A microfabricated thermopneumatic actuator is being developed for low pressure, commercial valve and regulator applications. Using a microfabricated normally open valve as the actuator and a piezo-resistive pressure sensor for feedback, a closed-loop pressure regulator controlling up to 100 psi has been demonstrated. Normally closed operation has been demonstrated. It is anticipated that this actuation concept is capable of controlling fluids at pressures up to and possibly exceeding 3000 psi. During the Phase I stage of this proposal, the performance envelope of this actuation technology will be reported, designs for extension of that performance envelope will be explored, and a pressure regulator suitable for controlling 100 psi nitrogen supply will be delivered to the end-user for evaluation and verification of the actuation concept.Anticipated benefits/potential applications:Miniaturization and integration of valve function will lead to capabilities not presently available. Microfabricated valves and integrated electrofluidic circuits (IEFC's) have commercial applications in the automotive, biomedical, medical, process control, analytical chemistry and industrial sectors as well as government applications in the defense, energy, and environmental sectors.