Soil liquefaction,a seismic-induced phenomenon,is of significant concern in geotechnical engineering due to its potential to cause severe structural damage and ground instability during earthquakes.This study explores...Soil liquefaction,a seismic-induced phenomenon,is of significant concern in geotechnical engineering due to its potential to cause severe structural damage and ground instability during earthquakes.This study explores the prediction of the Liquefaction Severity Index(LSI)by integrating extensive borehole investigation data with seismic records from the Kahramanmara?(M_(w)7.8)and Hatay(M_(w)6.4)earthquakes that occurred in 2023.Nine machine learning models,Random Forest(RF),M5P,REPTree,IBk,Random Tree(RT),Gaussian Processes(GP),SMOreg,Locally Weighted Learning(LWL),and Linear Regression(LR),were employed with 10-fold cross-validation to ensure reliable predictions.Twelve geotechnical and seismic parameters,groundwater level,earthquake magnitude,peak ground acceleration,V_(s30),dominant frequency,dominant period,longitudinal wave velocity,dynamic modulus of elasticity,dynamic shear modulus,modulus of incompressibility,standard penetration test(SPT)values,and cyclic stress ratio(CSR)values,were utilized as inputs.The analysis results were evaluated with respect to RMSE,MAE,R2,RAE,P/M,error category limits,Taylor diagram,and relative importance of input parameters.Among the models,Random Forest outperformed with an R2 of 0.94,MAE of 2.35,with minimal prediction errors,followed by M5P and REPTree.Error analysis indicated that 80%of Random Forest and REPTree predictions fell within±7,while M5P showed slightly higher variability.Model-based feature ranking demonstrated that Cyclic Stress Ratio(CSR),Ground Water Level(GWL),and Standard Penetration Test(SPT)value emerged as dominant predictors.These findings highlight the study’s contribution to developing a reliable,datadriven framework for LSI prediction,offering a robust basis for improving site-specific liquefaction risk assessment and informed geotechnical decisionmaking in future seismic events.展开更多
Earthquake-induced soil liquefaction poses significant risks to the stability of geotechnical structures worldwide.An understanding of the liquefaction triggering,and the post-failure large deformation behaviour is es...Earthquake-induced soil liquefaction poses significant risks to the stability of geotechnical structures worldwide.An understanding of the liquefaction triggering,and the post-failure large deformation behaviour is essential for designing resilient infrastructure.The present study develops a Smoothed Particle Hydrodynamics(SPH)framework for earthquake-induced liquefaction hazard assessment of geotechnical structures.The coupled flowdeformation behaviour of soils subjected to cyclic loading is described using the PM4Sand model implemented in a three-phase,single-layer SPH framework.A staggered discretisation scheme based on the stress particle SPH approach is adopted to minimise numerical inaccuracies caused by zero-energy modes and tensile instability.Further,non-reflecting boundary conditions for seismic analysis of semi-infinite soil domains using the SPH method are proposed.The numerical framework is employed for the analysis of cyclic direct simple shear test,seismic analysis of a level ground site,and liquefaction-induced failure of the Lower San Fernando Dam.Satisfactory agreement for liquefaction triggering and post-failure behaviour demonstrates that the SPH framework can be utilised to assess the effect of seismic loading on field-scale geotechnical structures.The present study also serves as the basis for future advancements of the SPH method for applications related to earthquake geotechnical engineering.展开更多
Hydrothermal liquefaction technology is an effective method for the resource utilization and energy conversion of biomass under the dual-carbon context,facilitating the conversion of biomass into liquid fuels and high...Hydrothermal liquefaction technology is an effective method for the resource utilization and energy conversion of biomass under the dual-carbon context,facilitating the conversion of biomass into liquid fuels and high-value chemicals.This paper reviews the latest advancements in the production of liquid fuels and chemicals from biomass hydrothermal liquefaction.It briefly introduces the effects of different types of biomass,such as organic waste,lignocellulosic materials,and algae,on the conversion efficiency and product yield during hydrothermal liquefaction.The specific mechanisms of solvent and catalyst systems in the hydrothermal liquefaction process are analyzed in detail.Compared to water and organic solvents,the biphasic solvent system yields higher concentrations of furan platform compounds,and the addition of an appropriate amount of NaCl to the solvent significantly enhances product yield.Homogeneous catalysts exhibit advantages in reaction rate and selectivity but are limited by high costs and difficulties in separation and recovery.In contrast,heterogeneous catalysts possess good separability and regeneration capabilities and can operate under high-temperature conditions,but their mass transfer efficiency and deactivation issues may affect catalytic performance.The direct hydrothermal catalytic conversion of biomass is also discussed for the efficient production of chemicals and fuels such as hexanol,ethylene glycol,lactic acid,and C5/C6 liquid alkanes.Finally,the advantages and current challenges of producing liquid fuels and chemicals from biomass hydrothermal liquefaction are thoroughly analyzed,along with potential future research directions.展开更多
The migration/transformation characteristics of heavy metals and polycyclic aromatic hydrocarbons(PAHs) during the co-liquefaction of pig manure and rice straw/wood sawdust were explored in this study.More than 87% of...The migration/transformation characteristics of heavy metals and polycyclic aromatic hydrocarbons(PAHs) during the co-liquefaction of pig manure and rice straw/wood sawdust were explored in this study.More than 87% of the heavy metals in feedstocks were enriched in hydrochars.The decreased proportion of active heavy metals in the hydrochars suggested partial passivation of the heavy metals.The pollution degree and risk of heavy metals were significantly mitigated from high and considerable levels in pig manure to moderate and low levels in hydrochar,respectively.Compared with commercial diesel,bio-oil products still contained an undesirable amount of heavy metals.PAHs were re-synthesized during liquefaction,with a net synthesis amount of 29.65-73.98 mg·kg^(-1).Moreover,the PAHs mainly existed in bio-oils,with a content of 57.32-132.33 mg·kg^(-1) and a toxicity equivalent of3.25-8.19 mg·kg^(-1).Compared to pig manure,the hydrochars presented a lower content of PAHs(1.76-3.53 mg·kg^(-1) versus 3.73 mg·kg^(-1)) and a smaller toxicity equivalent(0.14-0.22 mg·kg^(-1) versus0.26 mg·kg^(-1)).Interestingly,introducing lignocellulose(especially for rice straw) during the liquefaction of pig manure further mitigated the pollution degree/risk of heavy metals and PAHs.Overall,hydrochar reached a safe utilization level,while bio-oil products needed further clarification.展开更多
When assessing seismic liquefaction potential with data-driven models,addressing the uncertainties of establishing models,interpreting cone penetration tests(CPT)data and decision threshold is crucial for avoiding bia...When assessing seismic liquefaction potential with data-driven models,addressing the uncertainties of establishing models,interpreting cone penetration tests(CPT)data and decision threshold is crucial for avoiding biased data selection,ameliorating overconfident models,and being flexible to varying practical objectives,especially when the training and testing data are not identically distributed.A workflow characterized by leveraging Bayesian methodology was proposed to address these issues.Employing a Multi-Layer Perceptron(MLP)as the foundational model,this approach was benchmarked against empirical methods and advanced algorithms for its efficacy in simplicity,accuracy,and resistance to overfitting.The analysis revealed that,while MLP models optimized via maximum a posteriori algorithm suffices for straightforward scenarios,Bayesian neural networks showed great potential for preventing overfitting.Additionally,integrating decision thresholds through various evaluative principles offers insights for challenging decisions.Two case studies demonstrate the framework's capacity for nuanced interpretation of in situ data,employing a model committee for a detailed evaluation of liquefaction potential via Monte Carlo simulations and basic statistics.Overall,the proposed step-by-step workflow for analyzing seismic liquefaction incorporates multifold testing and real-world data validation,showing improved robustness against overfitting and greater versatility in addressing practical challenges.This research contributes to the seismic liquefaction assessment field by providing a structured,adaptable methodology for accurate and reliable analysis.展开更多
On March 28,2025,a catastrophic M 7.9 earthquake shook central Myanmar,causing extensive damage to buildings,significant casualties,and substantial economic loss,making it one of the most severe natural disasters Myan...On March 28,2025,a catastrophic M 7.9 earthquake shook central Myanmar,causing extensive damage to buildings,significant casualties,and substantial economic loss,making it one of the most severe natural disasters Myanmar has faced in recent years.During an on-site investigation that lasted two weeks,widely spreading liquefaction phenomena and associated damage to buildings and other facilities were investigated in 16 villages or districts in the seismic zones,involving hundreds of residential houses,two large bridges,underground storage tanks,etc.Ground fissures generated by liquefaction tore apart houses,which contributed to a significant impact on house damage.The loss of ground bearing capacity is another impact of liquefaction with regard to structural damage,causing the subsidence and tilting of houses.Several consequences of liquefaction were identified,such as lateral spreading,which demolishes houses and causes casualties,as well as damage to two large bridges as a result of lateral spreading.The cases of liquefaction following the Myanmar earthquake reported on herein provide data and lessons for future seismic desigs to help prevent such disasters in Southeast Asia.Through analyzing the phenomena and characteristics of soil liquefaction,the methods and techniques for liquefaction hazard mitigation in other countries also can be improved.展开更多
Seismic-induced liquefaction of sandy soils can fail foundations in the vicinity of buildings.To investigate the effect of a non-free field subsurface seismic history on the ability of saturated sandy soils to resist ...Seismic-induced liquefaction of sandy soils can fail foundations in the vicinity of buildings.To investigate the effect of a non-free field subsurface seismic history on the ability of saturated sandy soils to resist liquefaction,four shaking events with different accelerations were input to the sandy soils in the non-free-field.The results of the study revealed that:(1)Shallow soils that are not free-field undergo acceleration amplification effects after being subjected to seismic loading.(2)Building overburden pressure reduces the sensitivity of the shallow soils directly below in small and moderate earthquakes,which are more prone to rearranging and forming unstable structures under strong seismic effects.The excess pore pressure response on the load side resembles that of a free site,with the depth range of the liquefaction strength of soils affected by the seismic history,increasing progressively as input seismic intensity increases.(3)After experiencing earthquakes of different intensities,the excess pore pressure directly below the building overburden pressure at 0.1 m and 0.2 m is greater than that at the side.At the same time,the side of the building structure is more prone to liquefaction than the soil directly below it.展开更多
Liquefaction is one of the prominent factors leading to damage to soil and structures.In this study,the rela-tionship between liquefaction potential and soil parameters is determined by applying feature importance met...Liquefaction is one of the prominent factors leading to damage to soil and structures.In this study,the rela-tionship between liquefaction potential and soil parameters is determined by applying feature importance methods to Random Forest(RF),Logistic Regression(LR),Multilayer Perceptron(MLP),Support Vector Machine(SVM)and eXtreme Gradient Boosting(XGBoost)algorithms.Feature importance methods consist of permuta-tion and Shapley Additive exPlanations(SHAP)importances along with the used model’s built-in feature importance method if it exists.These suggested approaches incorporate an extensive dataset of geotechnical parameters,historical liquefaction events,and soil properties.The feature set comprises 18 parameters that are gathered from 161 field cases.Algorithms are used to determine the optimum performance feature set.Compared to other approaches,the study assesses how well these algorithms predict soil liquefaction potential.Early findings show that the algorithms perform well,demonstrating their capacity to identify non-linear connections and improve prediction accuracy.Among the feature set,σ,v(psf),MSF,CSRσ,v,FC%,Vs*,40f t(f ps)and N1,60,CS are the ones that have the highest deterministic power on the result.The study’s contribution is that,in the absence of extensive data for liquefaction assessment,the proposed method estimates the liquefaction potential using five parameters with promising accuracy.展开更多
Coal direct liquefaction technology is a crucial contemporary coal chemical technology for efficient and clean use of coal resources. The development of direct coal liquefaction technology and the promotion of alterna...Coal direct liquefaction technology is a crucial contemporary coal chemical technology for efficient and clean use of coal resources. The development of direct coal liquefaction technology and the promotion of alternative energy sources are important measures to guarantee energy security and economic security. However, several challenges need to be addressed, including low conversion rate, inadequate oil yield, significant coking, demanding reaction conditions, and high energy consumption. Extensive research has been conducted on these issues, but further exploration is required in certain aspects such as pyrolysis of macromolecules during the liquefaction process, hydrogen activation, catalysts' performance and stability, solvent hydrogenation, as well as interactions between free radicals to understand their mechanisms better. This paper presents a comprehensive analysis of the design strategy for efficient catalysts in coal liquefaction, encompassing the mechanism of coal liquefaction, catalyst construction,and enhancement of catalytic conversion efficiency. It serves as a comprehensive guide for further research endeavors. Firstly, it systematically summarizes the conversion mechanism of direct coal liquefaction, provides detailed descriptions of various catalyst design strategies, and especially outlines the catalytic mechanism. Furthermore, it addresses the challenges and prospects associated with constructing efficient catalysts for direct coal liquefaction based on an understanding of their action mechanisms.展开更多
Liquid hydrogen has attracted much attention due to its high energy storage density and suitability for long-distance transportation.An efficient hydrogen liquefaction process is the key to obtaining liquid hydrogen.I...Liquid hydrogen has attracted much attention due to its high energy storage density and suitability for long-distance transportation.An efficient hydrogen liquefaction process is the key to obtaining liquid hydrogen.In an effort to determine the parameter optimization of the hydrogen liquefaction process,this paper employed process simulation software Aspen HYSYS to simulate the hydrogen liquefaction process.By establishing a dynamic model of the unit module,this study carried out dynamic simulation optimization based on the steady-state process and process parameters of the hydrogen liquefaction process and analyzed the dynamic characteristics of the process.Based on the pressure drop characteristic experiment,an equation for the pressure drop in the heat exchanger was proposed.The heat transfer of hydrogen conversion was simulated and analyzed,and its accuracy was verified by comparison with the literature.The dynamic simulation of a plate-fin heat exchanger was carried out by coupling heat transfer simulation and the pressure drop experiment.The results show that the increase in inlet temperature(5℃and 10℃)leads to an increase in specific energy consumption(0.65%and 1.29%,respectively)and a decrease in hydrogen liquefaction rate(0.63%and 2.88%,respectively).When the inlet pressure decreases by 28.57%,the hydrogen temperature of the whole liquefaction process decreases and the specific energy consumption increases by 52.94%.The research results are of great significance for improving the operating efficiency of the refrigeration cycle and guiding the actual liquid hydrogen production.展开更多
Rapidly obtaining spatial distribution maps of secondary disasters triggered by strong earthquakes is crucial for understanding the disaster-causing processes in the earthquake hazard chain and formulating effective e...Rapidly obtaining spatial distribution maps of secondary disasters triggered by strong earthquakes is crucial for understanding the disaster-causing processes in the earthquake hazard chain and formulating effective emergency response measures and post-disaster reconstruction plans.On April 3,2024,a M_(W)7.4 earthquake struck offshore east of Hualien,Taiwan,China,which triggered numerous coseismic landslides in bedrock mountain regions and severe soil liquefaction in coastal areas,resulting in significant economic losses.This study utilized postearthquake emergency data from China's high-resolution optical satellite imagery and applied visual interpretation method to establish a partial database of secondary disasters triggered by the 2024 Hualien earthquake.A total of 5348 coseismic landslides were identified,which were primarily distributed along the eastern slopes of the Central Mountain Range watersheds.In high mountain valleys,these landslides mainly manifest as localized bedrock collapses or slope debris flows,causing extensive damage to highways and tourism facilities.Their distribution partially overlaps with the landslide concentration zones triggered by the 1999 Chi-Chi earthquake.Additionally,6040 soil liquefaction events were interpreted,predominantly in the Hualien Port area and the lowland valleys of the Hualien River and concentrated within the IX-intensity zone.Widespread surface subsidence and sand ejections characterized soil liquefaction.Verified against local field investigation data in Taiwan,rapid imaging through post-earthquake remote sensing data can effectively assess the distribution of coseismic landslides and soil liquefaction within high-intensity zones.This study provides efficient and reliable data for earthquake disaster response.Moreover,the results are critical for seismic disaster mitigation in high mountain valleys and coastal lowlands.展开更多
By means of X ray and gas chromatography analysis, the crystalline structure of untreated wood , alkali treated wood and benzylated wood and their liquefaction in toluene and tetrahydrofufan with HCl as a catalyst we...By means of X ray and gas chromatography analysis, the crystalline structure of untreated wood , alkali treated wood and benzylated wood and their liquefaction in toluene and tetrahydrofufan with HCl as a catalyst were studied .The upper solution of benzylated wood was also studied by GC MS analysis. It proved that the introduction of bulky benzyl group in wood significantly changed the crystalline structure of wood ,enlarging the free volume which facilitated the penetration of solvent into the matrix of treated wood, thus tremendously enhancing thesolubility in solvent,compared to untreated wood and alkali treated wood. The percentage of residue decreased and the combined solvent increased with the increase of weight gain revealed that the liquefaction process became easy. Furthermore, the factors that influenced the liquefaction of benzylated wood were investigated. It showed that the liquefaction performance was improved with the increase of liquefaction time and the amount of catalyst when toluene was used as a solvent, especially in the presence of THF as solvent, there existed the optimum liquefaction time and the amount of catalyst .展开更多
In this research,molecular structure models were developed respectively for Shenhua coal vitrinite concentrates(SDV)and inertinite concentrates(SDI),on the basis of information on constitutional unit of Shenhau coal a...In this research,molecular structure models were developed respectively for Shenhua coal vitrinite concentrates(SDV)and inertinite concentrates(SDI),on the basis of information on constitutional unit of Shenhau coal and elemental analysis results obtained from^(13)C-NMR analysis characterization,FTIR analysis characterization,X-ray diffraction XRD and XPS analysis characterization.It can be observed from characterization data and molecular structure models that the structure of SDV and SDI is dominated by aromatic hydrocarbon,with aromaticity of SDI higher than that of SDV;SDV mainly consists of small molecule basic structure unit,while SDI is largely made from macromolecular structure unit.Based on bond-level parameters of the molecular model,the research found through the autoclave experiment that vitrinite liquefaction process goes under thermodynamics control and inertinite liquefaction process under dynamics control.The research developed an efficient directional direct coal liquefaction technology based on the maceral characteristics of Shenhua coal,which can effectively improve oil yield and lower gas yield.展开更多
To clarify the influencing factors of liquefaction of wood in phenol using phosphoric acid as a catalyst and get its liquefaction technology, a study on the liquefaction technology of Chinese fir (Cunninghamia lanceol...To clarify the influencing factors of liquefaction of wood in phenol using phosphoric acid as a catalyst and get its liquefaction technology, a study on the liquefaction technology of Chinese fir (Cunninghamia lanceolata) and poplar (triploid Populus tomentosa Carr) under different conditions was conducted. The results indicate that the residue rate decreases with the increase of liquefaction temperature, liquefaction time, catalyst content or liquid ratio. It is also found that the optimum condition of liquefaction for poplar is estimated as: the reaction temperature of 180 C, the reaction time of 2.5 h, liquid ratio (phenol/wood ratio) of 4.5 and catalyst content of 8%, and 4.2% residue rate could be obtained. Under the processing parameters of temperature 180 C, the reaction time of 2.5 h, liquid ratio (phenol/wood ratio) of 4 and catalyst content of 10%, the residue rate of Chinese fir can reach 5.6%.展开更多
Quaternary silt is widely distributed in China and easily liquefies during earthquakes. To identify the influence of the dry density on the liquefaction behaviour of Quaternary silt, 40 cyclic triaxial liquefaction te...Quaternary silt is widely distributed in China and easily liquefies during earthquakes. To identify the influence of the dry density on the liquefaction behaviour of Quaternary silt, 40 cyclic triaxial liquefaction tests were performed on loose silt(dry density rd=1.460 g/cm^3) and dense silt(rd=1.586 g/cm^3) under different cyclic stress ratios(CSRs) to obtain liquefaction assessment criteria, determine the liquefaction resistance, improve the excess pore water pressure(EPWP) growth model and clarify the relationship between the shear modulus and damping ratio. The results indicate that the initial liquefaction assessment criteria for the loose and dense silts are a double-amplitude axial strain of 5% and an EPWP ratio of 1. The increase in the anti-liquefaction ability for the dense silt is more significant under lower confining pressures. The CSR of loose silt falls well within the results of the sandy silt and Fraser River silt, and the dense silt exhibits a higher liquefaction resistance than the sand-silt mixture. The relationships between the CSR and loading cycles were obtained at a failure strain of 1%. The EPWP development in the dense and loose silts complies with the "fast-stable" and "fast-gentle-sharp" growth modes, respectively. The power function model can effectively describe the EPWP growth characteristics of the dense silt. Finally, based on the liquefaction behaviour of silt, a suggestion for reinforcing silt slopes or foundations is proposed.展开更多
The nonlinear variation of wave is commonly seen in nearshore area,and the resulting seabed response and liquefaction are of high concern to coastal engineers.In this study,an analytical formula considering the nonlin...The nonlinear variation of wave is commonly seen in nearshore area,and the resulting seabed response and liquefaction are of high concern to coastal engineers.In this study,an analytical formula considering the nonlinear wave skewness and asymmetry is adopted to provide wave pressure on the seabed surface.The liquefaction depth attenuation coefficient and width growth coefficient are defined to quantitatively characterize the nonlinear effect of wave on seabed liquefaction.Based on the 2D full dynamic model of wave-induced seabed response,a detailed parametric study is carried out in order to evaluate the influence of the nonlinear variation of wave loadings on seabed liquefaction.Further,new empirical prediction formulas are proposed to fast predict the maximum liquefaction under nonlinear wave.Results indicate that(1)Due to the influence of wave nonlinearity,the vertical transmission of negative pore water pressure in the seabed is hindered,and therefore,the amplitude decreases significantly.(2)In general,with the increase of wave nonlinearity,the liquefaction depth of seabed decreases gradually.Especially under asymmetric and skewed wave loading,the attenuation of maximum seabed liquefaction depth is the most significant among all the nonlinear wave conditions.However,highly skewed wave can cause the liquefaction depth of seabed greater than that under linear wave.(3)The asymmetry of wave pressure leads to the increase of liquefaction width,whereas the influence of skewedness is not significant.(4)Compared with the nonlinear waveform,seabed liquefaction is more sensitive to the variation of nonlinear degree of wave loading.展开更多
The cyclic hydrogenation technology in a direct coal liquefaction process relies on the dissolved hydrogen of the solvent or oil participating in the hydrogenation reaction.Thus,a theoretical basis for process optimiz...The cyclic hydrogenation technology in a direct coal liquefaction process relies on the dissolved hydrogen of the solvent or oil participating in the hydrogenation reaction.Thus,a theoretical basis for process optimization and reactor design can be established by analyzing the solubility of hydrogen in liquefaction solvents.Experimental studies of hydrogen solubility in liquefaction solvents are challenging due to harsh reaction conditions and complex solvent compositions.In this study,the composition and content of liquefied solvents were analyzed.As model compounds,hexadecane,toluene,naphthalene,tetrahydronaphthalene,and phenanthrene were chosen to represent the liquefied solvents in chain alkanes and monocyclic,bicyclic,and tricyclic aromatic hydrocarbons.The solubility of hydrogen X(mol/mol)in pure solvent components and mixed solvents(alkanes and aromatics mixed in proportion to the chain alkanes+bicyclic aromatic hydrocarbons,bicyclic saturated aromatic hydrocarbons+bicyclic aromatic hydrocarbons,and bicyclic aromatic hydrocarbons+compounds containing het-eroatoms composed of mixed components)are determined using Aspen simulation at temperature and pressure conditions of 373–523 K and 2–10 MPa.The results demonstrated that at high temperatures and pressures,the solubility of hydrogen in the solvent increases with the increase in temperature and pressure,with the pressure having a greater impact.Further-more,the results revealed that hydrogen is more soluble in straight-chain alkanes than in other solvents,and the solubility of eicosanoids reaches a maximum of 0.296.The hydrogen solubility in aromatic ring compounds decreased gradually with an increase in the aromatic ring number.The influence of chain alkanes on the solubility of hydrogen predominates in a mixture of solvents with different mixing ratios of chain alkanes and aromatic hydrocarbons.The solubility of hydrogen in mixed aromatic solvents is less than that in the corresponding single solvents.Hydrogen is less soluble in solvent compounds containing heteroatoms than in compounds without heteroatoms.展开更多
[Objective]This paper aimed at studying the liquefaction technology of chestnut shells [Method]Effects on chestnut shells liquefaction of six catalysts were studied,which were sodium hydroxide,sodium carbonate,acetic ...[Objective]This paper aimed at studying the liquefaction technology of chestnut shells [Method]Effects on chestnut shells liquefaction of six catalysts were studied,which were sodium hydroxide,sodium carbonate,acetic acid（99.5%）,phosphoric acid（85%）,hydrochloric acid（37%）,sulfuric acid（98%）.The research had analyzed the liquefaction effects of chestnut shells in presence of phenol and at liquefaction temperatures of 130,150 and 170 ℃,in which the proportion of added quantities of concentrated sulfuric acid,phosphoric acid,concentrated hydrochloric acid to phenol were 1%-6%.Properties of phenolic resin made from formaldehyde and phenol-liquefied products of chestnut shells catalyzed by concentrated sulfuric acid with an added amount of 4% at 150 ℃（WPF）were analyzed and compared with traditional phenolic formaldehyde resin（PF）.[Result]Acid catalysts were better than alkaline ones in the phenol-liquefaction of chestnut shells,and the liquefaction ratio increased with the increasing of acidic intensity.The liquefaction ratio had attained the maximum as 92.11 % when catalyzed by concentrated sulfuric acid with an added amount of 4% at 150 ℃.The phenolic resin made from the liquefied products of chestnut shells was basically in accordance with the standard of GB/T 14732-93 when the mass ratio of chestnut shells powders to phenol was 1∶3.[Conclusion]It was possible to produce phenolic resin with liquefied chestnut shells.展开更多
Earthquakes can cause violent liquefaction of the soil, resulting in unstable foundations that can cause serious damage to facilities such as buildings, roads, and dikes. This is a primary cause of major earthquake di...Earthquakes can cause violent liquefaction of the soil, resulting in unstable foundations that can cause serious damage to facilities such as buildings, roads, and dikes. This is a primary cause of major earthquake disasters. Therefore, the discrimination and prediction of earthquake-induced soil liquefaction has been a hot issue in geohazard research. The soil liquefaction assessment is an integral part of engineering practice. This paper evaluated a dataset of 435 seismic sand liquefaction events using machine learning algorithms. The dataset was analyzed using seven potential assessment parameters. Ten machine learning algorithms are evaluated for their ability to assess seismic sand liquefaction potential, including Linear Discriminant Analysis(LDA), Quadratic Discriminant Analysis(QDA), Naive Bayes(NB), KNearest Neighbor(KNN), Artificial Neural Network(ANN), Classification Tree(CT), Support Vector Machine(SVM), Random Forest(RF), e Xtreme Gradient Boosting(XGBoost), Light Gradient Boosting Machine(Light GBM). A 10-fold cross-validation(CV) method was used in the modeling process to verify the predictive performance of the machine learning models. The final percentages of significant parameters that influenced the prediction results were obtained as Cyclic Stress Ratio(CSR) and Shear-Wave Velocity( VS1) with 56% and 38%, respectively. The final machine learning algorithms identified as suitable for seismic sand liquefaction assessment were the CT, RF, XGBoost algorithms, with the RF algorithm performing best.展开更多
This work investigates the correlation between a large number of widely used ground motion intensity measures(IMs) and the corresponding liquefaction potential of a soil deposit during earthquake loading. In order to ...This work investigates the correlation between a large number of widely used ground motion intensity measures(IMs) and the corresponding liquefaction potential of a soil deposit during earthquake loading. In order to accomplish this purpose the seismic responses of 32 sloping liquefiable site models consisting of layered cohesionless soil were subjected to 139 earthquake ground motions. Two sets of ground motions, consisting of 80 ordinary records and 59 pulse-like near-fault records are used in the dynamic analyses. The liquefaction potential of the site is expressed in terms of the the mean pore pressure ratio, the maximum ground settlement, the maximum ground horizontal displacement and the maximum ground horizontal acceleration. For each individual accelerogram, the values of the aforementioned liquefaction potential measures are determined. Then, the correlation between the liquefaction potential measures and the IMs is evaluated. The results reveal that the velocity spectrum intensity(VSI) shows the strongest correlation with the liquefaction potential of sloping site. VSI is also proven to be a sufficient intensity measure with respect to earthquake magnitude and source-to-site distance, and has a good predictability, thus making it a prime candidate for the seismic liquefaction hazard evaluation.展开更多
基金supported by Osmaniye Korkut Ata University Scientific Research Projects Unit(Project No:OKüBAP-2024-PT1-015)。
文摘Soil liquefaction,a seismic-induced phenomenon,is of significant concern in geotechnical engineering due to its potential to cause severe structural damage and ground instability during earthquakes.This study explores the prediction of the Liquefaction Severity Index(LSI)by integrating extensive borehole investigation data with seismic records from the Kahramanmara?(M_(w)7.8)and Hatay(M_(w)6.4)earthquakes that occurred in 2023.Nine machine learning models,Random Forest(RF),M5P,REPTree,IBk,Random Tree(RT),Gaussian Processes(GP),SMOreg,Locally Weighted Learning(LWL),and Linear Regression(LR),were employed with 10-fold cross-validation to ensure reliable predictions.Twelve geotechnical and seismic parameters,groundwater level,earthquake magnitude,peak ground acceleration,V_(s30),dominant frequency,dominant period,longitudinal wave velocity,dynamic modulus of elasticity,dynamic shear modulus,modulus of incompressibility,standard penetration test(SPT)values,and cyclic stress ratio(CSR)values,were utilized as inputs.The analysis results were evaluated with respect to RMSE,MAE,R2,RAE,P/M,error category limits,Taylor diagram,and relative importance of input parameters.Among the models,Random Forest outperformed with an R2 of 0.94,MAE of 2.35,with minimal prediction errors,followed by M5P and REPTree.Error analysis indicated that 80%of Random Forest and REPTree predictions fell within±7,while M5P showed slightly higher variability.Model-based feature ranking demonstrated that Cyclic Stress Ratio(CSR),Ground Water Level(GWL),and Standard Penetration Test(SPT)value emerged as dominant predictors.These findings highlight the study’s contribution to developing a reliable,datadriven framework for LSI prediction,offering a robust basis for improving site-specific liquefaction risk assessment and informed geotechnical decisionmaking in future seismic events.
基金The insights gained through these works,particularly from projects IITD/IRD/CW14168,CW14469,and CW14378,have significantly contributed to the development of the analysis presented in this study。
文摘Earthquake-induced soil liquefaction poses significant risks to the stability of geotechnical structures worldwide.An understanding of the liquefaction triggering,and the post-failure large deformation behaviour is essential for designing resilient infrastructure.The present study develops a Smoothed Particle Hydrodynamics(SPH)framework for earthquake-induced liquefaction hazard assessment of geotechnical structures.The coupled flowdeformation behaviour of soils subjected to cyclic loading is described using the PM4Sand model implemented in a three-phase,single-layer SPH framework.A staggered discretisation scheme based on the stress particle SPH approach is adopted to minimise numerical inaccuracies caused by zero-energy modes and tensile instability.Further,non-reflecting boundary conditions for seismic analysis of semi-infinite soil domains using the SPH method are proposed.The numerical framework is employed for the analysis of cyclic direct simple shear test,seismic analysis of a level ground site,and liquefaction-induced failure of the Lower San Fernando Dam.Satisfactory agreement for liquefaction triggering and post-failure behaviour demonstrates that the SPH framework can be utilised to assess the effect of seismic loading on field-scale geotechnical structures.The present study also serves as the basis for future advancements of the SPH method for applications related to earthquake geotechnical engineering.
基金supported by the National Natural Science Foundation of China(Grant Nos.52306125,52176095)Natural Science Research Project of Colleges and Universities in Anhui Province(Nos.2022AH050311,KJ2020ZD29)Anhui Provincial Natural Science Foundation(No.2008085J25).
文摘Hydrothermal liquefaction technology is an effective method for the resource utilization and energy conversion of biomass under the dual-carbon context,facilitating the conversion of biomass into liquid fuels and high-value chemicals.This paper reviews the latest advancements in the production of liquid fuels and chemicals from biomass hydrothermal liquefaction.It briefly introduces the effects of different types of biomass,such as organic waste,lignocellulosic materials,and algae,on the conversion efficiency and product yield during hydrothermal liquefaction.The specific mechanisms of solvent and catalyst systems in the hydrothermal liquefaction process are analyzed in detail.Compared to water and organic solvents,the biphasic solvent system yields higher concentrations of furan platform compounds,and the addition of an appropriate amount of NaCl to the solvent significantly enhances product yield.Homogeneous catalysts exhibit advantages in reaction rate and selectivity but are limited by high costs and difficulties in separation and recovery.In contrast,heterogeneous catalysts possess good separability and regeneration capabilities and can operate under high-temperature conditions,but their mass transfer efficiency and deactivation issues may affect catalytic performance.The direct hydrothermal catalytic conversion of biomass is also discussed for the efficient production of chemicals and fuels such as hexanol,ethylene glycol,lactic acid,and C5/C6 liquid alkanes.Finally,the advantages and current challenges of producing liquid fuels and chemicals from biomass hydrothermal liquefaction are thoroughly analyzed,along with potential future research directions.
基金supported by the National Natural Science Foundation of China(21707056)the Natural Science Foundation of Jiangxi Province,China(20192BAB203019)the Jiangxi Province Graduate Innovation Special Fund Project(YC2022-S412)。
文摘The migration/transformation characteristics of heavy metals and polycyclic aromatic hydrocarbons(PAHs) during the co-liquefaction of pig manure and rice straw/wood sawdust were explored in this study.More than 87% of the heavy metals in feedstocks were enriched in hydrochars.The decreased proportion of active heavy metals in the hydrochars suggested partial passivation of the heavy metals.The pollution degree and risk of heavy metals were significantly mitigated from high and considerable levels in pig manure to moderate and low levels in hydrochar,respectively.Compared with commercial diesel,bio-oil products still contained an undesirable amount of heavy metals.PAHs were re-synthesized during liquefaction,with a net synthesis amount of 29.65-73.98 mg·kg^(-1).Moreover,the PAHs mainly existed in bio-oils,with a content of 57.32-132.33 mg·kg^(-1) and a toxicity equivalent of3.25-8.19 mg·kg^(-1).Compared to pig manure,the hydrochars presented a lower content of PAHs(1.76-3.53 mg·kg^(-1) versus 3.73 mg·kg^(-1)) and a smaller toxicity equivalent(0.14-0.22 mg·kg^(-1) versus0.26 mg·kg^(-1)).Interestingly,introducing lignocellulose(especially for rice straw) during the liquefaction of pig manure further mitigated the pollution degree/risk of heavy metals and PAHs.Overall,hydrochar reached a safe utilization level,while bio-oil products needed further clarification.
文摘When assessing seismic liquefaction potential with data-driven models,addressing the uncertainties of establishing models,interpreting cone penetration tests(CPT)data and decision threshold is crucial for avoiding biased data selection,ameliorating overconfident models,and being flexible to varying practical objectives,especially when the training and testing data are not identically distributed.A workflow characterized by leveraging Bayesian methodology was proposed to address these issues.Employing a Multi-Layer Perceptron(MLP)as the foundational model,this approach was benchmarked against empirical methods and advanced algorithms for its efficacy in simplicity,accuracy,and resistance to overfitting.The analysis revealed that,while MLP models optimized via maximum a posteriori algorithm suffices for straightforward scenarios,Bayesian neural networks showed great potential for preventing overfitting.Additionally,integrating decision thresholds through various evaluative principles offers insights for challenging decisions.Two case studies demonstrate the framework's capacity for nuanced interpretation of in situ data,employing a model committee for a detailed evaluation of liquefaction potential via Monte Carlo simulations and basic statistics.Overall,the proposed step-by-step workflow for analyzing seismic liquefaction incorporates multifold testing and real-world data validation,showing improved robustness against overfitting and greater versatility in addressing practical challenges.This research contributes to the seismic liquefaction assessment field by providing a structured,adaptable methodology for accurate and reliable analysis.
基金Scientific Research Fund of Institute of Engineering Mechanics,China Earthquake Administration under Grant No.2024A03。
文摘On March 28,2025,a catastrophic M 7.9 earthquake shook central Myanmar,causing extensive damage to buildings,significant casualties,and substantial economic loss,making it one of the most severe natural disasters Myanmar has faced in recent years.During an on-site investigation that lasted two weeks,widely spreading liquefaction phenomena and associated damage to buildings and other facilities were investigated in 16 villages or districts in the seismic zones,involving hundreds of residential houses,two large bridges,underground storage tanks,etc.Ground fissures generated by liquefaction tore apart houses,which contributed to a significant impact on house damage.The loss of ground bearing capacity is another impact of liquefaction with regard to structural damage,causing the subsidence and tilting of houses.Several consequences of liquefaction were identified,such as lateral spreading,which demolishes houses and causes casualties,as well as damage to two large bridges as a result of lateral spreading.The cases of liquefaction following the Myanmar earthquake reported on herein provide data and lessons for future seismic desigs to help prevent such disasters in Southeast Asia.Through analyzing the phenomena and characteristics of soil liquefaction,the methods and techniques for liquefaction hazard mitigation in other countries also can be improved.
基金National Natural Science Foundation of China under Grant No.U21A20164National Science Fund for Distinguished Young Scholars of China under Grant No.51825904。
文摘Seismic-induced liquefaction of sandy soils can fail foundations in the vicinity of buildings.To investigate the effect of a non-free field subsurface seismic history on the ability of saturated sandy soils to resist liquefaction,four shaking events with different accelerations were input to the sandy soils in the non-free-field.The results of the study revealed that:(1)Shallow soils that are not free-field undergo acceleration amplification effects after being subjected to seismic loading.(2)Building overburden pressure reduces the sensitivity of the shallow soils directly below in small and moderate earthquakes,which are more prone to rearranging and forming unstable structures under strong seismic effects.The excess pore pressure response on the load side resembles that of a free site,with the depth range of the liquefaction strength of soils affected by the seismic history,increasing progressively as input seismic intensity increases.(3)After experiencing earthquakes of different intensities,the excess pore pressure directly below the building overburden pressure at 0.1 m and 0.2 m is greater than that at the side.At the same time,the side of the building structure is more prone to liquefaction than the soil directly below it.
文摘Liquefaction is one of the prominent factors leading to damage to soil and structures.In this study,the rela-tionship between liquefaction potential and soil parameters is determined by applying feature importance methods to Random Forest(RF),Logistic Regression(LR),Multilayer Perceptron(MLP),Support Vector Machine(SVM)and eXtreme Gradient Boosting(XGBoost)algorithms.Feature importance methods consist of permuta-tion and Shapley Additive exPlanations(SHAP)importances along with the used model’s built-in feature importance method if it exists.These suggested approaches incorporate an extensive dataset of geotechnical parameters,historical liquefaction events,and soil properties.The feature set comprises 18 parameters that are gathered from 161 field cases.Algorithms are used to determine the optimum performance feature set.Compared to other approaches,the study assesses how well these algorithms predict soil liquefaction potential.Early findings show that the algorithms perform well,demonstrating their capacity to identify non-linear connections and improve prediction accuracy.Among the feature set,σ,v(psf),MSF,CSRσ,v,FC%,Vs*,40f t(f ps)and N1,60,CS are the ones that have the highest deterministic power on the result.The study’s contribution is that,in the absence of extensive data for liquefaction assessment,the proposed method estimates the liquefaction potential using five parameters with promising accuracy.
基金National Natural Science Foundation of China (No. 22208273)Tianchi Talent Plan of Xinjiang Uygur Autonomous RegionPostdoctoral Fellowship Program of CPSF under Grant Number GZC20240428。
文摘Coal direct liquefaction technology is a crucial contemporary coal chemical technology for efficient and clean use of coal resources. The development of direct coal liquefaction technology and the promotion of alternative energy sources are important measures to guarantee energy security and economic security. However, several challenges need to be addressed, including low conversion rate, inadequate oil yield, significant coking, demanding reaction conditions, and high energy consumption. Extensive research has been conducted on these issues, but further exploration is required in certain aspects such as pyrolysis of macromolecules during the liquefaction process, hydrogen activation, catalysts' performance and stability, solvent hydrogenation, as well as interactions between free radicals to understand their mechanisms better. This paper presents a comprehensive analysis of the design strategy for efficient catalysts in coal liquefaction, encompassing the mechanism of coal liquefaction, catalyst construction,and enhancement of catalytic conversion efficiency. It serves as a comprehensive guide for further research endeavors. Firstly, it systematically summarizes the conversion mechanism of direct coal liquefaction, provides detailed descriptions of various catalyst design strategies, and especially outlines the catalytic mechanism. Furthermore, it addresses the challenges and prospects associated with constructing efficient catalysts for direct coal liquefaction based on an understanding of their action mechanisms.
基金supported by the National Natural Science Foundation of China,China(No.52474088).
文摘Liquid hydrogen has attracted much attention due to its high energy storage density and suitability for long-distance transportation.An efficient hydrogen liquefaction process is the key to obtaining liquid hydrogen.In an effort to determine the parameter optimization of the hydrogen liquefaction process,this paper employed process simulation software Aspen HYSYS to simulate the hydrogen liquefaction process.By establishing a dynamic model of the unit module,this study carried out dynamic simulation optimization based on the steady-state process and process parameters of the hydrogen liquefaction process and analyzed the dynamic characteristics of the process.Based on the pressure drop characteristic experiment,an equation for the pressure drop in the heat exchanger was proposed.The heat transfer of hydrogen conversion was simulated and analyzed,and its accuracy was verified by comparison with the literature.The dynamic simulation of a plate-fin heat exchanger was carried out by coupling heat transfer simulation and the pressure drop experiment.The results show that the increase in inlet temperature(5℃and 10℃)leads to an increase in specific energy consumption(0.65%and 1.29%,respectively)and a decrease in hydrogen liquefaction rate(0.63%and 2.88%,respectively).When the inlet pressure decreases by 28.57%,the hydrogen temperature of the whole liquefaction process decreases and the specific energy consumption increases by 52.94%.The research results are of great significance for improving the operating efficiency of the refrigeration cycle and guiding the actual liquid hydrogen production.
基金funded by the Basic Research program from the Institute of Earthquake Forecasting,China Earthquake Administration(Grant No.CEAIEF20240302)the National Natural Science Foundation of China(Grant Nos.42072248)the National Key Research and Development Program of China(Grant Nos.2021YFC3000600 and 2019YFE0108900)。
文摘Rapidly obtaining spatial distribution maps of secondary disasters triggered by strong earthquakes is crucial for understanding the disaster-causing processes in the earthquake hazard chain and formulating effective emergency response measures and post-disaster reconstruction plans.On April 3,2024,a M_(W)7.4 earthquake struck offshore east of Hualien,Taiwan,China,which triggered numerous coseismic landslides in bedrock mountain regions and severe soil liquefaction in coastal areas,resulting in significant economic losses.This study utilized postearthquake emergency data from China's high-resolution optical satellite imagery and applied visual interpretation method to establish a partial database of secondary disasters triggered by the 2024 Hualien earthquake.A total of 5348 coseismic landslides were identified,which were primarily distributed along the eastern slopes of the Central Mountain Range watersheds.In high mountain valleys,these landslides mainly manifest as localized bedrock collapses or slope debris flows,causing extensive damage to highways and tourism facilities.Their distribution partially overlaps with the landslide concentration zones triggered by the 1999 Chi-Chi earthquake.Additionally,6040 soil liquefaction events were interpreted,predominantly in the Hualien Port area and the lowland valleys of the Hualien River and concentrated within the IX-intensity zone.Widespread surface subsidence and sand ejections characterized soil liquefaction.Verified against local field investigation data in Taiwan,rapid imaging through post-earthquake remote sensing data can effectively assess the distribution of coseismic landslides and soil liquefaction within high-intensity zones.This study provides efficient and reliable data for earthquake disaster response.Moreover,the results are critical for seismic disaster mitigation in high mountain valleys and coastal lowlands.
文摘By means of X ray and gas chromatography analysis, the crystalline structure of untreated wood , alkali treated wood and benzylated wood and their liquefaction in toluene and tetrahydrofufan with HCl as a catalyst were studied .The upper solution of benzylated wood was also studied by GC MS analysis. It proved that the introduction of bulky benzyl group in wood significantly changed the crystalline structure of wood ,enlarging the free volume which facilitated the penetration of solvent into the matrix of treated wood, thus tremendously enhancing thesolubility in solvent,compared to untreated wood and alkali treated wood. The percentage of residue decreased and the combined solvent increased with the increase of weight gain revealed that the liquefaction process became easy. Furthermore, the factors that influenced the liquefaction of benzylated wood were investigated. It showed that the liquefaction performance was improved with the increase of liquefaction time and the amount of catalyst when toluene was used as a solvent, especially in the presence of THF as solvent, there existed the optimum liquefaction time and the amount of catalyst .
基金Supported by the National Engineering Labo-ratory of Direct Coal Liquefaction(MZY-16).
文摘In this research,molecular structure models were developed respectively for Shenhua coal vitrinite concentrates(SDV)and inertinite concentrates(SDI),on the basis of information on constitutional unit of Shenhau coal and elemental analysis results obtained from^(13)C-NMR analysis characterization,FTIR analysis characterization,X-ray diffraction XRD and XPS analysis characterization.It can be observed from characterization data and molecular structure models that the structure of SDV and SDI is dominated by aromatic hydrocarbon,with aromaticity of SDI higher than that of SDV;SDV mainly consists of small molecule basic structure unit,while SDI is largely made from macromolecular structure unit.Based on bond-level parameters of the molecular model,the research found through the autoclave experiment that vitrinite liquefaction process goes under thermodynamics control and inertinite liquefaction process under dynamics control.The research developed an efficient directional direct coal liquefaction technology based on the maceral characteristics of Shenhua coal,which can effectively improve oil yield and lower gas yield.
基金Supported by the Key Research Program Foundation of Ministry of Education of China (Grant No.02021) and the Development Plan Foundation of Beijing Forestry University
文摘To clarify the influencing factors of liquefaction of wood in phenol using phosphoric acid as a catalyst and get its liquefaction technology, a study on the liquefaction technology of Chinese fir (Cunninghamia lanceolata) and poplar (triploid Populus tomentosa Carr) under different conditions was conducted. The results indicate that the residue rate decreases with the increase of liquefaction temperature, liquefaction time, catalyst content or liquid ratio. It is also found that the optimum condition of liquefaction for poplar is estimated as: the reaction temperature of 180 C, the reaction time of 2.5 h, liquid ratio (phenol/wood ratio) of 4.5 and catalyst content of 8%, and 4.2% residue rate could be obtained. Under the processing parameters of temperature 180 C, the reaction time of 2.5 h, liquid ratio (phenol/wood ratio) of 4 and catalyst content of 10%, the residue rate of Chinese fir can reach 5.6%.
基金financially supported by the National Natural Science Foundation of China (Grant No.41761144077)the CAS “Light of West China” Program (Grant No.Y6R2240240)+1 种基金the Key Research Program of Frontier Sciences,CAS (Grant No.QYZDB-SSW-DQC010)the Sichuan science and technology plan project (Grant No.2017JY0251)
文摘Quaternary silt is widely distributed in China and easily liquefies during earthquakes. To identify the influence of the dry density on the liquefaction behaviour of Quaternary silt, 40 cyclic triaxial liquefaction tests were performed on loose silt(dry density rd=1.460 g/cm^3) and dense silt(rd=1.586 g/cm^3) under different cyclic stress ratios(CSRs) to obtain liquefaction assessment criteria, determine the liquefaction resistance, improve the excess pore water pressure(EPWP) growth model and clarify the relationship between the shear modulus and damping ratio. The results indicate that the initial liquefaction assessment criteria for the loose and dense silts are a double-amplitude axial strain of 5% and an EPWP ratio of 1. The increase in the anti-liquefaction ability for the dense silt is more significant under lower confining pressures. The CSR of loose silt falls well within the results of the sandy silt and Fraser River silt, and the dense silt exhibits a higher liquefaction resistance than the sand-silt mixture. The relationships between the CSR and loading cycles were obtained at a failure strain of 1%. The EPWP development in the dense and loose silts complies with the "fast-stable" and "fast-gentle-sharp" growth modes, respectively. The power function model can effectively describe the EPWP growth characteristics of the dense silt. Finally, based on the liquefaction behaviour of silt, a suggestion for reinforcing silt slopes or foundations is proposed.
基金financially supported by the National Key Research and Development Program of China(Grant Nos.2021YFB2600700 and 2022YFC3102302)the Central Public-Interest Scientific Institution Basal Research Fund(Grant No.Y221007)+2 种基金the National Natural Science Foundation of China(Grant No.52271274)the Key Laboratory of Ministry of Education for Coastal Disaster and Protection,Hohai University(Grant No.202205)the Key Project of NSFC-Shandong Joint Research Funding POW3C(Grant No.U1906230).
文摘The nonlinear variation of wave is commonly seen in nearshore area,and the resulting seabed response and liquefaction are of high concern to coastal engineers.In this study,an analytical formula considering the nonlinear wave skewness and asymmetry is adopted to provide wave pressure on the seabed surface.The liquefaction depth attenuation coefficient and width growth coefficient are defined to quantitatively characterize the nonlinear effect of wave on seabed liquefaction.Based on the 2D full dynamic model of wave-induced seabed response,a detailed parametric study is carried out in order to evaluate the influence of the nonlinear variation of wave loadings on seabed liquefaction.Further,new empirical prediction formulas are proposed to fast predict the maximum liquefaction under nonlinear wave.Results indicate that(1)Due to the influence of wave nonlinearity,the vertical transmission of negative pore water pressure in the seabed is hindered,and therefore,the amplitude decreases significantly.(2)In general,with the increase of wave nonlinearity,the liquefaction depth of seabed decreases gradually.Especially under asymmetric and skewed wave loading,the attenuation of maximum seabed liquefaction depth is the most significant among all the nonlinear wave conditions.However,highly skewed wave can cause the liquefaction depth of seabed greater than that under linear wave.(3)The asymmetry of wave pressure leads to the increase of liquefaction width,whereas the influence of skewedness is not significant.(4)Compared with the nonlinear waveform,seabed liquefaction is more sensitive to the variation of nonlinear degree of wave loading.
基金the financial support from the National Key Research and Development Program of China(2022YFB4101302-01)the National Natural Science Foundation of China(22178243)the science and technology innovation project of China Shenhua Coal to Liquid and Chemical Company Limited(MZYHG-22–02).
文摘The cyclic hydrogenation technology in a direct coal liquefaction process relies on the dissolved hydrogen of the solvent or oil participating in the hydrogenation reaction.Thus,a theoretical basis for process optimization and reactor design can be established by analyzing the solubility of hydrogen in liquefaction solvents.Experimental studies of hydrogen solubility in liquefaction solvents are challenging due to harsh reaction conditions and complex solvent compositions.In this study,the composition and content of liquefied solvents were analyzed.As model compounds,hexadecane,toluene,naphthalene,tetrahydronaphthalene,and phenanthrene were chosen to represent the liquefied solvents in chain alkanes and monocyclic,bicyclic,and tricyclic aromatic hydrocarbons.The solubility of hydrogen X(mol/mol)in pure solvent components and mixed solvents(alkanes and aromatics mixed in proportion to the chain alkanes+bicyclic aromatic hydrocarbons,bicyclic saturated aromatic hydrocarbons+bicyclic aromatic hydrocarbons,and bicyclic aromatic hydrocarbons+compounds containing het-eroatoms composed of mixed components)are determined using Aspen simulation at temperature and pressure conditions of 373–523 K and 2–10 MPa.The results demonstrated that at high temperatures and pressures,the solubility of hydrogen in the solvent increases with the increase in temperature and pressure,with the pressure having a greater impact.Further-more,the results revealed that hydrogen is more soluble in straight-chain alkanes than in other solvents,and the solubility of eicosanoids reaches a maximum of 0.296.The hydrogen solubility in aromatic ring compounds decreased gradually with an increase in the aromatic ring number.The influence of chain alkanes on the solubility of hydrogen predominates in a mixture of solvents with different mixing ratios of chain alkanes and aromatic hydrocarbons.The solubility of hydrogen in mixed aromatic solvents is less than that in the corresponding single solvents.Hydrogen is less soluble in solvent compounds containing heteroatoms than in compounds without heteroatoms.
基金Supported by Project of Beijing Municipal Science and Technology Commission(Z07090500550704)the Key Scientific and Technological Project of Henan Province(102102210447)~~
文摘[Objective]This paper aimed at studying the liquefaction technology of chestnut shells [Method]Effects on chestnut shells liquefaction of six catalysts were studied,which were sodium hydroxide,sodium carbonate,acetic acid（99.5%）,phosphoric acid（85%）,hydrochloric acid（37%）,sulfuric acid（98%）.The research had analyzed the liquefaction effects of chestnut shells in presence of phenol and at liquefaction temperatures of 130,150 and 170 ℃,in which the proportion of added quantities of concentrated sulfuric acid,phosphoric acid,concentrated hydrochloric acid to phenol were 1%-6%.Properties of phenolic resin made from formaldehyde and phenol-liquefied products of chestnut shells catalyzed by concentrated sulfuric acid with an added amount of 4% at 150 ℃（WPF）were analyzed and compared with traditional phenolic formaldehyde resin（PF）.[Result]Acid catalysts were better than alkaline ones in the phenol-liquefaction of chestnut shells,and the liquefaction ratio increased with the increasing of acidic intensity.The liquefaction ratio had attained the maximum as 92.11 % when catalyzed by concentrated sulfuric acid with an added amount of 4% at 150 ℃.The phenolic resin made from the liquefied products of chestnut shells was basically in accordance with the standard of GB/T 14732-93 when the mass ratio of chestnut shells powders to phenol was 1∶3.[Conclusion]It was possible to produce phenolic resin with liquefied chestnut shells.
基金financial support from the Doctoral Innovative Talent Cultivation Fund at China University of Mining and Technology (Beijing)(No. BBJ2023049)。
文摘Earthquakes can cause violent liquefaction of the soil, resulting in unstable foundations that can cause serious damage to facilities such as buildings, roads, and dikes. This is a primary cause of major earthquake disasters. Therefore, the discrimination and prediction of earthquake-induced soil liquefaction has been a hot issue in geohazard research. The soil liquefaction assessment is an integral part of engineering practice. This paper evaluated a dataset of 435 seismic sand liquefaction events using machine learning algorithms. The dataset was analyzed using seven potential assessment parameters. Ten machine learning algorithms are evaluated for their ability to assess seismic sand liquefaction potential, including Linear Discriminant Analysis(LDA), Quadratic Discriminant Analysis(QDA), Naive Bayes(NB), KNearest Neighbor(KNN), Artificial Neural Network(ANN), Classification Tree(CT), Support Vector Machine(SVM), Random Forest(RF), e Xtreme Gradient Boosting(XGBoost), Light Gradient Boosting Machine(Light GBM). A 10-fold cross-validation(CV) method was used in the modeling process to verify the predictive performance of the machine learning models. The final percentages of significant parameters that influenced the prediction results were obtained as Cyclic Stress Ratio(CSR) and Shear-Wave Velocity( VS1) with 56% and 38%, respectively. The final machine learning algorithms identified as suitable for seismic sand liquefaction assessment were the CT, RF, XGBoost algorithms, with the RF algorithm performing best.
基金Project(5141001028)supported by International Cooperation and Exchanges of NSFC,ChinaProjects(51308566,51308565,51409025)supported by the National Natural Science Foundation of ChinaProject(CDJZR12200002)supported by the Fundamental Research Funds for the Central Universities,China
文摘This work investigates the correlation between a large number of widely used ground motion intensity measures(IMs) and the corresponding liquefaction potential of a soil deposit during earthquake loading. In order to accomplish this purpose the seismic responses of 32 sloping liquefiable site models consisting of layered cohesionless soil were subjected to 139 earthquake ground motions. Two sets of ground motions, consisting of 80 ordinary records and 59 pulse-like near-fault records are used in the dynamic analyses. The liquefaction potential of the site is expressed in terms of the the mean pore pressure ratio, the maximum ground settlement, the maximum ground horizontal displacement and the maximum ground horizontal acceleration. For each individual accelerogram, the values of the aforementioned liquefaction potential measures are determined. Then, the correlation between the liquefaction potential measures and the IMs is evaluated. The results reveal that the velocity spectrum intensity(VSI) shows the strongest correlation with the liquefaction potential of sloping site. VSI is also proven to be a sufficient intensity measure with respect to earthquake magnitude and source-to-site distance, and has a good predictability, thus making it a prime candidate for the seismic liquefaction hazard evaluation.
