Las matemáticas y el diseño: el razonamiento abstracto como soporte a la actividad creativa

Introducir en clases la creatividad aumenta el interés del alumnado con las materias. Las “Matemáticas” presentan grandes dificultades para los alumnos, dado su carácter abstracto, por ello las nuevas metodologías deben orientarse a aumentar la motivación para conseguir mayor rendimiento, mejorar el proceso enseñanza-aprendizaje y potenciar la relación alumno-profesor. Nuestra experiencia combina elementos de geometría y cálculo en el diseño. Separadamente, ambos conceptos tienen definidos sus entornos, ámbitos y resultados. Se trata que el alumno aplique los elementos de geometría analítica y cálculo al diseño de espacios y/o mobiliario. El trabajo es realizado en grupos, definiendo roles específicos. Se presentan las propuestas de diseño y cálculos al profesor en (al menos dos) sesiones tutoriales obligatorias, para verificar la “viabilidad analítica” del proyecto. Fijamos una entrega previa del trabajo para emitir las recomendaciones de cara a la presentación final. Los proyectos son defendidos ante la clase y un tribunal multidisciplinar, así evaluamos las competencias generales y específicas, adquiridas por los alumnos, en todas las materias integradas en esta actividad. La calificación final tuvo en cuenta la valoración de los alumnos. Y utilizamos rúbricas para evaluar las distintas competencias. Se recogió la opinión, de los alumnos, sobre la actividad mediante un cuestionario.SIN FINANCIACIÓNNo data 2012UE

Las matemáticas en la Economía a través de los premios Nobel. Una propuesta didáctica para mejorar la motivación en el aprendizaje de las matemáticas

Diversos estudios subrayan que la motivación en el aprendizaje de las matemáticas es un factor que influye en el rendimiento académico de los alumnos. El alto número de abandonos y fracasos en la asignatura de matemáticas en el primer curso de los grados pertenecientes al área de Economía está, en gran medida, relacionado con la baja motivación que presentan los alumnos de dichas titulaciones por el estudio de esta materia. A ésta desmotivación tenemos que añadir el bajo nivel de conocimientos previos y el rechazo producido por considerar las matemáticas poco aplicables en su futuro profesional. Presentamos el desarrollo de una actividad de aprendizaje llevada a cabo en el curso 2009-2010 en la Universidad Europea de Madrid en diversos grados de la Facultad de Ciencias Sociales, cuyo objetivo fue mejorar la motivación en el aprendizaje de las matemáticas a través de ejemplos prácticos de la aplicabilidad de las matemáticas en su titulación. La actividad se realizó de forma grupal y consistió en la investigación de un premio Nobel en Economía cuyas contribuciones matemáticas fuesen especialmente relevantes. Mediante la realización de esta propuesta didáctica se consiguió, además, desarrollar diversas competencias generales como el trabajo en equipo, la planificación y la recogida, síntesis y análisis de la información, así como introducir un elemento de internacionalidad en el aula ampliando el conocimiento sobre los premios Nobel y su impacto internacional.SIN FINANCIACIÓNNo data 2010UE

Amino-Functionalized Multiwall Carbon Nanotubes as Efficient Basic Catalysts for the Formation of γ-Lactams: Synthesis of N-1-Heptenyl-2-pyrrolidinone

In this work, we prepared a series of N-functionalized carbon nanotubes by means of a process of acylation-amidation of commercial multiwall carbon nanotubes that were previously pre-oxidized with nitric acid. Three different amines, butylamine, N,N-dimethyl ethylenediamine, and ethylenediamine, were used in the process. The characterization of samples by several techniques probed the incorporation of nitrogen atoms to the carbon nanotubes, especially in the case of ethylenediamine. The solids were tested as catalysts in the synthesis of N-1-heptenyl-2-pyrrolidinone, included in the group of a γ-lactams, compounds that show important biological properties. The most active catalyst was that prepared with butylamine, which exhibited the highest SBET and Vpore values and contained an amount of nitrogen that was intermediate between that of the other two catalysts. A yield of 60% to N-1-heptenyl-2-pyrrolidinone was achieved after 3 h at 120 °C under free-solvent conditions. This catalyst could be used in four consecutive cycles without significant activity loss

Synthesis and physico-chemical properties of multi-walled carbon nanotubes doped with transition metals

In this paper we show the synthesis and characterization of multiwall carbon nanotubes (CNT) doped with different transition metals, M-CNT (with M= V, Cr, Mo, Ni). The goal is to obtain acid catalysts active for the synthesis of Fine Chemicals. Other carbonaceous materials containing those metals, in particular, carbon xerogels, were tested in the synthesis of chalcones, resulting as active catalysts [4]. The solids have been prepared by treatment of commercial multiwall carbon nanotubes with nitric acid (CNTO) and subsequent doping with the metals by ionic exchange of the corresponding salts under ultrasonic activation. The materials thus obtained were dried at 60 °C and pyrolyzed at 500 °C to decompose the salts. A reference solid without metal was also prepared (CNTOp). The analysis by different techniques shows that the doping of the CNT with the metals has been produced. Thus, FTIR-ATR spectra show the disappearing of the bands assigned to the carboxylic groups and the appearing of new bands. The TG curves in air of the pyrolyzed samples lead to a higher residue than that for CNTOp, following the V > Cr > Ni > Mo order. The thermal stability of C=C bonds of the skeleton of nanotubes functionalized with nitric acid (CNTO) increases with respect to commercial nanotubes; however, in samples doped the temperature of decomposition of nanotubes is lowered in approximately 100 °C, with respect to that of CNTOp. This fact indicates that the metallic phases contribute to the destabilization of the nanotubes, promoting their oxidation. The exception is the Mo-CNT sample, whose TG curve is not altered with respect to that for CNTOp, the final residue being almost the same for both samples. Therefore, in the case of sample containing Mo, the doping has been produced in a less extent than for the rest of metals. XRD patterns of samples show the formation of vanadium pentoxide in the V-CNT sample, whereas no crystalline phase is detected for the rest of samples, indicating a higher dispersion of the metals in the carbon nanotubes. The commercial carbon nanotubes are mesoporous solids. The oxidation causes a decrease in SBET and the pore volume due to the pore blockage by oxygenated functionalities, which are partially removed during pyrolysis. The value of the BET areas also decreases in nanotubes doped with the transition metals, due to the blockage of micropores and small mesopores by the metals.2017/UEM09Ministerio de Ciencias e Innovación CTM2014-56668-RNo data 2018UE

Molecular dynamics simulation of the adsorption of alkali metal cations on carbon nanotubes surfaces

In a previous work, we prepared multiwalled carbon nanotubes (MWCNTs) impregnated with alkali metals and when characterized by different techniques, we observed that the incorporation of Cs to the MWCNTs by impregnation with Cs acetate was produced to a lesser extent than for the rest of alkali metal (Li, Na and K) acetates. In order to explain these results, in this paper we present classical molecular dynamics (MD) simulations of alkali metal cation (Li+, Na+, K+ and Cs+) adsorption on the surface of a (6,6) CNT functionalized with carboxylate groups. We study the time evolution of the distance between the alkali cations and the CNT surface, the oxygen-cation radial distribution functions, the structure of the first hydration shell, the diffusion coefficient of the cations and the interaction energies with the CNT. We conclude that the high mobility of the Cs+ cation as well as the small electrostatic interaction with the functional groups of the CNT surface could explain its lesser adsorption, when compared with the other three alkali metal cations, agreeing with the results of the lower incorporation of Cs to the MWCNTs observed by the different characterization techniques.UEM09No data JCR 20190.341 SJR (2019) Q3, 150/372 Electronic, Optical and Magnetic MaterialsNo data IDR 2019UE

Nanotubos de carbono de pared múltiple dopados con metales alcalinotérreos con propiedades catalíticas básicas

2018/UEM21No data 2001UE

Síntesis y caracterización de nanotubos de carbono de pared múltiple dopados con metales alcalinotérreos

2017/UEM09CTM2014-56668-RNo data (2017)UE

Porous Alkaline-Earth Doped Multiwall Carbon Nanotubes with Base Catalytic Properties

Alkaline-earth doped multiwall carbon nanotubes, M-CNT (M = Mg, Ca, Sr, Ba) have been prepared by a combined method of ionic exchange and precipitation. The wide characterization of the solids by nitrogen adsorption, ATR–FTIR, thermal analysis, XRD, scanning electron microscopy, transmission electron microscopy, point of zero charge (PZC), and X-ray photoelectron spectroscopy shows that the incorporation of M to the CNTs has been successfully produced. The doping with the alkaline-earth cations causes a decrease in the SBET value of the raw material, mainly due to the blockage of mesopores by the metal carbonate phase formed in most of cases. This metallic phase also contributes to the destabilization of the nanotubes by promoting their oxidation. According to PZC values, the acid character of oxidized CNTs changes to basic for the M-CNT series, Mg-CNT showing the highest PZC value. The basic properties of the catalysts have been tested in the C–C bond forming reaction of Knoevenagel, by carrying out the condensation of ethyl cyanoacetate with benzaldehyde or 4-methoxybenzaldehyde.Sin financiación2.482 JCR (2019) Q3, 91/159 Chemistry, Physical0.567 SJR (2019) Q2, 139/471 Chemistry (miscellaneous)No data IDR 2019UE

Fe-Cu Doped Multiwalled Carbon Nanotubes for Fenton-like Degradation of Paracetamol Under Mild Conditions

A series of carbon nanotubes doped with Fe and/or Cu, Fe100−xCux/CNT (x = 0, 25, 50, 75 and 100) has been prepared by an easy method of wetness impregnation of commercial multiwalled carbon nanotubes previously oxidized with nitric acid. The wide characterization of the solids by different techniques demonstrates that the incorporation of Fe and Cu to the CNTs has been successfully produced. Fe100−xCux/CNT samples were tested as catalysts in the removal of paracetamol from aqueous solution by a combined process of adsorption and Fenton-like oxidation. Under mild conditions, 25 °C and natural pH of solution, i.e., nearly neutral, values of oxidation of paracetamol between 90.2% and 98.3% were achieved after 5 h of reaction in most of cases. Furthermore, with the samples containing higher amounts of copper, i.e., Cu100/CNT and Fe25Cu75/CNT, only 2 h were necessary to produce depletion values of 73.2% and 87.8%, respectively. The influence of pH and dosage of H2O2 on the performance has also been studied. A synergic effect between both Cu+/Cu2+ and Fe2+/Fe3+ in Fenton-like reaction was observed. These results demonstrate that Fe100−xCux/CNT are powerful Fenton-like catalyst for degradation of paracetamol from aqueous solution and they could be extended to the removal of other organic pollutants.Ministerio de Ciencia e Innovación (CTM2014-56668-R)2017/UEM092018/UEM215.076 JCR (2020) Q1, 35/160 Physics, Applied0.919 SJR (2020) Q1, 49/394 Chemical Engineering (miscellaneous)No data IDR 2019UE

Rheological Properties of Different Graphene Nanomaterials in Biological Media

Carbon nanomaterials have received increased attention in the last few years due to their potential applications in several areas. In medicine, for example, these nanomaterials could be used as contrast agents, drug transporters, and tissue regenerators or in gene therapy. This makes it necessary to know the behavior of carbon nanomaterials in biological media to assure good fluidity and the absence of deleterious effects on human health. In this work, the rheological characterization of different graphene nanomaterials in fetal bovine serum and other fluids, such as bovine serum albumin and water, is studied using rotational and microfluidic chip rheometry. Graphene oxide, graphene nanoplatelets, and expanded graphene oxide at concentrations between 1 and 3 mg/mL and temperatures in the 25–40 °C range were used. The suspensions were also characterized by transmission and scanning electron microscopy and atomic force microscopy, and the results show a high tendency to aggregation and reveals that there is a protein–nanomaterial interaction. Although rotational rheometry is customarily used, it cannot provide reliable measurements in low viscosity samples, showing an apparent shear thickening, whereas capillary viscometers need transparent samples; therefore, microfluidic technology appears to be a suitable method to measure low viscosity, non-transparent Newtonian fluids, as it is able to determine small variations in viscosity. No significant changes in viscosity are found within the solid concentration range studied but it decreases between 1.1 and 0.6 mPa·s when the temperature raises from 25 to 40 °C