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

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Thesis (Ph. D.)--Ohio State University, 2003. / Title from first page of PDF file. Document formatted into pages; contains xix, 207 p.; also includes graphics (some col.) Includes bibliographical references (p. 182-193). Available online via OhioLINK's ETD Center

Thesis (Ph. D.)--University of Washington, 1999. / Vita. Includes bibliographical references (leaves 140-144).

Thesis (Ph. D.)--University of Texas at Austin, 2008. / Vita. Includes bibliographical references.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1993. / Vita. Abstract. Includes bibliographical references (leaves 84-85). Also available via the Internet.

Thesis (Ph. D.) -- Virginia Commonwealth University, 2004. / Title from title-page of electronic thesis. Prepared for: Dept. of Chemistry. Bibliography: p. 218-236.

If a metal object is placed in a gravitational field, .the nuclei and electrons in the metal will sink. This will produce a new charge distribution inside the metal. A modified charge distribution implies a modified electric field in the metal interior. This thesis investigates some possible physical processes which give rise to the gravitationally induced electric field inside a metal. To this end, a simple model of a metal is constructed. Comprising the model are ions, arranged on a differentially compressed lattice, and a gas of conduction electrons. An ion is represented by a nucleus and an electron which are confined together inside a hard, massless, spherical shell. The nucleus is treated as a point particle while the electron is represented by a wave function. The conduction electron constituent is modelled as a gas of non-interacting fermions which is subject to an external linear potential, The design of the model facilitates the investigation of two possible sources of the electric field: gravitationally induced ionic dipole moments, and the charge imbalance in the metal. To first order in g, only the first source matters, contributing approximately –Mg/q[sub=e] to the electric field, where M is the ionic mass, g is the acceleration due to gravity, and q[sub=e] is the electronic charge. The net gravitationally induced electric field is also found to be approximately -Mg/q[sub=e], / Science, Faculty of / Physics and Astronomy, Department of / Graduate

Bioelectric fields are involved in patterning during embryonic development and play roles in regenerative growth and wound healing. Planaria are flatworms capable of regenerating whole new intact organisms from tiny portions of tissue, owing to a widespread population of adult somatic stem cells known as neoblasts. Previous research has suggested that an endogenous bioelectric field may contribute to the control of axial polarity and regenerative fate during planarian regeneration. By establishing novel techniques, we further investigated this hypothesis in experimentally relevant planarian species Dugesia japonica and Schmidtea mediterranea. Techniques were developed to measure transepithelial potential (TEP), record epithelial ion transport and apply exogenous electric fields to test the hypothesis that an endogenous electrical gradient contributes to axial regenerative polarity in planaria. We found that in the mesenchymal spaces of Dugesia japonica and Schmidtea mediterranea, a voltage gradient exists such that the head region is more negative than the tail. Importantly, this voltage gradient is maintained in regenerating amputated tissue fragments. Disrupting this endogenous electric field by means of exogenous DC electric field application induced regenerative anomalies affecting the anteroposterior axis. Reversal of the TEP gradient and regenerative polarity was achieved by application of an electric field that opposed the direction of the worm's natural electrical polarity, suggesting that the natural electrical gradient contributes to the control of polarity establishment during planarian regeneration.

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