Digital Commons Network^™

Mechanisms Behind The Impacts Of Co2 Concentration On Microbial Methanogenesis In Coal Seams, Wang Junyu, Liu Bingjun, Jiang Xiangqing, Chen Ruifeng, Xue Sheng, Zhou Wanlong, Yang Yundu

Coal Geology & Exploration

Background Coal seams exhibit the extensive distribution of a variety of indigenous functional microorganisms. Among these, some archaea enable methane metabolism using CO₂ as a substrate, providing the potential for the biological CO₂ storage and utilization in coal seams. However, conventional studies focus primarily on the degradation characteristics of coal matrix, leading to a lack of a systematic understanding of the mechanisms governing the adjustment of the methanation process in CO₂-bearing environments. Methods This study investigated the bituminous coals with a high volatile content in the Huainan mining area. Using laboratory-scale experiments on methanogenesis through anaerobic …

Dynamic Prediction On Goaf Surface Subsidence For The Last Two Periods Based On The Erf Time Function, Ren Lianwei, Li Shihui, Wang Wenchang, Li Zhenhua, Chen Shaojie, Dun Zhilin

Coal Geology & Exploration

Background The surface subsidence induced by coal seam mining represents a continuous dynamic evolution process. Constructing a full-time perdition model for surface subsidence in goafs holds significant theoretical and practical values for the rational utilization of land resources, the safety guarantee of engineering construction, and the transformation and development of resource-based cities. Methods To accurately predict the surface subsidence in goafs during its decline and residual periods, this study proposed a prediction model based on the error function (Erf). First, the evolution characteristics of Erf were analyzed, verifying that the subsidence, as well as its velocity and acceleration, predicted using …

Performance Optimization Of Superfine Cement Through Composite Modification Using Coal-Based Solid Waste And Modifiers, Kang Zhipeng, Luo Yong, Xiao Diancai, Ren Shuai, Cai Zhiliang, Gao Xiang, Zhang Kunzhe

Coal Geology & Exploration

Objective Superfine cement-based grouting materials generally suffer from limitations including high bleeding rates, unfavourable rheological properties, poor stability, and strength retrogression. These issues can be mitigated by incorporating modifiers, which allows for the reutilization of coal-based solid waste while enhancing the performance of composite, superfine cement-based grouting materials. Methods Superfine cement-based grouting materials with different mixing ratios were prepared by using superfine cement as the basic material, fly ash (FA) and mineral fines (MFs) as primary admixtures, and modified bentonite, methyl cellulose ether (MCE), U-type expansive agent (UEA), and magnesium oxide (MgO) as modifiers. These grouting materials and pure superfine …

Dynamic Response Characteristics And Failure Mechanism Of Coal-Rock Combination Under Different Immersion Conditions, Zhang Xiangyang, Tong Zhipeng, Duan Yungang, Yang Weikun, Chen Jianben, Xu Linfeng

Coal Geology & Exploration

Background In practical engineering, the waterproof coal pillar usually suffers from different degrees of dynamic load from the overlying strata, and its internal water distribution is non-uniform. Although the traditional “water content” index can reflect the overall water content, it is difficult to describe the non-uniform characteristics of the soaking space. Therefore, it is of great significance to clarify the dynamic failure mechanism of coal and rock mass under different immersion conditions for stability zoning control. Methods On this basis, the coal–rock combined bodies under three different forms of immersion, namely: complete immersion, unilateral immersion, and non-immersion were prepared. These …

Mine Data Fusion Technology Based On Multi-Feature Joint Decision Making, Han Shanshan, Zhang Jifeng, Fan Tao, Liu Qiang, Song Xiaojiao, Qi Zhipeng, Zheng Hangzhou

Coal Geology & Exploration

Background In the field of geological exploration of coal mines, methods such as in-seam seismic exploration, the transient electromagnetic method, and audio-frequency electrical penetration offer unique technical advantages. However, each of these methods can only reflect a single physical property of a medium, suffering from limitations including the one-sidedness of information and the multiple solutions of interpretations, thus failing to adapt to the new situations of current coal mine exploration. Multi-source data fusion promotes a technological development by leaps from one-sided detection to comprehensive analysis through mechanisms of information complementation, feature enhancement, and field-source integration. Therefore, this technology can enhance …

Mechanisms Underlying Lateral Force Applied To A Pdc Cutter On A Pdc Drill Bit During Rotary Rock Breaking, Wei Jiusen, Han Xin, Liu Wei, Gao Deli

Coal Geology & Exploration

Objective To improve the rock-breaking efficiency and durability of drill bits in the theoretical research on the optimal design of drill bits, the key is to systematically reveal both the rock-breaking mechanisms of polycrystalline diamond compact (PDC) cutters and the characteristics of forces applied to them. Methods Existing studies on rock breaking using a single PDC cutter generally adopt a linear or approximately linear cutting mode while neglecting the impacts of the radius of gyration. To address this issue, this study conducted experiments on cylindrical granite samples using a laboratory experimental setting for single-cutter rock breaking. With cutting depth and …

Reconstructing Nebraska’S Late Quaternary Paleoenvironment, Landscape Change, And Human–Environment Dynamics Using Diatoms And Optically Stimulated Luminescence Dating, Gosia Mahoney

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

This dissertation examines Holocene environmental change and human–environment interactions in the Nebraska Sand Hills by integrating geomorphic, paleoenvironmental, and geochronological data. It presents three complementary studies that together explore how climatic variability, local landscape processes, and human activity influenced environmental systems.

The first study reconstructs the early Holocene evolution of a dune-dammed valley in the central Sand Hills. Stratigraphic, sedimentological, and diatom evidence indicate that eolian activity resulted in a blocked fluvial system, leading to elevated groundwater levels and the formation of a wetland that later developed into a lake. Notably, this transformation occurred under relatively dry conditions, demonstrating that …

Mechanism Of Improved Miscibility Of Co2–Oil Systems By Multiester-Headgroup Surfactants, Ning Xu, Yanling Wang, Baojun Bai, Yu Zhang, Wenjing Shi, Zhaonian Zhang, Wenhui Ding, Peixu Ma, Zan Gao

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

In the pursuit of carbon neutrality, the CO₂-enhanced oil recovery provides dual benefits by enabling both carbon sequestration and incremental oil production. However, its application is limited by high minimum miscibility pressure. CO₂-philic and oil-affinitive surfactants have emerged as an effective, low-dosage, and cost-efficient strategy to reduce the minimum miscibility pressure. In this study, macroscopic phase behavior experiments combined with molecular dynamics simulations were employed to systematically elucidate the influence of multiester-head surfactants on CO₂–oil miscibility. Using a modified pressure–volume–temperature apparatus equipped with optical power monitoring, we determined that multiester-head surfactants reduced the first-contact …

Signatures Of Vapor Evolution In Turbulent Convection Cells Recorded By K And Rb Isotopes In Chicxulub Impact Spherules, Courtney Jean Rundhaug, Martin Schiller, Martin Bizzarro, Zhengbin Deng, Hermann Dario Bermúdez

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

The Cretaceous–Paleogene boundary (∼66 Ma) records the Chicxulub asteroid impact, a pivotal event in Earth's history that affected much of the Earth's surface. While products of this impact have been widely studied, the thermodynamics of the plume and formation mechanisms of certain impact materials remain unclear. This study investigates conditions within the intermediate fraction of the Chicxulub impact plume (pyrocloud) using K and Rb isotope signatures of Gorgonilla Island impact spherules with published δ25Mg data to trace evaporation and condensation processes during ejecta dispersion. The δ41K and δ87Rb signatures vary from −1.18 ± 0.04‰ to 0.43 ± 0.09‰ and − …

Exploring Alternate Methods Of Flood Output Estimation During Natural Disasters, Finley Gardner

Honors College Theses

In April of 2025, extreme flooding damaged many homes and buildings of people across Kentucky. The Federal Emergency Management Agency (FEMA) produces maps that show the potential for flooding in areas around water bodies, but many of the April flooding damaged areas were well outside of the FEMA classification zones. The main purpose of this thesis research was to create an accurate model of potential flood extent in Kentucky and compare it to FEMA maps. This model did not require extensive computing power and produced a map that accurately depicted flood extent through the use of Digital Elevation Model (DEM) …

Challenges In Strategic Exploitation Of Deep-Sea Minerals And China’S Countermeasures, Chang Wang, Xiaojie Shu, Siyuan Zhou, Huiling Song, Shaojun Liu, Xiangxin Xu, Tao Dai, Tao Zhang, Peng Wang, Zheng Li, Jinhua Cheng

Bulletin of Chinese Academy of Sciences (Chinese Version)

Facing the new stage of strategic mining of deep-sea minerals and the long-term pressure of supply of critical minerals, China urgently needs to seize the window of opportunity for the strategic exploitation of deep-sea critical minerals and open up new sources of supply of critical minerals. Having analyzed the new global situation and challenges of the strategic exploitation of deep-sea critical mineral resources, the study attempted to clarify the supporting role of deep-sea mining in securing critical mineral supply, as well as the actual conditions and main obstacles for the strategic exploitation of deep-sea critical mineral resources in China. Based …

Plastic Purgatory: Investigating The Effects Of Plastic Litter On Water And Organic Content In Topsoil In Holland, Michigan, Kamryn Bice, Annis Cairns, Maddie Devries, Sebastian Lema

25th Annual A. Paul and Carol C. Schaap Celebration of Undergraduate Research and Creative Activity (2026)

Plastic accumulation in soils can offer important insights into how human activity affects terrestrial ecosystems. In this study, we examined the relationship between plastic litter and soil quality at several sites across Holland, Michigan to determine whether plastic abundance was associated with changes in soil properties. Soil samples from five different site types – construction, residential, commercial, nature, and a control – were collected over a threeweek period, then analyzed for pH, water contents, total organic carbon (TOC), and plastic abundance through field testing and laboratory methods. The number of plastic pieces ranged from 0 to 27 with the largest …

Recent Wetland Elevation Dynamics In Coastal Louisiana, Usa, Elizabeth Harris

LSU Master's Theses

Coastal marshes globally are increasingly vulnerable to accelerating relative sea-level rise (RSLR), which threatens their capacity to maintain elevation through feedbacks among sediment supply, vegetation productivity, hydrology, and soil processes. Although many marshes can persist under moderate rates of sea-level rise through vertical accretion and belowground biomass production, this resilience is strongly constrained by sediment availability and subsurface processes such as autocompaction and organic matter decomposition. High accretion is often assumed to confer marsh resilience; however, subsurface processes, particularly autocompaction driven by surface loading, can substantially offset elevation gains. Coastal Louisiana experiences among the highest rates of RSLR worldwide due …

High Germinability Can Facilitate Recovery Of Adelia Vaseyi (Euphorbiaceae), An Imperiled Tamaulipan Thornscrub Shrub, Saroj Dhakal, Bashira Chowdhury, Alejandro Fierro-Cabo

School of Earth, Environmental, & Marine Sciences Faculty Publications

While critical to maintaining dryland biodiversity and drought resilience, reforestation has been limited in subtropical dry forests because of knowledge gaps in seed biology that must be filled to upscale seedling production and ensure recovery of imperiled endemic plants. We characterized seed germination, dormancy, and storage needs for Adelia vaseyi, a threatened endemic shrub commonly included in planting mixes to restore Tamaulipan thornscrub, an imperiled subtropical forest spanning South Texas and Northeastern Mexico. We found A. vaseyi seeds have high germinability (82.0%) and a short mean germination time (3.04 ± 0.08 days). A delia vaseyi seed does not appear …

Engineering Ferrate(Vi) For Water And Wastewater Treatment: Translating Science Into Technology, Zepei Tang, Zhenli He, Yang Deng

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

Over the past five decades, ferrate(VI) (FeO42–) for water and wastewater treatment has remained largely at the laboratory scale, with limited pilot- and full-scale implementation. This gap between sustained research and scarce real-world deployment places the technology in the Valley of Death─a high-risk stage of development─and highlights the need for an engineering-centric approach to enable practical application. This article presents an engineering framework to guide the development and translation of ferrate(VI) technology for water and wastewater treatment. From a system perspective, ferrate(VI) technology comprises three core subsystems: generation, treatment, and solid–liquid separation. Technology maturity depends on both the advancement of …

Integrating Multi-Source Data With Machine Learning Techniques To Upscale Wetland Carbon Dioxide Fluxes, Abdullah Sulaiman Abdullah Al Fazari

Electronic Theses and Dissertations

Accurate quantification of atmospheric carbon dioxide (CO₂) fluxes in wetland ecosystems is essential for understanding their role in both regional and global carbon dynamics, particularly in the context of climate change. However, the spatial and temporal heterogeneity of wetlands presents major challenges for developing reliable upscaling models. This research developed and validated a comprehensive framework to upscale CO₂ fluxes across the Everglades National Park (ENP) and Big Cypress National Preserve (BCNP) in South Florida through the integration of multi-source datasets, including AmeriFlux eddy covariance (EC) tower measurements, NASA’s BlueFlux airborne CO₂ data, and multispectral satellite imagery from Landsat 8 OLI …

Drainage Proximity And Sinkhole Occurrence In Sivrihisar (Central Turkey): A Comparative Analysis Of Linear, Poisson, And Negative Binomial Regression Models, Bilge Bingül, Emrah Pekkan, Resul Çömert

International Journal of Speleology

This study investigates the relationship between sinkhole occurrence and distance to drainage in the Sivrihisar region (Central Turkey) and evaluates the suitability of different regression approaches for modeling clustered count data in karst terrains. A comprehensive inventory of 104 sinkholes developed within the Neogene lacustrine limestones of the Akpınar Formation was compiled using official records, remote sensing analyses, and detailed field surveys. Sinkhole occurrences were analyzed relative to a drainage network derived from a high-resolution Digital Surface Model and grouped by proximity to drainage lines. Linear Regression (LM), Poisson Regression (PR), and Negative Binomial Regression (NBR) models were comparatively applied …

Stylemys Nebrascensis Predation Hypothesis, Noah Lohrmeyer, Amanda Peng

SACAD: Scholarly Activities

In 2008 a fossilized tortoise shell was brought into the Sternberg Museum of Natural History. As we prepared the fossil, we observed markings that resembled predation. We are trying to find what species from the White River Formation could preyed on the tortoise. There are few publications on predation for this species. With few publications, we want to find what predator would hunt these species. We cross referenced the site of the tortoise and observed several carnivorous species. We used straight carapace length (Hermanson et al., 2024) and a regression formula (Wilson et al., 2016) to analyze the species we …

Mumm Vs. Minium: A Tale Of Two Quarries, Kale Link, Amanda Peng

SACAD: Scholarly Activities

In 2025, a discrepancy was discovered in the field numbers of a selection of mammal fossils, which had been mistakenly catalogued as originating from the Minium Quarry in Graham County, KS instead of the Mumm Quarry in Rawlins County, KS. While both quarries belong to the Ogallala Formation, they demonstrate differing biostratigraphic ages, faunal assemblages, and taphonomic settings. Mumm is Clarendonian aged, while Minium is Hemphillian. To correct this issue, all the Mumm specimens were assigned to an updated locality with more precise geographic and biostratigraphic data.

Flood Frequency Analysis Of Big Creek, Ryan S. Funai, Jason T. Santoli, Gunnar F. Wainscott, Callen Zurn

SACAD: Scholarly Activities

The primary purpose of flood frequency analysis is to determine a timeframe of potential flood events. Analyzing flood frequency is a process that involves collecting years of quantitative data on discharge rates, calculating the probability of exceeding a certain rate of discharge, and calculating the average interval between events equaling or exceeding a certain rate of discharge. The Big Creek Watershed drainage area covers an area of 549 square miles in Western Kansas, including Ellis, Trego, Gove, and Sheridan Counties. This research analyzes 79 years of data collected by the USGS at the intersection of Big Creek and US-183. Water …

Fhsu Western Kansas Regional Water Quality Study, Gunnar F. Wainscott

SACAD: Scholarly Activities

This study, conducted by Fort Hays State University faculty and graduate students, aims to analyze water quality through systematic sampling and analysis of wells, ponds, and streams across the region. Each sample is analyzed for a suite of eighteen parameters, such as arsenic, lead, nitrate, etc. By combining laboratory results with spatial data, this project seeks to identify regional patterns, establish a foundation for future monitoring efforts, and provide participating landowners with clear, accessible information about their own water quality.

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