Compuestos

1. LA PALABRA HUMOR. El mundo esta dividido –y es tambien muy injustoen dos bandos: el bando de los graciosos, el de los que tienen chispa, el de los que han nacido para provocar la risa o la carcajada (quien no tiene ese amigo tan bueno para contar chistes) y el bando de los sosos, quizas mas amplio, el de los que no hemos sido tocados por la varita magica del salero y de la retranca. Cuando uno pertenece a este segundo grupo, tiene al menos el consuelo de disfrutar del humor. Y por eso voy a adentrarme en los diccionarios para ver como estan alli representados el humor, la socarroneria, la mala uva con que a veces utilizamos las palabras. Hay que aceptar, aunque nos cueste a los que nos dedicamos a su estudio, que los diccionarios, en general, son muy aburridos: las definiciones son siempre objetivas y serias 1

Different montmorillonites were added to poly(vinyl alcohol) in order to improve their properties. The used montmorillonite’s were: Cloisite Na+ (Na), Nanofil (NF), and Cloisite 30B (30B). Poly(vinyl alcohol) + montmorillonite films, obtained by casting, were characterized by means of Fourier transform infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis, X-ray diffraction pattern, transmission electron microscopy, water absorption, contact angle, and mechanical properties. Sodium and organically modified montmorillonites were used. The montmorillonite basal peak shifted to a lower angle for composites, with sodium montmorillonites, and the films were exfoliated–intercalated nanocomposites. Composites with organically modified montmorillonites presented a micro-morphology and the lowest water absorption. The best mechanical properties were obtained for the composite with sodium montmorillonites.

ABSTRACT The experimental program developed in this work aims at investigating the bond behavior of glass fiber reinforced plastic embedded in concrete. Different types of surface treatment were applied to the smooth rods in order to enhance the bond with concrete. Firstly, the rods were machined using a lathe and a grinding stone to create lugs with different configurations. The experimental results indicate that the bond strength is highest when the failure mode is a combination of two mechanisms: shearing off of the concrete lugs and that of the FRP lugs. With regard to the variation of rib width, the friction and interlock forces have a greater influence on bond strength. With respect to the height of the rib, the variation of internal diameter does not affect significantly the bond strength. Secondly, the machined rods were coated with sand fixed with a thin layer of epoxy resin. The incorporation of the sand on the surface increases the bond strength compared with the results obtained without sand.

The present study aims to experimentally validate numerical simulation of fiber orientation distribution performed by molding simulation software Moldex3D in a double-gated injection-molded glass fiber-filled (40 wt%) polypropylene box, by making a detailed comparison of predicted and experimentally measured fiber orientation distribution data. The modeling approach evaluated in this work consists in the implementation of the Folgar–Tucker rotary diffusion model with the invariant-based optimal fitting closure approximation for the fourth-order orientation tensor. The specimen used has a weld line in the center and sharp corners. This investigation characterizes in detail the development of the through-thickness layered structure at distinctive locations of the specimen. The sensitivity of fiber orientation distribution and the layered structure to changes upon injection time and melt temperature is also evaluated. The boxes display the typical layered laminate structure, with fiber...