Physical Sciences and Mathematics Commons^™

Biomineralization Of Carbonates In Modern Microbial Sediments And Its Implications For Co₂ Sequestration, Varun Gnanaprian Paul

Doctoral Dissertations

"Several bacterial species influence carbonate mineral precipitation by modifying pH, alkalinity, Ca²⁺ activity and by providing nucleation sites for mineralization. Two studies have been undertaken to explore microbial influence in the mineralization of carbonates. In the first study, the ability of sulfate-reducing bacteria (SRB) to induce carbonate mineralization was investigated as a means to enhance mineral sequestration of CO₂. Sulfate-reducing bacteria enriched from hypersaline Storr's Lake, The Bahamas; Lake Estancia, New Mexico; and Great Salt Plains Lake, Oklahoma, were tested in reactors under varying CO₂ concentrations. Carbonate mineral precipitation was achieved only in reactors with Lake Estancia SRB community and …

Graphite Aerogels And The Formation Mechanism Of Unusual Micron-Sized Rod And Helical Structures, Clarissa Ann Wisner

Doctoral Dissertations

"Pyrolysis at 800 ºC under argon has shown that polyimide (PI), polyacrylonitrile (PAN), polydicyclopentadiene (DCPD) and polybenzoxazine (PBO) aerogels are all viable alternatives to traditional resorcinol-formaldehyde (RF) aerogels as precursors to amorphous carbon aerogels. Subsequent high temperature pyrolysis at 2300 ºC of such carbon aerogels under helium has shown that amorphous carbon from PI and PBO yields the highest degree of graphitization, whereas from RF aerogels yields the lowest.

Those two types of graphite aerogels include also a high concentration of micron-size columnar and helical (screw-like) structures, whose formation is favored by macroporosity and high nitrogen retention in the 800 …

Seismic Anisotropy And Mantle Flow Beneath Africa And Arabia, Ahmed Abdalla Elsheikh

Doctoral Dissertations

"In spite of numerous studies, the mechanisms for the rifting, uplifting, and volcanism on the African plate remain enigmatic. The most popular hypotheses proposed for explaining these tectonic phenomena involve edge-driven small-scale mantle convection and the thermal or dynamic effects of one or more mantle plumes. In this study we use continental scale shear-wave splitting (SWS) measurements to provide additional constraints on the various models of rifting, uplifting, and volcanism of the Cameroon Volcanic Line (CVL) and the Arabian plate. The splitting of P-to-S converted phases at the core-mantle boundary on the receiver side (XKS including PKS, SKKS, and SKS) …

3d Image Acquisition System For Facial Recognition, James E. Pearson

EWU Masters Thesis Collection

Identification of an individual has been a long standing problem in human existence. It is clear from the rising rates of identity theft and misappropriation of services that current methods employed to identify individuals is ineffectual. The most common way people identify other individuals is via recognition of the subjects face. The speed and accuracy with which one person can identify another person is uncanny leading to the development automated facial recognition systems. The vast majority of these systems use two-dimensional (2D) images imagery to perform facial recognition with limited success. The use of 2D imagery has limitations which cannot …

Divide And Conquer G-Buffer Ray Tracing, Daniel Stokes

EWU Masters Thesis Collection

No abstract provided.

Iowa Waste Reduction Center Newsletter, January 2014, University Of Northern Iowa. Iowa Waste Reduction Center.

Iowa Waste Reduction Center Newsletter

Inside this Issue:

--- A Note from the Director
--- 2014/2015 Calendars
--- Iowa News
--- National News

Factors That Contribute To The Establishment Of Marine Protected Areas In Western Australia, Andrew Hill

Theses

Five Marine Protected Area (MPA) establishment processes undertaken between 1998 and 2012 in Western Australia were reviewed using a case study approach to identify factors affecting establishment. While three MPAs were legally created, two were not, despite significant investment in planning, research and public participation. Processes were generally influenced by complex local and strategic planning issues that were significant barriers to legal establishment.

Planning and public participation processes were generally successful at addressing local concerns, deriving consensus and building ownership but ineffectual at addressing key strategic issues. MPA establishment was primarily influenced by the social, economic and political influences rather …

Coupling Graphs, Efficient Algorithms And B-Cell Epitope Prediction, Liang Zhao, Steven C. H. Hoi, Zhenhua Li, Limsoon Wong, Hung Nguyen

Research Collection School Of Computing and Information Systems

Coupling graphs are newly introduced in this paper to meet many application needs particularly in the field of bioinformatics. A coupling graph is a two-layer graph complex, in which each node from one layer of the graph complex has at least one connection with the nodes in the other layer, and vice versa. The coupling graph model is sufficiently powerful to capture strong and inherent associations between subgraph pairs in complicated applications. The focus of this paper is on mining algorithms of frequent coupling subgraphs and bioinformatics application. Although existing frequent subgraph mining algorithms are competent to identify frequent subgraphs …

Stability Of Traveling-Wave Solutions For A Schrodinger System With Power-Type Nonlinearities, Nghiem Nguyen, Rushun Tian, Zhi-Qiang Wang

Mathematics and Statistics Faculty Publications

In this article, we consider the Schrodinger system with powertype nonlinearities, (Formula presented) where j = 1,...,m, u_j are complex-valued functions of (x, t) 2 R^N+1, a, b are real numbers. It is shown that when b > 0, and a + (m - 1)b > 0, for a certain range of p, traveling-wave solutions of this system exist, and are orbitally stable.

A Shortcut For Multiple Testing On The Directed Acyclic Graph Of Gene Ontology, Garrett Saunders, John R. Stevens, S. Clay Isom

Mathematics and Statistics Faculty Publications

Background: Gene set testing has become an important analysis technique in high throughput microarray and next generation sequencing studies for uncovering patterns of differential expression of various biological processes. Often, the large number of gene sets that are tested simultaneously require some sort of multiplicity correction to account for the multiplicity effect. This work provides a substantial computational improvement to an existing familywise error rate controlling multiplicity approach (the Focus Level method) for gene set testing in high throughput microarray and next generation sequencing studies using Gene Ontology graphs, which we call the Short Focus Level.

Results: The Short Focus …

Dynamical Monodromy, C. Chen, Megan K. Ivory, Seth Aubin, John B. Delos

Arts & Sciences Articles

Integrable Hamiltonian systems are said to display nontrivial monodromy if fundamental action-angle loops defined on phase-space tori change their topological structure when the system is carried around a circuit. In an earlier paper it was shown that this topological change can occur as a result of time evolution under certain rather abstract flows in phase space. In the present paper, we show that the same topological change can occur as a result of application of ordinary forces. We also show how this dynamical phenomenon could be observed experimentally in classical or in quantum systems.

Unintended Outcomes Of Farmers' Adaptation To Climate Variability: Deforestation And Conservation In Calakmul And Maya Biosphere Reserves, Claudia Rodriguez-Solorzano

Dartmouth Scholarship

Minimizing the impact of climate change on farmer livelihoods is crucial, but adaptation efforts may have unintended consequences for ecosystems, with potential impacts on farmers’ welfare. Unintended outcomes of climate adaptation strategies have been widely discussed, however, empirical exploration has been neglected. Grounded in scholarship on climate adaptation, environmental governance, social–ecological systems, and land-use change, this paper studies whether farmers’ climate adaptation contributes to deforestation or forest conservation. The paper draws on interviews with 353 farmers from 46 communities in Calakmul Biosphere Reserve in Mexico and Maya Biosphere Reserve in Guatemala. Farmers in the area of study have implemented adaptation …

Source Characterization Of African Soils Using Computer Controlled Sem Analysis, Robert Mace Rogers

Earth & Environmental Sciences Dissertations

An investigation is underway to determine whether African dust can be chemically distinguished by regions and whether it is developed through Pedogenic or Aeolian processes. A total of 29 dust samples were taken from the Sahel and Saharan region of Africa and are to be analyzed using computer controlled scanning electron microscopy (CCSEM). CCSEM collects data on size shape and chemical composition on individual microscopic dust particles present in a media sample analyzed in a scanning electron microscope (SEM). Back-scattered electron imaging (BEI) in the SEM is accomplished using a four-quadrants backscatter electron detector. This method of imaging the particles …

Sensitivity Of The Late Permian Climate To Tectonic And Radiative Forcing Changes: Implications For The Mass Extinction, Angela Osen

Earth & Environmental Sciences Dissertations

The largest mass extinction occurred near the Permian-Triassic boundary (ca. 252 Ma). Significant carbon isotope shifts indicate that perturbations in the carbon cycle occurred during the Late Permian and persisted into the Early Triassic. The loss of biodiversity within the terrestrial and marine realms coincided with the eruption of the Siberian Flood Basalts and magma intrusion into coal beds, leading to the emission of greenhouse, sulfur, and other gases into the atmosphere. In this study, climate model output from the Community Climate System Model Version 3 with improved topographic features, along with a prediction of patterns of oceanic water masses …

From Map To Dist: The Evolution Of A Large-Scale Wlan Monitoring System, Keren Tan, Chris Mcdonald, Bennet Vance, Chrisil Arackaparambil, Sergey Bratus, David Kotz

Dartmouth Scholarship

The edge of the Internet is increasingly becoming wireless. Therefore, monitoring the wireless edge is important to understanding the security and performance aspects of the Internet experience. We have designed and implemented a large-scale WLAN monitoring system, the Distributed Internet Security Testbed (DIST), at Dartmouth College. It is equipped with distributed arrays of “sniffers” that cover 210 diverse campus locations and more than 5,000 users. In this paper, we describe our approach, designs and solutions for addressing the technical challenges that have resulted from efficiency, scalability, security, and management perspectives. We also present extensive evaluation results on a production network, …

Testing Longitudinal Data By Logarithmic Quantiles, Manfred Denker, Lucia Tabacu

Mathematics & Statistics Faculty Publications

The shoulder tip pain study of Lumley [13] is re-investigated. It is shown that the new logarithmic quantile estimation (LQE) technique in [9] applies and behaves well under singular covariance structure and small sample sizes as in the shoulder tip pain study. The findings in [6] can be assured under weaker assumptions using a combination of LQE and an ANOVA type statistic. © 2014, Institute of Mathematical Statistics.

Network-Based Assessments Of Percolation-Induced Current Distributions In Sheared Rod Macromolecular Dispersions, Feng Shi, Simi Wang, M. Gregory Forest, Peter J. Mucha, Ruhai Zhou

Mathematics & Statistics Faculty Publications

Conducting high-aspect-ratio rods with 1-10 nm-scale diameters dispersed in poorly conducting matrices at extremely low, O(1%), volume fractions induce dramatic gains in bulk conductivity at rod percolation threshold. Experimentally [Nan, Shen, and Ma, Annu. Rev. Mater. Res., 40 (2010), pp. 131-151], bulk conductivity abandons the prepercolation, linear scaling with volume fraction that follows from homogenization theory [Zheng et al., Adv. Funct. Mater., 15 (2005), pp. 627-638], and then postpercolation jumps orders of magnitude to approach that of the pure rod macromolecular phase as predicted by classical percolation theory [Stauffer and Aharony, Introduction to Percolation Theory, CRC …

Scalar Wave Scattering By Two-Layer Radial Inhomogeneities, Umaporn Nuntaplook, John Adam

Mathematics & Statistics Faculty Publications

It is shown that the iteration technique gives a better approximation for the problem with long wavelengths.

A Direct Solver With O(N) Complexity For Variable Coefficient Elliptic Pdes Discretized Via A High-Order Composite Spectral Collocation Method, A. Gillman, P. G. Martinsson

Dartmouth Scholarship

A numerical method for solving elliptic PDEs with variable coefficients on two-dimensional domains is presented. The method is based on high-order composite spectral approximations and is designed for problems with smooth solutions. The resulting system of linear equations is solved using a direct (as opposed to iterative) solver that has optimal $O(N)$ complexity for all stages of the computation when applied to problems with nonoscillatory solutions such as the Laplace and the Stokes equations. Numerical examples demonstrate that the scheme is capable of computing solutions with a relative accuracy of $10^{-10}$ or better for challenging problems such as highly oscillatory …

A Generalized Approach To Darboux Transformations For Differential Equations, Mehmet Unlu

Mathematics Dissertations

A Darboux transformation is a mathematical procedure to produce a solution to a differential equation when the solution to a related differential equation is known. The basic idea behind a Darboux transformation is to change the discrete spectrum of a linear differential operator in a controlled way without changing its continuous spectrum. For example, by using a Darboux transformation one can describe the change in a quantum mechanical system when some of its quantum levels are removed or some extra quantum levels are added. Darboux transformation formulas for various differential equations have been developed, but such formulas seem to be …

Weight Modules Of Orthosymplectic Lie Superalgebras, Thomas Lynn Ferguson

Mathematics Dissertations

A long-standing problem in representation theory is the classification of all simple weight modules of the classical Lie superalgebras. This problem was reduced to the classification of simple bounded highest weight modules. The latter classification has been accomplished for all classical Lie superalgebras except for the orthosymplectic series osp(m|2n) where m = 1, 3, 4, 5, 6. In this thesis, we complete the classification of the simple bounded highest weight modules of osp(1|2n) (i.e., for m = 1). The classification is obtained by developing constraints on primitive vectors in tensor products of bounded (Weyl) and finite-dimensional osp(1|2n)-modules.

Differential Equation Models Of Foreign Body Fibrotic Reactions For Assessing Roles Of Macrophage Phenotypes And Mesenchymal Stem Cells, Larrissa Owens

Mathematics Dissertations

Implant failure due to fibrotic encapsulation is an ongoing challenge in the bio-medical field. We develop two mathematical models based on partial differential equations in two spatial dimensions, and use them to gain quantitative insights regarding the dynamics of immune cells and proteins following the insertion of a foreign body. We focus heavily on incorporating a distinction between varied phenotypes of macrophage cells and analyzing their effects on healing processes. We extend our research to a new model that incorporates mesenchymal stem cells that influence the chemical reactions of immune regulators. Stability analysis is conducted on a family of equilibria …

A Method For Exact Solutions To Integrable Evolution Equations In 2+1 Dimensions, Alicia Machuca

Mathematics Dissertations

A systematic method is developed to obtain solution formulas for certain explicit solutions to integrable nonlinear partial differential equations in two spatial variables and one time variable. The method utilizes an underlying Marchenko integral equation that arises in the corresponding inverse scattering problem. The method is demonstrated for the Kadomtsev-Petviashvili and the generalized Davey-Stewartson II system. A derivation and analysis of the solution formulas to these two nonlinear partial differential equations are given, and an independent verification of the solution formulas is presented. Such solution formulas are expressed in a compact form in terms of matrix exponentials, by using a …

Estimation Of Variance In Bivariate Normal Distribution After Preliminary Test Of Homogeneity, Juan Manuel Romero Padilla

Mathematics Dissertations

A preliminary test estimator of variance in the bivariate normal distribution is proposed after Pitman-Morgan test of homogeneity of two variances. We propose one estimator of variance after preliminary test of two tails and another one for one tail test. The biases and mean square errors of both estimators are derived. The relative efficiency (RE) of the preliminary test estimator is studied. Computations and 3D graphs of RE for different parameters are analyzed. In order to get the maximum RE, recommendations of the significance level for the preliminary test are given for various sample sizes by using the max-min criterion.

Applications Of Cubical Arrays In The Study Of Finite Semifields, Kelly Casimir Aman

Mathematics Dissertations

It is well known that any finite semifield, S, can be viewed as an n-dimensional vector space over a finite field or prime order, Fp, and that the multiplication in S defines and can be defined by an n x n x n cubical array of scalars, A. For any element a E S, the matrix, La, corresponding to left multiplication by a can be determined from A. In this paper we show that there exists a unique monic polynomial of minimal degree, f E Fp[x], such that f(a) = 0, and which divides the minimal polynomial of La. Furthermore, …

Growth And Analysis Of Micro And Nano Cdte Arrays For Solar Cell Applications, Brandon Adrian Aguirre

Open Access Theses & Dissertations

CdTe is an excellent material for infrared detectors and photovoltaic applications. The efficiency of CdTe/CdS solar cells has increased very rapidly in the last 3 years to ~20% but is still below the maximum theoretical value of 30%. Although the short-circuit current density is close to its maximum of 30 mA/cm2, the open circuit voltage has potential to be increased further to over 1 Volt. The main limitation that prevents further increase in the open-circuit voltage and therefore efficiency is the high defect density in the CdTe absorber layer. Reducing the defect density will increase the open-circuit voltage above 1 …

Resampling-Based Multiple Comparisons For Generalized Linear Models, Josephine Sarpong Akosa

Open Access Theses & Dissertations

Diverse applications in medical and epidemiological research routinely utilize generalized linear modeling to explain the relationship between the incidence of disease and particular risk factors. Researchers' interest in such models are estimated quantities from the model such as the response probabilities, the relative risks or the odds ratios and not the model itself. Often, the simultaneous estimation of these quantities or a subset of the quantities are warranted. The results are usually reported via confidence intervals at a pre-specified level of significance. Utilizing the usual 95% pointwise confidence intervals for the simultaneous inference inflates the risk of making type I …

A New Bivariate Distribution With Applications, Sathya Amarasekara

Open Access Theses & Dissertations

We construct a bivariate distribution of (X, Y ) by assuming that the conditional distribution of Y given X is a two-parameter Gamma (s, ν(x)), where the scale parameter depends on X. If X is assumed to be any distribution, then clearly the joint distribution is well defined in all cases. We will study this new distribution by developing all possible properties, moments, shapes and estimation of parameters with a view towards applications of the distribution to data from many random number generation methods.

Simulation Of Heat And Mass Transfer In Suns River Solar Distillation, Houman Azari

Open Access Theses & Dissertations

Many regions around the world have limited fresh water resources, and we need to desalinate brackish water resources for drinking and irrigation purposes. Most of the world is also facing energy challenges which encourages engineers and scientists to use renewable energy resources instead of hydrocarbon fuels. Arid regions such as the Middle East, many African countries, and the southwestern United States typically have abundant solar irradiance and brackish or saline water supplies. Solar-thermal desalination could be an important supply of fresh water in these regions.

The classic solar still is not efficient for providing large amounts of clean water for …

A Study Of Ti-Doped Wo3 Thin Films Using Comparative Theoretical And Experimental Approach, Aurelio Paez

Open Access Theses & Dissertations

Metal oxides like Tungsten Oxide (WO3) are well documented and characterized in the literature, with uses in darkening windows and mirrors, flat computer displays, solar panel cooling, and sensors (of interest in this study). Ti doping of WO3 is less documented and the focus of this study. Sample thin films of pure WO3 and varyingly Ti doped WO3 were prepared using Radio Frequency magnetron sputtering (RF) (13.56 MHz) to grow thin films on a silicon substrate. This study aims to compare multiple Ti doping percentages in WO3 theoretically and then compare with experimental data taken from thin films of various …