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2022

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Articles 6451 - 6480 of 6506

Full-Text Articles in Earth Sciences

Soil Hydro-Physical Properties, Computed Tomography Measured Pore Parameters, And Soil Health Indicators As Influenced By Tillage And Crop Rotation Systems, Goutham Thotakuri Jan 2022

Soil Hydro-Physical Properties, Computed Tomography Measured Pore Parameters, And Soil Health Indicators As Influenced By Tillage And Crop Rotation Systems, Goutham Thotakuri

Electronic Theses and Dissertations

Long-term tillage and crop rotation systems are important agricultural management practices as these can have direct impact on the soil’s key properties. The objectives of this study were to (ⅰ) quantify the soil pore characteristics under long-term tillage and crop rotation using X-ray computed tomography (XCT) and to assess the relationships between XCT-measured pore parameters and soil hydro-physical properties; and (ⅱ) evaluate the impacts of long-term tillage and crop rotation on select soil health indicators. The objective (ⅰ) was carried out at Haskell Agricultural Laboratory (HAL), Concord, NE; and objective (ⅰi) was carried out at South Central Agricultural Laboratory (SCAL), …


It's Not Just No-Till: Crop Rotations Are Key To Improving Soil Quality And Grain Yields At Dakota Lakes Research Farm, Natalie Sturm Jan 2022

It's Not Just No-Till: Crop Rotations Are Key To Improving Soil Quality And Grain Yields At Dakota Lakes Research Farm, Natalie Sturm

Electronic Theses and Dissertations

No-till is increasingly promoted as a vital agricultural practice to address the challenge of improving soil quality while maintaining the ability to produce food, feed, fuel, and fiber. However, questions remain regarding 1) how different crop rotations impact soil quality under no-till management specifically and 2) whether significant improvements in soil quality can be made without negatively impacted crop yields. In this study, we demonstrate that even under the same long-term no-till management, differences in grain yields and soil biological, chemical, and physical properties exist between crop rotations at Dakota Lakes Research Farm in central South Dakota. We propose that …


Combining Soil Health And Fertility Measurements To Improve The Accuracy Of Predicting Corn Grain Yield Responses To P And K Fertilization, Benjamin Groebner Jan 2022

Combining Soil Health And Fertility Measurements To Improve The Accuracy Of Predicting Corn Grain Yield Responses To P And K Fertilization, Benjamin Groebner

Electronic Theses and Dissertations

Researchers have pointed to changes in climate and land management practices to justify the need to reevaluate the accuracy of current South Dakota (SD) corn (Zea mays L.) P and K fertilizer recommendations. Also, an increase in soil health understanding has created the potential for soil health measurements to be used to improve the accuracy of these recommendations. The objectives for this study were to 1) evaluate the current P and K critical values and 2) determine the effect of including soil health indicators on improving fertilizer recommendation accuracy. This project was conducted throughout central and eastern SD from 2019-2021 …


Northern Great Plains Saline Sodic Soil Development, Classification, Remediation, And Management., Shaina Westhoff Jan 2022

Northern Great Plains Saline Sodic Soil Development, Classification, Remediation, And Management., Shaina Westhoff

Electronic Theses and Dissertations

Soil salinity and sodicity are issues of growing concern in the United States (U.S.) and globally. Knowledge gaps for glaciated, dryland salt-affected soils exist because much original salinity and sodicity research focused on irrigated systems. Land managers are being asked to produce food, feed, fiber, and fuel for an expanding global population. The number of land managers and crop advisors who are affected by these soils is increasing. Addressing salinity and sodicity knowledge gaps will be critical for their success. Salinity and sodicity have been impeding crop productivity since the advent of cultivation. Saline and sodic soils form via multiple …


The Times, They Are A-Changin': Tracking Shifts In Mental Health Signals From Early Phase To Later Phase Of The Covid-19 Pandemic In Australia, Siqin Wang, Xiao Huang, Tao Hu, Mengxi Zhang, Zhenlong Li, Huan Ning, Jonathan Corcoran, Asaduzzaman Khan, Yan Liu, Jiajia Zhang, Xiaoming Li Jan 2022

The Times, They Are A-Changin': Tracking Shifts In Mental Health Signals From Early Phase To Later Phase Of The Covid-19 Pandemic In Australia, Siqin Wang, Xiao Huang, Tao Hu, Mengxi Zhang, Zhenlong Li, Huan Ning, Jonathan Corcoran, Asaduzzaman Khan, Yan Liu, Jiajia Zhang, Xiaoming Li

Geosciences Faculty Publications and Presentations

Introduction Widespread problems of psychological distress have been observed in many countries following the outbreak of COVID-19, including Australia. What is lacking from current scholarship is a national-scale assessment that tracks the shifts in mental health during the pandemic timeline and across geographic contexts.

Methods Drawing on 244 406 geotagged tweets in Australia from 1 January 2020 to 31 May 2021, we employed machine learning and spatial mapping techniques to classify, measure and map changes in the Australian public’s mental health signals, and track their change across the different phases of the pandemic in eight Australian capital cities.

Results Australians’ …


Evaluating Essential Processes And Forecast Requirements For Meteotsunami-Induced Coastal Flooding, Chenfu Huang, Eric Anderson, Yi Liu, Gangfeng Ma, Greg Mann, Pengfei Xue Jan 2022

Evaluating Essential Processes And Forecast Requirements For Meteotsunami-Induced Coastal Flooding, Chenfu Huang, Eric Anderson, Yi Liu, Gangfeng Ma, Greg Mann, Pengfei Xue

Civil & Environmental Engineering Faculty Publications

Meteotsunamis pose a unique threat to coastal communities and often lead to damage of coastal infrastructure, deluge of nearby property, and loss of life and injury. The Great Lakes are a known hot-spot of meteotsunami activity and serve as an important region for investigation of essential hydrodynamic processes and model forecast requirements in meteotsunami-induced coastal flooding. For this work, we developed an advanced hydrodynamic model and evaluate key model attributes and dynamic processes, including: (1) coastal model grid resolution and wetting and drying process in low-lying zones, (2) coastal infrastructure, including breakwaters and associated submerging and overtopping processes, (3) annual/seasonal …


Dynamic Modeling Of Inland Flooding And Storm Surge On Coastal Cities Under Climate Change Scenarios: Transportation Infrastructure Impacts In Norfolk, Virginia Usa As A Case Study, Yawen Shen, Navid Tahvildari, Mohamed M. Morsy, Chris Huxley, T. Donna Chen, Jonathan Lee Goodall Jan 2022

Dynamic Modeling Of Inland Flooding And Storm Surge On Coastal Cities Under Climate Change Scenarios: Transportation Infrastructure Impacts In Norfolk, Virginia Usa As A Case Study, Yawen Shen, Navid Tahvildari, Mohamed M. Morsy, Chris Huxley, T. Donna Chen, Jonathan Lee Goodall

Civil & Environmental Engineering Faculty Publications

Low-lying coastal cities across the world are vulnerable to the combined impact of rainfall and storm tide. However, existing approaches lack the ability to model the combined effect of these flood mechanisms, especially under climate change and sea level rise (SLR). Thus, to increase flood resilience of coastal cities, modeling techniques to improve the understanding and prediction of the combined effect of these flood hazards are critical. To address this need, this study presents a modeling system for assessing the combined flood impact on coastal cities under selected future climate scenarios that leverages ocean modeling with land surface modeling capable …


Surface Morphologies In A Mars-Analog Ca-Sulfate Salar, High Andes, Northern Chile, Nancy W. Hinman, Michael H. Hofmann, Kimberly Warren-Rhodes, Michael S. Phillips, Nora Noffke, Nathalie A. Cabrol, Guillermo Chong Diaz, Cecilia Demergasso, Cinthya Tebes-Cayo, Oscar Cabestro, Janice L. Bishop, Virginia C. Gulick, David Summers, Pablo Sobron, Michael Mcinenly, Jeffrey Moersch, Constanza Rodriguez, Philippe Sarazzin, Kevin L. Rhodes, Camila Javiera Riffo Contreras, David Wettergreen, Victor Parro Jan 2022

Surface Morphologies In A Mars-Analog Ca-Sulfate Salar, High Andes, Northern Chile, Nancy W. Hinman, Michael H. Hofmann, Kimberly Warren-Rhodes, Michael S. Phillips, Nora Noffke, Nathalie A. Cabrol, Guillermo Chong Diaz, Cecilia Demergasso, Cinthya Tebes-Cayo, Oscar Cabestro, Janice L. Bishop, Virginia C. Gulick, David Summers, Pablo Sobron, Michael Mcinenly, Jeffrey Moersch, Constanza Rodriguez, Philippe Sarazzin, Kevin L. Rhodes, Camila Javiera Riffo Contreras, David Wettergreen, Victor Parro

OES Faculty Publications

Salar de Pajonales, a Ca-sulfate salt flat in the Chilean High Andes, showcases the type of polyextreme environment recognized as one of the best terrestrial analogs for early Mars because of its aridity, high solar irradiance, salinity, and oxidation. The surface of the salar represents a natural climate-transition experiment where contemporary lagoons transition into infrequently inundated areas, salt crusts, and lastly dry exposed paleoterraces. These surface features represent different evolutionary stages in the transition from previously wetter climatic conditions to much drier conditions today. These same stages closely mirror the climate transition on Mars from a wetter early Noachian to …


Evidence For Metabolic Diversity In Meso-Neoproterozoic Stromatolites (Vazante Group, Brazil), Flavia Callefo, Fresia Ricardi-Branco, Mirian Mírian Liza Alves Forancelli Pacheco, Alexandre Ribeiro Cardoso, Nora Noffke, Verônica De Carvalho Teixeira, Itamar Tomio Neckel, Lara Maldanis, Emma Bullock, Dina Bower, Adalene Moreira Silva, Dario Ferreira Sanchez, Fabio Rodrigues, Douglas Galante Jan 2022

Evidence For Metabolic Diversity In Meso-Neoproterozoic Stromatolites (Vazante Group, Brazil), Flavia Callefo, Fresia Ricardi-Branco, Mirian Mírian Liza Alves Forancelli Pacheco, Alexandre Ribeiro Cardoso, Nora Noffke, Verônica De Carvalho Teixeira, Itamar Tomio Neckel, Lara Maldanis, Emma Bullock, Dina Bower, Adalene Moreira Silva, Dario Ferreira Sanchez, Fabio Rodrigues, Douglas Galante

OES Faculty Publications

Deciphering the evolution of ecological interactions among the metabolic types during the early diversification of life on Earth is crucial for our understanding of the ancient biosphere. The stromatolites from the genus Conophyton cylindricus represent a datum for the Proterozoic (Meso to Neoproterozoic) on Earth. Their typical conical shape has been considered a result of a competition between microorganisms for space, light and nutrients. Well-preserved records of this genus from the "Paleontological Site of Cabeludo ", Vazante Group, São Francisco Craton (Southern Brazil) present in situ fossilized biofilms, containing preserved carbonaceous matter. Petrographic and geochemical analyses revealed an alternation between …


Present And Future Thermal Regimes Of Intertidal Groundwater Springs In A Threatened Coastal Ecosystem, Jason J. Karrisallen, Aaron A. Mohammed, Joseph Tamborski, Rob C. Jamieson, Serban Danielescu, Barret L. Kurylyk Jan 2022

Present And Future Thermal Regimes Of Intertidal Groundwater Springs In A Threatened Coastal Ecosystem, Jason J. Karrisallen, Aaron A. Mohammed, Joseph Tamborski, Rob C. Jamieson, Serban Danielescu, Barret L. Kurylyk

OES Faculty Publications

In inland settings, groundwater discharge thermally modulates receiving surface water bodies and provides localized thermal refuges; however, the thermal influence of intertidal springs on coastal waters and their thermal sensitivity to climate change are not well studied. We addressed this knowledge gap with a field- and model-based study of a threatened coastal lagoon ecosystem in southeastern Canada. We paired analyses of drone-based thermal imagery with in situ thermal and hydrologic monitoring to estimate discharge to the lagoon from intertidal springs and groundwater-dominated streams in summer 2020. Results, which were generally supported by independent radon-based groundwater discharge estimates, revealed that combined …


Editorial: Carbon Cycling In Aquatic Critical Zones, Peng Yao, Thomas S. Bianchi, David J. Burdige, Xiaojuan Feng, Peter A. Raymond Jan 2022

Editorial: Carbon Cycling In Aquatic Critical Zones, Peng Yao, Thomas S. Bianchi, David J. Burdige, Xiaojuan Feng, Peter A. Raymond

OES Faculty Publications

No abstract provided.


Sediment Mineralogy Influences The Rate Of Microbial Sulfate Reduction In Marine Sediments, Chin Yik Lin, Harold J. Bradbury, Gilad Antler, David J. Burdige, Thomas D. Bennett, Shichun Li, Alexandra V. Turchyn Jan 2022

Sediment Mineralogy Influences The Rate Of Microbial Sulfate Reduction In Marine Sediments, Chin Yik Lin, Harold J. Bradbury, Gilad Antler, David J. Burdige, Thomas D. Bennett, Shichun Li, Alexandra V. Turchyn

OES Faculty Publications

Sedimentary microbial communities play a critical role in the global carbon cycle, oxidizing deposited organic carbon and thus influencing the type of carbon buried from Earth's surface. The rate of microbial metabolism within sedimentary microbial communities is often linked to the lability and amount of organic carbon deposited. Here we show that, in pure culture, for sulfate-reducing bacteria (Desulfovibrio bizertensis) the rate of microbial sulfate reduction is a function of the proportion of clay minerals present in the incubation vials. We argue that the presence of clay minerals stimulates the growth of the sulfate-reducing bacteria and the rate …


Biofilm Harvesters In Coastal Settings Of The Early Palaeozoic, Nora Noffke, M. Gabriela Mángano, Luis A. Buatois Jan 2022

Biofilm Harvesters In Coastal Settings Of The Early Palaeozoic, Nora Noffke, M. Gabriela Mángano, Luis A. Buatois

OES Faculty Publications

The ichnogenera Syringomorpha and Daedalus are here interpreted as products of infaunal biofilm harvesters. This study investigated: (1) Syringomorpha nilssoni and Syringomorpha isp. from the Cambrian Series 2‐Miaolingian Campanario Formation, northwest Argentina; and (2) Daedalus halli from the Floian Grès et Schistes de la Cluse de l’Orb Formation, Montagne Noire, France. Syringomorpha nilssoni occurs in sandy to mixed intertidal to lower shoreface deposits, whereas Syringomorpha isp. in the lower intertidal zone. Daedalus halli occurs in a lagoon and intertidal to lower shoreface sands of a barrier island. Syringomorpha and Daedalus comprise a vertical J‐shaped causative burrow and deep spreite. These …


Seasonal Dynamics Of Dissolved Iron On The Antarctic Continental Shelf: Late-Fall Observations From The Terra Nova Bay And Ross Ice Shelf Polynyas, P. N. Sedwick, B. M. Sohst, C. O'Hara, S. E. Stammerjohn, B. Loose, M. S. Dinniman, N. J. Buck, J. A. Resing, S. F. Ackley Jan 2022

Seasonal Dynamics Of Dissolved Iron On The Antarctic Continental Shelf: Late-Fall Observations From The Terra Nova Bay And Ross Ice Shelf Polynyas, P. N. Sedwick, B. M. Sohst, C. O'Hara, S. E. Stammerjohn, B. Loose, M. S. Dinniman, N. J. Buck, J. A. Resing, S. F. Ackley

OES Faculty Publications

Over the Ross Sea shelf, annual primary production is limited by dissolved iron (DFe) supply. Here, a major source of DFe to surface waters is thought to be vertical resupply from the benthos, which is assumed most prevalent during winter months when katabatic winds drive sea ice formation and convective overturn in coastal polynyas, although the impact of these processes on water-column DFe distributions has not been previously documented. We collected hydrographic data and water-column samples for trace metals analysis in the Terra Nova Bay and Ross Ice Shelf polynyas during April-May 2017 (late austral fall). In the Terra Nova …


Ooi Biogeochemical Sensor Data: Best Practices And User Guide. Version 1.0.0., Hilary I. Palevsky, Sophie Clayton, Dariia Atamanchuk, Roman Battisti, Jennifer Batryn, Annie Bourbonnais, Ellen M. Briggs, Filipa Carvalho, Alison P. Chase, Rachel Eveleth, Rob Fatland, Kristen E. Fogaren, Jonathan Peter Fram, Susan E. Hartman, Isabela Le Bras, Cara C.M. Manning, Joseph A. Needoba, Merrie Beth Neely, Hilde Oliver, Andrew C. Reed, Jennie E. Rheuban, Christina Schallenberg, Michael F. Vardaro, Ian Walsh, Christopher Wingard Jan 2022

Ooi Biogeochemical Sensor Data: Best Practices And User Guide. Version 1.0.0., Hilary I. Palevsky, Sophie Clayton, Dariia Atamanchuk, Roman Battisti, Jennifer Batryn, Annie Bourbonnais, Ellen M. Briggs, Filipa Carvalho, Alison P. Chase, Rachel Eveleth, Rob Fatland, Kristen E. Fogaren, Jonathan Peter Fram, Susan E. Hartman, Isabela Le Bras, Cara C.M. Manning, Joseph A. Needoba, Merrie Beth Neely, Hilde Oliver, Andrew C. Reed, Jennie E. Rheuban, Christina Schallenberg, Michael F. Vardaro, Ian Walsh, Christopher Wingard

OES Faculty Publications

The OOI Biogeochemical Sensor Data Best Practices and User Guide is intended to provide current and prospective users of data generated by biogeochemical sensors deployed on the Ocean Observatories Initiative (OOI) arrays with the information and guidance needed for them to ensure that the data is science-ready. This guide is aimed at researchers with an interest or some experience in ocean biogeochemical processes. We expect that users of this guide will have some background in oceanography, however we do not assume any prior experience working with biogeochemical sensors or their data. While initially envisioned as a “cookbook” for end users …


Insights Into The Deglacial Variability Of Phytoplankton Community Structure In The Eastern Equatorial Pacific Ocean Using [231Pa/230Th]Xs And Opal-Carbonate Fluxes, Danielle Schimmenti, Franco Marcantonio, Christopher T. Hayes, Jennifer Hertzberg, Matthew Schmidt, John Sarao Jan 2022

Insights Into The Deglacial Variability Of Phytoplankton Community Structure In The Eastern Equatorial Pacific Ocean Using [231Pa/230Th]Xs And Opal-Carbonate Fluxes, Danielle Schimmenti, Franco Marcantonio, Christopher T. Hayes, Jennifer Hertzberg, Matthew Schmidt, John Sarao

OES Faculty Publications

Fully and accurately reconstructing changes in oceanic productivity and carbon export and their controls is critical to determining the efficiency of the biological pump and its role in the global carbon cycle through time, particularly in modern CO2 source regions like the eastern equatorial Pacific (EEP). Here we present new high-resolution records of sedimentary 230Th-normalized opal and nannofossil carbonate fluxes and [231Pa/230Th]xs ratios from site MV1014-02-17JC in the Panama Basin. We find that, across the last deglaciation, phytoplankton community structure is driven by changing patterns of nutrient (nitrate, iron, and silica) availability which, in …


Changing Snowmelt Conditions In The Western Canadian Arctic, Matthew Y. T. Tsui Jan 2022

Changing Snowmelt Conditions In The Western Canadian Arctic, Matthew Y. T. Tsui

Theses and Dissertations (Comprehensive)

Multidecadal Changes in Spring Snowmelt in the Western Canadian Arctic

This study investigates the changes in key aspects of snowmelt in the western Canadian Arctic. Specifically, we will look at changes in the onset of snowmelt and the duration of snowmelt between 1999 and 2019, and extended air temperature between 1957 and 2019. In addition, we will look at changes in eight meteorological variables during the melt period. It was found that the onset of snowmelt occurred 14 days earlier, while the melt period ends 20 days earlier than 20 years ago. As a result, the duration of melt period …


Lake Huron Shoreline Analysis, Shubham Satish Nandanwar Jan 2022

Lake Huron Shoreline Analysis, Shubham Satish Nandanwar

Theses and Dissertations (Comprehensive)

Lake Huron is a popular tourist destination and is home to several businesses and residents. Since the shoreline is dynamic and is subject to change over the years due to several factors such as a change in water level, soil type, human encroachment, etc., these locations tend to encounter floods due to increased water levels and wind speed. This causes erosion and loss to the properties along the shoreline.

This study is based on two areas of interest named Pinery Provincial Park and Sauble Beach which are located on the shoreline of Lake Huron where Pinery Provincial Park is a …


The Kanarra Fold-Thrust System -- The Leading Edge Of The Sevier Fold-Thrust Belt, Southwest Utah, William Joseph Michael Chandonia Jan 2022

The Kanarra Fold-Thrust System -- The Leading Edge Of The Sevier Fold-Thrust Belt, Southwest Utah, William Joseph Michael Chandonia

Doctoral Dissertations

“The Jurassic to Eocene Sevier fold-thrust belt is the subject of continued scientific curiosity in tectonics, stratigraphy, and industry. Understanding its development in southwest Utah is hindered in part due to the multiple origins proposed for the Kanarra anticline, a major leading edge structure -- a drag fold along the Hurricane fault, Laramide monocline, Sevier fault propagation fold, or a combination of these -- which have confused its tectonic significance and regional context. This confusion results from the structural complexity of its exposed eastern limb, as well as displacement and burial of its crest and western limb beneath Neogene sediments …


Biotic Characteristics Of Managed And Unmanaged Coastal Dunes In The Outer Banks, North Carolina, Andrew E. White Jan 2022

Biotic Characteristics Of Managed And Unmanaged Coastal Dunes In The Outer Banks, North Carolina, Andrew E. White

Theses and Dissertations

Under future climate change and sea level rise scenarios, Natural and Nature-Based Features (e.g., dunes) that protect coastal habitat and infrastructure will be exposed to increased wave energy and storm surge. Understanding how these forces will impact coastal dunes is necessary for their continued use as protective features. Coastal dunes develop through feedback between vegetation and sediment deposition, a process complicated by species-specific growth rates and responses to burial. Wave flume studies have tested the effects of dune vegetation on erosion and found multiple plant organs across several functional types to be important for resisting erosion. Although dune building and …


Using Lake Sediment Chemistry In The Exploration For Nickel Laterite Deposits In Tropical Regions, Gabriela Yvonne Ramirez Jan 2022

Using Lake Sediment Chemistry In The Exploration For Nickel Laterite Deposits In Tropical Regions, Gabriela Yvonne Ramirez

Masters Theses

"Developing reliable geochemical indicators to guide the search for ore deposits is a long-standing goal. This particularly applies to tropical regions that are often heavily vegetated which hampers boots-on-the ground exploration efforts. Here we present the preliminary results of a study that investigates the usefulness of lake sediment chemistry in the exploration for nickel laterite ore deposits in tropical regions using Lake Izabal, Guatemala, as a case study. Lake Izabal’s catchment area contains Ni laterite deposits along its northern shore, whereas no Ni-laterite discoveries have been made in the south except for a Ni mine in the southern region that …


Adsorption Of Arsenic Onto River Sediments, Leticia Augusta Dos Santos Ferreira Jan 2022

Adsorption Of Arsenic Onto River Sediments, Leticia Augusta Dos Santos Ferreira

Masters Theses

“Previous studies have noted the relationship between shallow groundwater rich in sodium (Na) and bicarbonate (HCO3) and elevated levels of dissolved arsenic. However, most experimental work on arsenic adsorption in the presence of HCO3 and differing Na/Ca ratios has proven difficult to extrapolate to natural systems because of differences in tested mineral compositions and component concentrations. In this study, I performed a series of adsorption experiments using river sediments to evaluate the influence of HCO3 and monovalent/divalent cations on the extent of arsenic adsorption onto natural sediment in groundwater.

Batch adsorption (kinetics, equilibrium, and metal loading) …


Pressure Relief Wells: Analysis Of Subsurface Heterogeneity To Evaluate Relief Well Locations For Mississippi River Levees, Emma Marie Young Jan 2022

Pressure Relief Wells: Analysis Of Subsurface Heterogeneity To Evaluate Relief Well Locations For Mississippi River Levees, Emma Marie Young

Masters Theses

“When designing pressure relief well systems, it is imperative to understand what major geomorphology and heterogenies features are present, such as buried oxbow lakes, especially when the feature is parallel to the source, such as the Mississippi River. When present, there is a notable greater increase in head pressures, especially on the landward tow of the levee. This can cause erosional features that originally thought of to have been protected from by installing pressure relief wells. When comparing the effective hydraulic conductivities of horizontal clay layers and vertical clay layers spanning the length of the model, little to no noticeable …


Laterally Heterogeneous Seismic Anisotropy Investigated By Shear Wave Splitting Analyses, Yan Jia Jan 2022

Laterally Heterogeneous Seismic Anisotropy Investigated By Shear Wave Splitting Analyses, Yan Jia

Doctoral Dissertations

"Numerous geophysical studies suggest that seismic anisotropy is a nearly ubiquitous property of the Earth’s crust and upper mantle. In this study, we utilize the shear wave splitting technique to investigate the piercing-point-dependent azimuthal anisotropy beneath the northeastern edge of the Sichuan Basin in central China, and the spatial and temporal variations of anisotropy near the 2019 M7.1 Ridgecrest earthquake in California, respectively. A clear back azimuthal dependence of the splitting parameters and the lack of a 90° or 180° periodicity of azimuthal variation in the observed fast orientations provide strong evidence for the existence of piercing-point-dependent anisotropy beneath the …


Mantle Flow And Transition Zone Discontinuities Beneath The Carribean Plate: Constraints From Shear Wave Splitting And Receiver Function Analyses, Tu Xue Jan 2022

Mantle Flow And Transition Zone Discontinuities Beneath The Carribean Plate: Constraints From Shear Wave Splitting And Receiver Function Analyses, Tu Xue

Doctoral Dissertations

"Azimuthal anisotropy quantified by teleseismic SKS, SKKS, PKS (“XKS”) and local S wave splitting parameters is used to investigate lithospheric deformation and asthenospheric flow beneath the boundary zone of the North American and Caribbean plates and adjacent areas. A total of 4915 XKS and 1202 pairs of local S wave splitting parameters were obtained at 24 broad band seismic stations. The XKS observations can be divided into two groups based on the spatial distribution of the resulting fast polarization orientations. Those observed on the Caribbean Plate are mostly WNW-ESE which are roughly trench-parallel. In contrast, the fast orientations observed on …


Depositional Conditions, Stratigraphic Evolution, And Allo- And Autogenic Controls Of Lower Permian Non-Marine Carbonate Rocks, Lucaogou Low-Order Cycle, Bogda Mountains, Nw China, Yiran Lu Jan 2022

Depositional Conditions, Stratigraphic Evolution, And Allo- And Autogenic Controls Of Lower Permian Non-Marine Carbonate Rocks, Lucaogou Low-Order Cycle, Bogda Mountains, Nw China, Yiran Lu

Doctoral Dissertations

"The overall objective of this study is to interpret the depositional conditions of lacustrine carbonate deposits of the lower Permian Lucaogou low-order cycle in the greater Turpan-Junggar continental rift basin, NW China. The depositional environments of ten carbonate lithofacies in the Tarlong-Taodonggou half graben and the Zhaobishan section were interpreted. Allo- and autogenic factors were identified. They controlled characteristics and distribution pattern of carbonate deposits in regional and local scale, respectively. Allogenic factors include the amount and direction of regional siliciclastic input, basin geometry, cyclic humidity/aridity oscillation, temperature, and regional tectonics. Autogenic factors include local siliciclastic input, local topography, local …


Application Of Machine Learning In Geophysics: Ranking Teleseismic Shear Wave Splitting Measurements And Classifying Different Types Of Earthquakes, Yanwei Zhang Jan 2022

Application Of Machine Learning In Geophysics: Ranking Teleseismic Shear Wave Splitting Measurements And Classifying Different Types Of Earthquakes, Yanwei Zhang

Doctoral Dissertations

"During the past decades, applications of Machine Learning have been explosively developed to solve various academic and industrial problems, and over-human performance has been shown in diverse areas. In geophysical research, Machine Learning, especially Convolutional Neural Network (CNN), has been applied in numerous studies and demonstrated considerable potential. In this study, we applied CNN to solve two geophysical problems, ranking teleseismic shear splitting (SWS) measurements and classifying different types of earthquakes.

For ranking teleseismic SWS measurements, we utilized a CNN-based method to automatically select reliable SWS measurements. The CNN was trained by human-verified teleseismic SWS measurements and tested using synthetic …


Re-Crosslinking Particle Gel For Co2 Compliance Control And Co2 Filtration Blocking, Yifu Long, Baojun Bai, Thomas P. Schuman Jan 2022

Re-Crosslinking Particle Gel For Co2 Compliance Control And Co2 Filtration Blocking, Yifu Long, Baojun Bai, Thomas P. Schuman

Patents

The present invention generally relates to the composition of particle gels for CO2 - EOR and CO2 storage . More particularly , CO2 resistant particle gels are provided that can re - crosslink at subterranean conditions . These particle gels can be deployed to improve the conformance of CO , flooding , CO , huff - puff , or Water - Alternative - Gas ( WAG ) . The applications may also involve CO2 storage , such as the blocking of CO2 leakage and similar CO2 processing .


Potential Of Entomocomposting Toward Soil Pathogen Suppression, Dennis Beesigamukama, María Gómez-Brandón, Chrysantus Mbi Tanga Jan 2022

Potential Of Entomocomposting Toward Soil Pathogen Suppression, Dennis Beesigamukama, María Gómez-Brandón, Chrysantus Mbi Tanga

All Peer-Reviewed Publications

Waste accumulation and microbial pollution are key environmental challenges in most developing countries. Land filling, the commonest waste disposal method, is not sustainable due to land scarcity and point source pollution. Thus, a large fraction of organic wastes is not properly disposed, yet the conventional methods of waste recycling are less effective. The degradation of waste using insect life stages (entomocomposting) has emerged as a novel tool that is fast, affordable, and sustainable in recycling organic wastes with maximum pathogen suppression. This bioconversion process also generates an organic fertilizer with potential to enhance soil remediation and provide additional benefits on …


Fiber Assisted Re-Cross-Linkable Polymer Gel And Preformed Particle Gels For Fluid Loss And Conformance Control, Baojun Bai, Ze Wang, Zhe Sun, Jingyang Pu, Thomas P. Schuman Jan 2022

Fiber Assisted Re-Cross-Linkable Polymer Gel And Preformed Particle Gels For Fluid Loss And Conformance Control, Baojun Bai, Ze Wang, Zhe Sun, Jingyang Pu, Thomas P. Schuman

Patents

Described herein are compositions useful for controlling fluid flow, for example in a target zone of a subterranean environment, and methods of forming and using the same. The composition generally comprises a quantity of fibers and a quantity of swellable particles, which may be dispersed in a carrier fluid. The composition may be synthesized in the form of a bulk gel or may be gelatinated during use. The fibers in the compositions provide improved performance as compared to prior PPG and RPPG particle containing compositions. Specifically, the compositions reinforce the re-cross-linked/re-associated hydrogel plug in underground features and support proper rehydration …