Johns Hopkins University
Publishes on Ultrasonics and Acoustic Wave Propagation, Mechanical Behavior of Composites, Advanced Fiber Optic Sensors. 7 papers and 1.3k citations.
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Arrays of ferromagnetic nickel and cobalt nanowires have been fabricated by electrochemical deposition of the metals into templates with nanometer-sized pores prepared by nuclear track etching. These systems display distinctive characteristics because of their one-dimensional microstructure. The preferred magnetization direction is perpendicular to the film plane. Enhanced coercivities as high as 680 oersteds and remnant magnetization up to 90 percent have also been observed.
Resonant ultrasound spectroscopy is the study of spectra obtained by forced mechanical resonance of samples by swept frequency excitation. A novel apparatus is used to measure the amplitude/frequency resonance spectrum of a right rectangular parallelepiped specimen of AS4/3501-6 carbon epoxy composite material ([0, 60, 120] 192 lay-up) at 1 °C intervals between −177 °C and 25 °C. It is important to know the mechanical properties of this material at low temperatures for underwater, polar and space applications. The spectra indicate increasing stiffness with decreasing temperature and phase transitions. The damping decreases slightly with decreasing temperature. Analysis of the resonance spectrum, calculation of theoretical resonance spectrum, and computation of elastic stiffness tensor will be discussed.