Análisis de la conducta matemática de estudiantes desde modelos económicos a la teoría de las situaciones didácticas

En este póster se presenta un estudio cuyo objetivo es interpretar modelos económicos (Morton, 1971; Elster, 1989; Carmona, 1997; Bueno, 2004), concretamente los que implican “elección”, “toma de decisiones” y “teoría de juegos”, para analizar la conducta matemática de los estudiantes cuando resuelven problemas en el aula y establecer la relación entre dichos modelos

Effect of the impurities O2 or NO present in non-purified flue gas from oxy-fuel combustion processes for carbon capture and storage technology

CO2/impurities cocapture in CCS technology allows reducing the purification costs and avoiding the emission of pollutants into the atmosphere. The viability of the transport by pipeline and the geological storage of the non-purified flue gas from oxy-fuel combustion of biomass and other processes, keeping the impurities O2 or NO in the stream along with CO2, is assessed considering thermodynamic and hydraulic aspects. For this, we experimentally determined, under CCS conditions, the density, vapor-liquid equilibrium, and speed of sound of three CO2 + O2 and CO2 + NO mixtures as binary models of the gas, and we calculated their Joule-Thomson coefficients from the experimental data. Additionally, we compared the values calculated for the determined properties using the equations of state EOS-CG, GERG-2008 and PC-SAFT to our results of CO2 + O2, validating all three equations for this system. For the CO2 + NO mixtures, only PC-SAFT could be applied, which was also validated using the parameters obtained in this work. Finally, we calculated several selected CCS parameters from our data and concluded that both O2 and NO have negative effects on the transport and storage steps of this technology, which are negligible in the case of NO with the investigated concentrations

Influence of methane and carbon monoxide in the volumetric behaviour of the anthropogenic CO2: Experimental data and modelling in the critical region

Density measurements of the systems CO 2 + CH 4 at T = 304.21 K and CO 2 + CO at T = 304.21 and 308.15 K were carried out at pressures and compositions of interest in the process of transport and storage of CO 2 (CCS technology): P = 0.1 to 20 MPa, and xCO 2 ≥0.97. From the experimental P––T –xCO 2 data, we have studied the dependence of the isothermal compressibility, the excess molar volume, and the par- tial molar volume of the solute with composition, pressure and temperature within the critical region. We have modelled the volumetric behaviour of these systems with Peng–Robinson, PC-SAFT and GERG Equations of State, thus validating these equations under the conditions considered. Furthermore, we have confirmed the weakly attractive behaviour of these systems by performing a study of the interac- tions between solvent molecules, CO 2 , and those of the solute, CO or CH 4 , using the Krichevskii Function concept and the Kirkwood–Buff Theory. Finally, we have quantified the influence of small amounts of CH 4 and CO in the transport of anthropogenic CO 2 through several normalized parameters, related to the design and operation of the fluid transport process

Comparison of charge modulations in La1.875_{1.875}Ba0.125_{0.125}CuO4_4 and YBa2_2Cu3_3O6.6_{6.6}

A charge modulation has recently been reported in (Y,Nd)Ba$_2$Cu$_3$O$_{6+x}$ [Ghiringhelli {\em et al.} Science 337, 821 (2013)]. Here we report Cu $L_3$ edge soft x-ray scattering studies comparing the lattice modulation associated with the charge modulation in YBa$_2$Cu$_3$O$_{6.6}$ with that associated with the well known charge and spin stripe order in La$_{1.875}$Ba$_{0.125}$CuO$_4$. We find that the correlation length in the CuO$_2$ plane is isotropic in both cases, and is $259 \pm 9$ \AA for La$_{1.875}$Ba$_{0.125}$CuO$_4$ and $55 \pm 15$ \AA for YBa$_2$Cu$_3$O$_{6.6}$. Assuming weak inter-planar correlations of the charge ordering in both compounds, we conclude that the order parameters of the lattice modulations in La$_{1.875}$Ba$_{0.125}$CuO$_4$ and YBa$_2$Cu$_3$O$_{6.6}$ are of the same order of magnitude.Comment: 3 pages, 2 figure

High-pressure speed of sound in pure CO2 and in CO2 with SO2 as an impurity using methanol as a doping agent

Reliable speed of sound, c, values in CO2- rich mixtures and pure CO2 are required for carbon capture and storage (CCS) technology but are difficult to determine, particularly at relatively high frequencies. We tested the suitability of methanol as doping agent to obtain accurate c values in CCS systems at 5 MHz. We measured c in seven CO2-rich, CO2 + methanol mixtures between 263.15 and 323.15 K and up to 196.30 MPa, and we extrapolated the values to obtain c in pure CO2. Additionally, we measured c from 263.15 to 373.19 K and up to 190.10 MPa in two CO2-rich, CO2 + SO2 mixtures with the same SO2 composition, which is of interest for CCS, with one mixture doped with methanol. We compared our results for pure CO2 with the literature and the Span and Wagner equation of state (EoS). We validated the PC-SAFT EoS and the modeling with the REFPROP 9 software for the mixtures by comparing the predicted values with our experimental data under the studied conditions. We conclude that methanol is a suitable doping agent to measure c in pure CO2 and CO2-rich mixtures. For the CO2 + SO2 mixtures, the effect of methanol on the experimental values is small and negligible for modeling

¿Cuál es el perfil de los futuros profesores de matemáticas en educación secundaria?

En este póster se presenta un análisis de los programas de formación inicial docente de matemáticas en Educación Secundaria, con el objetivo de conocer el perfil profesional de los estudiantes del Máster en Formación del Profesorado (MFP) a partir de las titulaciones que dan acceso al mismo y de las condiciones de entrada a los diferentes programas en las distintas universidades españolas

Química de los cementos

En la presente comunicación se describen los resultados mas relevantes obtenidos a lo largo del tiempo en torno a algunas de las líneas de trabajo mas importantes que se desarrollan en el seno del grupo de investigación “Química del Cemento” del Instituto de Ciencias de la Construcción Eduardo Torroja (IETcc-CSIC).Edición financiada por el Ministerio de Educación y Ciencia con cargo al "Plan Nacional de I+D+I 2004-2007".Peer reviewe

Influence of SO2 on CO2 Transport by Pipeline for Carbon Capture and Storage Technology: Evaluation of CO2/SO2 Cocapture

CO2 capture and storage (CCS) is an important technology for avoiding atmospheric CO2 emissions, which are principally originated from fossil fuels combustion. Anthropogenic CO2 contains impurities that can strongly modify the properties of the stream. Several authors have shown that some of these impurities, such as SO2 present in emissions from sulfur-containing fuels, could be favorable for some steps of the process, and the possibility of cocapture has been proposed. To assess this possibility with regard to the transport stage of CCS, we determined the influence of SO2 on selected parameters of transport by pipeline (minimal operational pressure, pressure and density drops, distance between boosters, booster power, and inner diameter of the pipeline, and the Joule-Thomson coefficient). For this purpose, we obtained new and accurate experimental data for the density and vapor–liquid equilibrium of five CO2 + SO2 mixtures under conditions of interest for CCS and speed of sound data for four of them. We compared our results to those found in the literature and to the values calculated using two equations of state for their validation: perturbed-chain statistical associating fluid theory (PC-SAFT) and an extended version of equation of state for combustion gases (EOS-CG) that includes a binary model for the CO2 + SO2 mixture. Allowing for the fact that chemical effects due to the presence of SO2, such as pipeline corrosion, have not been considered, we conclude that CO2/SO2 cocapture might favor and decrease the costs of the transport step of this technology, helping to avoid emissions of a highly toxic gas to the atmosphere without high desulfuration expenses

Severe apnoea detection using speaker recognition techniques

Proceedings of the International Conference on Bio-inspired Systems and Signal Processing (BIOSIGNALS 2009)The aim of this paper is to study new possibilities of using Automatic Speaker Recognition techniques (ASR) for detection of patients with severe obstructive sleep apnoea (OSA). Early detection of severe apnoea cases can be very useful to give priority to their early treatment optimizing the expensive and timeconsuming tests of current diagnosis methods based on full overnight sleep in a hospital. This work is part of an on-going collaborative project between medical and signal processing communities to promote new research efforts on automatic OSA diagnosis through speech processing technologies applied on a carefully designed speech database of healthy subjects and apnoea patients. So far, in this contribution we present and discuss several approaches of applying generative Gaussian Mixture Models (GMMs), generally used in ASR systems, to model specific acoustic properties of continuous speech signals in different linguistic contexts reflecting discriminative physiological characteristics found in OSA patients. Finally, experimental results on the discriminative power of speaker recognition techniques adapted to severe apnoea detection are presented. These results obtain a correct classification rate of 81.25%, representing a promising result underlining the interest of this research framework and opening further perspectives for improvement using more specific speech recognition technologiesThe activities described in this paper were funded by the Spanish Ministry of Science and Technology as part of the TEC2006-13170-C02-01 project