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Full-Text Articles in Physical Sciences and Mathematics

Metal Semiconductor Contact Between Gold And Boron Carbide, Ethiyal Raj Wilson, Elena Echeverria, Aiyun Liu, Bin Dong, George Peterson, Michael Nastasi, Peter A. Dowben Aug 2016

Metal Semiconductor Contact Between Gold And Boron Carbide, Ethiyal Raj Wilson, Elena Echeverria, Aiyun Liu, Bin Dong, George Peterson, Michael Nastasi, Peter A. Dowben

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We have investigated the interaction of gold (Au) with the semiconductor boron carbide through X-ray photoemission and heterojunction diode fabrication. The plasma enhanced chemical vapor deposition (PECVD) hydrogenated semiconducting boron carbide films, deposited from closo-1,7-dicarbadodecaborane (metacarborane, m-B10C2H12), shows a shift in the binding energies of the core level photoemission features when gold is deposited on the surface. The shifting of the B 1s level is smaller than for the C 1s level and the non-uniform nature of the shifts indicates a strong, complex and reversible gold chemical interaction with the surface, particularly with the …


Simulation Of Relativistic Electrons Through A Magnetic Chicane, Matthias Fuchs, John Chrostek, Nathan W. Ray, Jordan O'Neal Aug 2016

Simulation Of Relativistic Electrons Through A Magnetic Chicane, Matthias Fuchs, John Chrostek, Nathan W. Ray, Jordan O'Neal

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Poster describing the path length differences for two relativistic electrons going through a series of four dipoles. This preliminary work will lead to full simulation of electron beam being compressed for use in an X-Ray Free Electron Laser in conjunction with magnetic quadruple lenses to create a small electron beam.


Variations In Satellite Derived Sea Ice And Snow Coverage In The Arctic, Haylie N. Mikulak Jul 2016

Variations In Satellite Derived Sea Ice And Snow Coverage In The Arctic, Haylie N. Mikulak

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The work is an investigation on the variations of satellite derived sea ice and snow cover extents in the Arctic region from 1979-2012. The NASA Making Earth System Data Records for Use in Research Environments (MEaSUREs) Hemisphere Snow and Ice Earth System Data Record is examined in order to find variations of Northern Hemispheric sea ice and snow cover extents and impacts each extent may have not only on one another as well as the changing atmospheric conditions over the study period. Extent patterns and extreme circumstances defined by this study are identified in order for future studies to examine …


The Effect Of Soil Ph On The Integument Of Western Tiger Salamanders, Aaron Devine, Dennis M. Ferraro May 2016

The Effect Of Soil Ph On The Integument Of Western Tiger Salamanders, Aaron Devine, Dennis M. Ferraro

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This study was done in an effort to better understand the multifaceted issues in amphibian decline, specifically within the eastern regions of Nebraska, to determine whether or not human-induced acid rain contributed to the decline. This is a heavily important topic of research as amphibians worldwide are declining related to many issues that stem from climate change and several other environmental issues of that nature. This study looked to use acidic pH within soil from western Nebraska to determine the reactionary impacts (primarily lesions) the western tiger salamander had after being subjected to it. It was found that pH did …


Chipathlon: A Competitive Assessment For Gene Regulation Tools., Avi Knecht, Adam Caprez, Istvan Ladunga Apr 2016

Chipathlon: A Competitive Assessment For Gene Regulation Tools., Avi Knecht, Adam Caprez, Istvan Ladunga

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When gene regulation of the cell cycle malfunctions, it frequently causes cancer.

Adult, differentiated cells can be reprogrammed to induced pluripotent stem cell; which can then be reprogrammed to heart muscle, skin, etc, to repair damaged tissue (to limited extent in clinical practice).

ChIPathlon: Evaluate the performance of all transcription factor mapping (peak calling) methods. To this end, we will develop a scalable and easy to use super computing pipeline to stage data, compare many different peak calling and differential binding site tools, and store all results into a single database.


Conjugacy Geodesics In Coxeter Groups, Aaron Calderon Apr 2016

Conjugacy Geodesics In Coxeter Groups, Aaron Calderon

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Take a square and flip it over the vertical axis, rotate it 90 degrees counterclockwise and then flip it again over the vertical axis. This sequence is the same as a 90 degree clockwise rotation but takes more steps to demonstrate the same symmetry. In general, the question of when a sequence of symmetries has minimal length is hard to answer and is dependent on the chosen generating set (in our toy example, rotation by 90 degrees and reflection). By realizing sequences of symmetries as paths in a group's Cayley graph, the problem becomes one about the set of shortest …


The Measure Of Nematode Diversity In Response To Varying Management Practices And Features In Restored And Remnant Prairie Ecosystems, Heaven A. Hulshizer Apr 2016

The Measure Of Nematode Diversity In Response To Varying Management Practices And Features In Restored And Remnant Prairie Ecosystems, Heaven A. Hulshizer

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"Tallgrass prairies are the most endangered ecosystem in North America” (Helen et al 2013). “Surveys suggest that since European settlement, declines in area of native prairie range as high as 99.9%”(Sampson, Fred and Fritz Knopf 1994). Prairie ecosystem services are abundant and range from mitigating floods to promoting biodiversity. (USDA Forest Service).Given these benefits, restoring prairies and maintaining native areas should be an important conservation priority. Nematodes, the most abundant animal species on earth, have been used as bio-indicators of soil quality (Neher; Todd). To better understand the dynamics of nematode diversity in native and restored prairies we examines whether …


A New Ligation System For Protein Conjugation, Alicia J. Curti, Patrick H. Dussault Apr 2016

A New Ligation System For Protein Conjugation, Alicia J. Curti, Patrick H. Dussault

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Click chemistry describes crosslinking reactions in which pairs of functional groups selectively “click” together to form linkages. The idea of our project is to explore the use of cyclobutene-containing fatty acids as a new class of “click” reagents as a tool for protein modification.

There is great interest in performing click reactions under biologically relevant conditions, in the presence of cells, and even within cells. The best known click reaction, the cycloaddition of alkynes and azides, is highly specific, can be conducted in the presence of buffers and proteins, and forms stable cycloadducts. However, use in biological systems is limited …


Flying By Fire: Making Controlled Burns Safer For Humans And Uavs, Rebecca Horzewski, Carrick Detweiler Apr 2016

Flying By Fire: Making Controlled Burns Safer For Humans And Uavs, Rebecca Horzewski, Carrick Detweiler

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A temperature sensing circuit board was developed that will allow Nimbus Lab's controlled burn starting UAV to react to the temperatures around it.


Alignment For Comprehensive Two-Dimensional Gas Chromatography (Gcxgc) With Global, Low-Order Polynomial Transformations, Davis Rempe, Stephen Reichenbach, Stephen Scott Apr 2016

Alignment For Comprehensive Two-Dimensional Gas Chromatography (Gcxgc) With Global, Low-Order Polynomial Transformations, Davis Rempe, Stephen Reichenbach, Stephen Scott

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As columns age and differ between systems, retention times for GC x GC may vary between runs. In order to properly analyze chromatograms, it is often desirable to align chromatographic features between chromatograms. This alignment can be characterized by a mapping of retention times from one chromatogram to the retention times of another chromatogram. Alignment methods can be classified as global or local, i.e., whether the geometric differences between chromatograms are characterized by a single function for the entire chromatogram or by a combination of many functions for different regions of the chromatogram. Previous work has shown that global, low-degree …


The History And Applications Of Fibonacci Numbers, Cashous W. Bortner, Allan C. Peterson Apr 2016

The History And Applications Of Fibonacci Numbers, Cashous W. Bortner, Allan C. Peterson

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The Fibonacci sequence is arguably the most observed sequence not only in mathematics, but also in nature. As we begin to learn more and more about the Fibonacci sequence and the numbers that make the sequence, many new and interesting applications of the have risen from different areas of algebra to market trading strategies. This poster analyzes not only the history of Leonardo Bonacci, but also the elegant sequence that is now his namesake and its appearance in nature as well as some of its current mathematical and non-mathematical applications.


Modeling The Movement Of Solutes Through The Subsurface: Application To Groundwater Remediation With Oxidant Candles, Colin Chatterton Apr 2016

Modeling The Movement Of Solutes Through The Subsurface: Application To Groundwater Remediation With Oxidant Candles, Colin Chatterton

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Groundwater remediation is a process that is heavily dependent upon the properties of the subsurface. Dispersion is a huge factor that controls the spread of a chemical’s mass from its center, which directly controls the volume of subsurface material affected (Pepper, Gerba, & Brusseau, 2006). Quantifying the dispersivity of the medium in the flow tank will help immensely in trying to accurately predict the zone of influence of the slow-release oxidant candles.


Fabrication And Characterization Of Layered Transition Metal Dichalcogenides, Peter Kosch, Zhiyong Xiao, Xia Hong Apr 2016

Fabrication And Characterization Of Layered Transition Metal Dichalcogenides, Peter Kosch, Zhiyong Xiao, Xia Hong

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The goal of my research was to mechanically exfoliate single to few atomic layer samples of Molybdenum Disulfide (MoS2 ), Tungsten Diselenide (WSe2 ), and Tungsten Disulfide (WS2 ) and characterize these 2D materials by multiple methods. I used Atomic Force Microscopy, Raman Spectroscopy, and Optical Microscopy to accomplish this. In addition, I measured the electrical properties of the exfoliated materials by fabricating a device and taking basic measurements.


Polarimetric Radar Signatures Of Supercell Thunderstorms In Tropical Cyclones, Emily Paltz, Matthew Van Den Broeke Apr 2016

Polarimetric Radar Signatures Of Supercell Thunderstorms In Tropical Cyclones, Emily Paltz, Matthew Van Den Broeke

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Background It is necessary for operational meteorologists to forecast quickly and accurately when storms have the potential of producing severe weather such as tornadoes or hail. Presently, radar represents the most effective way to monitor storms in real time. The National Weather Service recently upgraded the national radar network to polarimetric capability. Much time and resources have been devoted to understanding the development of Great Plains supercells such that polarimetric radar schematics have been developed for them. Little, however, has been done for tropical cyclone supercells. In this study we wish to determine typical polarimetric radar structure for supercells in …


Past Meets Future: Combining Gis, 3d Technologies, And Legacy Data To Reanalyze Ceramics At Copan, Honduras, Stephanie Sterling, Heather Richards-Rissetto, René Viel Apr 2016

Past Meets Future: Combining Gis, 3d Technologies, And Legacy Data To Reanalyze Ceramics At Copan, Honduras, Stephanie Sterling, Heather Richards-Rissetto, René Viel

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The archaeological site of Copán—a UNESCO World Heritage Site in Honduras—was a primary center for cultural and economic exchange in the Maya world from the fifth to ninth centuries. Our research investigates the sociopolitical climate of the city immediately preceding this collapse. This poster presents the results of a pilot study intended to evaluate the potential of using a combination of digital technologies and legacy data to reanalyze a subset of diagnostic ceramics from select sites outside of Copan’s urban core. Our methods involved:

(1) Applying photogrammetry to generate 3D models for approximately 30 potentially temporally-diagnostic ceramic types

(2) Digitizing, …


Determining The Age Of A Stabilized Dune Field, Carissa Raymond Apr 2016

Determining The Age Of A Stabilized Dune Field, Carissa Raymond

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The aim of this project was to assess the development and age of the Kearney Dunefield in central Nebraska through the collection and analysis of sand samples from the inactive dunes. These dunes are not part of the well-known Nebraska Sandhills, and so far have not been thoroughly studied. Similar assessments have been conducted on dune fields throughout the Great Plains, and this study seeks to place the Kearney Dunes into a regional context.

The OSL ages for the Kearney cores fall between approximately 590 and 690 years ago. These dates overlap with a period of activation for the Nebraska …


Iron Concretions In The Cretaceous Dakota Formation, Anthony Kohtz, Richard Kettler, David Loope Apr 2016

Iron Concretions In The Cretaceous Dakota Formation, Anthony Kohtz, Richard Kettler, David Loope

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The Cretaceous Dakota Formation contains abundant iron oxide concretions. The precursors to the iron concretions are siderite (FeCO3) nodules that formed in a reducing floodplain environment. A variety of concretion morphologies formed when the precursor siderite nodules were dissolved by oxidizing groundwater in a paleoaquifer. Iron-oxidizing bacteria are able to oxidize aqueous Fe(II) to Fe(III) oxy-hydroxide at microaerophilic and neutrophilic conditions. This study investigated these concretions to determine if there was a microbial element in their formation and to characterize the concretion morphologies present in the Dakota. This is important for complete paleoenvironment interpretations and astrobiology pursuits.


Iron Mobility In Desert Sandstone Aquifers: The Possible Role Of Siderite, Lubna Al Azri, David Loope Apr 2016

Iron Mobility In Desert Sandstone Aquifers: The Possible Role Of Siderite, Lubna Al Azri, David Loope

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Jordanians and a large number of refugees are drinking radiumcontaminated water from a sandstone aquifer. The problem is that this water passed through sandstone of the Disi Formation only after carbon dioxide and methane had bleached the sandstone, dissolving the Iron-oxide coatings and liberating heavy metals and radionuclides . The Iron that once coated the grains migrated to form Iron bands in the lower Um Ishrin Formation.

The major practical significance of this study involves water quality. The movement of Iron sandstone aquifers can drastically change groundwater chemistry; understanding how and when this movement takes place will help in locating …


Manipulation Of Beams Of Ultra-Relativistic Electrons To Create Femtosecond X-Ray Pulses, Jordan T. O'Neal, Austin Schulte, Rafal Rakowski, Matthias Fuchs Apr 2016

Manipulation Of Beams Of Ultra-Relativistic Electrons To Create Femtosecond X-Ray Pulses, Jordan T. O'Neal, Austin Schulte, Rafal Rakowski, Matthias Fuchs

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The research proposed here is expected to result in a crucial component used in a next-generation X-ray source. Typical conventional high-brightness X-ray sources (so-called synchrotron lightsources) are up to 30 football fields in size. Our group uses a novel technique based on ultrahigh-power lasers to develop a similar source that can readily fit into a single, university-scale laboratory. More specifically, the research conducted within this proposal will be concerned with the manipulation of beams of ultra-relativistic electrons, (electrons that move with almost the speed of light) with the goal to focus the particles into an area that is smaller than …


Viability Of The Use Of Electromagnetic Induction To Predict Streambed Properties, Alexandra R. Hruby Jan 2016

Viability Of The Use Of Electromagnetic Induction To Predict Streambed Properties, Alexandra R. Hruby

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This study examined whether electromagnetic induction is a reliable tool to predict various streambed properties, including water conductivity, water temperature, and hydraulic conductivity. The test site was along the North Loup River, outside of St. Paul, Nebraska. Electromagnetic induction was performed using a field portable, multi-frequency EMI tool. Hydraulic conductivity was measured using the falling-head permeameter test, and water temperature and conductivity were measured using handheld meters. The study found that there is a strong positive correlation between water conductivity and apparent electrical conductivity measured by electromagnetic induction. This relationship can be explored further through the analysis of spatial patterns …


Characterizing Crop Photomultiplier Tube Behavior At 1000 Volts, Zachary T. Smith Jan 2016

Characterizing Crop Photomultiplier Tube Behavior At 1000 Volts, Zachary T. Smith

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In an effort to prolong the lifetime of their Photomultiplier tubes (PMTs), the Cosmic Ray Observatory Project (CROP) made the decision to begin operating the PMTs at an operating voltage of 1000 Volts. The aim of this project was to characterize the fundamental behavior of the PMTs at this operating voltage using several tests. These tests include determining the optimal threshold level of the PMTs, the PMT efficiency, and the time stability of the PMT's output.