Sulfobetaine-Siloxanes: A Class of Self-Destructive Surfactants.

The hydrolytic susceptibility of sulfobetaine-siloxane surfactants is investigated by comparison of a homologous series in this subclass of surfactants (R-(CH)N(Me)(CH)SO; R = (MeSiO)Si-, (MeSiO)Si(Me)-, (MeSiO)-Si(Me)-) with an analogue series of oxyethylene-siloxane surfactants (R-(CH)(OCHCH)OH; R = (MeSiO)Si-, (MeSiO)Si(Me)-, (MeSiO)-Si(Me)-). Nuclear magnetic resonance (NMR) monitoring of these surfactants in an aqueous solution shows that the presence of the sulfobetaine head structure greatly enhances the hydrolysis rate of the siloxane tail as compared with oxyethylene-siloxane analogue control experiments. This sulfobetaine effect is confirmed by adding a model compound, (Me)N(CH)SO, to the oxyethylene-siloxane surfactants and observing the large hydrolysis enhancement.

The Effect of Copper Addition on the Activity and Stability of Iron-Based CO₂ Hydrogenation Catalysts.

Iron-based CO₂ catalysts have shown promise as a viable route to the production of olefins from CO₂ and H₂ gas. However, these catalysts can suffer from low conversion and high methane selectivity, as well as being particularly vulnerable to water produced during the reaction. In an effort to improve both the activity and durability of iron-based catalysts on an alumina support, copper (10-30%) has been added to the catalyst matrix.

Continuous flow, explosives vapor generator and sensor chamber.

A novel liquid injection vapor generator (LIVG) is demonstrated that is amenable to low vapor pressure explosives, 2,4,6-trinitrotoluene and hexahydro-1,3,5-trinitro-1,3,5-triazine. The LIVG operates in a continuous manner, providing a constant and stable vapor output over a period of days and whose concentration can be extended over as much as three orders of magnitude. In addition, a large test atmosphere chamber attached to the LIVG is described, which enables the generation of a stable test atmosphere with controllable humidity and temperature.

Mitigation of TNT and Destex explosion effects using water mist.

The effects water mist has on the overpressures produced by the detonation of 50 lb equivalent of high explosives (HE) TNT and Destex in a chamber is reported. The overpressures for each charge density were measured with and without mist preemptively sprayed into the space. A droplet analyzer was placed in the chamber prior to the detonation experiments to characterize the water mist used to mitigate the explosion overpressures.