Comparative analysis of thermodynamic and mechanical responses between underground hydrogen storage and compressed air energy storage in lined rock caverns

Underground hydrogen storage(UHS)and compressed air energy storage(CAES)are two viable largescale energy storage technologies for mitigating the intermittency of wind and solar power.Therefore,it is meaningful to compare the properties of hydrogen and air with typical thermodynamic storage processes.This study employs a multi-physical coupling model to compare the operations of CAES and UHS,integrating gas thermodynamics within caverns,thermal conduction,and mechanical deformation around rock caverns.Gas thermodynamic responses are validated using additional simulations and the field test data.Temperature and pressure variations of air and hydrogen within rock caverns exhibit similarities under both adiabatic and diabatic simulation modes.Hydrogen reaches higher temperature and pressure following gas charging stage compared to air,and the ideal gas assumption may lead to overestimation of gas temperature and pressure.Unlike steel lining of CAES,the sealing layer(fibre-reinforced plastic FRP)in UHS is prone to deformation but can effectively mitigates stress in the sealing layer.In CAES,the first principal stress on the surface of the sealing layer and concrete lining is tensile stress,whereas UHS exhibits compressive stress in the same areas.Our present research can provide references for the selection of energy storage methods.

A first-principles study of helium diffusion in quartz and coesite under high pressure up to 12GPa

Helium diffusion in mantle minerals is crucial for understanding mantle structure and the dynamic processes of Earth's degassing.In this paper,we report helium incorporation and the mechanism of its diffusion in perfect crystals of quartz and coesite.The diffusion pathways,activation energies(Ea),and frequency factors of helium under ambient and high pressure conditions were calculated using Density Functional Theory(DFT)and the climbing image nudged elastic band(CI-NEB)method.The calculated diffusive coefficients of He in the quartz in different orientations are:D[100]=1.24×10^(−6)exp.(−26.83 kJ/mol/RT)m^(2)/s D[010]=1.11×10^(−6)exp.(−31.60 kJ/mol/RT)m^(2)/s.and in the coesite:D[100]=3.00×10^(−7)exp.(−33.79 kJ/mol/RT)m^(2)/s D[001]=2.21×10^(−6)exp.(−18.33 kJ/mol/RT)m^(2)/s.The calculated results indicate that diffusivity of helium is anisotropic in both quartz and coesite and that the degree of anisotropy is much more pronounced in coesite.Helium diffusion behavior in coesite under high pressures was investigated.The activation energies increased with pressure:Ea[100]increased from 33.79 kJ/mol to 58.36 kJ/mol,and Ea[001]increased from 18.33 kJ/mol to 48.87 kJ/mol as pressure increased from0 GPa to 12 GPa.Our calculations showed that helium is not be quantitatively retained in silica at typical surface temperatures on Earth,which is consistent with the findings from previous studies.These results have implications for discussion of the Earth's mantle evolution and for recognition thermal histories of ultra-high pressure(UHP)metamorphic terranes.

Nonlinear Flow Properties of Newtonian Fluids through Rough Crossed Fractures

The nonlinear flow properties of Newtonian fluids through crossed fractures are estimated by considering the influences of length,aperture,and surface roughness of fractures.A total of 252 computational runs are performed by creating 36 computational domains,in which the Navier-Stokes equations are solved.The results show that the nonlinear relationship between flow rate and hydraulic gradient follows Forchheimer’s law–based equation.When the hydraulic gradient is small(i.e.,10^(−6)),the streamlines are parallel to the fracture walls,indicating a linear streamline distribution.When the hydraulic gradient is large(i.e.,10^(0)),the streamlines are disturbed by a certain number of eddies,indicating a nonlinear streamline distribution.The patterns of eddy distributions depend on the length,aperture,and surface roughness of fractures.With the increment of hydraulic gradient from 10^(−6) to 10^(0),the ratio of flow rate to hydraulic gradient holds constants and then decreases slightly and finally decreases robustly.The fluid flow experiences a linear flow regime,a weakly nonlinear regime,and a strongly nonlinear regime,respectively.The critical hydraulic gradient ranges from 3.27×10^(−5) to 5.82×10^(−2) when fracture length=20–100mmandmechanical aperture=1–5mm.The joint roughness coefficient plays a negligible role in the variations in critical hydraulic gradient compared with fracture length and/or mechanical aperture.The critical hydraulic gradient decreases with increasing mechanical aperture,following power-law relationships.The parameters in the functions are associated with fracture length.

Icaritin inhibits the progression of urothelial cancer by suppressing PADI2-mediated neutrophil infiltration and neutrophil extracellular trap formation

Tumor relapse and metastasis are the major causes of mortality associated with urothelial cancer.In the tumor microenvironment,negative regulatory molecules and various immune cell subtypes suppress antitumor immunity.The inflammatory microenvironment,associated with neutrophils and neutrophil extracellular traps(NETs),promotes tumor metastasis.However,no drugs are currently available to specifically inhibit neutrophils and NETs.In this study,we first demonstrated that icaritin(ICT),a Chinese herbal remedy that is a first-line treatment for advanced and incurable hepatocellular carcinoma,reduces NETs caused by suicidal NETosis and prevents neutrophil infiltration in the tumor microenvironment.Mechanistically,ICT binds to and inhibits the expression of PADI2 in neutrophils,thereby suppressing PADI2-mediated histone citrullination.Moreover,ICT inhibits ROS generation,suppresses the MAPK signaling pathway,and inhibits NET-induced tumor metastasis.Simultaneously,ICT inhibits tumoral PADI2-mediated histone citrullination,which consequently suppresses the transcription of neutrophil-recruiting genes such as GM-CSF and IL-6.The downregulation of IL-6 expression,in turn,forms a regulatory feedback loop through the JAK2/STAT3/IL-6 axis.Through a retrospective study of clinical samples,we found a correlation between neutrophils,NETs,UCa prognosis,and immune evasion.Combining ICT with immune checkpoint inhibitors may have synergistic effects.In summary,our study demonstrated that ICT could be a novel inhibitor of NETs and a novel UCa treatment.

Prevalence and Severity of HBV-Associated Acute-on-Chronic Liver Failure Due to Irregular Medication of Nucleos(t)ide Analogs

Hepatitis B virus(HBV)represents the commonest etiologic agent of acute-on-chronic liver failure(ACLF)in most Asian countries.Nucleos(t)ide analogs(NAs)are effective in the treatment of chronic HBV infections,but may also exacerbate the disease and stimulate its development into HBV-associated ACLF if not used appropriately.The current study aimed to assess the prevalence and severity of HBV-associated ACLF as a result from irregular medication of NAs(IMNA).A total of 1134 individuals with HBV-associated ACLF in nine hospitals in Heilongjiang Province were enrolled in this study between 2005 and 2015.Among these,777 chronic hepatitis B(CHB)and 357 HBV-associated liver cirrhosis cases were classified based on various predisposing factors,including IMNA,HBV reactivation(HBVR),infections,treatment drugs,alcohol use and others(hepatitis C virus,hepatitis E virus,gastrointestinal bleeding and unknown reasons).The percentage and improvement rate were examined.Among individuals with HBV-associated ACLF and CHB,IMNA was found in 9.01%,HBVR in 46.20%,infections in 9.52%,treatment drugs in 14.67%,alcohol in 11.71%,and others in 24.58%as predisposing factors.Improvement rates in cases with IMNA,HBVR,infections,treatment drugs,alcohol and others were 41.43%,58.50%,58.11%,56.14%,53.85%,and 65.97%,respectively.Multivariable analysis showed that IMNA,others,infections,hepatic encephalopathy and hepatorenal syndrome were associated with prognosis.Only IMNA independently predicted HBV-associated ACLF prognosis.Overall,our study demonstrated that the percentage of IMNAinduced HBV-associated ACLF was 12.61%,and worse disease conditions resulted from IMNA compared with other factors.Thus,the suitability of treatment with NAs should be thoroughly evaluated.

Estimates of strength and cracking behaviors of pre-flawed granite specimens treated by chemical corrosion under triaxial compression tests

Four types of granite specimens were prepared and treated by chemical corrosion for 5 and 30 days,which were then used to carry out triaxial compression tests under different confining pressuresσ_(3).Type A is the intact sample with no preexisting flaws.Types B and C are the samples containing two relatively low-dip flaws and two relatively high-dip flaws,respectively.Type D is the sample including both relatively low-dip and relatively high-dip flaws.The influences of pH value of chemical solutions,flaw distribution,corrosion time andσ_(3) on triaxial stress-strain curves and ultimate failure modes are analyzed and discussed.The results show that the pH value of the chemical solution,corrosion time and the arrangement of preexisting flaws play crucial roles in the cracking behaviors of granite specimens.Type A specimens have the largest peak axial deviatoric stress,followed by Type C,Type D,and Type B specimens,respectively.It is because the decrease in the inclination of preexisting flaws induces the weakening effect due to the decrease in the shadow area along the compaction direction.Under aσ_(3) of 5 MPa,the peak axial deviatoric stress drops by approximately 40.89%,29.08%,4.08%,and 23.53%for pH=2,4,7,and 12,respectively.For intact granite(Type A)specimens,the ultimate failure mode displays a typical shear mode.The connection of two secondary cracks initiated at the tips of preexisting cracks is always the ultimate failure and crack coalescence mode for Type B specimens.The ultimate failure and crack coalescence mode of Types C and D specimens are significantly affected by pH value of the chemical solution,corrosion time andσ_(3),which is different from those of Types A and B specimens due to the differences in flow distributions.

Empirical prediction of hydraulic aperture of 2D rough fractures:a systematic numerical study

This study aims to propose an empirical prediction model of hydraulic aperture of 2D rough fractures through numerical simulations by considering the influences of fracture length,average mechanical aperture,minimum mechanical aperture,joint roughness coefficient(JRC)and hydraulic gradient.We generate 600 numerical models using successive random additions(SRA)algorithm and for each model,seven hydraulic gradients spanning from 2.5×10^(-7)to 1 are considered to fully cover both linear and nonlinear flow regimes.As a result,a total of 4200 fluid flow cases are simulated,which can provide sufficient data for the prediction of hydraulic aperture.The results show that as the ratio of average mechanical aperture to fracture length increases from 0.01 to 0.2,the hydraulic aperture increases following logarithm functions.As the hydraulic gradient increases from 2.5×10^(-7)to 1,the hydraulic aperture decreases following logarithm functions.When a relatively low hydraulic gradient(i.e.,5×10^(-7))is applied between the inlet and the outlet boundaries,the streamlines are of parallel distribution within the fractures.However,when a relatively large hydraulic gradient(i.e.,0.5)is applied between the inlet and the outlet boundaries,the streamlines are disturbed and a number of eddies are formed.The hydraulic aperture predicted using the proposed empirical functions agree well with the calculated results and is more reliable than those available in the preceding literature.In practice,the hydraulic aperture can be calculated as a first-order estimation using the proposed prediction model when the associated parameters are given.