Oil, Gas, and Energy Commons^™

High Frequency Dc-Dc Converter Design Optimization, Modeling And Control Based-Wbg Technology., Salah Ahmed Abdullah Eltief

Electronic Theses and Dissertations

The performance of DC-DC power converters is a cornerstone of modern electric vehicle (EV) powertrains, directly governing overall system efficiency, size, cost, and reliability. This dissertation presents a comprehensive performance analysis and optimization of DC-DC converter topologies to determine the most suitable design for high voltage EV applications. The evaluation rigorously compares efficiency, power losses, and physical size under a range of harsh operating conditions. A primary objective is to leverage Wide Bandgap (WBG) semiconductors, specifically Silicon Carbide (SiC), to push the performance boundaries of power conversion. While SiC devices are known for their superior material properties, a clear understanding …

Energy Input-Output Meta-Analysis Reveals Algal Diesel Struggles To Break Even (Supplemental Information), Michelle Arnold

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1. Algal biofuels have been investigated as an alternative to traditional fossil fuels for transportation in the United States since the 1970s. Yet after five decades of development, scalability and implementation remain limited. To evaluate the state of progress, this study harmonized energy inputs and outputs across 39 papers, encompassing 508 observations on the production of algal biofuel energy return on energy investment (EROEI) in the United States. The analysis produced a mean EROEI of 1.01—essentially the break-even point—irrespective of system boundaries. This is lower than bioethanol (2.8) and far below oil (8.7). Life-cycle analysis results showed that hydrothermal liquefaction in …

Increasing Complexity Leads To Declining Productivity Of Innovation In The Algal Biofuel Industry (Supplemental Information), Michelle Arnold

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Liquid biofuels are widely promoted as renewable, lower-emission alternatives to fossil fuels. Yet despite their promise, this sector faces a critical constraint: a long-term decline in the productivity of innovation. This decline—measured by a decreasing number of patents per inventor—suggests that generating technological breakthroughs is becoming more difficult, expensive, and uncertain. As innovation becomes more resource-intensive, the feasibility of replacing petroleum with liquid biofuels grows more tenuous. This is especially problematic given the pre-existing technical disadvantages of biofuels, including their relatively low energy return on energy investment (EROEI) and energy density compared to fossil fuels. Our findings show that the …

A Gap Analysis Of The Legal Framework For Oil Spills : Management In Nigeria, Yetunde Ajoke Idris

World Maritime University Dissertations

No abstract provided.

Coal Phase-Out In The Silesian Coal Regions – Building Sustainable Scenario On Past Experiences, Adam Drobniak, Jan Bondaruk, Mirosław Skibski

Journal of Sustainable Mining

The dynamics of phasing out of hard coal mining are currently the subject of many debates and policies programming the energy transition. Diversity of opinions on the speed of the hard coal mining transition is evident. This discourse uses a number of technical, environmental, economic and social arguments that are not always supported by evidence-based analyses. As assumed in the European Green Deal, a responsible approach to decarbonisation requires just transition values. Thus, the negative effects of mining phasing out should be well recognized to enable their mitigation. This applies especially to the Silesian Voivodeship, where the concentration of so-called …

Response Characteristics Of Vegetation Ecology And Land Use Changes Tocoal Mining In Semi-Arid Regions, Du Zhen, Zhang Maosheng, Yun Shaoqi, Sun Pingping, Feng Li

Coal Geology & Exploration

Objective In semi-arid regions, intensive coal mining is prone to induce vegetation degradation and reshape the land use pattern. To identify the ecological impacts of coal mining and provide support for differential restoration, this study presents a quantitative comparison of changes in vegetation, soil moisture content, and land use types between mining-affected and non-mining areas.Methods Yulin City, Shaanxi Province was investigated in this study. Two parallel baseline frameworks were constructed: mining-affected and non-mining areas, which were compared under the sandy-fluvial terrace and loess hilly-gully landforms. The annual maximum normalized difference vegetation index (NDVI) derived from Landsat imagery was used …

Water Immersion-Induced Damage Mechanisms And Enhancement Via Nano-Modification For Artificial Dam Specimens With Vertical Interfaces, Li Yijia, Hao Xianjie, Chen Yuguang, Pang Tian, Yang Huaixiang, Li Hang, Ji Jinyi, Li Xinyu

Coal Geology & Exploration

Objective To accelerate ecological protection and high-quality development in the Yellow River basin, the concept of “conductivity, storage, and utilization” has been proposed to achieve the mine water storage and protection by transforming goafs into underground reservoirs and utilizing waterproof concrete dams. However, under the action of long-term water immersion and mining activity, the interfaces of composite concrete dam structures might undergo strength degradation, leading to hidden hazards. Methods By incorporating 0.5% and 1.0% nano-SiO₂, -Al₂O₃, and -TiO₂, this study prepared specimens with one vertical interface each that comprised double semi-cylinders through …

Risk Prediction Of Surface-Water Bursting In The Gully-Crossing Mining Section Of Shallow Coal Seams Within Thin Bedrock Zones, Niu Chao, Luo Yutao, Liu Ning, Xiao Lele, Sun Qiang, Zhang Weiwei, Xue Xicheng, Zeng Dabao, Bai Yang

Coal Geology & Exploration

Background The gully-crossing mining of shallow coal seams within thin bedrock zones is prone to connecting hydraulically conductive fracture zones in the overburden with surface water bodies, significantly increasing the risk of water disasters, such as water inrushes and surface-water bursting in mines. Some mining faces in the Shandong Coal Mine, Shaanxi Province are located beneath the Shajie Gully basin, where storm runoff is highly likely to flow into the underground mine through mining-induced fractures, posing a serious threat to mine safety. Therefore, there is an urgent need to research risk identification and assessment of surface-water bursting. Methods This study …

Influence Patterns Of Nanomaterials On The Properties Of Ultrafine Sulfoaluminate Cement, Li Xiaolin, Wang Pengfei, Gao Yinghui, Zhang Mingxuan, Dong Enyuan, Qu Yue, Zhao Yue

Coal Geology & Exploration

Objective and Methods This study aims to reduce the economic cost of sulfoaluminate cement-based grouting materials while also achieving excellent grouting reinforcement effects. To this end, it investigated the variation patterns of the compressive strength, setting time, and fluidity of the ultrafine fly ash (UFA)-ultrafine sulfoaluminate cement (USC) system by incorporating different dosages of silica fume (SF) and nano-silica (NS). Furthermore, the mechanisms behind the hydration reactions of the system were explored. Using multiple distinct testing techniques such as X-ray diffraction (XRD) mineralogy, Fourier transform infrared spectroscopy (FTIR), thermogravimetric-differential thermal analysis (TG-DTA), and scanning electron microscopy (SEM), this study analyzed …

Structural Characteristics Of The Overburden And Water Yield Property Of Weathered Bedrock Aquifer In A Representative Medium-Deep Coal Seam, Wang Lu, Hua Zhaolai, Huang Hao, Li Zenglin, Ren Shuaifeng, Wang Sitong

Coal Geology & Exploration

Background The weathered bedrock aquifer represents a major water-filled aquifer encountered during coal mining in the Jurassic coalfield in northern Shaanxi Province. Therefore, evaluating the water yield property of the weathered bedrock aquifer is the key to the prevention and control of water hazards in coal seam roofs. Methods This study investigated panel 12 of the Caojiatan Coal Mine, Shaanxi Province. Analysis of the stratigraphic and lithological structure types of the overburden of coal seam 2^–2 identified the weathered bedrock as the primary overlying water-bearing aquifer of the coal seam. Using net-to-gross (NTG) ratio, sandstone thickness, weathering influence index, …

Numerical Simulations Of The Overburden Stability In Underfilling Zones During Continuous Mining And Continuous Backfilling Of Coal Mines, Liu Lang, Luo Yixiao, Zhu Mengbo, He Jun, Qu Huisheng, Duan Huaijun, Wei Baoning, Liu Zhizhen

Coal Geology & Exploration

Objective and Method Coals serve as a predominant energy source in China. However, coal mining has resulted in increasingly pronounced ecological issues such as ground subsidence and solid waste accumulation. Although the continuous mining and continuous backfilling (CMCB) technology allows for efficient resource recovery and ecological protection through backfilling with coal-based solid waste, the issue of insufficient roof-contact backfilling (termed underfilling) poses a serious threat to the overburden stability during mining. Given the unclear mechanisms behind the influence of coupled multiple factors of underfilling zones in current research, this study constructed three-dimensional numerical models using the 3DEC discrete element software …

An Experimental Study On The Breakthrough Pressure Of Different Co2 Phases Against Cap Rocks For Carbon Storage In Saline Aquifers, Dan Wendong, Li Yi, Wang Fugang, Hu Zhikai, Diao Yujie, Ma Xin, Liu Ting

Coal Geology & Exploration

Objective CO₂ breakthrough pressure, a core parameter for characterizing the sealing performance of saline aquifers as cap rocks, holds important scientific significance and application value for ensuring the safety of CO₂ geological storage engineering and assessing its storage potential. However, there is a lack of systematic studies on the variation patterns and mechanisms of breakthrough pressure under different occurrence phases of CO₂ (supercritical, liquid, and gaseous) currently. Accordingly, universal and reliable conclusions are yet to be reached. Methods This study conducted experiments on a natural low-permeability unsaturated sandstone core. Using the step-by-step method, 13 groups of breakthrough …

Characteristics And Driving Forces Of The Spatiotemporal Evolution Of Surface Water Bodies In Ecologically Fragile Mining Areas In The Yellow River Basin: A Case Study Of The Yushenfu Mining Area, Chen Chao, Xuan Ang, Hu Zhenqi, Wang Yiming, Zhang Jiachao, Wang Guo, Yang Fuqin

Coal Geology & Exploration

Background This study aims to respond to the strategic demand for ecological protection and high-quality development in the Yellow River basin. To this end, research on the characteristics and driving forces of the spatiotemporal evolution of surface water bodies under the disturbance of intensive coal mining serves as the basis and a prerequisite for mitigating the contradiction between coal mining and water resources in ecologically fragile mining areas of the Yellow River basin. Methods Based on 10 stages of remote sensing image data from 1980 to 2023, information about surface water bodies in the Yushenfu mining area was extracted using …

Compressive Deformations And Energy Dissipation Characteristics Of Broken Rock Masses Under Lateral Confinement, Tian Yu, Lin Haifei, Li Shugang, Shuang Haiqing, Xu Peiyun, Liu Sibo, Ji Pengfei, Cui Mingwei

Coal Geology & Exploration

Objective This study aims to investigate the deformation and energy dissipation characteristics of broken rock masses in the caving zones of goafs during compression and to reveal their impacts on the movement and failure of overlying strata and surface subsidence. Using a self-developed experimental system, this study conducted compression experiments on broken rock masses under lateral confinement under different Talbot index values and axial stresses. Then, it analyzed variations in axial displacement, void ratio, relative breakage index, fractal dimension, and strain energy density of the broken rock masses during compression. Accordingly, this study quantified variation patterns of strain energy density …

Mechanisms And Risk Criteria For Water Inrushes Caused By Mining-Induced Propagation Of Concealed Faults In A Coal Seam Floor, Zhang Wenquan, Shao Jianli, Shi Junwei, Li Liangning

Coal Geology & Exploration

Background Concealed faults in a coal seam floor, characterized by random distribution, are prone to induce water inrushes, which are difficult to prevent and control. Objective and Method This study aims to investigate the mechanisms behind water inrushes induced by concealed faults in a coal seam floor under the influence of coal mining. Through a theoretical analysis, this study established the mechanical models of the initial cracking and wing crack propagation of concealed faults under seepage pressure. By analyzing the maximum propagation height of concealed faults in the floor and the post-propagation safe thickness of aquicludes, this study proposed criteria …

Overview And Prospects Of Plain Reservoir Construction And Utilization In Coal Mining-Induced Subsidence Areas With High Water Tables In The Lower Reaches Of The Yellow River, Chen Shaojie, Jiang Ning, Zhang Genwang, Jiang Chunlin, Gao Qun

Coal Geology & Exploration

Background Coal mining-induced subsidence areas with high water tables in the lower reaches of the Yellow River are encountered with pronounced contradictions between large-area water accumulation and issues including urban water scarcity, groundwater contamination, ecological degradation, and low farmland reclamation rates. These contradictions severely restrict the green, low-carbon transformation of cities with coal mines and hinder the high-quality development of the Yellow River basin. This study aims to explore the construction of plain reservoirs in these subsidence areas as a critical approach to the intensive utilization of water and land resources in the subsidence areas, as well as the ecological …

Discussion On Multi-Sphere Responses And Damage Reduction-Oriented Geological Guarantees In Coal Mining, Wang Shuangming, Sun Qiang, Li Shibo, Hu Xin, Gu Chao, Geng Jishi, Zhou Shutao, Yuan Shihao, Song Shijie, Niu Chao, Wu Yun, Chen Yang

Coal Geology & Exploration

Objective Coals serve as a cornerstone for ensuring the energy security of China. However, coal mining activities break the original in situ stress equilibrium, triggering multi-sphere damage conduction and coupling responses in the lithosphere, hydrosphere, pedosphere, biosphere, and atmosphere from underground to the surface, involving rock mass structure, groundwater, and surface environment. Consequently, the original structural relationships, occurring elements, and functions of these spheres will be changed. Presently, investigating the multi-sphere structural evolution, conservation, and utilization in coal mining to underpin the role of coals as an energy cornerstone is significant for resolving the contradiction between the high-quality development of …

Table Of Contents, The Editors

Coal Geology & Exploration

No abstract provided.

Influence Mechanisms Of Soil Layer Reconstruction And Fungal Inoculation On Plant Water Use In Waste Dumps, Bi Yinli, Li Zhongqing, Ke Zengming, Peng Suping

Coal Geology & Exploration

Objective In the mining areas of open-pit coal mines in the arid and semi-arid regions in western China, water scarcity severely restricts ecological restoration. As preliminary ecological effects have been achieved through soil layer reconstruction and bioremediation-based reclamation technologies in waste dumps of the mining areas, there is an urgent need to investigate the effects of both technologies on the water use and growth of representative plants. This will provide a scientific basis for accelerating ecological restoration in the mining areas. Methods In a waste dump of the Heidaigou open-pit coal mine in Inner Mongolia, four experimental program for soil …

Influence Patterns Of Coal Mining-Induced Subsidence On Economic Losses From Soil Erosion Of Loess Slopes In The Middle Reaches Of The Yellow River, Song Shijie, Li Yuanhong, Wang Yi, Liu Lu, Tian Yu, Tan Qingyu

Coal Geology & Exploration

Background Quantitative assessment of economic losses from soil erosion on subsidence slopes in coal mining-induced subsidence areas can offer a critical basis for formulating scientific economic compensation standards while also laying a solid foundation for efficient governance.Methods This study investigated the subsidence slopes with different morphologies in the typical loess area subjected to coal mining-induced subsidence in northern Shaanxi Province. Using methods including field sampling, laboratory tests, and environmental economics analysis, this study constructed an index system for the quantitative assessment of economic losses from soil erosion on coal mining-induced subsidence slopes and revealed the variation patterns of such …

Mechanisms Behind Consolidation-Induced Water Release From Effective Impermeable Soil Layers And Mine Water Inflow Prediction In Coal Mining, Li Tao, Gao Ying, Fan Limin, Yang Junwei

Coal Geology & Exploration

Background In the Yushen mining area, coal mining is gradually shifting toward areas with thick soil layers. This leads to continuous water release from the saturated soils above the hydraulically conductive fracture zones, thereby significantly increasing the burden of mine water drainage. Focusing on the Yushuwan Coal Mine in northern Shaanxi, this study investigated the mechanisms behind mining-induced water release from effective impermeable soil layers and predicted mine water inflow. Methods Using conventional hydrochemistry, isotopic hydrochemistry, and a high-throughput microbial sequencing method, this study conducted qualitative and quantitative identification of the primary water sources of a mine in the Yushuwan …

Numerical Simulations Of The Influence Of Vegetation Configuration On Dust Migration In Open-Pit Coal Mines, Han Li, Li Renjie, Bi Yinli

Coal Geology & Exploration

Background Dust pollution emerges as a major environmental challenge in the open-pit mining of coal mines. Ecological restoration has found widespread applications in mining areas as a crucial measure. However, there is a lack of systematic studies on the role of vegetation configuration in dust migration. Methods Using the computational fluid dynamics (CFD) method for numerical simulation, this study constructed a comprehensive simulation framework incorporating wind field reconstruction, dust migration, and the dust retention capacity of vegetation. By setting different particle sizes and wind speeds, this study systematically analyzed dust migration patterns. Furthermore, vegetation configuration was introduced into the simulation …

Links Of Intensification Chemical Weathering And Nickel Enrichment With Volcanism In The North China Plate Around The Permian-Triassic Boundary, Wang Ye, Ye Chengzhuo, Zhang Tong, Yang Minfang, Zhou Kai, Zhang Peixin, Yang Yuzhu, Zhang Chu, Lu Jing

Coal Geology & Exploration

Objective The North China Plate serves as a pivotal region for deciphering the mechanisms underlying the links of volcanism and paleoenvironmental-climatic upheavals around the Permian-Triassic Boundary (PTB). The dramatic environmental perturbations during this period are closely linked to large-scale volcanic eruptions of the Siberian Traps Large Igneous Province (STLIP). These eruptions triggered global warming, extreme chemical weathering events, and mass extinctions, marking a significant turning point in the evolution of the Earth system.Methods This study investigated the Sunjiagou and Liujiagou formations in the WY-U-01H borehole in the Qinshui Basin, North China Plate. Using the chemical index of alteration (CIA), …

Mechanisms Underlying The Impacts Of Reservoir Pore Structures On Near-Well Salt Precipitation In Co2 Geological Storage, Deng Chenguang, Sun Xiaolong, Liu Keyu, An Senyou, Yuan Guanghui, Wang Yuxiang

Coal Geology & Exploration

Objective and Method High CO₂ injectivity in reservoirs is essential for high-quality sites of CO₂ geological storage (CGS). Salt precipitation in the vicinity of injection wells due to brine dissolution in CO₂ emerges as a critical factor impairing CO₂ injectivity. To explore the differences in the mechanisms behind salt precipitation and damage degree across various reservoirs, this study conducted salt precipitation simulation experiments on sandstone samples with distinct pore structures using a high-temperature and high-pressure fluid displacement system. By combining methods such as cast thin section observations, scanning electron microscopy and resulting spectra, micro-X-ray fluorescence (micro-XRF) …

Building And Geological Interpretation Of A 3d Resistivity Model For The Reclamation Area Of The Jiaozhou Bay, Yu Peng, Zhao Mingyue, Yang Haiyan, Li Wenyu, Tian Jian, Yan Houzhen, Zhang Chao

Coal Geology & Exploration

Background With the advancement in smart city construction in China, the development and utilization of urban underground space have become a focal point. Geophysical methods, as a crucial technical means for underground geological structure exploration, face new challenges when applied to complex exploration environments in urban areas. Objectives and Methods To address issues in underground space exploration in the coastal area of Qingdao, this study investigated the reclamation area along the eastern coast of the Jiaozhou Bay. Using a detection technique that combined the transient electromagnetic method (TEM) using a conical source and high-density resistivity method, this study constructed a …

A Method For Detecting Weathered And Oxidized Zones In Shallowly Buried Coal Seams Integrating Logging And Dense Microtremor Array Technology, Ma Zhi, He Weisheng, Hu Qiuping, Guo Zhengxue, Zhou Jinju, Chen Tongjun, Yang Le, Yuan Zhichao

Coal Geology & Exploration

Objective The central and western regions of China hold abundant shallowly buried coal resources. However, the accurate exploration and safe, efficient development of coal seams in these regions are confronted with serious challenges due to weathering and oxidation. To achieve the cost-effective delineation of weathered and oxidized zones in shallowly buried coal seams, this study proposed a novel exploration method that integrated logging and dense microtremor array technology based on differences in physical properties and geophysical responses between weathered and oxidized zones and normal strata. Methods Initially, based on the analysis of the laws of variations in the physical properties …

Global Representative Metallogenic Models And Geophysical Exploration Methods Of Sylvite: Current Research Status And Prospects, Qu Ping, Yue Hangyu, Huang Xiaobing, Song Jiong

Coal Geology & Exploration

Background Sylvite serves as a strategic mineral resource that plays a significant role in ensuring food safety and sustainable agricultural development, with approximately 90% of global potash resources used for potassium fertilizer production. However, developing countries such as China have long faced the challenges of heavy dependence on potash imports and insufficient potash resource continuity. Such a supply and demand framework causes China to speed up research on potash metallogenic patterns and technical innovations in potash exploration. This will help overcome resource bottlenecks. Objective This study presented a systematic summary of global potash metallogenic models and investigated the approaches of …

A Rock Engineering System Model For Predicting Fragment Size Of Muck-Pile Using Geometric Parameters And Rock Mass Properties, Patrick Adeniyi Adesida, Victor Abioye Akinbinu, Babatunde Adebayo

Journal of Sustainable Mining

This study aimed to evaluate rock fragmentation risk indexes and develop a predictive model for the median size of fragment (X₅₀) using the Rock Engineering System (RES). The methodology includes the analysis of 15 significant parameters of rock properties and blast design, which are considered to be important to rock fragmentation from 30 selected blast sites. These parameters include rock type, hardness, blast-hole diameter, charge weight, blast pattern, and others that control fragmentation results. Statistical analysis was performed to validate the RES-based model developed from these parameters. The model exhibited a strong predictive capacity, evidenced by a …

Empirical Methods For Support System Design In Deep Serpentinite Excavations: A Critical Evaluation, Anas Driouch, Redouane Oubah, Abdelaziz Lahmili, Latifa Ouadif

Journal of Sustainable Mining

Underground mining excavations in fragile serpentinite rock masses represent a significant challenge today. The complicated features of these rock formations, especially at great depths, make it difficult to classify them using commonly employed methods. This paper focuses on the application of empirical methods for the classification of serpentinite rock masses and the design of support systems in underground mining excavations. Specifically, it concerns an access tunnel excavated entirely in serpentinite at a depth of 460 m. Geomechanical classification systems indicate that the Tunnelling Quality Index (Q-system) and Rock Mass Rating (RMR) evaluate serpentinites as rock masses of exceptionally poor to …

How Eppley Airfield Could Be Reducing Your Power Bill (But They’Re Not), Cherry Pham

Op-Eds from ENSC230 Energy and the Environment: Economics and Policies

Eppley Airfield in Nebraska is spending $950 million on their renovation and services are still running, even during construction. Part of the airport’s renovation budget could be allotted to installing solar canopies. In the long run, airports with solar canopies reduces their own electricity expenses.