Chemical Engineering Commons^™

Seismicity Characteristics Of The Gulf Of Aqaba Seismogenic Zone And Their Hazard Implications In Northwestern Saudi Arabia, Ali Abdelfattah, Mohamed Ezzelarab, Hazem Badreldin, Hassan Alzahrani, Saleh Qaysi, Bassam Abuamarah, Neil Lennart Anderson

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

The seismogenic characteristics of the Gulf of Aqaba zone have been assessed using the maximum likelihood method to estimate various earthquake recurrence parameters. These parameters encompass the β-value, annual recurrence rate (λ), and maximum probable magnitude (Mmax). This assessment has identified three sub-seismogenic zones, each corresponding to specific structural faults within the Gulf. These zones are associated with the Aragonese, Arnona and Aqaba faults, delineating pull-apart basin structures in the Gulf of Aqaba. An updated earthquake catalogue has been compiled using a unified moment magnitude (Mw) scale to improve the analysis, established by developing two empirical relationships. According to the …

Cfd Study On Two-Phase Flow Patterns In A Pipe With 90º Elbow In Different Operating Conditions, Hagar Alm-Eldin Bastawissi, Mohammed Ahmed Khafagy, E. A. El Shenawy Prof. Dr., Ahmed M. Salem Dr

Journal of Engineering Research

Recently, CFD has offered a technological solution for modelling multi-phase flow in which we can make endless simulations with reduced expenses and effort in high accuracy results; we shall also mention that experimental studies have limitations for safety considerations when experimenting with flow in high temperature or pressure values or medium nature as in nuclear or chemical flows.In this paper, we used the ANSYS FLUENT CFD program to simulate the two-phase flow in a pipe to study the effect of attaching a 90-degree elbow fitting to the piping system, seeking to find out the change in the pattern and resulting …

Investigation Of Gas Dynamics In Water And Oil-Based Muds Using Das, Dts, And Dss Measurements, Temitayo S. Adeyemi

LSU Master's Theses

Reliable prediction of gas migration velocity, void fraction, and length of gas-affected region in water and oil-based muds is essential for effective planning, control, and optimization of drilling operations. However, there is a gap in our understanding of gas behavior and dynamics in water and oil-based muds. This is a consequence of the use of experimental systems that are not representative of field-scale conditions. This study seeks to bridge the gap via the well-scale deployment of distributed fiber-optic sensors for real-time monitoring of gas behavior and dynamics in water and oil-based mud. The aforementioned parameters were estimated in real-time using …

Understanding Effective Elastic Properties And Stress-Strain Evolution In Composite Granular Rocks Using Discrete Element Modeling, Prasad Pothana, Fernando E. Garcia, Kegang Ling

Petroleum Engineering Posters and Presentations

The mechanical behavior of composite granular rocks is a multifaceted phenomenon relevant to various geoengineering applications. Traditional homogenization models and continuum mechanics-based numerical methods often fall short of accurately capturing the intricacies of granular materials. Granular materials exhibit heterogeneity and arching mechanisms governing the force networks that ensure system stability. Unlike continuum-based approaches, particulate discrete element methods have an advantage in assessing effective material properties by considering material heterogeneity and grain-level physical interactions. This study evaluates effective elastic properties using particle flow code using flat-joint contact law for composite binary mixtures with a stiff inclusion embedded within a matrix material. …

Layered Mantle Flow Field Associated With Plate Kinematics And Slab Modulation Underneath The Horseshoe-Shaped Banda Arc-Islands, Sijia Li, Fansheng Kong, Kelly H. Liu, Stephen S. Gao

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

The Banda Arc-Continent Collision Zone Signifies One Of The Most Seismically Active And Tectonically Intricate Zones. The High Convergence Rate Across The Region, Coupled With The Exceptionally Arcuate Arc And Subducted Slab, Makes It An Ideal Locale For Investigating Interactions Between Plate (Slab) Kinematics And Plastic Flow In The Asthenosphere, Which Can Be Diagnosed By Seismic Anisotropy From Shear Wave Splitting Analyses. In Total, 206 Pairs Of Splitting Measurements Using Teleseismic SKS, SKKS, And PKS, Along With 43 Pairs Using Local S Phases, Are Obtained By Utilizing Broadband Seismic Data From Five Permanent Seismic Stations. To Reduce The Ambiguity In …

Laboratory Evaluation Of High-Temperature Resistant Lysine-Based Polymer Gel Systems For Leakage Control, Tao Song, Xuyang Tian, Baojun Bai, Yugandhara Eriyagama, Mohamed Ahdaya, Adel Alotibi, Thomas P. Schuman

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

In-situ crosslinking gel known for its cost-effectiveness, has been employed for decades to plug high-permeability features in subsurface environments. However, some commonly used crosslinkers are being phased out due to the increasingly rigorous environmental regulations. As a newly discovered environmentally friendly crosslinker, lysine can crosslink the partially hydrolyzed polyacrylamide through transamidation reaction. The present work aimed to study the effect of polymer composition and concentration on the gelation behavior of lysine and high molecular weight acrylamide-based polymers. Several commercial high molecular weight polymers with different contents of 2-Acrylamido-2-methyl-1-propane sulfonic acid (AMPS) including AN-105/125, SAV-55/37/28, and SAV-10 were deployed in this …

Inverting Geodetic Strain Rates For Slip Deficit Rate In Complex Deforming Zones: An Application To The New Zealand Plate Boundary, Kaj M. Johnson, Laura M. Wallace, Jeremy Maurer, Ian Hamling, Charles Williams, Chris Rollins, Matt Gerstenberger, Russ Van Dissen

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

The potential for future earthquakes on faults is often inferred from inversions of geodetically derived surface velocities for locking on faults using kinematic models such as block models. This can be challenging in complex deforming zones with many closely spaced faults or where deformation is not readily described with block motions. Furthermore, surface strain rates are more directly related to coupling on faults than surface velocities. We present a methodology for estimating slip deficit rate directly from strain rate and apply it to New Zealand for the purpose of incorporating geodetic data in the 2022 revision of the New Zealand …

Development Of Inorganically Cross-Linked Sulfonated Polyacrylamide Preformed Particle Gels For Conformance Control: Impact Of Anionic Groups, Reem Elaf, Ahmed Hamza, Hassan Nimir, Mohammed Saad, Ibnelwaleed A. Hussein, Baojun Bai

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Modern oil and gas extraction faces challenges, notably from the surplus of produced water, hampering hydrocarbon recovery and raising environmental and economic concerns. A promising solution is the injection of preformed particle gels (PPGs) into the reservoir's fractures and high permeability zones, facilitating production processes. This study introduces a novel class of inorganically cross-linked PPGs with exceptionally high swelling capacities, comprising sulfonated polyacrylamide cross-linked with aluminum attached to acetate, nitrate, sulfate, and lactate anions individually. These PPGs function as superabsorbents, capable of absorbing water at a ratio of 100-700 times their dry weight while maintaining adequate gel strength up to …

Integrated Petrophysical Evaluation And Rock Physics Modeling Of Broom Creek Deep Saline Aquifer For Geological Co2 Storage, Prasad Pothana, Ghoulem Ifrene, Kegang Ling

Petroleum Engineering Student Publications

Fossil fuels, such as coal and hydrocarbons, are major drivers of global warming and are primarily responsible for worldwide greenhouse gas emissions, including carbon dioxide CO₂. The storage of CO₂ in deep saline reservoirs is acknowledged as one of the top practical and promising methods to reduce CO₂ emissions and meet climate goals. The North Dakota Industrial Commission (NDIC) recently approved the fourth Class VI permit for a carbon capture and storage project in the Williston basin of North Dakota for the geological CO₂ storage in the Broom Creek formation. The current research aimed to …

Geodetic Strain Rates For The 2022 Update Of The New Zealand National Seismic Hazard Model, Jeremy Maurer, Kaj Johnson, Laura M. Wallace, Ian Hamling, Charles A. Williams, Chris Rollins, Matt Gerstenberger, Russ Van Dissen

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Geodetic data in plate boundary zones reflect the accrual of tectonic strain and stress, which will ultimately be released in earthquakes, and so they can provide valuable insights into future seismic hazards. To incorporate geodetic measurements of contemporary deformation into the 2022 revision of the New Zealand National Seismic Hazard Model 2022 (NZ NSHM 2022), we derive a range of strain-rate models from published interseismic Global Navigation Satellite Systems velocities for New Zealand. We calculate the uncertainty in strain rate excluding strain from the Taupō rift–Havre trough and Hikurangi subduction zone, which are handled separately, and the corresponding moment rates. …

Upper Plate And Subduction Interface Deformation Models In The 2022 Revision Of The Aotearoa New Zealand National Seismic Hazard Model, Russ J. Van Dissen, Kaj M. Johnson, Hannu Seebeck, Laura M. Wallace, Chris Rollins, Jeremy Maurer, Matthew C. Gerstenberger, Charles A. Williams, Ian J. Hamling, Andrew Howell, Christopher J. Dicaprio

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

As part of the 2022 revision of the Aotearoa New Zealand National Seismic Hazard Model (NZ NSHM 2022), deformation models were constructed for the upper plate faults and subduction interfaces that impact ground-shaking hazard in New Zealand. These models provide the locations, geometries, and slip rates of the earthquake-producing faults in the NZ NSHM 2022. For upper plate faults, two deformation models were developed: a geologic model derived directly from the fault geometries and geologic slip rates in the NZ Community Fault Model version 1.0 (NZ CFM v.1.0); and a geodetic model that uses the same faults and fault geometries …

Characterizing Nonlinear Fluid Flow In 3d Printed Rock Fractures: Effects Of Roughness, Aperture, And Intersection Angles, Ghoulem Ifrene, Prasad Pothana, Sven Egenhoff, Nicholas Bittner, Kuldeep Singh

Petroleum Engineering Posters and Presentations

Understanding fluid flow behavior at fracture intersections is vital to geothermal energy extraction, underground water flow, and CO₂ storage. Here, laboratory experiments were performed to study the effect of surface roughness, intersection angles, and aperture on nonlinear flow behavior in simple fracture networks. A FormLabs (3B+) 3D printer was used to fabricate 8 samples of 38.1mm in diameter and 59.43mm or 54.9mm in length with 2 intersecting fractures of 10^o and 40^o respectively. The surface roughness of the fractures was based on laser profilometry measurements from two induced mode 1 rock fractures, with a joint roughness coefficient …

The Comprehensive Study Of High Viscosity Friction Reducers In High-Tds And High-Temperature Environments, Xiaojing Ge

Doctoral Dissertations

"High viscosity friction reducers (HVFRs) have been recently gaining more attention and increasing in use, not only as friction-reducing agents but also as proppant carriers. Reusing of produced water has also been driven by both environmental and economic benefits. Currently, most friction reducers on the market are anionic friction reducers, which are fully compatible with most produced water with low to medium level of Total Dissolved Solids (TDS) but show a significant drop at high TDS conditions in term of their friction reduction performance in most cases. On the contrary, cationic friction reducers are believed to have better TDS tolerance …

Assessing The Potential Of Uav-Based Multispectral And Thermal Data To Estimate Soil Water Content Using Geophysical Methods, Yunyi Guan, Katherine R. Grote

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Knowledge of the soil water content (SWC) is important for many aspects of agriculture and must be monitored to maximize crop yield, efficiently use limited supplies of irrigation water, and ensure optimal nutrient management with minimal environmental impact. Single-location sensors are often used to monitor SWC, but a limited number of point measurements is insufficient to measure SWC across most fields since SWC is typically very heterogeneous. To overcome this difficulty, several researchers have used data acquired from unmanned aerial vehicles (UAVs) to predict the SWC by using machine learning on a limited number of point measurements acquired across a …

A Review Of Dielectric Barrier Discharge Cold Atmospheric Plasma For Surface Sterilization And Decontamination, Kolawole Adesina, Ta Chun Lin, Yue-Wern Huang, Marek Locmelis, Daoru Frank Han

Biological Sciences Faculty Research & Creative Works

Numerous investigations have shown that non-equilibrium discharges at atmospheric pressure, also known as "cold atmospheric plasma" (CAP) are efficient to remove biological contaminants from surfaces of a variety of materials. Recently, CAP has quickly advanced as a technique for microbial cleaning, wound healing, and cancer therapy due to the chemical and biologically active radicals it produces, known collectively as reactive oxygen and nitrogen species (RONS). This article reviews studies pertaining to one of the atmospheric plasma sources known as Dielectric Barrier Discharge (DBD) which has been widely used to treat materials with microbes for sterilization, disinfection, and decontamination purposes. To …

Evaluation Of Novel Preformed Particle Gel System For Conformance Control In Mature Oil Reservoirs, Abdulaziz Almakimi, Ahmed Ben Ali, Ibnelwaleed A. Hussein, Baojun Bai

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

To address challenges associated with excessive water production in mature oil reservoirs, this study introduces a carboxymethyl cellulose (CMC)-based material as a novel preformed particle gel (PPG) designed to plug excessive water pathways and redistribute the subsequent injected water toward unswept zones. Through microwave-assisted grafting copolymerization of CMC with acrylamide (AM), we successfully generated multi-sized dry particles within the range of 250–800 µm. Comprehensive analyses, including Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM), have confirmed the chemical composition and morphology of the resulting carboxymethyl cellulose-grafted crosslinked polyacrylamide (CMC/PAMBA). Swelling kinetics and rheology tests were conducted to confirm the …

Investigation Of Asphaltene Instability Under Gas Injection In Unconventional Reservoirs And Its Impact On Oil Recovery Performance, Mukhtar Elturki

Doctoral Dissertations

"Unconventional reservoirs, such as shale gas and tight oil formations, have become an important source of energy in recent years. However, these reservoirs often contain high levels of asphaltenes, which can lead to deposition and blockages in production wells and reduce the flow of hydrocarbons during gas enhanced oil recovery (GEOR) techniques. This study aims to experimentally evaluate the impact of miscible and immiscible carbon dioxide (CO₂) and nitrogen (N₂) on asphaltene deposition and its impact on oil recovery performance in unconventional shale reservoirs.

This research began with a comprehensive literature review and data analysis of GEOR methods in unconventional …

Oxygen Fugacity Of Global Ocean Island Basalts, Lori N. Willhite, Ricardo Arevalo, Philip Piccoli, John C. Lassiter, Devin Rand, Matthew G. Jackson, James M.D. Day, Robert W. Nicklas, Marek Locmelis, Thomas J. Ireland, Igor S. Puchtel

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Mantle plumes contain heterogenous chemical components and sample variable depths of the mantle, enabling glimpses into the compositional structure of Earth's interior. In this study, we evaluated ocean island basalts (OIB) from nine plume locations to provide a global and systematic assessment of the relationship between fO₂ and He-Sr-Nd-Pb-W-Os isotopic compositions. Ocean island basalts from the Pacific (Austral Islands, Hawaii, Mangaia, Samoa, Pitcairn), Atlantic (Azores, Canary Islands, St. Helena), and Indian Oceans (La Réunion) reveal that fO₂ in OIB is heterogeneous both within and among hotspots. Taken together with previous studies, global OIB have elevated and heterogenous fO …

Geochemical Assessment Of Mineral Sequestration Of Carbon Dioxide In The Midcontinent Rift, Alsedik Abousif, David J. Wronkiewicz, Abdelmoniem Masoud

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

This Study Examines The Potential Of Midcontinent Rift Rocks To Facilitate Long-Term CO2 Sequestration By Providing The Necessary Ca And Mg For Carbonate Mineralization. Surface Samples Were Collected From The Oronto And Bayfield-Jacobsville Groups Around Lake Superior And Used For Petrography And X-Ray Diffraction To Determine Their Mineral Composition. Also, X-Ray Fluorescence Was Also Used To Assess Their Bulk Chemical Composition. The Samples Were Then Exposed To CO2 And Deionized Water In Teflon-Lined Vessels At 90°C, And The Resulting Leachate Fluids Were Analyzed For The Cation Released During The Testing. SEM Microscopy Was Used To Examine The Samples For Potential …

Mantle Flow And Olivine Fabric Transition In The Myanmar Continental Subduction Zone, Enbo Fan, Yinshuang Ai, Stephen S. Gao, Yumei He, Kelly H. Liu, Mingming Jiang, Guangbing Hou, Shun Yang, Chit Thet Mon, Myo Thant, Kyaing Sein

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

One of the Major Advances in Mineral Physics and Seismology is the Realization that Different Olivine Fabric Types Are Functions of Temperature, Shear Stress, and Water Content in Oceanic Subducting Systems. the Distribution of Different Olivine Fabric Types and Geodynamic Processes in the Mantle Wedge above a Subducting Continental Slab Remain Poorly Understood. Here, based on Splitting Analysis of Shear Waves Recorded by 46 Stations Recently Deployed in Central Myanmar, We Reveal Trench-Perpendicular Fast Orientations between the 80 and 100 Km Slab Contours Sandwiched between Trench-Parallel Fast Orientations from the Mantle Wedge Tip to the Backarc. the Dramatic Change in …

Preclassic Environmental Degradation Of Lake Petén Itzá, Guatemala, By The Early Maya Of Nixtun-Ch’Ich’, Brooke A. Birkett, Jonathan Obrist-Farner, Prudence M. Rice, Wesley G. Parker, Peter M.J. Douglas, Melissa A. Berke, Audrey K. Taylor, Jason H. Curtis, Benjamin Keenan

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Paleolimnological Evidence Indicates the Ancient Maya Transformed Terrestrial Ecosystems by Felling Forest Vegetation to Construct Large Civic-Ceremonial Centers and to Expand Agriculture. Human Settlements Influenced Lacustrine Environments But the Effects of Maya Activities on Aquatic Ecosystems Remain Poorly Studied. Here We Analyzed a Sediment Core from Lake Petén Itzá, Guatemala, to Infer Paleoenvironmental Changes Resulting from Maya Occupation of the Archaeological Site of Nixtun-Ch'ich'. Increases in Charcoal and Fecal Stanol Concentrations Indicate Maya Occupation of the Candelaria Peninsula by the Late Early Preclassic Period. Geochemical Proxies Reveal a Period of Lake Ecosystem Alteration during Construction and Expansion of the City's …

Development Of Eco-Friendly Chitosan-G-Polyacrylamide Preformed Particle Gel For Conformance Control In High-Temperature And High-Salinity Reservoirs, Reem Elaf, Ahmed Ben Ali, Mohammed Saad, Ibnelwaleed A. Hussein, Baojun Bai

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Oil and gas extraction has become challenging nowadays due to the accompanying amount of excess produced water that results in poor recoverability of hydrocarbon, besides other environmental and economic isues. A recent and efficient technology for conformance control is the injection of preformed particle gels (PPGs), which results in a more practical production process. Nevertheless, existing treatments fail in high-temperature reservoirs, are extremely sensitive to salinity, and are hazardous. The characteristics of the designed PPG, such as mechanical strength and thermal durability, is mainly depend on their crosslinking method. Polysaccharides-based gels prepared by physical crosslinking are weaker than the ones …

Landscape Position And Cover Crops Affects Crop Yields In A Terrace-Tiled Field, Harpreet Kaur, Kelly A. Nelson, Gurbir Singh, Gurpreet Kaur, Katherine R. Grote

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Cover Crops (CC) Provide Soil Ecosystem Benefits Including Reduced Soil Erosion, Improved Soil Health, and Nutrient Cycling. However, the Effect of CCs on Rotational Commodity Crop Grain Yields and Nutrient Uptake May Vary at Different Landscape Positions and under Different Soil Moisture Dynamics. the Objectives of This Study Were to Determine the Influence of CCs in a Terraced Field on Soil Moisture at Crop Emergence and Reproductive Stages of Corn (Zea Mays L) and Soybean (Glycine Max L. Merr.) Development, and Evaluate CCmix (Wheat (Triticum Aestivum L.), Radish (Raphanus Raphanistrum Subsp. Sativus), and Turnip (Brassica Rapa Subsp. Rapa)) and Cereal …

Planning For The Lake Izabal Basin Research Endeavor (Libre) Continental Scientific Drilling Project In Eastern Guatemala, Jonathan Obrist-Farner, Andreas Eckert, Peter M.J. Douglas, Liseth Perez, Alex Correa-Metrio, Bronwen L. Konecky, Thorsten Bauersachs, Susan Zimmerman, Stephanie Scheidt, Mark Brenner, Steffen Kutterolf, Jeremy Maurer, Omar Flores, Caroline M. Burberry

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

As Earth's atmospheric temperatures and human populations increase, more people are becoming vulnerable to natural and human-induced disasters. This is particularly true in Central America, where the growing human population is experiencing climate extremes (droughts and floods), and the region is susceptible to geological hazards, such as earthquakes and volcanic eruptions, and environmental deterioration in many forms (soil erosion, lake eutrophication, heavy metal contamination, etc.). Instrumental and historical data from the region are insufficient to understand and document past hazards, a necessary first step for mitigating future risks. Long, continuous, well-resolved geological records can, however, provide a window into past …

Mantle Flow Underneath The South China Sea Revealed By Seismic Anisotropy, Fansheng Kong, Rui Gao, Stephen S. Gao, Kelly H. Liu, Weiwei Ding, Xiongwei Niu, Aiguo Ruan, Pingchuan Tan, Jianke Fan, Shaoping Lu, Zhengyi Tong, Liqun Cheng, Wenfei Gong, Yanghui Zhao

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

It Has Long Been Established that Plastic Flow in the Asthenosphere Interacts Constantly with the overlying Lithosphere and Plays a Pivotal Role in Controlling the Occurrence of Geohazards Such as Earthquakes and Volcanic Eruptions. Unfortunately, Accurately Characterizing the Direction and Lateral Extents of the Mantle Flow Field is Notoriously Difficult, Especially in Oceanic Areas Where Deployment of Ocean Bottom Seismometers (OBSs) is Expensive and Thus Rare. in This Study, by Applying Shear Wave Splitting Analyses to a Dataset Recorded by an OBS Array that We Deployed between Mid-2019 and Mid-2020 in the South China Sea (SCS), We Show that the …

Stress-Dependent Petrophysical Properties Of The Bakken Unconventional Petroleum System: Insights From Elastic Wave Velocities And Permeability Measurements, Prasad Pothana, Ghoulem Ifrene, Kegang Ling

Petroleum Engineering Student Publications

The net-effective stress is a fundamental physical property that undergoes dynamic changes in response to variations in pore pressure during production and injection activities. Petrophysical properties, including porosity, permeability, and wave velocities, play a critical role and exhibit strong dependence on the mechanical stress state of the formation. The Williston basin’s Bakken Formation represents a significant reservoir of hydrocarbons within the United States. To investigate this formation, we extracted core plugs from three distinct Bakken members, namely Upper Bakken, Middle Bakken, and Lower Bakken. Subsequently, we conducted a series of measurements of ultrasonic compressional and shear wave velocities, as well …

Experimental Data Supporting Co2 Enhanced Oil Recovery And Storage Potential In The Bakken Petroleum System (Bps), University Of North Dakota. Energy And Environmental Research Center

EERC Brochures and Fact Sheets

Fact sheet on CO₂ enhanced oil recovery (EOR) in the Bakken petroleum system. Highlights experimental data concerning CO₂’s role in oil recovery in the region.

Quantification Of Geodetic Strain Rate Uncertainties And Implications For Seismic Hazard Estimates, Jeremy Maurer, Kathryn Materna

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Geodetic velocity data provide first-order constraints on crustal surface strain rates, which in turn are linked to seismic hazard. Estimating the 2-D surface strain tensor everywhere requires knowledge of the surface velocity field everywhere, while geodetic data such as Global Navigation Satellite System (GNSS) only have spatially scattered measurements on the surface of the Earth. To use these data to estimate strain rates, some type of interpolation is required. In this study, we review methodologies for strain rate estimation and compare a suite of methods, including a new implementation based on the geostatistical method of kriging, to compare variation between …

Use Of Photo Isomers To Enhance The Removal Of Lignin From Woody Biomass Hydrolysate, Dipesh J. Karki

Electronic Theses and Dissertations

In this investigation we propose a novel method to enable precipitation of desired solutes using photo-isomers in the extraction solvent. This photo-switchable solvent would enable dissolution or precipitation of desired components using alternating UV or visible light to modify the solubility of the compounds of interest. Three photo-isomers namely native azobenzene, diethoxy azobenzene and diethylamino azobenzene were studied in three different organic solvents: medium chain length alcohol, ethanol and acetone. It was found that among the different combinations of solvent and photo-isomer, acetone and the 4,4’-diethoxy azobenzene solution was most efficient at precipitating dissolved lignin in response to UV light …

Distinct Modes Of Aged Soil Carbon Export In A Large Tropical Lake Basin Identified Using Bulk And Compound-Specific Radiocarbon Analyses Of Fluvial And Lacustrine Sediment, Wesley G. Parker, Jason M.E. Ahad, Jonathan Obrist-Farner, Benjamin Keenan, Peter M.J. Douglas

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

The 14C content of sedimentary organic matter (OM) and specific organic molecules provide valuable information on the source and age of OM stored in sediments, but these data are limited for tropical fluvial and lake sediments. We analyzed 14C in bulk OM, palmitic acid (C16), and long-chain n-alkanoic acids (C24, C26, and C28), within fluvial and lake sediments in the catchment of Lake Izabal, a large tectonic lake basin in Guatemala. We combined these measurements with bulk and compound-specific δ13C measurements, as well as sediment organic carbon to nitrogen (OC:N) ratios, to understand the source and age of sedimentary OM …