Identifying geohazards such as landslides and methane leakage is crucial during gas extraction from natural gas hydrate(NGH)reservoirs,and understanding reservoir settlement behavior is central to this assessment.Hori...Identifying geohazards such as landslides and methane leakage is crucial during gas extraction from natural gas hydrate(NGH)reservoirs,and understanding reservoir settlement behavior is central to this assessment.Horizontal wells can enlarge the pressure relief zone within the formation,improving single-well productivity,and are therefore considered a promising approach for NGH development.This study examines the settlement response of hydrate-bearing sediments during depressurization using horizontal wells.A fully coupled thermal,hydraulic,mechanical,and chemical(THMC)model with representative reservoir properties(Shenhu region in the South China Sea)is presented accordingly.The simulations show that lower production pressures,while increasing gas output,also intensify formation settlement.The maximum difference in settlement between the lowest and highest production pressures reaches 0.016 m,contributing to more pronounced differential subsidence.Optimal well placement,specifically targeting a low-saturation hydrate zone containing free gas and situated adjacent to a high-saturation hydrate layer,markedly improves both gas production rate and cumulative yield,while reducing overall settlement and limiting changes in effective stress.展开更多
The Dongsha area,a key target for gas hydrate exploration,is influenced by multiple factors,including sedimentary processes and the paleoenvironment,which play critical roles in gas hydrate formation.To elucidate the ...The Dongsha area,a key target for gas hydrate exploration,is influenced by multiple factors,including sedimentary processes and the paleoenvironment,which play critical roles in gas hydrate formation.To elucidate the coupling among sedimentary processes,paleoenvironment,and gas hydrate accumulation,this study investigates the Site DS-W16 using particle size analysis,biological component content,and geochemistry data.Oxygen isotope data from foraminifera and biostratigraphic evidence indicate that sedimentation at the bottom of core interval from Site DS-W16 began during MIS 11(Marine isotope stage).The sedimentation dynamics of the studied layers are complex,involving gravity flows,traction currents,and suspended deposition.Organic matter shows a significant correlation with transgressive-regressive cycle.The site DS-W16 contains two distinct gas hydrate reservoirs:a shallow reservoir(10-24 mbsf)and a deep reservoir(below 182 mbsf).The paleomarine environment influences gas hydrate accumulation by altering sedimentary processes and sediment characteristics,especially the distribution of biological components.Both shallow and deep gas hydrate reservoirs formed under dynamic conditions dominated by traction currents and are characterized by a higher abundance of foraminifera.Sedimentary layers rich in foraminifera and modified by traction currents represent key intervals for preferential gas hydrate accumulation.展开更多
The development of substitutable meniscus implants that can effectively protect articular cartilage remains a great challenge.Herein,a polyurethane with chemical crosslinking and sulfobetaine extenders containing hydr...The development of substitutable meniscus implants that can effectively protect articular cartilage remains a great challenge.Herein,a polyurethane with chemical crosslinking and sulfobetaine extenders containing hydrophobic chains(PU-CL-hSB)is developed,which could improve comprehensive properties and long-term stability simultaneously.By regulating the mole ratio of functional groups,PU-CL-hSB with appropriate mechanical properties,excellent tribological properties,and good fatigue resistance is used to prepare substitutable meniscus implant by hot-pressing.Due to the synergistic effect of functional groups,PU-CL-hSB meniscus implant presents comparable or even superior properties to native meniscus.It withstands a maximum force of 26.08 N versus 25.14 N for native meniscus,an energy dissipation from 45.93 to 39.17 N mm compared to 28.83 to 19.11 N mm for native meniscus over 300 cycles,and a friction coefficient from 0.08 to 0.19 compared to 0.11 to 0.26 for native meniscus.This PU-CL-hSB meniscus implant is further implanted into live rabbit knee joints for 8 and 25 weeks by a new approach,and in vivo data indicate that PU-CL-hSB meniscus implant not only protects articular cartilage from severe damage without eliciting inflammatory responses,but also can maintain normal physiological activities in the native state.Our findings present a substitutable meniscus implant that could be applied in vivo and propose evaluation methodologies for meniscus implants.展开更多
Ultra-high molecular weight polyethylene(UHMWPE)is a key material for marine applications owing to its outstanding self-lubrication and corrosion resistance.However,its long-term performance is compromised by plastic ...Ultra-high molecular weight polyethylene(UHMWPE)is a key material for marine applications owing to its outstanding self-lubrication and corrosion resistance.However,its long-term performance is compromised by plastic deformation in seawater.In this study,we performed a comparative analysis of the UHMWPE dynamics under seawater and water conditions to investigate the plastic deformation of UHMWPE induced by seawater.The results show that the plastic deformation of UHMWPE is amplified in seawater relative to the water conditions.Under thin fluid conditions,frictional interfaces exhibit a higher interfacial friction force and interaction energy in seawater than in water.Compared to freely diffused water molecules,hydrated ions occupy larger interchain spaces within polyethylene.Furthermore,the diffusion of hydrated ions weakens the interchain interactions,promoting more severe polyethylene chain rearrangement and accelerating seawater-induced plastic deformation in UHMWPE during friction.Furthermore,the diffused seawater accelerated the disentangling of the polyethylene chains and enhanced the orderly orientation distribution of polyethylene.Compared to free water molecules,the water molecules of hydrated ions exhibit enhanced attraction to free-flowing water molecules,thereby accelerating seawater flow across submerged UHMWPE surfaces.This flow enhancement promotes surface polyethylene chain mobility in seawater.展开更多
Perovskites exhibit excellent protonic conductivity in the mid-temperature range,and among them,yttria-doped barium zirconate(BZY)is considered one of the most promising perovskite proton conductors.Molecular simulati...Perovskites exhibit excellent protonic conductivity in the mid-temperature range,and among them,yttria-doped barium zirconate(BZY)is considered one of the most promising perovskite proton conductors.Molecular simulations provide an efficient approach to investigating the thermal transport behavior of nanocrystalline materials.The effect of doping concentration on the thermal transport properties of BZY structures was investigated using the equilibrium molecular dynamics(EMD)method combined with phonon spectral energy density(SED)analysis.The results show that the thermal transport properties gradually decrease with increasing doping concentration,and for structures with dopants only and without oxygen vacancies,the thermal conductivity exhibits a similar decreasing trend but remains higher than that of structures containing both dopants and oxygen vacancies.Comparison of phonon lifetime and group velocity reveals that oxygen vacancy defects enhance phonon scattering,thereby leading to a reduction in thermal transport properties,while doping reduces the thermal transport properties by weakening lattice harmonicity.The effect of different hydration levels on the thermal transport properties of BZY was also investigated,and the results indicate that the thermal conductivity fluctuates in structures with low hydration levels and continues to decrease as the proton defect concentration increases with hydration.Further analysis of phonon lifetime and group velocity demonstrates that proton defects reduce the thermal transport properties through both enhanced phonon diffusion and weakened harmonicity.展开更多
This article presents findings from an extensive experimental program conducted by the French Agency for the Management of Radioactive Waste(ANDRA)at its Underground Research Laboratory.The focus of the study is the N...This article presents findings from an extensive experimental program conducted by the French Agency for the Management of Radioactive Waste(ANDRA)at its Underground Research Laboratory.The focus of the study is the NSC(Noyau de SCellement)experiment,designed to assess the performance of a sealing core composed of a mixture of 40%bentonite and 60%sand.The objective is to evaluate in situ hydraulic permeability,swelling behavior,and gas performance of the seal,which are essential components for the safe disposal of Intermediate-Level(IL)and High-Level Radioactive Waste(HLW)in deep geological repositories.The experimental setup,construction details of the NSC experiment,and the timeline of the project,from excavation,construction of the seal,and artificial hydration to hydraulic permeability tests,are comprehensively described.Andra has acquired valuable expertise in constructing an engineered barrier system,encompassing concrete plugs,and efficiently assembling a 5-m-long seal.Over the past decade,a controlled water injection process has been employed to hydrate the seal.The operational efficiency of sensors has been evaluated,with pore pressure sensors exhibiting moderate performance.In contrast,others,including total pressure,capacitive humidity,psychrometric humidity,and saturation sensors,demonstrate excellent performance up to their operational limits.The high-quality data obtained from this experiment will facilitate the modeling of the resaturation and hydraulic-gas performance of the seal.展开更多
A green pregelatinized glutinous rice flour biological admixture was developed in this paper.The cement hydration process,hydration products,pore structure,and strength of mortar with different quantities of glutinous...A green pregelatinized glutinous rice flour biological admixture was developed in this paper.The cement hydration process,hydration products,pore structure,and strength of mortar with different quantities of glutinous rice flour(GRF),and the macroscopic changes in concrete cracking resistance testing were investigated.Simultaneously,a fast cracking resistance evaluation method based on graphic recognition was proposed.The results indicated that pregelatinized glutinous rice flour(T-GRF)delayed the dissolution rate of anhydrous cement during the induction period,shifting the main exothermic peak of hydration backward.The compressive strength developed slowly in 7-28 d age and returned to normal in 28-56 d.The compressive strength of T-GRF-0.6% modified mortar at 56 d age is less than 10% different from that of control group.The 3.0%T-GRF decreased the total porosity by 3%,and the average pore size decreased from 31.2 to 21.3 nm measured by MIP,indicating that T-GRF could inhibit harmful pores and densify concrete.The crack resistance coefficient of T-GRF modified concrete was obtained by image recognition method,and the GRF could decrease the length,width,and damaged area of cracks in the early age of concrete.展开更多
Solar-driven interfacial desalination(SID)offers a sustainable route for freshwater production,yet its long-term performance is compromised by salt crystallization and microbial fouling under complex marine conditions...Solar-driven interfacial desalination(SID)offers a sustainable route for freshwater production,yet its long-term performance is compromised by salt crystallization and microbial fouling under complex marine conditions.Zwitterionic polymers offer promising nonfouling capabilities,but current zwitterionic hydrogel-based solar evaporators(HSEs)suffer from inadequate hydration and salt vulnerability.Inspired by the natural marine environmental adaptive characteristics of saltwater fish,we report a superhydrated zwitterionic poly(trimethylamine N-oxide,PTMAO)/polyacrylamide(PAAm)/polypyrrole(PPy)hydrogel(PTAP)with dedicated water channels for efficient,durable,and nonfouling SID.The directly linked N⁺and O⁻groups in PTMAO establish a robust hydration shell that facilitates rapid water transport while resisting salt and microbial adhesion.Integrated PAAm and PPy networks enhance mechanical strength and photothermal conversion.PTAP achieves a high evaporation rate of 2.35 kg m^(−2)h^(−1)under 1 kW m^(–2)in 10 wt%NaCl solution,maintaining stable operation over 100 h without salt accumulation.Furthermore,PTAP effectively resists various foulants including proteins,bacterial,and algal adhesion.Molecular dynamics simulations reveal that the exceptional hydration capacity supports its nonfouling properties.This work advances the development of nonfouling HSEs for sustainable solar desalination in real-world marine environments.展开更多
To address the challenge of balancing thermal management and thermal runaway mitigation,it is crucial to explore effective methods for enhancing the safety of lithium-ion battery systems.Herein,an innovative hydrated ...To address the challenge of balancing thermal management and thermal runaway mitigation,it is crucial to explore effective methods for enhancing the safety of lithium-ion battery systems.Herein,an innovative hydrated salt composite phase change material(HSCPCM)with dual phase transition temperature zones has been proposed.This HSCPCM,denoted as SDMA10,combines hydrophilic modified expanded graphite,an acrylic emulsion coating,and eutectic hydrated salts to achieve leakage prevention,enhanced thermal stability,cycling stability,and superior phase change behavior.Battery modules incorporating SDMA10 demonstrate significant thermal control capabilities.Specifically,the cylindrical battery modules with SDMA10 can maintain maximum operating temperatures below 55°C at 4 C discharge rate,while prismatic battery modules can keep maximum operating temperatures below 65°C at 2 C discharge rate.In extreme battery overheating conditions simulated using heating plates,SDMA10 effectively suppresses thermal propagation.Even when the central heating plate reaches 300°C,the maximum temperature at the module edge heating plates remains below 85°C.Further,compared to organic composite phase change materials(CPCMs),the battery module with SDMA10 can further reduce the peak thermal runaway temperature by 93°C and delay the thermal runaway trigger time by 689 s,thereby significantly decreasing heat diffusion.Therefore,the designed HSCPCM integrates excellent latent heat storage and thermochemical storage capabilities,providing high thermal energy storage density within the thermal management and thermal runaway threshold temperature range.This research will offer a promising pathway for improving the thermal safety performance of battery packs in electric vehicles and other energy storage systems.展开更多
In coal mining on a high-pressure Ordovician limestone aquifer,grouting materials should have sufficient mechanical properties,particularly strong interfacial bonding performance to address stress concentration at the...In coal mining on a high-pressure Ordovician limestone aquifer,grouting materials should have sufficient mechanical properties,particularly strong interfacial bonding performance to address stress concentration at the grout-limestone interface induced by rock stress disturbances during mining.In this study,graphene oxide(GO)was integrated into cement-polyacrylate composite grout to improve its interfacial bonding.First,four-point bending tests were conducted,and the Monte Carlo method combined with the simplex search algorithm was employed to determine the variations in shear cohesion and static friction parameters.The results reveal that GO can significantly increase both the tensile and shear cohesion of the grout-limestone interface,but minimally affects the interfacial friction coefficient.Second,nuclear magnetic resonance(NMR)and scanning electron microscopy(SEM)tests were performed.The results indicate that GO nanosheets result in a squamaceous microstructure of the grout consolidation mass,increasing the adhesion of the grout-limestone interface.Moreover,spiny Aft(ettringite)clusters can be induced in limestone fracture surfaces by GO,which could serve as anchors for limestone and grout consolidation mass.展开更多
Zn-based thermal charging devices,utilizing the synergistic effect of ion thermoextraction and thermodiffusion,are able to efficiently convert thermal energy into electrical energy and storage in the devices,making th...Zn-based thermal charging devices,utilizing the synergistic effect of ion thermoextraction and thermodiffusion,are able to efficiently convert thermal energy into electrical energy and storage in the devices,making them a highly promising technology for low-grade heat recovery and utilization.However,the low output power density and energy conversion efficiency resulted by the slow diffusion kinetics of Zn^(2+)hinder their development.Herein,we present a highperformance thermal charging cell design using Zn^(2+)/NH_(4)^(+)hybrid ion electrolyte,which not only maintains the high output voltage of the Zn-based thermoelectric system,but also significantly enhances the output power density due to the fast diffusion kinetics of NH_(4)^(+).Based on this strategy,the thermal charging cell displays a high thermopower of 12.5 mV K^(-1)and an excellent normalized power density of 19.6 mW m^(-2)K^(-2)at a temperature difference of 35 K.The Carnot-relative efficiency is as high as 12.74%.Moreover,it can operate continuously for over 72 h when the temperature difference persists,achieving a balance between thermoelectric conversion and output.This work provides a simple and effective strategy for the design of high-performance thermal charging cells for low-grade heat conversion and utilization.展开更多
In the steel slag-based mine backfill cementitious material systems,the hydration reaction mechanisms and synergistic effects of steel slag(SS),granulated blast furnace slag(GBFS),and desulfurization gypsum(DG)are cru...In the steel slag-based mine backfill cementitious material systems,the hydration reaction mechanisms and synergistic effects of steel slag(SS),granulated blast furnace slag(GBFS),and desulfurization gypsum(DG)are crucial for performance optimization and regulation.However,existing studies have yet to fully reveal the underlying synergistic mechanisms,which limits the application and promotion of high SS content in mine backfill and low-carbon building materials.This study systematically explores the synergistic effects between various solid wastes and their regulation of the hydration process in the SS-based cementitious system through multi-scale characterization techniques.The results show that GBFS,by releasing active Si^(4+)and Al^(3+),triggers a synergistic activation effect with Ca^(2+)provided by SS,promoting the formation of C-S-H gel and ettringite,significantly optimizing the hardened paste microstructure.When the GBFS content reaches 30%,the C-S-H content increases by 40.8%,the pore size distribution improves,the proportion of large pores decreases by 68.7%,and the 90-day compressive strength increases to 5 times that of the baseline group.The sulfate activation effect of DG accelerates the hydration of silicate minerals,but excessive incorporation(>16%)can lead to microcracks caused by the expansion of AFt crystals,resulting in a strength reduction.Under the synergistic effect of 8%DG and 30%GBFS,the hydration reaction is most intense,with the peak heat release rate reaching 0.92 mW/g and the cumulative heat release amount being 240 J/g.By constructing a“SS-GBFS-DG-cement”quaternary synergistic system(mass ratio range:SS:GBFS:cement:DG=(50–62):(20–40):10:(8–12)),the matching of active components in high-content SS systems was optimized,significantly improving microstructural defects and meeting engineering application requirements.This study provides a theoretical basis for the component design and performance regulation of high-content SS-based cementitious materials.展开更多
Natural gas hydrates widely accumulate in submarine sediments composed of clay minerals.However,due to the complex physiochemistry and micron-sized particles of clay minerals,their effects on methane hydrate(MH)format...Natural gas hydrates widely accumulate in submarine sediments composed of clay minerals.However,due to the complex physiochemistry and micron-sized particles of clay minerals,their effects on methane hydrate(MH)formation and dissociation are still in controversy.In this study,montmorillonite and illite were separately mixed with quartz sand to investigate their effects on MH formation and dissociation.The microstructure of synthesized samples was observed by cryo-SEM innovatively to understand the effects of montmorillonite and illite on MH phase transition in micron scale.Results show that montmorillonite and illite both show the inhibition on MH formation kinetics and water-to-hydrate conversion,and illite shows a stronger inhibition.The 10 wt%montmorillonite addition significantly retards MH formation rate,and the 20 wt%montmorillonite has a less inhibition on the rate.The increase of illite mass ratio(0-20 wt%)retards the rate of MH formation.As the content of clay minerals increase,the water-to-hydrate conversion decreases.Cryo-SEM images presented that montmorillonite aggregates separate as individual clusters while illite particles pack as face-to-face configuration under the interaction with water.The surface-overlapped illite aggregates would make sediments pack tightly,hinder the contact between gas and water,and result in the more significant inhibition on MH formation kinetics.Under the depressurization method,the addition of clay minerals facilitates MH dissociation rate.Physicochemical properties of clay minerals and MH distribution in the pore space lead to the faster dissociation rate in clay-containing sediments.The results of this study would provide beneficial guides on geological investigations and optimizing strategies of natural gas production in marine hydrate-bearing sediments.展开更多
This study presents a novel approach to improving the anticorrosive performance of AZ31 Mg alloy by exploiting the role of the hydration reaction to induce interactions between Quinolin-8-ol(8HQ)molecules and the poro...This study presents a novel approach to improving the anticorrosive performance of AZ31 Mg alloy by exploiting the role of the hydration reaction to induce interactions between Quinolin-8-ol(8HQ)molecules and the porous MgO layer formed via plasma electrolytic oxidation(PEO).The AZ31 Mg alloy,initially coated with a PEO layer,underwent a dipping treatment in an ethanolic solution of 0.05 M 8HQ at 50℃ for 3 h.The results were compared with those from a different procedure where the PEO layer was subjected to a hydration reaction for 2 h at 90℃ before immersion in the 8HQ solution under the same conditions.The hydration treatment played a crucial role by converting MgO to Mg(OH)_(2),significantly enhancing the surface reactivity.This transformation introduced hydroxyl groups(−OH)on the surface,which facilitated donor-acceptor interactions with the electron-accepting sites on 8HQ molecules.The calculated binding energy(Ebinding)from DFT indicated that the interaction energy of 8HQ with Mg(OH)_(2) was lower compared to 8HQ with MgO,suggesting easier adsorption of 8HQ molecules on the hydrated surface.This,combined with the increased number of active sites and enhanced surface area,allowed for extensive surface coverage by 8HQ,leading to the formation of a stable,flake-like protective layer that sealed the majority of pores on the PEO layer.DFT calculations further suggested that the hydration treatment provided multiple active sites,enabling effective contact with 8HQ and rapid electron transfer,creating ideal conditions for charge-transfer-induced physical and chemical bonding.This study shows that hydration and 8HQ treatments significantly enhance the corrosion resistance of Mg alloys,highlighting their potential for advanced anticorrosive coatings.展开更多
The mechanism of hydrate-based desalination is that water molecules would transfer to the hydrate phase during gas hydrate formation process,while the salt ions would be conversely concentrated in the unreacted saltwa...The mechanism of hydrate-based desalination is that water molecules would transfer to the hydrate phase during gas hydrate formation process,while the salt ions would be conversely concentrated in the unreacted saltwater.However,the salt concentration of hydrate decomposed water and the desalination degree of hydrate phase are still unclear.The biggest challenge is how to effectively separate the hydrate phase and the remaining unreacted salt water,and then decompose the hydrate phase to measure the salt concentration of hydrate melt water.This work developed an apparatus and pressure-driven filtration method to efficiently separate the hydrate phase and the remaining unreacted saltwater.On this basis,the single hydrate phase was obtained,then it was dissociated and the salt concentration of hydrate melt water was measured.The experimental results demonstrate that when the initial salt mass concentration is 0.3% to 8.0%,the salt removal efficiency for NaCl solution is 15.9% to 29.8%by forming CO_(2) hydrate,while for CaCl_(2) solution is 28.9%to 45.5%.The solute CaCl_(2) is easier to be removed than solute NaCl.In addition,the salt removal efficiency for forming CO_(2) hydrate is higher than that for forming methane hydrate.The multi-stage desalination can continuously decrease the salt concentration of hydrate dissociated water,and the salt removal efficiency per stage is around 20%.展开更多
Using cemented rockfill to replace coal pillars offers an effective solution for reducing solid waste while ensuring the safety of gob-side entries.However,achieving the balance among low cost,high waste recycling rat...Using cemented rockfill to replace coal pillars offers an effective solution for reducing solid waste while ensuring the safety of gob-side entries.However,achieving the balance among low cost,high waste recycling rates,and adequate strength remains a significant challenge for cemented rockfill.This study used a composite alkali activator to activate gangue cemented rockfill.The compressive strength,scanning electron microscopy,energy dispersive spectrometer,mercury intrusion porosimetry,X-ray diffraction,and thermogra-vimetric tests were carried out to investigate the effect of the composite alkali activator proportion on the compressive strength,micro-structure,and composition of the cemented rockfill.The calcium silicate hydrate(C–S–H)molecular model of cemented rockfill was con-structed to explore the fracture evolution of the nucleated molecular structure under tension.The results show that compressive strength initially increased and then decreased with the activator proportion,the optimal activator proportion of 1:2 resulted in a 31.25%increase in strength at 3 d.This reasonable activator proportion strengthens the pozzolanic effect of gangue,and consumes more calcium hydroxide to inhibit its agglomeration,ultimately achieving the densification of microstructure.The activator proportion inevitably substitutes calcium ions with sodium ions in the C–S–H molecular model.The 12%substitution of calcium ions increases the adhesion between silicon chain layers,which is beneficial to the interlayer stress transfer.This work proposes a method for preparing low-cost cemented rockfill from al-kali-activated gangue,which can be used for solid waste recycling and reducing cement consumption to achieve low-carbon goals.展开更多
Natural gas hydrates(hereinafter referred to as hydrates)are a promising clean energy source.However,their current development is far from reaching commercial exploitation.Reservoir stimulation tech-nology provides ne...Natural gas hydrates(hereinafter referred to as hydrates)are a promising clean energy source.However,their current development is far from reaching commercial exploitation.Reservoir stimulation tech-nology provides new approaches to enhance hydrate development effectiveness.Addressing the current lack of quantitative and objective methods for evaluating the fracability of hydrate reservoirs,this study clarifies the relationship between geological and engineering fracability and proposes a comprehensive evaluation model for hydrate reservoir fracability based on grey relational analysis and the criteria importance through intercriteria correlation method.By integrating results from hydraulic fracturing experiments on hydrate sediments,the fracability of hydrate reservoirs is assessed.The concept of critical construction parameter curves for hydrate reservoirs is introduced for the first time.Additionally,two-dimensional fracability index evaluation charts and three-dimensional fracability construction condition discrimination charts are established.The results indicate that as the comprehensive fracability index increases,the feasibility of forming fractures in hydrate reservoirs improves,and the required normalized fracturing construction parameters gradually decrease.The accuracy rate of the charts in judging experimental results reached 89.74%,enabling quick evaluations of whether hydrate reservoirs are worth fracturing,easy to fracture,and capable of being fractured.This has significant engineering implications forthehydraulicfracturingof hydratereservoirs.展开更多
Morphology and growth rate of carbon dioxide hydrate on the interface between liquid carbon dioxide and humic acid solutions were studied in this work.It was found that after the growth of the hydrate film at the inte...Morphology and growth rate of carbon dioxide hydrate on the interface between liquid carbon dioxide and humic acid solutions were studied in this work.It was found that after the growth of the hydrate film at the interface,further growth of hydrate due to the suction of water in the capillary system formed between the wall of the cuvette and the end boundary of the hydrate layer occurs.Most probably,substantial effects on the formation of this capillary system may be caused by variations in reactor wall properties,for example,hydrophobic-hydrophilic balance,roughness,etc.We found,that the rate of CO_(2) hydrate film growth on the surface of the humic acid aqueous solution is 4-fold to lower in comparison with the growth rate on the surface of pure water.We suppose that this is caused by the adsorption of humic acid associates on the surface of hydrate particles and,as a consequence,by the deceleration of the diffusion of dissolved carbon dioxide to the growing hydrate particle.展开更多
This study proposes and systematically evaluates an optimized integration of warm surface seawater injection with depressurization for the long-term exploitation of marine natural gas hydrates.By employing comprehensi...This study proposes and systematically evaluates an optimized integration of warm surface seawater injection with depressurization for the long-term exploitation of marine natural gas hydrates.By employing comprehensive multiphysics simulations guided by field data from hydrate production tests in the South China Sea,we pinpoint key operational parameters—such as injection rates,depths,and timings—that notably enhance production efficiency.The results indicate that a 3-phase hydrate reservoir transitions from a free-gas-dominated production stage to a hydrate-decomposition-dominated stage.Moderate warm seawater injection supplies additional heat during the hydrate decomposition phase,thereby enhancing stable production;however,excessively high injection rates can impede the depressurization process.Only injection at an appropriate depth simultaneously balances thermal supplementation and the pressure gradient,leading to higher overall productivity.A“depressurization-driven sensible-heat supply window”is introduced,highlighting that timely seawater injection following initial depressurization prolongs reservoir dissociation dynamics.In this study area,commencing seawater injection at 170 d of depressurization proved optimal.This optimized integration leverages clean and renewable thermal energy,providing essential insights into thermal supplementation strategies with significant implications for sustainable,economically feasible,and efficient commercial-scale hydrate production.展开更多
Carbon dioxide(CO_(2))marine sequestration by hydrate method is considered as one of the options to effectively achieve carbon reduction.However,the slow rate of hydrate formation becomes a major limiting factor.In vi...Carbon dioxide(CO_(2))marine sequestration by hydrate method is considered as one of the options to effectively achieve carbon reduction.However,the slow rate of hydrate formation becomes a major limiting factor.In view of the gas-water mass transfer problem which is the main obstacle,this paper explored the amphiphilic amino acids to promote the formation of CO_(2)hydrate and used low-field nuclear magnetic resonance(LNMR)to conduct an innovative study on its kinetics and spatiotemporal distribution.By comparing the promotion performance of L-methionine(L-met),L-cysteine(L-cys),and L-valine(L-val),the comprehensive kinetic promotion ability of L-met was the highest,reducing the induction time by 60.0%,achieving the maximum water conversion of about 57.0%within only 1 h,and reaching a final CO_(2)storage efficiency of 84.6%.LNMR results showed that hydrates were preferentially formed in large and medium pores in the reservoir region.Interestingly,we found that the combined effect of hydrophilic groups and the hydrophobic side chain of L-met not only promoted the rearrangement of water molecules and provided more nucleation sites,but also created a localized CO_(2)supersaturated environment and facilitated gas-water redistribution.Meanwhile,L-met promoted the formation of a hydrate porous structure to ensure the continuous formation of hydrates.This study innovatively explored CO_(2)hydrate formation behavior in amphiphilic amino acids and laid a theoretical foundation for the realization of CO_(2)marine sequestration by hydrate method.展开更多
基金supported by the State Key Research Development Program of China(Grant No.2021YFC2800905-02)the National Natural Science Foundation of China(Grant No.52304208)。
文摘Identifying geohazards such as landslides and methane leakage is crucial during gas extraction from natural gas hydrate(NGH)reservoirs,and understanding reservoir settlement behavior is central to this assessment.Horizontal wells can enlarge the pressure relief zone within the formation,improving single-well productivity,and are therefore considered a promising approach for NGH development.This study examines the settlement response of hydrate-bearing sediments during depressurization using horizontal wells.A fully coupled thermal,hydraulic,mechanical,and chemical(THMC)model with representative reservoir properties(Shenhu region in the South China Sea)is presented accordingly.The simulations show that lower production pressures,while increasing gas output,also intensify formation settlement.The maximum difference in settlement between the lowest and highest production pressures reaches 0.016 m,contributing to more pronounced differential subsidence.Optimal well placement,specifically targeting a low-saturation hydrate zone containing free gas and situated adjacent to a high-saturation hydrate layer,markedly improves both gas production rate and cumulative yield,while reducing overall settlement and limiting changes in effective stress.
基金supported by National Natural Science Foundation of China(No.42376217)Fundamental Research Funds for the Central Universities of China(No.3-7-10-2025-03)National Key Research and Development Program of China(No.2024YFC2814702).
文摘The Dongsha area,a key target for gas hydrate exploration,is influenced by multiple factors,including sedimentary processes and the paleoenvironment,which play critical roles in gas hydrate formation.To elucidate the coupling among sedimentary processes,paleoenvironment,and gas hydrate accumulation,this study investigates the Site DS-W16 using particle size analysis,biological component content,and geochemistry data.Oxygen isotope data from foraminifera and biostratigraphic evidence indicate that sedimentation at the bottom of core interval from Site DS-W16 began during MIS 11(Marine isotope stage).The sedimentation dynamics of the studied layers are complex,involving gravity flows,traction currents,and suspended deposition.Organic matter shows a significant correlation with transgressive-regressive cycle.The site DS-W16 contains two distinct gas hydrate reservoirs:a shallow reservoir(10-24 mbsf)and a deep reservoir(below 182 mbsf).The paleomarine environment influences gas hydrate accumulation by altering sedimentary processes and sediment characteristics,especially the distribution of biological components.Both shallow and deep gas hydrate reservoirs formed under dynamic conditions dominated by traction currents and are characterized by a higher abundance of foraminifera.Sedimentary layers rich in foraminifera and modified by traction currents represent key intervals for preferential gas hydrate accumulation.
基金supported by the Special Project for High-tech Industrialization of Science and Technology Cooperation between Jilin Province and Chinese Academy of Sciences(2023SYHZ0042)。
文摘The development of substitutable meniscus implants that can effectively protect articular cartilage remains a great challenge.Herein,a polyurethane with chemical crosslinking and sulfobetaine extenders containing hydrophobic chains(PU-CL-hSB)is developed,which could improve comprehensive properties and long-term stability simultaneously.By regulating the mole ratio of functional groups,PU-CL-hSB with appropriate mechanical properties,excellent tribological properties,and good fatigue resistance is used to prepare substitutable meniscus implant by hot-pressing.Due to the synergistic effect of functional groups,PU-CL-hSB meniscus implant presents comparable or even superior properties to native meniscus.It withstands a maximum force of 26.08 N versus 25.14 N for native meniscus,an energy dissipation from 45.93 to 39.17 N mm compared to 28.83 to 19.11 N mm for native meniscus over 300 cycles,and a friction coefficient from 0.08 to 0.19 compared to 0.11 to 0.26 for native meniscus.This PU-CL-hSB meniscus implant is further implanted into live rabbit knee joints for 8 and 25 weeks by a new approach,and in vivo data indicate that PU-CL-hSB meniscus implant not only protects articular cartilage from severe damage without eliciting inflammatory responses,but also can maintain normal physiological activities in the native state.Our findings present a substitutable meniscus implant that could be applied in vivo and propose evaluation methodologies for meniscus implants.
基金financially supported by the National Natural Science Foundation of China(Nos.51909023 and 51775077)the Natural Science Foundation of Liaoning Province(No.2021-MS-140)the Fundamental Research Funds for the Central Universities(No.3132025114)。
文摘Ultra-high molecular weight polyethylene(UHMWPE)is a key material for marine applications owing to its outstanding self-lubrication and corrosion resistance.However,its long-term performance is compromised by plastic deformation in seawater.In this study,we performed a comparative analysis of the UHMWPE dynamics under seawater and water conditions to investigate the plastic deformation of UHMWPE induced by seawater.The results show that the plastic deformation of UHMWPE is amplified in seawater relative to the water conditions.Under thin fluid conditions,frictional interfaces exhibit a higher interfacial friction force and interaction energy in seawater than in water.Compared to freely diffused water molecules,hydrated ions occupy larger interchain spaces within polyethylene.Furthermore,the diffusion of hydrated ions weakens the interchain interactions,promoting more severe polyethylene chain rearrangement and accelerating seawater-induced plastic deformation in UHMWPE during friction.Furthermore,the diffused seawater accelerated the disentangling of the polyethylene chains and enhanced the orderly orientation distribution of polyethylene.Compared to free water molecules,the water molecules of hydrated ions exhibit enhanced attraction to free-flowing water molecules,thereby accelerating seawater flow across submerged UHMWPE surfaces.This flow enhancement promotes surface polyethylene chain mobility in seawater.
基金Project supported by the National Natural Science Foundation of China(Grant No.12172112)the National Natural Science Foundation of China(Joint Fund for Corporate Innovation and Development-Key Program)(Grant No.U22B2082)。
文摘Perovskites exhibit excellent protonic conductivity in the mid-temperature range,and among them,yttria-doped barium zirconate(BZY)is considered one of the most promising perovskite proton conductors.Molecular simulations provide an efficient approach to investigating the thermal transport behavior of nanocrystalline materials.The effect of doping concentration on the thermal transport properties of BZY structures was investigated using the equilibrium molecular dynamics(EMD)method combined with phonon spectral energy density(SED)analysis.The results show that the thermal transport properties gradually decrease with increasing doping concentration,and for structures with dopants only and without oxygen vacancies,the thermal conductivity exhibits a similar decreasing trend but remains higher than that of structures containing both dopants and oxygen vacancies.Comparison of phonon lifetime and group velocity reveals that oxygen vacancy defects enhance phonon scattering,thereby leading to a reduction in thermal transport properties,while doping reduces the thermal transport properties by weakening lattice harmonicity.The effect of different hydration levels on the thermal transport properties of BZY was also investigated,and the results indicate that the thermal conductivity fluctuates in structures with low hydration levels and continues to decrease as the proton defect concentration increases with hydration.Further analysis of phonon lifetime and group velocity demonstrates that proton defects reduce the thermal transport properties through both enhanced phonon diffusion and weakened harmonicity.
文摘This article presents findings from an extensive experimental program conducted by the French Agency for the Management of Radioactive Waste(ANDRA)at its Underground Research Laboratory.The focus of the study is the NSC(Noyau de SCellement)experiment,designed to assess the performance of a sealing core composed of a mixture of 40%bentonite and 60%sand.The objective is to evaluate in situ hydraulic permeability,swelling behavior,and gas performance of the seal,which are essential components for the safe disposal of Intermediate-Level(IL)and High-Level Radioactive Waste(HLW)in deep geological repositories.The experimental setup,construction details of the NSC experiment,and the timeline of the project,from excavation,construction of the seal,and artificial hydration to hydraulic permeability tests,are comprehensively described.Andra has acquired valuable expertise in constructing an engineered barrier system,encompassing concrete plugs,and efficiently assembling a 5-m-long seal.Over the past decade,a controlled water injection process has been employed to hydrate the seal.The operational efficiency of sensors has been evaluated,with pore pressure sensors exhibiting moderate performance.In contrast,others,including total pressure,capacitive humidity,psychrometric humidity,and saturation sensors,demonstrate excellent performance up to their operational limits.The high-quality data obtained from this experiment will facilitate the modeling of the resaturation and hydraulic-gas performance of the seal.
基金Funded by Hainan Provincial Natural Science Foundation(No.522QN279)State Key Laboratory of High Performance Civil Engineering Materials(No.2023CEM004)。
文摘A green pregelatinized glutinous rice flour biological admixture was developed in this paper.The cement hydration process,hydration products,pore structure,and strength of mortar with different quantities of glutinous rice flour(GRF),and the macroscopic changes in concrete cracking resistance testing were investigated.Simultaneously,a fast cracking resistance evaluation method based on graphic recognition was proposed.The results indicated that pregelatinized glutinous rice flour(T-GRF)delayed the dissolution rate of anhydrous cement during the induction period,shifting the main exothermic peak of hydration backward.The compressive strength developed slowly in 7-28 d age and returned to normal in 28-56 d.The compressive strength of T-GRF-0.6% modified mortar at 56 d age is less than 10% different from that of control group.The 3.0%T-GRF decreased the total porosity by 3%,and the average pore size decreased from 31.2 to 21.3 nm measured by MIP,indicating that T-GRF could inhibit harmful pores and densify concrete.The crack resistance coefficient of T-GRF modified concrete was obtained by image recognition method,and the GRF could decrease the length,width,and damaged area of cracks in the early age of concrete.
基金supported by National Natural Science Foundation of China(22209036,U23A20119)Hebei Provincial Natural Science Foundation,Excellent Youth Project(E2023202069)+1 种基金National Key R&D Program of China(2024YFF0506000,2024YFB4609100)Fundamental Research Foundation from Hebei University of Technology(424132016,282021485).
文摘Solar-driven interfacial desalination(SID)offers a sustainable route for freshwater production,yet its long-term performance is compromised by salt crystallization and microbial fouling under complex marine conditions.Zwitterionic polymers offer promising nonfouling capabilities,but current zwitterionic hydrogel-based solar evaporators(HSEs)suffer from inadequate hydration and salt vulnerability.Inspired by the natural marine environmental adaptive characteristics of saltwater fish,we report a superhydrated zwitterionic poly(trimethylamine N-oxide,PTMAO)/polyacrylamide(PAAm)/polypyrrole(PPy)hydrogel(PTAP)with dedicated water channels for efficient,durable,and nonfouling SID.The directly linked N⁺and O⁻groups in PTMAO establish a robust hydration shell that facilitates rapid water transport while resisting salt and microbial adhesion.Integrated PAAm and PPy networks enhance mechanical strength and photothermal conversion.PTAP achieves a high evaporation rate of 2.35 kg m^(−2)h^(−1)under 1 kW m^(–2)in 10 wt%NaCl solution,maintaining stable operation over 100 h without salt accumulation.Furthermore,PTAP effectively resists various foulants including proteins,bacterial,and algal adhesion.Molecular dynamics simulations reveal that the exceptional hydration capacity supports its nonfouling properties.This work advances the development of nonfouling HSEs for sustainable solar desalination in real-world marine environments.
基金financially supported by Natural Science Foundation of Guangdong province(2024A1515010228)CATARC Automotive Inspection Center Excellent Engineer Program(2023B0909050007).
文摘To address the challenge of balancing thermal management and thermal runaway mitigation,it is crucial to explore effective methods for enhancing the safety of lithium-ion battery systems.Herein,an innovative hydrated salt composite phase change material(HSCPCM)with dual phase transition temperature zones has been proposed.This HSCPCM,denoted as SDMA10,combines hydrophilic modified expanded graphite,an acrylic emulsion coating,and eutectic hydrated salts to achieve leakage prevention,enhanced thermal stability,cycling stability,and superior phase change behavior.Battery modules incorporating SDMA10 demonstrate significant thermal control capabilities.Specifically,the cylindrical battery modules with SDMA10 can maintain maximum operating temperatures below 55°C at 4 C discharge rate,while prismatic battery modules can keep maximum operating temperatures below 65°C at 2 C discharge rate.In extreme battery overheating conditions simulated using heating plates,SDMA10 effectively suppresses thermal propagation.Even when the central heating plate reaches 300°C,the maximum temperature at the module edge heating plates remains below 85°C.Further,compared to organic composite phase change materials(CPCMs),the battery module with SDMA10 can further reduce the peak thermal runaway temperature by 93°C and delay the thermal runaway trigger time by 689 s,thereby significantly decreasing heat diffusion.Therefore,the designed HSCPCM integrates excellent latent heat storage and thermochemical storage capabilities,providing high thermal energy storage density within the thermal management and thermal runaway threshold temperature range.This research will offer a promising pathway for improving the thermal safety performance of battery packs in electric vehicles and other energy storage systems.
基金supported by the National Key R&D Program of China(Grant Nos.U25A20810 and 2024YFF0508201)the National Natural Science Foundation of China(Grant No.12302504).
文摘In coal mining on a high-pressure Ordovician limestone aquifer,grouting materials should have sufficient mechanical properties,particularly strong interfacial bonding performance to address stress concentration at the grout-limestone interface induced by rock stress disturbances during mining.In this study,graphene oxide(GO)was integrated into cement-polyacrylate composite grout to improve its interfacial bonding.First,four-point bending tests were conducted,and the Monte Carlo method combined with the simplex search algorithm was employed to determine the variations in shear cohesion and static friction parameters.The results reveal that GO can significantly increase both the tensile and shear cohesion of the grout-limestone interface,but minimally affects the interfacial friction coefficient.Second,nuclear magnetic resonance(NMR)and scanning electron microscopy(SEM)tests were performed.The results indicate that GO nanosheets result in a squamaceous microstructure of the grout consolidation mass,increasing the adhesion of the grout-limestone interface.Moreover,spiny Aft(ettringite)clusters can be induced in limestone fracture surfaces by GO,which could serve as anchors for limestone and grout consolidation mass.
基金supported by the Leading Edge Technology of Jiangsu Province(BK20222009-X.Z.,BK20202008-X.Z.)Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)National Undergraduate Innovation Training Program of NUAA(202410287179Y).
文摘Zn-based thermal charging devices,utilizing the synergistic effect of ion thermoextraction and thermodiffusion,are able to efficiently convert thermal energy into electrical energy and storage in the devices,making them a highly promising technology for low-grade heat recovery and utilization.However,the low output power density and energy conversion efficiency resulted by the slow diffusion kinetics of Zn^(2+)hinder their development.Herein,we present a highperformance thermal charging cell design using Zn^(2+)/NH_(4)^(+)hybrid ion electrolyte,which not only maintains the high output voltage of the Zn-based thermoelectric system,but also significantly enhances the output power density due to the fast diffusion kinetics of NH_(4)^(+).Based on this strategy,the thermal charging cell displays a high thermopower of 12.5 mV K^(-1)and an excellent normalized power density of 19.6 mW m^(-2)K^(-2)at a temperature difference of 35 K.The Carnot-relative efficiency is as high as 12.74%.Moreover,it can operate continuously for over 72 h when the temperature difference persists,achieving a balance between thermoelectric conversion and output.This work provides a simple and effective strategy for the design of high-performance thermal charging cells for low-grade heat conversion and utilization.
基金funded by the National Natural Science Foundation of China(No.52308316)Key Laboratory of Rock Mechanics and Geohazards of Zhejiang Province(No.ZJRMG-2022-01)+1 种基金Fudamental Research Funds for the CentralUniversities,CHD(No.300102265303)the Science and Technology Innovation Project of China Coal Technology&Engineering Group Shenyang Engineering Company(No.NKJ001-2025).
文摘In the steel slag-based mine backfill cementitious material systems,the hydration reaction mechanisms and synergistic effects of steel slag(SS),granulated blast furnace slag(GBFS),and desulfurization gypsum(DG)are crucial for performance optimization and regulation.However,existing studies have yet to fully reveal the underlying synergistic mechanisms,which limits the application and promotion of high SS content in mine backfill and low-carbon building materials.This study systematically explores the synergistic effects between various solid wastes and their regulation of the hydration process in the SS-based cementitious system through multi-scale characterization techniques.The results show that GBFS,by releasing active Si^(4+)and Al^(3+),triggers a synergistic activation effect with Ca^(2+)provided by SS,promoting the formation of C-S-H gel and ettringite,significantly optimizing the hardened paste microstructure.When the GBFS content reaches 30%,the C-S-H content increases by 40.8%,the pore size distribution improves,the proportion of large pores decreases by 68.7%,and the 90-day compressive strength increases to 5 times that of the baseline group.The sulfate activation effect of DG accelerates the hydration of silicate minerals,but excessive incorporation(>16%)can lead to microcracks caused by the expansion of AFt crystals,resulting in a strength reduction.Under the synergistic effect of 8%DG and 30%GBFS,the hydration reaction is most intense,with the peak heat release rate reaching 0.92 mW/g and the cumulative heat release amount being 240 J/g.By constructing a“SS-GBFS-DG-cement”quaternary synergistic system(mass ratio range:SS:GBFS:cement:DG=(50–62):(20–40):10:(8–12)),the matching of active components in high-content SS systems was optimized,significantly improving microstructural defects and meeting engineering application requirements.This study provides a theoretical basis for the component design and performance regulation of high-content SS-based cementitious materials.
基金supported by the Key Research Program of the Institute of Geology&Geophysics,CAS(Grant No.IGGCAS-201903).
文摘Natural gas hydrates widely accumulate in submarine sediments composed of clay minerals.However,due to the complex physiochemistry and micron-sized particles of clay minerals,their effects on methane hydrate(MH)formation and dissociation are still in controversy.In this study,montmorillonite and illite were separately mixed with quartz sand to investigate their effects on MH formation and dissociation.The microstructure of synthesized samples was observed by cryo-SEM innovatively to understand the effects of montmorillonite and illite on MH phase transition in micron scale.Results show that montmorillonite and illite both show the inhibition on MH formation kinetics and water-to-hydrate conversion,and illite shows a stronger inhibition.The 10 wt%montmorillonite addition significantly retards MH formation rate,and the 20 wt%montmorillonite has a less inhibition on the rate.The increase of illite mass ratio(0-20 wt%)retards the rate of MH formation.As the content of clay minerals increase,the water-to-hydrate conversion decreases.Cryo-SEM images presented that montmorillonite aggregates separate as individual clusters while illite particles pack as face-to-face configuration under the interaction with water.The surface-overlapped illite aggregates would make sediments pack tightly,hinder the contact between gas and water,and result in the more significant inhibition on MH formation kinetics.Under the depressurization method,the addition of clay minerals facilitates MH dissociation rate.Physicochemical properties of clay minerals and MH distribution in the pore space lead to the faster dissociation rate in clay-containing sediments.The results of this study would provide beneficial guides on geological investigations and optimizing strategies of natural gas production in marine hydrate-bearing sediments.
基金supported by the National Research Foundation of Korea(NRF)funded by the Korean government(MSIT)(No.2022R1A2C1006743).
文摘This study presents a novel approach to improving the anticorrosive performance of AZ31 Mg alloy by exploiting the role of the hydration reaction to induce interactions between Quinolin-8-ol(8HQ)molecules and the porous MgO layer formed via plasma electrolytic oxidation(PEO).The AZ31 Mg alloy,initially coated with a PEO layer,underwent a dipping treatment in an ethanolic solution of 0.05 M 8HQ at 50℃ for 3 h.The results were compared with those from a different procedure where the PEO layer was subjected to a hydration reaction for 2 h at 90℃ before immersion in the 8HQ solution under the same conditions.The hydration treatment played a crucial role by converting MgO to Mg(OH)_(2),significantly enhancing the surface reactivity.This transformation introduced hydroxyl groups(−OH)on the surface,which facilitated donor-acceptor interactions with the electron-accepting sites on 8HQ molecules.The calculated binding energy(Ebinding)from DFT indicated that the interaction energy of 8HQ with Mg(OH)_(2) was lower compared to 8HQ with MgO,suggesting easier adsorption of 8HQ molecules on the hydrated surface.This,combined with the increased number of active sites and enhanced surface area,allowed for extensive surface coverage by 8HQ,leading to the formation of a stable,flake-like protective layer that sealed the majority of pores on the PEO layer.DFT calculations further suggested that the hydration treatment provided multiple active sites,enabling effective contact with 8HQ and rapid electron transfer,creating ideal conditions for charge-transfer-induced physical and chemical bonding.This study shows that hydration and 8HQ treatments significantly enhance the corrosion resistance of Mg alloys,highlighting their potential for advanced anticorrosive coatings.
基金The financial support from the National Natural Science Foundation of China(22127812,22278433,22178379)the National Key Research and Development Program of China(2021YFC2800902)are gratefully acknowledged。
文摘The mechanism of hydrate-based desalination is that water molecules would transfer to the hydrate phase during gas hydrate formation process,while the salt ions would be conversely concentrated in the unreacted saltwater.However,the salt concentration of hydrate decomposed water and the desalination degree of hydrate phase are still unclear.The biggest challenge is how to effectively separate the hydrate phase and the remaining unreacted salt water,and then decompose the hydrate phase to measure the salt concentration of hydrate melt water.This work developed an apparatus and pressure-driven filtration method to efficiently separate the hydrate phase and the remaining unreacted saltwater.On this basis,the single hydrate phase was obtained,then it was dissociated and the salt concentration of hydrate melt water was measured.The experimental results demonstrate that when the initial salt mass concentration is 0.3% to 8.0%,the salt removal efficiency for NaCl solution is 15.9% to 29.8%by forming CO_(2) hydrate,while for CaCl_(2) solution is 28.9%to 45.5%.The solute CaCl_(2) is easier to be removed than solute NaCl.In addition,the salt removal efficiency for forming CO_(2) hydrate is higher than that for forming methane hydrate.The multi-stage desalination can continuously decrease the salt concentration of hydrate dissociated water,and the salt removal efficiency per stage is around 20%.
基金supported by the Key Research and Development Special Tasks of Xinjiang,China (No.2022B01051-2)the National Natural Science Foundation of China (Nos.U23B2091,42372328,and 52478253)+1 种基金the Natural Science Foundation of Jiangsu Province,China (No.BK20240209)the Science and Technology Program Special Fund of Jiangsu Province (Frontier Leading Technology Basic Research) Major projects,China (No.BK 20222004)
文摘Using cemented rockfill to replace coal pillars offers an effective solution for reducing solid waste while ensuring the safety of gob-side entries.However,achieving the balance among low cost,high waste recycling rates,and adequate strength remains a significant challenge for cemented rockfill.This study used a composite alkali activator to activate gangue cemented rockfill.The compressive strength,scanning electron microscopy,energy dispersive spectrometer,mercury intrusion porosimetry,X-ray diffraction,and thermogra-vimetric tests were carried out to investigate the effect of the composite alkali activator proportion on the compressive strength,micro-structure,and composition of the cemented rockfill.The calcium silicate hydrate(C–S–H)molecular model of cemented rockfill was con-structed to explore the fracture evolution of the nucleated molecular structure under tension.The results show that compressive strength initially increased and then decreased with the activator proportion,the optimal activator proportion of 1:2 resulted in a 31.25%increase in strength at 3 d.This reasonable activator proportion strengthens the pozzolanic effect of gangue,and consumes more calcium hydroxide to inhibit its agglomeration,ultimately achieving the densification of microstructure.The activator proportion inevitably substitutes calcium ions with sodium ions in the C–S–H molecular model.The 12%substitution of calcium ions increases the adhesion between silicon chain layers,which is beneficial to the interlayer stress transfer.This work proposes a method for preparing low-cost cemented rockfill from al-kali-activated gangue,which can be used for solid waste recycling and reducing cement consumption to achieve low-carbon goals.
基金support of the National Natural Science Foundation of China(Grant No.52074332).
文摘Natural gas hydrates(hereinafter referred to as hydrates)are a promising clean energy source.However,their current development is far from reaching commercial exploitation.Reservoir stimulation tech-nology provides new approaches to enhance hydrate development effectiveness.Addressing the current lack of quantitative and objective methods for evaluating the fracability of hydrate reservoirs,this study clarifies the relationship between geological and engineering fracability and proposes a comprehensive evaluation model for hydrate reservoir fracability based on grey relational analysis and the criteria importance through intercriteria correlation method.By integrating results from hydraulic fracturing experiments on hydrate sediments,the fracability of hydrate reservoirs is assessed.The concept of critical construction parameter curves for hydrate reservoirs is introduced for the first time.Additionally,two-dimensional fracability index evaluation charts and three-dimensional fracability construction condition discrimination charts are established.The results indicate that as the comprehensive fracability index increases,the feasibility of forming fractures in hydrate reservoirs improves,and the required normalized fracturing construction parameters gradually decrease.The accuracy rate of the charts in judging experimental results reached 89.74%,enabling quick evaluations of whether hydrate reservoirs are worth fracturing,easy to fracture,and capable of being fractured.This has significant engineering implications forthehydraulicfracturingof hydratereservoirs.
基金supported by the Russian Science Foundation(23-29-00830).
文摘Morphology and growth rate of carbon dioxide hydrate on the interface between liquid carbon dioxide and humic acid solutions were studied in this work.It was found that after the growth of the hydrate film at the interface,further growth of hydrate due to the suction of water in the capillary system formed between the wall of the cuvette and the end boundary of the hydrate layer occurs.Most probably,substantial effects on the formation of this capillary system may be caused by variations in reactor wall properties,for example,hydrophobic-hydrophilic balance,roughness,etc.We found,that the rate of CO_(2) hydrate film growth on the surface of the humic acid aqueous solution is 4-fold to lower in comparison with the growth rate on the surface of pure water.We suppose that this is caused by the adsorption of humic acid associates on the surface of hydrate particles and,as a consequence,by the deceleration of the diffusion of dissolved carbon dioxide to the growing hydrate particle.
基金supported by the National Key R&D Program of China(No.2024YFB4206700)the Joint Geological Funds of the National Natural Science Foundation of China(No.U2244223)+5 种基金the China Scholarship Council Program(No.202404910533)the Guangdong Major Project of Basic and Applied Basic Research(No.2020B0301030003)the China Geological Survey Project(No.DD20211350)the Key Deployment Program of Chinese Academy of Sciences(Nos.YJKYYQ20190043,ZDBS-LY-DQC003,KFZD-SW-422,and ZDRW-ZS-2021-3-1)the Scientific Research and Technology Development Project of China National Petroleum Corporation(No.2022DJ5503)the Supercomputing Laboratory,IGGCAS.
文摘This study proposes and systematically evaluates an optimized integration of warm surface seawater injection with depressurization for the long-term exploitation of marine natural gas hydrates.By employing comprehensive multiphysics simulations guided by field data from hydrate production tests in the South China Sea,we pinpoint key operational parameters—such as injection rates,depths,and timings—that notably enhance production efficiency.The results indicate that a 3-phase hydrate reservoir transitions from a free-gas-dominated production stage to a hydrate-decomposition-dominated stage.Moderate warm seawater injection supplies additional heat during the hydrate decomposition phase,thereby enhancing stable production;however,excessively high injection rates can impede the depressurization process.Only injection at an appropriate depth simultaneously balances thermal supplementation and the pressure gradient,leading to higher overall productivity.A“depressurization-driven sensible-heat supply window”is introduced,highlighting that timely seawater injection following initial depressurization prolongs reservoir dissociation dynamics.In this study area,commencing seawater injection at 170 d of depressurization proved optimal.This optimized integration leverages clean and renewable thermal energy,providing essential insights into thermal supplementation strategies with significant implications for sustainable,economically feasible,and efficient commercial-scale hydrate production.
基金supported by the National Key Research and Development Program of China for Young Scientists(Grant No.2023YFB4104100)the National Natural Science Foundation of China(Grant 52176057)+3 种基金the National Key Research and Development Program of China(Grant No.2023YFB4104201)supported by the Unveiling and Commanding Foundation of Liaoning Province(Grant 2023JH1/10400003)the Shenzhen Science and Technology Program(No.JCYJ20220818095605012)supported by the Young Changjiang Scholars programme of China。
文摘Carbon dioxide(CO_(2))marine sequestration by hydrate method is considered as one of the options to effectively achieve carbon reduction.However,the slow rate of hydrate formation becomes a major limiting factor.In view of the gas-water mass transfer problem which is the main obstacle,this paper explored the amphiphilic amino acids to promote the formation of CO_(2)hydrate and used low-field nuclear magnetic resonance(LNMR)to conduct an innovative study on its kinetics and spatiotemporal distribution.By comparing the promotion performance of L-methionine(L-met),L-cysteine(L-cys),and L-valine(L-val),the comprehensive kinetic promotion ability of L-met was the highest,reducing the induction time by 60.0%,achieving the maximum water conversion of about 57.0%within only 1 h,and reaching a final CO_(2)storage efficiency of 84.6%.LNMR results showed that hydrates were preferentially formed in large and medium pores in the reservoir region.Interestingly,we found that the combined effect of hydrophilic groups and the hydrophobic side chain of L-met not only promoted the rearrangement of water molecules and provided more nucleation sites,but also created a localized CO_(2)supersaturated environment and facilitated gas-water redistribution.Meanwhile,L-met promoted the formation of a hydrate porous structure to ensure the continuous formation of hydrates.This study innovatively explored CO_(2)hydrate formation behavior in amphiphilic amino acids and laid a theoretical foundation for the realization of CO_(2)marine sequestration by hydrate method.
