Abstract: A pulse detonation engine including one or more fuel injectors comprising one or more piezoelectric driving stacks wherein a flow control member of each injector is driven directly by the one or more piezoelectric stacks without additional amplification means or interposing elements while a flow area of the nozzle is variably adjustable to deliver controlled flow rates in a desired flow profile to improve engine performance and reduce emissions. The pulse detonation engine configured to support variable mission and operational requirements including delivery of required thrust using specific fuel types and with power and performance of the pulse detonation engine variably adaptable. The fuel injectors associated with the pulse detonation engine configure to deliver specified flow rates with minimal linear movement of the flow control member. The injector and drive electronics configured to deliver higher frequency operation and response with increased operational stability.

Abstract: An apparatus and method use a hybrid absorbing element defined by a novel implementation of perfectly matched layer and infinite element concepts to model time-domain and frequency domain wave propagation finite element calculations. The hybrid absorbing element comprises three or more semi-infinite facets providing an essentially reflectionless interface for outgoing waves. Perfectly matched layer conditions are coupled to finite-element wavefield computation regions and infinite element conditions, which effectively disperse advancing waves at infinity. The disclosed apparatus and method result in the rapid attenuation of waves arriving at arbitrary angles, leading to elimination of reflection artifacts.

Abstract: A fuel injector apparatus comprising a piezoelectric driving stack and injector assembly wherein a flow control member of the fuel injector apparatus is driven directly by the piezoelectric stack without additional amplification means or interposing elements while the flow area of the nozzle portion is variably adjustable to deliver controlled flow rates in a desired flow profile to improve engine performance and reduce emissions. The injector configuration is adapted to support required flow rates with minimal linear movement of the flow control member.

Abstract: A triangulated roof structure for supporting a roof that projects in plan a substantially closed curve includes a substantially horizontal outer compression ring, a plurality of tension hoops concentrically arranged within the compression ring at different heights relative to a common reference plane, and a plurality of substantially vertical compression members having upper and lower ends, affixed at their lower ends to each of the tension hoops. The compression members are located so that compression members affixed to a first tension hoop are not radially aligned with compression members affixed to an adjacent tension hoop. The structure also includes a plurality of tension elements interconnecting a compression member affixed to the first tension hoop to a proximal pair of compression members affixed to an adjacent tension hoop and means for securing an outermost tension hoop and the vertical compression members attached thereto to the compression ring.

Abstract: A triangulated cable dome roof having a retractable roof portion includes a triangulated cable arrangement for supporting a roof membrane, a roof membrane which is fixed to a portion of the triangulated cable arrangement so that a portion of the underlying area is exposed, and a retractable roof portion movably secured to the triangulated cable arrangement. The retractable roof portion preferably includes one or more retractable roof sections, each of which is movable between a closed position in which the retractable roof sections overlay the uncovered portion of the triangulated cable arrangement and an opened position in which the retractable roof sections nest above the covered portion of the triangulated cable arrangement, thereby exposing a portion of the underlying area.