Flight testing of a luminescent surface pressure sensor

NASA ARC has conducted flight tests of a new type of aerodynamic pressure sensor based on a luminescent surface coating. Flights were conducted at the NASA ARC-Dryden Flight Research Facility. The luminescent pressure sensor is based on a surface coating which, when illuminated with ultraviolet light, emits visible light with an intensity dependent on the local air pressure on the surface. This technique makes it possible to obtain pressure data over the entire surface of an aircraft, as opposed to conventional instrumentation, which can only make measurements at pre-selected points. The objective of the flight tests was to evaluate the effectiveness and practicality of a luminescent pressure sensor in the actual flight environment. A luminescent pressure sensor was installed on a fin, the Flight Test Fixture (FTF), that is attached to the underside of an F-104 aircraft. The response of one particular surface coating was evaluated at low supersonic Mach numbers (M = 1.0-1.6) in order to provide an initial estimate of the sensor's capabilities. This memo describes the test approach, the techniques used, and the pressure sensor's behavior under flight conditions. A direct comparison between data provided by the luminescent pressure sensor and that produced by conventional pressure instrumentation shows that the luminescent sensor can provide quantitative data under flight conditions. However, the test results also show that the sensor has a number of limitations which must be addressed if this technique is to prove useful in the flight environment

EXTENDED HUCKEL CALCULATIONS ON TRANSITION METAL PORPHYRINS.

Author Institution: Conant Chemical Laboratory, Harvard UniversityAn extension of the one electron Wolfsberg-Helmholtz model has been developed in an attempt to better understand the ground state electronic structure of the metal porphyrins and metal porphyrin complexes. In this discussion we present the model and use it to order the d orbital energies with respect to the pi to account for the ground state magnetic properties, to show that the coupling of the metal orbitals to the pi system is weak in agreement with the spectra, to seek the effects of the known non-planarity of the ring, and to examine the effects of ligands on the ring