No description available.

Computational simulations of air glow discharge plasma in the presence of supersonic flow are presented. The glow discharge model is based on a self-consistent, multi-species, continuum description of the plasma with finite-rate chemistry effects. The glow discharge model is coupled to a compressible Navier-Stokes solver to study the effect of the plasma on the flow and the counter-effect of the flow on the plasma. A finite-rate air chemistry model is presented and validated against experiments from the literature at a pressure of 600 mTorr. Computational results are compared with experimentally measured V-I characteristics, axial positive ion densities and electron temperature, and reasonably good qualitative and quantitative agreement is observed. The validated air plasma model is then used to study the effect of the surface plasma discharge on M=3 supersonic flow at freestream pressure 18 Torr and the corresponding effects of the flow on the discharge structure in two dimensions. The species concentrations and the gas temperature are examined in the absence and presence of bulk supersonic flow. The peak gas temperature from the computations is found to be 1180 K with the surface plasma alone in the absence of flow, and 830 K in the presence of supersonic flow. Results indicate that O- ions can have comparable densities to electrons in the pressure range 1-20 Torr, and that O2- ion densities are at least two orders of magnitude smaller over the pressure range considered. Different ion species are found to be dominant in the absence and presence of supersonic flow, highlighting the importance of including finite-rate chemistry effects in discharge models for understanding plasma actuator physical phenomena. Electrode polarity effects are investigated, and the cathode upstream actuation is found to be stronger than the actuation strength with the cathode downstream, which is consistent with experimental findings of several groups. A parallel computing implementation of the plasma and flow simulation tools has been developed and is used to study the three-dimensional plasma actuator configuration with circular pin electrodes. / text

Graduation date: 1998

A static electrochemical discharge machining (ECDM) tester, where the tungsten needle is used as the cathode and the platinum as the anode and the glass as the specimen, and the depth of electrode is set to be 1mm in the aqueous electrolyte of 30wt% KOH at the test time of 10s, is employed to investigate the influence of geometry and size of the electrode, supply voltage and gap on the characteristic of electrochemical discharge machining. According to the current/voltage measurements combined with the photographs of the bubble layer on the cathode and the behavior of discharge under different geometry and size of the electrode during the ECDM process, three regimes have been identified as: (I): non-machining. (II): glow discharge. (III): spark discharge. From the observation on the surface of machined glass specimen by using SEM, the experimental result show that damage of the glass increases with the increase of supply voltage.

Syftet med studien var att undersöka vad känslor spelar för roll för beslutet att donera pengar till välgörande ändamål. Dessutom undersöktes om motivet ”social signaling” (publikt/anonymt) har någon påverkan på beslutet att ge pengar till en välgörenhetsorganisation. I ett experiment fick försökspersoner fatta ekonomiska beslut om donation till Rädda Barnen. Resultaten visade att generellt är människor generösare när de fattade besluten publikt än anonymt. Positiva/negativa känslor styrde hur personer fattar donationsbeslut. Känslor påverkades dock inte av att de fattade beslutet publikt eller anonymt. Överlag kände de sig positivare när de förlorade mindre pengar och välgörenhetsorganisationen fick mer pengar, dock inte när de både förlorade mer och välgörenhetsorganisationen fick mer. Sammantaget visar studien att både känslor och sociala motiv påverkar donationsbeteende.

Thesis (Ph. D.)--West Virginia University, 2004. / Title from document title page. Document formatted into pages; contains xvi, 193 p. : ill. Vita. Includes abstract. Includes bibliographical references.

No description available.

Thesis (Ph. D.)--University of Missouri-Columbia, 2007. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on February 25, 2008) Vita. Includes bibliographical references.

Thesis (Ph. D.)--University of Adelaide, Dept. of Applied Mathematics, 1994? / Includes bibliographical references (leaves 211-216).

Thesis (Ph. D.)--West Virginia University, 2000. / Title from document title page. Document formatted into pages; contains xv, 161 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 153-157).