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Articles 3151 - 3169 of 3169
Full-Text Articles in Earth Sciences
Measuring And Modeling Riparian Wetland Saturated Hydraulic Conductivity, Nutrient Concentrations And Shallow Groundwater Dynamics In An Appalachian Mixed Land Use Catchment, Bidisha Faruque Abesh
Measuring And Modeling Riparian Wetland Saturated Hydraulic Conductivity, Nutrient Concentrations And Shallow Groundwater Dynamics In An Appalachian Mixed Land Use Catchment, Bidisha Faruque Abesh
Graduate Theses, Dissertations, and Problem Reports (ETD)
The paucity of research on accurate predictions of saturated hydraulic conductivity (Ksat), spatiotemporal analysis of nutrient concentrations relative to water source types (stream and shallow groundwater (SGW)), water flow directions, and land use in riparian wetlands of Appalachian mixed land use catchments underscored the need for this study. Additionally, the lack of SGW flow simulations and stream-SGW interactions using three-dimensional (3D) numerical models (i.e., MODFLOW) in these riparian wetlands further highlighted the research gap. Observed data including soil properties, Ksat, surface water (SW) and SGW levels, and nutrient concentrations, including nitrate (NO3-N), nitrite (NO2-N), ammonium (NH4-N), orthophosphate (PO43-P), total nitrogen …
Fluid-Rock And Fluid-Steel Interaction In Geothermal Energy Development In The Appalachain Basin, Samuel H. Bowman
Fluid-Rock And Fluid-Steel Interaction In Geothermal Energy Development In The Appalachain Basin, Samuel H. Bowman
Graduate Theses, Dissertations, and Problem Reports (ETD)
The ever-increasing demand for clean energy requires creative solutions. In the United States, unconventional energy sources such as geothermal are conventionally limited to the western half of the country. The Appalachian Basin in the Eastern United States is one such possible creative solution, although the comparatively low temperature gradient presents a significant challenge to delivering economically feasible geothermal energy. An emerging technology is enhanced geothermal systems, these are engineered reservoirs where a working fluid (typically water) is cycled between the subsurface energy source and the energy collection facility at the surface. The liquid water interacts with the geothermal reservoir rock …
Identifying And Predicting Patterns Of Snowpack Ripening With Machine Learning Methods, Clement Cherblanc
Identifying And Predicting Patterns Of Snowpack Ripening With Machine Learning Methods, Clement Cherblanc
Graduate Student Theses, Dissertations, & Professional Papers
The timing of water release from the snowpack plays key roles in ecosystem services, groundwater recharge, and water resource management. However, two internal barriers in a standing snowpack must be overcome before runoff can outflow from the base: 1) the cold content must be exhausted, and 2) the interconnected network of snow grains must be filled with liquid water to residual saturation. Expressing the liquid water as latent heat allows the two barriers to be grouped as an energy (J/m²) to define a snowpack’s Runoff Energy Hurdle (REH). The growth and loss of REH is driven by evolution of pore …
Experimental Investigation Of High-Temperature Brine-Shale Interactions, Anna Atasha Hoffmann
Experimental Investigation Of High-Temperature Brine-Shale Interactions, Anna Atasha Hoffmann
Doctoral Dissertations
"Hydrofracturing (fracking), a common practice in the Petroleum Industry to induce or improve fluid flow in tight formations, creates chemical disequilibrium that further alters the porosity and permeability of host rocks and results in the production of saline and contaminated produced waters (PW). The PW of the Tuscaloosa Marine Shale (TMS) are Na-Ca-Mg-K-Cl brines with mean concentrations of approximately 16% Total Dissolved Solids (TDS) and circumneutral pH. Analysis of composition suggests the PW result from a 20 to 80% dilution of formation waters (relict brines of the Louann Salt) by fracking fluid. Trace element concentrations generally show moderate to strong …
Coupling-Informed Data-Driven Scheme For Joint Angle And Frequency Estimation In Uniform Linear Array With Mutual Coupling Present, Yanming Zhang, Wenchao Xu, A. Long Jin, Min Li, Peifeng Ma, Lijun Jiang, Steven Gao
Coupling-Informed Data-Driven Scheme For Joint Angle And Frequency Estimation In Uniform Linear Array With Mutual Coupling Present, Yanming Zhang, Wenchao Xu, A. Long Jin, Min Li, Peifeng Ma, Lijun Jiang, Steven Gao
Electrical and Computer Engineering Faculty Research & Creative Works
This paper proposes a novel coupling-informed data-driven algorithm tailored for the concurrent estimation of frequency and angle within a uniform linear array (ULA), while addressing the complicating influence of mutual coupling. Leveraging the hybrid dynamic mode decomposition (DMD) methodology, termed as averaged DMD, we incorporate moving average techniques to achieve effective denoising. The averaged DMD further decomposes the received signal into eigenvalues and corresponding eigenvectors. The frequency information is derived from the eigenvalues and the corresponding eigenvectors represent the steering vectors of sources. Subsequently, mutual coupling is informed into the calibration of the steering vector for each source. Specifically, the …
A Tensor-Based Data-Driven Approach For Multidimensional Harmonic Retrieval And Its Application For Mimo Channel Sounding., Yanming Zhang, Wenchao Xu, A. Long Jin, Min Li, Ping Yuan, Lijun Jiang, Steven Gao
A Tensor-Based Data-Driven Approach For Multidimensional Harmonic Retrieval And Its Application For Mimo Channel Sounding., Yanming Zhang, Wenchao Xu, A. Long Jin, Min Li, Ping Yuan, Lijun Jiang, Steven Gao
Electrical and Computer Engineering Faculty Research & Creative Works
In wireless channel sounding, accurately estimating multiple parameters within a multipath signal, such as azimuth, elevation, Doppler shift, and delay, necessitates addressing the challenges posed by the multidimensional harmonic retrieval (MHR) problem. To overcome these complexities, we propose a framework based on high-order dynamic mode decomposition (HODMD) that designed for robustly estimating frequencies of interest from high-dimensional sinusoidal signals, particularly in additive white Gaussian noise conditions. The HODMD approach, a hybrid algorithm amalgamating high-order singular value decomposition (HOSVD) and dynamic mode decomposition (DMD), operates by initially decomposing observed tensorial data into a core tensor and R mode matrices through HOSVD. …
Portable X-Ray Fluorescence Spectrometry For Sensing Salinity And Sodicity In Glacial Northern Great Plains Soils With Machine Learning Models, Adam Devlin
Electronic Theses and Dissertations
Saline and sodic soils are an increasing concern across the Northern Great Plains (NGP) due to factors of climate change and land management that are drawing geologically derived salts to the land surface. Traditional laboratory assessments, such as electrical conductivity (EC) and sodium adsorption ratio (SAR), are time and resource consumptive. Portable X-ray fluorescence (PXRF) may be a viable proximal sensing alternative, as it is able to provide elemental data in minutes, in situ or ex situ, and can directly quantify salinity-associated elements like Ca, Mg, and S. PXRF paired with predictive models has proven useful for a range of …
Impacts Of Cover Crops And Diversified Crop Rotations On Soil Biochemical Properties, Hydrophysical Characteristics, And Water Dynamics In Long-Term No-Till Cropping Systems, Sainfort Vital
Electronic Theses and Dissertations
This research assessed the impacts of crop rotations and cover crops on the soil's biochemical and hydrophysical properties within long-term no-till systems. The research was conducted at the Southeast Research Farm, near Beresford, South Dakota. The crop rotations contain two levels: 4-year corn (Zea mays L.)-soybean (Glycine max L.)-oat (Avena sativa L.)-rye (Secale cereale L.) (CSOR) and 2-year corn-soybean (CS) rotations. The cover crop factors also had two levels within each rotation treatment: cover crops (CC) and no cover crops (NCC). All plots were managed under long-term no-till (NT), with soils mapped as Egan silty clay loam (fine-silty, mixed, superactive, …
Trace And Rare Earth Elements Analysis Of Oligocene And Miocene Diamictites In The Cape Roberts Project, Ross Sea, Antarctica, Celina Flores Garza
Trace And Rare Earth Elements Analysis Of Oligocene And Miocene Diamictites In The Cape Roberts Project, Ross Sea, Antarctica, Celina Flores Garza
Theses, Dissertations and Culminating Projects
The West Antarctic Ice Sheet is a major contributor to global sea level rise, yet its origin and dynamics are poorly known. The geochemistry of 35 diamictite samples from the CRP-1 and CPR-2A cores recovered by the Cape Roberts Drilling Project in the Ross Sea, Antarctica is evaluated to understand glacial sedimentation and flow paths during the Oligocene and Miocene, a period of warmer than present climate in the past. The major hypothesis to be tested is if the early Miocene ice sheet advance was the first major West Antarctic ice advance in the Ross Sea. The provenance of older …
Assessing And Understanding Soil Characteristics, Amy Papineau
Assessing And Understanding Soil Characteristics, Amy Papineau
UNH Cooperative Extension
No abstract provided.
Storm-Generated Molluscan Thanatocoenosis Along A Carbonate Paleoshoreline: Southern Eleuthera Island, The Bahamas, Ilya Val Buynevich, Michael Savarese, H. Allen Curran, Tara Ingalsbe
Storm-Generated Molluscan Thanatocoenosis Along A Carbonate Paleoshoreline: Southern Eleuthera Island, The Bahamas, Ilya Val Buynevich, Michael Savarese, H. Allen Curran, Tara Ingalsbe
Geosciences: Faculty Publications
Concentrations of large mollusc shells in coastal deposits provide important information about the local malacofauna and potential transport agents, including extreme events [1-4]. Such accumulations are common in the rock record [5,6], with Quaternary examples serving as good time-averaged examples by combining aspects of both the modern biocoenoses and the fossil record. Death assemblages of local organisms (thanatocoenosis) and their preserved record (taphocoenosis) in carbonate settings, where granulometric spectrum may be very limited (e.g., ooilitic sand), can serve as important paleo-environmental indicators, especially when considered in combination with primary sedimentary structures (in outcrops or geophysical images) and in situ biogenic …
A New Method To Invert For Interseismic Deep Slip Along Closely Spaced Faults Using Surface Velocities And Subsurface Stressing-Rate Tensors, Hanna Elston, Michele Cooke, John Loveless, Scott Marshall
A New Method To Invert For Interseismic Deep Slip Along Closely Spaced Faults Using Surface Velocities And Subsurface Stressing-Rate Tensors, Hanna Elston, Michele Cooke, John Loveless, Scott Marshall
Geosciences: Faculty Publications
Inversions of interseismic geodetic surface velocities often cannot uniquely resolve the three-dimensional slip-rate distribution along closely spaced faults. Microseismic focal mechanisms reveal stress information at depth and may provide additional constraints for inversions that estimate slip rates. Here, we present a new inverse approach that utilizes both surface velocities and subsurface stressing-rate tensors to constrain interseismic slip rates and activity of closely spaced faults. We assess the ability of the inverse approach to recover slip rate distributions from stressing-rate tensors and surface velocities generated by two forward models: (a) a single strike-slip fault model and (b) a complex southern San …
Diagenesis And Quartz Grain Provenance Of The Turner Sandstone, Carson Lee Broaddus
Diagenesis And Quartz Grain Provenance Of The Turner Sandstone, Carson Lee Broaddus
Graduate Student Theses, Dissertations, & Professional Papers
Provenance analysis of sedimentary rocks is an essential tool for basin analysis and paleogeographic reconstructions. Numerous tools and analytical methods have been developed over the years to investigate the source of detrital constituents in sedimentary rocks. The Late Cretaceous (Turonian) Turner Sandstone in the eastern Powder River Basin (PRB), WY, and the time equivalent Frontier Formation in the western PRB are commonly described as the remnants of a marginal marine depositional system. However, contradictory evidence exists about the source of those deposits. Here, I present results from a comprehensive scanning electron microscope panchromatic cathodoluminescence (SEM-PCL) analysis of >1200 individual sand-sized …
Paragenesis Of The Austin Chalk Formation In Southwest Texas, Mitchell C. Sherry
Paragenesis Of The Austin Chalk Formation In Southwest Texas, Mitchell C. Sherry
Graduate Student Theses, Dissertations, & Professional Papers
Presented in this study is a detailed investigation of the paragenesis and diagenetic processes of the Austin Chalk Formation in southwest Texas, utilizing a combination of core-based, petrographic, mineralogic, SEM, and geochemical based analyses. This study is conducted on a single whole rock core from an oil and gas producing well in Webb County, Texas. At this distal shelf location within the Maverick Basin, the Austin Chalk Formation consists of foraminiferal wackestones, siliceous wackestones, foraminiferal mudstones, bentonites, and foraminiferal packstone facies. These facies were deposited below wave base through pelagic, hemipelagic, and gravity driven processes. Petrographic and SEM analyses reveal …
A Soil-Plant-Atmosphere Continuum Model To Simulate Seedling Response To Water Stress, Michael Kurt Kendree Jr.
A Soil-Plant-Atmosphere Continuum Model To Simulate Seedling Response To Water Stress, Michael Kurt Kendree Jr.
Graduate Student Theses, Dissertations, & Professional Papers
Most current ecohydrologic models simplify the hydraulics that are at play in plant-water relationships by assuming that the water content within the plant is static. In reality, plants have a relative water content that varies with time in response to environmental stresses. To some extent, variations in plant relative water content are regulated by changes in the osmotic potential of water within plant cells, which contributes to the resilience of plants during periods of water shortage. We present a model that simulates plant water transport and storage within the soil-plant-atmosphere continuum. The model incorporates the role of osmotic regulation in …
From Creek To Ditch And Back Again: The History And Future Of Pattee Creek, Missoula, Montana, Carver Edward Butterfield
From Creek To Ditch And Back Again: The History And Future Of Pattee Creek, Missoula, Montana, Carver Edward Butterfield
Graduate Student Theses, Dissertations, & Professional Papers
Pattee Creek was once a free-flowing stream that meandered across the Missoula Valley, but has been channelized, piped, and degraded by logging, mining, agriculture, and urbanization. This thesis used a mixed-method approach to examine the impact of human activities on the Pattee Creek watershed. Beginning with a historical overview, the story of how the creek has been utilized and why it was buried was told. An analysis of historical photos from 1937 to 2019 revealed drastic changes in the land cover of the watershed and the channel of lower Pattee Creek. Developed land increased dramatically, while open land decreased and …
Temporal And Spatial Connectivity And The Impacts Of Hydropower In The Magdalena River Basin, Colombia, Serena Lynn Butler
Temporal And Spatial Connectivity And The Impacts Of Hydropower In The Magdalena River Basin, Colombia, Serena Lynn Butler
Graduate Student Theses, Dissertations, & Professional Papers
Tropical regions hold untapped hydropower potential, but dam construction often adversely impacts multiple dimensions of connectivity in river systems, rigorous evaluation of which is often lacking. This study investigates temporal and spatial dimensions of longitudinal and lateral connectivity in the Magdalena River Basin, Colombia, a region with ongoing and planned hydropower projects. Limited in-situ monitoring data is a common challenge in tropical rivers. To address this, we utilized satellite imagery from Landsat (via Google Earth Engine) and Surface Water and Ocean Topography (SWOT) data. We examined alterations in the flow regime over time and relative to dam construction. We also …
Building Detailed And Accurate Whole-Plant Concepts: A Morphometrics-Informed Reconstruction Of A Zosterophyll From The Lower Devonian Of Wyoming, Samar R. El-Abdallah
Building Detailed And Accurate Whole-Plant Concepts: A Morphometrics-Informed Reconstruction Of A Zosterophyll From The Lower Devonian Of Wyoming, Samar R. El-Abdallah
Cal Poly Humboldt theses and projects
The fragmentary state of plant fossils and the modular organization of plants make whole-plant reconstructions of fossil species desirable and feasible. Such reconstructions are key for integrating fossil species in systematic studies. The ca. 410 Ma Beartooth Butte Formation of Wyoming (USA) hosts the only rich Early Devonian plant assemblages in western North America, which fills a major gap in the phytogeography of this interval. I construct a whole-plant concept for a new zosterophyll from the Beartooth Butte Formation based on a detailed morphometric study. More than 600 fragments of the new zosterophyll were observed and 200 of those were …
Modeling Apparent Pb Loss In Zircon U-Pb Geochronology, Glenn R. Sharman, Matthew A. Malkowski
Modeling Apparent Pb Loss In Zircon U-Pb Geochronology, Glenn R. Sharman, Matthew A. Malkowski
Geosciences Faculty Publications and Presentations
The loss of radiogenic Pb from zircon is known to be a major factor that can cause inaccuracy in the U–Pb geochronological system; hence, there is a need to better characterize the distribution of Pb loss in natural samples. Treatment of zircon by chemical abrasion (CA) has become standard practice in isotope dilution–thermal ionization mass spectrometry (ID-TIMS), but CA is much less commonly employed prior to in situ analysis via laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) or secondary ionization mass spectrometry (SIMS). Differentiating the effects of low levels of Pb loss in Phanerozoic zircon with relatively low-precision in situ U–Pb …