Physical Sciences and Mathematics Commons^™

A Nonlinear Splitting Algorithm For Systems Of Partial Differential Equations With Self-Diffusion, Matthew Beauregard, Joshua L. Padgett, Rana D. Parshad

Faculty Publications

Systems of reaction-diffusion equations are commonly used in biological models of food chains. The populations and their complicated interactions present numerous challenges in theory and in numerical approximation. In particular, self-diffusion is a nonlinear term that models overcrowding of a particular species. The nonlinearity complicates attempts to construct efficient and accurate numerical approximations of the underlying systems of equations. In this paper, a new nonlinear splitting algorithm is designed for a partial differential equation that incorporates self diffusion. We present a general model that incorporates self-diffusion and develop a numerical approximation. The numerical analysis of the approximation provides criteria for …

"Sorbents For Carbon Dioxide Capture.", J. Brannon Gary

Faculty Publications

Provided herein are sorbents for carbon dioxide (CO₂) capture, such as from natural gas and coal-fired power plant flue gases, and uses thereof.

A Photometric Study Of The Eclipsing Binary Star Uv Lyncis, Edward J. Michaels

Bright Ideas Conference

UV Lyncis is a short period, over contact eclipsing binary star. These stars are physically in contact with each other, sharing a common atmosphere. Photometric observations were made on 10 nights in February and March 2014 using the 0.3 meter robotic telescope and a CCD science imager at the Waffelow Creek Observatory. 3051 images were acquired, calibrated and then reduced to record the changing brightness as the two stars orbited and eclipsed each other. Data collected resulted in complete light curves in 5 band passes and several times of minima. A period analysis confirmed previous studies that the orbital period …

A Fixed-Inverse Binary Misclassification Model Under Possible False-Positive Misclassification, Asmerom Tesfamichael, Kent Riggs

Bright Ideas Conference

In this project, we develop a particular statistical model for binary data that allows for the possibility of false-positive misclassification. To account for the misclassification, the model incorporates a two-stage sampling scheme.

• Next, we apply maximum likelihood methods to find estimators of the primary prevalence parameter p as well as the false-positive misclassification rate parameter ϕ. In addition, we derive confidence intervals for p based on inverting Wald, score and likelihood ratio statistics.

• Also, we graphically compare coverage and width properties of the Wald-based, score-based, and likelihood ratio-based confidence intervals for p through a Monte Carlo simulation. The …

How Visualization Can Improve The Understanding Of Mathematics, Mariah Martin

Undergraduate Research Conference

High school students have a difficult time taking the new End-Of-Course exams in math. Why are students having this difficulty? This could be because students lack the understanding of visualization in mathematics. Visualization can be helpful to certain students who think this way, while also confusing to those same students, and others as well. However, to what extent do high stakes tests, such as the End-Of-Course exams in Algebra I and II, incorporate mathematical visualization? How can visualization help improve the understanding of mathematics? This review will explain the advantages and disadvantages of incorporating visualization in these exams, how students …

Baseline Water Quality For Lanana Creek Within The Nacogdoches Area, Tania Benavides, Greg Hanson, Phillip Sharp

Undergraduate Research Conference

Lanana Creek is one of two springs that surround Nacogdoches, TX. Lanana Creek starts southwest of Lake Naconiche, conjoining with several other bodies of water along its path, and becomes part of the Angelina River. This body of water eventually ends in the Gulf of Mexico which may contribute to the dead zone. Contaminants in water may be of small concentration; however, prolonged exposure could produce many negative effects. To monitor future change in the creek, whether natural or human-induced, a baseline of targeted species for the creek waters must be established as a “snapshot” of the Nacogdoches Lanana Creek …

Analysis Of Accounting Wages Within The Largest Cities Of Texas, Zuleima Espino, Delyla Frederick, Allyson Gallier, Halee Morehead

Undergraduate Research Conference

No abstract provided.

Sfa Weather Station-March 2015, Arthur Temple College Of Forestry And Agriculture, Stephen F. Austin State University

Weather Station Data

No abstract provided.

Biological Control Via "Ecological" Damping: An Approach That Attenuates Non-Target Effects, Rana D. Parshad, Kelly Black, Emmanuel Quansah, Matthew Beauregard

Faculty Publications

In this work we develop and analyze a mathematical model of biological control to prevent or attenuate the explosive increase of an invasive species population in a three-species food chain. We allow for finite time blowup in the model as a mathematical construct to mimic the explosive increase in population, enabling the species to reach “disastrous” levels, in a finite time. We next propose various controls to drive down the invasive population growth and, in certain cases, eliminate blow-up. The controls avoid chemical treatments and/or natural enemy introduction, thus eliminating various non-target effects associated with such classical methods. We refer …

Sfa Weather Station-February 2015, Arthur Temple College Of Forestry And Agriculture, Stephen F. Austin State University

Weather Station Data

No abstract provided.

Linking Sustainability To Quality Management And Firm Performance, Rajat Mishra, Randy Napier

Faculty Publications

Environmental management practices have evolved significantly over the past two decades. During that time, sustainable operations management practices have purportedly made positive contributions to overall firm performance. This paper develops two conceptual frameworks regarding the relationships among specific elements of environmental management, quality management, and firm performance. We suggest that innovation in quality management mediates the relationship between design for environment and firm performance, and that statistical process control techniques moderate the relationship between environmental management systems and firm performance. We identify future research possibilities, based on these frameworks, to inform scholarly research and practice in environmental management and quality …

The Schwartz Space: Tools For Quantum Mechanics And Infinite Dimensional Analysis, Jeremy Becnel, Ambar Sengupta

Faculty Publications

An account of the Schwartz space of rapidly decreasing functions as a topological vector space with additional special structures is presented in a manner that provides all the essential background ideas for some areas of quantum mechanics along with infinite-dimensional distribution theory.

Implementation Of Collaborative Learning As A High-Impact Practice In A Natural Resources Management Section Of Freshman Seminar, Matthew W. Mcbroom, Steven H. Bullard, David Kulhavy, Daniel R. Unger

Faculty Publications

Forestry and environmental science students enrolled in a one credit hour freshman seminar course participated in a land management evaluation and water quality sampling excursion using canoes and water sampling equipment. The purpose of this assessment was to engage students with hands-on, field based education in order to foster connections to their chosen profession and the resource. This culminated in poster symposium of the experience. Broad competency areas for high impact practices in natural resource management were emphasized for learning. Students were engaged in the exercise and commented that the project helped them develop a sense of place and forming …

Integrating Hands-On Undergraduate Research In An Applied Spatial Science Senior Level Capstone Course, David Kulhavy, Daniel R. Unger, I-Kuai Hung, David Douglass

Faculty Publications

A senior within a spatial science Ecological Planning capstone course designed an undergraduate research project to increase his spatial science expertise and to assess the hands-on instruction methodology employed within the Bachelor of Science in Spatial Science program at Stephen F Austin State University. The height of 30 building features estimated remotely with LiDAR data, within the Pictometry remotely sensed web-based interface, and in situ with a laser rangefinder were compared to actual building feature height measurements. A comparison of estimated height with actual height indicated that all three estimation techniques tested were unbiased estimators of height. An ANOVA, conducted …

Integrating Hands-On Undergraduate Research In An Applied Spatial Science Senior Level Capstone Course, David Kulhavy, Daniel Unger, I-Kuai Hung, David Douglass

Faculty Publications

A senior within a spatial science Ecological Planning capstone course designed an undergraduate research project to increase his spatial science expertise and to assess the hands-on instruction methodology employed within the Bachelor of Science in Spatial Science program at Stephen F Austin State University. The height of 30 building features estimated remotely with LiDAR data, within the Pictometry remotely sensed web-based interface, and in situ with a laser rangefinder were compared to actual building feature height measurements. A comparison of estimated height with actual height indicated that all three estimation techniques tested were unbiased estimators of height. An ANOVA, conducted …

Sfa Weather Station-January 2015, Arthur Temple College Of Forestry And Agriculture, Stephen F. Austin State University

Weather Station Data

No abstract provided.

Evaluation Of The Performance Of A Rural Municipal Wastewater Treatment Plant In Nacogdoches, East Texas (Usa) (Abstract), Kefa Karimu Onchoke, Michael Janusa, Salomey Asantewaa Sasu

Faculty Publications

The performance of a rural wastewater treatment facility, Nacogdoches Wastewater Treatment Plant

(NWWTP), in East Texas, USA, was assessed from January 2013 through June 2014. The elemental concentrations (Na, Mg, Ca, Ni, Pb, Mn, Cr, Mo, and Cu, Al, As, B, Ba, Ag, Cd, Fe, Hg, K, Se, Zn, Co, P, and S) were measured using inductively coupled plasma optical emission spectrometry. The anion concentrations (Br−, NO3- , NO2- , PO34-,F−, Cl−, and SO24−) were measured by ion chromatography. In general, the NWWTP was found efficient in removal to ≥ 96% for metals. The removal efficiency for anions was in …

Theoretical Examination Of Solvent And R Group Dependence In Gold Thiolate Nanoparticle Synthesis, Suzanne M. Neidhart, Brian M. Barngrover, Christine M. Aikens

Faculty Publications

The growth of gold thiolate nanoparticles can be affected by the solvent and the R group on the ligand. In this work, the difference between methanol and benzene solvents as well as the effect of alkyl (methyl) and aromatic (phenyl) thiols on the reaction energies and barrier heights is investigated theoretically. Density functional theory (DFT) calculations using the BP86 functional and a triple ζ polarized basis set show that the overall reaction favors methylthiol over phenylthiol with reaction energies of −0.54 and −0.39 eV in methanol, respectively. At the same level of theory, the methanol solvent is favored over the …

Prediction Of Nonradical Au (0)-Containing Precursors In Nanoparticle Growth Processes, Brian M. Barngrover, Timothy J. Manges, Christine M. Aikens

Faculty Publications

This density functional theory (DFT) investigation examines the formation of nonradical Au(0) species from the reduction of Au(I) species. The Au(I) complexes of interest are AuCl₂^–, AuBr₂^–, AuI₂^–, AuClPH₃, and AuCl(H)SCH₃⁽⁻⁾, which are precursors for gold nanoparticle and cluster formation. Reaction of two of the Au(I) species with a hydride results in ejection of two of the ligands and formation of Au₂ with two ligands still attached. AuX₂^– (where X = Cl, Br, or I) reactions eject two halides and form Au_{2 …}