A wideband digital signal acquisition instrument intended primarily for ultrasonic experimentation has been designed and built. It comprises an integrated array of modules which combine to provide: a pulser for transducer excitation, wideband amplification (>80 MHz bandwidth), high speed sampling (>160 MHz), on-board memory (4K x 16 bits capacity), control hardware and real-time coherent averaging. The integration of the modules offers significant benefits over systems consisting of a number of separate items of equipment. The major benefit is a reduction in acquisition time which is accomplished as follows. The time relationship between the sampling clock and the input signal is controlled to minimise the signal repetitions required for interleaving. This is achieved by triggering the input signal using a pulser board locked to the sample clock. In addition, signal averaging is implemented in hardware using two memory modules and an adder module. Since the time relationship between the sampling clock and the input signal is controlled it cannot be tested using a sinewave because it is not possible to produce a sinewave which is correlated with the sampling clock. Instead, a rectangular pulse, triggered by the instrument, is applied to a single-pole low pass filter to provide the test signal. The time constant and start time is ascertained and used to reproduce the single-pole response. The reproduced response is then compared to the sampled signal to produce an error plot from which the system's linearity and effective bits can be deduced. As the system was designed for fast acquisition, and hence has a short aperture time, it is highly applicable to dynamic processes. The dynamic process application chosen was the measurement of absorption and velocity on rapidly flocculating and sedimenting colloids.

Thesis (M.S.) in Mechanical Engineering--University of Maine, 2002. / Includes vita. Includes bibliographical references (leaves 76-83).

Thesis (M.S. in civil engineering)--Washington State University, December 2009. / Title from PDF title page (viewed on Dec. 28, 2009). "Department of Civil and Environmental Engineering." Includes bibliographical references (p. 51).

Thesis (Ph.D.)--Tufts University, 2000. / Adviser: Masoud Sanayei. Submitted to the Dept. of Civil Engineering. Includes bibliographical references (leaves 152-159). Access restricted to members of the Tufts University community. Also available via the World Wide Web;

Thesis (Ph. D.)--University of Washington, 1997. / Vita. Includes bibliographical references (leaves [149]-153).

Thesis (M.S.)--Rowan University, 2006. / Typescript. Includes bibliographical references.

Ultrasonic velocity and attenuation measurements have been used to characterise a range of phosphate bonded, alumina filled, magnesia ceramics and other ceramic materials... Measurements were made over a range of frequency from 50kHz - 1 OM Hz, using a variety of commercial probes and equipment, and a variety of techniques. An ultrasonic double-probe method was used to monitor the setting process of the cementitious ceramics using commercial 2.25MHz and 2MHz transducers, for compressional and shear wave modes, respectively, in samples with alumina content in the range of 0 - 60 wt 0/0. The elastic properties of the material were determined from ultrasonic velocity measurements and were found to be dependent upon the filler volume fraction. The measured elastic moduli were found to Increase as porosity decreased, and this effect might possibly be used to estimate porosity. The composition dependence of the elastic moduli is compared with the Hashin and Shtrikman theoretical bounds for the elastic moduli of two-phase materials. All data lie between these bounds, suggesting that the alumina particles were well dispersed and well bonded to the matrix. However, the fact that the data are slightly above the lower bound suggested that the particles are not spherical, and this, together with other evidence obtained from an analysis of reaction rates, indicates the predominence of plate-like gram structures.

published_or_final_version / Electrical and Electronic Engineering / Master / Master of Philosophy

Thesis (M.S.)--University of Missouri--Rolla, 2007. / Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed November 14, 2007) Includes bibliographical references (p. 118-119)

Thesis (M.Sc.)--City University of Hong Kong, 2006. / "Master of Science in Materials Engineering & Nanotechnology dissertation." Title from title screen (viewed on Nov. 21, 2006) Includes bibliographical references.