Evaluación preliminar de emisiones de plomo en automóviles

El presente trabajo reporta emisiones de plomo contenido en el material particulado emitido por el escape. de una muestra típica de automóviles a gasolina, mediame muestreo isocinético a volumen constante según normas de la Environmental Protection Agency de USA. Los resultados obtenidos muestran ww emisión promedio de 7.4 ± 0.68 (mg Pb · km- 1) obtenido al aplicar un ciclo de conducción representativo de la A 1·enida Bemardo O'Higgins en el área de restricción vehicular. simulado en dinamómetro de rodillos y a través de dilución variable de gases de escape. Este valor sugiere que la información utilizada en la evaluación de los inventarios de emisiones en Santiago, sobredimensiona la contribución del material particulado proveniente de vehículos livianos a gasolina

New features in the ionic states of N2O4: Experimental and theoretical study

We present a combined experimental and theoretical study focused on the ionic states of the N2O4 molecule. Experimental results regarding photoionization induced by the synchrotron radiation SOLEIL in the 13.5-15.5 eV energy range were obtained using the electron-ion velocity vector correlation method. The potential energy curves for the dissociation of the N-N bond were computed within ab initio multireference wave functions based methods (CASSCF and CASPT2) for the first electronic states of N2O 4 and N2O4

Comparación de efectos de un aditivo comercial y un encendido por descarga continua sobre las emisiones primarias de un motor de automóvil

El presente trabajo muestra un estudio comparativo de las emisiones de S02 , NOx, HCHO, CO y HC producidas por un motor Datsun 1 .5 L acoplado a un dinanómetro hidráulico. En un caso, se usó un sistema de encendido por "descarga continua" y en el otro, se usó un aditivo comercial "For Gas" marca Wynn' s. En las condiciones analizadas, el aditivo comercial mostró una mayor eficiencia en la reducción de contaminames, que el encendido electrónico. En particular, las emisiones de S02 se redujeron hasta un 20% comparativas al sistema convencional

Catalytic asymmetric synthesis of diazabicyclo[3.1.0]hexanes by 1,3-dipolar cycloaddition of azomethine ylides with azirines

Substituted 1,3-diazabicyclo[3.1.0]hexanes with two contiguous quaternary stereocentres are readily prepared by catalytic asymmetric [3+2] cycloaddition of α-substituted iminoesters with azirines. High diastereoselectivities and enantioselectivities (up to 98% ee) are achieved using CuI/(R)-Fesulphos as the catalytic systemWe thank the Spanish Ministerio de Economía, Industria y Competitividad (Grant CTQ2015-66954-P, MINECO/FEDER, UE) and FEDER/Ministerio de Ciencia, Innovación y Universidades – Agencia Estatal de Investigación (Grant PGC2018-098660-B-I00) for financial suppor

Fractal Topological Analysis for 2D Binary Digital Images

Fractal dimension is a powerful tool employed as a measurement of geometric aspects. In this work we propose a method of topological fractal analysis for 2D binary digital images by using a graph-based topological model of them, called Homological Spanning Forest (HSF, for short). Defined at interpixel level, this set of two trees allows to topologically describe the (black and white) connected component distribution within the image with regards to the relationship “to be surrounded by”. This distribution is condensed into a rooted tree, such that its nodes are connected components determined by some special sub-trees of the previous HSF and the levels of the tree specify the degree of nesting of each connected component. We ask for topological auto-similarity by comparing this topological description of the whole image with a regular rooted tree pattern. Such an analysis can be used to directly quantify some characteristics of biomedical images (e.g. cells samples or clinical images) that are not so noticeable when using geometrical approaches.Ministerio de Economía y Competitividad TEC2016-77785-PMinisterio de Economía y Competitividad MTM2016-81030-

A comprehensive examination of the local- and long-range structure of Sb6O13 pyrochlore oxide

The crystal structure of the Sb6O13 oxide, exhibiting a defect pyrochlore crystal structure with atomic vacancies, has been studied using a complete set of state-of-the-art techniques. The degree of antimony disproportionation in Sb3+ and Sb5+ valence states has been directly determined around 36% and 64%, respectively, using X-ray absorption near edge structure (XANES). These findings are in excellent agreement with our Rietveld analysis of synchrotron X-ray (SXRD) and neutron powder diffraction (NPD) results. Moreover, the highly distorted Sb3+ coordination due to its lone electron pair has been critically revisited. The bonding distances and coordination of Sb3+ and Sb5+ species closely agree with an extensive dynamic and crystallographic determination using the Extended X-ray Absorption Fine Structure (EXAFS) technique. Most importantly, the specific local disorder of the two distinctive Sb ions has been crosschecked monitoring their unusual Debye–Waller factors.Fil: Mayer, Sergio Federico. Instituto de Ciencia de Materiales de Madrid; España. Universidad Tecnológica Nacional. Facultad Regional Córdoba. Centro de Investigación en Nanociencia y Nanotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Rodrigues, Joao Elias. Universidade de Sao Paulo; Brasil. Instituto de Ciencia de Materiales de Madrid; EspañaFil: Marini, C.. CELLS–ALBA Synchrotron; EspañaFil: Fernández-Díaz, M.T.. Institut Laue Langevin; FranciaFil: Falcón, H.. Universidad Tecnológica Nacional. Facultad Regional Córdoba; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigación y Tecnología Química. Universidad Tecnológica Nacional. Facultad Regional Córdoba. Centro de Investigación y Tecnología Química; ArgentinaFil: Asensio, M. C.. Consejo Superior de Investigaciones Científicas; España. Instituto de Ciencia de Materiales de Madrid; EspañaFil: Alonso, J. A.. Instituto de Ciencia de Materiales de Madrid; Españ

A comprehensive examination of the local- and long-range structure of Sb6O13 pyrochlore oxide

The crystal structure of the Sb6O13 oxide, exhibiting a defect pyrochlore crystal structure with atomic vacancies, has been studied using a complete set of state-of-the-art techniques. The degree of antimony disproportionation in Sb3+ and Sb5+ valence states has been directly determined around 36% and 64%, respectively, using X-ray absorption near edge structure (XANES). These findings are in excellent agreement with our Rietveld analysis of synchrotron X-ray (SXRD) and neutron powder diffraction (NPD) results. Moreover, the highly distorted Sb3+ coordination due to its lone electron pair has been critically revisited. The bonding distances and coordination of Sb3+ and Sb5+ species closely agree with an extensive dynamic and crystallographic determination using the Extended X-ray Absorption Fine Structure (EXAFS) technique. Most importantly, the specific local disorder of the two distinctive Sb ions has been crosschecked monitoring their unusual Debye–Waller factors.Fil: Mayer, Sergio Federico. Instituto de Ciencia de Materiales de Madrid; España. Universidad Tecnológica Nacional. Facultad Regional Córdoba. Centro de Investigación en Nanociencia y Nanotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Rodrigues, Joao Elias. Universidade de Sao Paulo; Brasil. Instituto de Ciencia de Materiales de Madrid; EspañaFil: Marini, C.. CELLS–ALBA Synchrotron; EspañaFil: Fernández-Díaz, M.T.. Institut Laue Langevin; FranciaFil: Falcón, H.. Universidad Tecnológica Nacional. Facultad Regional Córdoba; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigación y Tecnología Química. Universidad Tecnológica Nacional. Facultad Regional Córdoba. Centro de Investigación y Tecnología Química; ArgentinaFil: Asensio, M. C.. Consejo Superior de Investigaciones Científicas; España. Instituto de Ciencia de Materiales de Madrid; EspañaFil: Alonso, J. A.. Instituto de Ciencia de Materiales de Madrid; Españ

Triplet formation inhibits amplified spontaneous emission in perylene-based polycyclic aromatic hydrocarbons

Polycyclic Aromatic Hydrocarbons (PAHs) have demonstrated potential as active laser materials, showing good Amplified Stimulated Emission (ASE) properties. However, the molecular origin of their ASE properties is still unclear and depends on the particular compound. In this work we study the ASE properties of polystyrene films hosting three different perylene-based PAHs YZ-1, YZ-2 and YZ-3, where only YZ-3 has displayed ASE. Their molecular structure has been systematically changed to establish the connection between their molecular structure and their ASE properties. A complete spectroscopic study, with ground state and time-resolved techniques, show that, even at low yields, triplets play a critical role as a major loss mechanism. Their slow relaxation to ground state completely hinders the required unbalance of the S1 and S0 states for succesful ASE. Quantum chemical calculations suggest that a lower triplet density of states for YZ-3 is responsible for the blockage in triplet formation and, therefore, does not restrict ASE. This work not only presents a new PAH showing ASE, but also unequivocable proves the massive importance of triplet states in the development of organic lasers.JW acknowledges financial support from A*STAR AME grant (A20E5c0089). The group at the University of Alicante thanks financial support from the “Ministerio de Ciencia e Innovación” (MCIN) of Spain and the European Regional Development Fund (grant No. PID2020-119124RB-I00) and from the Generalitat Valenciana though grant No. AICO/2021/093. Besides, this study is part of the Advanced Materials program supported by the Spanish MCIN with funding from European Union Next Generation EU and by Generalitat Valenciana (grant no. MFA/2022/045). The group at the UA thanks Dr. J.M Villalvilla and Dr. J.A. Quintana for useful discussions. We also thank the Research Central Services (SCAI) of the University of Málaga for the access to the EVI, EEL and MENL to perform ground state and transient spectroscopic characterisation. JC thanks funding provided by MINECO/FEDER (PID2021-127127NB-I00, PID2019-110305GB-I00) and Junta de Andalucía (PROYEXCEL-0328)

Detailed damage mechanisms assessment in composite materials by means of X-ray tomography

This research focused on the evaluation of damage formation on ±45º carbon fiber laminates subjected to tensile tests. The damage was evaluated by means of X-ray tomography. A high density of cracks developed during the plateau of the stress-strain curve and were qualitatively analyzed, showing that the inner plies eventually developed a higher crack concentration than the outer plies. Delamination started to occur in the outermost ply interface when the slope after the plateau of the stress-strain curve began to increase

Constructed wetland design for produced water treatment on a colombian petroleum field

En el presente artículo se plantea una alternativa de solución al gran problema que enfrentan los campos de petróleo de Colombia, con respecto al manejo y disposición del agua de producción. En su mayoría, estos  campos de petróleo asumen grandes costos para el tratamiento, manejo y disposición de la misma. El artículo describe el diseño de un humedal construido a escala real, propuesto como tratamiento secundario para una posible implementación de tratamiento del agua de producción. Para el diseño se tuvieron en cuenta las características fisicoquímicas del agua afluente del campo petrolero colombiano como concentraciones de materia orgánica (DBO5) y sólidos suspendidos totales (SST), acorde con los principales criterios de diseño de la tecnología, como tipo y concentración de contaminantes, tipología de humedal, caudal de entrada y área total requerida. una vez seleccionado el tipo de humedal, el diseño contempló las variables que afectan principalmente su desempeño, incluyendo procedimientos de operación y manejo para su implementación. El diseño consistió en un Humedal Construido de  flujo Sub-Superficial Horizontal (HC fSSH) de 120.000 m2 de superficie y una profundidad de 2 ft para tratar un caudal de 678.607 Bbl/d. El HC de fSSH consistió en 60 celdas de 109,35 ft por 196,85 ft dispuestas en paralelo (12) y en serie (5), plantadas con macrófitas acuáticas nativas para potencializar los procesos de depuración. Este diseño con una gran cantidad de área superficia, se considera compensado por los bajos costos de operación y mantenimiento, calculados para un período de 10 años; Mientras que un sistema convencional de tratamiento de agua de producción en un campo petrolero, invierte 4.380.338,1 uS$por año, un HC de fSSH opera con 23.681,78 uS$ para el mismo período de tiempo. La implementación de esta tecnología para el tratamiento de aguas residuales de la industria petrolera, se considera una alternativa viable, siempre y cuando se tengan los terrenos disponibles para su funcionamiento.  The development of this paper permits to find and set a new and alternative solution to the big problem that Colombian petroleum fields are facing: Management and Disposal of produced water. Due to the conventional treatment facilities, petroleum companies are spending great amounts of money to treat and dispose petroleum wastewaters. The present project describes a full-scale constructed wetland design proposed as a secondary treatment for a Colombian field produced water. The design takes into account the physicochemical characteristics of a Colombian field water affluent, represented as organic matter (BOD) and Total Suspended Solids (TSS) oncentrations, according to the main design criteria for the technology, like type and ollutants concentrations, type of wetland, entrance water rate and total area required. Once the type of wetland is selected, the design realizes the principal constraints that affect wetland performance, including operational and maintenance procedures for a future implementation. The design consists in a Horizontal Subsurface flow Constructed Wetland (HSSf CW) with 12 ha of superficial area and 2 ft depth, to treat an average water rate of 678.607 Bbl/day. The HSSf CW consisted on 60 cells of 109,35 x 196,85 ft each, organized in parallel (12) and in series (5). Each cell will be planted with native aquatic macrophytes to enhance purification processes. This grand superficial area design is considered compensated by the low operational and maintenance costs, calculated for a 10-year period. While a conventional treatment system for produced water needs an inversion of US$4.380.338,1 per year, a HSSF CW works with US$23.681,78 for the same time period