive behavior of the electric firms by incorporating a set of constraints, namely the equilibrium constraints, into a traditional production cost model. These constraints reproduce the first order optimality conditions of the strategic companies. Thus the approach achieves a profit maximization objective while keeping the system operation details. This model has been implemented in GAMS. An application to a sample case study is also presented.
The ac electric fields longitudinally tangential to a dielectric liquid column are able to excite... more The ac electric fields longitudinally tangential to a dielectric liquid column are able to excite capillary waves on the cylindrical surface. The phenomenon is theoretically predicted using a Lagrangian formulation of the dynamics of small amplitude perturbations of the free surface. As in the dc case, dielectric forces tend to stabilize those perturbations affected by the capillary instability, but if the field is periodic parametric resonance takes place for perturbations of shorter wavelength, otherwise stable with dc fields. A detailed description ...
In this work, we extend previous analyses of ac electro-osmosis to account for the combined actio... more In this work, we extend previous analyses of ac electro-osmosis to account for the combined action of two experimentally relevant effects: ͑i͒ Faradaic currents from electrochemical reactions at the electrodes and ͑ii͒ differences in ion mobilities of the electrolyte. In previous works, the ac electro-osmotic motion has been analyzed theoretically under the assumption that only forces in the diffuse ͑Debye͒ layer are relevant. Here, we first show that if the ion mobilities of a 1-1 aqueous solution are different, the charged zone expands from the Debye layer to include the diffusion layer. We later include the Faradaic currents and, as an attempt to explore both factors simultaneously, we perform a thin-layer, low-frequency, linear analysis of the system. Finally, the model is applied to the case of an electrolyte actuated by a traveling-wave signal. A steady liquid motion in opposite direction to the applied signal is predicted for some ranges of the parameters. This could serve as a partial explanation for the observed flow reversal in some experiments.
Abstract In this paper the concept of trapping biological nanoparticles, by utilizing Dielectroph... more Abstract In this paper the concept of trapping biological nanoparticles, by utilizing Dielectrophoresis (DEP), is investigated in a system of parallel electrode arrays. The method is analyzed using a Smoluchowski equation that describes the time evolution of the concentration of the particles.
1-Substituted 1-(2,2-diphenylvinyl)cyclopropanes with electron-accepting groups at C1 undergo a n... more 1-Substituted 1-(2,2-diphenylvinyl)cyclopropanes with electron-accepting groups at C1 undergo a novel rearrangement to benzocycloheptenes on triplet-sensitized irradiation. In some instances competition between rearrangement to cyclopentenes and formation of cycloheptenes takes place. When electron-acceptor groups are not present at C1, conventional ring opening to cyclopentenes occurs exclusively. A mechanism involving intramolecular SET from the diphenylvinyl unit to the electron-acceptor group is proposed for this novel photoreaction.
Ac electrokinetics is concerned with the study of the movement and behaviour of particles in susp... more Ac electrokinetics is concerned with the study of the movement and behaviour of particles in suspension when they are subjected to ac electrical fields. The development of new microfabricated electrode structures has meant that particles down to the size of macromolecules have been manipulated, but on this scale forces other than electrokinetic affect particles behaviour. The high electrical fields, which are required to produce sufficient force to move a particle, result in heat dissipation in the medium. This in turn produces thermal gradients, which may give rise to fluid motion through buoyancy, and electrothermal forces. In this paper, the frequency dependency and magnitude of electrothermally induced fluid flow are discussed. A new type of fluid flow is identified for low frequencies (up to 500 kHz). Our preliminary observations indicate that it has its origin in the action of a tangential electrical field on the diffuse double layer of the microfabricated electrodes. The effects of Brownian motion, diffusion and the buoyancy force are discussed in the context of the controlled manipulation of sub-micrometre particles. The orders of magnitude of the various forces experienced by a sub-micrometre latex particle in a model electrode structure are calculated. The results are compared with experiment and the relative influence of each type of force on the overall behaviour of particles is described.
Electrothermal motion in an aqueous solution arises from the action of an electric field on inhom... more Electrothermal motion in an aqueous solution arises from the action of an electric field on inhomogeneities in the liquid induced by temperature gradients. The temperature field can be produced by the applied electric field through Joule heating, or caused by external sources, such as strong illumination. Electrothermal flows in microsystems are usually observed at applied signal frequencies around 1 MHz and voltages around 10 V. In this work, we present self-similar solutions for the motion of an aqueous solution in a constant temperature gradient placed on top of: (a) two coplanar electrodes subjected to an a.c. potential difference, and (b) four coplanar electrodes subjected to a four-phase a.c. signal, generating a rotating field. The first case produces two-dimensional rolls whereas the second case produces a liquid whirl. Finally, we present experimental results of electrothermal liquid flows generated by alternating and rotating electric fields under strong illumination, and these experiments are compared to the analytical solutions. The induced rotating flow could be used in the mixing of analytes and of liquids in microsystems.
Finite-amplitude bifurcation diagrams of axisymmetric liquid bridges anchored between two plane p... more Finite-amplitude bifurcation diagrams of axisymmetric liquid bridges anchored between two plane parallel electrodes subjected to a potential difference and in the presence of an axial gravity field are found by solving simultaneously the Laplace equation for the electric potential and the Young-Laplace equation for the interface by means of the Galerkinlfinite element method. Results show the strong stabilizing effect of the electric field, which plays a role somewhat similar to the inverse of the slenderness. It is also shown that the electric ...
A temporal, linear, modal stability analysis is presented for conducting liquid jets in air subje... more A temporal, linear, modal stability analysis is presented for conducting liquid jets in air subjected to time periodic electric fields. The field is originated by a mixed ac-dc potential difference between the jet and a long coaxial cylindrical electrode. As a result of the Lagrange function formalism a governing equation for the time dependent amplitude of deformation is obtained. Slightly viscous liquids may be also described by the model. The stability is obtained by inspection of the Floquet exponents of the solutions. We extend ...
2010 7th International Conference on the European Energy Market, 2010
The main objective of this p a p er is to p resent the p reliminary results obtained within the S... more The main objective of this p a p er is to p resent the p reliminary results obtained within the SUSPLAN EU Projece, regarding the integration of increasing levels of Renewable Energy Sources (RES) into the future S p anish energy system. Firstly, the o p timal ex p ansion of the S p anish electricity generation ca p acity from 2020 to 2050 is determined for four different storylines. Then, for each one of these storylines, a detailed analysis of the p ower system o p eration is p erformed for the years of 2020 and 2050. Two electricity models are used for that p ur p ose: i) a long term generation ex p ansion model, and ii) a medium-term system o p erational model. The results obtained showed that a high amount of RES generation could be integrated into the future S p anish p ower system but this should be accom p anied with flexible generation and storage units for ensuring a secure system o p eration.
Abstract. Net flow of water driven with an array of asymmetric pairs of microelectrodes subjected... more Abstract. Net flow of water driven with an array of asymmetric pairs of microelectrodes subjected to an ac electric potential has recently been reported. The oscillating electric field interacts with the oscillating induced charge in the diffuse double layer on the electrodes. A steady electroosmotic velocity distribution on top of the electrodes is then originated. Net fluid flow is produced because the slip velocity distribution is anisotropic. This work presents a theoretical analysis of the pumping phenomena and observations of experimental ...
Inhalable medications for patients with asthma and chronic obstructive pulmonary disease (COPD) c... more Inhalable medications for patients with asthma and chronic obstructive pulmonary disease (COPD) can be confusing even for health care professionals because of the multitude of available devices each with different operating principles. Dry powder inhalers (DPI) are a valuable option for almost all of the patients with asthma or COPD. Based on recorded patient inspiratory profiles, the peak inspiratory flow requirement of 30 L min-1 of high-resistance devices does not usually pose any practical limitations for the patients. Suboptimal adherence and errors in device handling are common and require continuous checking and patient education in order to avoid these pitfalls of all inhalation therapy. The aim of this opinion paper is to describe the working principles of DPIs and to summarise their key properties in order to help prescribing the correct inhaler for each patient.
We have recently identified, using two inbred rat strains (Lewis and SHR), the first two loci for... more We have recently identified, using two inbred rat strains (Lewis and SHR), the first two loci for an emotionality-related behavior in rats (locomotion in the central area of the open field test). Aiming to develop an alternative genetic model that will help to corroborate the existence of these loci and that could serve as a tool in the study of anxiety, we have started breeding two new rat lines. From a highly heterogeneous population, we have selectively bred rats for four generations with high and low scores for central locomotion in the open field. At the fourth generation, the new outbred lines differed from each other for the selected trait by as much as threefold. At each generation, all rats were also tested in the elevated plus maze and the black and white box, with the two lines differing significantly also in these two models of anxiety. These results suggest that behavioral measures from different tests of emotionality/anxiety are, at least in part, genetically related. They also indicate that this newly developed genetic model (herein named Floripa H and L rat lines) may be useful in the study of anxiety, as well as serving as a tool to test the existence/significance of the two aforementioned loci putatively associated with emotionality.
Dielectric Liquids, 2008. ICDL 2008. IEEE International Conference on, 2008
We analyze the AC electro-osmotic motion of a 1:1 aqueous solution, taking into account the diffe... more We analyze the AC electro-osmotic motion of a 1:1 aqueous solution, taking into account the difference in mobilities and diffusion coefficients between positive and negative ions. This model serves to understand the behavior of common systems as a solution of NaCl in water. We pay special attention to two cases. First, the case of slightly different mobilities, that can model a KCl solution. Second, the case of a strongly asymmetric solution, with an almost vanishing mobility, applicable to the case of a salt where the negative ion is much more massive than the positive one. For all the cases, we perform the mathematical description and linear analysis of the problem, in order to establish the dependence of the induced velocity with the frequency, wavelength and amplitude of the applied voltage.
IEEE International Conference on Dielectric Liquids, 2005. ICDL 2005.
Abstract Steady motion of aqueous solutions can be produced through ac electro-osmosis, due to th... more Abstract Steady motion of aqueous solutions can be produced through ac electro-osmosis, due to the coupling between ac fields and the induced charge at the double layer close to microelectrodes. Continuous unidirectional fluid motion can be obtained when the solution is placed on top of an array of microelectrodes subjected to a travelling wave potential. In this paper we consider a simple model, consisting of a single mode travelling wave. To describe the double layer we use the nonlinear Gouy-Chapman model. A numerical ...
Lactic acid bacteria are important components in the manufacture of fermented food products from ... more Lactic acid bacteria are important components in the manufacture of fermented food products from raw material such as milk, meat or vegetables. In particular, Lactococcus lactis plays a central role in the dairy industry because of its widespread use in starter cultures. When grown on glucose or lactose, L. lactis produces mainly lactate (homolactic fermentation), which provides a characteristic acidic flavour and contributes to the preservation of fermented foods.
The usefulness in control theory of the geometric theory of motion on Lie groups and homogeneous ... more The usefulness in control theory of the geometric theory of motion on Lie groups and homogeneous spaces will be shown. We quickly review some recent tesults concerning two methods to deal with these systems, namely, a generalization of the method pmpoaed by Wei and Norman for linear systems, and a reduction procedure. This last method allows us to reduce the equation on a Lie group G to that on a subgroup H, provided a particukr solution of an associated problem in G/H is known. These methods are shown to be very appmpriate to deal with control systems on Lie groups and homogeneous spaces, thtough the specific examples of the planar rigid body with two oscillators and the front-wheel driven kinematic car. Keywnrvlsr Drift-free control systems, Wei-Norman method, motion in Lie groups and homogeneous spaces, reduction.
Throughout the world, the electricity industry is currently undergoing significant restructuring ... more Throughout the world, the electricity industry is currently undergoing significant restructuring toward deregulation and competition. Under this new framework, electric firms assume more risk, and are more responsible for their own decisions. Utilities need original models that fulfil these new requirements. This paper presents a novel conceptual approach to modeling the newly deregulated power markets. It combines powerful traditional tools related to the detailed system operation with techniques for modeling economic market equilibria. The proposed approach models the competitive behavior of the electric firms by incorporating a set of constraints, namely the equilibrium constraints, into a traditional production cost model. These constraints reproduce the first order optimality conditions of the strategic companies. Thus the approach achieves a profit maximization objective while keeping the system operation details. This model has been implemented in GAMS. An application to a sample case study is also presented.
The ac electric fields longitudinally tangential to a dielectric liquid column are able to excite... more The ac electric fields longitudinally tangential to a dielectric liquid column are able to excite capillary waves on the cylindrical surface. The phenomenon is theoretically predicted using a Lagrangian formulation of the dynamics of small amplitude perturbations of the free surface. As in the dc case, dielectric forces tend to stabilize those perturbations affected by the capillary instability, but if the field is periodic parametric resonance takes place for perturbations of shorter wavelength, otherwise stable with dc fields. A detailed description ...
In this work, we extend previous analyses of ac electro-osmosis to account for the combined actio... more In this work, we extend previous analyses of ac electro-osmosis to account for the combined action of two experimentally relevant effects: ͑i͒ Faradaic currents from electrochemical reactions at the electrodes and ͑ii͒ differences in ion mobilities of the electrolyte. In previous works, the ac electro-osmotic motion has been analyzed theoretically under the assumption that only forces in the diffuse ͑Debye͒ layer are relevant. Here, we first show that if the ion mobilities of a 1-1 aqueous solution are different, the charged zone expands from the Debye layer to include the diffusion layer. We later include the Faradaic currents and, as an attempt to explore both factors simultaneously, we perform a thin-layer, low-frequency, linear analysis of the system. Finally, the model is applied to the case of an electrolyte actuated by a traveling-wave signal. A steady liquid motion in opposite direction to the applied signal is predicted for some ranges of the parameters. This could serve as a partial explanation for the observed flow reversal in some experiments.
Abstract In this paper the concept of trapping biological nanoparticles, by utilizing Dielectroph... more Abstract In this paper the concept of trapping biological nanoparticles, by utilizing Dielectrophoresis (DEP), is investigated in a system of parallel electrode arrays. The method is analyzed using a Smoluchowski equation that describes the time evolution of the concentration of the particles.
1-Substituted 1-(2,2-diphenylvinyl)cyclopropanes with electron-accepting groups at C1 undergo a n... more 1-Substituted 1-(2,2-diphenylvinyl)cyclopropanes with electron-accepting groups at C1 undergo a novel rearrangement to benzocycloheptenes on triplet-sensitized irradiation. In some instances competition between rearrangement to cyclopentenes and formation of cycloheptenes takes place. When electron-acceptor groups are not present at C1, conventional ring opening to cyclopentenes occurs exclusively. A mechanism involving intramolecular SET from the diphenylvinyl unit to the electron-acceptor group is proposed for this novel photoreaction.
Ac electrokinetics is concerned with the study of the movement and behaviour of particles in susp... more Ac electrokinetics is concerned with the study of the movement and behaviour of particles in suspension when they are subjected to ac electrical fields. The development of new microfabricated electrode structures has meant that particles down to the size of macromolecules have been manipulated, but on this scale forces other than electrokinetic affect particles behaviour. The high electrical fields, which are required to produce sufficient force to move a particle, result in heat dissipation in the medium. This in turn produces thermal gradients, which may give rise to fluid motion through buoyancy, and electrothermal forces. In this paper, the frequency dependency and magnitude of electrothermally induced fluid flow are discussed. A new type of fluid flow is identified for low frequencies (up to 500 kHz). Our preliminary observations indicate that it has its origin in the action of a tangential electrical field on the diffuse double layer of the microfabricated electrodes. The effects of Brownian motion, diffusion and the buoyancy force are discussed in the context of the controlled manipulation of sub-micrometre particles. The orders of magnitude of the various forces experienced by a sub-micrometre latex particle in a model electrode structure are calculated. The results are compared with experiment and the relative influence of each type of force on the overall behaviour of particles is described.
Electrothermal motion in an aqueous solution arises from the action of an electric field on inhom... more Electrothermal motion in an aqueous solution arises from the action of an electric field on inhomogeneities in the liquid induced by temperature gradients. The temperature field can be produced by the applied electric field through Joule heating, or caused by external sources, such as strong illumination. Electrothermal flows in microsystems are usually observed at applied signal frequencies around 1 MHz and voltages around 10 V. In this work, we present self-similar solutions for the motion of an aqueous solution in a constant temperature gradient placed on top of: (a) two coplanar electrodes subjected to an a.c. potential difference, and (b) four coplanar electrodes subjected to a four-phase a.c. signal, generating a rotating field. The first case produces two-dimensional rolls whereas the second case produces a liquid whirl. Finally, we present experimental results of electrothermal liquid flows generated by alternating and rotating electric fields under strong illumination, and these experiments are compared to the analytical solutions. The induced rotating flow could be used in the mixing of analytes and of liquids in microsystems.
Finite-amplitude bifurcation diagrams of axisymmetric liquid bridges anchored between two plane p... more Finite-amplitude bifurcation diagrams of axisymmetric liquid bridges anchored between two plane parallel electrodes subjected to a potential difference and in the presence of an axial gravity field are found by solving simultaneously the Laplace equation for the electric potential and the Young-Laplace equation for the interface by means of the Galerkinlfinite element method. Results show the strong stabilizing effect of the electric field, which plays a role somewhat similar to the inverse of the slenderness. It is also shown that the electric ...
A temporal, linear, modal stability analysis is presented for conducting liquid jets in air subje... more A temporal, linear, modal stability analysis is presented for conducting liquid jets in air subjected to time periodic electric fields. The field is originated by a mixed ac-dc potential difference between the jet and a long coaxial cylindrical electrode. As a result of the Lagrange function formalism a governing equation for the time dependent amplitude of deformation is obtained. Slightly viscous liquids may be also described by the model. The stability is obtained by inspection of the Floquet exponents of the solutions. We extend ...
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