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Articles 10921 - 10950 of 59516

Full-Text Articles in Earth Sciences

Machine Learning-Based Methods For The Segmentation Of Scanning Electron Microscopy Images Of Fine-Grained Shale Samples, Binqian Yin Dec 2022

Machine Learning-Based Methods For The Segmentation Of Scanning Electron Microscopy Images Of Fine-Grained Shale Samples, Binqian Yin

Earth & Environmental Sciences Dissertations - Archive

The segmentation of scanning electron microscopy (SEM) images is critical yet time-consuming for geological studies, as it will need to differentiate the boundaries for different mineral objects to facilitate subsequent analyses, such as porosity calculation. Recently, machine learning methods, especially convolutional neural networks (CNNs), have been explored to segment SEM images for fine-grained shale samples. However, existing methods fail to address two critical issues in the segmentation of shale rock images---insufficient labeled data and imbalanced objects. To this end, this dissertation has proposed a machine learning pipeline that consists of supervised, semi-supervised, and active learning stages to reduce manual efforts …


Remote Sensing Application For Landslide Detection: Monitoring Along Eastern Lake Michigan (Miami Park, Mi), Guzalay Sataer Dec 2022

Remote Sensing Application For Landslide Detection: Monitoring Along Eastern Lake Michigan (Miami Park, Mi), Guzalay Sataer

Dissertations

I assessed the nature and spatial and temporal patterns of deformation over the Miami Park bluffs on the eastern margin of Lake Michigan and investigated the factors controlling its observed deformation. Our approach involved the following steps: (1) extracting bluff deformation rates (velocities along the line of sight of the satellite) using a stack of Sentinel-1A radar imagery in ascending acquisition geometry acquired between 2017 and 2021 and applying the Intermittent Small Baseline Subset (ISBAS) InSAR time series analysis method; (2) generating high-resolution (5 cm) elevation models and orthophotos from temporal unmanned aerial vehicle (UAV) surveys acquired in 2017, 2019, …


Applications Of Micro-X-Ray Fluorescence (Μxrf) Techniques To Ore Formation Questions In Economic Geology, Hannah Adwoa Buamono Dec 2022

Applications Of Micro-X-Ray Fluorescence (Μxrf) Techniques To Ore Formation Questions In Economic Geology, Hannah Adwoa Buamono

Open Access Theses & Dissertations

Advances in x-ray optics over the past decade have enabled a new generation of benchtop micro energy-dispersive x-ray fluorescence (µXRF/EDS) instruments to analyze samples with an x-ray spot size of 25 microns or less and detection limits of tens to hundreds of parts per million. The analysis of samples from mineral (ore) deposits may illustrate some of the capabilities and limitations of these instruments applied to geoscience problems. The qualitative elemental analysis process allows the production of detailed elemental maps which, together with line scan profiles and other petrographic and geochemical evidence, leads to a better definition of key chemical, …


Mgrre_Thinsections_Mgrre-129_6, Mgrre Dec 2022

Mgrre_Thinsections_Mgrre-129_6, Mgrre

Thin Sections

No abstract provided.


Mgrre_Thinsections_Mgrre-129_2, Mgrre Dec 2022

Mgrre_Thinsections_Mgrre-129_2, Mgrre

Thin Sections

No abstract provided.


Mgrre_Thinsections_Mgrre-129_5, Mgrre Dec 2022

Mgrre_Thinsections_Mgrre-129_5, Mgrre

Thin Sections

No abstract provided.


Mgrre_Thinsections_Mgrre-129_7, Mgrre Dec 2022

Mgrre_Thinsections_Mgrre-129_7, Mgrre

Thin Sections

No abstract provided.


Storm Intensity And Forward Speed Controls On Back-Barrier And Shoreface Sediment Dynamics Along The Louisiana Coast, Md Mohiuddin Sakib Dec 2022

Storm Intensity And Forward Speed Controls On Back-Barrier And Shoreface Sediment Dynamics Along The Louisiana Coast, Md Mohiuddin Sakib

LSU New Orleans Theses and Dissertations

High energetic storms import sediment to back-barrier bays and marshes and produce a perennial footprint that contributes to the long-term evolution of the inner shelf, bays, and marsh platform. The magnitude of sedimentation in back-barrier bays and marshes varies with storm characteristics (e.g., storm intensity, forward speed, size, and track). However, quantifying the impacts of storm characteristics on the sediment exchange between the inner shelf, bays, and marshes and documenting the resulting net sediment import and export patterns across these interfaces remains largely unexplored. Here we applied a calibrated Delft3D hydrodynamics and sediment transport model to a microtidal bay-marsh complex …


Geology, Soils And Climate Of Western Australia's Wine Regions, Peter J. Tille, Angela Stuart-Street, Peter S. Gardiner Dec 2022

Geology, Soils And Climate Of Western Australia's Wine Regions, Peter J. Tille, Angela Stuart-Street, Peter S. Gardiner

Bulletins 4000 -

This bulletin details what is special and unique about the geology, soil and climate of the south-west of Western Australia (WA), an area that encompasses the state’s 9 wine regions.

We have arranged the information into 2 parts:

  • In Part 1, we broadly describe the special geological, soil and climate features of the south-west of WA to provide context for the wine regions.
  • In Part 2, we describe the geology, soil and climate of the regions and subregions of the Geographical Indications (GI) scheme (administered by Wine Australia) for WA.

Through this work we have found that the wine regions …


Using Landsat Satellite Imagery To Estimate Groundcover In The Grainbelt Of Western Australia, Justin Laycock, Nick Middleton, Karen Holmes Dec 2022

Using Landsat Satellite Imagery To Estimate Groundcover In The Grainbelt Of Western Australia, Justin Laycock, Nick Middleton, Karen Holmes

Resource management technical reports

Maintaining vegetative groundcover is an important component of sustainable agricultural systems and plays a critical function for soil and land conservation in Western Australia’s (WA) grainbelt (the south-west cropping region). This report describes how satellite imagery can be used to quantitatively and objectively estimate total vegetative groundcover, both in near real time and historically across large areas. We used the Landsat seasonal fractional groundcover products developed by the Joint Remote Sensing Research Program from the extensive archive of Landsat imagery. These products provide an estimate of the percentage of green vegetation, non-green vegetation and bare soil for each 30 m …


Physical Controls On The Hydrology Of Perennially Ice-Covered Lakes, Taylor Valley, Antarctica (1996-2013), J. M. Cross, Andrew G. Fountain, M. J. Hoffman, M. K. Obryk Dec 2022

Physical Controls On The Hydrology Of Perennially Ice-Covered Lakes, Taylor Valley, Antarctica (1996-2013), J. M. Cross, Andrew G. Fountain, M. J. Hoffman, M. K. Obryk

Geology Faculty Publications and Presentations

The McMurdo Dry Valleys, Antarctica, are a polar desert populated with numerous closed-watershed, perennially ice-covered lakes primarily fed by glacial melt. Lake levels have varied by as much as 8 m since 1972 and are currently rising after a decade of decreasing. Precipitation falls as snow, so lake hydrology is dominated by energy available to melt glacier ice and to sublimate lake ice. To understand the energy and hydrologic controls on lake level changes and to explain the variability between neighboring lakes, only a few kilometers apart, we model the hydrology for the three largest lakes in Taylor Valley. We …


Dynamic Soil Properties In The Lower Rio Grande Valley: Understanding Responses Of Infiltration Rate, Bulk Density, Aggregate Stability To Different Tillage Practices, Temiloluwa Faith Awotoye Dec 2022

Dynamic Soil Properties In The Lower Rio Grande Valley: Understanding Responses Of Infiltration Rate, Bulk Density, Aggregate Stability To Different Tillage Practices, Temiloluwa Faith Awotoye

Theses and Dissertations

Dynamic Soil Properties (DSPs) are soil properties that change in response to both natural and human-caused interruptions and pressures such as agro-based and wildland management. These soil properties can transform for months or even years in response to the farm use and management procedures. This research project investigates the relationship between different dynamic soil physical properties and tillage practices in the Texas Hidalgo sandy clay loam benchmark soil series. Data analyses was done to compare the effect of tillage to these soil physical properties and build a discussion about relationships between on-farm practices to other aspects of farm viability. We …


Dynamic Soil Properties In The Lower Rio Grande Valley: Carbon And Nitrogen Responses To Different Tillage Practices, Luzyannet Ballesteros Gonzalez Dec 2022

Dynamic Soil Properties In The Lower Rio Grande Valley: Carbon And Nitrogen Responses To Different Tillage Practices, Luzyannet Ballesteros Gonzalez

Theses and Dissertations

There has been increased attention in utilizing agriculture for carbon sequestration. Soil carbon and nitrogen are two dynamic soil properties (DSPs) that are indicators of soil health and function and have overlapping cycles. These soil properties change frequently as a result of environmental conditions and agricultural management practices. This study focuses on the impact of tillage practices in unirrigated agricultural fields in Hidalgo and Willacy counties located in South Texas on Hidalgo Sandy Clay Loam; With a particular focus on Soil Total Carbon (TC), Soil Inorganic Carbon (SIC), Permanganate Oxidizable Carbon (POXC), Carbon and Nitrogen ratio (C:N), Soil Organic Matter …


Conjunctive Management For Groundwater-Surface Water Resources: Numerical Modeling And Potential Assessment Of Managed Aquifer Recharge (Mar) At Lower Rio Grande Valley In South Texas, Dwight Zedric Q. Capus Dec 2022

Conjunctive Management For Groundwater-Surface Water Resources: Numerical Modeling And Potential Assessment Of Managed Aquifer Recharge (Mar) At Lower Rio Grande Valley In South Texas, Dwight Zedric Q. Capus

Theses and Dissertations

Texas is well known to frequent floods and droughts, and yet has mounting concerns in very imbalanced water availability and water demands from growth in population and economical activities. Capturing and storing water is essential to long-term and climate-smart management of the “already-scarce” water resources. This study aimed to apply numerical modeling to evaluate potentials and impacts of Managed Aquifer Recharge (MAR) to regional groundwater systems in the Lower Rio Grande Valley. Using Visual MODFLOW Flex 3D package, different scenarios were simulated for groundwater flow patterns and storage capacities. Water injections tested ranged between 7.30x105 ft3 to 3.65x109 ft3 , …


An Assessment Of Physical And Microbial Dynamic Properties Sensitive To Tillage Practices In Hidalgo Sandy Clay Loam Soils, Rocio N. Hernandez Dec 2022

An Assessment Of Physical And Microbial Dynamic Properties Sensitive To Tillage Practices In Hidalgo Sandy Clay Loam Soils, Rocio N. Hernandez

Theses and Dissertations

Mechanized tillage is known to impact the dynamic physical, biological and chemical properties of a given soil, and as a result, can cause systematic harm to the soil’s function (Alam et al., 2014). The aim of this study is to assess how a series of land management tillage practices will impact dynamic physical and biological soil health parameters such as aggregation, carbon, respiration, and enzymatic activity (β-glucosidase). According to Acir et al (2020), the aforementioned soil parameters are both co-influenced and dependent, indicating a response to tillage is likely. A total of 198 samples of Hidalgo series soils were collected …


Water Hardness Removal By Electrochemical Precipitation In A Continuous Flow Condition Using Conductive Concrete As Cathode, Tahsin Tareque Dec 2022

Water Hardness Removal By Electrochemical Precipitation In A Continuous Flow Condition Using Conductive Concrete As Cathode, Tahsin Tareque

Theses and Dissertations

This study focuses on the electrochemical precipitation (EP) process to reduce excess water hardness from the Lower Rio Grande Valley (LRGV) tap water using electrically conductive concrete as cathode in a continuous flow condition. LRGV tap water is extremely hard with hardness more than 350 mg/L as CaCO3. Humans can pleasantly consume water with hardness less than 150 mg/l as CaCO3 according to World Health Organization (WHO). Hard water is also known to cause mechanical problems to boilers and heat exchangers. In this process, electricity is passed through electrodes submerged in electrolyte, which causes an alkaline environment around the cathode …


Fossil Mammals From Hickory Tree Cave, Sullivan County, Tennessee, Alexis Rivera Dec 2022

Fossil Mammals From Hickory Tree Cave, Sullivan County, Tennessee, Alexis Rivera

Electronic Theses and Dissertations

Hickory Tree Cave, also known as Big Spring Cave, is located in the southern Appalachians and is known for fossils that are considered to be Quaternary in age. Fossil mammals were identified and assigned to the lowest taxonomical level possible. Most remains are fragmented or digested and it seems likely that various taphonomic processes are responsible for the resulting assemblage. The site lacks the extreme boreal component of Pleistocene cave faunas in the region (e.g. Baker Bluff Cave), with most reported taxa inhabiting Appalachian deciduous forest environments in North America today. While the presence of tapir (Tapirus sp.) …


“This Isn't Working For Me. Can We Do It A Different Way?" The Lived Experiences Of Geoscience Students With Learning Disabilities, Nina Morris Dec 2022

“This Isn't Working For Me. Can We Do It A Different Way?" The Lived Experiences Of Geoscience Students With Learning Disabilities, Nina Morris

Masters Theses

The purpose of this exploratory qualitative study is to better understand the lived experiences of geoscience students with learning disabilities in their geoscience classes. Students with learning disabilities bring a unique perspective while also facing unique challenges in post-secondary education. In the literature, there is limited information on what support and teaching strategies are beneficial to this population. Undergraduate and graduate geoscience students who identify as having a learning disability from colleges and universities in the United States were recruited. Six students consented to participate in the study, and each completed a semi-structured interview. Semi-structured interviews were designed to prompt …


Exploring The Effects Of Tree Roots On Infiltration Process, Nazife Onaral Dec 2022

Exploring The Effects Of Tree Roots On Infiltration Process, Nazife Onaral

Masters Theses

Effects of the root structures on soil infiltration dynamics are not clearly defined. Imaging the complex tree root structures and movement of water through the root ball is a challenging task to achieve without damaging the trees and roots by conventional methods. Commonly used methods are invasive, labor-intensive, and not easily accessible. Ground Penetrating Radar (GPR) has commonly been used to characterize soil profiles and it can be a reliable tool to map complex root structures with a novel high-resolution circular data collection technique. Electrical resistivity tomography (ERT) is another reliable geophysical method to image infiltration processes by the change …


Ligand-Promoted Dissolution Of Uranyl Phosphate Across Scales, Brennan Ferguson Dec 2022

Ligand-Promoted Dissolution Of Uranyl Phosphate Across Scales, Brennan Ferguson

All Dissertations

The formation of uranyl phosphate precipitate is a remediation strategy because the low solubility of uranyl phosphate minerals, like chernikovite, limits the mobility of uranium in contaminated soils. However, organic ligands can complex with aqueous metal cations to form more soluble species. For example, citrate is a commonly occurring organic ligand produced by plants and microbes that increases the solubility of uranium and therefore the dissolution of uranyl phosphate minerals in the uranyl phosphate-citrate system. This effect is an important control on the mobility of uranium in organic-rich, and near-surface vegetated environments. Nevertheless, key aspects of the citrate-uranyl phosphate system …


Grapefruit Peel Biochar Applications For Immobilizing Copper And Lead In Soil, Michael Alfredo Navarro Dec 2022

Grapefruit Peel Biochar Applications For Immobilizing Copper And Lead In Soil, Michael Alfredo Navarro

Theses and Dissertations

This study investigated the efficacy of grapefruit peel (GP) derived biochar materials (two pyrolysis temperatures 450°C and 800°C) as a potential adsorbent to immobilize heavy metal (copper and lead) in a local sandy loam clay soil. A batch adsorption test with heavy metal concentrations at 50 mg L-1, and 100 mg L-1 revealed that soil itself had the highest immobilization percentage compared to the GP biochars. A soil column experiment was conducted to determine how much the GP biochar samples and the tested soil will exhibit adsorptive characteristics for heavy metals when 50 ml of 50 mg L-1 copper or …


Groundwater Modelling Of The Newman Area For Managed Aquifer Recharge Assessment, Wolfgang Schmid, Rodrigo Rojas, Michael J. Donn, Christopher Schelfhout Dr, Mathias Raiber, Olga Barron Dec 2022

Groundwater Modelling Of The Newman Area For Managed Aquifer Recharge Assessment, Wolfgang Schmid, Rodrigo Rojas, Michael J. Donn, Christopher Schelfhout Dr, Mathias Raiber, Olga Barron

Natural resources commissioned reports

This report contributes to the Transforming Agriculture in the Pilbara (TAP) initiative that has been developed to undertake the detailed studies in the Pilbara to bring suitable medium to large scale irrigation land to market for private investment. The research objective was to explore opportunities for irrigated agriculture north of Newman (Eastern Pilbara), deploying managed aquifer recharge (MAR) to secure water for irrigation. MAR source water identified was from mine dewatering surplus, generated from the large BHP Iron Ore operation in the Newman region. The objectives of this report were to:

  • conceptualise the groundwater system and associated processes in the …


Glacier Segmentation From Remote Sensing Imagery Using Deep Learning, Bibek Aryal Dec 2022

Glacier Segmentation From Remote Sensing Imagery Using Deep Learning, Bibek Aryal

Open Access Theses & Dissertations

Large-scale study of glaciers improves our understanding of global glacier change and is imperative for monitoring the ecological environment, preventing disasters, and studying the effects of global climate change. In recent years, remote sensing imagery has been preferred over riskier and resource-intensive field visits for tracking landscape level changes like glaciers. However, periodic manual labeling of glaciers over a large area is not feasible due to the considerable amount of time it requires while automatic segmentation of glaciers has its own set of challenges. Our work aims to study the challenges associated with segmentation of glaciers from remote sensing imagery …


Reprocessing Groundwater Resistivity Surveys In The Lower Mesilla Basin, New Mexico, And Texas, Leslie Bernal Dec 2022

Reprocessing Groundwater Resistivity Surveys In The Lower Mesilla Basin, New Mexico, And Texas, Leslie Bernal

Open Access Theses & Dissertations

The Mesilla Basin is part of the Rio Grande Basin System. Its northern boundary is definedby the Doña Ana Mountains in New Mexico and to the south by Sierra San Blas, Sierra Almirez, and Sierra La Candelaria in Mexico, where the basin changes its name to Conejos-Médanos. It supplies water for irrigation and public use to the cities of Las Cruces, NM, El Paso, TX, and Ciudad Juárez, Mexico. The southern part of the basin in the U.S. territory, known as the Lower Mesilla Basin, is bounded to the east by the Franklin Mountains, to the west by the Potrillo …


Hydrothermal Alteration Targeting And Geophysical Mineral Exploration Of Eureka And Sylvanite Mining Districts, Southwest New Mexico, Kenneth Singh Dec 2022

Hydrothermal Alteration Targeting And Geophysical Mineral Exploration Of Eureka And Sylvanite Mining Districts, Southwest New Mexico, Kenneth Singh

Open Access Theses & Dissertations

As part of the southwestern North American porphyry copper province, mining of natural resources in New Mexico has historically played a crucial role in economic development for over 150 years including this project area in the Little Hatchet Mountains. The northern half of the Little Hatchet Mountains lies in Grant County and includes the Eureka Mining District (EMD) whereas the southern half is in Hidalgo County and includes the Sylvanite Mining District (SMD), 38 miles southeast of Lordsburg. The EMD, a copper and silver-lead mining district from 1880-1961, had a total estimated production from the Laramide veins of 2.9 million …


Decision Making Under Uncertainty With A Special Emphasis On Geosciences And Education, Laxman Bokati Dec 2022

Decision Making Under Uncertainty With A Special Emphasis On Geosciences And Education, Laxman Bokati

Open Access Theses & Dissertations

In many practical situations, we need to make a decision. In engineering, we need to decideon the best design of a system, and, for existing systems - on the best control strategy. In financial applications, we need to decide what is the best way to invest money. In geosciences, we need to decide whether we should explore a possible mineral deposit - or whether we should perform more experiments and measurements (and what exactly). In some cases, we can compute the exact consequences of each decision - e.g., if we are controlling a satellite. However, in many other cases, we …


Implementation Of Structure From Motion (Sfm) Technology For Edcuational Lessons, Valeria Veronica Martinez Dec 2022

Implementation Of Structure From Motion (Sfm) Technology For Edcuational Lessons, Valeria Veronica Martinez

Open Access Theses & Dissertations

Education is the most important obligation the humanity race has in order to evolve and thrive in the modern world. There are various applications for educators to teach valuable lessons to students, and not all deliveries will be the same for every lesson and for every student. Lesson being taught, the lesson delivery from educator to student often changes every time the lesson is implemented, depending on the learning ability of the students. Students have the ability to learn in different ways, such as the visual, auditory, kinesthetic, reading and writing learners (Oxford 2003). As educators aware of the four …


Using Ground Penetrating Radar To Investigate Controls On Pedogenic Calcium Carbonate Distribution In Dryland Critical Zones, Nohemi Valenzuela Garay Dec 2022

Using Ground Penetrating Radar To Investigate Controls On Pedogenic Calcium Carbonate Distribution In Dryland Critical Zones, Nohemi Valenzuela Garay

Open Access Theses & Dissertations

Caliche or pedogenic calcium carbonate (CaCO3) layers are a common feature of arid soils, but the environmental controls on their distribution are not fully understood. Caliche layers are thought to play an important role in shallow subsurface water storage and movement, due to their water retention capacity and ability to impede vertical water transport (Hennessy et al., 1983). Therefore, caliche distribution and stability play a role in controlling water distribution in arid lands. However, due to its largely subsurface nature, caliche can be difficult to investigate and map without significant effort. I hypothesize that noninvasive geophysical methods, such as ground-penetrating …


Pleistocene Deposits Of Lower Wahweap Creek And Its Tributaries, Southern Utah, Noah Slade Dec 2022

Pleistocene Deposits Of Lower Wahweap Creek And Its Tributaries, Southern Utah, Noah Slade

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The famous landscapes of the Colorado Plateau have been created over millions of years, primarily by erosive forces of wind and water. Interruptions in the long-term erosion of the landscape occur when streams gain more sediment than they can transport, which causes deposition along channels and floodplains. The resulting sequences of terrace deposits are used by geologists to study when and how river systems have evolved.

Mammoth bones were recently discovered in stream deposits along Wahweap Creek, a tributary of the Colorado River in southern Utah. Previous work indicates that the deposits pre-date the last ice age, making it one …


Investigating The Use Of Quartz Luminescence And Rock-Color Alteration To Characterize Wildfire Exposure; Applied To The 2020 Mangum Fire, Kaibab Plateau, Arizona, April I. Phinney Dec 2022

Investigating The Use Of Quartz Luminescence And Rock-Color Alteration To Characterize Wildfire Exposure; Applied To The 2020 Mangum Fire, Kaibab Plateau, Arizona, April I. Phinney

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Wildfires appear to be increasing in size, severity, and frequency. Land managers need information on past wildfire behavior to make effective and adaptive land management plans. However, there are only a few techniques and data sources that provide information on past fire heating. This study aims to provide new methods to equip managers with a more robust understanding of historic and modern fire behavior. Fire behavior is assessed using novel methods that can assess soil and rock response to past wildfire heat exposure.

This study examined samples from the 2020 Mangum Fire, in northern Arizona. Sediment and rock were gathered …