Physical Sciences and Mathematics Commons^™

Global Sampling Of The Photochemical Reaction Paths Of Bromoform By Ultrafast Deep-Uv Through Near-Ir Transient Absorption And Ab Initio Multiconfigurational Calculations, Alexander N. Tarnovsky, S. K. Pal, A. S. Mereshchenko, E. V. Butaeva, Patrick Z. El-Khoury

Chemistry Faculty Publications

Ultrafast deep-ultraviolet through near infrared (210-950 nm) transient absorption spectroscopy complemented by ab initio multiconfigurational calculations offers a global description of the photochemical reaction pathways of bromoform following 255-nm excitation in methylcyclohexane and acetonitrile solutions. Photoexcitation of CHBr3 leads to the ground-state iso-CHBr3 product in a large quantum yield (∼35), formed through two different mechanisms: concerted excited-state isomerization and cage-induced isomerization through the recombination of the nascent radical pair. These two processes take place on different time scales of tens of femtoseconds and several picoseconds, respectively. The novel ultrafast direct isomerization pathway proposed herein is consistent with the occurrence of …

Single-Cell Imaging And Spectroscopic Analyses Of Cr(Vi) Reduction On The Surface Of Bacterial Cells, Yuanmin Wang, Papatya C. Sevinc, Sara M. Belchik, Jim Fredrickson, Liang Shi, H. Peter Lu

Chemistry Faculty Publications

We investigate the single-cell reduction of toxic Cr(VI) by the dissimilatory metal-reducing bacterium Shewanella oneidensis MR-1 (MR-1), an important bioremediation process, using Raman spectroscopy and scanning electron microscopy (SEM) combined with energy-dispersive X-ray spectroscopy (EDX). Our experiments indicate that the toxic, highly soluble Cr(VI) can be efficiently reduced to less toxic, nonsoluble Cr2O3 nanoparticles by MR-1. Cr2O3 is observed to emerge as nanoparticles adsorbed on the cell surface and its chemical nature is identified by EDX imaging and Raman spectroscopy. Co-localization of Cr2O3 and cytochromes by EDX imaging and Raman spectroscopy suggests a terminal reductase role for MR-1 surface-exposed cytochromes …

Easy Steps To Reduce Your Energy Bill, B. Thomas, Brett Tingey, Roslynn Brain

Environment and Society Faculty Publications

Fossil fuels supply most of Utah’s energy needs. Any process using fossil fuels, however, emits carbon dioxide (CO2), mercury, and oftentimes other contaminants that stress Utah’s beautiful natural resources (Dresselhaus & Thomas, 2001). Most electricity in Utah is fueled by coal-fired power, which adds mercury to our air and waterways. Increased mercury in ducks and fish have resulted in restrictions for Utah family pastimes, such as fishing and duck hunting. In 2010, 23% of energy consumption in the United States was residential, totaling 22.2 quadrillion Btu (EIA, 2010). A quadrillion Btu is about equal to the amount of energy in …

Combined Self-Consistent-Field And Spin-Flip Tamm-Dancoff Density Functional Approach To Potential Energy Surfaces For Photochemistry, Xuefei Xu, Samer Gozem, Massimo Olivucci, Donald G. Truhlar

Chemistry Faculty Publications

We present a new approach to calculating potential energy surfaces for photochemical reactions by combining self-consistent-field calculations for single-reference ground and excited states with symmetry-corrected spin-flip Tamm-Dancoff approximation calculations for multireference electronic states. The method is illustrated by an application with the M05-2X exchange-correlation functional to cis-trans isomerization of the penta-2,4-dieniminium cation, which is a model (with three conjugated double bonds) of the protonated Schiff base of retinal. We find good agreement with multireference configuration interaction-plus-quadruples (MRCISD+Q) wave function calculations along three key paths in the strong-interaction region of the ground and first excited singlet states.

Controlling Factors On Bedrock River Sinuosity In The Eastern Tibetan Plateau, Lydia Curliss

Honors Papers

Average sinuosity of bedrock rivers across the eastern Tibetan Plateau (including the Yangtze, Mekong, Salween, Irrawaddy, and Tsang Po) ranges from 1.20-1.41. From 25°-30°N, sinuosity marginally increases east to west; over the entire distance of each river, sinuosity increases north to south. Increases in sinuosity parallel a regional tectonic gradient in an area with a marginal climate gradient. Several past studies correlate sinuous bedrock rivers in mountainous regions with gradients in climate, arguing that landslides are the main mechanism by which bedrock rivers increase sinuosity. Other studies find correlations between tectonics and increasing landslide frequency. To investigate the role of …

Geophysical Investigation And Assessment Of The Rye Patch Known Geothermal Resource Area, Rye Patch, Nevada, Mark Richmond Mcdonald

Theses and Dissertations

A gravity and ground-based magnetic survey was conducted at the Rye Patch Known Geothermal Resource Area located at Rye Patch, Nevada. The purpose of the study was to attempt to further delineate the geothermal reservoir and/or to identify potential drilling targets. The survey consisted of collecting data at 264 new stations to augment data from 203 stations collected in 2008. Information from previous seismic, aeromagnetic and geochemical investigations was also examined and incorporated. Filtering methods including removal of a polynomial trend surface and wavelength filtering were utilized on the gravity data to remove the strong regional overprint caused by the …

On Characterizations Of Exponential Distribution Through Order Statistics And Record Values With Random Shifts, M. Ahsanullah, Imtiyaz A. Shah, George Yanev

School of Mathematical and Statistical Sciences Faculty Publications and Presentations

Distributional relations of the form Y d= X +T where X, Y, and T are record values or order statistics and the random translator T is independent from X are considered. Characterizations of the exponential distribution when the ordered random variables are non-neighboring are proved. Corollaries for Pareto and power function distributions are also derived.

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 …

Search For Long-Lived Gravitational-Wave Transients Coincident With Long Gamma-Ray Bursts, J. Aasi, Daniel Bessis, Teviet Creighton, Mario C. Diaz, Soma Mukherjee, Malik Rakhmanov, Volker Quetschke, Joseph D. Romano, Robert Stone, Lappoon R. Tang, Cristina V. Torres

Physics and Astronomy Faculty Publications and Presentations

Long gamma-ray bursts (GRBs) have been linked to extreme core-collapse supernovae from massive stars. Gravitational waves (GW) offer a probe of the physics behind long GRBs. We investigate models of long-lived (~10–1000 s) GW emission associated with the accretion disk of a collapsed star or with its protoneutron star remnant. Using data from LIGO’s fifth science run, and GRB triggers from the Swift experiment, we perform a search for unmodeled long-lived GW transients. Finding no evidence of GW emission, we place 90% confidence-level upper limits on the GW fluence at Earth from long GRBs for three waveforms inspired by a …

A Tunable Electromagnetic Band-Gap Microstrip Filter, Greg A. Lancaster

Master's Theses

In high frequency design, harmonic suppression is a persistent struggle. Non-linear devices such as switches and amplifiers produce unwanted harmonics which may interfere with other frequency bands. Filtering is a widely accepted solution, however there are various shortcomings involved. Suppressing multiple harmonics, if desired, with traditional lumped element and distributed component band-stop filters requires using multiple filters. These topologies are not easily made tunable either. A new filter topology is investigated called Electromagnetic Band-Gap (EBG) structures.

EBG structures have recently gained the interest of microwave designers due to their periodic nature which prohibits the propagation of certain frequency bands. EBG …

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 …

A Study In Merger Induced Galaxy Evolution Through Post-Starburst Systems, Zachary Dean Griffith

Honors Program Theses

We discuss an optical study of a triple galaxy system at a redshift of 0.06. In optical images from Data Release 7 of the Sloan Digital Sky Survey (SDSS), the system consists of a close pair plus another galaxy at a projected distance of 35 kpc. Tidal features extending at least 30 kpc are visible to the southeast of both the galaxy pair and the third member of the system, suggesting significant interaction. One of the the pair and the more isolated galaxy are low-luminosity radio sources. The lone galaxy appears extended in a radio map from the FIRST survey. …

Clean Up Our Home: Ellen Swallow Richards' Human Ecology And Emerging Environmental Ideologies, 1890-1915, Raeann Lillian Swanson

Honors Program Theses

In the late 1880s, after years of study and hard work, Ellen Richards began publishing her ideas on the home and the natural and urban environment. She called for the knowledge of basic scientific principles to be available to everyone. She believed that ignorance was holding back the public from altering their environment to make life healthier, happier, and safer. Over one hundred years later, Malcolm Gladwell wrote the book The Tipping Point. In his book, Gladwell explores the Broken Windows Theory that social scientists claimed they developed in the 1980s. The Broken Windows Theory states that there is a …

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 …

Analysis Of Mathematical Descriptions Of Gravitational Microlensing, Sarah Michelle Pearce

Honors Program Theses

This thesis will provide an analysis of some aspects of gravitational microlensing and the quantitative descriptions used to model the astrophysical systems involved. One aspect of the mathematical description of micro lensing events that is investigated in this thesis is the evolution of micro lensing equations from the formalism of general relativity. The derivation of these equations from those governing general relativity and the bending of light rays in geometric optics is explicitly determined. The relationship between the equations used to model events and the light curves produced is investigated. The effect of degeneracies in the mathematical equations used to …

Model For Acid-Base Chemistry In Nanoparticle Growth (Mabnag), Taina Yli-Juuti, Kelley Barsanti, L. Hildebrandt Ruiz, Antti-Jussi Kieloaho, U. Makkonen, Tuukka Petäjä, Taina Ruuskanen, Markku Kulmala, Ilona Riipinen

Civil and Environmental Engineering Faculty Publications and Presentations

Climatic effects of newly-formed atmospheric secondary aerosol particles are to a large extent determined by their condensational growth rates. However, all the vapours condensing on atmospheric nanoparticles and growing them to climatically relevant sizes are not identified yet and the effects of particle phase processes on particle growth rates are poorly known. Besides sulfuric acid, organic compounds are known to contribute significantly to atmospheric nanoparticle growth. In this study a particle growth model MABNAG (Model for Acid-Base chemistry in NAnoparticle Growth) was developed to study the effect of salt formation on nanoparticle growth, which has been proposed as a potential …

Understanding And Managing Karst Water Resources In Belize: Case Studies Of Both Past And Present In A Changing Climate, Jason S. Polk, Leslie North, Ben Miller, Jonathan Oglesby, Kegan Mcclanahan, Lowell Neeper, Aaron Holland, Bernie Strenecky

Earth, Environmental, and Atmospheric Sciences Faculty Publications

Belize is a developing country that faces water resource issues in the forms of both quality and quantity, stemming from a long history of environmental stress and population threats, from the ancient Maya to present. Belize’s karst landscape, which comprises a large part of the country from the coast to the Maya Mountains, is characterized by springs, caves, sinkholes, and aquifers systems formed from the dissolution of carbonate (limestone, dolomite) rock. This research presents several different case studies, spanning from the ancient Maya and issues with drought to modern communities that rely on groundwater resources quickly being depleted. Past drought …

Room-Temperature Vibrational Properties Of The Bimn2o5 Mullite, F Silva Júnior, C. Paschoal, R. Almeida, R. Moreira, W. Paraguassu, M. Castro Junior, A. Ayala, Z. Kann, Michael Lufaso

Michael W. Lufaso

Raman and infrared spectroscopic measurements were performed and combined with lattice dynamics simulations in order to describe the room temperature vibrational properties of the BiMn2O5 mullite ceramic. A total of 13 Raman active modes and 19 infrared active modes were observed. The lattice dynamics simulation was used to assign the observed bands and to discuss the phonon behavior of this compound. The obtained dielectric constant and unloaded quality factor parameters for BMO ceramic obtained from the infrared data suggest the applicability of the BiMn2O5 as a possible candidate to microwave applications.

Genesee River Watershed Project. Volume 3. Water Quality Analysis Of The Honeoye Creek Watershed: Nutrient Concentration And Loading, Identification Of Point And Nonpoint Sources Of Pollution, Total Maximum Daily Load, And An Assessment Of Management Practices Using The Soil Water Assessment Tool (Swat) Model. A Report To The Usda., Joseph Makarewicz, Theodore Lewis, Blake Snyder

Joseph C Makarewicz

No abstract provided.

Getting To The Source: Where Does Wikipedia Get Its Information?, Heather Ford, Shilad Sen, David Musicant, Nathaniel Miller

Shilad Sen

No abstract provided.

On The Exact Size Of Multiple Comparison Tests, Chris Lloyd

Chris J. Lloyd

No abstract provided.

Pedagogy Of Vulnerability, Edward Brantmeier, A. Dean

Edward J. Brantmeier

No abstract provided.

Recalibrating Aeolian Sand Transport Models, Douglas Sherman, Bailiang Li, Jean Ellis, Eugene Farrell, Luis Maia, Helena Granja

Jean Taylor Ellis

No abstract provided.

Detrital Zircon Provenance Of The Proterozoic Midcontinent Rift, Lake Superior Region, Usa, John Craddock, A Konstantinou, J. Vervoort, K. Wirth, C. Davidson, L. Finley-Blasi, N. Juda, E. Walker

John Craddock

No abstract provided.

Sharing A Vision For Biodiversity Conservation And Agriculture, John Quinn

John E Quinn

No abstract provided.

Instrumental Variable Analyses: Exploiting Natural Randomness To Understand Causal Mechanisms, Theodore Iwashyna, Edward Kennedy

Edward H. Kennedy

Instrumental variable analysis is a technique commonly used in the social sciences to provide evidence that a treatment causes an outcome, as contrasted with evidence that a treatment is merely associated with differences in an outcome. To extract such strong evidence from observational data, instrumental variable analysis exploits situations where some degree of randomness affects how patients are selected for a treatment. An instrumental variable is a characteristic of the world that leads some people to be more likely to get the specific treatment we want to study but does not otherwise change thosepatients’ outcomes. This seminar explains, in nonmathematical …

Effects Of Fluctuating Energy Input On The Small Scales In Turbulence, Greg Voth

Greg A. Voth

In the standard cascade picture of three-dimensional turbulent fluid flows, energy is input at a constant rate at large scales. Energy is then transferred to smaller scales by an intermittent process that has been the focus of a vast literature. However, the energy input at large scales is not constant in most real turbulent flows. We explore the signatures of these fluctuations of large-scale energy input on small-scale turbulence statistics. Measurements were made in a flow between oscillating grids, with Taylor Reynolds number up to 262, in which temporal variations in the large-scale energy input can be introduced by modulating …

A New, Richly Fossiliferous Member Comprised Of Tidal Deposits In The Upper Cretaceous Maevarano Formation, Northwestern Madagascar, Raymond Rogers, David Krause, Sophia Kast, Madeline Marshall, Lydia Rahantarisoa, Colin Robbins, Joseph Sertich

Raymond Rogers

No abstract provided.

Improved Cardiovascular Risk Prediction Using Nonparametric Regression And Electronic Health Record Data, Edward Kennedy, Wyndy Wiitala, Rodney Hayward, Jeremy Sussman

Edward H. Kennedy

Use of the electronic health record (EHR) is expected to increase rapidly in the near future, yet little research exists on whether analyzing internal EHR data using flexible, adaptive statistical methods could improve clinical risk prediction. Extensive implementation of EHR in the Veterans Health Administration provides an opportunity for exploration. Our objective was to compare the performance of various approaches for predicting risk of cerebrovascular and cardiovascular (CCV) death, using traditional risk predictors versus more comprehensive EHR data. Regression methods outperformed the Framingham risk score, even with the same predictors (AUC increased from 71% to 73% and calibration also improved). …

Meridional Shifts Of The Atlantic Intertropical Convergence Zone Since The Last Glacial Maximum, J. Arbuszewski, P. Demenocal, C. Cleroux, Louisa Bradtmiller, A. Mix

Louisa I. Bradtmiller

No abstract provided.