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Haile N, Sajjad M, Zhang Y, AlAmoodi N, AlMarzooqi F, Zhang T. Pore-scale physics of ice melting within unconsolidated porous media revealed by non-destructive magnetic resonance characterization. Sci Rep 2024; 14:5635. [PMID: 38453999 PMCID: PMC10920668 DOI: 10.1038/s41598-024-56294-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Accepted: 03/05/2024] [Indexed: 03/09/2024] Open
Abstract
Melting of ice in porous media widely exists in energy and environment applications as well as extraterrestrial water resource utilization. In order to characterize the ice-water phase transition within complicated opaque porous media, we employ the nuclear magnetic resonance (NMR) and imaging (MRI) approaches. Transient distributions of transverse relaxation time T2 from NMR enable us to reveal the substantial role of inherent throat and pore confinements in ice melting among porous media. More importantly, the increase in minimum T2 provides new findings on how the confinement between ice crystal and particle surface evolves inside the pore. For porous media with negligible gravity effect, both the changes in NMR-determined melting rate and our theoretical analysis of melting front confirm that conduction is the dominant heat transfer mode. The evolution of mushy melting front and 3D spatial distribution of water content are directly visualized by a stack of temporal cross-section images from MRI, in consistency with the corresponding NMR results. For heterogeneous porous media like lunar regolith simulant, the T2 distribution shows two distinct pore size distributions with different pore-scale melting dynamics, and its maximum T2 keeps increasing till the end of melting process instead of reaching steady in homogeneous porous media.
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Affiliation(s)
- Natnael Haile
- Department of Mechanical and Nuclear Engineering, Khalifa University of Science and Technology, P.O. Box 127788, Abu Dhabi, United Arab Emirates
| | - Muhammad Sajjad
- Department of Mechanical and Nuclear Engineering, Khalifa University of Science and Technology, P.O. Box 127788, Abu Dhabi, United Arab Emirates
| | - Yadong Zhang
- Department of Mechanical and Nuclear Engineering, Khalifa University of Science and Technology, P.O. Box 127788, Abu Dhabi, United Arab Emirates
| | - Nahla AlAmoodi
- Department of Chemical and Petroleum Engineering, Khalifa University of Science and Technology, P.O. Box 127788, Abu Dhabi, United Arab Emirates
| | - Faisal AlMarzooqi
- Department of Chemical and Petroleum Engineering, Khalifa University of Science and Technology, P.O. Box 127788, Abu Dhabi, United Arab Emirates
| | - TieJun Zhang
- Department of Mechanical and Nuclear Engineering, Khalifa University of Science and Technology, P.O. Box 127788, Abu Dhabi, United Arab Emirates.
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Nartowska E, Kanuchova M, Kozáková Ľ. Assessment of Unfrozen Water Content in Copper Bentonites Using the 1H NMR Technique: Optimization, the Method's Limitation, and Comparative Analysis with DSC. MATERIALS (BASEL, SWITZERLAND) 2023; 16:7577. [PMID: 38138722 PMCID: PMC10744833 DOI: 10.3390/ma16247577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 11/23/2023] [Accepted: 12/07/2023] [Indexed: 12/24/2023]
Abstract
Studies on changes in unfrozen water content in copper bentonite from Slovakia were conducted using both differential scanning calorimetry (DSC) and nuclear magnetic resonance (NMR) methods. The aims of this study were to 1. optimize the method for determining changes in unfrozen water content using the 1H NMR technique in model bentonites based on the DSC results; 2. analyze the relationship between unfrozen water content, as determined via DSC and the optimized NMR technique, and the physicochemical parameters of bentonites; and 3. identify the limitations in determining changes in unfrozen water content using the 1H NMR technique in relation to copper-contaminated bentonites. The results obtained using the optimized NMR method applied to the model bentonites correlated well with the DSC results. The unfrozen water content in the Cu-contaminated bentonites was 2-18% lower after NMR compared to the DSC results, likely due to the mobility of copper ions and their paramagnetic properties. Statistically significant differences in unfrozen water content between the DSC and NMR methods were observed, depending on molar concentration, copper ion concentration, and temperature, confirmed via Analysis of Variance (ANOVA). Calorimetric studies are recommended for investigating unfrozen water content changes in contaminated clays. Further NMR research could identify metals influencing free induction decay signals under varying physicochemical conditions.
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Affiliation(s)
- Edyta Nartowska
- Faculty of Environmental Engineering, Geomatics and Renewable Energy, Kielce University of Technology, al. 1000-lecia PP 7, 25-314 Kielce, Poland
| | - Maria Kanuchova
- Faculty of Mining, Ecology, Process Control and Geotechnologies, Technical University of Kosice, Letna 9, 042 00 Kosice, Slovakia; (M.K.); (Ľ.K.)
| | - Ľubica Kozáková
- Faculty of Mining, Ecology, Process Control and Geotechnologies, Technical University of Kosice, Letna 9, 042 00 Kosice, Slovakia; (M.K.); (Ľ.K.)
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Ali M, Wang E, Li Z, Khan NM, Sabri Sabri MM, Ullah B. Investigation of the acoustic emission and fractal characteristics of coal with varying water contents during uniaxial compression failure. Sci Rep 2023; 13:2238. [PMID: 36755100 PMCID: PMC9908880 DOI: 10.1038/s41598-023-29473-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Accepted: 02/06/2023] [Indexed: 02/10/2023] Open
Abstract
To investigate the effect of water on the mechanical properties and acoustic emission (AE) characteristics of coal in the failure and deformation processes. Coal samples of different content were subjected to uniaxial compression tests and AE signals were monitored. The characteristics of the AE signals were further analyzed using fractal analysis. The results show that saturated coal samples have substantially reduced mechanical properties such as uniaxial compressive strength (UCS), dissipation energy, peak stress, and elastic modulus. Under loading, stress-strain curves are characterized by five distinct stages: (1) compaction; (2) linear elastic; (3) crack stable propagation; (4) crack accelerating propagation; and (5) post-peak and residual stages. Using phase-space theory, a novel Grassberger Procaccia (GP) algorithm was utilized to find the AE fractal characteristics of coal samples in different stages. It is significant to note that AE energy does not exhibit fractal characteristics in either the first or second stages. Contrary to the first two stages, the third stage showed obvious fractal characteristics. Fractal analysis of AE time sequences indicates that fractal dimension values change as stress increases, indicating the initiation of complex microcracks in coal. In the fourth stage, the fractal dimension rapidly declines as the strength reaches its limit, indicating the occurrence of macrocracks. However, fractal dimensions continued to decrease further or increased slightly in the fifth stage. Consequently, the coal begins to collapse, potentially resulting in a disaster and failure. It is, therefore, possible to accurately predict coal and rock dynamic failures and microcrack mechanisms by observing the subsequent sudden drop in the correlation dimension of the AE signals in response to different stages of loading.
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Affiliation(s)
- Muhammad Ali
- grid.411510.00000 0000 9030 231XSchool of Safety Engineering, China University of Mining and Technology, Xuzhou, 221116 China ,grid.440526.10000 0004 0609 3164Department of Mining Engineering, Engineering and Management Sciences, Balochistan University of Information Technology, Quetta, Pakistan ,grid.411510.00000 0000 9030 231XKey Laboratory of Gas and Fire Control for Coal Mines of Ministry of Education, China University of Mining and Technology, Xuzhou, 221116 China
| | - Enyuan Wang
- School of Safety Engineering, China University of Mining and Technology, Xuzhou, 221116, China. .,Key Laboratory of Gas and Fire Control for Coal Mines of Ministry of Education, China University of Mining and Technology, Xuzhou, 221116, China.
| | - Zhonghui Li
- School of Safety Engineering, China University of Mining and Technology, Xuzhou, 221116, China. .,Key Laboratory of Gas and Fire Control for Coal Mines of Ministry of Education, China University of Mining and Technology, Xuzhou, 221116, China.
| | - Naseer Muhammad Khan
- grid.412117.00000 0001 2234 2376Department of Sustainable Advanced Geomechanical Engineering, Military College of Engineering, National University of Sciences and Technology, Risalpur, 23200 Pakistan
| | - Mohanad Muayad Sabri Sabri
- grid.32495.390000 0000 9795 6893Peter the Great St. Petersburg Polytechnic University, St. Petersburg, 195220 Russia
| | - Barkat Ullah
- grid.411510.00000 0000 9030 231XSchool of Safety Engineering, China University of Mining and Technology, Xuzhou, 221116 China ,grid.216417.70000 0001 0379 7164School of Resources and Safety Engineering, Central South University, Changsha, 410083 China
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Li B, Shi Z, Wang Z, Huang L. Effect of Liquid Nitrogen Freeze-Thaw Cycles on Pore Structure Development and Mechanical Properties of Coal. ACS OMEGA 2022; 7:5206-5216. [PMID: 35187336 PMCID: PMC8851649 DOI: 10.1021/acsomega.1c06296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 01/21/2022] [Indexed: 06/14/2023]
Abstract
To improve the mining efficiency of coalbed methane, liquid nitrogen freeze-thawing experiments were performed to improve coal seam permeability and to study its influence on coal pore structure development and mechanical properties. Mechanical properties and nuclear magnetic resonance tests of coal samples were performed with 0, 5, 10, and 15 freeze-thaw cycles of liquid nitrogen. The results show that the number of freeze-thaw cycles caused the change of uniaxial compressive strength and elastic modulus of coal, and the change effect decreased significantly after 11-15 freeze-thaw cycles. Between 0 and 5 freeze-thaw cycles, the base growth rate of the transverse relaxation time T 2 spectral area of the full pore of coal is 44.1%, and that of the transverse relaxation time T 2 spectral area of adsorption pore is 71.5%. After 6-10 freeze-thaw cycles, the fixed base growth rate of the transverse relaxation time T 2 spectral area of the full hole of coal is 269.0%, and the chain growth rate is 156.2%. In this stage, the chain growth rate of the transverse relaxation time T 2 spectral area of the seepage hole is 198.4%, which is mainly the growth of seepage hole volume. After 11-15 freeze-thaw cycles, the chain growth rate of the full pore of coal transverse relaxation time T 2 spectrum area is 20.1%, the chain growth rate of adsorption pore is 4.8%, the chain growth rate of seepage pore is 22.2%, and the growth rate of the pore volume is greatly reduced. Comparing the changes of pore and coal mechanical properties in different pore sizes, it can be seen that the change of adsorption pore volume has a greater impact on coal mechanical properties.
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Affiliation(s)
- Bo Li
- School
of Safety Science and Engineering, Henan
Polytechnic University, Jiaozuo 454003, China
- Collaborative
Innovation Center of Coal Work Safety and Clean High Efficiency Utilization, Henan Polytechnic University, Jiaozuo 454003, China
- State
Key Laboratory Cultivation Base for Gas Geology and Gas Control, Henan Polytechnic University, Jiaozuo Henan 454003, China
| | - Zhen Shi
- School
of Safety Science and Engineering, Henan
Polytechnic University, Jiaozuo 454003, China
| | - Zeqi Wang
- School
of Safety Science and Engineering, Henan
Polytechnic University, Jiaozuo 454003, China
| | - Laisheng Huang
- School
of Safety Science and Engineering, Henan
Polytechnic University, Jiaozuo 454003, China
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Li B, Li L, Huang L, Lv X. The Temperature Field Evolution and Water Migration Law of Coal under Low-Temperature Freezing Conditions. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:13188. [PMID: 34948801 PMCID: PMC8703614 DOI: 10.3390/ijerph182413188] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 12/08/2021] [Accepted: 12/09/2021] [Indexed: 11/16/2022]
Abstract
This study examines the evolution law of the coal temperature field under low-temperature freezing conditions. The temperature inside coal samples with different water contents was measured in real-time at several measurement points in different locations inside the sample under the condition of low-temperature medium (liquid nitrogen) freezing. The temperature change curve was then used to analyse the laws of temperature propagation and the movement of the freezing front of the coal, which revealed the mechanism of internal water migration in the coal under low-temperature freezing conditions. The results indicate that the greater the water content of the coal sample, the greater the temperature propagation rate. The reasons for this are the phase change of ice and water inside the coal during the freezing process; the increase in the contact area of the ice and coal matrix caused by the volume expansion; and the joint action of the two. The process of the movement of the freezing front is due to the greater adsorption force of the ice lens than that of the coal matrix. Thus, the water molecules adsorbed in the unfrozen area of the coal matrix migrate towards the freezing front and form a new ice lens. Considering the temperature gradient and water content of the coal samples, Darcy's permeation equation and water migration equation for the inside of the coal under freezing conditions were derived, and the segregation potential and matrix potential were analysed. The obtained theoretical and experimental results were found to be consistent. The higher the water content of the coal samples, the smaller the matrix potential for the hindrance of water migration. Furthermore, the larger the temperature gradient, the larger the segregation potential, and the faster the water migration rate.
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Affiliation(s)
- Bo Li
- School of Safety Science and Engineering, Henan Polytechnic University, Jiaozuo 454003, China; (L.L.); (L.H.); (X.L.)
- Collaborative Innovation Center of Coal Work Safety and Clean High Efficiency Utilization, Henan Polytechnic University, Jiacozuo 454003, China
- State Key Laboratory Cultivation Base for Gas Geology and Gas Control, Henan Polytechnic University, Jiaozuo 454003, China
| | - Li Li
- School of Safety Science and Engineering, Henan Polytechnic University, Jiaozuo 454003, China; (L.L.); (L.H.); (X.L.)
- State Key Laboratory Cultivation Base for Gas Geology and Gas Control, Henan Polytechnic University, Jiaozuo 454003, China
| | - Laisheng Huang
- School of Safety Science and Engineering, Henan Polytechnic University, Jiaozuo 454003, China; (L.L.); (L.H.); (X.L.)
- State Key Laboratory Cultivation Base for Gas Geology and Gas Control, Henan Polytechnic University, Jiaozuo 454003, China
| | - Xiaoquan Lv
- School of Safety Science and Engineering, Henan Polytechnic University, Jiaozuo 454003, China; (L.L.); (L.H.); (X.L.)
- State Key Laboratory Cultivation Base for Gas Geology and Gas Control, Henan Polytechnic University, Jiaozuo 454003, China
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