Engineering topics

Liu, Ning

Publications and source records attributed to Liu, Ning.

At least 55 records · Page 3

DOE OSTI2019

Cardiac Reprogramming Factors Synergistically Activate Genome-wide Cardiogenic Stage-Specific Enhancers

The cardiogenic transcription factors (TFs) Mef2c, Gata4, and Tbx5 can directly reprogram fibroblasts to induced cardiac-like myocytes (iCLMs), presenting a potential source of cells for cardiac repair. While activity of these TFs is enhanced by Hand2 and Akt1, their genomic targets and interactions during reprogramming are not well studied. We performed genome-wide analyses of cardiogenic TF binding and enhancer profiling during cardiac reprogramming. We found that these TFs synergistically activate enhancers highlighted by Mef2c binding sites and that Hand2 and Akt1 coordinately recruit other TFs to enhancer elements. Intriguingly, these enhancer landscapes collectively resemble patterns of enhancer activation during embryonic cardiogenesis. We further constructed a cardiac reprogramming gene regulatory network and found repression of EGFR signaling pathway genes. Consistently, chemical inhibition of EGFR signaling augmented reprogramming. Thus, by defining epigenetic landscapes these findings reveal synergistic transcriptional activation across a broad landscape of cardiac enhancers and key signaling pathways that govern iCLM reprogramming.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2019

The effect of foam quality, particle concentration and flow rate on nanoparticle-stabilized CO 2 mobility control foams

CO 2 foam is regarded as a promising technology and widely used in the oil and gas industry, not only to improve oil production, but also to mitigate carbon emissions through their capture. This paper describes a series of nanoparticle-stabilized CO 2 foam generation and foam flow experiments under reservoir conditions. Stable CO 2 foam was generated when CO 2 and a nanosilica dispersion flowed through the core sample under 1500 psi and 25 °C. The foam changed from a fine-texture foam to a coarse foam as the foam quality increased from 20% to 95%. Foam mobility increased slightly with the increasing foam quality from 20% to 80% and then rapidly from 80% to 95%. A stable CO 2 foam was generated as the nanosilica concentration increased to 2500 ppm. Foam mobility and resistance factor increased with the increasing nanosilica concentration. As the injection flow rate increased to 60 ml h -1 , stable and fine-texture CO 2 foam was obtained. Foam mobility was observed to remain almost constant as the injection flow rate increased from 60 ml h -1 to 150 ml h -1 .

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2018

Mechanisms of Semiconducting 2H to Metallic 1T Phase Transition in Two-dimensional MoS 2 Nanosheets

In the present work, phase transition mechanisms from semiconducting 2H phase to metallic 1T phase in MoS 2 nanosheets were studied using density functional theory (DFT) method. Various 2H→1T phase transition mechanisms that consist of nucleation and propagation steps, which simulated by collective rotational and rotational/translational movements, single atom translational movement, as well as the gliding movement of one row for sulfur (S) atoms, on both the basal plane and Mo- and S-edges with different S coverages were investigated. On the perfect basal plane, the 1T phase nucleation is unlikely due to the extremely high barrier of 2.25 eV/atom. Whereas the presence of defective S vacancies on the basal plane dramatically facilitate the 1T phase nucleation and propagation around the defective sites by the collective rotational movement of three S atoms. On the 2H phase basal plane with two S vacancies, the kinetic barriers for the 1T phase nucleation are as low as of 0.66~0.77 eV/atom. Like the promoting effect of S vacancies on the phase transition over the basal plane, DFT results suggest that the S coverage on the Mo- and S-edges will affect the 1T phase nucleation and propagation. The 1T phase nucleation starting with the translational movement of single S atom on the bare Mo-edge and the gliding movement of an entire row of S atoms on the S-edge with 50%S coverage are kinetically favorable. While the 1T phase formation at the Mo-edge with 50%S coverage and the S-edge with 100% S coverage are unlikely. The present work not only confirms the important role of S vacancies/coverages in the 2H-1T phase transition, but also provides new insight into how and where the 2H-1T phase transition occurs at the atomic level, which also sheds light on the general phase transition mechanism for two-dimensional transition metal dichalcogenide materials. The work was financially supported by the National Natural Science Foundation of China (No. 21476012, 21571012, and 91534201). Q. Jin appreciates the joint Ph.D. scholarship support from the China Scholarship Council. The computing time was granted by a scientific theme user proposal in the William R. Wiley Environmental Molecular Sciences Laboratory (EMSL), which is a U.S. Department of Energy national scientific user facility located at PNNL in Richland, Washington. D. Mei is supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences & Biosciences.

Molybdenum disulfide, phase transition, sulfur vac↗

DOE OSTI2018

Low dose Emodin induces tumor senescence for boosting breast cancer chemotherapy via silencing NRARP

Highlights: • The chemoresistance often limits clinical effectiveness of chemotherapy on breast cancer treatment. • Emodin potentiates 5-FU-induced apoptosis of breast cancer cells. • Low dose Emodin induces cellular senescence in breast cancer cells by inhibition of Nrarp. The resistance to 5-FU often limits its clinical effectiveness on breast cancer treatment. Combination therapy thus is employed to overcome this treatment resistance. We here report a potent antitumor effect of Emodin at low dose on chemotherapy sensitivity of MCF-7 breast cancer cells.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2018

Nucleation of Cu n ( n = 1–5) Clusters and Equilibrium Morphology of Cu Particles Supported on CeO 2 Surface: A Density Functional Theory Study

In the present work, the interactions between Cun (n=1~4) clusters and three low-index structural CeO2 (111, 110, 100) surfaces were investigated using density functional theory calculations. The atomic Cu prefers to aggregate into large clusters on the CeO2(111) surface while it is unfavorable on both CeO2(110) and CeO2(100) surfaces. Once the planar Cu4-p cluster is formed, it would convert into the 3D tetrahedral Cu4-t cluster on CeO2(110) and CeO2(111) surfaces, i.e., 2D to 3D transition growth is thermodynamically favorable and kinetically feasible on CeO2(110) and CeO2(111) surfaces. The effects of ceria support structure on the morphology of the large Cu nanoparticle was examined using calculated adhesion and interfacial energies of periodic Cu(khl)/CeO2 model systems. The calculated macroscopic contact angles (? > 100?) of various model systems suggest that the supported Cu nanoparticle is in bad wetting condition. Finally, the morphologies of large Cu nanoparticles on different CeO2 surfaces were predicted using Wulff-Kaichew construction principle.

Cu/CeO2 catalyst, Adsorption and nucleation, DFT c↗

DOE OSTI2018

Construction of N-doped TiO2/MoS2 heterojunction with synergistic effect for enhanced visible photodegradation activity

Highlights: • An N-doped TiO{sub 2}/MoS{sub 2} heterojunction is successfully synthesized by a hydrothermal method. • N-doped TiO{sub 2}/MoS{sub 2} heterojunction photocatalyst exhibits enhanced visible photodegradation activity. • The synergistic effect is between N-doping and coupling with MoS{sub 2}. • Superoxide radicals (O{sub 2}{sup −}) and photogenerated holes (h{sup +}) are chiefly responsible for the degradation process. - Abstract: An N-doped TiO{sub 2}/MoS{sub 2} heterojunction photocatalyst constructed by two-dimension MoS{sub 2} nanosheets and N-doped TiO{sub 2} nanoparticles was successfully synthesized by a hydrothermal method. The synthesized N-TiO{sub 2}/MoS{sub 2} composites were characterized by XRD, XPS, TEM, UV–vis DRS and PL, and its visible photocatalytic activity was evaluated by degradation of methylene blue. The results showed that N-doped TiO{sub 2}/MoS{sub 2} heterojunction photocatalyst achieved more enhanced photocatalytic activity compared with pure TiO{sub 2}, MoS{sub 2} and N-doped TiO{sub 2} for degradation of MB. Trapping tests with different scavengers indicated that not hydroxyl radicals (OH) but superoxide radicals (O{sub 2}{sup −}) and photogenerated holes (h{sup +}) were highly responsible for the degradation process. The reusable experiments showed that the prepared N-doped TiO{sub 2}/MoS{sub 2} heterojunction photocatalyst was stable during the photodegradation of MB and will have practical applications for environmental remediation.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

DOE OSTI2018

Functional metagenomics reveals abundant polysaccharide-degrading gene clusters and cellobiose utilization pathways within gut microbiota of a wood-feeding higher termite

Plant cell-wall polysaccharides constitute the most abundant but recalcitrant organic carbon source in nature. Microbes residing in the digestive tract of herbivorous bilaterians are particularly efficient at depolymerizing polysaccharides into fermentable sugars and play a significant support role towards their host’s lifestyle. Here, we combine large-scale functional screening of fosmid libraries, shotgun sequencing, and biochemical assays to interrogate the gut microbiota of the wood-feeding “higher” termite Globitermes brachycerastes. A number of putative polysaccharide utilization gene clusters were identified with multiple fibrolytic genes. Our large-scale functional screening of 50,000 fosmid clones resulted in 464 clones demonstrating plant polysaccharide-degrading activities, including 267 endoglucanase-, 24 exoglucanase-, 72 β-glucosidase-, and 101 endoxylanase-positive clones. We sequenced 173 functionally active clones and identified ~219 genes encoding putative carbohydrate-active enzymes (CAZymes) targeting cellulose, hemicellulose and pectin. Further analyses revealed that 68 of 154 contigs encode one or more CAZyme, which includes 35 examples of putative saccharolytic operons, suggesting that clustering of CAZymes is common in termite gut microbial inhabitants. Biochemical characterization of a representative xylanase cluster demonstrated that constituent enzymes exhibited complementary physicochemical properties and saccharolytic capabilities. Furthermore, diverse cellobiose-metabolizing enzymes include β-glucosidases, cellobiose phosphorylases, and phopho-6-β-glucosidases were identified and functionally verified, indicating that the termite gut micro-ecosystem utilizes diverse metabolic pathways to interconnect hydrolysis and central metabolism. Collectively, these results provide an in-depth view of the adaptation and digestive strategies employed by gut microbiota within this tiny-yet-efficient host-associated ecosystem.

59 BASIC BIOLOGICAL SCIENCES↗

DOE OSTI2018

A Theoretical Study on Reaction Mechanisms and Kinetics of Thiophene Hydrodesulfurization over MoS 2 Catalysts

In the present work, thiophene hydrodesulphurization (HDS) over the Mo-edge, the S-edge, and the Mo-S connection edge of MoS 2 catalyst with 50% sulfur coverage was studied using first-principles based microkinetic modeling. Two parallel HDS routes, i.e., direct desulfurization (DDS) and hydrogenation (HYD) were taken into account. It has been found that the major reaction route of thiophene HDS on the Mo- and the Mo-S edges is temperature dependent. In the low temperature range of 500~600 K, the HYD route is dominant, leading to the C 4 H 8 formation. As the temperature increases, the DDS route becomes competitive with the HYD route. At the temperature above 650 K, the DDS route will be the dominant HDS reaction route on the Mo- and the Mo-S edges. While the DDS route that leads to the formation of C4H6 is the major thiophene HDS reaction route on the S-edge in the entire temperature range of 500~750 K. The microkinetic modeling results show the overall HDS activity on the S-edge is lower than it on the Mo- and the Mo-S edges. The Mo-S edge also provides a preferential reaction pathway, which facilitates 2-hydrothiophene migration from the Mo-edge to the S-edge, followed by remaining elementary steps with lower activation barriers in the DDS route. The work was financially supported by the National Natural Science Foundation of China (No. 21476012, 21571012, 21407007 and 91534201). The computing time was granted by a scientific theme user proposal in the William R. Wiley Environmental Molecular Sciences Laboratory (EMSL), which is a U.S. Department of Energy national scientific user facility located at Pacific Northwest National Laboratory (PNNL) in Richland, Washington. Part of computing time was provided the National Energy Research Scientific Computing Center (NERSC). D. Mei is supported by the US Department of Energy, Office of Sciences, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences & Biosciences.

Thiophene, hydrodesulphurization, MoS2, DFT, micro↗

DOE OSTI2018

Stable cycling of high-voltage lithium metal batteries in ether electrolytes

The development of functional electrolytes that are stable with both the lithium (Li) anode and the 4-V cathode is of significant importance to enable long-term cycling stability of high-voltage Li metal batteries. Due to their limited oxidative stability (< 4 V), ethers have been excluded from being used in high-voltage batteries for a long time, in spite of their superior reductive stability against Li metal compared to the conventional organic carbonate electrolytes. Here we report a concentrated dual-salt/ether electrolyte design that can form stable interfacial layers on both the high-voltage LiNi1/3Mn1/3Co1/3O2 cathode and the Li metal anode, thus realizing an unprecedented capacity retention >90% over 300 cycles with a charge cut-off voltage of 4.3 V. This study offers a promising approach to enabling ether electrolytes for high-voltage applications, expanding a new spectrum of solvent choices for high-voltage Li metal batteries.

Ether electrolyte, high concentration, high voltag↗

DOE OSTI2018

Emergence of Uranium as a Distinct Metal Center for Building Intrinsic X‐ray Scintillators

Abstract The combination of high atomic number and high oxidation state in U VI materials gives rise to both high X‐ray attenuation efficiency and intense green luminescence originating from ligand‐to‐metal charge transfer. These two features suggest that U VI materials might act as superior X‐ray scintillators, but this postulate has remained substantially untested. Now the first observation of intense X‐ray scintillation in a uranyl–organic framework ( SCU‐9 ) that is observable by the naked eye is reported. Combining the advantage in minimizing the non‐radiative relaxation during the X‐ray excitation process over those of inorganic salts of uranium, SCU‐9 exhibits a very efficient X‐ray to green light luminescence conversion. The luminescence intensity shows an essentially linear correlation with the received X‐ray intensity, and is comparable with that of commercially available CsI:Tl. SCU‐9 possesses an improved X‐ray attenuation efficiency ( E >20 keV) as well as enhanced radiation resistance and decreased hygroscopy compared to CsI:Tl.

Wang, Yaxing↗

DOE OSTI2018

Emergence of Uranium as a Distinct Metal Center for Building Intrinsic X-ray Scintillators

The combination of high atomic number and high oxidation state in U VI materials gives rise to both high X-ray attenuation efficiency and intense green luminescence originating from ligand-to-metal charge transfer. These two features suggest that U VI materials might act as superior X-ray scintillators, but this postulate has remained substantially untested. Now the first observation of intense X-ray scintillation in a uranyl–organic framework (SCU-9) that is observable by the naked eye is reported. Combining the advantage in minimizing the non-radiative relaxation during the X-ray excitation process over those of inorganic salts of uranium, SCU-9 exhibits a very efficient X-ray to green light luminescence conversion. The luminescence intensity shows an essentially linear correlation with the received X-ray intensity, and is comparable with that of commercially available CsI:Tl. SCU-9 possesses an improved X-ray attenuation efficiency (E>20 keV) as well as enhanced radiation resistance and decreased hygroscopy compared to CsI:Tl.

Chemistry↗

DOE OSTI2018

Natural Product Micheliolide (MCL) Irreversibly Activates Pyruvate Kinase M2 and Suppresses Leukemia

Metabolic reprogramming of cancer cells is essential for tumorigenesis in which pyruvate kinase M2 (PKM2), the low activity isoform of pyruvate kinase, plays a critical role. Herein, we describe the identification of a nature-product-derived micheliolide (MCL) that selectively activates PKM2 through the covalent binding at residue cysteine424 (C424), which is not contained in PKM1. This interaction promotes more tetramer formation, inhibits the lysine433 (K433) acetylation, and influences the translocation of PKM2 into the nucleus. In addition, the pro-drug dimethylaminomicheliolide (DMAMCL) with similar properties as MCL significantly suppresses the growth of leukemia cells and tumorigenesis in a zebrafish xenograft model. Cell-based assay with knock down PKM2 expression verifies that the effects of MCL are dependent on PKM2 expression. DMAMCL is currently in clinical trials in Australia. Our discovery may provide a valuable pharmacological mechanism for clinical treatment and benefit the development of new anticancer agents.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2018

g-C3N4/UiO-66 nanohybrids with enhanced photocatalytic activities for the oxidation of dye under visible light irradiation

Highlights: • G-C{sub 3}N{sub 4}/UiO-66 heterojunctions were synthesized by a facile one-pot method. • G-C{sub 3}N{sub 4}/UiO-66 nanohybrids were used as an visible-light-driven photocatalysts. • G-C{sub 3}N{sub 4}/UiO-66 nanohybrids enhanced the separation of photoexcited carriers. • G-C{sub 3}N{sub 4}/UiO-66 nanohybrids were stable even after the four cycles. - Abstract: In this study, g-C{sub 3}N{sub 4} nanosheets coated UiO-66 nanohybrids were fabricated via a simple solvothermal method. The physicochemical parameters, structural and electrochemical properties of g-C{sub 3}N{sub 4}/UiO-66 nanohybrids (CNUO-x) were investigated. The nanohybrids were systematically characterized by XRD, FT-IR, TGA, TEM, SEM, EDS elemental mappings, XPS, N{sub 2} adsorption-desorption isotherms, PL and DRS. It was found that the addition of moderate g-C{sub 3}N{sub 4} could enhance the separation and migration rate of photo-induced charges, consequently leading to the increase of photocatalytic efficiency. The CNUO-1 nanohybrid exhibited better photocatalytic activity for the oxidation of Rh B under visible light irradiation, and displayed about 6.0 and 3.3 times faster than that of g-C{sub 3}N{sub 4} and UiO-66, respectively. Meanwhile, the nanohybrid showed excellent stability and reusability in four cyclic experiments. Finally, the increased photocatalytic reaction mechanism was also proposed. O{sub 2}{sup −}, h{sup +} and OH were further found to be the main active contributors.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

DOE OSTI2018

Facile and Efficient Decontamination of Thorium from Rare Earths Based on Selective Selenite Crystallization

The coexistence of radioactive contaminants (e.g., thorium, uranium, and their daughters) in rare earth minerals introduces significant environmental, economic, and technological hurdles in modern rare earth production. Capable, low cost, and green decontamination strategies are therefore desired to ameliorate this problem. In this work, we report a single-step and quantitative decontamination strategy of thorium from rare earths based on a unique periodic trend in the formation of crystalline selenite compounds across the lanthanide series, where Ce(III) is fully oxidized in situ to Ce(IV). This gives rise to a crystallization system that is highly selective to trap tetravalent f-blocks while all other trivalent lanthanides completely remain in solution when coexist. These findings are bolstered by first-principles calculations of lattice energies and an examination of bonding in these compounds. This system is contrasted with typical natural and synthetic systems, where trivalent and tetravalent f-block elements often cocrystallize. The separation factors after one round of crystallization were determined from binary systems of Th(IV)/La(III), Th(IV)/Eu(III), and Th(IV)/Yb(III) to reach 2.1 × 10 5 , 1.2 × 10 5 , and 9 × 10 4 , respectively. Selective crystallization of thorium from a simulated monazite composite yields a separation factor of 1.9 × 10 3 with nearly quantitative removal of thorium.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗

DOE OSTI2018

Theoretical Investigation of the Structural Stabilities of Ceria Surfaces and Supported Metal Nanocluster in Vapor and Aqueous Phases

Understanding the structural stability and dynamics at the interface between the solid metal oxide and aqueous phase is significant in a variety of industrial applications including heterogeneous catalysis and environmental remediation. In the present work, the stabilities of three low-index ceria (CeO2) surfaces, i.e., (111), (110) and (100) in vapor and aqueous phases were studied using ab initio molecular dynamics simulations and density functional theory (DFT) calculations. Gibbs surface free energies as a function of temperature, water partial pressure, and water coverages were calculated using DFT based atomistic thermodynamic approach. On the basis of surface free energies, the morphology and exposed surface structures of the CeO2 nanoparticle were predicted using Wulff construction principle. It is found that the partially hydroxylated (111) and (100) are two major surface structures of CeO2 nanoparticles in vapor phase at ambient temperature (300 K). As the temperature increases, the fully dehydrated (111) surface gradually becomes the most dominant surface structure. While in aqueous phase, the exposed surface of the CeO2 nanoparticle is dominated by the hydroxylated (110) structure at 393 K. Finally, the morphology and stability of a cuboctahedron Pt13 nanocluster supported on CeO2 surfaces in both gas and aqueous phases were investigated. In gas phase, the supported Pt13 nanocluster has the tendency to wetting the CeO2 surface due to the strong metal-support interaction. The calculated interaction energies suggest the CeO2(110) surface provides the best stability for the Pt13 nanocluster. The CeO2 supported Pt13 nanoclusters are oxidized. Compared to the gas phase, the morphology of the CeO2 supported Pt13 nanocluster is less distorted due to the solvation effect provided by surrounding water molecules in aqueous phase. More electrons are transferred from the Pt13 nanocluster to the CeO2 support, implying the supported Pt13 nanocluster is further oxidized in aqueous phase.

ab initio molecular dynamics simulation↗

DOE OSTI2018

Effects of Imide–Orthoborate Dual-Salt Mixtures in Organic Carbonate Electrolytes on the Stability of Lithium Metal Batteries

The effects of lithium imide and lithium orthoborate dual-salt electrolytes of different salt chemistries in carbonate solvents on the cycling stability of Li metal batteries were systematically and comparatively investigated. Two imide salts (LiTFSI and LiFSI) and two orthoborate salts (LiBOB and LiDFOB) were chosen for this study and compared with the conventional LiPF6 salt. The cycling stability of the Li metal cells with the electrolytes follows the order from good to poor as LiTFSI-LiBOB > LiTFSI-LiDFOB > LiPF6 > LiFSI-LiBOB > LiFSI-LiDFOB, indicating that LiTFSI behaves better than LiFSI and LiBOB over LiDFOB in these four dual-salt mixtures. The LiTFSI-LiBOB can effectively protect the Al substrate and form a more robust surface film on Li metal anode, while the LiFSI-LiBOB results in serious corrosion to the stainless steel cell case and a thicker and looser surface film on Li anode. Computational calculations indicate that the chemical and electrochemical stabilities also follow the order of LiTFSI-LiBOB > LiTFSI-LiDFOB > LiFSI-LiBOB > LiFSI-LiDFOB. The key findings of this work emphasize that the salt chemistry is critically important for enhancing the interfacial stability of Li metal anode and should be carefully manipulated in the development of high performance Li metal batteries.

Li metal batteries, dual-salt electrolyte, solid e↗

DOE OSTI2018

Machine Protection System Research and Development for the Fermilab PIP-II Proton Linac

PIP-II is a high intensity proton linac being design to support a world-leading physics program at Fermilab. Initially it will provide high intensity beams for Fermilab's neutrino program with a future extension to other applications requiring an upgrade to CW linac operation (e.g. muon experiments). The machine is conceived to be 2 mA CW, 800 MeV H⁻ linac capable of working initially in a pulse (0.55 ms, 20 Hz) mode for injection into the existing Booster. The planned upgrade to CW operation implies that the total beam current and damage potential will be greater than in any present HEP hadron linac. To mitigate the primary technical risk and challenges associated PIP-II an integrated system test for the PIP-II front-end technology is being developed. As part of the R&D a robust machine protection system (MPS) is being designed. This paper describes the progress and challenges associated with the MPS.

43 PARTICLE ACCELERATORS↗

DOE OSTI2017

Numerical Modeling of CO 2 and Brine Leakage through Open Fracture in a Fault Zone: Open Channel Flow or Darcy Flow

Understanding fluids migration and leakage risk along the fault zone is necessary to guarantee the safety of CO 2 geological storage. The validity of Darcy’s law gets challenged in dealing with the flow in open fractures since the occurring of turbulence flow. In this study, we develop a 2D model with usage of T2Well, an integrated wellbore-reservoir simulator, to investigate the leakage problem along open fractures which are embedded in a fault zone from the deep injection reservoir to shallow aquifers. The results record a positive feedback of gas expansion and pressure response in fracture, which causes a quick downward propagation of highly gas saturated zone from the top of fracture and an easy gas breakthrough in the shallower aquifers. The decreasing of aperture size of fracture significantly enhances the leakage rates in fracture, but with less influences as aperture increases. In comparison, the Equivalent Porous Media models show a good approximation with the momentum model of large apertures but poor for the small one. Nevertheless, the differences are small in terms of final CO 2 distribution among various aquifers, suggesting that Darcy’s law may be still “effective” in solving flow problem along fractures in a constant injection system at a large time scale.

58 GEOSCIENCES↗