Thesis (M.S.)--University of Wisconsin--Madison, 1963. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 92-95).

Thesis (M.S. in mechanical engineering)--Washington State University, December 2006. / Includes bibliographical references (p. 52-53).

Thesis (Ph. D.)--Oregon State University, 2008. / Printout. Includes bibliographical references. Also available on the World Wide Web.

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This thesis describes the transport properties observed in thermally treated graphite oxide (GO), which holds promise as an economical route to obtaining graphene. Graphene is a material consisting of a single atomic plane of carbon atoms and was first isolated as recently as 2004. Several isolation techniques have been investigated, including mechanical exfoliation, chemical vapor deposition, and the reduction (by various methods) of chemically synthesized graphite oxide. Two fundamental questions are pursued in this work. The first is concerned with the maximum electrical conductivity that can be achieved in atomically thin reduced graphite oxide samples (rGO). As produced, GO is insulating and of little use electronically. By heating and exposure to reducing atmospheres, however, the conductivity can be increased. Through the lithographic definition and fabrication of four-point contact structures atop microscopic samples of GO, the resistance of the sample can be monitored in situ as the reduction process takes place. It was discovered that the resistance of few-layer GO could be decreased by an order of magnitude when heated to 200 °C and subsequently cooled back to room temperature in forming gas. Final resistivities were on the order of 0.5 Ω-cm. An ambipolar field effect was observed in the thermally treated samples, with resistance decreasing by up to 16 % under a substrate bias of ±20 V. Mobilites were inferred to be on the order of 0.1 cm²/V-s. It was also found that the presence of forming gas during reduction decreased the resistance of the GO samples by roughly one half. The second question that this work begins to answer is concerned with the distance that electrons can travel in such thermally-reduced GO before spin-randomizing scattering. The answer can be elucidated with the aid of magnetoresistance measurements using ferromagnetic contacts to inject a spin-polarized current through the sample. The observation of the magnetoresistive effect with the contacts separated by a certain distance can be taken as evidence of a spin coherence length in the material of at least that distance. Though this experiment has not yet been carried out, progress has been made toward its possibility; specifically in the fabrication and characterization of independently switchable magnetic contacts. By exploiting magnetic shape anisotropy, contact pairs have been fabricated and demonstrated to differ in magnetic coercivity by up to 8 Oe. / Graduation date: 2011

Les objectifs de la thèse sont d'étudier le transport de fluide et le transfert de chaleur dans les pores micro et nanométriques. Les expériences et les simulations ont révélé des preuves de l'augmentation du flux provoquée par la vitesse de glissement à la paroi solide. D'autre part, la résistance thermique finie à l'interface fluide-solide est responsable de la différence de température des deux phases. Ces deux phénomènes d'interface peuvent avoir un impact considérable sur la perméabilité et la diffusivité thermique des milieux poreux constitués de micro et nanopores. La contribution se concentre sur l'étude des trois problèmes suivants. Premièrement, nous examinons les effets de glissement des liquides confinés dans un canal de graphème en utilisant le formalisme de Green Kubo et la méthode de la dynamique moléculaire. On montre que lorsque la surface solide est soumise à une contrainte mécanique uniaxiale, la friction présente une anisotropie due à la modification de l'énergie potentielle et de la dynamique des molécules composant le fluide. Les formes moléculaires jouent également un rôle important sur les écarts de frottement entre les deux directions principales. Deuxièmement, nous étudions le régime des gaz raréfiés. Dans ce cas, la vitesse de glissement et le saut de température sont régis par les collisions entre les atomes de gaz et la paroi solide. Ces effets peuvent être déterminés à l’aide d’un modèle statistique qui peut être construit à partir des vitesses incidente et réfléchie des molécules de gaz. A cette fin, différentes méthodes basées sur des techniques d'apprentissage statistique ont été proposées. Enfin, la méthode des éléments finis est utilisée pour calculer la perméabilité et la diffusivité thermique des milieux poreux sous l'influence des effets d'interface / The objectives of the thesis are to study the fluid transport and heat transfer in micro and nano-scale pores. Both experiments and simulations revealed evidence of an enhancement of flow-rate, originated from slip velocity at the solid boundary. On the other hand, the finite thermal resistance at the fluid-solid interface is responsible for the temperature difference between the two phases. These two interface phenomena can have a considerable impact on the permeability and thermal diffusivity of porous media constituted of micro and nano-pores. This contribution focuses on studying the following three issues. First, we examine the slip effects of liquids confined in graphene channel using Green Kubo formalism and Molecular Dynamics method. It is shown that when the solid surface is subject to mechanical uniaxial strain, the friction exhibits anisotropy due to the modification of the potential energy and the dynamics of the fluid molecules. The molecular shapes also play an important factor on the friction discrepancies between two principal directions. The quantification of both effects is addressed. Second, we investigate the rarefied gas regime. In this case, the velocity slip and temperature jump are governed by the collisions between the gas and the solid boundary. Those effects can be determined via the study of scattering kernel and its construction from MD simulation data. To this end, different methods based on statistical learning techniques have been proposed including the nonparametric (NP) kernel and Gaussian mixture (GM) kernel. Finally, the finite element method is used to compute the permeability and the thermal diffusivity of porous media under the influence of the interface effects