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Full-Text Articles in Physical Sciences and Mathematics

Intrinsic Tame Filling Functions And Other Refinements Of Diameter Functions, Andrew Quaisley May 2023

Intrinsic Tame Filling Functions And Other Refinements Of Diameter Functions, Andrew Quaisley

Department of Mathematics: Dissertations, Theses, and Student Research

Tame filling functions are quasi-isometry invariants that are refinements of the diameter function of a group. Although tame filling functions were defined in part to provide a proper refinement of the diameter function, we show that every finite presentation of a group has an intrinsic tame filling function that is equivalent to its intrinsic diameter function. We then introduce some alternative filling functions—based on concepts similar to those used to define intrinsic tame filling functions—that are potential proper refinements of the intrinsic diameter function.

Adviser: Susan Hermiller and Mark Brittenham


Prefix-Rewriting: The Falsification By Fellow Traveler Property And Practical Computation, Ash Declerk May 2023

Prefix-Rewriting: The Falsification By Fellow Traveler Property And Practical Computation, Ash Declerk

Department of Mathematics: Dissertations, Theses, and Student Research

The word problem is one of the fundamental areas of research in infinite group theory, and rewriting systems (including finite convergent rewriting systems, automatic structures, and autostackable structures) are key approaches to working on the word problem. In this dissertation, we discuss two approaches to creating bounded regular convergent prefix-rewriting systems.

Groups with the falsification by fellow traveler property are known to have solvable word problem, but they are not known to be automatic or to have finite convergent rewriting systems. We show that groups with this geometric property are geodesically autostackable. As a key part of proving this, we …


Magnetic Properties Of Polycrystalline Spinel Oxides From Solid State Reaction, Camden Olds May 2023

Magnetic Properties Of Polycrystalline Spinel Oxides From Solid State Reaction, Camden Olds

Honors Theses

Spinel crystal materials of nickel, cobalt, and iron oxides have seen abundant research for their strong conductivity, ferromagnetic and ferroelectric properties, and their catalytic uses. These can be synthesized by a number of means. This project explores the use of the solid state synthesis method, which benefits from simplicity, of this family of materials, looking for interesting phase shift lines in the triangle between of varying compositions of these three metals.

Nickel cobaltite and other related spinels were synthesized from two different solid state approaches and characterized using XRD and SQUID magnetometry. The range 0.5-0.6 of molar ratios of nickel …


Assessment Of Bridge Pier Response To Fire, Vehicle Impact, And Air Blast, Chen Fang, Qusai Alomari, Daniel G. Linzell May 2023

Assessment Of Bridge Pier Response To Fire, Vehicle Impact, And Air Blast, Chen Fang, Qusai Alomari, Daniel G. Linzell

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Highway bridges exposed to intentional or unintentional fire followed by combined vehicle impact and air blast are at risk of significant damage and, possibly, collapse. Limited studies examining the complex effects of these extreme demands on bridge support elements and parametrizing their response and damage are found in the open literature. Research that is presented is part of an ongoing numerical investigation examining round, multi-column, reinforced concrete (RC), bridge pier behavior subject to multi-hazard scenarios involving fire, vehicle impact, and air blast. Detailed nonlinear finite element analysis models of single columns and multi-column piers supported by a pile foundation system …


Leveraging Aruco Fiducial Marker System For Bridge Displacement Estimation Using Unmanned Aerial Vehicles, Mohamed Aly May 2023

Leveraging Aruco Fiducial Marker System For Bridge Displacement Estimation Using Unmanned Aerial Vehicles, Mohamed Aly

Department of Computer Science and Engineering: Dissertations, Theses, and Student Research

The use of unmanned aerial vehicles (UAVs) in construction sites has been widely growing for surveying and inspection purposes. Their mobility and agility have enabled engineers to use UAVs in Structural Health Monitoring (SHM) applications to overcome the limitations of traditional approaches that require labor-intensive installation, extended time, and long-term maintenance. One of the critical applications of SHM is measuring bridge deflections during the bridge operation period. Due to the complex remote sites of bridges, remote sensing techniques, such as camera-equipped drones, can facilitate measuring bridge deflections. This work takes a step to build a pipeline using the state-of-the-art computer …


Sim-To-Real Reinforcement Learning Framework For Autonomous Aerial Leaf Sampling, Ashraful Islam May 2023

Sim-To-Real Reinforcement Learning Framework For Autonomous Aerial Leaf Sampling, Ashraful Islam

Department of Computer Science and Engineering: Dissertations, Theses, and Student Research

Using unmanned aerial systems (UAS) for leaf sampling is contributing to a better understanding of the influence of climate change on plant species, and the dynamics of forest ecology by studying hard-to-reach tree canopies. Currently, multiple skilled operators are required for UAS maneuvering and using the leaf sampling tool. This often limits sampling to only the canopy top or periphery. Sim-to-real reinforcement learning (RL) can be leveraged to tackle challenges in the autonomous operation of aerial leaf sampling in the changing environment of a tree canopy. However, trans- ferring an RL controller that is learned in simulation to real UAS …


Modeled Uranium Series Disequilibria In A Heterogeneous Mantle Underlying Iceland, Dana Andersen May 2023

Modeled Uranium Series Disequilibria In A Heterogeneous Mantle Underlying Iceland, Dana Andersen

Honors Theses

Regional lithologic heterogeneities in Earth’s mantle may significantly contribute to variations in magma productivity and crustal generation. Such heterogeneities may be a key factor in the anomalously high rates of magmatism and thickened crust of Iceland, which are not fully explained by the presence of a mantle plume. However, the exact lithologic composition of the mantle underlying Iceland is largely unknown. Recent trace element modeling has suggested a two-component melt source beneath Iceland, consisting of a typical upper mantle peridotite mixing with one of several compositions of pyroxenitic material. This study further investigates these potential melt sources by calculating U-series …


Theory Of Invariant Manifold And Foliation And Uniqueness Of Center Manifold Dynamics, Bo Deng Apr 2023

Theory Of Invariant Manifold And Foliation And Uniqueness Of Center Manifold Dynamics, Bo Deng

Department of Mathematics: Faculty Publications

Here we prove that the dynamics on any two center-manifolds of a fixed point of any Ck,1 dynamical system of finite dimension with k ≥ 1 are Ck-conjugate to each other. For pedagogical purpose, we also extend Perron’s method for differential equations to diffeomorphisms to construct the theory of invariant manifolds and invariant foliations at fixed points of dynamical systems of finite dimensions.


The Influence Of The Substrate On The Functionality Of Spin Crossover Molecular Materials, Saeed Yazdani, Jared Phillips, Thilini K. Ekanayaka, Ruihua Cheng, Peter A. Dowben Apr 2023

The Influence Of The Substrate On The Functionality Of Spin Crossover Molecular Materials, Saeed Yazdani, Jared Phillips, Thilini K. Ekanayaka, Ruihua Cheng, Peter A. Dowben

Department of Physics and Astronomy: Faculty Publications

Spin crossover complexes are a route toward designing molecular devices with a facile readout due to the change in conductance that accompanies the change in spin state. Because substrate effects are important for any molecular device, there are increased efforts to characterize the influence of the substrate on the spin state transition. Several classes of spin crossover molecules deposited on different types of surface, including metallic and non-metallic substrates, are comprehensively reviewed here. While some non-metallic substrates like graphite seem to be promising from experimental measurements, theoretical and experimental studies indicate that 2D semiconductor surfaces will have minimum interaction with …


Stabilizing Polar Phases In Binary Metal Oxides By Hole Doping, Tengfei Cao, Guodong Ren, Ding-Fu Shao, Evgeny Y. Tsymbal, Rohan Mishra Apr 2023

Stabilizing Polar Phases In Binary Metal Oxides By Hole Doping, Tengfei Cao, Guodong Ren, Ding-Fu Shao, Evgeny Y. Tsymbal, Rohan Mishra

Department of Physics and Astronomy: Faculty Publications

The recent observation of ferroelectricity in the metastable phases of binary metal oxides, such as HfO2, ZrO2, Hf0.5Zr0.5O2, and Ga2O3, has garnered a lot of attention. These metastable ferroelectric phases are typically stabilized using epitaxial strain, alloying, or defect engineering. Here, we propose that hole doping plays a key role in the stabilization of polar phases in binary metal oxides. Using first-principles density-functional-theory calculations, we show that holes in these oxides mainly occupy one of the two oxygen sublattices. This hole localization, which is more pronounced …


Climate-Controlled Submarine Landslides On The Antarctic Continental Margin, Jenny A. Gales, Robert M. Mckay, Laura De Santis, Michele Rebesco, Jan Sverre Laberg, Amelia E. Shevenell, David M. Harwood, R. Mark Leckie, Denise K. Kulhanek, Maxine King, Molly Patterson, Renata G. Lucchi, Sookwan Kim, Sunghan Kim, Justin Dodd, Julia Seidenstein, Catherine Prunella, Giulia M. Ferrante, Iodp Expedition Apr 2023

Climate-Controlled Submarine Landslides On The Antarctic Continental Margin, Jenny A. Gales, Robert M. Mckay, Laura De Santis, Michele Rebesco, Jan Sverre Laberg, Amelia E. Shevenell, David M. Harwood, R. Mark Leckie, Denise K. Kulhanek, Maxine King, Molly Patterson, Renata G. Lucchi, Sookwan Kim, Sunghan Kim, Justin Dodd, Julia Seidenstein, Catherine Prunella, Giulia M. Ferrante, Iodp Expedition

Department of Earth and Atmospheric Sciences: Faculty Publications

Antarctica’s continental margins pose an unknown submarine landslidegenerated tsunami risk to Southern Hemisphere populations and infrastructure. Understanding the factors driving slope failure is essential to assessing future geohazards. Here, we present a multidisciplinary study of a major submarine landslide complex along the eastern Ross Sea continental slope (Antarctica) that identifies preconditioning factors and failure mechanisms. Weak layers, identified beneath three submarine landslides, consist of distinct packages of interbedded Miocene- to Pliocene-age diatom oozes and glaciomarine diamicts. The observed lithological differences, which arise from glacial to interglacial variations in biological productivity, ice proximity, and ocean circulation, caused changes in sediment deposition …


Permian Trilobites And The Applicability Of The “Living Fossil” Concept To Extinct Clades, Melanie J. Hopkins, Peter Wagner, Katherine J. Jordan Apr 2023

Permian Trilobites And The Applicability Of The “Living Fossil” Concept To Extinct Clades, Melanie J. Hopkins, Peter Wagner, Katherine J. Jordan

Department of Earth and Atmospheric Sciences: Faculty Publications

Some taxa occupy our imaginations as “living fossils” because they were known from the fossil record before being discovered alive today. Other taxa are considered “living fossils” because modern relatives bear a strong morphological resemblance to fossil relatives, or because they occupy a contracted geographic range or have less diversity now than in the past, or because they represent phylogenetic diversity that requires conservation. A characterizing feature of living fossils–and thus an implicit assumption of all criteria–is that the “living fossil” of interest is extant. However, the general research questions that “living fossils” inspire–Why do rates of evolution vary across …


Science Club, Danielle Gibson, Krista Andersen Apr 2023

Science Club, Danielle Gibson, Krista Andersen

Honors Expanded Learning Clubs

Honors After School program for elementary age children to engage with scientific principles. Students performed hands-on experiments to explore various STEM fields. Each weekly lesson consisted of a different concept to be learned or explored by early elementary aged students.


How Resilience Is Framed Matters For Governance Of Coastal Social-Ecological Systems, Sarah Clement, Javad Jozaei, Michael Mitchell, Craig R. Allen, Ahjond S. Garmestani Apr 2023

How Resilience Is Framed Matters For Governance Of Coastal Social-Ecological Systems, Sarah Clement, Javad Jozaei, Michael Mitchell, Craig R. Allen, Ahjond S. Garmestani

School of Natural Resources: Faculty Publications

Effective governance of social-ecological systems (SES) is an enduring challenge, especially in coastal environments where accelerating impacts of climate change are increasing pressure on already stressed systems. While resilience is often proposed as a suitable framing to re-orient governance and management, the literature includes many different, and sometimes conflicting, definitions and ideas that influence how the concept is applied, especially in coastal environments. This study combines discourse analysis of the coastal governance literature and key informant interviews in Tasmania, Australia, demonstrating inconsistencies and confusion in the way that resilience is framed in coastal governance research and practice. We find that …


Towards A Global Sustainable Development Agenda Built On Social–Ecological Resilience, Murray W. Scown, Robin K. Craig, Craig R. Allen, Lance Gunderson, David G. Angeler, Jorge H. Garcia, Ahjond Garmestani Apr 2023

Towards A Global Sustainable Development Agenda Built On Social–Ecological Resilience, Murray W. Scown, Robin K. Craig, Craig R. Allen, Lance Gunderson, David G. Angeler, Jorge H. Garcia, Ahjond Garmestani

School of Natural Resources: Faculty Publications

Non-technical summary. The United Nations’ sustainable development goals (SDGs) articulate societal aspirations for people and our planet. Many scientists have criticised the SDGs and some have suggested that a better understanding of the complex interactions between society and the environment should underpin the next global development agenda. We further this discussion through the theory of social–ecological resilience, which emphasises the ability of systems to absorb, adapt, and transform in the face of change. We determine the strengths of the current SDGs, which should form a basis for the next agenda, and identify key gaps that should be filled.

Technical …


The Spin Polarization Of Palladium On Magneto-Electric Cr2O3, Takashi Komesu, Will Echtenkamp,, Christian H. Binek, Peter A. Dowben Apr 2023

The Spin Polarization Of Palladium On Magneto-Electric Cr2O3, Takashi Komesu, Will Echtenkamp,, Christian H. Binek, Peter A. Dowben

Department of Physics and Astronomy: Faculty Publications

While induced spin polarization of a palladium (Pd) overlayer on antiferromagnetic and magneto-electric Cr2O3(0001) is possible because of the boundary polarization at the Cr2O3(0001), in the single domain state, the Pd thin film appears to be ferromagnetic on its own, likely as a result of strain. In the conduction band, we find the experimental evidence of ferromagnetic spin polarized in Pd thin films on a Cr2O3(0001) single crystal, especially in the thin limit, Pd thickness of around 1–4 nm. Indeed there is significant spin polarization in 10 Å …


Deficit Irrigation Management For Irrigated Corn In Nebraska: Economically Viable?, Lia Nogueira, Cory Walters, Emily O'Donnell, Wesley Peterson, Suat Irmak Apr 2023

Deficit Irrigation Management For Irrigated Corn In Nebraska: Economically Viable?, Lia Nogueira, Cory Walters, Emily O'Donnell, Wesley Peterson, Suat Irmak

Cornhusker Economics

In this study we determine the economic value of deficit irrigation management using both technological and methodological advancements. The use of soil moisture probes represents the technological improvement. We provide improvements in the methodology as follows. Regarding data, we employ a field-size study, instead of plots, where the irrigation decision is determined by the moisture level in the soil measured through a soil moisture probe. Regarding the understanding of the yield response to water, although we examine the commonly used quadratic function, we improve upon this specification by also examining an alternative response function, the linear response stochastic plateau. Our …


Spot-Fire Distance Increases Disproportionately For Wildfires Compared To Prescribed Fires As Grasslands Transition To Juniperus Woodlands, Victoria M. Donovan, Dillon T. Fogarty, Dirac L. Twidwell Jr Apr 2023

Spot-Fire Distance Increases Disproportionately For Wildfires Compared To Prescribed Fires As Grasslands Transition To Juniperus Woodlands, Victoria M. Donovan, Dillon T. Fogarty, Dirac L. Twidwell Jr

School of Natural Resources: Faculty Publications

Woody encroachment is one of the greatest threats to grasslands globally, depleting a suite of ecosystem services, including forage production and grassland biodiversity. Recent evidence also suggests that woody encroachment increases wildfire danger, particularly in the Great Plains of North America, where highly volatile Juniperus spp. convert grasslands to an alternative woodland state. Spot-fire distances are a critical component of wildfire danger, describing the distance over which embers from one fire can cause a new fire ignition, potentially far away from fire suppression personnel. We assess changes in spot-fire distances as grasslands experience Juniperus encroachment to an alternative woodland state …


E6 Models In Light Of Precision MW Measurements, Vernon Barger, Cash Hauptmann, Peisi Huang, Wai-Yee Keung Apr 2023

E6 Models In Light Of Precision MW Measurements, Vernon Barger, Cash Hauptmann, Peisi Huang, Wai-Yee Keung

Department of Physics and Astronomy: Faculty Publications

We propose a solution to the recent W mass measurement by embedding the Standard Model within E6 models. The presence of a new U(1) group shifts the W boson mass at the tree level and introduces a new gauge boson Z' which has been searched for at collider experiments. In this article, we identify the parameter space that explains the new W mass measurement and is consistent with current experimental Z' searches. As U(1) extensions can be accommodated in supersymmetric models, we also consider the supersymmetric scenario of E6 models, and show that a 125 GeV …


Convolutional Neural Networks Analysis Reveals Three Possible Sources Of Bronze Age Writings Between Greece And India, Shruti Daggumati, Peter Z. Revesz Apr 2023

Convolutional Neural Networks Analysis Reveals Three Possible Sources Of Bronze Age Writings Between Greece And India, Shruti Daggumati, Peter Z. Revesz

School of Computing: Faculty Publications

This paper analyzes the relationships among eight ancient scripts from between Greece and India. We used convolutional neural networks combined with support vector machines to give a numerical rating of the similarity between pairs of signs (one sign from each of two different scripts). Two scripts that had a one-to-one matching of their signs were determined to be related. The result of the analysis is the finding of the following three groups, which are listed in chronological order: (1) Sumerian pictograms, the Indus Valley script, and the proto-Elamite script; (2) Cretan hieroglyphs and Linear B; and (3) the Phoenician, Greek, …


Test 2240: Kubota M8-231, Nebraska Tractor Test Lab Apr 2023

Test 2240: Kubota M8-231, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …


Nash Blowups Of Toric Varieties In Prime Characteristic, Daniel Duarte, Jack Jeffries, Luis Núñez-Betancourt Apr 2023

Nash Blowups Of Toric Varieties In Prime Characteristic, Daniel Duarte, Jack Jeffries, Luis Núñez-Betancourt

Department of Mathematics: Faculty Publications

We initiate the study of the resolution of singularities properties of Nash blowups over fields of prime characteristic. We prove that the iteration of normalized Nash blowups desingularizes normal toric surfaces. We also introduce a prime characteristic version of the logarithmic Jacobian ideal of a toric variety and prove that its blowup coincides with the Nash blowup of the variety. As a consequence, the Nash blowup of a, not necessarily normal, toric variety of arbitrary dimension in prime characteristic can be described combinatorially.


Test Beam Performance Of A Cbc3-Based Mini-Module For The Phase-2 Cms Outer Tracker Before And After Neutron Irradiation, Cms Collaboration Apr 2023

Test Beam Performance Of A Cbc3-Based Mini-Module For The Phase-2 Cms Outer Tracker Before And After Neutron Irradiation, Cms Collaboration

Department of Physics and Astronomy: Faculty Publications

The Large Hadron Collider (LHC) at CERN will undergo major upgrades to increase the instantaneous luminosity up to 5–7.5 × 1034 cm-2s-1. This High Luminosity upgrade of the LHC (HL-LHC) will deliver a total of 3000–4000 fb-1 of proton-proton collisions at a center-of-mass energy of 13–14 TeV. To cope with these challenging environmental conditions, the strip tracker of the CMS experiment will be upgraded using modules with two closely-spaced silicon sensors to provide information to include tracking in the Level-1 trigger selection. This paper describes the performance, in a test beam experiment, of the …


A Method To Measure Positron Beam Polarization Using Optically Polarized Atoms, Joshua Joshua Machacek, Sean Hodgman, Stephen Buckman, T. J. Gay Apr 2023

A Method To Measure Positron Beam Polarization Using Optically Polarized Atoms, Joshua Joshua Machacek, Sean Hodgman, Stephen Buckman, T. J. Gay

Department of Physics and Astronomy: Faculty Publications

We outline an experimental technique for measuring the degree of polarization of a positron beam using an optically pumped, spin-polarized Rb target. The technique is based on the production and measurement of the ortho- and para-positronium fractions through positron collisions with the Rb atoms as a function of their polarization. Using realistic estimates for the cross sections and experimental parameters involved, we estimate that a polarization measurement with an uncertainty of 3% of the measured value can be achieved in an hour


Water Current, Volume 55, No. 1, Spring 2023 Apr 2023

Water Current, Volume 55, No. 1, Spring 2023

Water Current Newsletter

No abstract provided.


Extremal Absorbing Sets In Low-Density Parity-Check Codes, Emily Mcmillon, Allison Beemer, Christine A. Kelley Apr 2023

Extremal Absorbing Sets In Low-Density Parity-Check Codes, Emily Mcmillon, Allison Beemer, Christine A. Kelley

Department of Mathematics: Faculty Publications

Absorbing sets are combinatorial structures in the Tanner graphs of low-density parity-check (LDPC) codes that have been shown to inhibit the high signal-to-noise ratio performance of iterative decoders over many communication channels. Absorbing sets of minimum size are the most likely to cause errors, and thus have been the focus of much research. In this paper, we determine the sizes of absorbing sets that can occur in general and left-regular LDPC code graphs, with emphasis on the range of b for a given a for which an (a, b)-absorbing set may exist. We identify certain cases of extremal …


Highly Pathogenic Avian Influenza A(H5n1) Virus Outbreak In New England Seals, United States, Wendy Puryear, Kaitlin Sawatzki, Nichola Hill, Alexa Foss, Jonathon J. Stone, Lynda Doughty, Dominique Walk, Katie Gilbert, Maureen Murray, Elena Cox, Priya Patel, Zak Mertz, Stephanie Ellis, Jennifer Taylor, Deborah Fauquier, Ainsley Smith, Robert A. Digiovanni, Adriana Van De Guchte, Ana Silvia Gonzalez-Reiche, Zain Khalil, Harm Van Bakel, Mia K. Torchetti, Kristina Lantz, Julianna B. Lenoch, Jonathan Runstadler Apr 2023

Highly Pathogenic Avian Influenza A(H5n1) Virus Outbreak In New England Seals, United States, Wendy Puryear, Kaitlin Sawatzki, Nichola Hill, Alexa Foss, Jonathon J. Stone, Lynda Doughty, Dominique Walk, Katie Gilbert, Maureen Murray, Elena Cox, Priya Patel, Zak Mertz, Stephanie Ellis, Jennifer Taylor, Deborah Fauquier, Ainsley Smith, Robert A. Digiovanni, Adriana Van De Guchte, Ana Silvia Gonzalez-Reiche, Zain Khalil, Harm Van Bakel, Mia K. Torchetti, Kristina Lantz, Julianna B. Lenoch, Jonathan Runstadler

United States Department of Agriculture Wildlife Services: Staff Publications

We report the spillover of highly pathogenic avian influenza A(H5N1) into marine mammals in the northeastern United States, coincident with H5N1 in sympatric wild birds. Our data indicate monitoring both wild coastal birds and marine mammals will be critical to determine pandemic potential of influenza A viruses.


Sustainability Club, Brianna Bernhardt, Marissa Lindemann Apr 2023

Sustainability Club, Brianna Bernhardt, Marissa Lindemann

Honors Expanded Learning Clubs

An environmental and agricultural-based club focusing on sustainability. Results in a cleaner school environment, knowledge about various sustainable practices, art projects, and an appreciation of nature.


Stem Club, Rohan Tatineni, Kevin Prososki Apr 2023

Stem Club, Rohan Tatineni, Kevin Prososki

Honors Expanded Learning Clubs

The goal of STEM club is to teach the students various basic scientific principles and relate them to experiments and the real world. In addition, the scientific method will be taught and be a main focus of the club along with the engineering design process.


Extraction And Analytical Method For N-Nitrosoatrazine Using Liquid Chromatography Paired With Tandem Mass Spectrometry, Carolyn Billings Apr 2023

Extraction And Analytical Method For N-Nitrosoatrazine Using Liquid Chromatography Paired With Tandem Mass Spectrometry, Carolyn Billings

Honors Theses

Atrazine is an herbicide used in the United States to control weeds. When combined with nitrite, atrazine can be nitrosated to form N-nitrosoatrazine (NNAT) in vivo and in vitro under acidic conditions. Atrazine can also be metabolized to atrazine mercapturate, deethylatrazine (DEA), didealkylatrazine (DDA), and deisopropylatrazine (DIA). Atrazine is monitored in drinking water due to its possible carcinogenicity. The objective of this study was to develop extraction and analytical methods for NNAT, atrazine, and atrazine metabolites. An instrument detection limit, extraction methods comparison, and extraction method detection limit were determined. To compare methods, Fischer 344 rat tissue samples were …