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A new technique particularly suitable for fabricating uniform, hollow silica spheres of controlled size and porosity is described. The technique, which combines sol-gel processing with a hollow-drop generation technique, consists of producing a continuous stream of uniform, hollow drops of a tetraethyl orthosilicate solution and then converting the drops into a rigid form by exposing them to an ammoniated vapor gelation medium. The parameters controlling the properties of the resulting silica spheres are the detailed chemical makeup of the reactant solution and the gelation medium, and the dimensions and relative positions of the nozzles used for drop generation. [

A study of the reforming rates, heat transfer and flow through a methanol reforming catalytic microreactor fabricated on a silicon wafer are presented.Comparison of computed and measured conversion efficiencies are shown to be favorable. Concepts for insulating the reactor while maintaining small overall size and starting operation from ambient temperature are analyzed.