Physical Sciences and Mathematics Commons^™

Soliton Solutions Of The Nonlinear Schrödinger Equation., Erin Middlemas

Undergraduate Honors Theses

The nonlinear Schrödinger equation is a classical field equation that describes weakly nonlinear wave-packets in one-dimensional physical systems. It is in a class of nonlinear partial differential equations that pertain to several physical and biological systems. In this project we apply a pseudo-spectral solution-estimation method to a modified version of the nonlinear Schrödinger equation as a means of searching for solutions that are solitons, where a soliton is a self-reinforcing solitary wave that maintains its shape over time. The pseudo-spectral method estimates solutions by utilizing the Fourier transform to evaluate the spatial derivative within the nonlinear Schrödinger equation. An ode …

Designing Mobile Applications Around Load-Balancing Principles To Improve Performance., Chris Eaton

Undergraduate Honors Theses

Developers of mobile applications commonly delegate computations to networked resources, which have considerably more processing capacity than contemporary mobile devices. The work described here investigates an alternative approach to managing these computations, which uses a dynamic load-balancing algorithm to divide processing work between a mobile device and a back-end server.

Web 2.0 Technologies In The Software Development Process., Jocelyn Borgers

Undergraduate Honors Theses

Software engineers must communicate with many different people, likely in different locations, in order to create a successful piece of software. Social media can be used to communicate quickly and efficiently to minimize miscommunications and facilitate collaboration in the software development process. Research in this area has been sparse but significant because initial findings show that social media is being used in innovative ways to improve software development. Surveys of what social media some companies are currently using along with information about new social media systems indicate possible uses for these technologies on future software development projects such as documentation …

Effects Of Curved Lines On Force-Directed Graphs., Marshall Couch

Undergraduate Honors Theses

The most common methods for simplifying force-directed graphs are edge-bundling and edge routing. Both of these methods can be done with curved, rather than straight, lines which some researchers have argued. Curved lines have been offered as a solution for clarifying edge resolution. Curved lines were originally thought to be more aesthetically pleasing. 32 computer science students were surveyed and asked questions about straight and curved line graphs. Research conducted by Xu et al. and this study suggests that curved lines make a graph more difficult to understand and slower to read. Research also suggests that curved lines are no …

Tweet4act: Using Incident-Specific Profiles For Classifying Crisis-Related Messages, Soudip Roy Chowdhury, Muhammad Imran, Muhammad Rizwan Asghar, Sihem Amer-Yahia, Carlos Castillo

Muhammad Imran

We present Tweet4act, a system to detect and classify crisis-related messages communicated over a microblogging platform. Our system relies on extracting content features from each message. These features and the use of an incident-specific dictionary allow us to determine the period type of an incident that each message belongs to. The period types are: pre-incident (messages talking about prevention, mitigation, and preparedness), during-incident (messages sent while the incident is taking place), and post-incident (messages related to the response, recovery, and reconstruction). We show that our detection method can effectively identify incident-related messages with high precision and recall, and that our …

Etd Conversion Utility, Logan E. Jewett

Logan E. Jewett

This presentation describes the development and operation of an ETD Conversion Utility created to prepare electronic theses and dissertations (ETD) received from ProQuest for deposit in Iowa State University's Digital Commons-based institutional repository.

N→Π* Interactions Of Amides And Thioamides: Implications For Protein Stability, Robert W. Newberry, Brett Vanveller, Ilia A. Guzei, Ronald T. Raines

Brett VanVeller

Carbonyl–carbonyl interactions between adjacent backbone amides have been implicated in the conformational stability of proteins. By combining experimental and computational approaches, we show that relevant amidic carbonyl groups associate through an n→π* donor–acceptor interaction with an energy of at least 0.27 kcal/mol. The n→π* interaction between two thioamides is 3-fold stronger than between two oxoamides due to increased overlap and reduced energy difference between the donor and acceptor orbitals. This result suggests that backbone thioamide incorporation could stabilize protein structures. Finally, we demonstrate that intimate carbonyl interactions are described more completely as donor–acceptor orbital interactions rather than dipole–dipole interactions.

Using Partial Differential Equations To Model And Analyze The Treatment Of A Chronic Wound With Oxygen Therapy Techniques, Brandon C. Russell

Mahurin Honors College Capstone Experience/Thesis Projects

Chronic wounds plague approximately 1.3-3 million Americans. The treatment of these wounds requires knowledge of the complex healing process of typical wounds. With a system of partial differential equations, this project attempts to model the intricate biological process and to describe oxygen levels, neutrophil and bacteria concentrations, and other biological parameters with respect to time and space. Analytical solutions for the model will be derived for various frames of time in the wound-healing process. The system of equations will be numerically solved using Matlab. Numerical simulations are performed to determine optimal treatment strategies for a chronic wound.

Electron Transport In Quantum Dot Chains: Dimensionality Effects And Hopping Conductance, V. P. Kunets, Mariama Rebello Sousa Dias, T. Rembert, M. E. Ware, Y. I. Mazur, V. Lopez-Richard, H. A. Mantooth, G. E. Marques, G. J. Salamo

Physics Faculty Publications

Detailed experimental and theoretical studies of lateral electron transport in a system of quantum dot chains demonstrate the complicated character of the conductance within the chain structure due to the interaction of conduction channels with different dimensionalities. The one-dimensional character of states in the wetting layer results in an anisotropic mobility, while the presence of the zero-dimensional states of the quantum dots leads to enhanced hopping conductance, which affects the low-temperature mobility and demonstrates an anisotropy in the conductance. These phenomena were probed by considering a one-dimensional model of hopping along with band filling effects. Differences between the model and …

Planet Hunters: A Transiting Circumbinary Planet In A Quadruple Star System, Megan E. Schwamb, William C. Keel

Aerospace, Physics, and Space Science Faculty Publications

We report the discovery and confirmation of a transiting circumbinary planet (PH1b) around KIC 4862625, an eclipsing binary in the Kepler field. The planet was discovered by volunteers searching the first six Quarters of publicly available Kepler data as part of the Planet Hunters citizen science project. Transits of the planet across the larger and brighter of the eclipsing stars are detectable by visual inspection every ∼137 days, with seven transits identified in Quarters 1–11. The physical and orbital parameters of both the host stars and planet were obtained via a photometric-dynamical model, simultaneously fitting both the measured radial velocities …

An Examination Of Presentation Strategies For Textual Data In Augmented Reality, Kanrawi Kitkhachonkunlaphat

Department of Computer Graphics Technology Degree Theses

Videos with embedded text have been widely used in the past and the text in the videos usually contained valuable information. However, it was difficult for people to fully understand the text in videos displayed on smartphones due to obstructions such as color conflicts between letters and the moving background. Adjustments to texts that would support the human visual system, such as changes to brightness and color contrast, increased legibility of text, and taking into account the phantom illumination (PI) illusion (the optical illusion that increases the perception of brightness in a certain area), should be able to improve peoples’ …

A New Class Of Gold Nanoantibotics - Direct Coating Of Ampicillin On Gold Nanoparticles, Dillon S. Pender

Mahurin Honors College Capstone Experience/Thesis Projects

Need for novel, innovative strategies for developing antibiotics is becoming a necessity due to an increasing number of rapidly evolving micro-organismal threats. Antibiotic encapsulated gold nanoparticles (GNPs) are one such strategy showing promise. We report the development of ampicillin encapsulated gold nanoparticles (Amp-GNPs) that possess highly effective, dose dependant antibacterial activity. In this method, ampicillin molecules have been coated on individual GNPs which can then serve as drug carrier devices. Our method for synthesizing Amp-GNPs is an entirely ecofriendly, single step reaction taking place in an aqueous buffer. Following characterization of Amp-GNPs, we find them to be ~15 nm in …

Differential Hydrogen Bonding In Human Cyp17 Dictates Hydroxylation Versus Lyase Chemistry, Michael Gregory, Piotr J. Mak, Stephen G. Sligar, James R. Kincaid

Chemistry Faculty Research and Publications

Consequences of alternative H-bonding: Raman spectra of oxygenated intermediates of Nanodisc-incorporated human CYP17 in the presence of natural substrates (pregnenolone and progesterone) directly confirm that substrate structure effectively alters hydrogen-bonding interactions with the critical Fe–O–O fragment and dictates its predisposition for one of two alternative reaction pathways. Such substrate control has profound physiological implications.

Exploring Freshmen College Students' Self-Efficacy, Attitudes, And Intentions Toward Chemistry, Amanda F. Cook

Mahurin Honors College Capstone Experience/Thesis Projects

This study examined the self-efficacy beliefs, attitudes towards general chemistry, and intentions to take future chemistry courses in a sample of (n = 1,126) first-time, first-year freshmen from a large comprehensive university in the Mid-South. The main purpose of the study was to determine the amount of variance in students’ intentions which could be predicted by self-efficacy, attitudes, and other known influences (past performance, past experience and choice of major). Findings from a standard multiple regression indicate that self-efficacy (β = 0.07, p < .05) and attitude (β = 0.50, p < .001) are both significant and predict 29.3% of the variance in intentions, with attitudes making a larger unique contribution. Using a hierarchical regression to control for other known factors, self-efficacy and attitudes were still able to predict 23.5% of the variance in intentions. Overall, the five independent variables were able to predict 31.7% of the variance in intentions. Implications for secondary and postsecondary science educators and STEM administrators are discussed.

Complex Network Growing Model Using Downlink Motifs, Ahmad Al-Musawi Jr.

Theses and Dissertations

Understanding the underlying architecture of gene regulatory networks (GRNs) has been one of the major goals in systems biology and bioinformatics as it can provide insights in disease dynamics and drug development. Such GRNs are characterized by their scale-free degree distributions and existence of network motifs, which are small subgraphs of specific types and appear more abundantly in GRNs than in other randomized networks. In fact, such motifs are considered to be the building blocks of GRNs (and other complex networks) and they help achieve the underlying robustness demonstrated by most biological networks. The goal of this thesis is to …

Host Star Properties And Transit Exclusion For The Hd 38529 Planetary System, G. W. Henry, S. R. Kane, S. X. Wang, T. S. Boyajian, K. Von Braun, D. R. Ciardi, D. Dragomir, C. Farrington, D. A. Fischer, N. R. Hinkel, A. W. Howard, Eric L.N. Jensen, G. Laughlin, S. Mahadevan, G. Pilyavsky

Physics & Astronomy Faculty Works

The transit signature of exoplanets provides an avenue through which characterization of exoplanetary properties may be undertaken, such as studies of mean density, structure, and atmospheric composition. The Transit Ephemeris Refinement and Monitoring Survey is a program to expand the catalog of transiting planets around bright host stars by refining the orbits of known planets discovered with the radial velocity technique. Here we present results for the HD 38529 system. We determine fundamental properties of the host star through direct interferometric measurements of the radius and through spectroscopic analysis. We provide new radial velocity measurements that are used to improve …

The Fierce Green Fire: Vol. 3 Issue 25, Wofford College Environmental Studies Program

The Fierce Green Fire

No abstract provided.

The Santa Clara, 2013-05-09, Santa Clara University

The Santa Clara

No abstract provided.

The Contribution Of Fe (Iii) And Humic Acid Reduction To Ecosystem Respiration In Drained Thaw Lake Basins Of The Arctic Coastal Plain, David A. Lipson, Ted K. Raab, Dominic Goria, Jaime Zlamal

Ted K. Raab

Previous research showed that anaerobic respiration using iron (Fe) oxides as terminal electron acceptor contributed substantially to ecosystem respiration (ER) in a drained thaw lake basin (DTLB) on the Arctic coastal plain. As DTLB age, the surface organic layer thickens, progressively burying the Fe-rich mineral layers. We therefore hypothesized that Fe (III) availability and Fe reduction would decline with basin age. We studied four DTLB across an age gradient, comparing seasonal changes in the oxidation state of dissolved and extractable Fe pools and the estimated contribution of Fe reduction to ER. The organic layer thickness did not strictly increase with …

Systematic Study Of (P,Γ) Reactions On Ni Isotopes, A. Simon, A. Spyrou, T. Rauscher, C. Froehlich, S. J. Quinn, A. Battaglia, A. Best, B. Bucher, M Couder, Paul A. Deyoung, X. Fang, J. Goerres, A. Kontos, Q. Li, L. Y. Lin, A. Long, S. Lyons, A. Roberts, D. Robertson, K. Smith, M. K. Smith, E. Stech, B. Stefanek, W. P. Tan, X. D. Tang, M. Wiescher

Faculty Publications

AA systematic study of the radiative proton capture reaction for all stable nickel isotopes is presented. The results were obtained using 2.0–6.0 MeV protons from the 11-MV tandem Van de Graaff accelerator at the University of Notre Dame. The γ rays were detected by the NSCL-SuN detector utilizing the γ-summing technique. The results are compared to a compilation of earlier measurements and discrepancies between the previous data are resolved. The experimental results are also compared to the theoretical predictions obtained using the non-smoker and smaragd codes. Based on these comparisons an improved set of astrophysical reaction rates is proposed for …

College Of Engineering Senior Design Competition Spring 2013, University Of Nevada, Las Vegas

Fred and Harriet Cox Senior Design Competition Projects

Senior Design Experience

Part of every UNLV engineering student's academic experience, the Senior Design project stimulates engineering innovation and entrepreneurship. Each student in their senior year chooses, plans, designs and prototypes a product in this required element of the curriculum. Working in teams, the senior design project encourages students to use everything learned in the engineering and computer design programs to create a practical, real world solution to an engineering challenge.

Beyond the classroom ...

Because of the requirement to work in teams, students also build good communication skills, presentation skills and even business writing skills. They also have to …

Increasing Ca2+ Deposition In The Western Us: The Role Of Mineral Aerosols, Janice Brahney, Ashley P. Ballantyne, C. Sievers, Jason C. Neff

Watershed Sciences Faculty Publications

Considerable research has focused on the role of industrial emissions in controlling the acidity of precipitation; however, much less research has focused on the role of mineral aerosols emitted from soils. According to data published by the National Atmospheric Deposition Network (NADP), over the past 17 years Ca2+ deposition has increased over large regions of the US. A trend analysis to determine regions of significant change in Ca2+ deposition revealed statistically significant increases in three broad regions within the western half of the country: the inter-mountain west, the midwest, and the northwest. We evaluated potential changes in sources of calcium …

Extending Technology Roadmap Through Fuzzy Cognitive Map-Based Scenarios: The Case Of The Wind Energy Sector Of Pakistan, Muhammad Amer

Dissertations and Theses

In this modern era, energy is a key element required for sustainable development and prosperity of a society. Pakistan is an energy deficient country facing problems due to the shortage of over 4000 MW of electricity. The national energy sector is heavily dependent on imported fossil-fuel resources. The energy crisis is negatively affecting all economic and business activities, and it is widely recognized as a severe obstacle to growth and poverty reduction in the country. Establishment of wind farms can help to overcome the energy crisis.

In this research, a national level wind energy roadmap is developed through scenario planning. …

Representing Game Dialogue As Expressions In First-Order Logic, Kaylen Fj Wheeler

Electronic Thesis and Dissertation Repository

Despite advancements in graphics, physics, and artificial intelligence, modern video games are still lacking in believable dialogue generation. The more complex and interactive stories in modern games may allow the player to experience different paths in dialogue trees, but such trees are still required to be manually created by authors. Recently, there has been research on methods of creating emergent believable behaviour, but these are lacking true dialogue construction capabilities. Because the mapping of natural language to meaningful computational representations (logical forms) is a difficult problem, an important first step may be to develop a means of representing in-game dialogue …

Cluster Expansion Models Via Bayesian Compressive Sensing, Lance Jacob Nelson

Theses and Dissertations

The steady march of new technology depends crucially on our ability to discover and design new, advanced materials. Partially due to increases in computing power, computational methods are now having an increased role in this discovery process. Advances in this area speed the discovery and development of advanced materials by guiding experimental work down fruitful paths. Density functional theory (DFT)has proven to be a highly accurate tool for computing material properties. However, due to its computational cost and complexity, DFT is unsuited to performing exhaustive searches over many candidate materials or for extracting thermodynamic information. To perform these types of …

Energy Independence In The Usa, Janice Ringler

Student Papers in Public Policy

During President Barack Obama’s first term and throughout the recent presidential campaign, there was much discussion about becoming energy-independent as a nation. Indeed, one of the most pressing issues facing the country today is our energy future. This is especially a concern in areas where mainstream energy sources (coal, gas, oil) do not exist, and thus must be imported. Many believe that this is a problem that communities and states are better suited to tackle than the federal government due to the flexibility and knowledge of state policy initiatives. In this brief I will propose a variety of measures that …

Differential Effects Of Membrane Order On Membrane Permeability, Miranda J. Bradley, Marshall J. Colville, Miles J. Crumley, Drake C. Mitchell

Student Research Symposium

Phospholipid membranes segregate into lateral domains of liquid ordered (lo) and liquid disordered (ld) phases when cholesterol and mixed species of lipids with saturated and unsaturated acyl chains are present. To examine membrane permeability and rate of vesicle rupture by Triton in pure lo, pure ld, and mixed lo/ld phases, LUVs were prepared based on the ternary phase diagram of POPC, sphingomyelin, and cholesterol. These LUVs were loaded with 2mM carboxyfluorescein (CF) and formed by extrusion at 65oC. Using a stopped-flow fluorometer, changes in CF fluorescence were measured when LUVs were exposed to sudden osmotic gradients, pH gradients, or 0.1% …

Training An Asymmetric Signal Perceptron In An Artificial Chemistry, Peter Banda

Student Research Symposium

Autonomous learning implemented purely by means of a synthetic chemical system has not been previously realized. Learning promotes reusability, and minimizes the system design to simple input-output specification. In this poster, I present a simulated chemical system, the first full-featured implementation of a perceptron in an artificial (simulated) chemistry, which can successfully learn all 14 linearly separable logic functions. A perceptron is the simplest system capable of learning inspired by the functioning of a biological neuron. My newest model called the asymmetric signal perceptron (ASP) is, as opposed to its predecessors such as the weight-race perceptron (WRP), substantially simpler by …

An Alternative Ribozyme For The Rna Hypercycle, Ishak Elkhal

Student Research Symposium

In the quest to forward understanding of the prebiotic world (specifically, the RNA World Hypothesis), one of the most interesting paradigms to consider is the potential for cooperative networks that may have driven molecular evolution forward. Such a network may exist as an RNA hypercycle, as proposed by Eigen (1977). Much progress has been made towards an RNA hypercycle-like system, especially using the Azoarcus ribozyme system demonstrated by Vaidya et al. (2012). The current work is dedicated to constructing a second model as a cooperative RNA network, utilizing a group I intron from Coxiella burnetii (Cbu1917). The intron was constructed …

Multiband S -Wave Topological Superconductors: Role Of Dimensionality And Magnetic Field Response, Shusa Deng, Gerardo Ortiz, Lorenza Viola

Dartmouth Scholarship

We further investigate a class of time-reversal-invariant two-band s-wave topological superconductors introduced earlier [Deng, Viola, and Ortiz, Phys. Rev. Lett. 108, 036803 (2012)]. Provided that a sign reversal between the two superconducting pairing gaps is realized, the topological phase diagram can be determined exactly (within mean field) in one and two dimensions as well as in three dimensions upon restricting to the excitation spectrum of time-reversal-invariant momentum modes. We show how, in the presence of time-reversal symmetry, Z2 invariants that distinguish between trivial and nontrivial quantum phases can be constructed by considering only one of the Kramers’ sectors …