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2010

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Articles 451 - 480 of 6945

Full-Text Articles in Physical Sciences and Mathematics

Synthesis Of Trimetallic Nitride Endohedral Metallofullerene Derivatives For Enhanced Solar Energy Conversion, Julio Pinzon Joya Dec 2010

Synthesis Of Trimetallic Nitride Endohedral Metallofullerene Derivatives For Enhanced Solar Energy Conversion, Julio Pinzon Joya

All Dissertations

The preparation and electrochemical properties of donor - acceptor systems based on trimetallic nitride endohedral metallofullerenes (TNT-EMFs) for enhanced solar energy conversion is described. It was found that TNT-EMFs have an enhanced ability to stabilize charge separated states formed upon light irradiation when compared to empty cage fullerene analogues. The influence of the linker connecting the donor and acceptor moieties was studied in two different systems. Optimal conditions for preparing cyclopropanated Bingel-Hirsch derivaties of the most common TNT-EMFs were found; this functionalization approach is a very useful alternative to the 1,3-dipolar cycloaddition reactions that yield pyrrolidine derivatives, because the latter …


Evolutionary Strategies For Data Mining, Rose Lowe Dec 2010

Evolutionary Strategies For Data Mining, Rose Lowe

All Dissertations

Learning classifier systems (LCS) have been successful in generating rules for solving classification problems in data mining. The rules are of the form IF condition THEN action. The condition encodes the features of the input space and the action encodes the class label. What is lacking in those systems is the ability to express each feature using a function that is appropriate for that feature. The genetic algorithm is capable of doing this but cannot because only one type of membership function
is provided. Thus, the genetic algorithm learns only the shape and placement of the membership function, and in …


Gravity Couplings In The Standard-Model Extension, Quentin G. Bailey Dec 2010

Gravity Couplings In The Standard-Model Extension, Quentin G. Bailey

Publications

The Standard-Model Extension (SME) is an action-based expansion describing general Lorentz violation for known matter and fields, including gravity. In this talk, I will discuss the Lorentz-violating gravity couplings in the SME. Toy models that match the SME expansion, including vector and two-tensor models, are reviewed. Finally I discuss the status of experiments and observations probing gravity coefficients for Lorentz violation.


Scattering Matrix Elements For The Nonadiabatic Collision B (2PJₐ) + H2 (1Σ+G, Ν, Ј) ↔ B (2PJ’ₐ) + H2 (1Σ+G, Ν’, J’), Luke A. Barger Dec 2010

Scattering Matrix Elements For The Nonadiabatic Collision B (2PJₐ) + H2 (1Σ+G, Ν, Ј) ↔ B (2PJ’ₐ) + H2 (1Σ+G, Ν’, J’), Luke A. Barger

Theses and Dissertations

Scattering matrix elements are calculated for the nonadiabatic inelastic collision B (2Pjₐ) + H2 (1Σ+g, ν, ј) ↔ B (2Pj’ₐ) + H2 (1Σ+g, ν’, j’). This calculation utilizes the effective potential energy surfaces for this collision generated by Garvin along with a correction to the asymptotic H2 potential. Wavepackets are propagated on these surfaces using a split-operator propagator. This propagation yields correlation functions between reactant and product Møller states which are used to calculate the scattering …


The Interaction Of Rock And Water During Shock Decompression: A Hybrid Model For Fluidized Ejecta Formation, Audrey Hughes Rager Dec 2010

The Interaction Of Rock And Water During Shock Decompression: A Hybrid Model For Fluidized Ejecta Formation, Audrey Hughes Rager

UNLV Theses, Dissertations, Professional Papers, and Capstones

Crater and ejecta morphology provide insight into the composition and structure of the target material. Martian rampart craters, with their unusual single-layered (SLE), double-layered (DLE), and multi-layered ejecta (MLE), are the subject of particular interest among planetary geologists because these morphologies are thought to result from the presence of water in the target. Also of interest are radial lines extending from the crater rim to the distal rampart of DLE craters. Exactly how these layered ejecta morphologies and radial lines form is not known, but they are generally thought to result from interaction of the ejecta with the atmosphere, subsurface …


Detention Basins For Phosphorus And Sediment Control In Clark County, Nevada, Amina Rashid Lodhi Dec 2010

Detention Basins For Phosphorus And Sediment Control In Clark County, Nevada, Amina Rashid Lodhi

UNLV Theses, Dissertations, Professional Papers, and Capstones

Nonpoint source urban stormwater runoff degrades aquatic ecosystems, and causes flooding. To mitigate its effects on natural and human environments best management practices (BMPs) became popular strategies to protect the integrity of water quality. Similarly, to mitigate the effects of stormwater quantity, detention basins (DBs) were put into place as flood control structures. Water quality control remains an unexplored and important aspect of DB utility, particularly, in arid regions. Since DBs are depressions in the earth and retain water over the course of several hours to days after a rain event, they can potentially act as BMPs. A key pollutant …


Dynamic Distributed Programming And Applications To Swap Edge Problem, Feven Z. Andemeskel Dec 2010

Dynamic Distributed Programming And Applications To Swap Edge Problem, Feven Z. Andemeskel

UNLV Theses, Dissertations, Professional Papers, and Capstones

Link failure is a common reason for disruption in communication networks. If communication between processes of a weighted distributed network is maintained by a spanning tree T, and if one edge e of T fails, communication can be restored by finding a new spanning tree, T’. If the network is 2-edge connected, T’ can always be constructed by replacing e by a single edge, e’, of the network. We refer to e’ as a swap edge of e.


The best swap edge problem is to find the best choice of e’, that is, that e which causes the new spanning …


Self-Stabilizing Leader Election In Dynamic Networks, Hema Piniganti Dec 2010

Self-Stabilizing Leader Election In Dynamic Networks, Hema Piniganti

UNLV Theses, Dissertations, Professional Papers, and Capstones

The leader election problem is one of the fundamental problems in distributed computing. It has applications in almost every domain. In dynamic networks, topology is expected to change frequently. An algorithm A is self-stabilizing if, starting from a completely arbitrary configuration, the network will eventually reach a legitimate configuration.

Note that any self-stabilizing algorithm for the leader election problem is also an algorithm for the dynamic leader election problem, since when the topology of the network changes, we can consider that the algorithm is starting over again from an arbitrary state. There are a number of such algorithms in the …


Evaluating The Energy And Carbon Footprint Of Water Conveyance System And Future Water Supply Options For Las Vegas, Nevada, Eleeja Shrestha Dec 2010

Evaluating The Energy And Carbon Footprint Of Water Conveyance System And Future Water Supply Options For Las Vegas, Nevada, Eleeja Shrestha

UNLV Theses, Dissertations, Professional Papers, and Capstones

Water production requires the use of energy to transport water from distant locations, pump groundwater from deep aquifers and treat water to meet stringent drinking water and wastewater regulations. Energy production based on its source involves the emission of greenhouse gases also known as carbon footprint, which is the leading cause of global warming and climate change. Because of growing concerns of global warming due to these emissions, water providers are required to analyze the energy and associated carbon footprint of existing water production facilities and future water supply options. A system dynamics model is developed to estimate the energy …


Carbon Isotopic Fractionation Across A Late Cambrian Carbonate Platform: A Regional Response To The Spice Event As Recorded In The Great Basin, Jonathan Lloyd Baker Dec 2010

Carbon Isotopic Fractionation Across A Late Cambrian Carbonate Platform: A Regional Response To The Spice Event As Recorded In The Great Basin, Jonathan Lloyd Baker

UNLV Theses, Dissertations, Professional Papers, and Capstones

Geochemical models have suggested that the late Cambrian was characterized by a greenhouse climate with high pCO2. Furthermore, stableisotope analyses within the Great Basin have documented a large carbonate isotope (δ13Ccarb) excursion, known as the Steptoean Positive Carbon Isotope Excursion (SPICE). This event has been documented globally, and is interpreted as having resulted from enhanced organic carbon burial. Unless the size of carbon reservoirs in the Cambrian ocean was significantly different from those of the Cenozoic, this forcing should have resulted in a comparable carbon-isotope excursion in organic matter (δ13Corg). It is also predicted that increased organic carbon burial would …


A Mathematical Approach For Optimizing The Casino Slot Floor: A Linear Programming Application, Kasra Christopher Ghaharian Dec 2010

A Mathematical Approach For Optimizing The Casino Slot Floor: A Linear Programming Application, Kasra Christopher Ghaharian

UNLV Theses, Dissertations, Professional Papers, and Capstones

Linear programming is a tool that has been successfully applied to various problems across many different industries and businesses. However, it appears that casino operators may have overlooked this useful and proven method. At most casino properties the bulk of gaming revenues are derived from slot machines. It is therefore imperative for casino operators to effectively manage and cultivate the performance of this department. A primary task for the casino operator is planning and deciding the mix of slot machines in order to maximize performance.


This paper presents the task of optimizing the casino slot floor as a linear programming …


Improving Ensemble Streamflow Prediction Using Interdecadal/Interannual Climate Variability, Kenneth W. Lamb Dec 2010

Improving Ensemble Streamflow Prediction Using Interdecadal/Interannual Climate Variability, Kenneth W. Lamb

UNLV Theses, Dissertations, Professional Papers, and Capstones

The National Weather Service’s (NWS) river forecast centers provide long-term water resource forecasts for the main river basins in the U.S. The NWS creates seasonal streamflow forecasts using an ensemble prediction model called the Extended Streamflow Prediction (ESP) software. ESP creates runoff volume forecasts by taking the current observed soil moisture and snowpack conditions in the basin and applying them to historical temperature and precipitation scenarios. The ESP treats every historic input year as a likely scenario of future basin conditions. Therefore improving the knowledge about how long-term climate cycles impact streamflow can extend the forecast lead time and improve …


A Study On Eco-Friendly Merchandise In A Resort Retail Environment, Lindsey C. Patrick Dec 2010

A Study On Eco-Friendly Merchandise In A Resort Retail Environment, Lindsey C. Patrick

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this study is to determine consumer purchasing habits of ecofriendly apparel in a retail resort environment. In order to find the rationale behind purchasing decisions, this study measured sales and survey responses based on the choice of two tee shirt options, eco-friendly tee shirts and regular cotton tee shirts. The survey was given to all customers purchasing these tee shirts in order to determine specific demographic information as well as their personal opinions on eco-friendliness, and willingness to pay a premium for eco-friendly products. Due to a lack of previous research in this field, this study is …


Measurement System For High Pressure Characterizations Of Materials, Matthew K. Jacobsen Dec 2010

Measurement System For High Pressure Characterizations Of Materials, Matthew K. Jacobsen

UNLV Theses, Dissertations, Professional Papers, and Capstones

Thermoelectric materials have long been investigated for possible use as power sources. This application was recently put to use in the Voyager space program, powering the deep space probes. Despite the usefulness of these materials, the use of pressure to investigate the material properties has only recently become interesting. As such, the work in this document was to developing a system for concurrently measuring the necessary properties. This system is capable of measuring the electrical resistivity, thermal conductivity, and Seebeck coefficient in the pressure range from 0 - 10 GPa. The results for zinc, almandine garnet, and nickel are presented …


Structures On A K3 Surface, Nathan P. Rowe Dec 2010

Structures On A K3 Surface, Nathan P. Rowe

UNLV Theses, Dissertations, Professional Papers, and Capstones

In the first part of this paper, we examine properties of K3 surfaces of the form:

(x2 + 1)(y2 + 1)(z2 + 1) + Axyz − 2 = 0


We show the surface has Picard number q " 12 by finding 12 curves whose equivalence classes are linearly independent. These curves have self intersection −2. We find the lattice representations of the single-coordinate swapping automorphisms in x, y, and z. We show that we have enough of the Lattice to make accurate predictions of polynomial degree growth under the automorphisms. We describe these automorphisms in terms of operations on elliptic …


Age And Petrogenesis Of The Roaring Mountain Rhyolites, Yellowstone Volcanic Field, Wyoming, Kathleen Marie Wooton Dec 2010

Age And Petrogenesis Of The Roaring Mountain Rhyolites, Yellowstone Volcanic Field, Wyoming, Kathleen Marie Wooton

UNLV Theses, Dissertations, Professional Papers, and Capstones

Extracaldera rhyolites in the Norris-Mammoth Corridor of the Yellowstone Volcanic Field (YVF) appear to be unrelated to intracaldera volcanism, resulting instead from a new crustal magma source derived from northeastward propagation of the Yellowstone “melting anomaly.” The youngest extracaldera rhyolite unit, the Roaring Mountain Member (RM), is chemically distinct from the previous extracaldera lavas, reverting to more primitive compositions.

This study suggests that the majority of the RM rhyolites erupted from the same large-scale silicic magma system. Based on geochemistry and 40Ar/39Ar geochronology, the Crystal Spring mingled rhyolite and Obsidian Cliff rhyolite erupted concurrently at 59.1 ± 2.0 ka. The …


Design Standards Within Constructed Wetlands For The Reduction Of Mosquito Populations In Clark County, Nevada, Phillip C. Bondurant Dec 2010

Design Standards Within Constructed Wetlands For The Reduction Of Mosquito Populations In Clark County, Nevada, Phillip C. Bondurant

UNLV Theses, Dissertations, Professional Papers, and Capstones

Wetlands are considered one of the most productive ecosystems in the world and provide many benefits to the environment. However, the slow moving and sometimes stagnant water created by the vegetation in the wetland creates an ideal environment for the proliferation of mosquitoes. Mosquitoes are the most important insect disease vector worldwide. The presence of mosquitoes within wetlands increases the risk of disease transmission among workers and visitors creating a public health concern. Effective design standards aimed at reducing mosquito breeding habitat should be implemented during the construction and planning phase of wetland development to effectively reduce the mosquito populations. …


Pattern Extraction From The World Wide Web, Praveena Mettu Dec 2010

Pattern Extraction From The World Wide Web, Praveena Mettu

UNLV Theses, Dissertations, Professional Papers, and Capstones

The World Wide Web is a source of huge amount of unlabeled information spread across different sources in varied formats. This presents us with both opportunities and challenges in leveraging such large amount of unstructured data to build knowledge bases and to extract relevant information.

As part of this thesis, a semi-supervised logistic regression model called “Dual Iterative Pattern Relation Extraction” proposed by Sergey Brin is selected for further investigation. DIPRE presents a technique which exploits the duality between sets of patterns and relations to grow the target relation starting from a small sample.

This project built in JAVA using …


Dynamic Indexing, Viswada Sripathi Dec 2010

Dynamic Indexing, Viswada Sripathi

UNLV Theses, Dissertations, Professional Papers, and Capstones

In this thesis, we report on index constructions for large document collections to facilitate the task of search and retrieval. We first report on classical static index construction methods and their shortcomings. We then report on dynamic index construction techniques and their effectiveness.


Self-Stabilizing Group Membership Protocol, Mahesh Subedi Dec 2010

Self-Stabilizing Group Membership Protocol, Mahesh Subedi

UNLV Theses, Dissertations, Professional Papers, and Capstones

In this thesis, we consider the problem of partitioning a network into groups of bounded diameter.

Given a network of processes X and a constant D, the group partition problem is the problem of finding a D-partition of X, that is, a partition of X into disjoint connected subgraphs, which we call groups, each of diameter no greater than D. The minimal group partition problem is to find a D-partition {G1, ... Gm} of X such that no two groups can be combined; that is, for any Gi and Gj, where i ≠ j, either Gi U Gj is disconnected …


Speciation And Spectroscopy Of The Uranyl And Tetravalent Plutonium Nitrate Systems: Fundamental Studies And Applications To Used Fuel Reprocessing, Nicholas A. Smith Dec 2010

Speciation And Spectroscopy Of The Uranyl And Tetravalent Plutonium Nitrate Systems: Fundamental Studies And Applications To Used Fuel Reprocessing, Nicholas A. Smith

UNLV Theses, Dissertations, Professional Papers, and Capstones

This dissertation explores the use of UV-Visible spectroscopy and Time Resolved Laser Induced Fluorescence spectroscopy as near real time process monitors of uranium and plutonium concentrations in aqueous reprocessing trains. The molar absorptivities and linear ranges of these metals were investigated under total nitrate and acid concentrations similar to those found in current reprocessing systems. Concurrent to this, a new multiple wavelength monitor was derived that is capable of determining the total nitrate concentration spectroscopically. This method uses the uranium absorbance spectrum to calculate the nitrate concentration in solution. When used as part of an Advanced Safeguard suite, this technique …


Characterization Of Unsaturated Flow In Dual-Porosity Granular Media, Jeevan A. Jayakodilage Dec 2010

Characterization Of Unsaturated Flow In Dual-Porosity Granular Media, Jeevan A. Jayakodilage

UNLV Theses, Dissertations, Professional Papers, and Capstones

A geological medium made up of uncemented coarse porous rock fragments may be described as a “dual-porosity granular medium” due to the presence of two types of pores; small pores within individual fragments and large pores between the fragments. Crushed stone found in heap leach piles, mine waste, backfills, rock drains, and engineered capillary barrier systems fit this description. Unsaturated flow in a dualporosity granular medium will occur both through the fragments (matrix flow), and on the fragment surfaces (film flow). The relative influence of gravity and capillary forces on these two flow regimes will be largely different. Therefore, unsaturated …


Late Paleozoic Deformation In The Osgood Mountains And Dry Hills, Northern Nevada, Samuel A. Siebenaler Dec 2010

Late Paleozoic Deformation In The Osgood Mountains And Dry Hills, Northern Nevada, Samuel A. Siebenaler

UNLV Theses, Dissertations, Professional Papers, and Capstones

Pennsylvanian (IP) and Permian (P) deposits (Etchart Formation) and structures in the northern Osgood Mountains and Dry Hills are identified and interpreted to reconstruct a late Paleozoic tectonic history for the time between the Antler and Sonoma orogenies. Mapping, field observations, fusulinid-based unit ages, and structural analysis are used to identify three fold and fault sets, a fault set, a fold set, and at least two angular unconformities. The faults consist of N to S striking normal faults (fault set 1) that are cross cut by WSW-ENE striking thrust faults (fault set 2). Fault sets 1 and 2 are cross …


Effect Of Spatial And Temporal Variability Of Antecedent Moisture Content On Model-Generated Runoff From An Arid Watershed, William J. Meyer Dec 2010

Effect Of Spatial And Temporal Variability Of Antecedent Moisture Content On Model-Generated Runoff From An Arid Watershed, William J. Meyer

UNLV Theses, Dissertations, Professional Papers, and Capstones

Streams in the arid southwest are typically ephemeral, and stream gages are not commonly available. Consequently, runoff data from storm events is not available, and flood control facility design or other water resource related decisions are based on synthetic hydrographs. In the Mojave Desert region of Southern Nevada, the duration of storm used to develop these synthetic hydrographs is the 6 hour storm. The 6 hour storm is used to simulate high intensity summer storms. Additionally, soils information used in the calculations for these synthetic hydrographs is taken from maps that are generally developed for a broad range of issues …


Poisson Process Monitoring, Test And Comparison, Qing Chen Dec 2010

Poisson Process Monitoring, Test And Comparison, Qing Chen

UNLV Theses, Dissertations, Professional Papers, and Capstones

The task of determining whether a sudden change occurred in the generative parameters of a time series generates application in many areas. In this thesis, we aim at monitoring the change-point of a Poisson process by method, which is characterized by a forward-backward testing algorithm and several overall error control mechanisms. With the application of this proposed method, we declare that Mount Etna is not a simple Poissonian volcano, because two different regimes divided by the change point, January 30th 1974, are identified. The validation procedures, used in a complementary fashion, by the formal hypothesis tests and graphical method will …


Sequence And Chemostratigraphy Of The Middle Cambrian Succession In Nevada And Utah, Robyn A. Howley Dec 2010

Sequence And Chemostratigraphy Of The Middle Cambrian Succession In Nevada And Utah, Robyn A. Howley

UNLV Theses, Dissertations, Professional Papers, and Capstones

The House Range Embayment of western Utah and eastern Nevada was a prominent topographic feature on the passive margin of western North America during the middle and late Cambrian. In this study, detailed documentation of sequence boundaries, and their intervening sequences across a platform-to-basin transect of the House Range Embayment was used to establish a sequence-stratigraphic framework from which the depositional history of the embayment was deciphered. This framework was then used to test the hypothesis that the House Range Embayment formed by tectonic subsidence. In addition, the chemostratigraphic (δ13Ccarb) record across the embayment was analyzed within this framework to …


Chemical And Electronic Structure Of Surfaces And Interfaces In Compound Semiconductors, Sujitra Pookpanratana Dec 2010

Chemical And Electronic Structure Of Surfaces And Interfaces In Compound Semiconductors, Sujitra Pookpanratana

UNLV Theses, Dissertations, Professional Papers, and Capstones

The interface formation between two different materials is important in applications for optoelectronic devices. Often, the success or performance of these devices is dependent on the formation of these heterojunctions. In this work, the surface and interfaces in such materials for optoelectronic devices are investigated by a suite of X-ray analytical techniques including X-ray photoelectron (XPS), X-ray excited Auger electron (XAES), and X-ray emission (XES) spectroscopies to provide novel insight.

For the group III-nitrides (e.g., AlxGa1-xN) used in many light emitting devices, a significant challenge exists to form an Ohmic contact. The electron affinities and band gaps of GaN and …


Rademacher-Type Formulas For Restricted Partition And Overpartition Functions, Andrew Sills Dec 2010

Rademacher-Type Formulas For Restricted Partition And Overpartition Functions, Andrew Sills

Mathematical Sciences: Faculty Publications

A collection of Hardy-Ramanujan-Rademacher type formulas for restricted partition and overpartition functions is presented, framed by several biographical anecdotes.


Multi-Species On-Road Remote Sensing Of Vehicle Emissions In Van Nuys, California – August 2010, Gary A. Bishop, Brent G. Schuchmann, Donald H. Stedman Dec 2010

Multi-Species On-Road Remote Sensing Of Vehicle Emissions In Van Nuys, California – August 2010, Gary A. Bishop, Brent G. Schuchmann, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

No abstract provided.


Momentum-Space Engineering Of Gaseous Bose-Einstein Condensates, Mark Edwards, Brandon Benton, Jeffrey Heward, Charles W. Clark Dec 2010

Momentum-Space Engineering Of Gaseous Bose-Einstein Condensates, Mark Edwards, Brandon Benton, Jeffrey Heward, Charles W. Clark

Physics & Astronomy: Faculty Publications

We show how the momentum distribution of gaseous Bose-Einstein condensates can be shaped by applying a sequence of standing-wave laser pulses. We present a theory, whose validity was demonstrated in an earlier experiment [L. Denget al., Phys. Rev. Lett. 83, 5407 (1999)], of the effect of a two-pulse sequence on the condensate wavefunction in momentum space. We generalize the previous result to the case of N pulses of arbitrary intensity separated by arbitrary intervals and show how these parameters can be engineered to produce a desired final momentum distribution. We find that several momentum distributions, important in …