Síntesis y caracterización de óxidos mixtos precursores de bronces tetragonales de W de potencial actividad en la oxidación de difenilsulfuro

Fases de heteropolioxometalatos (HPOM), a base de heteropolitungstatos complejos derivados de tipo Keggin de la serie [M4(H2O)2(PW9O34)2]10- (PWM) con M(II) = Cu y su precursor Na8H(PW9O34) (PW9), se han modificado químicamente mediante reacción hidrotermal, con iones Nb y V en el gel de síntesis, dando lugar a la formación de materiales del tipo (KNaCu)xP0.11WV0,2NbOx y (Na)xPWV0,2NbOx. Tanto los materiales de síntesis como los tratados a 500ºC (en atmosfera de N2) son pseudocristalinos (que tras tratamiento a 800º C, conduce a una estructura típica de bronce tetragonal). Los materiales tratados térmicamente a 500ºC se han caracterizado y estudiado como catalizadores en la oxidación parcial de difenilsulfuro. Los resultados catalíticos se han comparado con los obtenidos con los HPOM de partida, observándose que los bronces metálicos presentan una mayor actividad catalítica (con una drástica disminución del tiempo de reacción) y un marcado aumento de la selectividad a difenil-sulfona.Phases based on complex heteropolytungstates (HPOM), derived from series Keggin type [M4 (H2O)2 (PW9O34)2] 10-(PWM) with M(II) = Cu and its precursor Na8H (PW9O34) (PW9), have been chemically modified by hydrothermal reaction, with Nb and V ions in the synthesis gel, giving place materials as (KNaCu)xP0.11WV0,2NbOx and (Na)xPWV0,2NbOx. The as-synthesized and the heat-treated at 500ºC (in N2) are pseudocrystalline (although they are transformed to tetragonal bronze after heattreatment at 800ºC). The samples heat-treated at 500ºC have been characterized and tested in the partial oxidation of diphenylsulfide. The catalytic results have been compared to those achieved over pure HPOM. It has been observed that these metal oxides bronzes show a higher both catalytic activity (with a drastic reduction of the reaction time) and selectivity to diphenyl-sulfone

Threading Through Macrocycles Enhances the Performance of Carbon Nanotubes as Polymer Fillers

In this work we study the reinforcement of polymers by mechanically interlocked derivatives of single-walled carbon nanotubes (SWNTs). We compare the mechanical properties of fibers made of polymers and of composites with pristine single-walled carbon nanotubes (SWNTs), mechanically interlocked derivatives of SWNTs (MINTs) and the corresponding supramolecular models. Improvements of both Young's modulus and tensile strength of up to 200 % were observed for the polystyrene-MINTs samples with an optimized loading of just 0.01 wt.%, while the supramolecular models with identical chemical composition and loading showed negligible or even detrimental influence. This behavior is found for three different types of SWNTs and two types of macrocycles. Molecular dynamics simulations show that the polymer adopts an elongated conformation parallel to the SWNT when interacting with MINT fillers, irrespective of the macrocycle chemical nature, whereas a more globular structure is taken upon facing with either pristine SWNTs or supramolecular models. The MINT composite architecture thus leads to a more efficient exploitation of the axial properties of the SWNTs and of the polymer chain at the interface, in agreement with experimental results. Our findings demonstrate that the mechanical bond imparts distinctive advantageous properties to SWNT derivatives as polymer fillers.Comment: 39 pages, 19 figure

Thorpe method applied to planetary boundary layer data

Turbulence affects the dynamics of atmospheric processes by enhancing the transport of mass, heat, humidity and pollutants. The global objective of our work is to analyze some direct turbulent descriptors which reflect the mixing processes in the atmospheric boundary layer (ABL). In this paper we present results related to the Thorpe displacements dT , the maximum Thorpe displacement (dT )max and the Thorpe scale LT , the Ozmidov scale and their time evolution in the ABL during a day cycle. A tethered balloon was used to obtain vertical profiles of the atmospheric physical magnitudes up to 1000m. We discuss the vertical and horizontal variability and how different descriptors are related to atmospheric mixing

Continuous Plasma density measurement in TJ-II infrared interferometer-Advanced signal processing based on FPGAs

This work presents the behavioral simulation in an FPGA of a novel processing system for measuring line average electronic density in the TJ-II stellarator diagnostic, Infra-Red Two-Color Interferometer. Line average electronic density is proportional to phase difference between probing and reference signals of the interferometer, as the Appleton–Hartree cold plasma model states. The novelty of the approach is the development of a real time measuring system where research work has been carried out in two ways: a new interpolation algorithm and the implementation of a new specific processor on an FPGA. The main goal of this new system is to measure line plasma electronic density for several channels in real time, also it will be useful to eliminate intermediate mixing frequency stages (the output signals coming from the interferometer are going to be directly sampled) and finally to generate real time density signals for control purposes in TJ-II and in other diagnostics. This device is intended to be the new data acquisition-processing system for the future six channel infrared interferometer that requires at least 14 input signals. The knowledge acquired could be useful in the design of W7-X and ITER IR-interferometer data acquisition and processing systems

Isolation and identification by high resolution liquid chromatography tandem mass spectrometry of novel peptides with multifunctional lipid-lowering capacity

This work describes the isolation, characterization, and identification by RP-HPLC-ESI-Q-TOF of novel peptides that interfere in the fat digestion and absorption mechanisms by multiple pathways. Peptides were ultrafiltrated and peptides in the most active fraction were further separated by semipreparative RP-HPLC. Nine different subfractions were obtained observing a high amount of peptides in subfraction F3. Peptides in subfraction F3 could simultaneously reduce the solubility of cholesterol in micelles and inhibit pancreatic cholesterol esterase and pancreatic lipase, even after a simulated gastrointestinal digestion. The identification of lipid-lowering peptides has been scarcely performed and when done, low selectivity or sensitivity of employed identification techniques or conditions did not yield reliable results. Separation and detection of peptides by RP-HPLC-ESI-Q-TOF-MS was optimized and most favorable conditions were employed for the identification of peptides using de novo sequencing. Ten different peptides with 4-9 amino acids were identified. Main feature of identified peptides was the high acidity derived from a high presence of amino acids glutamic acid and aspartic acid in their sequences

Para asombrarse y aprender

Este trabajo presenta la fundamentación, diseño y resultados de un proyecto realizado en el marco de un programa institucional en la UNAM, relacionado con la innovación de la enseñanza experimental. Como producto de este proyecto se elaboró un libro con 30 experimentos de aula dirigidos a profesores de los niveles bachillerato y universitario. Los experimentos elaborados presentan propuestas experimentales novedosas que nos permitan reconceptualizar y diversificar el trabajo práctico

Una nueva especie de Aphis Linnaeus, 1758 (Hemiptera, Aphididae) recogida sobre Gymnophyton Clos (Apiaceae) en Argentina

Aphis cuyana López Ciruelos & Ortego, sp. n. (Aphididae, Aphidinae) is described from apterous and alate viviparous females collected on Gymnophyton polycephalum (Apiaceae) in localities of the Argentinean provinces of La Rioja, San Juan and Mendoza. A table with differences of the apterous viviparous females of the new species from the species of Aphis and its close genera Andinaphis and Protaphis known in South America is presented. http://urn:lsid:zoobank.org:pub:4834FEF4-171C-4EBD-BF91-2137B517491ESe describe Aphis cuyana López Ciruelos & Ortego, sp. n. (Aphididae, Aphidinae) a partir de hembras vivíparas ápteras y aladas recogidas sobre Gymnophyton polycephalum (Apiaceae) en localidades de las provincias argentinas de La Rioja, San Juan y Mendoza. Se presenta una tabla con las diferencias de las hembras vivíparas ápteras de la nueva especie con las de Aphis y sus géneros vecinos Andinaphis y Protaphis, conocidas en América del Sur

A Course of Thermodynamics for an Industrial Engineering Degree using New Methodologies and Technologies

This paper presents the experience carried out at the Industrial Engineering School (ETSII) of the Universidad Politécnica de Madrid (UPM) for teaching Thermodynamics science using new methodologies and technologies. During the last two years a special course on Thermodynamics has been given to those students who failed to pass the ordinary examination. This group was made of around thirty students with some level of knowledge of the subject. Nontraditional teaching methodologies have been applied to this group stretching the potential of new technologies to the maximum possible extent. A complete e-learning system developed by our University called Aula Web was used to produce a weekly schedule for each individual student. Aula Web consists of several modules. News and Forum channel the communications with the student.“Contents” is a repository holding various types of learning material such us presentations, theoretical texts and problems with solutions. “Activities” assigns homework to the student who can submit it electronically. Finally, “Self-assessment” composes bespoke self-assessment tests resorting to a wide database of questions and short problems. A totally personalized long problem was programmed using MATLAB. The problem is structured in ten steps that help the student to progress towards his/her learning target. Upon conclusion of the learning program the student should have acquired all foreseen knowledge of the subject. Observed results are very satisfactory. Throughout the whole process the level of motivation of the students has been very high. The Universidad Politécnica de Madrid supports education innovation experiences through special programs whose main target is the convergence at the European Higher Education Space

The role of impulsivity in dropout from treatment for cigarette smoking

AbstractImpulsivity is a variable that has been associated with drug use. This study analyzes impulsivity from two different paradigms, one considering it as a trait and the other based on its behavioral correlates, such as disinhibition and impulsive decision-making in the treatment prognosis (maintain abstinence, relapse and dropout) of smokers after outpatient treatment. The participants in the study were 113 smokers who requested treatment for nicotine addiction. They were assigned to three groups according to whether or not they remained abstinent one month after beginning treatment; thus, group 1 was abstinent, group 2 had relapsed, and group 3 had dropped out of treatment. The participants filled out the Semi-structured Interview for Smokers, the Fargerström Test for Nicotine Dependence, the Temperament and Character Inventory-Revised (TCI-R) and the Delay Discounting Task (DDT). The Delay Discounting variable presents lower scores in the dropout group than in the relapse and abstinent groups, with the highest scores in the relapse group. Differences were also found on the Harm Avoidance (HA) variable, with lower scores in the dropout group compared to the relapse group. The importance of these results lies in the consideration of the smoker’s personality profile in order to prevent both dropout and relapse