Effect of Rare Earth Ions on the Properties of Composites Composed of Ethylene Vinyl Acetate Copolymer and Layered Double Hydroxides

BACKGROUND: The study on the rare earth (RE)-doped layered double hydroxides (LDHs) has received considerable attention due to their potential applications in catalysts. However, the use of RE-doped LDHs as polymer halogen-free flame retardants was seldom investigated. Furthermore, the effect of rare earth elements on the hydrophobicity of LDHs materials and the compatibility of LDHs/polymer composite has seldom been reported. METHODOLOGY/PRINCIPAL FINDINGS: The stearate sodium surface modified Ni-containing LDHs and RE-doped Ni-containing LDHs were rapidly synthesized by a coprecipitation method coupled with the microwave hydrothermal treatment. The influences of trace amounts of rare earth ions La, Ce and Nd on the amount of water molecules, the crystallinity, the morphology, the hydrophobicity of modified Ni-containing LDHs and the adsorption of modifier in the surface of LDHs were investigated by TGA, XRD, TEM, contact angle and IR, respectively. Moreover, the effects of the rare earth ions on the interfacial compatibility, the flame retardancy and the mechanical properties of ethylene vinyl acetate copolymer (EVA)/LDHs composites were also explored in detail. CONCLUSIONS/SIGNIFICANCE: S-Ni₀.₁MgAl-La displayed more uniform dispersion and better interfacial compatibility in EVA matrix compared with other LDHs. Furthermore, the S-Ni₀.₁MgAl-La/EVA composite showed the best fire retardancy and mechanical properties in all composites

Apoyo en la elaboración de documentos de divulgación científica en una red social temática

Este documento describe a MInv, una red social temática cuyo objetivo es apoyar la elaboración de documentos académicos requeridos en una comunidad universitaria. MInv incorpora ontologías para representar el conocimiento del dominio, formado por conceptos de metodología de la investigación. Además de las herramientas de comunicación y de las tareas de los usuarios en una red social, el uso de tecnologías semánticas permite separar el conocimiento del dominio del operativo, así como la posibilidad de elaborar consultas en las que se requiera algún tipo de inferencia lógica. El documento muestra secciones de la interfaz y describe elementos de las ontologías.This paper describes MInv, a thematic social network with the goal of supporting the elaboration of documents in an academic community. MInv uses ontologies to represent the domain knowledge formed mainly by research methodology concepts. Besides the communication tools of the web 2.0 and the typical functions of social networks, the use of semantic technologies in MInv enables the separation of domain knowledge from operative knowledge; these technologies allow users to make queries that often require a type of of logic inference. The paper shows some section of Minv interface and describe the classes and properties of the proposed ontologies

Modelo de Gestión de Datos Compartidos de Producción Científica

En instituciones de educación superior (IES), es común que la evaluación de la investigación se realice con base en indicadores que de forma cuantitativa, estiman la calidad de productos científicos. Este documento describe un modelo de gestión de datos compartidos de publicaciones y proyectos, con diseño adaptable a otros productos, que permite la recolección de datos y su descripción con estándares de metadatos, con el propósito de agregar valor práctico a los datos de las IES y posibilitar la colaboración entre profesores al hacer público la producción de los usuarios. El modelo se ha implementado como una aplicación web diseñada desde la perspectiva de los sistemas de organización y sus diferentes niveles de conocimiento. Los usuarios de la aplicación web realizan tareas como inserciones, bajas, consultas, reportes y exportación de datos al formato Bibtex. Las consultas se llevan a cabo a nivel personal, general o bien, se puede acceder a la producción de cualquier otro usuario

Functionalised pseudo-boehmite nanoparticles as an excellent adsorbent material for anionic dyes

Pseudo-boehmite has been functionalised with L-lysine by refluxing an aqueous solution containing these two reactants overnight. The resulting nanosized (<10 nm) product is insoluble in water and has been characterised by solid-state NMR spectroscopy, powder X-ray diffraction analysis, N2 adsorption–desorption analysis and zeta potential measurements. The affinity of this new nanostructured organic–inorganic hybrid material for anionic dyes has been quantified using UV-vis spectrophotometry and by constructing the adsorption isotherms for Acid Blue 9 (AB9), Acid Yellow 23 (AY23), and Acid Red 37 (AR37). Elemental/micro analyses indicate that one lysine molecule is covalently bonded to every 8 nm2 of the functionalised material giving a composition [(AlOOH)230·(H2O)86·(C6N2O2H15)]. The introduction of the positively charged amino groups resulted in a tremendous increase in dye affinity in contrast to the unfunctionalised material. The adsorption isotherms of the functionalised pseudo-boehmite were fitted to the Langmuir model and yielded equilibrium binding constants (Ka) of 2.6 × 103 M−1 for AB9, 1.5 × 105 M−1 for AY23 and 8.4 × 104 M−1 for AR37. AR37 gave a higher monolayer coverage (Cm) value of 0.13 mmol g−1 than AB9 (0.085 mmol g−1) and AY23 (0.081 mmol g−1). Dye adsorption is correlated with surface coverage of L-lysine and, in the case of AR37, two dye molecules are concluded to be adsorbed per L-lysine while for AY23 a multi-point interaction is proposed to result in a lower dye capacity and a relatively higher affinity of this dye for FPB when compared with AR37