Earth Sciences Commons^™

Free And Forced Vibrations Of Elastically Restrained Cantilever With Lumped Oscillator, Alireza Babaei, Johné Parker, Paria Moshaver

Earth and Environmental Sciences Faculty Publications

The efficiency assessment of cantilever-based energy harvesters relies on vibrational analysis, which necessitates modi- fications aimed at enhancing efficiency. These modifications involve manipulating the fundamental frequency to lower values and encompassing a wider range of resonances within a specified bandwidth. Consequently, this paper introduces an original analytical-numerical exploration into the vibratory response of a cantilever with a novel boundary condi- tion involving an elastically restrained oscillator-spring arrangement. At the microbeam’s tip, an oscillator is elastically confined by a linear spring, resulting in a novel set of coupled governing equations and a distinct shearing boundary condition. Microbeam equations is derived from …

Volcanic Glass As A Proxy For Paleotopography Suggests New Features In Late-Miocene Oregon, Julian Cohen, John Bershaw, Richard Hugo

Geology Faculty Publications and Presentations

Volcanic glass has been used extensively as a paleoaltimeter. Deuterium (²H) concentrations in glass have been found to be stable over geologic timescales, making δ²H (also known as δD) a reliable proxy for ancient water chemistry. However, continued work revolves around better understanding how different factors affect preserved water in volcanic ash. Here, we analyze δD in the Rattlesnake Tuff (RST), a widespread ca. 7 Ma ash-flow tuff, and create a paleoisoscape to assess variations in δD across Oregon during that time. To this end, 16 ash samples were collected across central and eastern Oregon from …

A Laser Ultrasound System To Non-Invasively Measure Compression Waves In Granular Ice Mixes, J. Chris Mccaslin, T. Dylan Mikesell, Hans-Peter Marshall

Geosciences Faculty Publications and Presentations

Accurate knowledge of snow mechanical properties, including Young's modulus, shear modulus, Poisson's ratio, and density, is critical to many areas of snow science and to snow-related engineering problems. To facilitate the assessment of these properties, an innovative non-contacting laser ultrasound system (LUS) has been developed. This system acquires ultrasound waveform data at frequencies ranging from tens to hundreds of kHz in a controlled cold-lab environment. Two different LUS devices were compared in this study to determine which recorded more robust ultrasound in granular ice mix samples. We validated the ultrasound observations with poro-elastic traveltime modeling based on physical and empirical …

Rice Biomass Response To Various Phosphorus Fertilizers In A Phosphorus-Deficient Soil Under Simulated Furrow-Irrigation, Jonathan B. Brye

Crop, Soil and Environmental Sciences Undergraduate Honors Theses

Wastewater-recovered phosphorus (P), in the form of the mineral struvite (MgNH4PO4⋅6H2O), may provide a sustainable alternative to rapidly decreasing rock phosphate reserves. Struvite can be generated via chemical and/or electrochemical precipitation methods, potentially reducing the amount of P runoff to aquatic ecosystems. The objective of this greenhouse tub study was to evaluate the effects of chemically- and electrochemically precipitated struvite (CPST and ECST, respectively) on above- and belowground plant response in a hybrid rice cultivar (Gemini 214, RiceTec) grown using furrow-irrigation compared to other common fertilizer-P sources [i.e., triple super phosphate (TSP) and diammonium phosphate (DAP)] in a P-deficient silt …

A Global Analysis Of Carbon And Nitrogen Stocks In Natural And Anthropogenic Soils, Shih-Chieh Chien

Theses, Dissertations and Culminating Projects

In terrestrial biomes, soils possess the highest amount of carbon and nitrogen stocks that regulate biogeochemical processes and provide ecosystem services. The amount of carbon and nitrogen stored in soils, as a balance of nutrient influxes and outfluxes, is controlled by various environmental and soil factors, while at the same time soil carbon and nitrogen stocks can be subject to anthropogenic impacts, like nutrient storage in urban soils. To inform a better, general understanding of carbon and nitrogen distribution in urban soils, the present dissertation gathers four articles (from Chapters 2 to 5, respectively) addressing different aspects of the issue, …

Building And Using A Hydrology Experiment For Place-Based Learning With Native American Students, Michaela Shallue

All Graduate Theses and Dissertations, Fall 2023 to Present

Geoscience has a known diversity problem, specifically a participation gap of ethnic minority representation, and it is especially severe regarding Native American representation. To address this participation gap, an identity gap needs to be addressed first. Native students need to visualize themselves as geoscientists before they can commit to geoscience programs and careers. This project uses a hands-on, place-based learning activity as an opportunity for Native students to better see themselves as geoscientists.

A portable rainfall simulator was constructed, calibrated, and refined for use in teaching concepts about rainfall, runoff, and erosion. It was employed in place-based learning exercises with …

The Effect Of Agrivoltaics On Irrigation Water Consumption In Central California, London Camba

Undergraduate Theses

An agricultural system where solar energy generation and agricultural systems are used together for mutual benefit, agrivoltaics reduces loss of water due to evaporation, particularly in drylands. Central California has faced extreme droughts, and water has become a scarce resource. However, the wide-scale use of agrivoltaics has been limited due to lack of knowledge about agrivoltaics and also the lack of funding for start-up agrivoltaics projects. Therefore, this research investigated the potential for agrivoltaics in Central California to reduce irrigation water consumption using a review of multiple crop studies using agrivoltaics to determine an optimal crop for agrivoltaics and a …

Using Strainmeters To Characterize Enhanced Geothermal Systems, Clem Laffaille

All Theses

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Coastal-Ocean And Estuarine Acidification In Long Bay, South Carolina: A Comparison Of In-Situ Water Quality Monitoring With Measured Carbonate System Parameters, Mary Olsen

Electronic Theses and Dissertations

One of the major water-quality issues impacting our coast and estuaries is coastal-ocean and estuarine acidification. Due to a relative dearth of data in the southeastern United States it is increasingly difficult to determine the full extent and intensity of this problem. This study provides the first characterization of coastal-ocean and estuarine acidification in Long Bay, SC by attempting to leverage long-term water quality data sets at two coastal-ocean pier sites using in-situ YSI EXO sondes deployed at both the surface and bottom waters along with two estuarine sites sampled by volunteer monitors using Orion star multi-meters. Discrete samples (120) …

Public Horticulture: Process And Design Of The Lincoln Botanical Garden, Brad Kindler

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Beginning in 2012, the local non-profit, The Lincoln Botanical Garden, began organizing the conceptual design and creation of a glass conservatory within a botanical garden in Lincoln, Nebraska. These proposed urban enhancements seek to fill a gap in garden amenities in the city by providing year-round access to public horticulture programming and education.

This project, Public Horticulture: Process and Design of the Lincoln Botanical Garden, documents these efforts and makes design recommendations for a themed Glacial Erratic Garden that could be constructed within the botanical garden.

Advisors: Ellen Paparozzi and Sam Wortman

Understanding The Zonal Variability In Cmip6 Projections Of Sahelian Precipitation, Emmanuel Ogwuche Audu

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

The uncertainty in model projections of future precipitation across the Sahel has persisted across many generations of Earth System Models (ESMs), with some models predicting drying and others moistening across this region. These discrepancies in future projections pose a challenge for stakeholders and decision makers. Many projections of Sahel precipitation found in the ESMs participating in the sixth phase of Coupled Model Intercomparison Project (CMIP6) show a zonal dipole in precipitation trend, with moistening across the Central and Eastern Sahel and drying projected for the Western Sahel. Previous studies have connected precipitation variability across the Sahel to changes in various …

Polarimetric Radar Signatures In Significant Severe Left-Moving Supercells, Raychel Nelson

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

Left-moving (LM) supercells, though rarer than right-moving (RM) supercells, may produce significant severe weather. However, there are very few existing studies on LM supercells, particularly polarimetric radar analyses. The upgrade of the nationwide Weather Surveillance Radar-1988 Doppler (WSR-88D) network to polarimetric capability and subsequent studies vastly improved understanding of RM supercells, but similar efforts have largely not been made for LM supercells. This study employs an automated polarimetric radar signature detection algorithm to examine a dataset of significant severe (hail ≥ 2.00”, wind ≥ 65 kts) LM supercells to quantify their polarimetric signatures. Comparisons are made with RM supercells to …

A Dual-Polarimetric Analysis Of A Large Sample Of Left-Moving Supercells, Ben Schweigert

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

Supercells have been researched extensively since they were first described over 50 years ago. They are prolific severe weather producers, responsible for the most severe hail, severe wind gusts, and tornadoes. These rotating thunderstorms require attention from forecasters to protect life and property from their threats, most effectively done with Doppler radars. While extensive amounts of radar-based investigations have been completed, they focused almost exclusively on right-moving (RM) supercells, resulting in a knowledge gap surrounding their counter-rotating (left-moving, LM) partners. This study works to fill the void by developing a dataset of LM supercells and analyzing the dual-polarimetric features observed …

Effect Of Biomass Water Dynamics In Cosmic-Ray Neutron Sensor Observations: A Long-Term Analysis Of Maize–Soybean Rotation In Nebraska, Tanessa Morris

School of Natural Resources: Dissertations, Theses, and Student Research

The precise measurement of soil water content (SWC) is crucial for effective water resource management. This study utilizes the Cosmic Ray Neutron Sensor (CRNS) for area-averaged SWC measurements, emphasizing the need to consider all hydrogen sources, including the time-variable ones like plant biomass and water content. Chapter 1 presents a background on soil moisture estimation, CRNS technology, and an overview of the study. It discusses various soil moisture measurement techniques, highlights the gap in knowledge addressed by CRNS technology, explains CRNS functionality and advancements, and outlines the study's motivations and methods.

Chapter 2 reports a study conducted near Mead, Nebraska, …

A Compilation, Analysis, And Categorization Of 403 Atmospheric And Climate Science Misconceptions, Haeli Leighty

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

The National Association of Geoscience Teachers (NAGT) has listed the inaccessibility of research related to misconceptions in atmospheric and climate science as a Geoscience Education Research Grand Challenge (Cervato et al. 2018). This project was a direct response to this call for research and consisted of three distinct steps: 1) data gathering, which included reviewing the literature for relevant misconception data, 2) a qualitative analysis, which included compiling, organizing, and categorizing the data collected, and 3) a quantitative analysis, which included determining the prevalence of each misconception across topic categories, demographic categories, and over time. A total of 403 misconceptions …

The Use Of Laja In Construction In Ancient Mesoamerica: A View From The Southern Gulf Lowlands Of Veracruz, Mexico, Lauren Smith

Honors College Theses

The archaeology of the southern Gulf lowlands of Veracruz, Mexico is notable for its research pertaining to the Olmec culture (Jaime-Riveron 2016; Loughlin 2012; Pool 2006). The region was home to the Colossal Olmec Heads: large, easily identifiable sculptures crafted from the volcanic rock of the Tuxtlas Volcanic Field. The use of volcanic resources in such grand presentations may instill a bias in the research of some archaeologists, but it is important to consider how these and other volcanic resources might have been used in everyday life (e.g., Jaime-Riveron 2016: 86). The consolidated volcanic ash in this region is referred …

Climate And Channel Morphology Control Stream Drying Across Scales, Mac Beers

Boise State University Theses and Dissertations

Over half of the global stream network is estimated to dry for at least one day of the year. Streams that dry at some point in space and time are considered intermittent. Intermittent streams exhibit one of three hydrologic states: flowing, non-flowing pools, and dry. The distribution and extent of completely dry channel and non-flowing pools is important for water quality and ecology, however, we are currently unable to accurately predict when, where, and how streams dry at small scales. Few studies have investigated the stream characteristics that influence local scale controls of drying, and more work is needed to …

Improved Hydrologic Modeling And Geophysical Imaging Of Critical Zones: Incorporating Structural And Temporal Constraints, Hang Chen

Boise State University Theses and Dissertations

The Earth's critical zone (CZ) is a life-sustaining layer extending from the canopy of the tree to the bottom of the active groundwater circulation, providing valuable resources to terrestrial life, including nutrients, minerals, and fresh water. There are many challenges in studying various processes within and the function of the CZ. This dissertation addresses two common challenges in studying the CZ hydrology and watershed function, which are critical for a predictive understanding of the water dynamics in mountainous terrain and for an informed management of future water resources under rapid climate change. These challenges include (1) accurate quantification of hydrological …

Triggers Of Rapid Change In Glacier Dynamics, Jukes Liu

Boise State University Theses and Dissertations

The loss of land ice has become the greatest contributor to global mean sea level rise since 2006 (Oppenheimer et al., 2019). Glaciers have contributed ∼20% to global sea level rise over the last ∼2 decades (Oppenheimer et al., 2019; Hugonnet et al., 2021), while the ice sheets have contributed 33% (Oppenheimer et al., 2019). For the outlet glaciers and ice streams that drain the Greenland and Antarctic ice sheets, changes to their dynamics (flow speed, thickness, and length) dominate their present and future mass loss (King et al., 2020; Diener et al., 2021). One of the main limitations in …

Investigating The Distribution Of Soil Inorganic Carbon, And The Role Of Dust Deposition In Dryland Soils, Zahra Ghahremani

Boise State University Theses and Dissertations

The importance of dust deposition in the biogeochemical cycling of nutrients, sediment redistribution, and soil formation is well-known. Anthropogenic activities such as changing land use and agricultural practices can influence dust flux deposition rates, dust organic matter content, and the chemical composition of dust. This study examines the influence of agricultural activities on aeolian deposition in a the xeric intermontane westerns USA. We investigate seasonal and spatial variations in dust deposition rates, dust organic matter, dust inorganic matter, and dust geochemistry from passive dust traps. The Reynolds Creek Experimental Watershed (RCEW; Owyhee Mountains, Idaho) and the Northwest Irrigation and Soils …

Agricultural Irrigation Water Quality In The Lower Boise River Basin: A Quantitative Assessment Of Canal Ecosystem Metabolism And Escherichia Coli Spatiotemporal Variability, Reed Chasmar

Boise State University Theses and Dissertations

Irrigation canals are pervasive in agricultural landscapes. Despite their vast spatial extent and significant volumetric impact on the hydrologic cycle, the role of irrigation canals as intermittent channels within a river network, as well as their various functions (e.g., supporting aquatic ecosystems, transporting microbial communities, altering the carbon cycle), are not well understood. Microbial water quality and aquatic ecosystem metabolism represent two mechanisms to assess stream channels that can provide new insights into the complex dynamics and spatiotemporal patterns that exist in irrigation canals, which has relevance for both human health and for the field of stream ecology. The goal …

On The Use Of Elastic Waves To Study Snow Microstructure And Mechanical Properties: A Look From The Lenses Of Laser Ultrasound And Time-Lapse Seismic, J. Christopher Mccaslin

Boise State University Theses and Dissertations

Accurate knowledge of the mechanical and microstructural properties of snow is essential to improve snow science and engineering applications. In this dissertation, I investigated the use of ultrasound to quantify certain snow properties with a non-contacting laser ultrasound system (LUS), then I applied the knowledge gained from a small controlled lab-based method to a larger field-based active-source seismic method.

I first evaluated two different LUS devices to determine which one produced more accurate ultrasound observations in analog snow (i.e. shaved ice). The PSV-400 Scanning Vibrometer was found to provide higher quality ultrasound observations compared to the VibroFlex Fiber Vibrometer. Using …

Introduction To Nuclear Magnetic Resonance Spectroscopy In A Geochemical Setting, Evan Mack

University Honors College

Nuclear magnetic resonance (NMR) spectroscopy is a powerful analytical tool that is heavily employed in organic chemistry, but lacks use in geochemistry. The technique is most useful for characterization and structural analysis of analytes, but also sees use in kinetics analysis, speciation, and detection. This work aims to answer these questions regarding NMR spectroscopy’s use in geochemical settings: Which nuclei are studied? For what purposes is each nucleus studied? What affects the scope of the technique and has caused it to not be widely used? How often is NMR spectroscopy used? What trends are there in the technique’s use? The …

College Of Natural Sciences Newsletter, Spring 2024, College Of Natural Sciences

College of Natural Sciences Newsletters and Reports

Page 1 Dean's Message
Page 2 New Faculty and New Club on Campus
Page 3 2024 URSCAD Awards
Page 4 Day of Scholars 2024
Page 5 SDSU's First Representation at the Association for Anatomy's 2024
Annual Conference
Page 6-7 2024 Honor's College Convocation
Page 8 Other Student Activities
Page 9 Faculty Awards
Page 10-11 Other News
Page 12 2024 Drone Day and American Association of Geographers Convention - Hawaii
Page 13 55th Annual Geography Convention
Page 14 2024 Stethoscope Ceremony
Page 15 Open PRAIRIE Data

The Effects Of Amphibole- And Sulfide-Producing Melts On Crustal Strength In Gabbros Of Lower Oceanic Crust In Oceanic Core Complexes, Mid-Atlantic And Southwest Indian Ridges, Trevor Hoffmann

Master's Theses

This study investigates gabbro-cored oceanic core complexes in the slow-spreading Mid-Atlantic Ridge (MAR) and the ultraslow spreading Southwest Indian Ridge (SWIR). Dikelets are a texture found in thin section samples from these systems that form as a result of crystal-plastic deformation. Thin section samples from the Atlantis Massif, MARK Area, and 13˚-15˚ North of the MAR and the Atlantis Bank of the SWIR were observed with petrography to find these dikelets and identify what type of dikelet is present. SEM-EDS is used to identify the mineral assemblages present in the dikelets. LA-ICP-MS is used on amphibole to determine if its …

Geologic Face Mapping Methodology Utilizing Global Positioning Systems And Unmanned Aircraft Systems, Luke Whitenburg

Electronic Theses and Dissertations

Geologic field mapping has traditionally been a low-technology process, limited by time in the field and a delicate balance between data collection and coverage area. Advancements in Global Positioning Systems (GPS), Unmanned Aircraft Systems (UAS), and software packages offer new tools and techniques for collecting high volume, accurate geologic information. These tools can provide geologists with safe and efficient ways to collect and process greater volumes of field data.

Field data for this study was collected from three open pit mines using a Trimble Geo 7X GPS unit with Geo 7 Series Rangefinder module and a Phantom 4 Pro V2.0 …

Ecological Dynamics Of Cenozoic North American Mammals, Alexandria Brandis Shupinski

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Understanding how community structure is affected by various ecological, climatic, and environmental changes is a long-standing goal in ecology. However, disentangling human impacts from these other variables is difficult when using short modern timescales and anthropogenically altered communities. The fossil record provides a means to investigate community structure dynamics across critical intervals, excluding humans as a variable. Here, in three studies, I assess changes in North American mammal paleocommunity structure across the last 66 million years (Ma) at multiple temporal and spatial scales. In Chapter 1, I identify changes in mammal functional diversity (FD) locally and continentally, using three independent …

Soil Carbon Sequestration Efforts In Arid And Semi-Arid Climates Under Conservation Agriculture And Reforestation, Samantha Lynn Colunga

Theses and Dissertations

Soil organic carbon (SOC) plays a vital role in the global carbon cycle and aids in climate change mitigation. However, deforestation and intensive agricultural practices threaten topsoil and carbon (C) pools through soil disturbances releasing vast amounts of carbon dioxide (CO2) by enhancing the decomposition of organic materials. Degraded soils typically lack stable aggregates, nutrient and water retention, and overall low fertility. In arid and semi-arid regions, soils are in an even more dire situation, as low precipitation and high temperatures slow down the accumulation of SOC. This thesis has two objectives: 1) to evaluate whether conservation tillage practices increase …

Sustainable Fertilizer Management Practices For Container Nursery Production, Saroj Burlakoti

All Graduate Theses and Dissertations, Fall 2023 to Present

Growing nursery plants in containers requires a timely supply of mineral nutrients for optimum growth. However, there is a misconception among growers that the application of higher doses of fertilizers hastens plant growth; instead, it can lead to runoff and leaching loss of nutrients. Reducing fertilizer application while sustaining healthy plants can not only negate environmental consequences but also save fertilizer costs. For example, two ground covers, Lysimachia nummularia (creeping jenny, moneywort) and Vinca minor 'Bowles' (periwinkle), can be grown for three months by applying 6 mg/L of phosphorus (P) as reduction of P to single application of 6 mg/L …

Year-Round Co2 Emissions From The Drawdown Area Of A Tropical Reservoir: Strong Seasonal And Spatial Variation, Ícaro Barbosa, José R. Paranaíba, Sebastian Sobek, Sarian Kosten, Rafael M. Almeida, Vitor Duque, Natália Mendonça, Nathan Barros, Raquel Mendonça

School of Earth, Environmental, & Marine Sciences Faculty Publications

Highlights

• Drawdown areas emitted 80% of reservoir CO2 with just 1/5 area.

• Emissions from reservoir shorelines near forests were greater than from areas near grassland.

• CO2 emissions increase with the distance from the water.

• Estimates of reservoir drawdown CO2 flux vary by ∼ 300 % across the seasons examined here.

• There was no discernible difference in CO2 emissions between day and night-time.

• A significant increase in CO2 fluxes was observed 30 min after a rewetting event.

Abstract

A growing body of literature points to drawdown areas as important sources of atmospheric CO2 within reservoirs. Yet seasonal and temporal patterns of …