Physical Sciences and Mathematics Commons^™

Soil Contamination Due To Nuclear Testing, Animesh Jha

Natural Sciences Student Research Presentations

Why this topic:

• Nuclear contamination has long term effects (cdc.gov)
• Australia and the U.S. took land from indigenous peoples to conduct nuclear tests (Rapaport, Hughes)
• Give idea of whether indigenous peoples can return to their lands safely

Soil Health And The Effects Of Nanoparticles, Elijah Mock

Natural Sciences Student Research Presentations

I researched the effects of soil on human health. Specifically, I was interested in nanoparticles that reside in soil and how they affect humans as well as crops that are planted in the soil. This topic is relevant because nanoparticles can be used to deliver drugs for doctors, create specific properties for material scientists, sensors for the military, and in a plethora of other fields (“What Are Nanoparticles? Definition, Size, Uses and Properties.”).

Developing An Ios Game Application: Magnet Hockey, Trevor D. Wysong

The Graduate Review

Mobile application development requires mindful and meticulous planning. Application design should be responsive and intuitive so that navigation feels natural for the user. All targeted devices should be offered a relatively consistent experience. To ensure this, app performance needs to be closely monitored and different screen sizes and aspect ratios need to be considered when scaling. For an app to become attractive to many people, it should either be competitive with similar apps or be unique and interesting enough to entice people to download it. A unique app should couple familiar elements with new components or twists [8]. People are …

Branches: A University Of Maine Farmington Anthology Celebrating Work From Students Across The Arts & Humanities, Sciences, And Education, University Of Maine At Farmington, Gretchen Legler (Ed.), Joseph W. Mcdonnell

Student Books

Branches showcases student work from across the “disciplines” that make up the interconnected web of learning at a liberal arts university such as UMF. Reading through it, you’ll see what a vibrant intellectual and creative community we have created; all the branches of the tree of knowledge complement and inform one another, creating an organic whole that is truly more than the sum of its parts. This vision of an education has its roots in Classical Greece, where philosophers believed that knowledge gained through broad study across the arts, sciences, and philosophy was essential for creating free citizens who would …

Campus Mobile History Application, Drew Adan, Christine Sears

Summer Community of Scholars (RCEU and HCR) Project Proposals

No abstract provided.

Provenance Of The Northern Range, Trinidad Using Detrital Zircon U-Pb Geochronology: Implications For Northern South American River System Paleogeography, Cheyenne Bartelt

Geology: Student Scholarship & Creative Works

The Northern Range of Trinidad is located in a key area for evaluating the Mesozoic-Cenozoic evolution of the Caribbean and South American plates. Here, we present detrital zircon U-Pb geochronology for 2391 grains from ten samples collected from metasedimentary rocks of the Northern Range. These data are used to bracket the maximum depositional age of the fossil-poor metasedimentary rocks from the Northern Range and to investigate the provenance of their sedimentary protoliths. Detrital zircon ages range between 3136.5 ± 22.9 Ma and 139.0 ± 5.4 Ma, reflecting apparent contribution from a variety of crustal affinities; however, since the youngest ages …

The Beverton-Hold Model On Isolated Time Scales, Martin Bohner, Jaqueline Mesquita, Sabrina Streipert

Mathematics and Statistics Faculty Research & Creative Works

In this work, we formulate the Beverton-Holt model on isolated time scales and extend existing results known in the discrete and quantum calculus cases. Applying a recently introduced definition of periodicity for arbitrary isolated time scales, we discuss the effects of periodicity onto a population modeled by a dynamic version of the Beverton-Holt equation. The first main theorem provides conditions for the existence of a unique !-periodic solution that is globally asymptotically stable, which addresses the first Cushing-Henson conjecture on isolated time scales. The second main theorem concerns the generalization of the second Cushing-Henson conjecture. It investigates the effects of …

Optimal Equivalence Testing In Exponential Families, Renren Zhao, Robert L. Paige

Mathematics and Statistics Faculty Research & Creative Works

We develop uniformly most powerful unbiased (UMPU) two sample equivalence test for a difference of canonical parameters in exponential families. This development involves a non-unique reparameterization. We address this issue via a novel characterization of all possible reparameterizations of interest in terms of a matrix group. Furthermore, our procedure involves an intractable conditional distribution which we reproduce to a high degree of accuracy using saddle point approximations. The development of this saddle point-based procedure involves a non-unique reparameterization, but we show that our procedure is invariant under choice of reparameterization. Our real data example considers the mean-to-variance ratio for normally …

On The Hartogs Extension Theorem For Unbounded Domains In CN, Al Boggess, Roman Dwilewicz, Egmont Porten

Mathematics and Statistics Faculty Research & Creative Works

Let Ω ⊂ Cn, n > 2, be a domain with smooth connected boundary. If Ω is relatively compact, the Hartogs–Bochner theorem ensures that every CR distribution on ∂Ω has a holomorphic extension to Ω. For unbounded domains this extension property may fail, for example if Ω contains a complex hypersurface. The main result in this paper tells that the extension property holds if and only if the envelope of holomorphy of Cn \ Ω is Cn. It seems that it is the first result in the literature which gives a geometric characterization of unbounded domains in Cn for which the …

Fundamental Structure Of General Stochastic Dynamical Systems: High-Dimension Case, Haoyu Wang, Xiaoliang Gan, Wenqing Hu, Ping Ao

Mathematics and Statistics Faculty Research & Creative Works

No one has proved that mathematically general stochastic dynamical systems have a special structure. Thus, we introduce a structure of a general stochastic dynamical system. According to scientific understanding, we assert that its deterministic part can be decomposed into three significant parts: the gradient of the potential function, friction matrix and Lorenz matrix. Our previous work proved this structure for the low-dimension case. In this paper, we prove this structure for the high-dimension case. Hence, this structure of general stochastic dynamical systems is fundamental.

Testing Xrf Identification Of Marine Washover Sediment Beds In A Coastal Lake In Southeastern Texas, Usa, Harry F. L. Williams, Chelsea E. Beaubouef, Kam-Biu Liu, Nicholas Culligan, Lance Riedlinger

Faculty Publications

This study tests the ability of a novel approach to identifying washover beds in coastal lakes. Combined X-Ray Fluorescence (XRF) and cluster analysis was used to identify hurricane washover beds in sediment cores from Clam Lake on the McFaddin National Wildlife Refuge in southeastern Texas. The lake is known to contain washover beds from recent hurricanes, but the washover sediment has similar microfossil, loss-on-ignition and textural characteristics to non-washover sediment and is not readily distinguishable. Sediment cores taken from marshes surrounding the lake do contain visually-recognizable sandy washover beds of Hurricanes Ike, Rita, Carla and Audrey. XRF analysis of these …

Influence Of Bedrock Erodibility On Orogen Evolution In Collisional Systems And Implications For Geodynamic Models, Stephanie Ann Sparks

Theses and Dissertations--Earth and Environmental Sciences

Theoretical and numerical geodynamic models of continental collisional systems often involve, either explicitly or implicitly, a necessary yet complicated dependence between tectonics and erosion; however, the exact nature of these relationships remains elusive and controversial. In such models for the Himalayan-Tibetan (H-T) collisional orogen, surface processes are theorized or in some cases required to play an essential role in modulating critical processes active in the evolution of that system. To investigate, at least to first order. these interactions between climate and tectonics, we generate a simplified landscape evolution model of an actively uplifting orogenic wedge acted upon by surface processes. …

Syn- To Post-Orogenic Evolution Of Collisional Mountain Systems: Investigating The Potential For Crustal Flow Using Thermochronology And Numerical Models, Brandon Spencer

Theses and Dissertations--Earth and Environmental Sciences

This dissertation is composed of three distinct manuscripts which collectively investigate processes that contribute to the late evolution of collisional mountain systems —specifically, the ancient Appalachian-Caledonian system. In the first paper, ⁴⁰Ar/³⁹Ar thermochronological data are used to constrain the timing of exhumation of the Scandian orogenic wedge of northern Scotland. Muscovite and amphibole samples yield dates of ca. 420-411 Ma, consistent with cooling after peak orogenesis. During this cooling phase, dates from both systems in individual thrust sheets show an increase in cooling rate in the later stage of exhumation; in the orogenic core, the cooling rate …

Experiment 1.02: Acceleration Due To Gravity: Vertical Drop, Diego Castano

Physics Lab Experiments with Simulated Data for Remote Delivery

The acceleration due to gravity is determined from the fall of a metal sphere.

Experiment 1.04: Newton's 2nd Law, Diego Castano

Physics Lab Experiments with Simulated Data for Remote Delivery

The motion of a modified Atwood-type machine is studied.

Experiment 1.07: Torque, Diego Castano

Physics Lab Experiments with Simulated Data for Remote Delivery

A mechanical balance is used to study the role of torque in states of static equilibrium.

Experiment 1.08: Buoyancy, Diego Castano

Physics Lab Experiments with Simulated Data for Remote Delivery

Archimedes Principle is used to determine the density of an unknown metal.

Experiment 1.05: Energy, Diego Castano, Victor Castro

Physics Lab Experiments with Simulated Data for Remote Delivery

The conservation of energy for the case of a descending glider on an inclined air-track is examined.

Experiment 1.06: Momentum, Diego Castano, Andrew Kiene

Physics Lab Experiments with Simulated Data for Remote Delivery

The conservation of momentum for the case of colliding gliders on an air-track is examined.

Experiment 1.03: Acceleration Due To Gravity: Inclined Surface, Diego Castano

Physics Lab Experiments with Simulated Data for Remote Delivery

The acceleration due to gravity is determined from the descent of a near frictionless glider on an inclined air-track.

Experiment 1.01: Measurement, Diego Castano, Victor Castro

Physics Lab Experiments with Simulated Data for Remote Delivery

Introduction to measurement/data analysis; measurements of an aluminum cylinder and cuboid are used to determine their densities.

Experiment 1.10: Standing Waves On Strings, Diego Castano

Physics Lab Experiments with Simulated Data for Remote Delivery

The fourth harmonic of a vibrating string is used to determine the acceleration due to gravity.

Experiment 1.09: The Simple Pendulum, Diego Castano

Physics Lab Experiments with Simulated Data for Remote Delivery

A simple pendulum is used to determine the acceleration due to gravity.

A Greenhouse Gas Emissions Inventory For Nebraska: Livestock And Coal Loom Large, Eric R. Holley, Adam Liska

Adam Liska Papers

Mitigation of climate change requires the systematic identification and cataloging of emissions sources at city, state, and national levels. In this study, an inventory of annual greenhouse gas emissions from the state of Nebraska was created based on industry data, and emissions inventories were completed each year from 1990 to 2016. Nebraska’s net emissions were found to increase from 56.2 million metric tons of carbon dioxide equivalents (MMtCO₂e) in 1990 to 87.4 MMtCO₂e in 2016. Agriculture was found to be the sector with the most emissions (36 MMtCO₂e) followed by electricity generation (21 MMtCO …

Tunneling Magnetoresistance In Noncollinear Antiferromagnetic Tunnel Junctions, J. Dong, X. Li, G. Gurung, M. Zhu, P. Zhang, F. Zheng, E. Y. Tsymbal, J. Zhang

Evgeny Tsymbal Publications

Antiferromagnetic (AFM) spintronics has emerged as a subfield of spintronics driven by the advantages of antiferromagnets producing no stray fields and exhibiting ultrafast magnetization dynamics. The efficient method to detect an AFM order parameter, known as the Néel vector, by electric means is critical to realize concepts of AFM spintronics. Here, we demonstrate that noncollinear AFM metals, such as Mn₃Sn, exhibit a momentum dependent spin polarization which can be exploited in AFM tunnel junctions to detect the Néel vector. Using first-principles calculations, we predict a tunneling magnetoresistance (TMR) effect as high as 300% in AFM tunnel junctions with …

Tilted Spin Current Generated By The Collinear Antiferromagnet Ruo2, A. Bose, N. J. Schreiber, R. Jain, D.-F. Shao, H. P. Nair, J. Sun, X. S. Zhang, D. A. Muller, D. A. Muller, E. Y. Tsymbal, D. G. Schlom, D. C. Ralph

Evgeny Tsymbal Publications

No abstract provided.

Direct Observation Of Ferroelectric Switching In Two-Dimensional Mos2, A. Lipatov, P. Chaudhary, Z. Guan, H. Lu, G. Li, O. Crégut, K. D. Dorkenoo, R. Proksch, D.-F. Shao, E. Y. Tsymbal, J. Íñiguez, A. Sinitskii, A. Gruverman

Evgeny Tsymbal Publications

No abstract provided.

Ferroelectric Control Of Magnetic Skyrmions In Two-Dimensional Van Der Waals Heterostructures, K. Huang, D.-F. Shao, E. Y. Tsymbal

Evgeny Tsymbal Publications

No abstract provided.

Electronic Reconstruction At The Polar (111)-Oriented Oxide Interface, S. Ryu, H. Zhou, T. R. Paudel, N. Campbell, J. Podkaminer, C. W. Bark, T. Hernandez, D. D. Fong, Y. Zhang, L. Xie, X. Q. Pan, E. Y. Tsymbal, M. S. Rzchowski, And C. B. Eom

Evgeny Tsymbal Publications

No abstract provided.

An Assessment Of Geographic And Taxonomic Biases In Research On Climate Change-Related Range Shifts, Evan J. Parker

Library Map Prize

Geographic and taxonomic biases in ecological literature inhibit the ability of research to be generalized or translated to other systems. This is particularly true with research on climate change-related range shifts, where a diverse and representative set of observations is needed to understand the significant heterogeneity of range shifts and improve models. A literature review was conducted and biases were assessed by examining the geographic location of study areas, the taxonomic makeup of study species, and the location of study areas within species ranges. A substantial geographic skew towards terrestrial, mid-latitude North America and Europe was observed. However, taxonomic coverage …