Three procedures allowing the systematic determination of the propagation characteristic of lines and deembedding the influence of feeding discontinuities are presented. All of them are based on the known measurement technique of two lines with different lengths on the measured substrate after earlier calibration with standard substrate. The first one doesn’t involve the knowledge of the refere...

In the design of modern accelerators, an accurate estimate of coupling impedance is very important. The sources which give rise to coupling impedance are the geometric discontinuities in the accelerator beam pipe. In various discontinuities such as RF cavities, bellows, and collimators, the coupling impedance of the holes has not been well understood. Although coupling impedance can be obtained...

A THEORY OF COCHLEAR INPUT IMPEDANCE AND MIDDLE EAR PARAMETER ESTIMATION by SUNIL PURIA Advisers: Professor Nenad M. Marinovic and Dr. Jont B. Allen In this thesis it is hypothesized that the geometry of the cat cochlea has evolved to maximize sound transmission from the eardrum to the cochlea. This hypothesis is shown to be tenable by modeling the cochlear input impedance and the middle-ear. I...

A method for calculating coupling impedances and power losses for off-axis beams is developed. It is applied to calculate impedances of small localized discontinuities like holes and slots, as well as the impedance due to a finite resistivity of chamber walls, in homogeneous chambers with an arbitrary shape of the chamber cross section. The approach requires to solve a two-dimensional electrost...

non-destructive eddy current (ec) technique has long been used to detect discontinuities in materials. recently, its application has been extended to characterize materials microstructure. in order to identify different microstructures, four plain carbon steel bars with different chemical compositions (aisi 1015, 1035, 1045 and 1080) were used in annealed condition. the pearlite percentage, car...

SS precursors are the underside reflections from the upper mantle discontinuities (400 and 670 primarily) at half distance. They have almost identical ray paths as SS except in the vicinity of the bounce point; therefore their differential travel times (with reference to SS) and amplitudes provide ideal constraints on the discontinuity topography and the impedance contrast across it. They have ...

A method for the simulation of discontinuities in photonic crystal defect waveguides is presented. This frequency domain technique is based on the multiple multipole method. In contrast with other known techniques, spurious reflections (due to the impedance mismatch at the waveguide terminations) are avoided. The absence of spurious reflections allows one to characterize precisely the intrinsic...

Non-destructive Eddy current (EC) technique has long been used to detect discontinuities in materials. Recently, its application has been extended to characterize materials microstructure. In order to identify different microstructures, four plain carbon steel bars with different chemical compositions (AISI 1015, 1035, 1045 and 1080) were used in annealed condition. The pearlite percentage, car...

Grazing flows and high acoustic intensities impose unusual design requirements on acoustic liner treatments used in aircraft engine nacelles. Increased sound absorption efficiency (requiring increased accuracy of liner impedance specification) is particularly critical in the face of ever decreasing nacelle wall area available for liner treatments in modern, high-bypass ratio engines. This paper...