Thomas W. Kenny

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Geckos are exceptional in their ability to climb rapidly up smooth vertical surfaces. Microscopy has shown that a gecko's foot has nearly five hundred thousand keratinous hairs or setae. Each 30-130 microm long seta is only one-tenth the diameter of a human hair and contains hundreds of projections terminating in 0.2-0.5 microm spatula-shaped structures.(More)
Geckos have evolved one of the most versatile and effective adhesives known. The mechanism of dry adhesion in the millions of setae on the toes of geckos has been the focus of scientific study for over a century. We provide the first direct experimental evidence for dry adhesion of gecko setae by van der Waals forces, and reject the use of mechanisms(More)
In this paper, we make a brief study of some of the important requirements of a structural monitoring system for civil infrastructures and explain the key issues that are faced in the design of a suitable wireless monitoring strategy. Twotiered wireless sensor network architecture is proposed as a solution to these issues and the protocol used for the(More)
Piezoresistive cantilevers are limited by two major noise sources: Johnson noise, which is independent of frequency, and conductance fluctuation noise, which has a 1/f spectrum. The 1/f fluctuations of piezoresistive cantilevers are shown to vary inversely with the total number of carriers in the piezoresistor, as formulated by F.N. Hooge [Phys. Rev. Lett.,(More)
Noncontact friction between a Au(111) surface and an ultrasensitive gold-coated cantilever was measured as a function of tip-sample spacing, temperature, and bias voltage using observations of cantilever damping and Brownian motion. The importance of the inhomogeneous contact potential is discussed and comparison is made to measurements over dielectric(More)
Magnetic resonance force microscopy was used to study the behavior of small ensembles of unpaired electron spins in silica near a micrometer-size ferromagnetic tip. Using a cantilever-driven spin manipulation protocol and a magnetic field gradient greater than 10(5) T/m, signals from as few as 100 net spins within a 20 nm thick resonant slice could be(More)
Chip-based microcolumn separation systems often require serpentine channels to achieve longer separation lengths within a compact area. However, analyte bands traveling through curved channels experience an increased dispersion that can reduce the benefit of increased channel length. This paper presents analytical solutions for dispersions, numerical models(More)
iii I certify that I have read this dissertation and that in my opinion it is fully adequate, in scope and quality, as a dissertation for the degree of Doctor of Philosophy. I certify that I have read this dissertation and that in my opinion it is fully adequate, in scope and quality, as a dissertation for the degree of Doctor of Philosophy. I certify that(More)
Two-phase forced convective flow in microchannels is promising for the cooling of integrated circuits. There has been limited research on boiling flow in channels with dimensions below 100 m, in which bubble formation and flow regimes can differ from those in larger channels. This work develops single and multichannel experimental structures using(More)