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Full-Text Articles in Physical Sciences and Mathematics

Integrated Geophysical Analysis Over Bathymetrists Seamounts And The Sierra Leone Rise, Alexa Fernandez Jul 2021

Integrated Geophysical Analysis Over Bathymetrists Seamounts And The Sierra Leone Rise, Alexa Fernandez

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The Bathymetrists Seamounts (BSM) are located northeast of the Sierra Leone Rise in the Atlantic Ocean. The northern seamounts have a southwest to northeast trend which is contrary to the current eastward motion of the African tectonic plate where they reside. The geological history and crustal structures of these features are poorly understood. The goal of this study is to integrate multiple geophysical data to better understand the crustal architecture and tectonic history of the BSM.

The seismic refraction study from Jones et al. (2015) was used as the baseline for isostatic modeling. This dataset suggested the presence of magmatic …


Nonlocal Helmholtz Decompositions And Connections To Classical Counterparts, Andrew Haar, Petronela Radu May 2020

Nonlocal Helmholtz Decompositions And Connections To Classical Counterparts, Andrew Haar, Petronela Radu

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In recent years nonlocal models have been successfully introduced in a variety of applications, such as dynamic fracture, nonlocal diffusion, flocking, and image processing. Thus, the development of a nonlocal calculus theory, together with the study of nonlocal operators has become the focus of many theoretical investigations. Our work focuses on a Helmholtz decomposition in the nonlocal (integral) framework. In the classical (differential) setting the Helmholtz decomposition states that we can decompose a three dimensional vector field as a sum of an irrotational function and a solenoidal function. We will define new nonlocal gradient and curl operators that allow us …


Remediation Strategies To Reduce Heavy Metal Uptake In Lettuce Grown In Contaminated Urban Soil, Ryley Thomas Apr 2020

Remediation Strategies To Reduce Heavy Metal Uptake In Lettuce Grown In Contaminated Urban Soil, Ryley Thomas

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Urban soils are increasingly used to produce food for local consumption, which requires at the same time management strategies that prevent the plant uptake of potentially present contaminants. This study was conducted to test different soil amendments for their ability to retain lead (Pb) and arsenic (As) within the soil matrix. The analyzed soil was taken from a potential community garden lot near a railroad in Lincoln, NE where elevated concentrations in Pb and As had been detected. Ponderosa pine biochar and spent coffee grounds were used as soil additives because of their documented chemical reactivity towards soil cations or …


Measurements Of Radio Pulse Reception With Stations Of The Ara Experiment Based On The Spicecore Pulser Data Set, Jesse Osborn, Ilya Kravchenko Dr. Apr 2020

Measurements Of Radio Pulse Reception With Stations Of The Ara Experiment Based On The Spicecore Pulser Data Set, Jesse Osborn, Ilya Kravchenko Dr.

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The Askaryan Radio Array Experiment located near the South Pole works to pinpoint specific instances of neutrinos from outside the solar system interacting with nucleons inside the Antarctic ice. Neutrinos are a subatomic particle that has nearly no mass and a net neutral charge. As they are, neutrinos tend not to interact with anything as they travel through space which means they can provide us with information about events occurring far from Earth that might not be easily attained through other methods. Neutrinos are known to be emitted from a myriad of sources, including the Sun, the interaction between cosmic …


Testing A Drone-Based Magnetic Field Surveying System, Erik Jacobson, Irina Filina Apr 2020

Testing A Drone-Based Magnetic Field Surveying System, Erik Jacobson, Irina Filina

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Aeromagnetic surveys are conducted by geoscientists to study subsurface geologic structures, such as faults. This type of survey uses a magnetometer mounted upon an airborne vehicle to collect magnetic field data. Magnetic anomalies are caused by variations in subsurface geology, namely in magnetic properties of subsurface rocks. Jacobson and Filina (2019) reported on the development of a new low cost drone, based magnetic field surveying system by the UNL Geophysics Team. This drone-based magnetic system is capable of collecting high resolution data at low speeds and low altitudes. The current study focuses on testing this system by conducting two flights …


Phosphorus Nmr And Its Application To Metabolomics, Paula Evans, Fatema Bhinderwala, Robert Powers, Martha Morton, Thomas Smith Apr 2020

Phosphorus Nmr And Its Application To Metabolomics, Paula Evans, Fatema Bhinderwala, Robert Powers, Martha Morton, Thomas Smith

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Stable isotopes are routinely employed by NMR metabolomics to highlight specific metabolic processes and to monitor pathway flux. 13C-carbon and 15N-nitrogen labeled nutrients are convenient sources of isotope tracers and are commonly added as supplements to a variety of biological systems ranging from cell cultures to animal models. Unlike 13C and 15N, 31P-phosphourous is a naturally abundant and NMR active isotope that doesn’t require an external supplemental source. To date, 31P NMR has seen limited usage in metabolomics because of a lack of reference spectra, difficulties in sample preparation, and an absence of two-dimensional (2D) NMR experiments. But, 31P NMR …


Management Effects On Soil Quality Of The Geary Soil Series In Thayer County, Nebraska, Aime Nishimwe Apr 2020

Management Effects On Soil Quality Of The Geary Soil Series In Thayer County, Nebraska, Aime Nishimwe

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The CGIAR reports that around 40% of global crop yield variability is explained by climate. While global food consumption is expected to soar in 2050, the impact of climate change accounts for approximately 5% decrease in crop productivity. FAO estimates a 60% increase in global food demand by 2050, with global population reaching 9.8 billions. Sustainable soil management was also noted to boost agricultural food production by 58%. The evaluation of the impact of different management practices on dynamic soil properties was conducted on Geary silty clay loam, 3 to 7 %, eroded soils, which are mainly used for crop …


Impacts Of Human Recreation On Nutrient Availability And Periphyton Abundance On The Niobrara River, Matthew Chen, Jessica Corman, Sydney Kimnach, Kayla Vondracek Apr 2020

Impacts Of Human Recreation On Nutrient Availability And Periphyton Abundance On The Niobrara River, Matthew Chen, Jessica Corman, Sydney Kimnach, Kayla Vondracek

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In freshwater ecosystems, eutrophication can create many problems. Excess nutrients, like nitrogen or phosphorus, promote algal or cyanobacterial growth. This growth also leads to increased organic matter production and decomposition, a process that can reduce oxygen concentration in the water. When this happens, species diversity declines, transparency of the water declines, and anoxia may lead to fish kills . Of particular concern is the possibility of cyanobacteria blooms that create compounds toxic for humans. Many of the waters across Nebraska receive excessive nutrients from human activities, largely related to agriculture (Dickey 1982). However, there is one river, the Niobrara River, …


Modeling Predator-Prey Interaction In A Two Patch System, Marc Wade Apr 2020

Modeling Predator-Prey Interaction In A Two Patch System, Marc Wade

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In this study we examine predator-prey relationships in the context of a two patch system. What is meant by a two patch system is that prey live in a habitat that consists of type 1 patches with an abundance of food and type 2 patches with no food. In our study, we will be assuming that predators cannot enter the first type of patch. We combine three well-established ecological theories: migration theory, optimal foraging theory, and the standard predator-prey model in order to answer the motivating question: "Under what environmental conditions is a predator population stable when predation can only …


Using Electrocoagulation To Remove Perfluoroalkyl And Polyfluoroalkyl Substances (Pfas) From Contaminated Water, Amy Yanagida Apr 2020

Using Electrocoagulation To Remove Perfluoroalkyl And Polyfluoroalkyl Substances (Pfas) From Contaminated Water, Amy Yanagida

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Perfluoroalkyl and Polyfluoroalkyl substances (PFAS) are a family of manmade chemicals that are used to improve the quality of several commercial products by making them resistant to heat, oil, stains, grease and water. Unfortunately, the chemical properties that make PFAS useful from an industrial perspective also make them mobile and recalcitrant once released into the environment. We used electrocoagulation to run a direct current through contaminated water to generate a zinc floc to precipiate PFAS out of water.


Transect Survey Biases And Correction Methods In Southern Africa, Erika Swenson, Larkin Powell Apr 2020

Transect Survey Biases And Correction Methods In Southern Africa, Erika Swenson, Larkin Powell

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In southern Africa, transect surveys and distance-based analyses are often used to obtain density and population estimates for species in large reserves or management zones. However, these estimates may be biased by unnaturally large concentrations of animals at waterholes that are on or near the path of the transect. We used empirical survey data from the Namibrand Nature Reserve in southwest Namibia to parameterize spatial simulations in which we distributed gemsbok (Oryx gazella) on a grid along a 50-kilometer transect. We created multiple simulations with and without waterholes to determine how the proportion of animals clumped at the …


Crystallization At Droplet Interfaces For The Fabrication Of Geometrically Programmed Synthetic Magnetosomes, Matthew Gromowsky, Michael Stoller, Maddee Rauhauser, Marcus Judah, Abhiteja Konda, Christopher Jurich, Stephen Morin Apr 2020

Crystallization At Droplet Interfaces For The Fabrication Of Geometrically Programmed Synthetic Magnetosomes, Matthew Gromowsky, Michael Stoller, Maddee Rauhauser, Marcus Judah, Abhiteja Konda, Christopher Jurich, Stephen Morin

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Many organisms rely on the precise growth, assembly, and/or organization of inorganic crystals to achieve vital functions, for example, three-dimensional structural support (i.e., skeletal systems based on calcite) or environmental sensing (i.e., magnetosomes based on magnetite). Mimicking the production of the complex products observed in these biomineralization processes, synthetically, remains challenging. Herein, a method for the synthesis of artificial magnetosomes with programmable magnetic domains was developed. Specifically, precursors were compartmentalized inside different surfactant-stabilized aqueous-phase droplets suspended in oil and microfluidic technologies were implemented to control their interactions precisely. When reactive droplets were brought into contact with one another, a lipid …


Explainable Deep Learning For Medical Image Analysis, Brennan Rhoadarmer Apr 2020

Explainable Deep Learning For Medical Image Analysis, Brennan Rhoadarmer

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Explainable Deep Learning for Medical Image Analysis is a project focused on improving the ability for deep learning models to explain the reasoning behind their classification in order to improve their viability in the medical field, where explanations of decisions is critical for the care of patients. In order to explore this topic, we work to implement GradCAM, which is a new method of determining the cause classification in models by tracing back through the model layers to the input.


Optimization Of Magnetic Chicane For Maximum Electron Beam Compression, Nathan W. Ray, Vida-Michelle Nixon, Matthias Fuchs Apr 2018

Optimization Of Magnetic Chicane For Maximum Electron Beam Compression, Nathan W. Ray, Vida-Michelle Nixon, Matthias Fuchs

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Research concerned with optimizing a negatively chirped, relativistic, short electron beam using General Particle Tracer (GPT). The GPT simulations have the ability to include realistic beam effects such as space charge, fringe fields and emittance. A series of electron beam energy spreads were simulated through several different iterations of dipole magnets and, utilizing GPT's optimization ability, the most consistent set of parameters was selected and displayed on the poster. With our presented iteration of parameters we noted a 89.5% compression of the electron beam along the propagating axis.


Impact Of Past Experiences With Tornadoes On Future Decisions In Nebraska, Emily Paltz, Michael Hayes, Matthew Van Den Broeke Jan 2018

Impact Of Past Experiences With Tornadoes On Future Decisions In Nebraska, Emily Paltz, Michael Hayes, Matthew Van Den Broeke

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The National Weather Service (NWS) advises the public to go to an interior room on the lowest level of their houses when a tornado warning is issued for their area. As the NWS Central Region Service Assessment of the Joplin, Missouri Tornado published in July 2011 reveals, however, this is often not the first action taken after learning that there is danger of being hit by a tornado. Rather, people need to seek confirmation from more than one source before following the recommended action. The goal of this research project is to determine how the number of sources and what …


Superpositioning High Power Lasers For Mid-Air Image Formations, Auston Viotto Apr 2017

Superpositioning High Power Lasers For Mid-Air Image Formations, Auston Viotto

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This research evaluates different methods to create voxels, 3-dimensional pixels, in air without the need for special glasses or reflections off of surfaces. Research on the advantages of superimposing or the culmination, focusing, of laser light will be conducted. The point of superpositioning/culmination will be evaluated by the brightness of the voxel due to the Rayleigh Scatter Effect. The voxel’s brightness is dependent on the laser output strength and inversely proportional to its wavelength. Once a superimposed/culminated voxel has been created in the lab the next step will be to manipulate the location of the voxel through 3-dimensional space. This …


Shocked Quartz Distribution, Andrew Mason Jan 2017

Shocked Quartz Distribution, Andrew Mason

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Shocked quartz is typically used to test if sites experienced a meteorite impact in the past, however, sediment is readily transported by both earthly and extraterrestrial processes that blur the lines of where impact sites are on earth. The specific deformations in the clasts themselves reveal much about their origin and present location.


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.


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 …


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 …


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.


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, …