Article
Materials Science, Multidisciplinary
Xuebin Gu, Xufei Gong, C. G. Zhang, Yingshi Gu, Chao Wang, Guangmin Wang, Weiyao Guo
Summary: Energy accumulation and release in rock deformation and damage are crucial, and understanding the mechanism of borehole pressure relief requires investigation of damage mode and energy evolution in coal specimens with holes. Uniaxial compression AE tests were conducted on four types of drilled coal specimens to examine the effect of hole number on energy and acoustic emission (AE) evolution characteristics of brittle coal. The results showed that peak strengths and elastic moduli exhibited decreasing and linear decreasing trends, respectively, with increasing hole number. The failure mode changed from shear splitting to penetration crack damage and hole collapse with increasing hole number. Total and elastic energy decreased, while the ratios of elastic and dissipative energy to total energy exhibited opposite trends. AE activity increased with increasing hole number. Fractal characteristics of AE signals in drilled coal specimens were calculated using the G-P algorithm, and sudden drop in fractal dimension was considered a precursor of specimen failure. These findings provide insights into energy evolution mechanism and advance warning for coal pressure relief.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2023)
Article
Energy & Fuels
Mingzhong Gao, Jing Xie, Jun Guo, Yiqiang Lu, Zhiqiang He, Cong Li
Summary: The evolution of crack network in coal-rock masses can be divided into three stages, and crack connectivity increases with depth. The mining influence zones expand as depth increases, and crack connectivity is higher in deeper mines, leading to potential risks in production safety.
GEOMECHANICS AND GEOPHYSICS FOR GEO-ENERGY AND GEO-RESOURCES
(2021)
Article
Energy & Fuels
Zhibin Hao, Yujun Zuo, Hao Liu, Zehua Zhu, Jianyun Lin, Wenjibin Sun, Chao Pan, Lulin Zheng
Summary: This study reveals the damage evolution of jointed sandstone under different loading conditions using numerical models and experimental tests. A fractal dimension algorithm based on acoustic emission (AE) fields is proposed to assess the damage evolution. The findings are important for understanding the rules of jointed sandstone breakage and energy consumption, as well as searching for efficient and energy-saving rock-breaking technologies.
GEOMECHANICS AND GEOPHYSICS FOR GEO-ENERGY AND GEO-RESOURCES
(2022)
Article
Energy & Fuels
Yi Xue, P. G. Ranjith, Yang Chen, Chengzheng Cai, Feng Gao, Xingguang Liu
Summary: Geological sequestration of CO2 is important for reducing global warming and achieving carbon neutralization. This study evaluates the effect of CO2 adsorption pressure on the mechanical properties of coal mass using experimental and analytical methods. An elastic damage model is established to describe the nonlinear stress-strain relationship of coal under CO2 adsorption. The results show that increasing adsorption pressure increases the risk of coal damage and fracturing, leading to a more complex fracturing process.
Article
Mechanics
Zesheng Zang, Zhonghui Li, Yue Niu, Shan Yin
Summary: This study conducted experiments and recorded signals to investigate the fracture behavior and damage evolution characteristics of coal samples. The results showed that as loading proceeds, the stress, electric potential (EP), and acoustic emission (AE) values increase, and EP and AE signals are excited when stress drops. The fracture behavior of coal samples is altered by flaw inclination, and the destruction mode becomes increasingly complicated. The damage evolution characteristics of coal samples can be evaluated and analyzed by defining the coefficient of variation (CV value) of EP and the b value of AE.
ENGINEERING FRACTURE MECHANICS
(2024)
Article
Energy & Fuels
Yu Zhao, Chaolin Wang, Lin Ning, Houfa Zhao, Jing Bi
Summary: This paper conducted triaxial compression tests on coal samples using a nuclear magnetic resonance (NMR) testing system, investigated the development of pores and fractures in coal under stress conditions, proposed a new method for estimating crack-initiation stresses, and analyzed the fractal dimensions of pores.
Article
Mining & Mineral Processing
Jinjing Zuo, Renshu Yang, Min Gong, Xinmin Ma, Yanbing Wang
Summary: This study conducted a blasting experiment on iron ore samples and analyzed the resulting fracture characteristics. The decoupling coefficient was found to significantly affect the fracture modes and degree of damage.
INTERNATIONAL JOURNAL OF MINING SCIENCE AND TECHNOLOGY
(2022)
Article
Mathematics, Interdisciplinary Applications
Zhen Zhang, Gaofeng Liu, Ping Chang, Xiaoming Wang, Jia Lin
Summary: This paper proposes a novel method to calculate the fractal dimension Df for coal chemical structure and provides detailed deductions and summaries on the principle and methodology. The method was applied to calculate the fractal dimension Df for coal chemical structure from lignite to anthracite. The research results reveal that the fractal dimension Df for coal chemical structure decreases first and then increases with coalification, with the turning point corresponding to the second coalification jump (maximum vitrinite reflectance Ro, max = 1.30%). This study achieves micro characterization of coal chemical structure at the molecular scale, offering potential application value in the functional properties analysis and molecular synthesis design of coal-based material research fields.
CHAOS SOLITONS & FRACTALS
(2023)
Article
Engineering, Chemical
Wendi Wang, Zhen Liu, Mingrui Zhang, He Yang
Summary: In this paper, nitrogen adsorption measurement and low-field nuclear magnetic resonance methods are used to test the structural parameters of adsorption pores of different coal samples. It is found that the complexity of the pore size distribution increases with the increase in metamorphic degree. There is a positive correlation between the fractal dimension and the maximum adsorption capacity of N-2.
Article
Multidisciplinary Sciences
Daniel Peptenatu, Ion Andronache, Helmut Ahammer, Richard Taylor, Ioannis Liritzis, Marko Radulovic, Bogdan Ciobanu, Marin Burcea, Matjaz Perc, Tuan D. Pham, Bojan M. Tomic, Cosmin Iulian Cirstea, Adrian Nicolae Lemeni, Andreea Karina Gruia, Alexandra Grecu, Marian Marin, Herbert Franz Jelinek
Summary: This study investigates the complexity of 1200 Byzantine icons painted in Greece, Russia, and Romania between the 13th and 16th centuries using the Kolmogorov algorithmic information theory. The findings suggest that the normalized Kolmogorov compression complexity (KC) is the best approach for differentiating the icons from different schools.
SCIENTIFIC REPORTS
(2022)
Article
Energy & Fuels
Jiexin Lu, Chunshan Zheng, Wuche Liu, He Li, Shiliang Shi, Yi Lu, Qing Ye, Yuannan Zheng
Summary: Microwave-assisted acidification is a promising method for enhancing CBM recovery by improving pore structure and fracture connectivity in coal. It greatly increases pore volume, length, and width of fractures compared to microwave heating or acidification alone. This study demonstrates the significant potential of microwave-assisted acidification for CBM production.
Article
Geosciences, Multidisciplinary
Cong Feng, Xijian Li, Enyu Xu, Hao Sui, Feng Xue, Honggao Xie
Summary: This study demonstrates the significant influence of coal pore structure on coalbed methane exploitation. The pore structure of tectonic coal is shown to be more complex compared to primary structural coal, with increased connected pores and enhanced adsorption capacity.
NATURAL RESOURCES RESEARCH
(2023)
Article
Engineering, Geological
Anlin Zhang, Heping Xie, Ru Zhang, Mingzhong Gao, Jing Xie, Zheqiang Jia, Li Ren, Zetian Zhang
Summary: This research comprehensively analyzed the mechanical behavior of coal at different depths during mining through experiments. The results showed that with increasing depth, the strength and deformation of coal increased, the evolution of the Poisson's ratio presented a nonlinear increase, and the elastic modulus gradually decreased. The plastic deformation and progressive damage characteristics of the coal became more significant. The analysis of acoustic emission monitoring revealed that shallow coal samples failed mainly due to tensile cracking, while deep coal samples failed due to shear cracking. The energy evolution and partition characteristics were also investigated, showing an increase in the storage capacity of elastic strain energy with depth. The study also found that the damage development process of deeper coal was slower, but the damage degree was more serious. An improved damage model considering the depth effect was established. The model prediction curves agreed well with the testing values.
INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES
(2023)
Article
Mathematics
Alexey Gvozdarev, Roman Parovik
Summary: The fractal dimension of geomagnetic field variations at Baigazan magnetic station in Russian Altay during 2011-2013 were calculated using the Higuchi method. The daily variation of Higuchi Fractal Dimension (HFD) for the D, H, Z components of the geomagnetic field were studied, and their contribution to HFD variability was found to be 30-40% of total variance. A correlation analysis was conducted between the fractal dimension of D, H, Z variations and the Auroral Electrojet (AE) index and solar wind characteristics, revealing negative correlations with the AE-index, IMF strength, and solar wind velocity.
Article
Engineering, Chemical
Chuangkai Zheng, Qiangling Yao, Xuehua Li, Karen Hudson-Edwards, Changhao Shan, Xiaobei Shang, Yong Li
Summary: This study investigates the drying and mechanical properties of long flame coal and anthracite after exposure to different drying temperatures. The results show that the degree of drying increases with higher drying temperatures and leads to decreased strength and increased brittleness and damage in anthracite samples.
Article
Thermodynamics
Cong Li, Heping Xie, Mingzhong Gao, Ling Chen, Le Zhao, Cunbao Li, Nianhan Wu, Zhiqiang He, Jianan Li
Summary: This study focuses on the optimization of pressure controller design to enhance the upper pressure limit for obtaining natural gas hydrates in-situ. By proposing innovative pressure controllers and conducting numerical simulations and experimental tests, effective methods for improving pressure controller strength are provided. The novel saddle-type pressure controller demonstrates the best design and substantially increases the pressure controller bearing capacity.
Article
Thermodynamics
Zhihe Wang, Jun Wang, Changtai Zhou, Cunbao Li, Heping Xie
Summary: The primary wall roughness has dominating effects on overall flow behavior, while the secondary roughness only adds additional flow resistance. Neglecting secondary roughness in analyzing larger-scale problems may lead to potential deviations.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Article
Engineering, Geological
Jun Wang, Heping Xie, Cunbao Li
Summary: The laboratory hydraulic fracturing tests on Longmaxi shale samples from southwest China revealed significant brittle failure characteristics and anisotropic phenomena, with main failure patterns identified as split, split-bending, and slip along the bedding plane. Anomalously high breakdown pressure was observed in the samples at different layer orientations, which led to the development of a new tensile stress-based model for interpreting such unusual pressures. This study may have practical implications for field hydraulic fracturing operations.
INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES
(2021)
Article
Geosciences, Multidisciplinary
Long Xiting, Liu Fei, Xie Heping, Lin Wenjing, Liu Yanguang, Li Cunbao
Summary: In this study, a CPU/GPU collaborative parallel prestack time migration methodology was proposed for geothermal resource exploration. The method involved analyzing geological conditions, designing seismic test sections, and using the multiple coverage reflection wave exploration method to obtain seismic data. The obtained data were then analyzed using CPU/GPU collaborative parallel prestack time migration technology for geothermal resource evaluation.
ACTA GEOLOGICA SINICA-ENGLISH EDITION
(2022)
Article
Mechanics
Cunbao Li, Dongchao Yang, Heping Xie, Li Ren, Jun Wang
Summary: Studying the anisotropic fracture behavior of shale is crucial for evaluating the development of a stimulated reservoir volume. The fracture toughness decreases with increasing bedding dip angle, reaching maximum and minimum values at 0 degrees and 90 degrees, respectively, with a ratio of 1.60. The crack propagates along the bedding plane when the dip angle is higher than 45 degrees.
ENGINEERING FRACTURE MECHANICS
(2021)
Article
Engineering, Geological
H. J. Lu, H. P. Xie, Y. Luo, L. Ren, R. Zhang, C. B. Li, J. Wang, M. Q. Yang
Summary: The study conducted direct shear tests on shale samples with different bedding orientations and found significant anisotropies in the shear stress-displacement relation, failure patterns, and shear strength. The new anisotropic shear failure criterion proposed in the study showed good agreement with the test results, indicating that the maximum shear strength in shale varies with the applied normal stress.
INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES
(2021)
Article
Engineering, Civil
Zhihe Wang, Changtai Zhou, Fei Wang, Cunbao Li, Heping Xie
Summary: This study investigates flow channeling and anomalous transport behaviors in a granite fracture, focusing on the impact of increasing surface contacts. The results show that areas with large apertures but poor connectivity in the fracture may have negligible contribution to overall flow, with limited effect on solute transport. Increased surface contact leads to stronger flow channeling and anomalous transport due to enhanced flow heterogeneity from the complex fracture void structure.
JOURNAL OF HYDROLOGY
(2021)
Article
Engineering, Geological
Changtai Zhou, Heping Xie, Jianbo Zhu, Zhihe Wang, Cunbao Li, Fei Wang
Summary: The study reveals that the proportion and grain size of infilling significantly impact the cracking processes and failure modes of brittle materials. Uniaxial compression tests show that the compressive strength and deformation modulus increase with higher cement proportion or larger grain sizes due to stress redistribution around inclusions. Debonding behavior becomes significant with a higher cement proportion or larger grain sizes, while the number of AE events is negatively correlated to the infilling composition.
ROCK MECHANICS AND ROCK ENGINEERING
(2022)
Article
Geochemistry & Geophysics
Liang-Juan Zheng, He-Ping Xie, Zheng-Xuan Xu, Jian-Hui Deng, Dong Wang, Guang-Ze Zhang, Cun-Bao Li, Ru Zhang, Gan Feng
Summary: Water content significantly affects the physical and mechanical properties of rock, leading to rock instability and geologic disasters. Saturated slates have different mechanical properties and failure processes compared to unsaturated slates. AE monitoring shows that the deformation and fracturing of unsaturated slates occur intensely, while in saturated slates, they occur with low energy and uniform distribution. Water content also decreases the brittleness index of unsaturated slates.
Article
Engineering, Geological
Jun Lu, Heping Xie, Minghui Li, Cunbao Li, Mingzhong Gao, Delei Shang, Jianhua Li
Summary: This study investigates the mechanical behavior of sandstone under different microwave irradiation conditions through true triaxial tests. The results demonstrate that the strength of irradiated sandstone first increases and then decreases. The peak brittleness of the sandstone increases with an increase in stress. The stress difference induced by water vapor expansion and mineral thermal expansion is the main factor for microwave breaking water-bearing sandstone.
INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES
(2022)
Article
Energy & Fuels
Mingzhong Gao, Xuan Wang, Guoqing Zhang, Minghui Li, Tao Liu, Haichun Hao, Cunbao Li, Heping Xie
Summary: This article introduces the history and current status of lunar sampling, as well as the importance and scientific concept of in-situ condition preserved coring. It also proposes the principles and critical technologies of the four Ps coring, and introduces the latest research progress.
GEOMECHANICS AND GEOPHYSICS FOR GEO-ENERGY AND GEO-RESOURCES
(2022)
Article
Energy & Fuels
Shuo Zhai, Heping Xie, Peng Cui, Daqin Guan, Jian Wang, Siyuan Zhao, Bin Chen, Yufei Song, Zongping Shao, Meng Ni
Summary: The authors introduce a machine learning-driven approach to accelerate the discovery of efficient oxygen reduction electrodes for ceramic fuel cells by utilizing ionic Lewis acid strength as an effective physical descriptor. Experimental validation confirms the superior activity metrics of four oxides out of 6,871 distinct perovskite compositions, highlighting the importance of ISA in improving oxygen reduction reaction activity in perovskite oxides.
Article
Multidisciplinary Sciences
Heping Xie, Zhiyu Zhao, Tao Liu, Yifan Wu, Cheng Lan, Wenchuan Jiang, Liangyu Zhu, Yunpeng Wang, Dongsheng Yang, Zongping Shao
Summary: This article introduces a method for direct seawater electrolysis for hydrogen production, which can solve the problems of side reactions and corrosion. In the experiment, this method stably operated for over 3200 hours under practical application conditions. The method is efficient, size-flexible, scalable, and has high practical value without increasing the operation cost.
Article
Engineering, Geological
Yifei Liu, Dong-Sheng Jeng, Heping Xie, Cunbao Li
Summary: Particle morphology is a fundamental property of granular geomaterials. This study introduces the Hilbert-Huang transform into morphology analysis and establishes a comprehensive descriptor system based on geometric measure theory. The characterization and corresponding program have the potential to be applied to any irregular geometry.
Article
Thermodynamics
Heping Xie, Tianyi Gao, Xiting Long, Licheng Sun, Jun Wang, Entong Xia, Shuheng Li, Biao Li, Cunbao Li, Mingzhong Gao, Zhengyu Mo
Summary: This study designed and tested a modular 1 kilowatt-level thermoelectric generator (TEG) system, and the experimental results validated the feasibility of modular technology and highlighted its potential for medium-low temperature geothermal energy application.
ENERGY CONVERSION AND MANAGEMENT
(2023)