Physical Sciences and Mathematics Commons^™

Factors Affecting Redox Magnetohydrodynamics For Flow In Small Volumes, Matthew D. Gerner

Graduate Theses and Dissertations

Lab-on-a-chip technologies offer the possibility of developing analytical devices that are low-cost, portable, disposable, fast, and operable by non-technical personnel. Such devices require automated methods to manipulate ultra-small volumes (picoliters) of samples and solution, including pumping, stirring, and positioning. Current methods for ultra-small volume microfluidics have limitations that restrict their use including high voltage requirements, disadvantageous flow profiles or rates, and relatively complicated fabrication due to mechanical parts. Redox magnetohydrodyanmics (RMHD) that utilizes permanent magnets for portability shows promise as a micropump with ease of switching flow direction, no moving parts, compatibility with both aqueous and non-aqueous solutions, low voltages …

An Experimental Study Of The Hydrodynamics Of Multiphase Flow In Fluidized Beds, Gerardo Vargas

Open Access Theses & Dissertations

Fluidized bed reactors have been widely used as a gasifier in coal gasification processes to convert coal into other forms of energy. At this stage, full fluidization is required to attain the best thermochemical reaction within the fluid-solid mixture. This can only be achieved if the fluid is maintained between minimum fluidization and terminal velocities. To better understand the hydrodynamics of multiphase flow, a fluidized bed was designed and constructed to carry out the investigation. Compressed air and 1-mm glass beads were used to determine gas minimum fluidization and terminal velocities at three different particle concentrations. The solids were enclosed …

Automated Network Planning For Industrial Ethernet Networks, Holger Machens

Theses

Engineers usually use computer aided methods to ease the increasingly complex planning task of automation plants. One such computer aided method for automated planning of Industrial Ethernet networks under given network QoS requirements is presented in this thesis. The method is based on partitioning the given set of network nodes according to specified communication relationships between the nodes, thereby creating subsets of nodes which are joined using given networking algorithms. Several networking algorithms may be applicable for each subset of nodes and any complete solution is a combination of several partial solutions, one for each subset of nodes. Enumeration through …

Employing The Spectral Collocation Method In The Modeling Of Laminar Tube Flow Dynamics, Corey Michael Thibeault

All Graduate Theses, Dissertations, and Other Capstone Projects

The spectral collocation method is a numerical approximation technique that seeks the solution of a differential equation using a finite series of infinitely differentiable basis functions. This inherently global technique enjoys an exponential rate of convergence and has proven to be extremely effective in computational fluid dynamics. This paper presents a basic review of the spectral collocation method. The derivation is driven with an example of the approximation to the solution of a 1D Helmholtz equation. A Matlab code modeling two fluid dynamics problems is then given. First, the classic two-dimensional Graetz problem is simulated and compared to an analytical …

Parametric Study Of Efficiency Measures For Home Energy Conservation In Las Vegas, Nevada, Todd M. France

UNLV Theses, Dissertations, Professional Papers, and Capstones

Pulte Homes, a production home builder and community developer partnering with the U.S. Department of Energy's Building America program, has collaborated with the Center for Energy Research at the University of Nevada, Las Vegas and NV Energy, the local electric utility, on an energy conservation project in the Las Vegas Valley.

This study entails four model homes at a new development in the Summerlin community of Las Vegas, Nevada, named Villa Trieste. The home models, ranging in floor plan area from 1,487 to 1,777 square feet, have been constructed under the Environments for Living program and are LEED (Leadership in …

Insight Into The Physics Of Rupture: Dynamic Triggering Seismicity, Hector Gonzalez-Huizar

Open Access Theses & Dissertations

Seismic waves can trigger earthquakes and tremor at large distances from the causable event. Dynamic triggering occurs when the surface waves from large earthquakes change the stresses conditions on previously overstressed faults, promoting failure. To understand the causative stresses and environments behind dynamic triggering, we model the change in the stress field that the passing of Rayleigh and Love waves cause on a fault plane of arbitrary orientation relative to the direction of propagation of the waves, and apply a Coulomb failure criterion to calculate the potential of these stress changes to trigger seismicity. We apply our model to three …

Optimization Of Solid Oxide Fuel Cell Interconnect Design, Krishna C. Pulagam

UNLV Theses, Dissertations, Professional Papers, and Capstones

Performance of solid oxide fuel cells (SOFC) is dependent of a set of complex physical and chemical processes occurring simultaneously. Interconnect for SOFC is important as it provides electrical connection between anode of one individual cell to the cathode of neighboring one. It also acts as a physical barrier to protect the air electrode material from the reducing environment of the fuel on the fuel electrode side, and it equally prevents the fuel electrode material from contacting with oxidizing atmosphere of the oxidant electrode side. A three-dimensional numerical model has been developed to evaluate the SOFC including the current collector, …

Empirically Derived Formulas To Predict Indoor Maximum, Average, And Minimum Temperatures In Roofpond Buildings Using Minimum Climatic Information, Ibrahim Kivarkis Kako

UNLV Theses, Dissertations, Professional Papers, and Capstones

This thesis introduces an empirically developed formula to predict the comfort conditions and thermal performance of a Skytherm(TM) Southwest Roofpond placed over a light-weight un-insulated structure built at the School of Architecture at the University of Nevada, Las Vegas.

The predictive formula introduced in this study may be used in different parts of the world (particularly developing nations where insulation and air-conditioning are rarely used) to predict the performance of a Skytherm(TM) Southwest Roofpond using minimal climate data.

The data collected in the experimental setup at the Natural Energies Advanced Technologies Laboratory included outside and inside temperatures of various surfaces …

Two-Tank Indirect Thermal Storage Designs For Solar Parabolic Trough Power Plants, Joseph E. Kopp

UNLV Theses, Dissertations, Professional Papers, and Capstones

The performance of a solar thermal parabolic trough plant with thermal storage is dependent upon the arrangement of the heat exchangers that ultimately transfer energy from the sun into steam. The steam is utilized in a traditional Rankine cycle power plant. The most commercially accepted thermal storage design is an indirect two-tank molten salt storage system where molten salt interacts with the solar field heat transfer fluid (HTF) through a heat exchanger. The molten salt remains in a closed loop with the HTF and the HTF is the heat source for steam generation. An alternate indirect two tank molten salt …

Optimization Of Channel Geometry In A Proton Exchange Membrane (Pem) Fuel Cell, Jephanya Kasukurthi

UNLV Theses, Dissertations, Professional Papers, and Capstones

Bipolar plates are the important components of the PEM fuel cell. The flow distribution inside the bipolar plate should be uniform. Non-uniform flow distribution inside the bipolar leads to poor performance of the fuel cell and wastage of expensive catalyst. A single channel PEM fuel cell is taken and electrochemical analysis is carried out on it. The results are compared with the available published experimental data obtained by other research group, and they are found to be in good agreement. A baseline design of the bipolar plate is taken and numerical analysis is carried out. The results show that the …

Experimental And Numerical Study Of A Proton Exchange Membrane Electrolyzer For Hydrogen Production, Sachin S. Deshmukh

UNLV Theses, Dissertations, Professional Papers, and Capstones

Hydrogen as a fuel source has received attention from researchers globally due to its potential to replace fossil based fuels for energy production. Research is being performed on hydrogen production, storage and utilization methods to make its use economically feasible relative to current energy sources. The PEM electrolyzer is used to produce hydrogen and oxygen using water and electricity. Focus of our study is to provide a benchmark experiment and numerical model of a single cell electrolyzer that can assist in improving the current state of understanding of this system. Parametric analysis of an experimental cell was performed to understand …