Digital Commons Network^™

Developing A Framework For Mooc Dropout: The Role Of Utilitarian And Hedonic Values In Student Retention, Bipllab Roy, Mave D'Souza, Madhura Laghane

Northeast Journal of Complex Systems (NEJCS)

Massive Open Online Courses (MOOCs) have expanded access to higher education but continue to face persistently high dropout rates, raising concerns about their long‑term effectiveness and sustainability. This study develops and empirically tests a structural framework that links utilitarian values (perceived usefulness, certificate value, time flexibility), hedonic values (enjoyment, variety and novelty, personal interest alignment), and individual characteristics (goal orientation, self‑efficacy, motivation type) to MOOC student retention. Data were collected through a structured questionnaire administered to 200 MOOC learners from Christ University, Lavasa Campus, and analyzed using Structural Equation Modelling (SEM) in AMOS. The results show that goal orientation, self‑efficacy …

Engineering: What Are We Doing?, Matthew Kuperus Heun

University Faculty Publications and Creative Works

Keynote speech at 2026 Christian Engineering Society Conference and 2026 Association for Christians in Mathematical Sciences Conference

Du Undergraduate Showcase Abstracts: Research, Scholarship, And Creative Works, Sophia Wismar, Henry Staats, Allison Metzler, Chloe Puckett, Rachel Levine, Christa Kilpatrick, Scott Wolf, Joe Walsh, Grace Doolittle, John Engebreston, Zoe Lopez, Christopher Aaby, Audrey Duff, Timothy Sisk, Katelyn Lamberton, Angela Narayan, Gilkah Argueta, Habiba Samir, Girena Tesfazghi, Genet Kenore, Sinit Tesfamariam, Effley Brooks, Abi Newell, Megan Doherty, Natalie Baer, Lexi Blood, Talya Riciputi, Jessica Jimenez, Devin Hernandez, Lynn Clark, Taj Kumar, Sunil Kumar, Allen Rutman, Mira Pronobis, Tess Carson, Anna Sher, Frankie Stroud, Tamra Pearson D'Estree, Alyssa Wilson, Emily Melnick, Jenalee Doom, Yihang Gao, Gwendolyn Geiger, Noah Gettle, Scott Nichols, Clare Ayoub, Cara Dienno, Sunny Walker, Zoe Hansen, Maya Wheeler, Addison Rice, Patrick Martin, Sanjana Acharya, Daniel Mcintosh, Amanda Mckellips, Calli Cain, Justin Blake, Peter Sokol-Hessner, Natalie Miller, Max Weisbuch, Sophia Dellota, John Macikas, Charlotte Snow, Mark Siemens, Zoe Lynch, Alex Huffman, Prachi Shah, Jason Roney, Halcyon Levi, Nicole Herzog, Andrea Koly, Daniel Linseman, Annie London, Xi Yang, Avery Zwisler, Jane Smith, Chaz Contag, Michael Kerwin, Lucy Rand, Grace Schroeder, Michelle Rozenman, Nissa Tapper, Guiming Zhang, Mateo Mazariego-Halpern, Keith Meyer, Julie Do, Dakota Park-Ozee, Travis Herink, Kara Neu, Jonathan Plomin, Eve-Odine Duchaufour, Debbie Gale Mitchell, Tennyson Anderson-Stricklin, Lily Treitz, Samantha Rosenberger, Sierra Griffith, Finley Joseph, Daniel Sampson, Emmy Davis, Skyler Kasnoff, Evon Lopez, Vivian Nguyen, Cassy Young, Franklin Sellner, Martin Tobon, Ila Graham, Zach Billings, Holden Hedit, Decatur Boland, Paul Kosempel, Cory Chandler, Jay Mahoney, Sam Dragan, Susan Dagget, Yarrow Ator, Heidi Vuletich, Owen Weber, Andrew Kloeppel, Petersen Gray, Mandi Schaeffer-Fry, Razleen Bassra, Bryanna Rodriguez, Christina Blue, Taubie Sanders, Rachel Epstein, Luke Milburn, Camryn Evans, Ezra Martinez, Mary Westwood, Gabri Notov, Robin Tinghitella, Lilou Cabrol, Eli Barbour, Juliet Mendik, Selma Myers, Zac Wise, Noah Fahlin, Michelle Knowles, Abigail Hopper, Michael Greenberger, Romi Laclair, Sarah Watamura, Sabrina Efroymson, Casey Barker, Sydney Seltzer, Bryn Yehle, Jennifer Hoffman, Sara Garcia, Ryuka Nagamine, Trevor Briggs, Remy Le Boeuf, Elena Krone, Eileen Farrell, Regan O'Rourke, Elena Roel, Greg Mortimer, Ali Ayoub, Stefani Langehennig, Caitlin Turk, Logan Scmid, Stefan Chavez-Norgaard, Karen Kim, Tatiana Peccedi, Courtney Cassidy, John Sebesta, Rhianna Lewis, Janice Bening-Lacek, Vivian Lawless, Mckenna Hanson, Jeffrey Amidon, Riya Joshi, Ram Ambre, Brady Worrell, Perrin Schneider, Ali Azadani, Brooke Agulnek, Lyndsie Salvagio, Elise Siemanowki, Yan Qin, Andre Allen, Melodie Nguyen, Megan Livengood, Abby Reams, Saffron Hartreeve, Bri Wylie, Sarah Brookman, Mariah Loiacono, Green Russo, Abhia Lodhi, Gabrielle Welsh, Nika Spehar, Shahked Levin, Evrim Baykal, Kimberly Chiew, Jocelyn Torres, Kailey Hicks, Mykaela Tanino-Springsteen, Audrey Bellows, Akam Chahal, Madeline Tepper, Shannon Murphy, Alexa Fonseca, Deborah Han, Cassandra Perez, Oluwatoyin Alaba, Julia Roncoroni, Vy Nguyen, Nana Burn, Sarah Sasse, Rubin Tuder, Anthony Gerber, Nancy Lorenzon, Christine Vohwinkel, Camryn Gunter, Tristan Weber, Sam Rommel, Brian Michel, Muskan Fatima, Alannah Oleson, Kira Frey, Edward Garrido, Beckett Morris, Kerstin Haring, Drew Middleton, Abigail Walpert, Liam Dee, Gabby Ishaw, Cole Carnes, Maddie Weiser, Claire Fox, Valeriia Vlasenko, Kateri Mcrae, Riley Smith, Abigail Templin, Kushani Rajapaksha

DU Undergraduate Research Journal Archive

Abstracts from the DU Undergraduate Research Showcase.

Modulating Electronic Structure With Linearly Fused Pyrazine Units For High-Voltage And Stable Zinc-Organic Batteries Cathode, Min-Jian Zhao, Li-Bin Zhang, Jin-Tao Wang, Kun Ding, Hai-Mei Liu, Yong-Gang Wang

Journal of Electrochemistry

High-voltage n-type organic cathode materials are critical for constructing zinc-organic batteries (ZOBs) with high energy density and long cycle life. However, the intrinsically unfavorable electronic structures and relatively high LUMO energy levels of most n-type materials often lead to sluggish kinetics, high solubility, and suboptimal discharge voltages (< 0.8 V). Here, we design a small molecule, quinoxalino[2’,3’:5,6]pyrazino[2,3-f][1,10]phenanthroline (DPQP), as a ZOB cathode by introducing locally electron-deficient motifs into the conjugated backbone of aromatic compounds. The linearly fused pyrazine units extending the pyrazine–benzene framework effectively optimize the electronic structure, thereby significantly enhancing the discharge voltage. Meanwhile, the expanded π-conjugated plane suppresses dissolution and accelerates charge-transfer kinetics. Benefiting from these features, the DPQP electrode exhibits an exceptional increase in average operating voltage from 0.61 V to 1.07 V (vs. Zn²⁺/Zn) at 0.1 A·g^–1, with an overpotential of only 140 mV. Notably, no discernible voltage decay occurs as the current density increases, indicating rapid and highly reversible redox kinetics. Furthermore, the DPQP cathode delivers outstanding cycling stability, maintaining over 2000 h of continuous operation at 0.1 A·g^{–1 …}

(Co,Ni,Mn,Cu,Zn)O High-Entropy Oxide Nanotubes As Efficient Bifunctional Electrocatalyst For Oxygen Evolution And Hydrazine Oxidation Reactions, Pan-Yan Chen, Wan-Wan Wu, Heng Bian, Wei-Wei Li, Xin-Sheng Zhao, Lu Wei

Journal of Electrochemistry

High-entropy oxides (HEOs) present significant scientific challenges in both design and synthesis due to their multielement and high-entropy nature, which involves complex combinations of multiple metal cations and oxygen anions, typically arranged in equimolar ratios to achieve structural stability. Herein, one-dimensional (Co,Ni,Mn,Cu,Zn)O high-entropy oxide nanotubes (HEO-NTs) are fabricated by means of a gradient electrospinning strategy with a tailored polyvinyl alcohol (PVA) molecular weight distribution and controlled pyrolysis. Benefiting from the HEO features and the synergistic effect of multicomponent sites, the as-synthesized (Co,Ni,Mn,Cu,Zn)O HEO-NTs exhibit exceptional bifunctional electrocatalytic activity for the oxygen evolution and hydrazine oxidation reactions (OER/HzOR). This study offers …

A Faith And Technology Resource Hub: Building The Christian Engineer’S Bookshelf, Gayle Ermer, Derek Schuurman

University Faculty Publications and Creative Works

A wealth of material related to the interactions between faith and technology has been generated over time to help Christian engineers reflect on and evaluate their work and technology development more generally. However, there is currently no central location where this large variety of resources can easily be accessed. This paper will describe the process of developing a faith and technology resource hub. The vision for the hub is that it will include a comprehensive searchable directory of resources addressing faith and technology, as well as a browsable, organized, curated, and annotated set of webpages containing links to particularly important …

A Distinctly Christian Understanding Of The Technical Details In Engineering, Paul Griffioen

Faculty Work Comprehensive List

Within engineering disciplines, much attention has been given to developing pedagogical techniques and practical applications that are distinctly Christian. However, not as much attention has been given to understanding technical engineering content from a distinctly Christian perspective. The main reason is that the technical details of engineering seem to be the same for both Christians and non-Christians. After all, does being a Christian have any impact on the content of specific technical details like integration and finite element analysis? Since the vast majority of time in engineering jobs, research, and teaching is spent on specific technical details, this is a …

An Ai-Integrated Methodology For Secure Software And System Development, Ian Matthew Campbell Coston

Electronic Theses and Dissertations 2020 - Present

Securing interconnected software systems requires more than layering existing frameworks on top of each other. Most current Secure Software and System Development Lifecycle (S-SDLC) models treat security as a phase rather than a design condition, leaving real gaps in governance, access control, and automated enforcement that become critical failure points in Internet of Things (IoT) environments where devices are resource-constrained, long-lived, and frequently insecure by default.

This dissertation introduces the Automated Zero Trust Risk Management with DevSecOps Integration (AZTRM-D) methodology, a novel approach that unifies DevSecOps automation, the National Institute of Standards and Technology (NIST) Risk Management Framework (RMF), and …

Evaluating Soil Health And Crop Yield In Louisiana Agricultural Systems: Impacts Of Best Management Practices And Prediction Models, Hector J. Mendoza Lagos

LSU Doctoral Dissertations

The adoption of conservation management practices is critical for improving soil health, enhancing nutrient use efficiency, and sustaining crop productivity in row crop systems in Louisiana. This study evaluated the role of conservation agronomic practices, soil biochemical indicators, and machine learning predictive models to improve soil nutrient dynamics, soil health indicators, microbial communities (MC), and crop productivity on a corn (Zea mays L.) research plot scale and in a commercial forty-hectare cotton (Gassypium hirsutum L.)-corn-soybean (Glycine max L.) rotation system in northeast Louisiana. The objectives of the study were to evaluate soil nutrient dynamics and MCs under …

Measuring Stock Market Inefficiency Using A Multilayer Composite Efficiency Index: A Case Of The Egyptian Exchange, Patrick K. Owido, Hiroki Sayama

Northeast Journal of Complex Systems (NEJCS)

Financial markets play a critical role in resource allocation. Their performance depends on the decisions of millions of independent investors constantly reacting to one another. Their informational efficiency remains a subject of debate across economic systems. When informational efficiency is present at the weak form, historical price information should not consistently predict future returns. Several empirical tests of this hypothesis often focus on the behavior of aggregate market indices, and use individual efficiency proxies such as autocorrelation, GARCH-type volatility, or entropy-based measures to measure efficiency. This has often yielded mixed results, particularly in emerging markets. Here we show that testing …

High-Throughput Robotic Ethanol Inhibition Assays For Engineered Thermophilic Biofuel Strains, Kevin He, Daniel Olson, Marybeth Maloney, Anthony Lanahan

Wetterhahn Science Symposium Posters

Ethanol stress assays are commonly used to evaluate microbial tolerance, metabolic adaptation, and fermentation performance. However, manual liquid handling introduces variability across replicate wells and small-volume pipetting steps, limiting reproducibility and throughput. This study developed an automated OT-2 robotic workflow to generate replicated ethanol concentration gradients for high-throughput inhibition assays in engineered thermophilic biofuel strains. Kinetic plate-reader measurements were used to quantify ethanol-dependent growth responses under anaerobic fermentation conditions. The reasearch question is: How do engineered thermophilic biofuel strains differ in ethanol-dependent growth inhibition under anaerobic fermentation conditions, and can automated robotic assays improve the reproducibility of these measurements? Can …

Wake-On-Anomaly Federated Architecture For Privacy-Preserving Poultry Health Early Warning, Mahmoud Aziz Louati

Masters Theses

Highly pathogenic avian influenza outbreaks, respiratory disease, heat stress, and silent equipment failures share one operational reality: they are detected too late because today’s poultry-health workflow is reactive, manual, and dependent on producers volunteering commercially sensitive data. This thesis presents a wake-on-anomaly federated architecture that addresses both the detection-latency problem and the privacy–adoption deadlock that has so far prevented cross-farm collaboration. The architecture is organized in two tiers. Tier 1 is a lightweight LSTM autoencoder that continuously screens four routine telemetry channels (water, feed, house temperature, activity proxy) and emits a per-window reconstruction-error score. A debounced k-of-m trigger with cooldown …

Isometric Force Characterization Of Braided Pneumatic Actuators, Ben Bolen, Mohammad Elzein, Lawrence Pang, Alexander Hunt

Mechanical and Materials Engineering Faculty Publications and Presentations

Artificial muscles such as braided pneumatic actuators (BPAs) offer many advantages for robotic systems, including high durability and strength-to-weight ratios. However, their use in robotic systems is still extremely limited, in part due to their poor force, length, and pressure characterization. In this work, a test setup is created to compare force produced by Festo fluidic BPAs with leading models. Our analysis of the data has resulted in (1) the development of new equations to calculate force as functions of pressure and contraction for Festo BPAs with uninflated diameters of 10 mm and 20 mm, and (2) a novel equation …

On Some Properties Of Generalised Regular Anti-Topological Space, Bhimraj Basumatary, Gugu Narzary, Jeevan Krishna Khaklary

Neutrosophic Systems with Applications

This article studies Regular Anti-open sets and Generalised Regular Anti-open sets within a topological framework, addressing the limited development of anti-open structures in generalised topology. We introduce Regular Anti-open sets and establish their fundamental properties. The study is extended by defining Generalised Regular Anti-open sets, providing a broader and more flexible class of sets. Furthermore, the notions of GR-interior and GR-closure are introduced and analyzed, and their essential properties are obtained. The results contribute to a clearer understanding of generalized anti-open structures and provide a basis for further research in topology.

Classes Of Analytic Functions Defined By Salagean Derivative Operator Associated With Neutrosophic Generalized Poisson Distribution, Soliu O. Opeyemi Okunola, Olushola Adeyemo, Sayo A. Abidemi Gbangbala, Folorunso I. Isola Akinwale

Neutrosophic Systems with Applications

This study introduces and analyses new subclasses of analytic functions by applying the Salagean derivative operator to the Neutrosophic Generalized Poisson Distribution (NGPD) series. We develop a model where the mean parameter is treated as an interval or set to account for indeterminacy in complex systems. By employing Stirling numbers of the second kind and decreasing factorials, we derive necessary and sufficient coefficient inequalities and inclusion relations for these new subclasses. Numerical results and graphical illustrations demonstrate the sensitivity of these functions to orientation and the neutrosophic parameter, providing a framework for applications in fields like medical imaging and network …

Enhanced Population Mean Estimation Using An Exponential Estimator With Known Medians Of Dual Auxiliary Variables Within A Neutrosophic Approach: Applications In Agricultural Yield Prediction, Anchal Yadav, Mukesh Kumar

Neutrosophic Systems with Applications

In classical statistical theory, estimation of population parameters is generally carried out under the assumption that all observed data are precise, complete, and free from ambiguity. However, in many practical and real-world situations, data often deviate from these ideal conditions and instead appear in vague, uncertain, or interval-valued forms. Such imperfections reduce the effectiveness of traditional estimation techniques and motivate the development of more flexible and robust methodologies. To address these challenges, several improved estimators, particularly neutrosophic ratio-type estimators and their advanced extensions, have been proposed in recent literature. In this study, a new estimator known as the two auxiliary …

Optimization Of A Multi-Item Supply Chain Model With Shortages Under Parametric Type-2 Interval Environments, Sourav Kumar Kumar Giri, Totan Garai, Sahidul Islam, Haridas Mondal, Shariful Alam

Neutrosophic Systems with Applications

Modern supply chain systems frequently operate in environments where demand, costs and inventory-related parameters are uncertain and difficult to estimate accurately. These uncertainties become more critical in multi-objective decision-making situations, where decision makers must simultaneously balance several conflicting goals. Conventional optimization techniques often fail to represent the ambiguity and vagueness present in practical decision environments. To overcome these limitations, this study develops a multi-item supply chain model for a single supplier and a single buyer by incorporating Type-2 interval representations into the modelling framework. The proposed approach introduces a structured set of arithmetic operations for Type-2 intervals to manage uncertain …

A Goal Programming Approach For Finding The Best Compromise Solution Of Multiobjective Linear Programming Under Neutrosophic Environment, Sultan S. Alodhaibi, Hamiden Abd El- Wahed Khalifa

Neutrosophic Systems with Applications

Decision problems often involve multiple objectives that conflict, making simultaneous optimization impossible. These problems require trade-offs to achieve a solution that balances the competing goals. In this paper, the detailed discussion that is related to linear programming (SVTrNFMOLP) with single valued trapezoidal neutrosophic numbers is made. Furthermore, this study deals with all the related parameters and discussion. As rank function and due to its definition, the SVTrNFMOLP is transformed in the crisp MOLP. It is noticed that goal programming is best to get the best compromise solution. The advantages of the proposed approach are: The use of Tr allows the …

Mining And Sustainable Development In Sierra Leone: The Role Of Institutional Quality, Ibrahim Massaquoi

Journal of Sustainable Mining

While mining can drive economic growth, create jobs, and promote infrastructural development, it also poses risks to the environment, human health, and social well-being. Therefore, to achieve sustainable development, responsible mining is crucial. This study empirically examines the role of institutional quality in the mining-sustainable development nexus in Sierra Leone. With the use of the planetary pressures-adjusted human development index (PHDI) as a comprehensive measure of sustainable development, the study is able to integrate economic, social, and environmental dimensions. The autoregressive distributed lag (ARDL) model confirms the existence of both short-run and long-run dynamics. The results of the study show …

Geological Environment’S Dynamic Responses And Damage Reduction-Oriented Geological Guarantee In Coal In-Situ Conversion, Wang Shuangming, Geng Jishi, Sun Qiang, Shi Qingmin, Liu Lang, Wang Shengquan, Yang Yuru, Yuan Shihao, Zhang He, Hu Xin

Coal Geology & Exploration

Objective Coal in-situ conversion (ISC) emerges as an important transformative technology for clean and efficient utilization of coal resources. However, safe and stable coal ISC is currently restricted by two major bottlenecks: an unclear understanding of the mechanisms underlying the geological environment’s dynamic responses and a lack of damage reduction-oriented geological guarantee. Methods To construct a damage reduction-oriented geological guarantee system for safe and green coal ISC, this study, from the perspective of the geological environment’s dynamic responses throughout coal ISC, elucidates the scientific connotations of both the dynamic responses and the geological guarantee in coal ISC. Based on the …

Theory And Key Technologies Of Collaborative Management And Control For Groundwater Protection, Treatment, And Utilization In Coal Mining Areas, Dong Shuning, Wang Hao, Guo Xiaoming, Dong Xingling, Qiao Wei, Wang Xiaodong, Zhang Xiyu, Zhang Wenzhong, Zhu Kaipeng, Hu Yunhao, Zhou Zhenfang, Duan Jianhua, Miao Hechao, Wang Tiantian, Wang Hai, Xue Jiankun

Coal Geology & Exploration

Background and Methods To mitigate the contradiction between abundant coal resources and scarce water resources in China, this study proposes a collaborative management and control solution for groundwater protection, treatment, and utilization in coal mining areas. From a theoretical perspective, this study investigates the propagation chains of both the coal mining disturbance to groundwater and the responses of groundwater systems to engineering interventions. Furthermore, it elucidates the core idea, scientific connotation, and technical architecture of the collaborative management and control and explores key technologies involved. Results and Conclusions A technical system based on accurate prediction and precise monitoring, covering treatment-protection …

A Review Of Full-Lifecycle Management Practices For Blue Mining Centered On Sustainable Development And Resource Efficiency, Hou Zhengmeng, Zhang Shengyou, Chen Qianjun, Sun Wei, Zhang Tian, Cai Nan, Huang Liangchao, Wang Qichen, Shi Tianle, Xu Xiaochuan

Coal Geology & Exploration

Against the backdrop of China’s goals of peak carbon dioxide emissions and carbon neutrality, along with the growing demand for critical minerals, this study presents a systematic review of domestic and international literature and engineering cases. Based on the Blue Mining concept proposed by Langefeld’s team of the Clausthal University of Technology and from the perspective of planning forward, this study organizes key technologies, treatment pathways, and essentials of full-lifecycle management used to transition mines from single-purpose stopes to multifunctional infrastructures. Centered on four guiding principles, i.e., energy, ergonomics, water resources, and circularity, this study reviews the synergetic planning process …

Latest Advances In Research On Co2-Enhanced Coalbed Methane Recovery, Sang Shuxun, Liu Shiqi, Li Dianshang, Zhang Shouren, Xu Tianfu, Han Sijie, Zhou Xiaozhi, Huang Fansheng, Liu Tong, Tian Yuchen, Zhang Helong, Niu Qinghe, Chen Yongchun, Zhang Bing, Wu Jie

Coal Geology & Exploration

Background The CO₂-enhanced coalbed methane recovery (CO₂-ECBM) technology integrates greenhouse gas emission reduction and enhanced CBM recovery, holding great significance for achieving the goals of peak carbon dioxide emissions and carbon neutrality of China and ensuring national energy security. However, due to limitations of insufficient fundamental research and some technical bottlenecks, the engineering application of the CO₂-ECBM technology remains in the engineering test stage. This study reviews the latest advances in research on the mechanisms, evaluation methods, and technical systems of CO₂-ECBM and explores key scientific issues and technical pathways for geological …

Key Issues And Research Prospects Of The Commingled-Production Compatibility Of Deep Superimposed Coalbed Methane Systems, Guo Chen, Wang Shuangming, Qin Yong, Xu Fengyin, Sun Xueyang, Xia Yucheng, Hou Enke, Wang Sujian, Sun Qiang, Wang Shengquan, Tang Shengli, Yang Xiankuo, Gao Junzhe, Li Ruiteng, Shi Kang

Coal Geology & Exploration

Objective In recent years, significant breakthroughs have been achieved in the exploration and exploitation of deep coalbed methane (CBM), which has emerged as a major area for the reserve growth and production addition of CBM in China. Variations in the temperature and pressure conditions of deep formations inevitably cause substantial differences in the commingled-production compatibility of deep and shallow superimposed CBM systems. Therefore, revealing the depth effects of the commingled-production compatibility is critical to enhancing the efficiency of the multi-layer commingled production of deep CBM and even coal-measure gas. Methods Using a systematic literature survey of the exploration and exploitation …

Ecological Restoration Strategies Based On Plant And Soil Characteristics For Dumps Of Surface Coal Mines In Cold Arid Regions, Wang Hao, Li Haichao, Jiang Xinjun, Cao Shumiao, Yang Fan, Wang Qiangmin, Xu Ganggang, Shi Hui

Coal Geology & Exploration

Objective The dumps of surface coal mines in cold arid regions represent ecologically vulnerable areas formed under extreme disturbance. However, a lack of systematic studies on the vegetation and soils in dumps, including their spatial variation patterns and synergistic mechanisms caused by vertical differences of the dumps, leads to insufficient theoretical bases for formulating differential ecological restoration strategies in engineering practice.Methods By integrating field ecological surveys and physicochemical tests in the laboratory, this study investigated the dump with elevations ranging from 2498 m-2632 m of the Heishan coal mine on the northern slope of the Tianshan Mountains, Xinjiang. Based …

Advances In Research On Eco-Geological Environment Monitoring Of Underground Coal Mining Areas Based On Airborne Remote Sensing, Li Jun, Zou Zhaohui, Zhang Chengye, Wang Yi, Cheng Yang, Xu Lianhang, Zhang Jinhe, Liu Chuanrui, Liang Lixia

Coal Geology & Exploration

Background Timely and effective monitoring of the current status of eco-geological environment holds great significance for scientific decision-making regarding both geological environment protection and ecological restoration in underground coal mining areas. Owing to its advantage of large-scale and rapid monitoring, airborne remote sensing technology has emerged as an important approach to the eco-geological environment monitoring of mining areas. Advances This study first clarifies relevant concepts of eco-geological environment monitoring, as well as the monitoring requirements and contents specific to underground coal mining areas. Accordingly, it presents a summary of the advances in research on airborne remote sensing technology for the …

From Follower To Leader: Seismic Coal Exploration Techniques In China Over The Past 70 Years−In Celebration Of The 70th Anniversary Of Ccteg Xi’An Research Institute (Group) Co., Ltd., Cheng Jianyuan, Wang Yunhong, Wang Baoli, Li Gang, Li Yuteng, Qin Si

Coal Geology & Exploration

Background After 70 years of innovation and development, China has successfully transformed from a follower into a leader in both high-resolution surface seismic coal exploration techniques and underground in-seam seismic exploration techniques for coal mines. Furthermore, it has achieved disruptive innovations in intelligent seismic-while-mining (SWM) and seismic-while-tunneling (SWT) techniques. These achievements have established China’s worldwide leading position in the overall development of seismic coal exploration techniques.Advances In terms of high-resolution surface seismic coal exploration techniques, China has undergone four development stages: arduously catching up, striving to follow, keeping pace with continuously, and overtaking international counterparts with advanced techniques during …

Entropy-Constrained Closure For Steady, Quasi-One-Dimensional Flow Of Ideal Gases, Andrew A. Oliva

Michigan Tech Publications

An entropy-constrained closure is developed for steady quasi-one-dimensional flow of a calorically perfect ideal gas. Net irreversibility is represented by a prescribed entropy change between the inlet and outlet or, equivalently, by a stagnation pressure ratio together with the stagnation temperature ratio implied by the energy balance equation. The thermodynamic constraint, enforced through Gibbs relation together with conservation of mass and energy, yields an algebraic mapping from the inlet flow state, area ratio and prescribed stagnation property ratios to the outlet flow state. The momentum balance is retained only as an auxiliary post-processing relation and may be used to infer …

Sealing Performance Evaluation Criteria And Profile Optimization Of The Volumetric Cavities Of Positive Displacement Motors For Directional Drilling, Kuang Yuchun, Hu Xin, Zhou Jingpei, Luo Jinwu, Liu Yihui, Han Yiwei

Coal Geology & Exploration

Objective Constrained by complex stratigraphic conditions in underground coal mines, directional drilling faces challenges such as low efficiency when encountering medium-hard and hard formations. Positive displacement motors (PDMs) with a diameter of 89 mm are commonly used for directional drilling. Their efficiency is primarily influenced by the sealing performance of their volumetric cavities, which further significantly affects the drilling efficiency. Methods Based on the structural characteristics of the three-dimensional (3D) volumetric cavities of PDMs and the simulation method of two-way fluid-structure interactions, this study proposed the criteria for quantitatively evaluating the efficiency and volumetric cavity performance of PDMs, followed by …

Table Of Contents, The Editors

Coal Geology & Exploration

No abstract provided.