Effect of PH on lhe control release o microencapsulated dye in lecithin liposomes

The objective of our work has been the microencapsulation of dyes with lecithin from soybean, with the formation of liposomes, as a substitute for synthetic auxiliaries so as to improve the quality of the effluent. Current scenarios promote the disintegration and leakage of the liposomes, such as, changes in temperature, pH and the use of surfactants. Since dyeing process is a mix of all these parameters, we pretended to study each one separately. Changes in pH at constant temperature induce a release of dye similar with changes in temperature. In acid conditions we found a very fast initial dye release which doesn’t occur in basic conditions. Using carboxyfluorescein, as a pH fluorescence probe, we concluded that the liposome membrane doesn’t protect the liposome interior from changes on the external pH

El factor cultural: una nueva estrategia impulsada por EEUU en Afganistán

Barak Obama envió a Afganistán a uno de sus mejores generales, Stanley McChrystal, quien en su primer informe solicitó al presidente el envío de más tropas para proporcionar seguridad pero, sobre todo, un cambio de rumbo en la estrategia que tenga en cuenta el “entorno humano”. El análisis de las recientes operaciones militares internacionales ha puesto de relieve la falta de un conocimiento suficiente del “entorno humano” y de sus principales características socio-culturales. Al evaluar la misión de ISAF en Afganistán, el mando aliado ha subrayado que la situación es grave y que, a pesar de ciertos progresos, muchos indicadores sugieren que la situación general se está deteriorando, con un aumento de las acciones de los insurgentes y una crisis de confianza de los afganos en sus instituciones y en la comunidad internacional. Se señala, por consiguiente, la necesidad de “redefinir el combate” y se propone una nueva estrategia que ponga el acento en la población. Este análisis describe como el mando aliado pretende desplazar el centro de gravedad de la operación militar, que hasta ahora había sido desarticular el movimiento talibán y en adelante será ganarse a la población local mediante una mayor interacción cultural, y se plantea qué puede aportar España, presente en la ISAF, al nuevo enfoque estratégico

Dynamical Evolution of an Unstable Gravastar with Zero Mass

Using the conventional gravastar model, that is, an object constituted by two components where one of them is a massive infinitely thin shell and the other one is a de Sitter interior spacetime, we physically interpret a solution characterized by a zero Schwarzschild mass. No stable gravastar is formed and it collapses without forming an event horizon, originating what we call a massive non-gravitational object. The most surprise here is that the collapse occurs with an exterior de Sitter vacuum spacetime. This creates an object which does not interact gravitationally with an outside test particle and it may evolve to a point-like topological defect.Comment: 8 pages, 10 figures, to appear in Astrophysics and Space Scienc

The application of microcapsules of PCM in flame resistant non-woven materials

The use of organic microcapsules of phase change materials (mPCM) has been gaining ground in technical textiles for temperature regulation and hence a means of keeping the body at a comfortable temperature when wearing impermeable protective clothes. However, for such applications as fire-fighter’s protective clothes, the standards require that all the material composing the material be fire resistant, including the lining made of aramid fibres. Organic PCM such as n-octadecane are the most used in textiles, since they are easily microencapsulated in Melamine-formaldehyde (MF) polymers. Paraffins such as n-octadecane however, are flammable and ignite easily. Even though they are microencapsulated, the microcapsules are porous and at high temperatures the paraffin will vaporize and diffuse through the pores. As the application of mPCM is usually through the use of binder applied on the fibres by padding or coating and binders are thermoplastic and inevitably flammable such applications increase the flammability of the material. Based on a new approach where MF microcapsules of n-octadecane were treated with different flame retardant products, either co-polymerised on the surface or attached by ion-exchange, as was the case with Zinc and Boron, it was possible to make flame-retardant microcapsules of n-octadecane. For application on the aramid non-woven, flame retardant and MF resin were applied instead of binder and the material containing the flame retardant microcapsules was then also resistant for example to the standard flame propagation test EN532

Colored nanoparticles for ecological dyeing of cellulosic fibers

Dyeing cellulosic fibres with reactive dyes wastes great quantities of salt and water. The objective of this work is to dye cellulosic fibers using colored nanoparticles (CNPs) as an alternative to dyeing with reactive dyes. CNPs do not need salt nor soaping after dyeing, consuming less than 50% of water