While stromal interactions are essential in cancer adaptation to hormonal therapies,the effects of bone stroma and androgen deprivation on cancer progression in bone are poorly understood.Here,we tissue-engineered and...While stromal interactions are essential in cancer adaptation to hormonal therapies,the effects of bone stroma and androgen deprivation on cancer progression in bone are poorly understood.Here,we tissue-engineered and validated an in vitro microtissue model of osteoblastic bone metastases,and used it to study the effects of androgen deprivation in this microenvironment.The model was established by culturing primary human osteoprogenitor cells on melt electrowritten polymer scaffolds,leading to a mineralized osteoblast-derived microtissue containing,in a 3D setting,viable osteoblastic cells,osteocytic cells,and appropriate expression of osteoblast/osteocyte-derived mRNA and proteins,and mineral content.Direct co-culture of androgen receptordependent/ independent cell lines (LNCaP,C4-2B,and PC3) led cancer cells to display functional and molecular features as observed in vivo.Co-cultured cancer cells showed increased affinity to the microtissues,as a function of their bone metastatic potential.Cocultures led to alkaline phosphatase and collagen-I upregulation and sclerostin downregulation,consistent with the clinical marker profile of osteoblastic bone metastases.LNCaP showed a significant adaptive response under androgen deprivation in the microtissues,with the notable appearance of neuroendocrine transdifferentiation features and increased expression of related markers (dopa decarboxylase,enolase 2).Androgen deprivation affected the biology of the metastatic microenvironment with stronger upregulation of androgen receptor,alkaline phosphatase,and dopa decarboxylase,as seen in the transition towards resistance.The unique microtissues engineered here represent a substantial asset to determine the involvement of the human bone microenvironment in prostate cancer progression and response to a therapeutic context in this microenvironment.展开更多
A high humidity-resistant,dual mechanical responsive,and reversible mechanochromic wrinkling system based on a VHB 4910-polydimethylsiloxane(PDMS)substrate with a thin film consisting of 90 wt%poly(vinyl butyral)(PVB)...A high humidity-resistant,dual mechanical responsive,and reversible mechanochromic wrinkling system based on a VHB 4910-polydimethylsiloxane(PDMS)substrate with a thin film consisting of 90 wt%poly(vinyl butyral)(PVB)and 10 wt%hydroxypropyl cellulose(HPC)has been reported.The wrinkling system exhibited significant optical tuning from transparent to opaque states with 50%changes in transmittance,which was achieved through the dual mechanical modes of pre-stretching and releasing processes or bending.Upon exposure to ethanol vapor or a re-flattening process,wrinkles can be erased,yielding a transparent state.Consequently,the wrinkling system could be reversibly switched between transparency and opacity for 1000 cycles with marginal changes in the optical performance.Owing to the insolubility of PVB in water,the wrinkling patterns exhibited excellent durability in high-humidity environments(relative humidity(RH)=99%).Furthermore,the smart encryption device is also demonstrated via mechano-controlled surface topography by patterning the wrinkling system,suggesting potential applications of the designed structure in smart windows,anti-counterfeiting,dynamic display,optical information encryption,and rewritable surfaces.展开更多
Accurate estimation of evapotranspiration(ET)is crucial for efficient water resource management,particularly in the face of climate change and increasing water scarcity.This study performs a bibliometric analysis of 3...Accurate estimation of evapotranspiration(ET)is crucial for efficient water resource management,particularly in the face of climate change and increasing water scarcity.This study performs a bibliometric analysis of 352 articles and a systematic review of 35 peer-reviewed papers,selected according to PRISMA guidelines,to evaluate the performance of Hybrid Artificial Neural Networks(HANNs)in ET estimation.The findings demonstrate that HANNs,particularly those combining Multilayer Perceptrons(MLPs),Recurrent Neural Networks(RNNs),and Convolutional Neural Networks(CNNs),are highly effective in capturing the complex nonlinear relationships and tem-poral dependencies characteristic of hydrological processes.These hybrid models,often integrated with optimization algorithms and fuzzy logic frameworks,significantly improve the predictive accuracy and generalization capabilities of ET estimation.The growing adoption of advanced evaluation metrics,such as Kling-Gupta Efficiency(KGE)and Taylor Diagrams,highlights the increasing demand for more robust performance assessments beyond traditional methods.Despite the promising results,challenges remain,particularly regarding model interpretability,computational efficiency,and data scarcity.Future research should prioritize the integration of interpretability techniques,such as attention mechanisms,Local Interpretable Model-Agnostic Explanations(LIME),and feature importance analysis,to enhance model transparency and foster stakeholder trust.Additionally,improving HANN models’scalability and computational efficiency is crucial,especially for large-scale,real-world applications.Approaches such as transfer learning,parallel processing,and hyperparameter optimization will be essential in overcoming these challenges.This study underscores the transformative potential of HANN models for precise ET estimation,particularly in water-scarce and climate-vulnerable regions.By integrating CNNs for automatic feature extraction and leveraging hybrid architectures,HANNs offer considerable advantages for optimizing water management,particularly agriculture.Addressing challenges related to interpretability and scalability will be vital to ensuring the widespread deployment and operational success of HANNs in global water resource management.展开更多
The corrosion behavior of the laser powder bed fusion(LPBF)AZ91 magnesium alloy was investigated by comparing its longitudinal and transverse sections with the cast AZ91 alloy.Microstructural analysis revealed a fine,...The corrosion behavior of the laser powder bed fusion(LPBF)AZ91 magnesium alloy was investigated by comparing its longitudinal and transverse sections with the cast AZ91 alloy.Microstructural analysis revealed a fine,homogeneous Mg_(17)Al_(12) distribution in LPBF samples,contrasting with the network-like structure in the cast alloy.Electrochemical and hydrogen evolution tests demonstrated no significant anisotropy in LPBF sections,but they exhibited higher corrosion rates than the cast alloy.Potentiodynamic polarization and electrochemical impedance spectroscopy confirmed that the corrosion process was cathodically controlled by the Mg_(17)Al_(12) phase fraction.Scanning vibrating electrode technique further validated these findings,highlighting lower electrochemical activity in cast AZ91 alloy.展开更多
The structural phase transitions and ferroelectric dynamics of lead-free AgNbO_(3)have attracted consid-erable attention owing to their potential in energy-storage device applications.Here,we examine the impact of Li+...The structural phase transitions and ferroelectric dynamics of lead-free AgNbO_(3)have attracted consid-erable attention owing to their potential in energy-storage device applications.Here,we examine the impact of Li+doping on the phase transitions and polarization behavior of(Ag_(1-x)Li_(x))NbO_(3)(x=0-7%)ceramics through comprehensive dielectric and ferroelectric analyses.Rietveld refinement reveals a Li+-induced phase transition from Pbcm to R3c,with x=5%and x=6%compositions near the morphotropic phase boundary(MPB).Dielectric anomalies identify key characteristic temperatures,supporting the con-struction of a low-field phase diagram.High-field studies uncover a direct relationship between phase structure and polarization behavior,culminating in a high-field phase diagram.Near-MPB compositions exhibit distinct structural states,elucidating the mechanisms of reversible and irreversible phase transi-tions.This work provides a comprehensive explanation of the evolution of hysteresis loop profiles,capturing their progression from double hysteresis loops to square loops and their subsequent reversion to double loops under varying electric field and temperature conditions.These temperature-composition(T-x)and temperature-electric field(T-E)phase diagrams provide a robust framework for understanding phase evolution,offering critical insights into optimizing AgNbO_(3)-based ceramics for advanced functional applications.展开更多
Accurate capacity and State of Charge(SOC)estimation are crucial for ensuring the safety and longevity of lithium-ion batteries in electric vehicles.This study examines ten machine learning architectures,Including Dee...Accurate capacity and State of Charge(SOC)estimation are crucial for ensuring the safety and longevity of lithium-ion batteries in electric vehicles.This study examines ten machine learning architectures,Including Deep Belief Network(DBN),Bidirectional Recurrent Neural Network(BiDirRNN),Gated Recurrent Unit(GRU),and others using the NASA B0005 dataset of 591,458 instances.Results indicate that DBN excels in capacity estimation,achieving orders-of-magnitude lower error values and explaining over 99.97%of the predicted variable’s variance.When computational efficiency is paramount,the Deep Neural Network(DNN)offers a strong alternative,delivering near-competitive accuracy with significantly reduced prediction times.The GRU achieves the best overall performance for SOC estimation,attaining an R^(2) of 0.9999,while the BiDirRNN provides a marginally lower error at a slightly higher computational speed.In contrast,Convolutional Neural Networks(CNN)and Radial Basis Function Networks(RBFN)exhibit relatively high error rates,making them less viable for real-world battery management.Analyses of error distributions reveal that the top-performing models cluster most predictions within tight bounds,limiting the risk of overcharging or deep discharging.These findings highlight the trade-off between accuracy and computational overhead,offering valuable guidance for battery management system(BMS)designers seeking optimal performance under constrained resources.Future work may further explore advanced data augmentation and domain adaptation techniques to enhance these models’robustness in diverse operating conditions.展开更多
Boron suboxide(B_(6)O)is recognized as a superhard material with a low mass density,high resistance to chemical wear,and excellent wear resistance.Despite its desirable properties,the limited fracture tough-ness of B_...Boron suboxide(B_(6)O)is recognized as a superhard material with a low mass density,high resistance to chemical wear,and excellent wear resistance.Despite its desirable properties,the limited fracture tough-ness of B_(6)O restricts its application in industrial contexts.This study presents the structural and me-chanical characterization of B_(6)O-SiC nanocomposites,which were synthesized via a high-pressure high-temperature sintering process of B_(6)O powders and SiC whiskers.The sintering process induced fragmen-tation of SiC whiskers,resulting in the homogenous distribution of SiC fragments within the B_(6)O matrix.An increase in SiC content was observed to decrease the composite’s hardness,while initially reducing then enhancing its toughness.The nanocomposites containing 20 wt%and 30 wt%SiC whiskers exhibited significant improvements in fracture toughness,averaging 6.5 MPa m^(1/2)and 7.0 MPa m^(1/2),respectively-approximately threefold the toughness of polycrystalline B_(6)O-while sustaining high hardness values of 36.3 GPa and 35.6 GPa on average.Microstructural analyses revealed that the composites’superior me-chanical performance is due to the presence of strong grain boundaries,as well as a high density of nan-otwins and stacking faults.The findings demonstrate a viable method for producing B_(6)O-based nanocom-posites with enhanced hardness and toughness,potentially expanding their industrial applicability.展开更多
Protecting Supervisory Control and Data Acquisition-Industrial Internet of Things(SCADA-IIoT)systems against intruders has become essential since industrial control systems now oversee critical infrastructure,and cybe...Protecting Supervisory Control and Data Acquisition-Industrial Internet of Things(SCADA-IIoT)systems against intruders has become essential since industrial control systems now oversee critical infrastructure,and cyber attackers more frequently target these systems.Due to their connection of physical assets with digital networks,SCADA-IIoT systems face substantial risks from multiple attack types,including Distributed Denial of Service(DDoS),spoofing,and more advanced intrusion methods.Previous research in this field faces challenges due to insufficient solutions,as current intrusion detection systems lack the necessary accuracy,scalability,and adaptability needed for IIoT environments.This paper introduces CyberFortis,a novel cybersecurity framework aimed at detecting and preventing cyber threats in SCADA-IIoT systems.CyberFortis presents two key innovations:Firstly,Siamese Double Deep Q-Network with Autoencoders(Siamdqn-AE)FusionNet,which enhances intrusion detection by combining deep Q-Networks with autoencoders for improved attack detection and feature extraction;and secondly,the PopHydra Optimiser,an innovative solution to compute reinforcement learning discount factors for better model performance and convergence.This method combines Siamese deep Q-Networks with autoencoders to create a system that can detect different types of attacks more effectively and adapt to new challenges.CyberFortis is better than current top attack detection systems,showing higher scores in important areas like accuracy,precision,recall,and F1-score,based on data from CICIoT 2023,UNSW-NB 15,and WUSTL-IIoT datasets.Results from the proposed framework show a 97.5%accuracy rate,indicating its potential as an effective solution for SCADA-IIoT cybersecurity against emerging threats.The research confirms that the proposed security and resilience methods are successful in protecting vital industrial control systems within their operational environments.展开更多
This study focused on leaching behavior of alkaline anion and sodium in bauxite residue through ammonium chloride treatment.The results showed that the pH of bauxite residue decreased from 10.49 to 8.93,total alkaline...This study focused on leaching behavior of alkaline anion and sodium in bauxite residue through ammonium chloride treatment.The results showed that the pH of bauxite residue decreased from 10.49 to 8.93,total alkaline anion(HCO3^-,CO3^2-,OH^-,AlO2^-)concentration reduced from 38.89 to 25.50 mmol/L,leaching rate of soluble sodium was 80.86%with ammonium chloride addition of 0.75%,liquid/solid(L/S)ratio of 3(mL/g),temperature of 30°C and reaction time of 18 h;L/S ratio was the main factor affecting the removal of alkaline anion and the leaching of sodium.Furthermore,ammonium chloride promoted the dissolution of diaspore and changed the micro/morphological characteristics with the increase of massive structure.The findings of this work will contribute to achieve soil-formation of bauxite residue.展开更多
This study has evaluated the effect of different levels of cold rolling（from 0 to 50%）on the microstructural,magnetic,and mechanical properties and the corrosion behavior of 316L austenitic stainless steel in Na Cl...This study has evaluated the effect of different levels of cold rolling（from 0 to 50%）on the microstructural,magnetic,and mechanical properties and the corrosion behavior of 316L austenitic stainless steel in Na Cl（1 mol/L）＋H_2SO_4（0.5 mol/L）solution.Microstructural examinations using optical microscopy revealed the development of a morphological texture from coaxial to elongated grains during the cold-rolling process.Phase analysis carried out on the basis of X-ray diffraction confirmed the formation of the ferromagneticα′-martensite phase under the stresses applied during cold rolling.This finding is in agreement with magnetic measurements using a vibrating sample magnetometer.Mechanical properties determined by tensile and Vickers microhardness tests demonstrated an upward trend in the hardness-to-yield strength ratio with increasing cold-rolling percentage,representing a reduction in the material’s work-hardening ability.Uniform and localized corrosion parameters were estimated via potentiodynamic polarization corrosion tests and electrochemical impedance spectroscopy.In contrast to the uniform corrosion,wherein the corrosion current density increased with increasing cold-working degree because of the high density of microstructural defects,the passive potential range and breakdown potential increased by cold working,showing greater resistance to pit nucleation.Although pits were formed,the cold-rolled material repassivation tendency decreased because of the broader hysteresis anodic loop,as confirmed experimentally by observation of the microscopic features after electrochemical cyclic polarization evaluations.展开更多
This study revealed the relationship between the presence of calcium impurities and ammoniacal nitrogen concentration upon crystallization of struvite.The research hypothesis was that the presence of both calcium and ...This study revealed the relationship between the presence of calcium impurities and ammoniacal nitrogen concentration upon crystallization of struvite.The research hypothesis was that the presence of both calcium and high concentrations of ammoniacal nitrogen(328–1000 mg/L)in waste activated sludge may influence the struvite quality and acid stability.Hence,we studied the impact of Ca:Mg ratio upon morphology,particle size,purity and dissolution of struvite,in the presence of varying levels of excess ammoniacal nitrogen.X-ray diffraction revealed that up to 31.4%amorphous material was made which was assigned to hydroxyapatite.Increasing the ammoniacal nitrogen concentration and elevation of the Mg:Ca ratio maximized the presence of struvite.Struvite particle size was also increased by ammoniacal nitrogen as was twinning of the crystals.Tests with dilute solutions of organic acid revealed the sensitivity of struvite dissolution to the physical characteristics of the struvite.Smaller particles(21.2μm)dissolved at higher rates than larger particles(35.86μm).However,struvite dissolved rapidly as the p H was further reduced irrespective of the physical characteristics.Therefore,addition of struvite to low p H soils was not viewed as beneficial in terms of controlled nutrient release.Overall,this study revealed that waste activated sludge effluent with high ammoniacal nitrogen was prospective for synthesis of high quality struvite material.展开更多
A low-alloy gray cast iron containing hard carbide-forming elements, such as vanadium and chromium, was cast by sand mould casting. Its wear resistance was compared with that of an untreated gray cast iron. Three diff...A low-alloy gray cast iron containing hard carbide-forming elements, such as vanadium and chromium, was cast by sand mould casting. Its wear resistance was compared with that of an untreated gray cast iron. Three different loading conditions were tested under a con- stant speed. It was observed that this alloy could reduce the wear loss of standard gray cast iron by up to 89%, which was much greater than what was achieved in previous reports. Scanning electron microscopy （SEM） was used to determine the predominant wear mechanism of both the alloys. In a mild wear regime, the oxidative mechanism was predominant; however, in a severe wear regime, this mechanism was not predominant and the adhesive mechanism was involved. EDX analysis was conducted to evaluate the quantitative amounts of elements in the tribochemical films formed on the wear tracks.展开更多
The influence of combination of different designated precipitation hardening and cold working on the tensile properties of 6061 aluminum alloy was investigated. The results indicate that applying single aging at 180 ...The influence of combination of different designated precipitation hardening and cold working on the tensile properties of 6061 aluminum alloy was investigated. The results indicate that applying single aging at 180 ℃ for 4 h in different thermal-mechanical treatments improves both the strength and elongation. However, double aging does not improve the mechanical properties. In addition, pre-aging shows a negative effect on the subsequent precipitation hardening of material. The changes in mechanical properties were discussed by explanation of microstructural evolution due to the competition of precipitation hardening, strain hardening and work softening processes.展开更多
Compression index Ccis an essential parameter in geotechnical design for which the effectiveness of correlation is still a challenge.This paper suggests a novel modelling approach using machine learning(ML)technique.T...Compression index Ccis an essential parameter in geotechnical design for which the effectiveness of correlation is still a challenge.This paper suggests a novel modelling approach using machine learning(ML)technique.The performance of five commonly used machine learning(ML)algorithms,i.e.back-propagation neural network(BPNN),extreme learning machine(ELM),support vector machine(SVM),random forest(RF)and evolutionary polynomial regression(EPR)in predicting Cc is comprehensively investigated.A database with a total number of 311 datasets including three input variables,i.e.initial void ratio e0,liquid limit water content wL,plasticity index Ip,and one output variable Cc is first established.Genetic algorithm(GA)is used to optimize the hyper-parameters in five ML algorithms,and the average prediction error for the 10-fold cross-validation(CV)sets is set as thefitness function in the GA for enhancing the robustness of ML models.The results indicate that ML models outperform empirical prediction formulations with lower prediction error.RF yields the lowest error followed by BPNN,ELM,EPR and SVM.If the ranges of input variables in the database are large enough,BPNN and RF models are recommended to predict Cc.Furthermore,if the distribution of input variables is continuous,RF model is the best one.Otherwise,EPR model is recommended if the ranges of input variables are small.The predicted correlations between input and output variables using five ML models show great agreement with the physical explanation.展开更多
The Mg-6Al-4Zn alloy was fabricated by mechanical alloying(MA)and hot pressing to serve as biodegradable metal implant.The influence of addition of 1%Si(mass fraction)on the microstructure,mechanical properties and bi...The Mg-6Al-4Zn alloy was fabricated by mechanical alloying(MA)and hot pressing to serve as biodegradable metal implant.The influence of addition of 1%Si(mass fraction)on the microstructure,mechanical properties and bio-corrosion behavior of Mg-6Al-1Zn alloy was studied using X-ray diffractometry,transmission electron microscopy,compression test,as well as immersion,electrochemical test and MTT assay.The results showed that the addition of 1%Si to Mg-6Al-1Zn alloy led to the formation of fine Mg2Si phase with polygonal shape,and increased compressive strength,elongation and improved corrosion resistance.Furthermore,the cell viability of Saos-2 cells has been improved by addition of 1%Si to Mg-6Al-1Zn alloy.According to the results,the magnesium ions released in the methylthiazol tetrazolium(MTT)test have not shown any cell toxicity.All these indicated that the addition of 1%Si improved the properties of Mg-6Al-4Zn alloy for using as a biodegradable implant.展开更多
Major and REE geochemistry and multi-fractal analysis of two types of bauxite(primary bauxite and accumulated bauxite) ores were studied in Pingguo bauxite orefield in western Guangxi,China.The results of geochemical ...Major and REE geochemistry and multi-fractal analysis of two types of bauxite(primary bauxite and accumulated bauxite) ores were studied in Pingguo bauxite orefield in western Guangxi,China.The results of geochemical data show that the accumulated bauxite has a feature of high Al_2O_3 whereas relative low Fe_2O_3 and SiO_2 contents compared to the primary bauxite.The similar chondrite-normalized rare earth element(REE) patterns illustrate that they have a cognate relationship.However,the negative Ce anomalies of primary bauxite and positive Ce anomalies of accumulated bauxite indicate that the ore-forming system changed from reducing environment to oxidation environment.The results of multi-fractal spectrum and parameters of Al_2O_3,Fe_2O_3 and SiO_2 between primary bauxite and accumulated bauxite show that the distinct multi-fractal spectrum parameters reflect the different grade distribution between accumulated and primary bauxite ores.Metallogenic process from primary bauxite to accumulated bauxite is accompanied by the loss of diffluent elements(e.g.,Si and S) and enrichment of stable elements(e.g.,Al and Fe) in the surface environment.Among the rest,the migration mechanism of iron during the evolutionary process from primary ore to accumulated ore can be described as combined leaching and chemical weathering action with participation of sulfur.展开更多
Generation of alum sludge(AS)at drinking water treatment plants represents an environmental liability and adds to the cost of water purification.Consequently,this study explored the feasibility of using low and high c...Generation of alum sludge(AS)at drinking water treatment plants represents an environmental liability and adds to the cost of water purification.Consequently,this study explored the feasibility of using low and high carbon containing alum sludge from two water treatment plants to synthesize zeolite LTA.The hypothesis was that zeolite LTA synthesis was dependant upon alum sludge source and that a range of strategies may be required to optimize zeolite crystallinity.Zeolite characteristics such as morphology,phase composition,crystallinity,and particle size distribution were recorded."One pot"hydrothermal synthesis of precursor gel with molar composition 4.2 Na2O:Al2O3:1.2 SiO_(2):168 H2O at 80℃ for 3 hr resulted in 25 and 46 wt.%zeolite LTA from high and low carbonaceous sludge,respectively.Prior to hydrothermal reaction stage it was discovered that ageing of the gel,addition of zeolite LTA seeds,ultrasonic treatment and calcination all promoted zeolite LTA formation.Calcination of the alum sludge at 700℃ for 2 hr before hydrothermal synthesis resulted in particle size reduction and the highest amount of crystalline zeolite LTA:79 wt.%from low carbon sludge and 65 wt.%from high carbon sludge.Notably,the zeolite crystallinity reported in this study was the higher than previous studies on this topic.The outlined approach may allow value adding of alum waste and produce a commodity which could be used locally by the water treatment plant as a water softener.展开更多
Because the lightness,the gloss and the press-formability of electrogalvanized steel sheets change depending on the morphology of deposited Zn,control of this factor is essential to improving these properties.The effe...Because the lightness,the gloss and the press-formability of electrogalvanized steel sheets change depending on the morphology of deposited Zn,control of this factor is essential to improving these properties.The effects of plating factors on the morphology of deposited Zn were systematically discussed both from the crystallographic viewpoint of epitaxy between Zn and steel and from the electrochemical viewpoint of the overpotential for Zn deposition.Plating factors include crystal orientation of steel substrate,current density,flow rate,temperature,addition of inorganic compounds to the solution and pre-adsorption of organic compounds.These plating factors affect the overpotential for Zn deposition and epitaxy between Zn and steel.The crystal orientation index of the Zn basal plane and the platelet crystal size of Zn are decreased with increasing the overpotential for Zn deposition.They are also decreased with decreasing the epitaxy between Zn and steel,even when the overpotential is kept constant.When the overpotential for Zn deposition is increased,the surface roughness of deposited Zn increases because of an increase in the inclination of the Zn basal plane to the steel substrate.When the epitaxy between Zn and steel is decreased without changing the overpotential,the surface roughness is reduced due to the decrease in platelet crystal size of Zn,although the inclination of the Zn basal plane is somewhat increased.The lightness of deposited Zn is enhanced with decreasing the surface roughness of Zn.展开更多
Impervious surface(IS) is often recognized as the indicator of urban environmental changes. Numerous research efforts have been devoted to studying its spatio-temporal dynamics and ecological effects, especially for t...Impervious surface(IS) is often recognized as the indicator of urban environmental changes. Numerous research efforts have been devoted to studying its spatio-temporal dynamics and ecological effects, especially for the IS in Beijing metropolitan region. However, most previous studies primarily considered the Beijing metropolitan region as a whole without considering the differences and heterogeneity among the function zones. In this study, the subpixel impervious surface results in Beijing within a time series(1991, 2001, 2005, 2011 and 2015) were extracted by means of the classification and regression tree(CART) model combined with change detection models. Then based on the method of standard deviation ellipse, Lorenz curve, contribution index(CI) and landscape metrics, the spatio-temporal dynamics and variations of IS(1991, 2001, 2011 and 2015) in different function zones and districts were analyzed. It is found that the total area of impervious surface in Beijing increased dramatically during the study period, increasing about 144.18%. The deflection angle of major axis of standard deviation ellipse decreased from 47.15° to 38.82°, indicating the major development axis in Beijing gradually moved from northeast-southwest to north-south. Moreover, the heterogeneity of impervious surface’s distribution among 16 districts weakened gradually, but the CI values and landscape metrics in four function zones differed greatly. The urban function extended zone(UFEZ), the main source of the growth of IS in Beijing, had the highest CI values. Its lowest CI value was 1.79 that is still much higher than the highest CI value in other function zones. The core function zone(CFZ), the traditional aggregation zone of impervious surface, had the highest contagion index(CONTAG) values, but it contributed less than UFEZ due to its small area. The CI value of the new urban developed zone(NUDZ) increased rapidly, and it increased from negative to positive and multiplied, becoming animportant contributor to the rise of urban impervious surface. However, the ecological conservation zone(ECZ) had a constant negative contribution all the time, and its CI value decreased gradually. Moreover, the landscape metrics and centroids of impervious surface in different density classes differed greatly. The high-density impervious surface had a more compact configuration and a greater impact on the eco-environment.展开更多
This study compared the microstructure and mechanical characteristics of AA6061-T6 joints produced using friction stir welding(FSW),friction stir vibration welding(FSVW),and tungsten inert gas welding(TIG).FSVW is a m...This study compared the microstructure and mechanical characteristics of AA6061-T6 joints produced using friction stir welding(FSW),friction stir vibration welding(FSVW),and tungsten inert gas welding(TIG).FSVW is a modified version of FSW wherein the joining specimens are vibrated normal to the welding line during FSW.The results indicated that the weld region grains for FSVW and FSW were equiaxed and were smaller than the grains for TIG.In addition,the weld region grains for FSVW were finer compared with those for FSW.Results also showed that the strength,hardness,and toughness values of the joints produced by FSVW were higher than those of the other joints produced by FSW and TIG.The vibration during FSW enhanced dynamic recrystallization,which led to the development of finer grains.The weld efficiency of FSVW was approximately 81%,whereas those of FSW and TIG were approximately 74%and 67%,respectively.展开更多
基金N.B.:IHBI ECR grant,Advance Queensland(AQ)Maternity Fund Award from the Queensland Government(DSITI),Young Researcher Award(2017-YR-RoW-9)from Lush(UK)supporting non-animal testing alternatives,National Health and Medical Research Council(NHMRC)Peter Doherty Early Career Research Fellowship(RF)(APP1091734)+5 种基金John Mills Young Investigator Award(YI0715)from the Prostate Cancer Foundation of Australia(PCFA)P.A.T.:Vice Chancellor’s RF(QUT)and AQ RF(QLD)J.A.C.:NHMRC PRFD.W.H.:Humboldt RF,ARC Industrial Transformation Training Center in Additive Biomanufacturing(IC160100026)NHMRC,World Cancer Foundation,National Breast Cancer Foundation,PCFA.D.W.H.,J.A.C.,C.C.N.:Movember Revolutionary Team Award(from Movember and PCFA).APCRC-Qthe Translational Research Institute are supported by grants from the Australian Government
文摘While stromal interactions are essential in cancer adaptation to hormonal therapies,the effects of bone stroma and androgen deprivation on cancer progression in bone are poorly understood.Here,we tissue-engineered and validated an in vitro microtissue model of osteoblastic bone metastases,and used it to study the effects of androgen deprivation in this microenvironment.The model was established by culturing primary human osteoprogenitor cells on melt electrowritten polymer scaffolds,leading to a mineralized osteoblast-derived microtissue containing,in a 3D setting,viable osteoblastic cells,osteocytic cells,and appropriate expression of osteoblast/osteocyte-derived mRNA and proteins,and mineral content.Direct co-culture of androgen receptordependent/ independent cell lines (LNCaP,C4-2B,and PC3) led cancer cells to display functional and molecular features as observed in vivo.Co-cultured cancer cells showed increased affinity to the microtissues,as a function of their bone metastatic potential.Cocultures led to alkaline phosphatase and collagen-I upregulation and sclerostin downregulation,consistent with the clinical marker profile of osteoblastic bone metastases.LNCaP showed a significant adaptive response under androgen deprivation in the microtissues,with the notable appearance of neuroendocrine transdifferentiation features and increased expression of related markers (dopa decarboxylase,enolase 2).Androgen deprivation affected the biology of the metastatic microenvironment with stronger upregulation of androgen receptor,alkaline phosphatase,and dopa decarboxylase,as seen in the transition towards resistance.The unique microtissues engineered here represent a substantial asset to determine the involvement of the human bone microenvironment in prostate cancer progression and response to a therapeutic context in this microenvironment.
基金supported by the Science and Technology Development Fund(FDCT),Macao SAR(No.0149/2022/A),and(No.0046/2024/AFJ)Guangdong Science and Technology Department(No.2023QN10C305)。
文摘A high humidity-resistant,dual mechanical responsive,and reversible mechanochromic wrinkling system based on a VHB 4910-polydimethylsiloxane(PDMS)substrate with a thin film consisting of 90 wt%poly(vinyl butyral)(PVB)and 10 wt%hydroxypropyl cellulose(HPC)has been reported.The wrinkling system exhibited significant optical tuning from transparent to opaque states with 50%changes in transmittance,which was achieved through the dual mechanical modes of pre-stretching and releasing processes or bending.Upon exposure to ethanol vapor or a re-flattening process,wrinkles can be erased,yielding a transparent state.Consequently,the wrinkling system could be reversibly switched between transparency and opacity for 1000 cycles with marginal changes in the optical performance.Owing to the insolubility of PVB in water,the wrinkling patterns exhibited excellent durability in high-humidity environments(relative humidity(RH)=99%).Furthermore,the smart encryption device is also demonstrated via mechano-controlled surface topography by patterning the wrinkling system,suggesting potential applications of the designed structure in smart windows,anti-counterfeiting,dynamic display,optical information encryption,and rewritable surfaces.
文摘Accurate estimation of evapotranspiration(ET)is crucial for efficient water resource management,particularly in the face of climate change and increasing water scarcity.This study performs a bibliometric analysis of 352 articles and a systematic review of 35 peer-reviewed papers,selected according to PRISMA guidelines,to evaluate the performance of Hybrid Artificial Neural Networks(HANNs)in ET estimation.The findings demonstrate that HANNs,particularly those combining Multilayer Perceptrons(MLPs),Recurrent Neural Networks(RNNs),and Convolutional Neural Networks(CNNs),are highly effective in capturing the complex nonlinear relationships and tem-poral dependencies characteristic of hydrological processes.These hybrid models,often integrated with optimization algorithms and fuzzy logic frameworks,significantly improve the predictive accuracy and generalization capabilities of ET estimation.The growing adoption of advanced evaluation metrics,such as Kling-Gupta Efficiency(KGE)and Taylor Diagrams,highlights the increasing demand for more robust performance assessments beyond traditional methods.Despite the promising results,challenges remain,particularly regarding model interpretability,computational efficiency,and data scarcity.Future research should prioritize the integration of interpretability techniques,such as attention mechanisms,Local Interpretable Model-Agnostic Explanations(LIME),and feature importance analysis,to enhance model transparency and foster stakeholder trust.Additionally,improving HANN models’scalability and computational efficiency is crucial,especially for large-scale,real-world applications.Approaches such as transfer learning,parallel processing,and hyperparameter optimization will be essential in overcoming these challenges.This study underscores the transformative potential of HANN models for precise ET estimation,particularly in water-scarce and climate-vulnerable regions.By integrating CNNs for automatic feature extraction and leveraging hybrid architectures,HANNs offer considerable advantages for optimizing water management,particularly agriculture.Addressing challenges related to interpretability and scalability will be vital to ensuring the widespread deployment and operational success of HANNs in global water resource management.
基金the financial support under the Project PID2021-126166OB-I00 funded by MCIN/AEI/10.13039/501100011033 and by“ERDF A way of making Europe”(European Union)the Grant CNS2023-144665 funded by MCIN/AEI/10.13039/501100011033+1 种基金by the“European Union NextGenerationEU/PRTR.”the CSIC for the financial support under the project PIE-20216AT012.
文摘The corrosion behavior of the laser powder bed fusion(LPBF)AZ91 magnesium alloy was investigated by comparing its longitudinal and transverse sections with the cast AZ91 alloy.Microstructural analysis revealed a fine,homogeneous Mg_(17)Al_(12) distribution in LPBF samples,contrasting with the network-like structure in the cast alloy.Electrochemical and hydrogen evolution tests demonstrated no significant anisotropy in LPBF sections,but they exhibited higher corrosion rates than the cast alloy.Potentiodynamic polarization and electrochemical impedance spectroscopy confirmed that the corrosion process was cathodically controlled by the Mg_(17)Al_(12) phase fraction.Scanning vibrating electrode technique further validated these findings,highlighting lower electrochemical activity in cast AZ91 alloy.
基金finically supported by the National Natural Science Foundation of China(Nos.52261135548,52302153,and 52402155)the China Postdoctoral Science Foundation(Nos.GZC20232075 and 2023M742767)+2 种基金The research was made possible by Russian Science Foundation(Project No 23-42-00116)The equipment of the Ural Center for Shared Use“Modern nanotech-nology”Ural Federal University(Reg.No2968)whichis supported by the Ministry of Science and Higher Education RF(Project No 075-15-2021-677)was usedThe SEM work was done at International Center for Dielectric Research(ICDR),Xi’an Jiaotong University,Xi’an,China.
文摘The structural phase transitions and ferroelectric dynamics of lead-free AgNbO_(3)have attracted consid-erable attention owing to their potential in energy-storage device applications.Here,we examine the impact of Li+doping on the phase transitions and polarization behavior of(Ag_(1-x)Li_(x))NbO_(3)(x=0-7%)ceramics through comprehensive dielectric and ferroelectric analyses.Rietveld refinement reveals a Li+-induced phase transition from Pbcm to R3c,with x=5%and x=6%compositions near the morphotropic phase boundary(MPB).Dielectric anomalies identify key characteristic temperatures,supporting the con-struction of a low-field phase diagram.High-field studies uncover a direct relationship between phase structure and polarization behavior,culminating in a high-field phase diagram.Near-MPB compositions exhibit distinct structural states,elucidating the mechanisms of reversible and irreversible phase transi-tions.This work provides a comprehensive explanation of the evolution of hysteresis loop profiles,capturing their progression from double hysteresis loops to square loops and their subsequent reversion to double loops under varying electric field and temperature conditions.These temperature-composition(T-x)and temperature-electric field(T-E)phase diagrams provide a robust framework for understanding phase evolution,offering critical insights into optimizing AgNbO_(3)-based ceramics for advanced functional applications.
文摘Accurate capacity and State of Charge(SOC)estimation are crucial for ensuring the safety and longevity of lithium-ion batteries in electric vehicles.This study examines ten machine learning architectures,Including Deep Belief Network(DBN),Bidirectional Recurrent Neural Network(BiDirRNN),Gated Recurrent Unit(GRU),and others using the NASA B0005 dataset of 591,458 instances.Results indicate that DBN excels in capacity estimation,achieving orders-of-magnitude lower error values and explaining over 99.97%of the predicted variable’s variance.When computational efficiency is paramount,the Deep Neural Network(DNN)offers a strong alternative,delivering near-competitive accuracy with significantly reduced prediction times.The GRU achieves the best overall performance for SOC estimation,attaining an R^(2) of 0.9999,while the BiDirRNN provides a marginally lower error at a slightly higher computational speed.In contrast,Convolutional Neural Networks(CNN)and Radial Basis Function Networks(RBFN)exhibit relatively high error rates,making them less viable for real-world battery management.Analyses of error distributions reveal that the top-performing models cluster most predictions within tight bounds,limiting the risk of overcharging or deep discharging.These findings highlight the trade-off between accuracy and computational overhead,offering valuable guidance for battery management system(BMS)designers seeking optimal performance under constrained resources.Future work may further explore advanced data augmentation and domain adaptation techniques to enhance these models’robustness in diverse operating conditions.
基金supported by the Natural Science Foundation of Hebei Province of China(E2022203109)the National Natural Sci-ence Foundation of China(Grant No.52202049,52103322)+5 种基金the Natural Science Foundation of Jiangxi Province of China(Grant No.20202BAB214010)the Open Funds of the State Key Laboratory of Metastable Materials Science and Technology(Grant No.201906)Ganzhou Science and Technology Project(Grant No.202060)the Program of Qingjiang Excellent Young Talents,Jiangxi Univer-sity of Science and Technology(JXUSTQJYX2020002)China Post-doctoral Science Foundation(2023M731866)the Macao Young Scholars Program(AM2021015).
文摘Boron suboxide(B_(6)O)is recognized as a superhard material with a low mass density,high resistance to chemical wear,and excellent wear resistance.Despite its desirable properties,the limited fracture tough-ness of B_(6)O restricts its application in industrial contexts.This study presents the structural and me-chanical characterization of B_(6)O-SiC nanocomposites,which were synthesized via a high-pressure high-temperature sintering process of B_(6)O powders and SiC whiskers.The sintering process induced fragmen-tation of SiC whiskers,resulting in the homogenous distribution of SiC fragments within the B_(6)O matrix.An increase in SiC content was observed to decrease the composite’s hardness,while initially reducing then enhancing its toughness.The nanocomposites containing 20 wt%and 30 wt%SiC whiskers exhibited significant improvements in fracture toughness,averaging 6.5 MPa m^(1/2)and 7.0 MPa m^(1/2),respectively-approximately threefold the toughness of polycrystalline B_(6)O-while sustaining high hardness values of 36.3 GPa and 35.6 GPa on average.Microstructural analyses revealed that the composites’superior me-chanical performance is due to the presence of strong grain boundaries,as well as a high density of nan-otwins and stacking faults.The findings demonstrate a viable method for producing B_(6)O-based nanocom-posites with enhanced hardness and toughness,potentially expanding their industrial applicability.
基金financially supported by the Ongoing Research Funding Program(ORF-2025-846),King Saud University,Riyadh,Saudi Arabia.
文摘Protecting Supervisory Control and Data Acquisition-Industrial Internet of Things(SCADA-IIoT)systems against intruders has become essential since industrial control systems now oversee critical infrastructure,and cyber attackers more frequently target these systems.Due to their connection of physical assets with digital networks,SCADA-IIoT systems face substantial risks from multiple attack types,including Distributed Denial of Service(DDoS),spoofing,and more advanced intrusion methods.Previous research in this field faces challenges due to insufficient solutions,as current intrusion detection systems lack the necessary accuracy,scalability,and adaptability needed for IIoT environments.This paper introduces CyberFortis,a novel cybersecurity framework aimed at detecting and preventing cyber threats in SCADA-IIoT systems.CyberFortis presents two key innovations:Firstly,Siamese Double Deep Q-Network with Autoencoders(Siamdqn-AE)FusionNet,which enhances intrusion detection by combining deep Q-Networks with autoencoders for improved attack detection and feature extraction;and secondly,the PopHydra Optimiser,an innovative solution to compute reinforcement learning discount factors for better model performance and convergence.This method combines Siamese deep Q-Networks with autoencoders to create a system that can detect different types of attacks more effectively and adapt to new challenges.CyberFortis is better than current top attack detection systems,showing higher scores in important areas like accuracy,precision,recall,and F1-score,based on data from CICIoT 2023,UNSW-NB 15,and WUSTL-IIoT datasets.Results from the proposed framework show a 97.5%accuracy rate,indicating its potential as an effective solution for SCADA-IIoT cybersecurity against emerging threats.The research confirms that the proposed security and resilience methods are successful in protecting vital industrial control systems within their operational environments.
基金Projects(41877511,41842020)supported by the National Natural Science Foundation of ChinaProject(201509048)supported by the Environmental Protection’s Special Scientific Research for Chinese Public Welfare Industry
文摘This study focused on leaching behavior of alkaline anion and sodium in bauxite residue through ammonium chloride treatment.The results showed that the pH of bauxite residue decreased from 10.49 to 8.93,total alkaline anion(HCO3^-,CO3^2-,OH^-,AlO2^-)concentration reduced from 38.89 to 25.50 mmol/L,leaching rate of soluble sodium was 80.86%with ammonium chloride addition of 0.75%,liquid/solid(L/S)ratio of 3(mL/g),temperature of 30°C and reaction time of 18 h;L/S ratio was the main factor affecting the removal of alkaline anion and the leaching of sodium.Furthermore,ammonium chloride promoted the dissolution of diaspore and changed the micro/morphological characteristics with the increase of massive structure.The findings of this work will contribute to achieve soil-formation of bauxite residue.
基金Shahid Chamran University of Ahvaz for supporting this research
文摘This study has evaluated the effect of different levels of cold rolling（from 0 to 50%）on the microstructural,magnetic,and mechanical properties and the corrosion behavior of 316L austenitic stainless steel in Na Cl（1 mol/L）＋H_2SO_4（0.5 mol/L）solution.Microstructural examinations using optical microscopy revealed the development of a morphological texture from coaxial to elongated grains during the cold-rolling process.Phase analysis carried out on the basis of X-ray diffraction confirmed the formation of the ferromagneticα′-martensite phase under the stresses applied during cold rolling.This finding is in agreement with magnetic measurements using a vibrating sample magnetometer.Mechanical properties determined by tensile and Vickers microhardness tests demonstrated an upward trend in the hardness-to-yield strength ratio with increasing cold-rolling percentage,representing a reduction in the material’s work-hardening ability.Uniform and localized corrosion parameters were estimated via potentiodynamic polarization corrosion tests and electrochemical impedance spectroscopy.In contrast to the uniform corrosion,wherein the corrosion current density increased with increasing cold-working degree because of the high density of microstructural defects,the passive potential range and breakdown potential increased by cold working,showing greater resistance to pit nucleation.Although pits were formed,the cold-rolled material repassivation tendency decreased because of the broader hysteresis anodic loop,as confirmed experimentally by observation of the microscopic features after electrochemical cyclic polarization evaluations.
基金funded through the financial support of “Australian Government Research Training Program (RTP) Stipend”supported by generous funding from the Science and Engineering Faculty (SEF-QUT)
文摘This study revealed the relationship between the presence of calcium impurities and ammoniacal nitrogen concentration upon crystallization of struvite.The research hypothesis was that the presence of both calcium and high concentrations of ammoniacal nitrogen(328–1000 mg/L)in waste activated sludge may influence the struvite quality and acid stability.Hence,we studied the impact of Ca:Mg ratio upon morphology,particle size,purity and dissolution of struvite,in the presence of varying levels of excess ammoniacal nitrogen.X-ray diffraction revealed that up to 31.4%amorphous material was made which was assigned to hydroxyapatite.Increasing the ammoniacal nitrogen concentration and elevation of the Mg:Ca ratio maximized the presence of struvite.Struvite particle size was also increased by ammoniacal nitrogen as was twinning of the crystals.Tests with dilute solutions of organic acid revealed the sensitivity of struvite dissolution to the physical characteristics of the struvite.Smaller particles(21.2μm)dissolved at higher rates than larger particles(35.86μm).However,struvite dissolved rapidly as the p H was further reduced irrespective of the physical characteristics.Therefore,addition of struvite to low p H soils was not viewed as beneficial in terms of controlled nutrient release.Overall,this study revealed that waste activated sludge effluent with high ammoniacal nitrogen was prospective for synthesis of high quality struvite material.
文摘A low-alloy gray cast iron containing hard carbide-forming elements, such as vanadium and chromium, was cast by sand mould casting. Its wear resistance was compared with that of an untreated gray cast iron. Three different loading conditions were tested under a con- stant speed. It was observed that this alloy could reduce the wear loss of standard gray cast iron by up to 89%, which was much greater than what was achieved in previous reports. Scanning electron microscopy （SEM） was used to determine the predominant wear mechanism of both the alloys. In a mild wear regime, the oxidative mechanism was predominant; however, in a severe wear regime, this mechanism was not predominant and the adhesive mechanism was involved. EDX analysis was conducted to evaluate the quantitative amounts of elements in the tribochemical films formed on the wear tracks.
基金financial support of Islamic Azad University, Dezful Branch for the project No. 6230
文摘The influence of combination of different designated precipitation hardening and cold working on the tensile properties of 6061 aluminum alloy was investigated. The results indicate that applying single aging at 180 ℃ for 4 h in different thermal-mechanical treatments improves both the strength and elongation. However, double aging does not improve the mechanical properties. In addition, pre-aging shows a negative effect on the subsequent precipitation hardening of material. The changes in mechanical properties were discussed by explanation of microstructural evolution due to the competition of precipitation hardening, strain hardening and work softening processes.
基金financial support provided by the RIF project(Grant No.PolyU R5037-18F)from the Research Grants Council(RGC)of Hong Kong is gratefully acknowledged。
文摘Compression index Ccis an essential parameter in geotechnical design for which the effectiveness of correlation is still a challenge.This paper suggests a novel modelling approach using machine learning(ML)technique.The performance of five commonly used machine learning(ML)algorithms,i.e.back-propagation neural network(BPNN),extreme learning machine(ELM),support vector machine(SVM),random forest(RF)and evolutionary polynomial regression(EPR)in predicting Cc is comprehensively investigated.A database with a total number of 311 datasets including three input variables,i.e.initial void ratio e0,liquid limit water content wL,plasticity index Ip,and one output variable Cc is first established.Genetic algorithm(GA)is used to optimize the hyper-parameters in five ML algorithms,and the average prediction error for the 10-fold cross-validation(CV)sets is set as thefitness function in the GA for enhancing the robustness of ML models.The results indicate that ML models outperform empirical prediction formulations with lower prediction error.RF yields the lowest error followed by BPNN,ELM,EPR and SVM.If the ranges of input variables in the database are large enough,BPNN and RF models are recommended to predict Cc.Furthermore,if the distribution of input variables is continuous,RF model is the best one.Otherwise,EPR model is recommended if the ranges of input variables are small.The predicted correlations between input and output variables using five ML models show great agreement with the physical explanation.
文摘The Mg-6Al-4Zn alloy was fabricated by mechanical alloying(MA)and hot pressing to serve as biodegradable metal implant.The influence of addition of 1%Si(mass fraction)on the microstructure,mechanical properties and bio-corrosion behavior of Mg-6Al-1Zn alloy was studied using X-ray diffractometry,transmission electron microscopy,compression test,as well as immersion,electrochemical test and MTT assay.The results showed that the addition of 1%Si to Mg-6Al-1Zn alloy led to the formation of fine Mg2Si phase with polygonal shape,and increased compressive strength,elongation and improved corrosion resistance.Furthermore,the cell viability of Saos-2 cells has been improved by addition of 1%Si to Mg-6Al-1Zn alloy.According to the results,the magnesium ions released in the methylthiazol tetrazolium(MTT)test have not shown any cell toxicity.All these indicated that the addition of 1%Si improved the properties of Mg-6Al-4Zn alloy for using as a biodegradable implant.
基金Project(GX2007CAQB01)supported by the Key Research Project of Aluminum Corporation of China LimitedProject(41502067)supported by the National Natural Science Foundation of China
文摘Major and REE geochemistry and multi-fractal analysis of two types of bauxite(primary bauxite and accumulated bauxite) ores were studied in Pingguo bauxite orefield in western Guangxi,China.The results of geochemical data show that the accumulated bauxite has a feature of high Al_2O_3 whereas relative low Fe_2O_3 and SiO_2 contents compared to the primary bauxite.The similar chondrite-normalized rare earth element(REE) patterns illustrate that they have a cognate relationship.However,the negative Ce anomalies of primary bauxite and positive Ce anomalies of accumulated bauxite indicate that the ore-forming system changed from reducing environment to oxidation environment.The results of multi-fractal spectrum and parameters of Al_2O_3,Fe_2O_3 and SiO_2 between primary bauxite and accumulated bauxite show that the distinct multi-fractal spectrum parameters reflect the different grade distribution between accumulated and primary bauxite ores.Metallogenic process from primary bauxite to accumulated bauxite is accompanied by the loss of diffluent elements(e.g.,Si and S) and enrichment of stable elements(e.g.,Al and Fe) in the surface environment.Among the rest,the migration mechanism of iron during the evolutionary process from primary ore to accumulated ore can be described as combined leaching and chemical weathering action with participation of sulfur.
文摘Generation of alum sludge(AS)at drinking water treatment plants represents an environmental liability and adds to the cost of water purification.Consequently,this study explored the feasibility of using low and high carbon containing alum sludge from two water treatment plants to synthesize zeolite LTA.The hypothesis was that zeolite LTA synthesis was dependant upon alum sludge source and that a range of strategies may be required to optimize zeolite crystallinity.Zeolite characteristics such as morphology,phase composition,crystallinity,and particle size distribution were recorded."One pot"hydrothermal synthesis of precursor gel with molar composition 4.2 Na2O:Al2O3:1.2 SiO_(2):168 H2O at 80℃ for 3 hr resulted in 25 and 46 wt.%zeolite LTA from high and low carbonaceous sludge,respectively.Prior to hydrothermal reaction stage it was discovered that ageing of the gel,addition of zeolite LTA seeds,ultrasonic treatment and calcination all promoted zeolite LTA formation.Calcination of the alum sludge at 700℃ for 2 hr before hydrothermal synthesis resulted in particle size reduction and the highest amount of crystalline zeolite LTA:79 wt.%from low carbon sludge and 65 wt.%from high carbon sludge.Notably,the zeolite crystallinity reported in this study was the higher than previous studies on this topic.The outlined approach may allow value adding of alum waste and produce a commodity which could be used locally by the water treatment plant as a water softener.
文摘Because the lightness,the gloss and the press-formability of electrogalvanized steel sheets change depending on the morphology of deposited Zn,control of this factor is essential to improving these properties.The effects of plating factors on the morphology of deposited Zn were systematically discussed both from the crystallographic viewpoint of epitaxy between Zn and steel and from the electrochemical viewpoint of the overpotential for Zn deposition.Plating factors include crystal orientation of steel substrate,current density,flow rate,temperature,addition of inorganic compounds to the solution and pre-adsorption of organic compounds.These plating factors affect the overpotential for Zn deposition and epitaxy between Zn and steel.The crystal orientation index of the Zn basal plane and the platelet crystal size of Zn are decreased with increasing the overpotential for Zn deposition.They are also decreased with decreasing the epitaxy between Zn and steel,even when the overpotential is kept constant.When the overpotential for Zn deposition is increased,the surface roughness of deposited Zn increases because of an increase in the inclination of the Zn basal plane to the steel substrate.When the epitaxy between Zn and steel is decreased without changing the overpotential,the surface roughness is reduced due to the decrease in platelet crystal size of Zn,although the inclination of the Zn basal plane is somewhat increased.The lightness of deposited Zn is enhanced with decreasing the surface roughness of Zn.
基金National Basic Research Program of China,No.2015CB953603National Natural Science Foundation of China,No.41671339State Key Laboratory of Earth Surface Processes and Resource Ecology,No.2017-FX-01(1)
文摘Impervious surface(IS) is often recognized as the indicator of urban environmental changes. Numerous research efforts have been devoted to studying its spatio-temporal dynamics and ecological effects, especially for the IS in Beijing metropolitan region. However, most previous studies primarily considered the Beijing metropolitan region as a whole without considering the differences and heterogeneity among the function zones. In this study, the subpixel impervious surface results in Beijing within a time series(1991, 2001, 2005, 2011 and 2015) were extracted by means of the classification and regression tree(CART) model combined with change detection models. Then based on the method of standard deviation ellipse, Lorenz curve, contribution index(CI) and landscape metrics, the spatio-temporal dynamics and variations of IS(1991, 2001, 2011 and 2015) in different function zones and districts were analyzed. It is found that the total area of impervious surface in Beijing increased dramatically during the study period, increasing about 144.18%. The deflection angle of major axis of standard deviation ellipse decreased from 47.15° to 38.82°, indicating the major development axis in Beijing gradually moved from northeast-southwest to north-south. Moreover, the heterogeneity of impervious surface’s distribution among 16 districts weakened gradually, but the CI values and landscape metrics in four function zones differed greatly. The urban function extended zone(UFEZ), the main source of the growth of IS in Beijing, had the highest CI values. Its lowest CI value was 1.79 that is still much higher than the highest CI value in other function zones. The core function zone(CFZ), the traditional aggregation zone of impervious surface, had the highest contagion index(CONTAG) values, but it contributed less than UFEZ due to its small area. The CI value of the new urban developed zone(NUDZ) increased rapidly, and it increased from negative to positive and multiplied, becoming animportant contributor to the rise of urban impervious surface. However, the ecological conservation zone(ECZ) had a constant negative contribution all the time, and its CI value decreased gradually. Moreover, the landscape metrics and centroids of impervious surface in different density classes differed greatly. The high-density impervious surface had a more compact configuration and a greater impact on the eco-environment.
文摘This study compared the microstructure and mechanical characteristics of AA6061-T6 joints produced using friction stir welding(FSW),friction stir vibration welding(FSVW),and tungsten inert gas welding(TIG).FSVW is a modified version of FSW wherein the joining specimens are vibrated normal to the welding line during FSW.The results indicated that the weld region grains for FSVW and FSW were equiaxed and were smaller than the grains for TIG.In addition,the weld region grains for FSVW were finer compared with those for FSW.Results also showed that the strength,hardness,and toughness values of the joints produced by FSVW were higher than those of the other joints produced by FSW and TIG.The vibration during FSW enhanced dynamic recrystallization,which led to the development of finer grains.The weld efficiency of FSVW was approximately 81%,whereas those of FSW and TIG were approximately 74%and 67%,respectively.
