277 research outputs found
Selective C(sp2)−H Halogenation of "click" 4-Aryl-1,2,3-triazoles
Selective bromination reactions of “click compounds” are described. Electron-neutral and electron-deficient arenes selectively undergo unprecedented Pd-catalyzed C–H ortho-halogenations assisted by simple triazoles as modular directing groups, whereas electron-rich arenes are regioselectively halogenated following an electrophilic aromatic substitution reaction pathway. These C–H halogenation procedures exhibit a wide group tolerance, complement existing bromination procedures, and represent versatile synthetic tools of utmost importance for the late-stage diversification of “click compounds”. The characterization of a triazole-containing palladacycle and density functional theory studies supported the mechanism proposal.We are grateful to Gobierno Vasco (ELKARTEK_KK-2015/0000101; IT_1033-16) and UPV/EHU (GIU15/31) for financial support. A. C. thanks MINECO for a Ramón y Cajal research contract (RYC-2012-09873). Cost-CHAOS action is also acknowledged
Comercialización de una aplicación móvil para dispositivos Android/iOS, enfocada en la recepción y gestión de canchas sintéticas en Bogotá y equipos de fútbol no profesionales.
El presente informe de trabajo de grado, tiene como principal objetivo presentar el plan de negocios para la creación de la aplicación móvil Dream Team, que permita gestionar los campeonatos y partidos de futbol en canchas sintéticas de Bogotá. Los elementos que se han tenido en cuenta para la elaboración del informe constan del análisis del mercado en el uso de canchas sintéticas y de aplicaciones móviles, el estudio técnico, la propuesta financiera y el análisis de la demanda creciente de canchas sintéticas en la ciudad.The main objective of this present work report is to present the business plan for the creation of the Dream Team mobile application, which will allow the management of championships and football matches on synthetic courts in Bogotá. The elements that have been taken into account for the preparation of the report consist of the analysis of the market in the use of synthetic courts and mobile applications, the technical study, the financial proposal and the analysis of the growing demand of synthetic courts in the city
Comercialización de una aplicación móvil para dispositivos Android/iOS, enfocada en la recepción y gestión de canchas sintéticas en Bogotá y equipos de fútbol no profesionales.
El presente informe de trabajo de grado, tiene como principal objetivo presentar el plan de negocios para la creación de la aplicación móvil Dream Team, que permita gestionar los campeonatos y partidos de futbol en canchas sintéticas de Bogotá. Los elementos que se han tenido en cuenta para la elaboración del informe constan del análisis del mercado en el uso de canchas sintéticas y de aplicaciones móviles, el estudio técnico, la propuesta financiera y el análisis de la demanda creciente de canchas sintéticas en la ciudad.The main objective of this present work report is to present the business plan for the creation of the Dream Team mobile application, which will allow the management of championships and football matches on synthetic courts in Bogotá. The elements that have been taken into account for the preparation of the report consist of the analysis of the market in the use of synthetic courts and mobile applications, the technical study, the financial proposal and the analysis of the growing demand of synthetic courts in the city
Composed multicore fiber structure for direction-sensitive curvature monitoring
The present work deals with a curvature sensor that consists of two segments of asymmetric multicore fiber (MCF) fusion spliced with standard single mode fiber (SMF). The MCF comprises three strongly coupled cores; one of such cores is at the geometrical center of the MCF. The two segments of MCF are short, have different lengths (less than 2 cm each), and are rotated 180 degrees with respect to each other. The fabrication of the sensor was carried out with a fusion splicing machine that has the means for rotating optical fibers. It is demonstrated that the sensor behaves as two SMF-MCF-SMF structures in series, and consequently, it has enhanced sensitivity. The device proposed here can be used to sense the direction and amplitude of curvature by monitoring either wavelength shifts or intensity changes. In the latter case, high curvature sensitivity was observed. The device can also be used for the development of other highly sensitive sensors to monitor, for example, vibrations, force, pressure, or any other parameter that induces periodic or local curvature or bending to the MCF segments.The authors acknowledge the financial support of the Spanish MINECO under Project Nos. PGC2018-101997-B-I00 and RTI2018-094669-B-C31 of the Eusko Jaurlaritza (Basque Government) under Project Nos. IT933-16 and ELKARTEK
Una propuesta lúdica pedagógica para aportar a la solución de los problemas de aprendizaje de las matemáticas en los estudiantes de 9,10 y 11 grado de la Institución Educativa José de La Vega, jornada de la tarde en el sector Santa Rita de la ciudad de Cartagena
El aprendizaje de las matemáticas, la lectura y la escritura, son aprendizajes preponderantes de la educación elemental, dado el carácter instrumental de estos contenidos, Por eso debemos entender que las dificultades en el aprendizaje de las matemáticas se hayan convertido en una preocupación manifiesta de buena parte de los docentes, especialmente si se considera el alto porcentaje de fracaso en el aprendizaje matemático que presentan nuestros estudiantes, por tanto echemos mano de la lúdica con apoyo de las tics, así como motivación a los padres de familia y nosotros mismos, los profesores, que somos piezas fundamentales en la culminación y alcance del éxito del proceso educativo
Preparation of organic monolithic columns in polytetrafluoroethylene tubes for reversed-phase liquid chromatography
[EN] In this work, a method for the preparation and anchoring of polymeric monoliths in a polytetrafluoroethylene (PTFE) tubing as a column housing for microbore HPLC is described. In order to assure a covalent attachment of the monolith to the inner wall of the PTFE tube, a two-step procedure was developed. Two surface etching reagents, a commercial sodium naphthalene solution (Fluoroetch®), or mixtures of H2O2 and H2SO4, were tried and compared. Then, the obtained hydroxyl groups on the PTFE surface were modified by methacryloylation. Attenuated total reflectance Fourier-transform infrared (ATR-FTIR) spectroscopy and scanning electron microscopy (SEM) confirmed the successful modification of the tubing wall and the stable anchorage of monolith to the wall, respectively. Special emphasis was also put on the reduction of the unwanted effects of shrinking of monolith during polymerization, by using an external proper mold and by selecting the adequate monomers in order to increase the flexibility of the polymer. Poly(glycidyl methacrylate-co-divinylbenzene) monoliths were in situ synthesized by thermal polymerization within the confines of surface-vinylized PTFE tubes. The modified PTFE tubing tightly held the monolith, and the monolithic column exhibited good pressure resistance up to 20 MPa. The column performance was also evaluated via the isocratic separation of a series of alkylbenzenes in the reversed-phase mode. The optimized monolithic columns gave plate heights ranged between 70 and 80 um. The resulting monoliths were also satisfactorily applied to the separation of proteins.This work was supported by projects CTQ2014-52765-R (MINECO of Spain and Fondo Europeo de Desarrollo Regional, FEDER) and PROMETEO/2016/145 (Conselleria d'Educacio, Investigacio, Cultura i Esport, Generalitat Valenciana, Spain). The authors also thank Dr. P. Amoros del Toro from Institute of Materials Science (University of Valencia) and Dr. S. Armenta from Department of Analytical Chemistry for their help in surface area and FT-IR measurements, respectively.Catalá-Icardo, M.; Torres-Cartas, S.; Meseguer-Lloret, S.; Gómez Benito, C.; Carrasco-Correa, E.; Simó-Alfonso, EF.; Ramis-Ramos, G.... (2017). Preparation of organic monolithic columns in polytetrafluoroethylene tubes for reversed-phase liquid chromatography. Analytica Chimica Acta. 960:160-167. https://doi.org/10.1016/j.aca.2017.01.01216016796
Sensitivity-optimized strongly coupled multicore fiber-based thermometer
[EN] In this paper, we report on a multicore fiber-based (MCF) temperature sensor that operates in a wide thermal range and that is robustly packaged to withstand harsh environments. To develop the sensor, the fundamentals concerning the effect of temperature on such fibers have been analyzed in detail to predict the most temperature sensitive MCF geometry. Thanks to it, the device, which operates in reflection mode and consists of a short segment of strongly coupled MCF fusion spliced to a standard single mode fiber, shows higher sensitivity than other devices with identical configuration. Regarding its packaging, it consists of an inner ceramic and two outer metallic tubes to provide rigidity and protection against impacts or dirt. The device was calibrated for a thermal range from -25 degrees C to 900 degrees C and a K-type thermocouple was used as reference. Our results suggest that the manufactured optical thermometer is as accurate as the electronic one, reaching a sensitivity up to 29.426 pm/degrees C with the advantage of being passive, compact and easy to fabricate and interrogate. Therefore, we believe this device is appealing for industrial applications that require highly sensitive temperature sensing in very demanding environments, and that the analysis included in this work could be analogously applied to develop sensitivity-optimized devices for other parameters of interest.Ministerio de Economia y Competitividad; Ministerio de Ciencia, Innovacion y Universidades; European Regional Development Fund (PGC2018-101997-B-I00 and RTI2018-094669-B-C31) ; Gobierno Vasco/Eusko Jaurlaritza (IT933-16) ; ELKARTEK KK-2019/00101 (mu 4Indust) and ELKARTEK KK-2019/00051 (SMARTRESNAK) . The work of Josu Amorebieta is funded by a PhD fellowship from the University of the Basque Country UPV/EHU. The work of Angel Ortega-Gomez is funded by a PhD fellowship from the MINECO (Ministerio de Economia y Empresa de Espana)
Highly Sensitive Multicore Fiber Accelerometer for Low Frequency Vibration Sensing
We report on a compact, highly sensitive all-fiber accelerometer suitable for low frequency and low amplitude vibration sensing. The sensing elements in the device are two short segments of strongly coupled asymmetric multicore fiber (MCF) fusion spliced at 180 degrees with respect to each other. Such segments of MCF are sandwiched between standard single mode fibers. The reflection spectrum of the device exhibits a narrow spectrum whose height and position in wavelength changes when it is subjected to vibrations. The interrogation of the accelerometer was carried out by a spectrometer and a photodetector to measure simultaneously wavelength shift and light power variations. The device was subjected to a wide range of vibration frequencies, from 1 mHz to 30 Hz, and accelerations from 0.76 mg to 29.64 mg, and performed linearly, with a sensitivity of 2.213 nW/mg. Therefore, we believe the accelerometer reported here may represent an alternative to existing electronic and optical accelerometers, especially for low frequency and amplitude vibrations, thanks to its compactness, simplicity, cost-effectiveness, implementation easiness and high sensitivity.Ministerio de Economia y Competitividad; Ministerio de Ciencia, Innovacion y Universidades; European Regional Development Fund (PGC2018-101997-B-I00 and RTI2018-094669-B-C31); Gobierno Vasco/Eusko Jaurlaritza (IT933-16); ELKARTEK KK-2019/00101 (mu 4Indust) and ELKARTEK KK-2019/00051 (SMARTRESNAK). The work of Angel Ortega-Gomez is funded by a PhD fellowship from the Spain Government. The work of Josu Amorebieta is funded by a PhD fellowship from the University of the Basque Country UPV/EHU
Statistical modeling of road contribution as emission sources to total suspended particles (TSP) under MCF model downtown Medellín – Antioquia - Colombia, 2004
RESUMEN: Entre las fuentes de emisión a la contaminación del aire en el Valle de Aburrá Zona Centro, se encuentran:
canchas de arena, fuentes biológicas, calderas de carbón, vías y construcciones, entre otras. La forma funcional de los aportes de las Vías a las partículas totales en suspensión generados por el modelo fuente-receptor, MCF, Modelo de Correlación de Fuentes, creado para la estimación en porcentaje del grado de contribución de una fuente de contaminación especifica, es aproximadamente la de una distribución Gamma. Aquí se utiliza la prueba de bondad de ajuste Chi-cuadrado para modelar estadísticamente los aportes de las Vías como fuentes de emisión a las partículas totales en suspensión durante un periodo determinado de tiempo. Esta prueba permite estimar también los parámetros de la distribución mediante el método de máxima verosimilitud. Como algoritmo de convergencia se ha utilizado el Algoritmo EM (Estimation Maximization Algorithm). La estimación de la media de los factores de contribución de las vías según el modelo Fuente-Receptor MCF es inmediata a partir de estas estimaciones y valida el factor de
contribución de las Vías a la contaminación atmosférica en la zona de estudio.ABSTARCT: Sand fields, constructions, carbon boilers, roads, and biologic sources are air-contaminant-constituent
factors in Down Town Valle de Aburrá, among others. The distribution of road contribution data to total suspended particles according to the source receptor model MCF, source correlation modeling, is nearly a Gamma distribution. Chi-square goodness of fit is used to model statistically. This test for goodness of fit also allows to estimate the parameters of the distribution utilizing maximum likelihood method. As a convergency criteria, the Estimation Maximization Algorithm is used. The mean of road contribution data to total suspended particles according to the source receptor model MCF, is straightforward and validates the road contribution factor to the atmospheric pollution of the zone under study
Compact Omnidirectional Multicore Fiber-Based Vector Bending Sensor
We propose and demonstrate a compact and simple vector bending sensor capable of distinguishing any direction and amplitude with high accuracy. The sensor consists of a short segment of asymmetric multicore fiber (MCF) fusion spliced to a standard single mode fiber. The reflection spectrum of such a structure shifts and shrinks in specific manners depending on the direction in which the MCF is bent. By monitoring simultaneously wavelength shift and light power variations, the amplitude and bend direction of the MCF can be unmistakably measured in any orientation, from 0 degrees to 360 degrees. The bending sensor proposed here is highly sensitive even for small bending angles (below 1 degrees).This work was funded in part by the Fondo Europeo de Desarrollo Regional (FEDER), in part by the Ministerio de Ciencia, Innovacion y Universidades-under projects RTC2019-007194-4, RTI2018-0944669-B-C31 and PGC2018-101997-B-and in part by the Gobierno Vasco/Eusko Jaurlaritza IT933-16, ELKARTEK KK-2019/00101 (mu 4Indust), and ELKARTEK KK-2019/00051 (SMARTRESNAK). The work of Josu Amorebieta is funded by a PhD fellowship from the University of the Basque Country UPV/EH
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