Laboratorio de Plasmas Densos (PLADEMA)

Exposición realizada en el marco del  Encuentro del Ministerio de la Producción, Ciencia y Tecnología de la Provincia de Buenos Aires con autoridades y centros de la Comisión de Investigaciones Científicas de la Provincia de Buenos Aires. Exposiciones de los directores de los Centros de Investigación propios, asociados y vinculados

Climate change, in the framework of the Constructal Law

Here we present a simple and transparent alternative to the complex models of earth’s thermal behaviour under time-changing conditions. We show the one-to-one relationship between changes in atmospheric properties and time-dependent changes in temperature and its distribution on earth. The model accounts for convection and radiation, thermal inertia and changes in albedo (ρ) and greenhouse factor (γ). The constructal law is used as the principle that governs the evolution of fl ow confi guration on earth. The model showed that for two time-dependent scenarios, (δρ = 0.002; δγ = 0.011) and (δρ = 0.002; δγ = 0.005) the predicted equatorial and polar temperature increases and the time scales are (ΔTH = 1.16 K; ΔTL = 1.11 K; 104 years) and (0.41 K;0.41 K; 57 years), respectively. A continuous model of temperature variation was used to predict the thermal response of the Earth’s surface to changes bounded by δρ = δγ and δρ = −δγ. The poleward heat current reaches its maximum in the vicinity of 35° latitude,accounting for the position of the Ferrel cell between the Hadley and Polar Cells

The operation of VEGA/CHARA : from the scientific idea to the final products

We describe the data flow in the operation of the VEGA/CHARA instrument. After a brief summary of the main characteristics and scientific objectives of the VEGA instrument, we explain the standard procedure from the scientific idea up to the execution of the observation. Then, we describe the different steps done after the observation, from the raw data to the archives and the final products. Many tools are used and we show how the Virtual Observatory principles have been implemented for the interoperability of these software and databases.Comment: 9 pages, 3 figure

Thermochemical Heat Tranformer for Waste Heat Recovery: consideration of dynamic aspects for design

International audienceWaste Heat Recovery in the industrial sector often requires to upgrade the temperature of the heat fluxes in order to make them useful for the process. Thermochemical Heat Transformer can play a major role as they can provide high temperature lift when compared to alternative technologies. The aim of the presented work is twofold: - to identify suitable working pairs using water as working fluid taking into account three criteria: COP, temperature lift and equilibrium drop (difference of the operating temperature and pressure to their value at equilibrium) - to run a parametric study, thanks to a dynamic 2-salt/2-reactor model, to identify optimal specific heat power as a function of cycle time, working pairs and reactor heat transfer coefficient. For waste heat temperature at 90 °C and a cold source at 30 °C, the CaCl2 /H2O and Ca(NO 3)2 /H2O working pairs were identified as promising. The achieve temperature lift is as high as 90 K for a theoretical COP of 0.42. In dynamic operating, a specific heat power of 325 W/kg was found

Modelado por medio de elementos finitos móviles de la dinámica de flujos en ebullición

Se presenta un modelo numérico de un canal de ebullición en base a elementos finitos unidimensionales móviles. El modelo se basa en una aproximación nodal de Galerkin para las ecuaciones de conservación de un canal en ebullición. Entre cada nodo se proponen perfiles espaciales de entalpía, llegándose a un sistema de ecuaciones ordinarias no lineales que permiten hallar la evolución temporal de la posición de cada nodo. Se presentan varias soluciones, y se discuten las ventajas e inconvenientes que posee la utilización de un método de elementos finitos móviles para la resolución de este tipo de problemas.A numerical model of a boiling channel based in one-dimensional variable-length finite elements is presented. A Galerkin nodal approximation is used to reduce the conservation equations to a set of ordinary differential equations. Spatial enthalpy profiles are assumed between each.node, yielding a set of non-linear equations for the position of the nodes. Severa1 numerical solutions are presented and the advantages and disadvantages of the application of finite elements in this type of problems is discussed.Peer Reviewe

NUMERICAL PARAMETRIC STUDY ON CO2 CAPTURE BY INDIRECT THERMAL SWING ADSORPTION

International audiencePost-combustion CO2 capture remains one of the most-challenging issue to lower CO2 emissions of existing power plants or heavy industry installations because of strong economy and energy efficiency aspects. The major issue comes from CO2 dilution (4% for NGCC and 14% for PC) and the high flow rates to be treated. Furthermore, CO2 purity has to be higher than 95% with recovery at 90%, to match the transportation/injection requirements. The MEA absorption process remains the reference today but its energy consumption (about 3 MJ/kgCO2) and the amine consumption are still challenging drawbacks. The interest of CO2 capture by indirect TSA (Temperature Swing Adsorption) was demonstrated experimentally in a previous work. The aim of this paper is to present the results of a numerical parametric study. Two main parameters are explored: the desorption temperature (100 to 200 °C) and the purge flow rate (0.1 to 0.5 Ndm 3 .min-1). Four performance indicators are evaluated: CO2 purity, recovery, productivity and specific energy consumption. Results show that purity above 95% can be achieved. Keeping the 95% target, it is possible to achieve recovery at 81% with productivity at 57.7 gCO2/kgads.h and a specific 2 energy consumption of 3.23 MJ/kgCO2, which is about the same level than for up to date MEA processes. Comparison with other adsorption processes exhibits that this process has good potential especially since some improvements are still expected from further research

Influence of the Presence of CO2 in the Feed of an Indirect Heating TSA Process for VOC Removal

International audienceThis work deals with an experimental study of an indirect temperature swing adsorption process for VOC removal from air or for gas purification. A 1 m long and 70 mm diameter column with an internal heat exchanger has been filled with Ambersorb 600 carbonaceous adsorbent. This column is equipped with sensors to measure temperature at several points inside the bed, as well as the inlet and outlet gas concentration, pressure, temperature and mass flow. In a first step, CO2 or ethane/ dry nitrogen mixtures were used to simulate a single VOC in air, with different concentrations (350 ppm, 1% and 10%). As a first results very effective gas purification was obtained and an advantage of this process is the high pollutant concentration during the regeneration phase. Experiments were performed with various ethane/CO2 mixtures. The influence of the presence of CO2 on the ethane concentration breakthrough curves and on the ethane concentration during regeneration is reported. The IAS theory was used, as a first approach, to predict the adsorbed pollutants amount. Relatively good prediction is obtained with a maximum error in the order of 10%. An energy balance study is reported as well

A low-cost portable simulator of a domestic cat larynx for teaching endotracheal intubation

Objective: To design and construct an affordable simulator of the cat larynx for training intubation maneuvers and to share the designs for its fabrication. Study design: Research and development study. Animals: A domestic cat. Methods: The cadaver of a cat, dead by natural causes, was frozen in sternal recumbency with the neck extended and the mouth wide open. A computed tomography image was acquired and used to construct a digital three-dimensional (3D) model of the pharynx and trachea. A digitally adapted model was 3D-printed and used to generate a silicone model of these structures, which was placed within a wooden container. The quality of the simulator was assessed by 46 veterinary anesthesiologists and veterinarians with experience in tracheal intubation maneuvers, and their opinions were obtained through an anonymous questionnaire. Results: Several preliminary prototypes were assessed regarding stability, texture and cost. Finally, a silicone model of a cat larynx (LaryngoCUBE) was produced and encased in a wooden container. Results from the questionnaire showed high scores regarding anatomy, tissue texture and intubation maneuver realism, compared with the real procedure. Conclusions: and clinical relevance Use of LaryngoCUBE as a training tool may improve the skills of students and reduce the use of animals for teaching endotracheal intubation. Blueprints and computational models are provided online so that the simulator can be fully reproduced.Fil: Clausse, María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigación Veterinaria de Tandil. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigación Veterinaria de Tandil. Provincia de Buenos Aires. Gobernación. Comision de Investigaciones Científicas. Centro de Investigación Veterinaria de Tandil; ArgentinaFil: Nejamkin, Pablo. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Veterinarias. Departamento de Fisiopatología. Laboratorio de Farmacología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil; ArgentinaFil: Bulant, Carlos Alberto. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Exactas. Grupo de Plasmas Densos Magnetizados. Provincia de Buenos Aires. Gobernación. Comision de Investigaciones Científicas. Grupo de Plasmas Densos Magnetizados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil; ArgentinaFil: Genaro, Ariel. Instituto de Profesorado de Arte Tandil; ArgentinaFil: Landivar, Florencia. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Veterinarias; ArgentinaFil: del Sole, Maria Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigación Veterinaria de Tandil. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigación Veterinaria de Tandil. Provincia de Buenos Aires. Gobernación. Comision de Investigaciones Científicas. Centro de Investigación Veterinaria de Tandil; ArgentinaFil: Clausse, Alejandro. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Exactas. Grupo de Plasmas Densos Magnetizados. Provincia de Buenos Aires. Gobernación. Comision de Investigaciones Científicas. Grupo de Plasmas Densos Magnetizados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil; Argentin

A Python implementation in graphic processing unit of a lattice Boltzmann model for unstable three-dimensional flows in immersed permeable media

The implementation of a lattice Boltzmann model for three-dimensional permeable media with localized drag forces is presented. The model was previously introduced for two-dimensional geometries and follows the basics of the immersed boundary method. Permeable flows are much less stable than their counterparts in porous media and generally produce large coherent flow structures, such as vortex lines, rolls, and wakes. In addition, in permeable media, the small-scale geometry often needs to be represented to a high degree of detail in order to capture certain transport phenomena, such as micro-convection or pollination. Hence, both calculation speed and memory requirements are under strain. The present model was implemented in a graphic processing unit showing excellent performance in the calculation of stable and unstable flows in a rectangular channel partially obstructed by an array of parallel wires. In particular, the model is able to deal with small and medium spatial scales without losing the heterogeneous nature of permeable flows in the homogenization process. The algorithm to manage memory issues is described in detail, and the results of the test case for stable and unstable conditions show the capability of the method to simulate these types of flows.Fil: Boroni, Gustavo Adolfo. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Sociales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Silin, Nicolas. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Clausse, Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica; Argentin