Physical Sciences and Mathematics Commons^™

An Exploration In Ramsey Theory, Jake Weber

Dissertations and Theses @ UNI

We present several introductory results in the realm of Ramsey Theory, a subfield of Combinatorics and Graph Theory. The proofs in this thesis revolve around identifying substructure amidst chaos. After showing the existence of Ramsey numbers of two types, we exhibit how these two numbers are related. Shifting our focus to one of the Ramsey number types, we provide an argument that establishes the exact Ramsey number for h(k, 3) for k ≥ 3; this result is the highlight of this thesis. We conclude with facts that begin to establish lower bounds on these types of Ramsey …

On The Zeta Kirchhoff Index Of Several Graph Transformations, Danny Cheuk

Dissertations and Theses @ UNI

In this paper, we first derived the Ihara zeta function, complexity and zeta Kirchhoff index of the k-th semitotal point graph (of regular graphs), a construction by Cui and Hou [5], where we create triangles for every edge in the original graph. Then, we extend the construction to the creation of equilaterals and polygons.

We also derived the zeta Kirchhoff indices for numerous graph transformations on regular graphs, and some selected families of graphs.

At the end, a data summary is provided for enumeration computed on simple connected md2 graphs up to degree 10.

Analysis Of A Paleoglacier Reconstruction Model For Valley Glaciers Of The Wind River Range, Wyoming, Taylor Rae Garton

Dissertations and Theses @ UNI

Various approaches, ranging from in-field morphological reconstructions to more technology-based modelling practices allow us to reconstruct and understand the long-term geomorphic evolution of landscapes. The study of paleo-environments by reconstruction can also give us profound insight into paleo-climate. A new model, GlaRe (Glacial Reconstruction), has been introduced into the alpine glacier modeling community to facilitate glacier reconstruction. In this research the mathematical equations representing the basal shear stress parameter are tested to determine the applicability of the GlaRe model to alpine glaciers in the American West. Known ages and extents of past glacier advances were used to test the reconstructions …

Analysis Of Ambient Particulate Concentration Near A Coal Storage Pile, Jennifer Wittenburg

Dissertations and Theses @ UNI

Fugitive dust sources such as aggregate storage piles contribute significantly to the total suspended particulate levels in the ambient air. Particulate levels are monitored and regulated by the Environmental Protection Agency to protect public health and welfare. This study monitored particulate concentrations in the ambient air near a coal storage pile. Air samplers and weather stations were placed at two locations, one to the north of the pile and one to the south of the pile, and were used to collect particulate and weather related data.

The data were analyzed to determine the origin of the particulate and to identify …

Properties Of Left-Separated Spaces And Their Unions, Eric Scheidecker

Dissertations and Theses @ UNI

Left-separated spaces are topological spaces which can be well ordered such that every initial segment is closed. In this paper, we examine what topological properties imply left-separation, and under what circumstances left-separation is preserved by unions. We also introduce several known theorems regarding elementary submodels as they are one of the primary tools that we use. We prove that for a topological space X;

1. If X has a point-countable base, then X is left-separated if and only if X has closed intersection with any elementary submodel M such that X ∈ M.

2. If every elementary submodel …

The Programmatic Manipulation Of Planar Diagram Codes To Find An Upper Bound On The Bridge Index Of Prime Knots, Genevieve R. Johnson

Dissertations and Theses @ UNI

The “bridge index” of a knot is the least number of maximal overpasses taken over all diagrams of the knot. A naïve method to determine the bridge index of a knot is to perform Reidemeister moves on diagrams of the knot, and this method quickly becomes tedious to implement by hand. In this paper, we introduce a sequence of Reidemeister moves which we call a “drag the underpass” move and prove how planar diagram codes change as Reidemeister moves are performed. We then use these results to programatically perform Reidemeister moves using Python 2.7 to calculate an upper bound on …

A Survey Of Butterfly Diagrams For Knots And Links, Mark Ronnenberg

Dissertations and Theses @ UNI

A “butterfly diagram” is a representation of a knot as a kind of graph on the sphere. This generalization of Thurston’s construction of the Borromean rings was introduced by Hilden, Montesinos, Tejada, and Toro to study the bridge number of knots. In this paper, we study various properties of butterfly diagrams for knots and links. We prove basic some combinatorial results about butterflies and explore properties of butterflies for classes of links, especially torus links. The Wirtinger presentation for the knot group will be adapted to butterfly diagrams, and we translate the Reidemeister moves for knot diagrams into so-called “butterfly …

The Effects Of Blended Learning On Critical Thinking In A High School Earth Science Class, Renee Nicole Borglum

Dissertations and Theses @ UNI

This study analyzed the effects of differing levels of technology use in a high school Earth Science class on student performance on the Classroom Test of Scientific Reasoning (CTSR). Blended learning manipulates the combination of hands-on activities, classroom discussions, online discussions, interactive simulations and a variety of assessments that engage, instruct and assess student learning. Critical thinking is the set of skills and dispositions that foster problem solving, reasoning ability and selfregulation. The increasing use of technology in the classroom and fluctuation of content standards prompted this research. The results have implications for the classroom teacher of a wide range …

Three Men In The Wilderness: Ideas And Concepts Of Nature During The Progressive Era With Theodore Roosevelt, Gifford Pinchot And John Muir, Jeffrey A. Duke

Dissertations and Theses @ UNI

When I began this research in the summer of 2014, I endeavored to find out how Americans comprehended nature in the Progressive Era. By the Progressive Era the historian Frederick Jackson Turner declared the frontier to be closed. This notion that no wide open spaces remained to be conquered altered the American people’s attitude towards nature. The perspectives of three men who were at the forefront of environmental policy illustrate how America’s understanding of nature had changed. These three men were twenty-sixth President Theodore Roosevelt, professional forester Gifford Pinchot and naturalist John Muir. Describing the similarities and differences in these …

Some Convergence Properties Of Minkowski Functionals Given By Polytopes, Jesse Moeller

Dissertations and Theses @ UNI

In this work we investigate the behavior of the Minkowski Functionals admitted by a sequence of sets which converge to the unit ball ‘from the inside’. We begin in R 2 and use this example to build intuition as we extend to the more general R n case. We prove, in the penultimate chapter, that convergence ‘from the inside’ in this setting is equivalent to two other characterizations of the convergence: a geometric characterization which has to do with the sizes of the faces of each polytope in the sequence converging to zero, and the convergence of the Minkowski functionals …

Reconciling The Two Cultures : A Case Study Of The University Of Northern Iowa, Elizabeth Ann Collins

Dissertations and Theses @ UNI

In 1959, chemist and author Charles Percy Snow gave a Rede Lecture at the University of Cambridge in which he named “Two Cultures”—the sciences and the humanities—which, according to his experience as someone who worked in both, were at odds with one another. His words elicited impassioned responses from critics who either agreed with Snow, believing this to be a detriment to society, or vehemently disagreed, believing Snow’s statements to be unfounded, and even antagonistic. This conversation, which had also found relevance in the United States, continues to be important today, and has changed over the years as institutions of …

Understanding The Impact Of Vegetation On Surface Roughness Length For Enhancing Wind Resource Characterization In Iowa, Andrei Vladimirovich Kushkin

Dissertations and Theses @ UNI

Wind energy development shows a rapid growth in the United States. This renewable energy source not only mitigates environmental concerns by reducing greenhouse gas emission, but also provides energy independence. Wind is clean and abundant, and is one of the most promising sources of alternative energy. Iowa is among the top wind energy producers in the nation, it is third by installed capacity and first in per capita production. In order to utilize wind resource potential most efficiently, accurate wind resource assessments are required. Changes in the aerodynamic characteristics of a site can have a major influence on the wind …

A Study Of College Student Attitudes And Behaviors Related To Recycling, Mark Allen Wilcox

Dissertations and Theses @ UNI

There is an abundance of research on environmental attitudes and recycling; specifically however college students are very under represented. This population is one that is very important as these individuals will be the ones making decisions, privately and politically, with regards to recycling programs in their communities. By understanding their attitudes and behaviors in college, those designing recycling programs can develop and modify programs to suit their needs, and education programs can be prepared to better inform these individuals. The purpose of this study was to study the attitudes and behaviors of college students related to recycling. To accomplish this, …

Calculating Nutrient Loads From Four Tributaries Of The Cedar River In Iowa, Jacob Donaghy

Dissertations and Theses @ UNI

A study was done on four tributaries to the Cedar River to determine nutrient concentrations, loads, and the contribution of each watershed per unit area. The Cedar River watershed is primarily agricultural land and extends from southern Minnesota to southeastern Iowa. Past studies have indicated that this watershed is a major contributor of nitrate to the Gulf of Mexico via the Mississippi River. This eutrophication is the cause of the hypoxic Gulf. From April 13, 2010-September 21, 2010 samples were taken from four tributaries of the Cedar River. Discharge data were taken from USGS gaging stations along with a method …

Developing Rating Curves In A Small Iowa Watershed To Evaluate Nutrient Loading In Streams, Jennifer Mary Shepeck

Dissertations and Theses @ UNI

Dry Run Creek, a tributary to the Cedar River in northeast Iowa, is a watershed under high pressure from the surrounding region. With its headwaters located in farm fields and urban drainage ditches, it is subject to flash flooding and erosion and is on the DNR’s list of impaired waters. Dry Run Creek is similar to other small watersheds across eastern Iowa. As tributaries to the larger rivers that eventually flow into the Mississippi River and then to the Gulf of Mexico, they are significant contributors to the nutrient loading causing the hypoxia in the Gulf. The purpose of this …

D-Spaces In Infinite Products Of Ordinals, Duncan Wright

Dissertations and Theses @ UNI

William Fleissner and Adrienne Stanley showed that, in finite products of ordinals, the following are equivalent: 1. X is a D-space. 2. X is metacompact. 3. X is metalindel¨of. 4. X does not contain a closed subset which is homeomorphic to a stationary subset of a regular, uncountable cardinal. In this paper we construct a counterexample that shows that this equivalence does not extend to infinite products of ordinals. We also introduce a new property, club-separable, which we show implies D for subsets of ωω1. We hope that club-separable will be able to replace property (4) above in order to …

Development Of A Multi-Mode Self-Adaptive Algorithm To Create An Efficient Wireless Network On A University Campus, Melanie L. Abbas

Dissertations and Theses @ UNI

The expanding use of ubiquitous computing has created a significant demand on existing network infrastructures. The demands of voice, video, and data on the same medium require a quality of service (QoS) at a level acceptable to users. Many network providers simply scale their networks to increase bandwidth and hardware to deal with the increasing demands. However, a network may still reach its design limits with peak traffic or malicious overuse of resources. In addition, with technology changing at a rapid pace, it is difficult to provide sufficient staffing to monitor and adjust the network settings to avoid issues during …

Liquid Sorption Properties And Structural Changes Of Metal-Organic Frameworks Of Cobalt Nitrate And 4,4'-Bipyridine, Kathryn Mauger-Sonnek

Dissertations and Theses @ UNI

Metal-organic frameworks consist of metal ions connected by organic ligands. When the metal ions and organic ligands link together in the right geometry, polymeric and infinite 1D chains or 2D and 3D networks are formed. Porous metal-organic frameworks were synthesized from the organic ligand 4,4′-bipyridine (bpy) and cobalt(II) nitrate. The metal-organic frameworks synthesized in this study grew into both a previously known 2D bilayer structure, [Co2(bpy)3(NO3)4]n, and a new, orange 1D chain structure, [Co(bpy)NO3)2(H2O)2]n, within ethanol. It was found that the presence of water was the main factor of causing formation of the orange 1D chain crystals. Drying the orange …

Temporal Dynamics Of Nutrient Flux Across Hydrologic Unit Boundaries, Md. Aminul Haque

Dissertations and Theses @ UNI

The study was done in Dry Run Creek watershed, a small sub-urban watershed in the northwestern part of Black Hawk County, Iowa. Different hydrologic units like, wetland, agricultural area, urban area, and stream channels were compared in terms of nutrient transport. Soil, surface water, and groundwater samples were collected from May, 2012 to October, 2012. Among the hydrologic units, agricultural land has the highest organic matter percentages, infiltration rate, soil nitrate, and total phosphorus. High infiltration rate and amount of nutrients in agricultural soil made those areas more vulnerable to vertical infiltration of pollutants. Agricultural and urban soils had similar …

Einstein Metrics On Piecewise-Linear Three-Spheres, Kyle Pitzen

Dissertations and Theses @ UNI

Einstein metrics on manifolds are in some ways the "best" or most symmetric metrics those manifolds will allow. There has been much work on these metrics in the realm of smooth manifolds, and many results have been published. These results are very difficult to compute directly, however, and so it is helpful to consider piecewise-linear approximations to those manifolds in order to more quickly compute and describe what these metrics actually look like. We will use discrete analogues to powerful preexisting tools to do analysis on two particular triangulations of the three dimensional sphere with the intent of finding Einstein …

Understanding The Critical Role Of A Wetland In Maintaining The Ecosystem: A Case Study, Sushil Tuladhar

Dissertations and Theses @ UNI

Beaver Valley Wetland in north-east Iowa was studied to determine its functionality in filtering incoming contaminants from the surrounding agricultural fields. The study was conducted from May through November of 2011. Altogether 78 water samples (from 13 sites), 84 soil samples (from 14 sites), and some sediment samples were collected for chemical analysis. Heavy metals in three different soil categories, such as surface, 6” deep, and sediments were found to be at or below the acceptable concentrations, indicating no immediate concern for metal toxicity in the wetland environment. The chemical tracers that were used to study the sub-surface flow regime …

Modeling And Measuring The Dispersion Of Odors From Hog Confinements, François Béra

Dissertations and Theses @ UNI

A comparison was made between predicted and measured odor concentration downwind of two hog finishing confinements. Two Gaussian dispersion models, STINKBAK and AERMOD, were used. The experimental cases examined odor emanating from a mechanically-ventilated facility and a curtain-sided facility during summer 2003. A field olfactometer was used to measure odor concentration. The odor concentrations served as input to STINKBAK, which then estimated the odor emission rate from the confinement. AERMOD used this emission rate and other meteorological data to predict the peak concentration of odor around the confinement over the sampling hour.

The calculated odor emission rates are slightly higher …

A Comparison Of Land Use And Nonpoint Source Pollution In The Cedar River Tributaries In Iowa, Chad Levi Fields

Dissertations and Theses @ UNI

A comparative water analysis on major Cedar River tributaries was conducted to determine nutrient and sediment concentration, nutrient loads, and watershed land use during the spring and summer of 2002. The Cedar River watershed is located on a primarily agricultural land, and has a drainage area of20,242 km2. The watershed extends from southern Minnesota to southeastern Iowa, where it joins the Iowa River which subsequently flows into the Mississippi River. Past studies have concluded that the Cedar River contributes much of the nutrients entering the Mississippi River and the Gulf of Mexico. These nutrients then contribute to the zone of …

An Analysis Of A Radio Frequency Sensor As A Means To Remotely Sense Selected Surface Topographies In An Agriculture Environment, Barry Michael Alexia

Dissertations and Theses @ UNI

Remote sensing is the science and art of obtaining information about an object, area or phenomenon through the analysis of data acquired by a device that is not in contact with the object, area, or phenomenon under investigation. The remotely sensed data can be of many forms, including variations in force distribution, acoustic wave distribution, or electromagnetic energy distribution.Information thus acquired can be used for observing,monitoring, and studying planetary surfaces and environments.

Because there are many ways to acquire data about targets of interest, there are many types of remote sensors that can be used, including visible, infrared, and active …

The Coupling Of Biotechnology With Electrochemistry: Electrodenitrification Of Water Using The Enzyme Nitrate Reductase, Cyril Geyer

Dissertations and Theses @ UNI

Nitrate is a worldwide contaminant that causes environmental (eutrophication) and human health (methemoglobinemia, cancers) concerns. Very few techniques are available to eliminate it from natural environment and they suffer from major drawbacks, such as production of unwanted byproducts (toxins or brine). The electrochemical reduction of nitrate on any electrode is relatively slow and catalysts or electron mediators are needed. The goal of this project was to develop a new process that could overcome these disadvantages. The project demonstrates the feasibility of using an enzyme, nitrate reductase, and a mediator, methyl viologen to transfer the electrons from the electrode to nitrate, …

Photodecomposition Of Crystal Violet Dye In Water Solution And Suspensions Of Metal Oxides, Tatiana Yurievna Zakharian

Dissertations and Theses @ UNI

Photodecomposition and photodecolorization of crystal violet dye were studied in water solution, hydrogen peroxide solution and suspensions of metal oxides. Spectroscopic evidence for the formation of methylated pararosanilines and demethylated derivatives of Michler's ketone as the reaction intermediates was obtained for the photodecomposition of crystal violet in water solution. The mechanism of formation of the intermediates was discussed in terms of charges of individual atoms calculated using Spartan software.

Photooxidation of crystal violet was shown to occur faster in hydrogen peroxide solution due to the higher oxidation potential of hydrogen peroxide and hydroxyl radicals. A mechanism similar to photooxidation in …

Inactivation Of Soybean Peroxidase During Sodium Azide Oxidation: A Comparative Study, Mohamed Yehia Zakaria Aboul Eish

Dissertations and Theses @ UNI

Azide ion is a mechanism-based inactivator of a number of peroxidases. However, there are often variations in the manner in which inactivation occurs. Soybean Peroxidase (SBP) is found in the plant's seed coat. Unlike many other peroxidases, a single enzyme rather than several isozymes are produced thus making more simple the purification and characterization of the enzyme. In this research it was shown that, as with other peroxidases, SBP is inactivated by azide during turnover. During azide oxidation SBP forms a ferrous-NO intermediate. In this respect, SBP is similar to the lignin peroxidases from Phanerochaete chrysosporium which also form ferrous-NO …

Network Security: An Evaluation Of Security Policies And Firewall Implementations, Melanie L. Abbas

Dissertations and Theses @ UNI

This paper begins focusing on network security issues. The areas of physical security, access security, and connection security are explored. Connection security provides the biggest need for improvement in the entire security field. This type of security is managed best with firewall implementations. Various firewall models are discussed.

Software evaluations were performed on three different commercial Internet security tools. The software was compared on the basis of ease of installation, functionality, level of security provided, and output available. In summary, the value of the firewall is dependent on the need to implement a firewall in an organization.

However, a security …

Fuzzy Logic: An Analysis Of Logical Connectives And Their Characterizations, John F. Hamman

Dissertations and Theses @ UNI

The focus of this thesis is to determine exactly which functions serve as appropriate fuzzy negation, conjunction and disjunction functions. To this end, the first chapter serves as motivation for why fuzzy logic is needed, and includes an original demonstration of the inadequacy of many valued logics to resolve the sorites paradox. Chapter 2 serves as an introduction to fuzzy sets and logic. The canonical fuzzy set of tall men is examined as a motivating example, and the chapter concludes with a discussion of membership functions.

Four desirable conditions of the negation function are given in Chapter 3, but it …

Radon Reduction, Improvement Of Indoor Air Quality, And Energy Savings Through An Original Solar Ventilation System, Heather E. Rhoads

Dissertations and Theses @ UNI

This study evaluated the improvement of indoor air quality and energy savings achieved, by an original solar ventilation system installed at test sites exhibiting elevated radon levels. Conventional residential energy conservation measures that limit air exchange rates between the indoors and outdoors have been shown to increase concentrations of radioactive radon decay products as well as other indoor air contaminants. Growing concern about radon lung cancer risks, carbon monoxide poisoning, and the "sick building syndrome" have increased demand for improved indoor air quality. Due to added heating and cooling loads, ventilation generally incurs substantial installation and operational costs. All commercially …