Digital Commons Network^™

Macro-Mesoscopic Developmental Patterns Of Cracks In Surrounding Rocks Of Rectangular Roadways Under True Triaxial Stresses, Shi Wenbao, Xu Qingzhao, Chang Jucai, Li Chuanming, Qiao Longquan, Miao Zhuang, Yan Aoyun

Coal Geology & Exploration

Objective and Method This study aims to investigate the relationship between the stress environment and the deformation and failure responses of surrounding rocks, thereby unraveling the inherent mechanisms underlying the deformation and failure. With cement, river sands, and gypsum as raw materials, rectangular roadway model specimens measuring 200 mm × 200 mm × 200 mm were prepared. Using a large-scale true triaxial seepage coupling testing machine, this study conducted triaxial loading tests on the rectangular roadway specimens under different lateral pressure coefficients. Using microcameras and an acoustic emission system, it monitored the whole process of the macroscopic deformation and failure, …

Sensitivity Analysis Of Factors Influencing Water Redistribution In Vadose Zones Under Coal Mining Disturbance In Ecologically Vulnerable Areas, Wang Ao, Liu Shiliang, Wang Shanlin, Zheng Yusheng, Wang Tengye, Wang Zuzhen, Mao Deqiang

Coal Geology & Exploration

Objective Coal mining-induced disturbance leads to water redistribution in the vadose zones of mining areas. The sensitivity analysis of the factors influencing this redistribution holds critical significance for the reconstruction of eco-geological environments and the sustainable economic development in mining areas. Methods Against the engineering background of the Yushen mining area characterized by wind-blown sandy terrain in northern Shaanxi Province, this study analyzed the primary factors influencing water redistribution in the vadose zone under coal mining disturbance. Accordingly, 18 COMSOL Multiphysics numerical models for water redistribution in the vadose zone under coal mining disturbance were constructed through orthogonal experiments. Using …

Current Status And Future Trend Of Research On Underground Borehole Measurement Technology For Coal Mines, Chen Long, Yang Dongdong, Li Quanxin, Chu Zhiwei, Zhang Jiguan, Chen Xiang

Coal Geology & Exploration

Background Underground borehole measurement emerges as a core technology for the safe production of coal mines. Its multi-parameter measurements, data accuracy, data transmission rate, and reliability directly influence the timeliness of early warning for disasters, the operating stability of instruments, the accuracy of borehole assessment, and the scientific rigor of intelligent decision-making under complex deep geological conditions. Advances So far, the measurement while drilling (MWD) and post-drilling borehole visualization techniques have developed into a diversified technological system. Specifically, the MWD technique has achieved a leap from wireline to wireless transmission, obviating the reliance on wireline drill rods in traditional measurement …

Multi-Field Coupling-Based Numerical Simulations Of Co2 Storage In Saline Aquifers: A Case Study Of The Dingji Coal Mine, Huainan Mining Area, Li Dianshang, Zheng Sijian, Liao Qingfa, Miao Wei, Tian Yuchen, Zhang Helong, Liu Yanzhi, Liu Shiqi

Coal Geology & Exploration

Background Saline aquifers are characterized by extensive distribution, abundant reserves, and substantial potential for CO₂ storage, establishing them as the most promising geological media for carbon capture, utilization, and storage (CCUS). CO₂ storage in saline aquifers plays a crucial role in mitigating the greenhouse effect and achieving the goals of peak carbon dioxide emissions and carbon neutrality. Thoroughly investigating CO₂ storage in deep saline aquifers within the Huainan mining area helps alleviate the regional pressure of carbon emission reduction while also providing important support for expanding the technical pathways of CCUS and promoting its engineering applications. Methods …

Key Technical Difficulties, Challenges, And Prospects Of Geologic Co2 Sequestration In Saline Aquifers, Wei Hengfei, Shi Junjie, Nie Xiaodong, Fang Jie, Chen Jing, Zhao Yue, Sun Dawei, Li Xin, Zhang Yong, Guo Pei

Coal Geology & Exploration

Background and Method Carbon capture and storage (CCS) technology represents the primary technical direction for large-scale carbon emission reduction. Among various CCS techniques, geologic CO₂ sequestration in saline aquifers holds great potential, establishing it as a major technique for future carbon storage. Based on a review of the current status of research on global geologic CO₂ sequestration in saline aquifers, this study comprehensively analyzed the technical difficulties, challenges, and prospects of this technology, focusing on the dilemma of the application of this technology under complex geological conditions in China. Results and Conclusions A huge gap in both the …

Environmental Risk Assessment Of Co2 Storage Combined With The Overlying Coal Mining, Gu Leiyu, Li Wenhui, Huang Wei, Zhou Quanchao, Zhu Yalong, Li Xiaying, Liu Guizhen, Li Qi

Coal Geology & Exploration

Objective Carbon capture, utilization, and storage (CCUS) technology serves as a key method for carbon neutrality. However, large-scale engineering applications of CCUS are still confronted with serious challenges of environmental risks. Therefore, systematic environmental risk assessment plays an essential role in ensuring the environmental safety and social acceptability of CO₂ geological storage projects. Methods Targeting the CO₂ geological storage project combined with overlying coal mining in Zhengning County, Gansu Province, this study performed the environmental risk assessment of CO₂ leakage based on the requirements of the Technical Guideline on Environmental Risk Assessment for Carbon Dioxide Capture, Utilization, …

Advances In Research On The Policies, Technologies, And Demonstration Projects Of Geologic Co2 Sequestration In China, Zhao Yue, Yang Xuechao, Chen Xiaodong, Chang Jia, Wei Hengfei, Liu Zhibang, Liu Hui

Coal Geology & Exploration

Background Carbon capture, utilization, and storage (CCUS) is considered a key technology to promote large-scale carbon dioxide (CO₂) emission reduction. Against the backdrop of achieving its goals of carbon neutrality and peak carbon dioxide emissions, China faces a tremendous challenge of CO₂ emission reduction. This situation will provide new driving forces for the development of geologic CO₂ sequestration while also imposing higher requirements for technical innovation and industrialization of the technology. Methods and Advances This study systematically reviews the development process of policies on CCUS of China over the past two decades, with over 30 policies …

Mechanisms Governing Co2 Mineral Trapping And Cementitious Activity Degradation Of Solid Waste-Based Backfill Materials, Liu Zhifei, Chen Qingting, Li Hongjie, Wang En, Zhao Heming

Coal Geology & Exploration

Objective This study investigated three types typical alkaline industrial solid waste: steel slag, fly ash, and bottom ash, highlighting the differences in their CO₂ mineral trapping efficiency and the degradation patterns of their cementitious activity after carbon fixation. The purpose is to reveal the mechanisms underlying CO₂ mineral trapping in solid waste and evaluate their application potential in backfill engineering, thereby promoting the synergistic development of industrial solid waste recycling and carbon emission reduction. Methods Through experiments on CO₂ mineral trapping using the direct wet method, the kinetics and product characteristics of solid waste-CO₂ interactions were …

Variation Characteristics Of Co2 Adsorption Phase Density In Coal Seam And Its Controlling Mechanism: A Case Study Of Huainan-Huaibei Coalfield, Liu Huihu, Fan Zhengpu, Yang Jinghao, Liu Junlin, Ding Hai, Xu Hongjie, Gao Deyi, Fang Huihuang, Zhao Yuqing

Coal Geology & Exploration

Objectives and Methods The CO₂ adsorption phase density is a key factor determining the CO₂ adsorption sequestration capacity in coal seams. To deeply understand the characteristics of CO₂ density distribution in pores of the coal seam, taking the No.13 coal from Liuzhuang Mine of Huainan mining area and the No.7 coal in Huaibei mining area as the research objects, the CO₂ adsorption phase density of at different pressures and temperatures with different dominant pore diameters was simulated through the simplified local density theory (SLD). The CO₂ adsorption phase densities were obtained by different methods, the …

Mechanisms Underlying Sodium Enrichment In Coals In The Dananhu Mining Area, Turpan-Hami Basin, Qi Zhenghui, Sun Fanxing, Wang Wenlong, Huang Chunhui, Liang Kaihua, Huang Yangyang, Shao Longyi

Coal Geology & Exploration

Background The Dananhu mining area boasts abundant coal resources, serving as a significant coal-fired power generation base in Xinjiang, China. However, the high sodium (Na) content in coals within the mining area tends to cause fouling and slagging during coal combustion, severely affecting the clean and efficient utilization of coal resources in the area. Methods and Results epresentative samples collected from the major mineable coal seams were subjected to proximate and ash-composition analyses. The analytical results show that the coal samples had low ash and sulfur contents and high volatile content. SiO₂ predominated in the ash components, followed by …

Water Quality Characteristics And Reutilization Of Goaf Water From Shallow Coal Seams Within The Datong Mining Area, Shanxi Province, China, Li Jun, Gui Herong, Ding Pengfei, Chen Yongqing, Wan Heyong, Li Weiqi, Huang Dawei, Peng Weihua, Hu Yang, Guo Yan

Coal Geology & Exploration

Objective The Datong mining area in Shanxi Province of China faces serious threats from goaf water hazards, while the goaf water drainage is constrained by environmental protection policies. Therefore, the reutilization of goaf water serves as an effective approach to eliminating mine water hazards, protecting water environments, and mitigating water scarcity in the mining area. Methods This study investigated goaf water from shallow coal seams in the Datong mining area. Based on water quality assessment theories and a range of hydrogeochemical indices, including saturation index (SI), chloro-alkaline index (CAI), and sodium adsorption ratio (SAR), this study conducted a joint determination …

Application Of Seismic-While-Tunnelling Detection In The Identification Of Densely Distributed Sub-Seismic Faults, Li Haodang, Li Kang, Chen Jian, Song Xiaozhong, Jin Dan, Wang Baoli

Coal Geology & Exploration

Objective and Method Densely distributed sub-seismic faults have emerged as a major hidden disaster-causing geological factor, heavily influencing both the production efficiency and operational safety of coal mines. To achieve precise advance detection of underground sub-seismic faults in coal mines, this study designed a geological model. Using seismic-while-tunneling (SWT) advance detection technology for roadways of coal mines, this study investigated the geological situation of sub-seismic faults through forward modeling. Furthermore, it explored the seismic image characteristics of these faults obtained using the SWT observation system under varying survey line lengths and geophone spacing values. Results and Conclusions The forward modeling …

Aquifer Distribution In Lukobe Ward, Morogoro Municipality, Tanzania: Mapped Resources For Sustainable Water Access, Kelvin K. Kayuni

Tanzania Journal of Science

In response to the ongoing challenges posed by the scarcity of reliable fresh-water sources in Lukobe Ward, Morogoro Municipality, Tanzania, this study applied an integrated approach that combines geospatial and geophysical datasets to identify previously undocumented aquifers. The datasets utilized include an apparent density map generated from high-resolution GGMPlus satellite gravity data, a geological map (Quarter Degree Sheet 183), a water drainage map, and a slope map created from a digital elevation model (DEM). The analysis successfully identified four unconfined, saprolitic aquifers in the study area, designated as aquifers A, B, C, and D. These aquifers span areas of 12.2 …

Fast Dispersion-Curve Inversion Using Automatic Differentiation Gradient-Based Calculation, Theodosius Marwan Irnaka, Eddy Hartantyo

Makara Journal of Science

Surface wave inversion is a crucial technique in geophysics for subsurface imaging. However, traditional methods can be computationally intensive, especially for complex models. This study introduces automatic differentiation (AD) as an efficient alternative to finite difference (FD) methods for gradient calculation in surface wave inversion. We compare AD and FD methods using three synthetic examples of varying complexity. Our results demonstrate that AD is significantly faster, with speed improvements of 3 to 12 times over FD, depending on model complexity. Moreover, AD requires up to 3 times less memory than FD. In terms of accuracy, AD provides gradient calculations that …

A Cave In Miocene Conglomerate: The Törökpince-Abaliget Cave System, Hungary, Krisztina Sebe, Piroska Pazonyi, Márton Bauer, Bálint Szappanos, Márton Szabó, Zoltán Szentesi, Mihály Gasparik, Ákos Juhász, Luca Pandolfi, Máté Gregorits, József Haász, Ágnes Novothny, Zsófia Ruszkiczay-Rüdiger

International Journal of Speleology

Conglomerate caves are rare, and only a few have been described in the scientific literature. Here, we present a newly discovered and significant cave system in SW Hungary, comprising over 500 m of upper passages and a shorter, lower section of a through-cave developed in Lower–Middle Miocene conglomerates. The formation of these cave passages was controlled chiefly by bedding and fractures. Dissolution has produced typical karstification morphologies, whereas corrasion, granular disintegration, and rock collapse have also played a role in shaping the cave. The cave is dominated by vadose-zone morphologies, but sediment infills indicating upward water flow, along with ceiling …

Macroinvertebrate Community Dynamics In A Recovering, Hypersaline Estuary, Catherine M. Eckert, Claudia A. Tamez, Erin E. Easton, David Hicks

School of Earth, Environmental, & Marine Sciences Faculty Publications

The Bahia Grande is a 6,500—acre tidal basin located at the southernmost tip of Texas. Tidal flow into this coastal estuary was cut off in the 1930s, causing the basin to dry up for ~70 y. A pilot channel connecting the Bahia Grande to tidal waters was constructed in 2005, allowing flooding of the basin to occur. Throughout the period reported herein (2005–2019), the system remained characterized by persistent spatial and temporal episodes of extreme hypersalinity (>70)—a critical factor influencing estuarine community composition and driving key ecological processes. With additional rehabilitation actions forthcoming, characterization of the estuary is essential …

What Does Graptolite Origination And Extinction Reveal About The Cause Of The Late Ordovician Mass Extinction?, Charles E. Mitchell, H. David Sheets, Michael J. Melchin, Chris Holmden

Computer and Data Science Faculty Publications

Assesses the macroevolutionary turnover of paleotropical planktic graptolites during the Late Ordovician Mass Extinction (LOME) via automated sequencing and capture-mark-recapture modeling. Graptolites exhibited a succession of turnover pulses (sensu Elizabeth Vrba) that were coincident with the main phases of the Hirnantian glaciation and during which the Diplograptina experienced declining metapopulation size, elevated extinction, zero species originations, and ultimately, complete extermination. Concurrently, the Neograptina (latest Katian temperate zone immigrants) exhibit pulses of both extinction and adaptive radiation. Thus, the LOME involved intense species selection and the wholesale alteration of the clade diversity structure of a major element of the zooplankton. The …

Linking Shoreline Change, Environmental Forcings, And Sedimentological Resilience In Nourished Beaches Of Cape May And Wildwood, New Jersey, Usa: A Multi-Decadal Synthesis, Divomi Balasuriya, Greg Pope

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

Beach nourishment is a widely used strategy to mitigate coastal erosion, yet its long-term geological impacts remain poorly understood. This study provides a multi-decadal synthesis of shoreline change and sedimentological evolution on the nourished beaches of Cape May and Wildwood, New Jersey, USA. Using shoreline positions from 1991 to 2024, we identify contrasting trajectories: Wildwood exhibits ‘persistent transition’ with severe northern erosion (EPR: −10.0 m/yr) feeding southwards accretion, while Cape May demonstrates a ‘managed equilibrium’ with widespread accretion (mean EPR: +1.15 m/yr). Wave energy correlations account for less than 15% of shoreline variability, indicating natural drivers have been superseded by …

Stability Analysis Of Thermohaline Convection With A Time-Varying Shear Flow Using The Lyapunov Method, Kalin Kochnev

Honors Scholar Theses

This work applies the Lyapunov method to identify instabilities and compute the growth rate of a linear time-varying system. The linear system studied describes cold fresh water on top of hot salty water with a periodically time-varying background shear flow. A time-dependent weighting matrix is employed to construct a Lyapunov function candidate. The resulting linear matrix inequalities are discretized in time using the forward Euler method. As the number of temporal discretization points increases, the growth rate predicted by the Lyapunov method or Floquet theory, used for comparison, will converge to the same value obtained from numerical simulations. Furthermore, the …

Quantifying Biocrust Evaporation In Arid Lands By Combining Thermal Imaging And Lysimeter Measurements, Rebekah C. Magness

UNLV Theses, Dissertations, Professional Papers, and Capstones

Biological soil crusts (biocrusts) are miniature ecosystems of living organisms incorporated within the soil matrix and established in the topmost millimeters of the soil surface. Biocrust plays a critical role in the hydrologic processes in arid lands, yet the extent to which it increases or decreases evaporation remains unclear. To gain a better understanding of the impact of biocrust on evaporation compared to bare soil, I studied a cyanobacteria-dominated biocrust patch surrounded by bare soil atop a lysimeter in the Mojave Desert near Las Vegas, Nevada. Using high-resolution thermal imaging, and the known latent heat flux from the lysimeter, I …

First-Principles Insights Into Binary Oxide Systems Under Extreme Pressure, Daniel Schacher

UNLV Theses, Dissertations, Professional Papers, and Capstones

Pressure is powerful tool by which one can manipulate the properties of materials. In this work we utilize pressure to explore binary oxide systems and characterize their structural and electronic properties. The observation of anomalous structural and electronic behavior in the rutile to CaCl2 phase transition in SnO2 led to the prediction that such behavior is inherent to all oxides experiencing such a phase transition sequence.[1] Here, the ultra-wide band gap semiconductor GeO2 is confirmed to exhibit anomalous behavior during the rutile to CaCl2 phase transition. A phase pure rutile GeO2 sample synthesized under high-pressure, high-temperature, conditions is probed using …

Towards Spatial Inversion Of Aerial Gamma-Ray Survey Data For Measurement Of Naturally Occurring Radioactivity, Daniel A. Haber

UNLV Theses, Dissertations, Professional Papers, and Capstones

Aerial gamma-ray surveying (AGRS) is used in geologic and environmental contexts to provide data on the surface spatial distribution of naturally occurring radioactive material (NORM) or other gamma-ray-emitting isotopes. The standard data reduction workflow for AGRS data involves a process whereby pointwise gamma-ray spectral data are denoised, corrected for numerous sources of background radiation and aircraft height, and are finally converted to physical values by empirical conversion factors. The reduced pointwise data are then typically spatially interpolated to form a continuous surface map.

This dissertation introduces and explores a novel spatial inversion method for reduced AGRS data that considers aircraft …

Reconstructing Central American Hydroclimate Changes Across Time From Isotopic Signatures In Modern And Paleo-Rainfall Records, Giuseppe Lucia

UNLV Theses, Dissertations, Professional Papers, and Capstones

Tropical monsoon rainfall is a key component of Earth’s climate system and supports the livelihood and economy of billions of people. Yet, projections of future monsoons remain highly uncertain, particularly in regions with distinct physiography and complex land-ocean-atmosphere interactions like Central America, where long and continuous high-resolution paleoclimate data to test climate model simulations are still limited. This series of studies aims to reconstruct monsoon dynamics and underlying forcing controls in Central America on multiple timescales by the analysis and integration of stable isotope data in modern and paleo-rainfall records from Guatemala.

In Chapter 2, I present a daily-resolution, two-year-long …

Fault Structure, Deformation Mechanisms, And Why Fault Zones Matter To Society, Elizabeth S. Petrie, David A. Ferrill, Kelly K. Bradbury, James P. Evans

Geosciences Faculty Publications

Faults are widespread geologic structures that form in sediment and all rock types, occur in all tectonic regimes, and can be a blessing or a curse to society. Faults and fault zones act as conduits for underground movement of water and as plumbing systems for aquifers and springs essential for human habitation in many semi-arid and arid regions worldwide. Faults also provide pathways for natural oil and gas migration and high-permeability zones in hydrocarbon reservoirs, as well as barriers contributing to trapping and reservoir compartmentalization. By enhancing permeability in many geothermal energy systems, faults can be essential for fluid circulation …

The Effect Of Phosphate Fertilizer And Organic Matter On Phosphorus Status, Ph, And Cabbage Yield In Andisols, Mahfud Arifin, Emma Trinurani Sofyan, Anni Yuniarti, Rina Devnita, Sastrika Anindita

Jurnal Kultivasi

Andisols are characterized by high phosphorus (P) retention, which often limits P availability for crops. This study aimed to analyze the independent and interactive effects of P fertilizer and organic matter (i.e. manure and rice straw compost) on P retention, total P, available P, P uptake, soil pH, and cabbage yield. This research was conducted in pot experiments in plastic house, applying P fertilizer (0, 90, 180, 270 kg ha-1) and organic matter (20 kg ha-1 of chicken, sheep, cow manures and rice straw compost) on Andisols planted with cabbage. The experiment used a factorial randomized design. The results showed …

Dense Temporary Array Investigation Of Jemez Uplift Seismicity, Jillian D. Podmore

Earth and Planetary Sciences ETDs

A protracted multi-stage tectonic and magmatic evolution combined with low regional crustal strain rates make it challenging to characterize active structure that may host earthquakes in the Jemez Mountains of New Mexico. Here, we leverage temporary 1-month deployments of nodal seismometers to gain new insights into seismicity of the Jemez Mountains, which only have continuous seismic monitoring on their eastern flank as a result of the Los Alamos Seismic Network. Our catalog is built using 4 steps: phase picking in continuous seismic data, association of picks to detect unique events, event magnitude estimation, and absolute hypocenter estimation. We detect and …

Seismological Investigations Of Magmatic Systems Using Dense Nodal Arrays, Wenkai Song

Earth and Planetary Sciences ETDs

Understanding the internal architecture of magmatic systems is crucial for volcanology, yet conventional geophysical techniques often lack the resolution to image their fine-scale structures. This dissertation leverages unique datasets from dense nodal arrays to investigate the upper crustal magmatic systems beneath Yellowstone Caldera, Valles Caldera, and Mount St. Helens. At Yellowstone, I processed vibroseis data to delineate the top of the modern magma reservoir and evaluate the thermal connection between the magmatic and the overlying hydrothermal systems. At Valles, 3D radial seismic anisotropy imaging reveals strong positive radial anisotropy within the reservoir, indicating an organized structure of horizontally sill-like melt …

Contemporary Martian Geomorphic Processes And The Suitability Characterization Of Terrestrial Analogues, Daniel Paul Mason

Earth and Planetary Sciences ETDs

Both historical and contemporary evidence for geomorphic activity on the surface of Mars is apparent. This evidence is showcased by features including a) well-preserved deltaic remnants in an otherwise cold and arid environment, present along the western flank of Jezero Crater, and b) the seasonal appearance of candidate recurring slope lineae throughout Martian equatorial, lower, and mid-latitudes as seen within both the Eos Chasma region and on the walls of Raga, Lohse, Rauna, and Tivat Craters. In this dissertation, I elucidate the role that geomorphic processes, whether aqueous or dry, have played in shaping both the ancient and contemporary Martian …

Microbial Metabolism Amplified Warming In Three Phanerozoic Hyperthermal Events, Yuyang Wu, Haijun Song, Daoliang Chu, Ying Cui, Jacopo Dal Corso, Genming Luo, Huyue Song, Li Tian, Hanchen Song, Enhao Jia, Jinnan Tong

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

The ocean’s biological carbon pump (BCP) plays a crucial role in climate regulation by facilitating long-term removal of atmospheric CO2. However, BCP changes during past hyperthermals remain poorly understood. Here we use the vertical carbon isotope (δ13C) gradients between surface and mid-waters to trace the BCP changes during the Permian−Triassic, early Toarcian, and Palaeocene−Eocene hyperthermals, detecting a two- to three-fold increase in the vertical δ13C gradients. We found that enhanced organic matter remineralization, driven by increased microbial respiration under warming, are the primary trigger for increased vertical δ13C gradients. Warming-induced enhancements in microbial metabolism caused a two- to six-fold reduction …

Flooding Behavior Near The Us/Canada Border: Complications And Approaches, Maria T. Dodson

Honors College Theses

Flood forecasting remains a major challenge due to the nonlinear nature of hydrological systems and uncertainties in environmental data. This study aimed to address the prevalent challenges that arise from forecasting flooding behavior. To address the inherent complexity of hydrological forecasting, a machine learning framework was developed and trained on major contributing factors. To achieve an optimal balance between computational efficiency and predictive performance, a Gated Recurrent Unit (GRU) was selected as the optimal machine learning model. As the chosen dataset, North American Land Data Assimilation System Phase 2 (NLDAS2), is known to have inaccuracies in the important feature Relative …