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Dr. Zhenxue Dai
College of Construction Engineering, Jilin University, Changchun, China

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Research Keywords & Expertise

0 Flow and transport in porous media
0 Reservoir Characterization
0 Carbon storage
0 nuclear waste disposal
0 Geochemical modeling

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Flow and transport in porous media
Reservoir Characterization
Carbon storage
Geochemical modeling

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Review
Published: 30 August 2021 in Energies
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The built environment is the global sector with the greatest energy use and greenhouse gas emissions. As a result, building energy savings can make a major contribution to tackling the current energy and climate change crises. Fluid dynamics models have long supported the understanding and optimization of building energy systems and have been responsible for many important technological breakthroughs. As Covid-19 is continuing to spread around the world, fluid dynamics models are proving to be more essential than ever for exploring airborne transmission of the coronavirus indoors in order to develop energy-efficient and healthy ventilation actions against Covid-19 risks. The purpose of this paper is to review the most important and influential fluid dynamics models that have contributed to improving building energy efficiency. A detailed, yet understandable description of each model’s background, physical setup, and equations is provided. The main ingredients, theoretical interpretations, assumptions, application ranges, and robustness of the models are discussed. Models are reviewed with comprehensive, although not exhaustive, publications in the literature. The review concludes by outlining open questions and future perspectives of simulation models in building energy research.

ACS Style

Xiaoshu Lü; Tao Lu; Tong Yang; Heidi Salonen; Zhenxue Dai; Peter Droege; Hongbing Chen. Improving the Energy Efficiency of Buildings Based on Fluid Dynamics Models: A Critical Review. Energies 2021, 14, 5384 .

AMA Style

Xiaoshu Lü, Tao Lu, Tong Yang, Heidi Salonen, Zhenxue Dai, Peter Droege, Hongbing Chen. Improving the Energy Efficiency of Buildings Based on Fluid Dynamics Models: A Critical Review. Energies. 2021; 14 (17):5384.

Chicago/Turabian Style

Xiaoshu Lü; Tao Lu; Tong Yang; Heidi Salonen; Zhenxue Dai; Peter Droege; Hongbing Chen. 2021. "Improving the Energy Efficiency of Buildings Based on Fluid Dynamics Models: A Critical Review." Energies 14, no. 17: 5384.

Research article
Published: 02 June 2021 in Advances in Materials Science and Engineering
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Grouting is a common and important technique for water bursting prevention in coal mines; the success of grouting in coal mines depends highly on the flowability of grouting materials and the strength of the hardened body as well. In this paper, a series of performance tests, in terms of the water-cement ratio, viscosity, drainage rate, presetting time, final setting time, compressive strength, and permeability were conducted on the cement-fly ash-based grout at various mixture ratios. The evolution of these performances versus different mixture ratios was analyzed; targeting at the reasonable flowability and hardened strength of grouting materials, an optimized mixture ratio was recognized for water bursting prevention in coal mines. Furthermore, the diffusion experiments of optimized grout material were designed taking into account the influence of confining and hydraulic pressure in the porous medium. As a result, the confining and hydraulic pressures have a linear negative correlation with the diffusion distance of grout materials. These results have guiding significance to water bursting prevention in coal mines.

ACS Style

Huiqing Lian; Haiyang Yi; Zhenxue Dai; Junwen Yang; Zhenxing Ji; Ruigang Han; Lu Meng; Yi Yang. Experimental Investigation on the Mixture Ratio and Diffusion Performance of Grouting Materials for Water Bursting Prevention in Coal Mines. Advances in Materials Science and Engineering 2021, 2021, 1 -11.

AMA Style

Huiqing Lian, Haiyang Yi, Zhenxue Dai, Junwen Yang, Zhenxing Ji, Ruigang Han, Lu Meng, Yi Yang. Experimental Investigation on the Mixture Ratio and Diffusion Performance of Grouting Materials for Water Bursting Prevention in Coal Mines. Advances in Materials Science and Engineering. 2021; 2021 ():1-11.

Chicago/Turabian Style

Huiqing Lian; Haiyang Yi; Zhenxue Dai; Junwen Yang; Zhenxing Ji; Ruigang Han; Lu Meng; Yi Yang. 2021. "Experimental Investigation on the Mixture Ratio and Diffusion Performance of Grouting Materials for Water Bursting Prevention in Coal Mines." Advances in Materials Science and Engineering 2021, no. : 1-11.

Journal article
Published: 28 May 2021 in Sustainability
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This paper examines the remediation techniques of cadmium (Cd)-contaminated dredged river sediments after land disposal in a city in East China. Three remediation techniques, including stabilization, soil leaching, and phytoremediation, are compared by analyzing the performance of the techniques for Cd-contaminated soil remediation. The experimental results showed that the stabilization technique reduced the leaching rate of soil Cd from 33.3% to 14.3%, thus effectively reducing the biological toxicity of environmental Cd, but the total amount of Cd in soil did not decrease. Leaching soil with citric acid and oxalic acid achieved Cd removal rates of 90.1% and 92.4%, respectively. Compared with these two remediation techniques, phytoremediation was more efficient and easier to implement and had less secondary pollution, but it took more time, usually several years. In this study, these three remediation techniques were analyzed and discussed from technical, economic, and environmental safety perspectives by comprehensively considering the current status and future plans of the study site. Soil leaching was found to be the best technique for timely treatment of Cd contamination in dredged river sediments after land disposal.

ACS Style

Changsong Zhang; Xueke Zang; Zhenxue Dai; Xiaoying Zhang; Ziqi Ma. Remediation Techniques for Cadmium-Contaminated Dredged River Sediments after Land Disposal. Sustainability 2021, 13, 6093 .

AMA Style

Changsong Zhang, Xueke Zang, Zhenxue Dai, Xiaoying Zhang, Ziqi Ma. Remediation Techniques for Cadmium-Contaminated Dredged River Sediments after Land Disposal. Sustainability. 2021; 13 (11):6093.

Chicago/Turabian Style

Changsong Zhang; Xueke Zang; Zhenxue Dai; Xiaoying Zhang; Ziqi Ma. 2021. "Remediation Techniques for Cadmium-Contaminated Dredged River Sediments after Land Disposal." Sustainability 13, no. 11: 6093.

Journal article
Published: 03 May 2021 in Water Resources Research
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Leakage from geologic CO2 sequestration (GCS) reservoirs to overlying underground sources of drinking water (USDW) is a tangible risk. This study is an integrated assessment that combines column experiments and reactive transport simulations of sediments sampled from the Ogallala aquifer above an active commercial‐scale GCS site (the Farnsworth Unit in northern Texas). Experimental and simulation results suggest that carbonate mineral (calcite and dolomite) dissolution is the most significant reaction following CO2 intrusion, and is also the dominant source of trace metal release. Cation exchange is another key mechanism controlling trace metal release by cation interference. Most of the trace metals, including Ba, Sr, As, Pb, and Zn, show a short‐term release and quickly drop to the baseline values, suggesting low risk to the overlying USDW quality. Other trace metals, such as Mn and U, exhibit a tangible increase of their concentrations in the beginning, and drop to a higher level compared to the baseline, which may become a potential concern of long‐term USDW quality change with CO2 introduction. This study provides a comprehensive example of combining laboratory experiments and simulations for assessment of CO2‐sediment interactions with combined release mechanisms in shallow groundwater aquifers. Data presented here provides useful insights for quantitative risk assessment and effective public education regarding CO2 geological sequestration, and trace metal reactive transport studies in shallow groundwater aquifers.

ACS Style

Ting Xiao; Wei Jia; Richard Esser; Zhenxue Dai; Brian McPherson. Potential Chemical Impacts of Subsurface CO 2 : An Integrated Experimental and Numerical Assessment for a Case Study of the Ogallala Aquifer. Water Resources Research 2021, 57, 1 .

AMA Style

Ting Xiao, Wei Jia, Richard Esser, Zhenxue Dai, Brian McPherson. Potential Chemical Impacts of Subsurface CO 2 : An Integrated Experimental and Numerical Assessment for a Case Study of the Ogallala Aquifer. Water Resources Research. 2021; 57 (5):1.

Chicago/Turabian Style

Ting Xiao; Wei Jia; Richard Esser; Zhenxue Dai; Brian McPherson. 2021. "Potential Chemical Impacts of Subsurface CO 2 : An Integrated Experimental and Numerical Assessment for a Case Study of the Ogallala Aquifer." Water Resources Research 57, no. 5: 1.

Journal article
Published: 31 March 2021 in Energies
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With the increasing depth of coal mining, the quantitative evaluation of the degree of geological structure development is becoming increasingly important for the control of mine water hazards in coal mining areas. Understanding the complexity of geological structure development can improve the safety and efficiency of coal production. At present, various evaluation indicators of the geological structure development cannot fully reflect the complexity of faults and folds, and the evaluation process is usually affected by subjective human factors. In this paper, the fractal dimension from fractal theory is used as the evaluation indicator to quantitatively analyze and evaluate the complexity of fault and fold structure in the mining area. To verify the evaluation results, the mathematical geology method is applied in an analysis of the trend surface of fault and fold networks. The results indicate that the fractal dimension can be applied for the quantitative analysis and evaluation of the complexity of fault and fold networks. In addition, the outcome of this work provides new insights into how to characterize the fault and fold structures of coal mining areas in northern China, and has some important implications to ensure the coal production safety.

ACS Style

Gaizhuo Zhang; Junzhong Guo; Bin Xu; Lulu Xu; Zhenxue Dai; Shangxian Yin; Mohamad Soltanian. Quantitative Analysis and Evaluation of Coal Mine Geological Structures Based on Fractal Theory. Energies 2021, 14, 1925 .

AMA Style

Gaizhuo Zhang, Junzhong Guo, Bin Xu, Lulu Xu, Zhenxue Dai, Shangxian Yin, Mohamad Soltanian. Quantitative Analysis and Evaluation of Coal Mine Geological Structures Based on Fractal Theory. Energies. 2021; 14 (7):1925.

Chicago/Turabian Style

Gaizhuo Zhang; Junzhong Guo; Bin Xu; Lulu Xu; Zhenxue Dai; Shangxian Yin; Mohamad Soltanian. 2021. "Quantitative Analysis and Evaluation of Coal Mine Geological Structures Based on Fractal Theory." Energies 14, no. 7: 1925.

Journal article
Published: 30 March 2021 in Energies
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This paper summarizes the risk assessment and management workflow developed and applied to the Southwest Regional Partnership on Carbon Sequestration (SWP) Phase III Demonstration Project. The risk assessment and management workflow consists of six primary tasks, including management planning, identification, qualitative analysis, quantitative analysis, response planning, and monitoring. Within the workflow, the SWP assembled and iteratively updated a risk registry that identifies risks for all major activities of the project. Risk elements were ranked with respect to the potential impact to the project and the likelihood of occurrence. Both qualitative and quantitative risk analyses were performed. To graphically depict the interactions among risk elements and help building risk scenarios, process influence diagrams were used to represent the interactions. The SWP employed quantitative methods of risk analysis including Response Surface Method (RSM), Polynomial Chaos Expansion (PCE), and the National Risk Assessment Partnership (NRAP) toolset. The SWP also developed risk response planning and performed risk control and monitoring to prevent the risks from affecting the project and ensure the effectiveness of risk management. As part of risk control and monitoring, existing and new risks have been tracked and the response plan was subsequently evaluated. Findings and lessons learned from the SWP’s risk assessment and management efforts will provide valuable information for other commercial geological CO2 storage projects.

ACS Style

Si-Yong Lee; Ken Hnottavange-Telleen; Wei Jia; Ting Xiao; Hari Viswanathan; Shaoping Chu; Zhenxue Dai; Feng Pan; Brian McPherson; Robert Balch. Risk Assessment and Management Workflow—An Example of the Southwest Regional Partnership. Energies 2021, 14, 1908 .

AMA Style

Si-Yong Lee, Ken Hnottavange-Telleen, Wei Jia, Ting Xiao, Hari Viswanathan, Shaoping Chu, Zhenxue Dai, Feng Pan, Brian McPherson, Robert Balch. Risk Assessment and Management Workflow—An Example of the Southwest Regional Partnership. Energies. 2021; 14 (7):1908.

Chicago/Turabian Style

Si-Yong Lee; Ken Hnottavange-Telleen; Wei Jia; Ting Xiao; Hari Viswanathan; Shaoping Chu; Zhenxue Dai; Feng Pan; Brian McPherson; Robert Balch. 2021. "Risk Assessment and Management Workflow—An Example of the Southwest Regional Partnership." Energies 14, no. 7: 1908.

Journal article
Published: 23 March 2021 in Journal of Hydrology
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Transport of hexavalent chromium, Cr (VI), in groundwater is largely influenced by adsorption and desorption processes. Sediment types can result in substantial difference in adsorption mechanisms. The goal of this work is to explore the adsorption mechanism of Cr (VI) within sediments with different properties and to identify the controlling factors. In this paper, Cr (VI) adsorption onto six different natural unconsolidated sediments (two loamy sands, two sandy loams, one loam, and one silty loam clay) collected from a typical fluvial aquifer in Qiqihar, China, was assessed with batch and column experiments. Equilibrium adsorption capacities and kinetic rates were quantified with batch experiments. Potential controlling effects of pH, solid/solution ratio, grain size, and clay mineral content on adsorption capacities were also analyzed. Adsorption kinetics was evaluated with Elovich, pseudo first- and second-order models, and equilibrium properties were assessed with Henry, Freundlich, and Langmuir isotherms. Model adequacy was discriminated with selection criteria of Akaike information criterion (AIC), modified Akaike information criterion (AICc), Bayesian information criterion (BIC), and Hannan information criterion (HIC). Adsorption and desorption of Cr (VI) onto and from the collected sediment samples under flow conditions were investigated with column experiments. Key results suggest that irreversible chemical adsorption is the dominant mechanism for Cr (VI) adsorption onto the sediment samples. Grain sizes and clay mineral contents are the controlling factors for adsorption capacity. Fine-grained sediments with high clay mineral contents present the highest Cr (VI) adsorption capacity. Chromium (VI) presents high retention on loam and silty loam clay, and high mobility on loamy sand. Results from this study may provide important insight for understanding the transport behaviors of Cr (VI) in shallow aquifers.

ACS Style

Yang Cao; Shuning Dong; Zhenxue Dai; Lin Zhu; Ting Xiao; Xiaoying Zhang; Shangxian Yin; Mohamad Reza Soltanian. Adsorption model identification for chromium (VI) transport in unconsolidated sediments. Journal of Hydrology 2021, 598, 126228 .

AMA Style

Yang Cao, Shuning Dong, Zhenxue Dai, Lin Zhu, Ting Xiao, Xiaoying Zhang, Shangxian Yin, Mohamad Reza Soltanian. Adsorption model identification for chromium (VI) transport in unconsolidated sediments. Journal of Hydrology. 2021; 598 ():126228.

Chicago/Turabian Style

Yang Cao; Shuning Dong; Zhenxue Dai; Lin Zhu; Ting Xiao; Xiaoying Zhang; Shangxian Yin; Mohamad Reza Soltanian. 2021. "Adsorption model identification for chromium (VI) transport in unconsolidated sediments." Journal of Hydrology 598, no. : 126228.

Journal article
Published: 14 March 2021 in Energies
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Mineral reactive surface area (RSA) is one of the key factors that control mineral reactions, as it describes how much mineral is accessible and can participate in reactions. This work aims to evaluate the impact of mineral RSA on numerical simulations for CO2 storage at depleted oil fields. The Farnsworth Unit (FWU) in northern Texas was chosen as a case study. A simplified model was used to screen representative cases from 87 RSA combinations to reduce the computational cost. Three selected cases with low, mid, and high RSA values were used for the FWU model. Results suggest that the impact of RSA values on CO2 mineral trapping is more complex than it is on individual reactions. While the low RSA case predicted negligible porosity change and an insignificant amount of CO2 mineral trapping for the FWU model, the mid and high RSA cases forecasted up to 1.19% and 5.04% of porosity reduction due to mineral reactions, and 2.46% and 9.44% of total CO2 trapped in minerals by the end of the 600-year simulation, respectively. The presence of hydrocarbons affects geochemical reactions and can lead to net CO2 mineral trapping, whereas mineral dissolution is forecasted when hydrocarbons are removed from the system.

ACS Style

Wei Jia; Ting Xiao; Zhidi Wu; Zhenxue Dai; Brian McPherson. Impact of Mineral Reactive Surface Area on Forecasting Geological Carbon Sequestration in a CO2-EOR Field. Energies 2021, 14, 1608 .

AMA Style

Wei Jia, Ting Xiao, Zhidi Wu, Zhenxue Dai, Brian McPherson. Impact of Mineral Reactive Surface Area on Forecasting Geological Carbon Sequestration in a CO2-EOR Field. Energies. 2021; 14 (6):1608.

Chicago/Turabian Style

Wei Jia; Ting Xiao; Zhidi Wu; Zhenxue Dai; Brian McPherson. 2021. "Impact of Mineral Reactive Surface Area on Forecasting Geological Carbon Sequestration in a CO2-EOR Field." Energies 14, no. 6: 1608.

Research article
Published: 14 January 2021 in Environmental Science and Pollution Research
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The relationship between the scale-dependent dispersivity and heterogeneous sedimentary structures is investigated through conducting non-reactive tracer experiments in a three-dimensional heterogeneous sand tank. The heterogeneous porous media consists of three sedimentary facies of silty, fine, and medium sands collected from the west of the Songnen Plain, China. Moreover, several corresponding individual facies soil columns were constructed for comparison. A conservative tracer was continuously injected from an upstream source. The effective parameters were estimated by inverse modeling of a one-dimensional transport model. The results show that the scale dependence of the estimated dispersivities was discovered in the individual facies column (with relatively weaker effect) and the heterogeneous porous media (with more significant effect). With increasing transport distances, the dispersivities of the individual facies tend to reach an asymptotic value, while those of the heterogeneous media increase continuously. Furthermore, the results show that a power function can describe the relationship between effective dispersivities and transport distances. The exponent of the function is greater than one for the heterogeneous media, but less than one for the individual facies. The results also indicate that the dispersion plume is macroscopically dominated by the distribution of facies. The heterogeneity of hydraulic conductivity causes the variations of flow velocity, which further enhances the scale dependence of dispersivities. The tracer experiment in heterogeneous media provides the fundamental insight into the understanding of contaminant transport processes.

ACS Style

Ziqi Ma; Shuning Dong; Shangxian Yin; Zhenxue Dai; Lin Zhu; Wei Jia; Corey Wallace; Mohamad Reza Soltanian. Experimental investigations on scale-dependent dispersivity in three-dimensional heterogeneous porous media. Environmental Science and Pollution Research 2021, 28, 23336 -23348.

AMA Style

Ziqi Ma, Shuning Dong, Shangxian Yin, Zhenxue Dai, Lin Zhu, Wei Jia, Corey Wallace, Mohamad Reza Soltanian. Experimental investigations on scale-dependent dispersivity in three-dimensional heterogeneous porous media. Environmental Science and Pollution Research. 2021; 28 (18):23336-23348.

Chicago/Turabian Style

Ziqi Ma; Shuning Dong; Shangxian Yin; Zhenxue Dai; Lin Zhu; Wei Jia; Corey Wallace; Mohamad Reza Soltanian. 2021. "Experimental investigations on scale-dependent dispersivity in three-dimensional heterogeneous porous media." Environmental Science and Pollution Research 28, no. 18: 23336-23348.

Journal article
Published: 11 January 2021 in Energies
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Control of the grouting pressure within the critical grouting pressure for crack propagation in Ordovician limestone can not only ensure grout penetration length, but also prevent the risk of creating an artificial water channel. Based on the fracture mechanics theory, a formula was proposed to calculate the critical grouting pressure of mixed mode I-II cracks in Ordovician limestone. The necessary conditions for tilted crack opening, the rationality of the existing empirical value of the maximum allowable grouting pressure was investigated based on the mechanical model. The RFPA2D-Flow numerical simulation software was used to evaluate the deduced theory. The research results show that the deduced theoretical calculation formula of the critical grouting pressure agrees with the numerical simulation results; when the mixed mode I-II fracture initiation occurs, the grouting pressure exceeds the perpendicular stress of the overlying rock; the greater the density of the overlying rock mass, the greater the value of grouting pressure for fracture initiation; when the side pressure coefficient was ≥1, crack dip angle increased and the grouting pressure for fracture initiation tended to decrease; and the empirical grouting pressure at the maximum allowable grouting pressure is 2.0–2.5 pw, which will not cause propagation and failure of the existing crack.

ACS Style

Bin Xu; Shuning Dong; Shangxian Yin; Shuxia Li; Yanling Xu; Zhenxue Dai. Analysis of Crack Initiation and Propagation Thresholds of Inclined Cracks under High-Pressure Grouting in Ordovician Limestone. Energies 2021, 14, 360 .

AMA Style

Bin Xu, Shuning Dong, Shangxian Yin, Shuxia Li, Yanling Xu, Zhenxue Dai. Analysis of Crack Initiation and Propagation Thresholds of Inclined Cracks under High-Pressure Grouting in Ordovician Limestone. Energies. 2021; 14 (2):360.

Chicago/Turabian Style

Bin Xu; Shuning Dong; Shangxian Yin; Shuxia Li; Yanling Xu; Zhenxue Dai. 2021. "Analysis of Crack Initiation and Propagation Thresholds of Inclined Cracks under High-Pressure Grouting in Ordovician Limestone." Energies 14, no. 2: 360.

Journal article
Published: 14 December 2020 in Energies
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Potential leakage of reservoir fluids is considered a key risk factor for geologic CO2 sequestration (GCS), with concerns of their chemical impacts on the quality of overlying underground sources of drinking water (USDWs). Effective risk assessment provides useful information to guide GCS activities for protecting USDWs. In this study, we present a quantified risk assessment case study of an active commercial-scale CO2-enhanced oil recovery (CO2-EOR) and sequestration field, the Farnsworth Unit (FWU). Specific objectives of this study include: (1) to quantify potential risks of CO2 and brine leakage to the overlying USDW quality with response surface methodology (RSM); and (2) to identify water chemistry indicators for early detection criteria. Results suggest that trace metals (e.g., arsenic and selenium) are less likely to become a risk due to their adsorption onto clay minerals; no-impact thresholds based on site monitoring data could be a preferable reference for early groundwater quality evaluation; and pH is suggested as an indicator for early detection of a leakage. This study may provide quantitative insight for monitoring strategies on GCS sites to enhance the safety of long-term CO2 sequestration.

ACS Style

Ting Xiao; Brian McPherson; Richard Esser; Wei Jia; Zhenxue Dai; Shaoping Chu; Feng Pan; Hari Viswanathan. Chemical Impacts of Potential CO2 and Brine Leakage on Groundwater Quality with Quantitative Risk Assessment: A Case Study of the Farnsworth Unit. Energies 2020, 13, 6574 .

AMA Style

Ting Xiao, Brian McPherson, Richard Esser, Wei Jia, Zhenxue Dai, Shaoping Chu, Feng Pan, Hari Viswanathan. Chemical Impacts of Potential CO2 and Brine Leakage on Groundwater Quality with Quantitative Risk Assessment: A Case Study of the Farnsworth Unit. Energies. 2020; 13 (24):6574.

Chicago/Turabian Style

Ting Xiao; Brian McPherson; Richard Esser; Wei Jia; Zhenxue Dai; Shaoping Chu; Feng Pan; Hari Viswanathan. 2020. "Chemical Impacts of Potential CO2 and Brine Leakage on Groundwater Quality with Quantitative Risk Assessment: A Case Study of the Farnsworth Unit." Energies 13, no. 24: 6574.

Journal article
Published: 21 September 2020 in Science of The Total Environment
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Bacterial community has been significantly enrolled in the biogeochemical cycling of the coastal subsurface ecosystem. The bacterial community variations with salinity have been extensively investigated in the surface environment, such as lake, soil, and estuary, but not in the subsurface environment. Here we explore the responses of bacterial populations to the salinity and other environmental factors (EFs) by considering both the abundant and rare sub-community in a coastal Holocene groundwater system. Our study results indicate that the bacterial diversity was independent of the salinity in both the abundance and rare sub-community. Besides diversity, no flourishing of abundant bacteria relative abundance is observed with increasing or decreasing salinity. Yet the rare taxa exhibit a bio-growth with salinity, which has a significant correlation (p < 0.001) with sulfate concentration. The responses of the abundant sub-community taxa to nutrients, temperature, pH, and dissolved oxygen are insensitive. However, the correlation between δ18O, δD and the entire community diversity is significant, which demonstrates the bacterial community is affected by the groundwater origin. Besides, not all the species in one class or order are necessarily shaped by the same factor. To quantify the impact of EFs on the community properties, analyses in different taxonomic levels is suggested. These findings imply that the spatial organization of microbial communities is complicated and influenced by multiple factors on a regional scale. The investigated results are useful for understanding biogeochemical processes in the coastal groundwater.

ACS Style

Xiaoying Zhang; Linlin Qi; Wenming Li; Bill X. Hu; Zhenxue Dai. Bacterial community variations with salinity in the saltwater-intruded estuarine aquifer. Science of The Total Environment 2020, 755, 142423 .

AMA Style

Xiaoying Zhang, Linlin Qi, Wenming Li, Bill X. Hu, Zhenxue Dai. Bacterial community variations with salinity in the saltwater-intruded estuarine aquifer. Science of The Total Environment. 2020; 755 ():142423.

Chicago/Turabian Style

Xiaoying Zhang; Linlin Qi; Wenming Li; Bill X. Hu; Zhenxue Dai. 2020. "Bacterial community variations with salinity in the saltwater-intruded estuarine aquifer." Science of The Total Environment 755, no. : 142423.

Journal article
Published: 20 June 2020 in Fuel
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The objective of this work is to evaluate various CO2 sequestration mechanisms occurring in the Morrow B Sandstone in the Farnsworth Unit. A history-matched numerical simulation model was created using extensive geological, petrophysical, and operational data collected from the field. The numerical model is competent to investigate the impact of residual, structural-stratigraphic, solubility, and mineral trapping mechanisms on the fluid transportation dynamics and petrophysical property variations. The model forecasts the field response of 20 years of WAG injections. Afterward, all wells were shut-in, and the reservoir was allowed to evolve for 1000 years to investigate the fate of injected CO2. In this paper, we assess the impacts of various trapping mechanisms on oil recovery and CO2 storage efficacy. By analyzing the results reported from the numerical simulation model, the in-situ fluid composition and mineralogy changes are also investigated. More importantly, we seek to confirm the petrophysical property variations due to the CO2 injection with observations from laboratory measurements. The experiences gained from this study provide valuable insights regarding physiochemical storage induced by the CO2 injection activities and serve as a benchmark case for future CO2 enhanced oil recovery (EOR) projects involving reactive solute transport.

ACS Style

Qian Sun; William Ampomah; Eusebius Junior Kutsienyo; Martin Appold; Benjamin Adu-Gyamfi; Zhenxue Dai; Mohamed Reza Soltanian. Assessment of CO2 trapping mechanisms in partially depleted oil-bearing sands. Fuel 2020, 278, 118356 .

AMA Style

Qian Sun, William Ampomah, Eusebius Junior Kutsienyo, Martin Appold, Benjamin Adu-Gyamfi, Zhenxue Dai, Mohamed Reza Soltanian. Assessment of CO2 trapping mechanisms in partially depleted oil-bearing sands. Fuel. 2020; 278 ():118356.

Chicago/Turabian Style

Qian Sun; William Ampomah; Eusebius Junior Kutsienyo; Martin Appold; Benjamin Adu-Gyamfi; Zhenxue Dai; Mohamed Reza Soltanian. 2020. "Assessment of CO2 trapping mechanisms in partially depleted oil-bearing sands." Fuel 278, no. : 118356.

Tunnel engineering
Published: 01 May 2020 in KSCE Journal of Civil Engineering
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Asymmetric stress occurs in shallow buried highways and railway tunnels. Due to asymmetricalloading, the design process of the tunnel is different from a regular tunnel. Chinese code for designing railway tunnel contains empirical values for different grounding rock to facilitate engineering judgement of asymmetrical loading tunnels based on the slope angle of surface and the burial depth of the tunnel. However, when calculating the asymmetric stress, there seem to be no quantitative criteria for estimating the asymmetric stress. Thus, in this work we create a numerical model to better evaluate the asymmetric stress ratios in different rock types. Our results demonstrate for surrounding rocks of grade V with poor stability, an asymmetrical loading conditions should be considered specifically when the stress ratio at the spandrel is higher than unity. For surrounding rock with grade IV in which stability slightly increases we found that the tunnel is asymmetrical once the stress ratio at the spandrel reaches to above 2 − 3. For the grade IV with a higher stability, an asymmetrical loading should be considered in the design when the stress ratio reaches to 3 − 4. For rock with grade III with the maximum stability only when the stress ratio is higher than 7 − 8, the asymmetrical loading conditions should be considered. We found that for grades III, IV, and V, the stress ratio of sidewall is about unity under various slope angles and burial depth. Importantly, we show that the stress ratio at the sidewall cannot be used to make judgements on whether the shallow buried tunnels are asymmetrical loading conditions. Our results have practical implications in design, safety, and risk analyses of tunnels.

ACS Style

Qingyang Yu; Zeyu Song; Chao Du; Zhenxue Dai; Shangxian Yin; Mohamad Reza Soltanian; Mojtaba Soltanian; Wei Liu. Analysis of Asymmetric Stress Ratio in Shallow Buried Tunnels. KSCE Journal of Civil Engineering 2020, 24, 1924 -1931.

AMA Style

Qingyang Yu, Zeyu Song, Chao Du, Zhenxue Dai, Shangxian Yin, Mohamad Reza Soltanian, Mojtaba Soltanian, Wei Liu. Analysis of Asymmetric Stress Ratio in Shallow Buried Tunnels. KSCE Journal of Civil Engineering. 2020; 24 (6):1924-1931.

Chicago/Turabian Style

Qingyang Yu; Zeyu Song; Chao Du; Zhenxue Dai; Shangxian Yin; Mohamad Reza Soltanian; Mojtaba Soltanian; Wei Liu. 2020. "Analysis of Asymmetric Stress Ratio in Shallow Buried Tunnels." KSCE Journal of Civil Engineering 24, no. 6: 1924-1931.

Journal article
Published: 06 April 2020 in Sustainability
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Soil organic carbon (SOC) mineralization (conversion of carbonaceous material to carbon dioxide) plays a central role in global carbon cycle. However, the effects of SOC mineralization under different saline–alkali stress conditions are poorly understood. In order to understand the carbon mineralization processes, four paddy fields with different saline and alkali degrees were chosen as the experimental samples and the soil CO2 emission fluxes at nine different time steps of the whole simulation experiment were observed. The physical and chemical properties of soils of four field conditions were compared for the dynamic changes of CO2 flux in the progress of paddy field cultivation simulations. The results showed that the first three fields (P1, P2, and P3) were weakly alkaline soils and the last one (P4) was strongly alkaline soil. The SOC content of each plot was significantly different and there was a near-surface enrichment, which was significantly negatively correlated with the degree of alkalization. The accumulation process of the SOC mineralization during the incubation time was consistent with the first-order kinetic model. In the initial stage of mineralization, the amount of CO2 released massively, and then the release intensity decreased rapidly. The mineralization rate decreased slowly with time and finally reached a minimum at the end of the incubation period. This study indicates that the SOC mineralization process is affected by a variety of factors. The main factors influencing SOC mineralization in the saline–alkaline soils are the exchangeable sodium percentage (ESP), followed by enzyme activities. Salinization of the soils inhibits the rate of soil carbon cycle, which has a greater impact on the carbon sequestration than on the carbon source process. The intensity and completeness of the SOC mineralization reactions increase with increasing SOC contents and decrease with increasing ESP levels.

ACS Style

Sining Wang; Jie Tang; Zhaoyang Li; Yuqing Liu; Zihao Zhou; Jingjing Wang; Yunke Qu; Zhenxue Dai. Carbon Mineralization under Different Saline—Alkali Stress Conditions in Paddy Fields of Northeast China. Sustainability 2020, 12, 2921 .

AMA Style

Sining Wang, Jie Tang, Zhaoyang Li, Yuqing Liu, Zihao Zhou, Jingjing Wang, Yunke Qu, Zhenxue Dai. Carbon Mineralization under Different Saline—Alkali Stress Conditions in Paddy Fields of Northeast China. Sustainability. 2020; 12 (7):2921.

Chicago/Turabian Style

Sining Wang; Jie Tang; Zhaoyang Li; Yuqing Liu; Zihao Zhou; Jingjing Wang; Yunke Qu; Zhenxue Dai. 2020. "Carbon Mineralization under Different Saline—Alkali Stress Conditions in Paddy Fields of Northeast China." Sustainability 12, no. 7: 2921.

Research article
Published: 24 February 2020 in Energy & Fuels
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CO2 dissolution in water at different pressure and temperature conditions is one of the most essential issues to CO2 geological sequestration in brine aquifers. In this manuscript, four powerful Machine Learning (ML) techniques including Radial Basis Function Neural Network (RBFNN), Least Square Support Vector Machine (LSSVM), Multilayer Perceptron (MLP), and Gene Expression Programming (GEP), are utilized to generate economic, rapid and reliable models to predict CO2 solubility in water to 3500 bar and 623.15 K. To expand the prediction capability of the ML approaches, their control parameters are optimized by various techniques. Four backpropagation algorithms, are applied in the MLP learning phase, while Differential Evolution (DE), Particle Swarm Optimization (PSO), Firefly Algorithm (FFA), and Genetic Algorithm (GA) are used to optimize the RBFNN and LSSVM control parameters. A wide-ranged database including temperature and pressure as inputs and CO2 solubility in pure water as output, is utilized to develop the models. Statistical quality measures and visual error analyses are used to examine the robustness of the established models. Results demonstrate that the prediction capability of the proposed models is quite satisfactory. In addition, the inter-comparison results reveal that the LSSVM-FFA is the best paradigm, as it outperforms the other proposed ML techniques as well as prior models. The overall RMSE and R2 values of the implemented LSSVM-FFA are 0.3261 and 0.9930, respectively. Finally, the Leverage approach is conducted to check the quality of the employed data and to define the applicability realm of the LSSVM-FFA model.

ACS Style

Abdolhossein Hemmati Sarapardeh; Menad Nait Amar; Mohamad Reza Soltanian; Zhenxue Dai; Xiaoying Zhang. Modeling CO2 Solubility in Water at High Pressure and Temperature Conditions. Energy & Fuels 2020, 34, 4761 -4776.

AMA Style

Abdolhossein Hemmati Sarapardeh, Menad Nait Amar, Mohamad Reza Soltanian, Zhenxue Dai, Xiaoying Zhang. Modeling CO2 Solubility in Water at High Pressure and Temperature Conditions. Energy & Fuels. 2020; 34 (4):4761-4776.

Chicago/Turabian Style

Abdolhossein Hemmati Sarapardeh; Menad Nait Amar; Mohamad Reza Soltanian; Zhenxue Dai; Xiaoying Zhang. 2020. "Modeling CO2 Solubility in Water at High Pressure and Temperature Conditions." Energy & Fuels 34, no. 4: 4761-4776.

Journal article
Published: 21 February 2020 in Fuel
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Permeability is an important hydrogeological parameter for the quantitative evaluation of water resources and prediction of water inflow. In this study, we examine a typical water-bearing sandstone obtained in North China to explore the correlation between the microscopic pore characteristics and macroscopic permeability of the sandstone. In addition, pixel-level annotated data are generated from the images obtained in electron microscopy experiments for deep learning training. Using the deep learning framework, we analyse the pore characteristics through semantic image segmentation based on artificial intelligence and explore the relationship between the microscopic pore characteristics and the macroscopic permeability parameters of the sandstone. This method addresses the limitations of traditional image recognition methods, such as the inability to obtain the complete pore space characteristics in scanning electron microscopy (SEM) images as well as poor segmentation and low accuracy. Moreover, this method can be used to realise the full benefits of accurate image recognition, and it enables the automatic processing of microscopic images to significantly improve the accuracy of pore identification in rock samples.

ACS Style

Qingyang Yu; Ziwei Xiong; Chao Du; Zhenxue Dai; Mohamad Reza Soltanian; Mojtaba Soltanian; Shangxian Yin; Wei Liu; Chen Liu; Chengbin Wang; Zeyu Song. Identification of rock pore structures and permeabilities using electron microscopy experiments and deep learning interpretations. Fuel 2020, 268, 117416 .

AMA Style

Qingyang Yu, Ziwei Xiong, Chao Du, Zhenxue Dai, Mohamad Reza Soltanian, Mojtaba Soltanian, Shangxian Yin, Wei Liu, Chen Liu, Chengbin Wang, Zeyu Song. Identification of rock pore structures and permeabilities using electron microscopy experiments and deep learning interpretations. Fuel. 2020; 268 ():117416.

Chicago/Turabian Style

Qingyang Yu; Ziwei Xiong; Chao Du; Zhenxue Dai; Mohamad Reza Soltanian; Mojtaba Soltanian; Shangxian Yin; Wei Liu; Chen Liu; Chengbin Wang; Zeyu Song. 2020. "Identification of rock pore structures and permeabilities using electron microscopy experiments and deep learning interpretations." Fuel 268, no. : 117416.

Journal article
Published: 07 January 2020 in Journal of Hydrology
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The potential impacts of the spatial resolution of sedimentary structure data on solute dispersion in heterogeneous porous formations are investigated with Lagrangian-based transport models. The models rely on a covariance function that represent a hierarchical organization of sedimentary facies types by using facies physical properties, such as volume proportions and mean length as well as auto- and cross-transition probabilities and their log-permeability covariance. A detailed sedimentary architecture data (i.e. indicator data) provides better representation of the spatial correlation structures of the global covariances through capturing its underlying structure defined by transition probabilities more accurately. However, the extent to which such data affect time-dependent transport parameters (i.e. dispersivity) is unclear. In this study, we parameterize transport models using detailed collocated sedimentary architecture and permeability data from an outcrop in Española Basin, NM. In addition, we perform global sensitivity analysis based on Polynomials Chaos Expansion to understand the significance of parameters in the transport models. The results show that dispersivity and particle displacement variance are under-estimated if less resolved facies (i.e. indicator) data are used even if the global covariance structure is well captured. Dispersivity is sensitive to the correlation scale that is directly calculated from sedimentary architecture data, and the mean log-permeability. However, anisotropy ratio and mean log-permeability are the most sensitive parameters for the transverse dispersivity.

ACS Style

Zhenxue Dai; Chuanjun Zhan; Shuning Dong; Shangxian Yin; Xiaoying Zhang; Mohamad Reza Soltanian. How does resolution of sedimentary architecture data affect plume dispersion in multiscale and hierarchical systems? Journal of Hydrology 2020, 582, 124516 .

AMA Style

Zhenxue Dai, Chuanjun Zhan, Shuning Dong, Shangxian Yin, Xiaoying Zhang, Mohamad Reza Soltanian. How does resolution of sedimentary architecture data affect plume dispersion in multiscale and hierarchical systems? Journal of Hydrology. 2020; 582 ():124516.

Chicago/Turabian Style

Zhenxue Dai; Chuanjun Zhan; Shuning Dong; Shangxian Yin; Xiaoying Zhang; Mohamad Reza Soltanian. 2020. "How does resolution of sedimentary architecture data affect plume dispersion in multiscale and hierarchical systems?" Journal of Hydrology 582, no. : 124516.

Technical report
Published: 08 February 2019 in Special Analysis: 2016-002, Analysis of Cover Erosion and Enhanced Infiltration at Pit 25, TA-54 Area G
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The U.S. Department of Energy's Office of Scientific and Technical Information

ACS Style

Kay Hanson Birdsell; Zhenxue Dai; Philip H. Stauffer; Sean B. French. Special Analysis: 2016-002, Analysis of Cover Erosion and Enhanced Infiltration at Pit 25, TA-54 Area G. Special Analysis: 2016-002, Analysis of Cover Erosion and Enhanced Infiltration at Pit 25, TA-54 Area G 2019, 1 .

AMA Style

Kay Hanson Birdsell, Zhenxue Dai, Philip H. Stauffer, Sean B. French. Special Analysis: 2016-002, Analysis of Cover Erosion and Enhanced Infiltration at Pit 25, TA-54 Area G. Special Analysis: 2016-002, Analysis of Cover Erosion and Enhanced Infiltration at Pit 25, TA-54 Area G. 2019; ():1.

Chicago/Turabian Style

Kay Hanson Birdsell; Zhenxue Dai; Philip H. Stauffer; Sean B. French. 2019. "Special Analysis: 2016-002, Analysis of Cover Erosion and Enhanced Infiltration at Pit 25, TA-54 Area G." Special Analysis: 2016-002, Analysis of Cover Erosion and Enhanced Infiltration at Pit 25, TA-54 Area G , no. : 1.

Journal article
Published: 04 February 2019 in Scientific Reports
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This study investigates multiple types of water resources in the western mining area in China, their supply-demand balance by using the same dimension gray recurrence dynamic model GM (1, 1), and water content coefficients of mines to ease water supply-demand contradiction. A multi-objective programming model is proposed for optimal water resources allocation management. Optimal technical schemes for water resources allocation among different users are obtained. The optimization model improves upon the previous studies by using water demand and water supply forecast. Coordinated development for mining safety, mine water utilization, and remediation and control of water environment is achieved.

ACS Style

Shuning Dong; Bin Xu; Shangxian Yin; Yong Han; Xiaodong Zhang; Zhenxue Dai. Water Resources Utilization and Protection in the Coal Mining Area of Northern China. Scientific Reports 2019, 9, 1 -10.

AMA Style

Shuning Dong, Bin Xu, Shangxian Yin, Yong Han, Xiaodong Zhang, Zhenxue Dai. Water Resources Utilization and Protection in the Coal Mining Area of Northern China. Scientific Reports. 2019; 9 (1):1-10.

Chicago/Turabian Style

Shuning Dong; Bin Xu; Shangxian Yin; Yong Han; Xiaodong Zhang; Zhenxue Dai. 2019. "Water Resources Utilization and Protection in the Coal Mining Area of Northern China." Scientific Reports 9, no. 1: 1-10.