(2+1) null-plane quantum Poincar\'e group from a factorized universal RR-matrix

The non-standard (Jordanian) quantum deformations of $so(2,2)$ and (2+1) Poincar\'e algebras are constructed by starting from a quantum $sl(2,\R)$ basis such that simple factorized expressions for their corresponding universal $R$-matrices are obtained. As an application, the null-plane quantum (2+1) Poincar\'e Poisson-Lie group is quantized by following the FRT prescription. Matrix and differential representations of this null-plane deformation are presented, and the influence of the choice of the basis in the resultant $q$-Schr\"odinger equation governing the deformed null plane evolution is commented.Comment: 11 pages, LaTe

Application of the Verlet method for the simulation of a gravitational system of n bodies

En este trabajo se plantea una solución numérica (simulación por software) del “problema de n cuerpos” que interactúan gravitacionalmente basada en la formulación de Verlet. Adicionalmente se diseña un programa que gráficamente muestra los resultados de esta solución numérica, que detalla las diferentes trayectorias, para diferentes condiciones de masa, velocidad y distancia entre los n objetos que interactúan. La interacción del usuario con la interfaz gráfica, se realiza partícula a partículaIn this paper we propose a numerical solution (software simulation) of the "problem of n bodies" that interact gravitationally based on the formulation of Verlet. Additionally a program is designed that graphically shows the results of this numerical solution, which details the different trajectories, for different conditions of mass, speed and distance between the n objects that interact. The interaction of the user with the graphical interface, is performed particle by particle.Peer Reviewe

Print velocity effects on strain-rate sensitivity of acrylonitrile-butadiene-styrene using material extrusion additive manufacturing

The strain-rate sensitivity of the yield stress for Acrylonitrile-Butadiene-Styrene (ABS) tensile samples processed via material extrusion additive manufacturing (ME-AM) was investigated. Such specimens show molecular orientation and interstitial voids that affect the mechanical properties. Apparent densities were measured to compensate for the interstitial voids. Three different printing speeds were used to generate ME-AM tensile test samples with different molecular orientation. Printing velocities influenced molecular orientation and stretch, as determined from thermal shrinkage measurements. Likewise, infill velocity affected the strain-rate dependence of the yield stress. The ABS material manifests thermorheollogically simple behavior that can correctly be described by an Eyring flow rule. The changing activation volume, as a result of a varying print velocity, scales linearly with the molecular orientation, as captured in an estimated processing-induced pre-strain. Therefore, it is suggested that ME-AM processed ABS shows a deformation-dependent activation volume. This paper can be seen as initial work that can help to improve quantitative predictive numerical tools for ME-AM, taking into account the effects that the processing step has on the mechanical properties

Bacanora and Sotol: So Far, So Close

El propósito de este trabajo es familiarizar al lector con algunos aspectos relacionados, no sólo con dos bebidas alcohólicas de profundo arraigo en la cultura rural del México norteño, sino también con Agave angustifolia, conocido en Sonora como “agave (o mezcal) bacanora”; y un grupo de especies del género Dasylirion, conocido en México como “sotoles”, y “desert spoon” o ¨cuchara del desierto¨ en los Estados Unidos de América. Ambas comparten múltiples características morfológicas, fisiológicas y ecológicas que les permiten vivir en ambientes áridos. De igual forma, también intenta señalar aspectos únicos de las dos denominaciones de origen que protegen la elaboración de esas bebidas y que han surgido en los albores de este siglo, así como a las normas que rigen su elaboración

ESTUDIO COMPARATIVO DEL COMPORTAMIENTO FORRAJERO DE SIETE ECOTIPOS DE DIGITARIAS EN SUELOS DE ESPARTILLAR DEL CHACO CENTRAL.

Fueron evaluados siete ecotipos de Digitarias en la Estancia La Hermosa, ubicada en el distrito de Tte. 1º Irala Fernández, departamento de Pte. Hayes, Chaco Central. El periodo evaluado estuvo comprendido entre marzo de 2005 a enero del 2006. Se evaluaron la producción de materia seca en los periodos de otoño, invierno, primavera y verano. El diseño experimental adoptado fue el de bloques completamente al azar con siete tratamientos y tres repeticiones. Los tratamientos consistieron en cada ecotipo de Digitaria. Los cortes de evaluación se efectuaron cada 28 días y en forma sucesiva por un periodo de 11 meses. En el periodo otoñal se registraron rendimientos satisfactorios siendo el ecotipo más productivo Digitaria sp. cv. GL 5 con 8810 kg/ha de masa seca, y el menos productivoDigitaria eriantha var pentzii con 3405 kg/ha. En el periodo de invierno los rendimientos de masa seca disminuyeron en todos los ecotipos así Digitaria sp. cv. GL 5 produjo 2968 kg /ha que fue la mayor producción registrada y 1205 kg/ha la menor producción paraDigitaria eriantha cv. ATF 616. Durante el periodo primaveral se produjo un aumento en la producción de todos los ecotipos siendo Digitaria sp. cv. GL 5 con 5067 kg/ha de masa seca la más productiva en este periodo y Digitaria eriantha var pentzii el de menor rendimiento con 2053 kg/ha. Así mismo en el periodo estival todos los ecotipos expresaron su máxima producción, Digitaria sp. cv. GL 5 fue una vez más el ecotipo con mejor rendimiento con 11 120 kg/ha de masa seca y Digitaria eriantha var pentzii el ecotipo de con más bajo rendimiento

Chalcopyrite Leaching Kinetics in the Presence of Methanol

The dissolution of chalcopyrite under near ambient conditions represents one of the main challenges in the copper industry. Thus, various routes have been proposed for chalcopyrite treatment, such as the use of polar organic solvents, and this has shown promising results. In this paper, we present a study of copper leaching from a chalcopyrite concentrate in aqueous acidic medium with methanol and various H2O2 concentrations at 15, 30, and 40 °C. The results show that nearly complete copper extraction was attained within 5 h at 40 °C. The extraction percentages were plotted as functions of time at each temperature. The experimental data were modeled using the shrinking core model considering the cylindrical particle shape (shrinking cylinder model) within acceptable confidence levels, yielding an estimated activation energy of 24.3 kJ/mol. Furthermore, the process was dependent on the H2O2 concentration, and it acts as a reagent rather than an oxidant in the leaching reaction. It was found that sulfur is the only species present in the solid phase formed during the leaching of chalcopyrite, demonstrating the co-dissolution of both copper and iron

A turn-on fluorescent solid-sensor for Hg(II) detection

A rhodamine organosilane derivative (Rh-UTES) has been obtained by one-pot synthesis. The chemical structure of Rh-UTES was confirmed by nuclear magnetic resonance (NMR) and infrared (FTIR) techniques. To obtain an inorganic-organic hybrid sensor, Rh-UTES was covalently immobilized on a porous silicon microcavity (PSiMc) via triethoxysilane groups. The attachment of the organic derivative into PSiMc was confirmed by FTIR, specular reflectance, and scanning electron microscopy (SEM). The optical performance of Rh-UTES receptor for Hg2+ detection was investigated by fluorescent spectroscopy and microscopy. Upon the addition of increasing amounts of Hg2+ ions, a remarkable enhancement in emission intensity was produced in both systems. In the solid phase, an increase of integrated fluorescent emission of 0.12- and 0.15-fold after Hg2+ receptor coordination was observed. The light harvesting capability of PSiMc devices allowed obtaining an enhanced fluorescent emission after Rh-UTES immobilization (277-fold). The fluorescence microscopy of hybrid PSiMc sensor provided an optical qualitative test for Hg2+ detection.A rhodamine organosilane derivative (Rh-UTES) has been obtained by one-pot synthesis. The chemical structure of Rh-UTES was confirmed by nuclear magnetic resonance (NMR) and infrared (FTIR) techniques. To obtain an inorganic-organic hybrid sensor, Rh-UTES was covalently immobilized on a porous silicon microcavity (PSiMc) via triethoxysilane groups. The attachment of the organic derivative into PSiMc was confirmed by FTIR, specular reflectance, and scanning electron microscopy (SEM). The optical performance of Rh-UTES receptor for Hg2+ detection was investigated by fluorescent spectroscopy and microscopy. Upon the addition of increasing amounts of Hg2+ ions, a remarkable enhancement in emission intensity was produced in both systems. In the solid phase, an increase of integrated fluorescent emission of 0.12- and 0.15-fold after Hg2+ receptor coordination was observed. The light harvesting capability of PSiMc devices allowed obtaining an enhanced fluorescent emission after Rh-UTES immobilization (277-fold). The fluorescence microscopy of hybrid PSiMc sensor provided an optical qualitative test for Hg2+ detection

Formylation as a Chemical Tool to Modulate the Performance of Photosensitizers Based on Boron Dipyrromethene Dimers

Heavy-atom-free photosensitizers are envisioned as the next generation of photoactive molecules for photo-theragnosis. In this approach, and after suitable irradiation, a single molecular scaffold is able to visualize and kill tumour cells by fluorescence signalling and photodynamic therapy (PDT), respectively, with minimal side effects. In this regard, BODIPY-based orthogonal dimers have irrupted as suitable candidates for this aim. Herein, we analyse the photophysical properties of a set of formyl-functionalized BODIPY dimers to ascertain their suitability as fluorescent photosensitizers. The conducted computationally aided spectroscopic study determined that the fluorescence/singlet oxygen generation dual performance of these valuable BODIPY dimers not only depends on the BODIPY-BODIPY linkage and the steric hindrance around it, but also can be modulated by proper formyl functionalization at specific chromophoric positions. Thus, we propose regioselective formylation as an effective tool to modulate such a delicate photonic balance in BODIPY-based dimeric photosensitizers. The taming of the excited-state dynamics, in particular intramolecular charge transfer as the key underlying process mediating fluorescence deactivation vs. intersystem crossing increasing, could serve to increase fluorescence for brighter bioimaging, enhance the generation of singlet oxygen for killing activity, or balance both for photo-theragnosis.This research received financial support from the Spanish Ministerio de Ciencia e Innovación (MCIN)/Agencia Estatal de Investigación (AEI) Grants: PID2020-114755GB-C32 and -C33 funded by MCIN/AEI/10.13039/501100011033. Gobierno Vasco (IT1639-22) is also grateful for the financial support

An asymmetric BODIPY triad with panchromatic absorption for high-performance red-edge laser emission

© The Royal Society of Chemistry 2015. A rational design of an unprecedented asymmetric cassette triad based entirely on BODIPY chromophores allows efficient light harvesting over the UV-vis spectral region, leading to a bright and stable red-edge laser emission via efficient energy-transfer processes.Peer Reviewe