Now showing items 1-10 of 179
On the evanescent fields and the causality of the focus wave modes
(AIP Publishing, 1995-08-01)
The diverging and converging field components of the source-free focus wave modes are studied within the framework of both the Whittaker and Weyl plane wave expansions, It is shown that, in the Weyl picture, the evanescent ...
Characterization of multiple piezoelectric actuators for structural excitation
(Acoustical Society of America, 1991-07-01)
The thrust of the present work is to analytically and experimentally study the response of a simply supported beam driven by multiple piezoelectric actuators in an effort to understand distributed excitation of the structure. ...
Implications of noise on the reference signal in feedforward control of harmonic disturbances
(Acoustical Society of America, 1994-10-01)
The purpose of this Letter is to detail the effect of random (zero-mean) noise on the reference input of an adaptive feedforward filter in the control of single-frequency disturbance inputs. Results from this study indicate ...
Fiberoptic Temperature Sensors Based on Differential Spectral Transmittance Reflectivity And Multiplexed Sensing Systems
(Optical Society of America, 1995-07-01)
A concept for optical temperature sensing based on the differential spectral reflectivity/transmittance from a multilayer dielectric edge filter is described and demonstrated. Two wavelengths, lambda(1) and lambda(2), from ...
Fabry-Perot Fiber-Optic Sensors in Full-Scale Fatigue Testing on an F-15 Aircraft
(Optical Society of America, 1992-02-01)
We report results from fiber-optic-sensor field tests on an F-15 aircraft mounted within a full-scale test frame for the purpose of fatigue testing. Strain sensitivities of the order of 0.01 _m/m have been obtained.
Fast-Neutron Radiation Effects in A Silica-Core Optical-Fiber Studied By A Ccd-Camera Spectrometer
(Optical Society of America, 1994-05-01)
A simple CCD-camera spectrometer was deployed at the Los Alamos Spallation Radiation Effects Facility to characterize fast-neutron irradiation effects in several silica-based optical fibers over the wavelength range ...
Linear-Array Apertures For In-Flight Dynamic Solar Calibration Of Radiometric Channels For Earth Radiation-Budget Applications
(Optical Society of America, 1994-07-01)
The zero-frequency gain of nonimaging radiometers used in Earth radiation-budget applications is usually verified by a procedure that allows the instrument to view the Sun through an appropriate attenuating aperture and ...
Embedded-atom interatomic potentials for hydrogen in metals and intermetallic alloys
(American Physical Society, 1996-10-01)
Interatomic potentials of the embedded-atom type have been developed for H in metals. The potentials are constructed through a fitting procedure involving the thermodynamic heat of solution of H in the various metals and ...
Reactive ion etching of ferroelectric SrBi2TaxNb2-xO9 thin films
(AIP Publishing, 1996-01-01)
Ferroelectric SrBi2TaxNb2-xO9 thin films were patterned using reactive ion etching. Considering the environmental impact effect, CHCIFCF3, a special etching gas, known to be less environmentally hazardous compared to the ...
Modeling of distributed piezoelectric actuators integrated with thin cylindrical shells
(Acoustical Society of America, 1994-09-01)
The dynamic interaction between induced strain piezoelectric (PZT) actuators and their host structures is often ignored in the modeling of intelligent structures. A more realistic investigation of intelligent material ...