Browsing by Subject "Fluid"

Now showing 1 - 5 of 5
  • Thumbnail Image
    Item
    Construction and characterization of a high performance supercritical fluid chromatography system
    (2013-08) Bodnia, Logan Walter
    The goal of this project is to design and build an Supercritical Fluid Chromatography instrument capable of doing fast separations with short columns packed with small particles. In order to do that the system must be capable of withstanding high pressures, have limited extra column effects, and be able to acquire data at a sufficient rate.
  • Thumbnail Image
    Item
    Hydrodynamics of strongly coupled non-conformal fluids from gauge/gravity duality.
    (2009-08) Springer, Greggory Todd
    The subject of relativistic hydrodynamics is explored using the tools of gauge/gravity duality. A brief literature review of AdS/CFT and gauge/gravity duality is presented first. This is followed by a pedagogical introduction to the use of these methods in determining hydrodynamic dispersion relations, w(q), of perturbations in a strongly coupled fluid. Shear and sound mode perturbations are examined in a special class of gravity duals: those where the matter supporting the metric is scalar in nature. Analytical solutions (to order q4 and q3 respectively) for the shear and sound mode dispersion relations are presented for a subset of these backgrounds. The work presented here is based on previous publications by the same author [1], [2], and [3], though some previously unpublished results are also included. In particular, the subleading term in the shear mode dispersion relation is analyzed using the AdS/CFT correspondence without any reference to the black hole membrane paradigm.
  • Thumbnail Image
    Item
    Monte Carlo Simulations for Multicomponent Phase Equilibria and Thermophysical Properties of Near-Critical Fluids
    (2014-09) Cortes Morales, Angel
    Understanding phase equilibria and thermophysical properties of complex fluid mixtures is crucial to the oil and gas industry, particularly for exploration and production process design. Crude oil and natural gases in such processes are subjected to a very broad range of conditions, under which experimental measurement of physical properties can be quite challenging. To overcome this, the industry has made extensive use of traditional thermodynamic models, such as equations of state and activity coefficient models. However, these conventional tools often lack the necessary predictive power to accurately model fluid properties across the entire range of relevant conditions, especially at extreme conditions where experimental data is often limited. Hence, Monte Carlo simulations have been employed to determine the microscopic features required for improving current PVT modeling methods. Results have shown that these simulations provide remarkably accurate descriptions of phase equilibria and thermophysical properties of fluids relevant to petroleum processing across a wide range of conditions, showing the versatility of molecular simulations as a predictive modeling tool and for developing new modeling methods.
  • Thumbnail Image
    Item
    Reconfigurable passive RF circuits leveraging integrated fluidic structures
    (2015-01) Murray, Casey Edward
    The demand for wireless capability in our everyday life is continually increasing. This demand is creating the need for multi-band systems and systems that can be changed to adapt to their environment. Many research groups are looking into ways to meet these needs. One area in particular, is incorporation of fluidics in RF design to change the circuit's characteristics by leveraging conductive, magnetic, or dielectric properties of the fluid. The work presented focuses on leveraging the dielectric properties of fluids and how fluids may be integrated into fundamental RF structures providing control over their characteristics. Ultimately, providing design concepts that could be refined for particular applications.Fluids are integrated into four fundamental structures in this work: 1) a transmission line, 2) a directional coupler, 3) an annular slot antenna, and 4) a band-pass filter. The transmission line focuses on the use of the dielectric properties of fluids to create a tunable delay line. The directional coupler work demonstrates how fluids can be used to vary coupling and isolation in a microstrip structure. Fluids are next integrated into antenna structures demonstrating the possible tuning range. Lastly, a fluidic channel is integrated into a microstrip ring band-pass filter demonstrating the change in pass-band characteristics.
  • Thumbnail Image
    Item
    Relativistic Fluids of Topological Defects
    (2015-09) Schubring, Daniel
    A number of papers on the topic of string fluids written by Vitaly Vanchurin and myself are reviewed. A network of Nambu-Goto strings is coarse-grained and the equations for a generalized fluid are derived. Besides the symmetric energy-momentum tensor, the fluid also has a conserved antisymmetric tensor $F$ related to the topological flux of strings. This $F$ tensor obeys the homogeneous Maxwell equations, and there is a topological constraint similar to Gauss's law for magnetism. The fluid is isentropic and pressureless and foliated by two-dimensional submanifolds which can be considered to be worldsheets of macroscopic strings. The macroscopic strings are shown to obey the known equations of motion of a wiggly string. The fluid can be generalized to have pressure and be foliated by arbitrary current carrying strings by introducing a natural variational principle. An action is constructed as a functional of three scalar fields which can be identified as the Lagrangian coordinates of the fluid. This same variational principle for a specific choice of functional is shown to lead to the equations of magnetohydrodynamics, in which the $F$ tensor above is indeed the electromagnetic tensor. Furthermore a minor modification in the fields varied leads to the equations for a model of vortices in a superfluid. The effect of dissipation can be introduced by allowing the $F$ tensor and energy-momentum tensor to depart from their equilibrium forms. The condition that entropy must increase restricts the form of the non-equilibrium components of these tensors, and leads to the analogue of the Navier-Stokes equations for a string fluid. Besides terms involving viscosity there are additional terms dependent on the curvature of the lines of flux. In the case of magnetohydrodynamics these additional terms are shown to be equivalent to Ohm's law and the thermoelectric Nernst effect. The condition that the non-equilibrium terms vanish is used to derive conditions for hydrostatic equilibrium that may be useful in astrophysical situations.