Chemically precipitated β type nickel hydroxide powder was surface modified by electroless deposition of Co Zn coatings,and physical properties of both the modified and unmodified nickel hydroxide were characterized ...Chemically precipitated β type nickel hydroxide powder was surface modified by electroless deposition of Co Zn coatings,and physical properties of both the modified and unmodified nickel hydroxide were characterized by scanning electron microscopy (SEM), specific surface area (BET), X ray diffraction (XRD) and X ray photoelectron spectroscopy (XPS). It has been found that Co and Zn components of the surface electroless coatings exist in the oxidized state. Electrochemical performances of pasted nickel electrodes using the modified nickel hydroxide as an active material were investigated, and compared with those of the electrodes prepared with the unmodified nickel hydroxide. Charge/discharge tests show that the modified nickel hydroxide electrodes exhibit better performances in the charge efficiency, specific discharge capacity and active material utilization. Their resistance to swelling with cycling is also superior to that of the unmodified nickel hydroxide electrodes. Cyclic voltammetric (CV) studies indicate that the modified electrodes have a higher electrochemical activity, and the porous pasted nickel electrodes have some distinguished CV characteristics in comparison with those of the thin film nickel electrodes.展开更多
Three types of activators such as sodium hydroxide,calcium oxide and triethanolamine(TEA)are used to establish different activation environments to address the problems associated with the process of activating fly as...Three types of activators such as sodium hydroxide,calcium oxide and triethanolamine(TEA)are used to establish different activation environments to address the problems associated with the process of activating fly ash paste.We conducted mechanical tests and numerical simulations to understand the evolution of microstructure,and used environmental scanning electron microscopy(ESEM)and energy dispersive spectroscopy(EDS)techniques to analyze the microenvironments of the samples.The mechanical properties of fly ash paste under different activation conditions and the changes in the microstructure and composition were investigated.The results revealed that under conditions of low NaOH content(1%-3%),the strength of the sample increased significantly.When the content exceeded 4%,the rate of increase in strength decreased.Based on the results,the optimal NaOH content was identified,which was about 4%.A good activation effect,especially for short-term activation(3-7 d),was achieved using TEA under high doping conditions.The activation effect was poor for long-term strength after 28 days.The CaO content did not significantly affect the degree of activation achieved.The maximum effect was exerted when the content of CaO was 2%.The virtual cement and concrete testing laboratory(VCCTL)was used to simulate the hydration process,and the results revealed that the use of the three types of activators accelerated the formation of Ca(OH)_(2) in the system.The activators also corroded the surface of the fly ash particles,resulting in a pozzolanic reaction.The active substances in fly ash were released efficiently,and hydration was realized.The pores were filled with hydration products,and the microstructure changed to form a new frame of paste filling that helped improve the strength of fly ash paste.展开更多
Introduction The widespread use of cement in concrete leads to increased carbon emissions,so the demand for supplementary cementitious materials increases significantly.Limestone powder and steel slag powder are widel...Introduction The widespread use of cement in concrete leads to increased carbon emissions,so the demand for supplementary cementitious materials increases significantly.Limestone powder and steel slag powder are widely used as supplementary cementitious materials in modern concrete.However,for UHPC and self-compacting concrete,an extremely low water/binder(W/B)ratio is on one hand a key factor in achieving ultra-high strength and ultra-low porosity of the materials,on the other hand,also leads to the deterioration of the rheological properties of the fresh paste.Meanwhile,the existing researches focus on the influence of single limestone powder or steel slag powder on the mechanical properties or microstructure of cement-based materials.Little work on the influence of steel slag powder or limestone powder on the rheological properties of composite paste at an extremely low water/binder ratio has been investigated quantitatively.The mechanism of the effect of steel slag powder or limestone powder on the rheological properties of composite paste at extremely low water/binder ratios is still unclear.In this work,the effects of steel slag powder and limestone powder on the rheological properties of composite paste at different low water/binder ratios were analyzed via determining the flow diameter,setting time,marsh cone flow time,rheological parameters,and total organic carbon content.Methods A composite paste was prepared with P.I 42.5 ordinary Portland cement,steel slag powder,limestone powder,blast furnace slag and silica fume as raw materials in a certain proportion.To achieve the preparation of composite paste with extremely low water/binder ratios,a polycarboxylate superplasticizer with a water/reducing rate of 40%(Jiangsu Subot New Materials Co.,Ltd.,China)was used.The dosage of polycarboxylate superplasticizer for the composite paste with different water/binder ratios of 0.16 and 0.21 was 2%and 0.8%,respectively.Composite pastes with different proportions of steel slag powder or limestone powder at water/binder ratios of 0.16 and 0.21 were prepared.The flow diameter(i.e.,the larger the flow diameter,the better the fluidity),setting time(i.e.,the time when the fluidity is lost)and marsh cone flow time(i.e.,the shorter the flow time,the better the fluidity)were determined to analyze the fluidity of the composite pastes.the rheological properties of composite paste at a water/binder ratio of 0.16 for rheological properties tests were determined,and the rheological parameters were obtained by the H-B model.The adsorption performance of the polycarboxylate superplasticizer was analyzed by testing the TOC content.Results and discussion When the ratio of water/binder is 0.16,both limestone powder and steel slag powder initially increase the flow diameter of the composite paste.However,the fluidity of the composite paste decreases over time,and the reduction is more pronounced with steel slag powder.This is because the nucleation and hydration promotion effect of limestone powder can reduce the loss rate of flow diameter,while the rough particles of steel slag powder increase the internal friction force,resulting in a decrease in the flow diameter of composite paste.Adding limestone powder and steel slag powder both shortens the setting time and marsh cone flow time of the composite paste.However,the steel slag powder addition of 30%delays the final setting time due to its delaying effect.Also,limestone powder can enhance the thixotropy and reduce the yield stress and plastic viscosity,thereby improving the rheological properties.In contrast,steel slag powder can increase the yield stress and plastic viscosity,thereby weakening the rheological properties and thixotropy.Steel slag powder and limestone powder both can enhance the adsorption effect of polycarboxylate superplasticizer.Steel slag powder has a stronger adsorption effect.The composite paste containing limestone powder has a higher free water content.This is because the rough and porous surface of steel slag itself and the uneven particle shape lead to the physical adsorption of polycarboxylate superplasticizer molecules on the surface of steel slag particles,thereby reducing the effective content of the water reducer dispersion.Increasing the water/binder ratio to 0.21 results in a decrease in the flow diameter of the composite paste.Furthermore,the setting time and marsh cone flow time can prolong due to the reduction in the dosage of polycarboxylate superplasticizer.Conclusions The results showed that the fluidity loss rate of composite paste with limestone powder could be lower than that of composite paste with steel slag powder.Compared to steel slag powder,the addition of limestone powder reduced the setting time and marsh cone flow time of the composite paste.The addition of limestone powder could shorten the yield stress and plastic viscosity of the composite paste.Therefore,the composite paste with limestone powder had better rheological properties and stronger thixotropy rather than that with steel slag powder.The addition of limestone powder could improve the rheological properties of the composite paste.Compared to composite paste with limestone powder,a better adsorption effect of polycarboxylate superplasticizer on the surface of the composite binder with steel slag powder could be obtained.The free water content of the composite paste with limestone powder was still higher than that of the composite paste with steel slag powder.The fluidity and rheological properties of the composite paste with limestone powder could be better.The comprehensive analysis indicated that a positive effect of limestone powder on rheological properties of composite paste at an extremely low water/binder ratio could be more dominant than that of steel slag powder.展开更多
Pear paste is a traditional preparation with both medicinal and nutritional functions.The“pear”,as its core ingredient,plays a crucial role in the efficacy of the preparation.This paper,through the interdisciplinary...Pear paste is a traditional preparation with both medicinal and nutritional functions.The“pear”,as its core ingredient,plays a crucial role in the efficacy of the preparation.This paper,through the interdisciplinary integration of evidence from traditional Chinese medicine,food chemistry,molecular biology,and clinical medicine,constructs a complete“raw material-component transformation-biological regulation”model for the first time.It is found that in pear paste,pears not only serve as a functional matrix.The polysaccharide-polyphenol-triterpene complex system forms a multi-target cough-relieving and anti-inflammatory network through dual regulation of TRPV1/TRPA1 ion channels,inhibition of the NLRP3 inflammasome,and metabolites of gut microbiota such as SCFAs.The research results provide a theoretical breakthrough for the modern development of pear paste and a scientific basis for the modernization of traditional preparations.展开更多
Aceh in Indonesia is rich inmarine resources and abundant fishery products such as oyster.Traditionally,fishermen only harvest oysters and discard the shells,which can cause pollution and environmental contamination.W...Aceh in Indonesia is rich inmarine resources and abundant fishery products such as oyster.Traditionally,fishermen only harvest oysters and discard the shells,which can cause pollution and environmental contamination.Waste Oyster Shells(WOS)contain a high percentage of calcium carbonate(CaCO_(3))that experiences thermal decomposition at high temperature,following the reaction CaCO_(3)→CaO+CO_(2)(ΔT=825℃).At temperature>900℃,dead-burned lime is formed,which severely influences CaO reactivity.However,the optimum temperature for producing high CaO content is still uncertain.Therefore,this study aimed to determine the optimum calcination temperature to produce high CaO content,assess initial setting time of WOS paste,and identify the best compressive strength of paste.For the experiment,WOS was used as a partial cement replacement(with a size of 0.075 mm)in paste at a proportion of 5%and calcined at temperature of 700℃,800℃,900℃,and 1000℃.The specimens used were an ebonite ring(dimensions:70 mm bottom diameter,60 mm top diameter,and 40 mm height)and a cube(dimensions:5 cm×5 cm×5 cm).The experiment was conducted following the ASTM(American Society for Testing andMaterials)standards and optimumcompressive strength values were analyzed using ANOVA(Analysis of Variance)and Response Surface Methodology(RSM)through the Design Expert software.The results showed that WOS calcined at 1000℃ increased CaO content by approximately 57.40%.Furthermore,the initial setting time test of 5%WOS paste at 1000℃ showed a more uniform binding performance compared to conventional cement paste,with an initial setting time of 75 min and a penetration depth of 15 mm.In line with the analysis,optimum compressive strength of 71.028 MPa with a desirability value of 0.986 was achieved at 5%cement replacement and calcination temperature of 786.44℃.展开更多
With the growing demand for sustainable development in the mining industry,cemented paste backfill(CPB)materials,primarily composed of tailings,play a crucial role in mine backfilling and underground support systems.T...With the growing demand for sustainable development in the mining industry,cemented paste backfill(CPB)materials,primarily composed of tailings,play a crucial role in mine backfilling and underground support systems.To enhance the mechanical properties of CPB materials,fiber reinforcement technology has gradually gained attention,though challenges remain in predicting its performance.This study develops a hybrid model based on the adaptive equilibrium optimizer(adap-EO)-enhanced XGBoost method for accurately predicting the uniaxial compressive strength of fiber-reinforced CPB.Through systematic comparison with various other machine learning methods,results demonstrate that the proposed hybridmodel exhibits excellent predictive performance on the test set,achieving a coefficient of determination(R^(2))of 0.9675,root mean square error(RMSE)of 0.6084,and mean absolute error(MAE)of 0.4620.Input importance analysis reveals that cement-tailings ratio,curing time,and concentration are the three most critical factors affectingmaterial strength,with cement-tailings ratio showing a positive correlation with strength,concentrations above 70% significantly improvingmaterial strength,and curing periods beyond 28 days being essential for strength development.Fiber parameters contribute secondarily but notably to material strength,with fiber length exhibiting an optimal range of approximately 12 mm.This study not only provides a high-precision strength prediction model but also reveals the inherent correlations between various parameters and material performance,offering scientific basis for mixture optimization and engineering applications of fiber-reinforced CPB materials.展开更多
The multi-objective optimization of backfill effect based on response surface methodology and desirability function(RSM-DF)was conducted.Firstly,the test results show that the uniaxial compressive strength(UCS)increas...The multi-objective optimization of backfill effect based on response surface methodology and desirability function(RSM-DF)was conducted.Firstly,the test results show that the uniaxial compressive strength(UCS)increases with cement sand ratio(CSR),slurry concentration(SC),and curing age(CA),while flow resistance(FR)increases with SC and backfill flow rate(BFR),and decreases with CSR.Then the regression models of UCS and FR as response values were established through RSM.Multi-factor interaction found that CSR-CA impacted UCS most,while SC-BFR impacted FR most.By introducing the desirability function,the optimal backfill parameters were obtained based on RSM-DF(CSR is 1:6.25,SC is 69%,CA is 11.5 d,and BFR is 90 m^(3)/h),showing close results of Design Expert and high reliability for optimization.For a copper mine in China,RSM-DF optimization will reduce cement consumption by 4758 t per year,increase tailings consumption by about 6700 t,and reduce CO_(2)emission by about 4758 t.Thus,RSM-DF provides a new approach for backfill parameters optimization,which has important theoretical and practical values.展开更多
Adjustment of the sowing date is a widely used measure in rice production for adapting to high-temperature conditions.However,the impact of a delayed sowing date(DS)on rice quality may vary by variety and ecological c...Adjustment of the sowing date is a widely used measure in rice production for adapting to high-temperature conditions.However,the impact of a delayed sowing date(DS)on rice quality may vary by variety and ecological conditions.In this study,we conducted experiments using four different sowing dates,the conventional sowing date 1(CS1),CS2(10 d later than CS1),DS1(30 d later than CS1),and DS2(30 d later than CS2),and three rice varieties,i.e.,Yixiangyou 2115,Fyou 498,and Chuanyou 6203.This experiment was conducted at four sites in the Sichuan Basin in 2018 and 2019 to evaluate the infuence of DS on the pasting properties of rice,which are a proxy for the eating and cooking quality(ECQ).In DS1 and DS2,the rice had a signifcantly greater amylose content(AC)but a lower protein content(PC),peak viscosity(PKV),cool paste viscosity(CPV),and hot paste viscosity(HPV)than in CS1 and CS2.Moreover,except for CS2 and DS1 in 2018,DS1 and DS2 led to 2.15-11.19%reductions in breakdown viscosity(BDV)and 23.46-108.47%increases in setback viscosity(SBV).However,the infuence of DS on rice pasting properties varied by study site and rice variety.In 2019,DS1 and DS2 led to BDV reductions of 2.35-9.33,2.61-8.61,10.03-17.78,and 2.06-8.93%,and SBV increases of 2.32-60.93,63.74-144.24,55.46-91.63,and-8.28-65.37%at the Dayi,Anzhou,Nanbu,and Shehong(except for SBV in CS2 and DS1)sites,respectively.DS resulted in greater reductions in PKV,HPV,CPV,and BDV and greater increases in the AC and SBV for Yixiangyou 2115 than for Chuanyou 6203 and Fyou 498.The correlation analysis indicated that PKV and HPV were signifcantly and positively related to the mean,maximum,and minimum temperatures after heading.These temperatures must be greater than 25.9,31.2,and 22.3℃,respectively,to increase the relative BDV and reduce the relative SBV of rice,thereby enhancing ECQ.In conclusion,DS might contribute to a signifcant deterioration in ECQ in machine-transplanted rice in the Sichuan Basin.A mean temperature above 25.9℃ after heading is required to improve the ECQ of rice.展开更多
This article investigated the factors and mechanisms that affected the workability and mechanical properties of cement paste incorporating nano-TiO_(2).The findings indicated that,for nano-TiO_(2)aqueous solution conc...This article investigated the factors and mechanisms that affected the workability and mechanical properties of cement paste incorporating nano-TiO_(2).The findings indicated that,for nano-TiO_(2)aqueous solution concentrations of 3%,6%,9%,and 12%,the optimal dispersion effect was achieved with an ultrasonic dispersion time of 20 minutes.Specifically,at a 6%nano-TiO_(2)content,both the workability and mechanical performance of the cement paste were enhanced.Furthermore,while nano-TiO_(2)did not alter the types of hydration products present in the cement paste,it did increase the amount of C-S-H gels.This enhancement was attributed to a higher number of nucleation sites for hydration products,which promoted hydration and reduced the porosity of the cement paste.展开更多
The issue of top contact in paste backfill materials is a common technical challenge in coal mine filling processes,and overcoming this problem has become a significant research direction in current studies and engine...The issue of top contact in paste backfill materials is a common technical challenge in coal mine filling processes,and overcoming this problem has become a significant research direction in current studies and engineering practices.This paper utilizes coal gangue as aggregate and hydrogen peroxide as a foaming agent to prepare foamed paste backfill materials.Three close-packing theories were employed to investigate the effects of different coal gangue particle gradations on the mechanical properties,expansion ratio,water absorption,and dry density of foamed paste backfill materials under the same foaming agent content.The hydration mechanism and pore structure evolution were analyzed using XRD,SEM,and OSM techniques.The results indicate that when the hydrogen peroxide addition is 5%,the foamed paste backfill material regulated by MAA gradation theory exhibits the best comprehensive performance,achieving a 28-day compressive strength of 0.89 MPa,an expansion ratio of 155.5%,and a dry density of 1.24 g/cm^(3).The regulation of coal gangue aggregate particle gradation not only improves the foaming efficiency but also allows the formation of CH to fill the material pores,enhancing the overall structural support capacity and forming a closer microstructure.This research provides new insights into controlling the properties of foamed paste backfill materials.展开更多
Electronic 3D printing possesses a remarkable molding ability and convenience in integrated circuits,flexible wearables,and individual automobile requirements.However,traditional 3D printing technology still struggles...Electronic 3D printing possesses a remarkable molding ability and convenience in integrated circuits,flexible wearables,and individual automobile requirements.However,traditional 3D printing technology still struggles to meet the demands of high precision and high efficiency in the process of fabricating a curved surface circuit,particularly achieving precise silver circuit molding on irregular substrates.Here,a high-precision and muti-scaled conformal manufacturing method for silver circuits is presented through the digital light processing(DLP)of ultraviolet-curable silver paste(UV-SP)with adjustable photocuring properties,enabling the successful preparation of micro-scaled conductive structure on the sharply skewed hook face.The minimum modeling depth and width of the cured silver paste can be well controlled to 10 and 88µm,respectively.Compared with traditional printing technology,the printing efficiency of complex patterns has increased by over 70%.The printed silver circuit demonstrates an exceptionally high electrical conductivity,reaching as high as 1.16×10^(7) S/m.Additionally,the UV-SP exhibits significant manufacturing efficiency and superior molding resolution compared to conventional direct ink writing and inkjet printing techniques,thereby contributing to the attainment of high precision and efficiency of conformal and micro-molding manufacturing in sensors,communication antennas,and other electronic devices based on curved substrates.展开更多
Spent lead paste(SLP)presents a major recycling challenge in lead-acid battery treatment due to its insoluble lead compounds.This study develops an innovative and environmentally sustainable approach by integrating(NH...Spent lead paste(SLP)presents a major recycling challenge in lead-acid battery treatment due to its insoluble lead compounds.This study develops an innovative and environmentally sustainable approach by integrating(NH_(4))_(2)SO_(4)-NH_(3)·H_(2)O with suspension electrolysis,effectively converting poorly soluble PbSO_(4)into soluble[Pb(NH_(3))_(4)]^(2+)complexes.The electrolytic conversion mechanisms of SLP components are systematically elucidated,revealing four distinct transformation pathways:1)metallic Pb undergoes complete dissolution as[Pb(NH_(3))_(4)]^(2+)complexes followed by cathodic reduction to elemental lead;2)PbO_(2)increases after suspension electrolysis since part of PbO is oxidized;3)PbO demonstrates dual behavior,with 45.74%undergoing anodic oxidation to PbO_(2) while the remainder(54.26%)participates in cathodic electrodeposition;4)PbSO_(4)exhibits triple conversion routes,including:1)32.98%transformation through intermediate(NH_(4))Pb(OH)SO_(4)formation followed by anodic conversion to PbO·PbSO_(4),2)21.36%direct cathodic reduction to metallic lead,and 3)the residual fraction maintaining soluble[Pb(NH_(3))_(4)]^(2+)speciation in the electrolyte.The optimized process achieves exceptional current efficiency(95.49%)and lead recovery(45.67%),with anode residues comprising 67.58%PbO_(2)and 32.42%PbO·PbSO_(4).Remarkably,this process exhibits significant economic and environmental advantages,with recycling 1 kg of SLP through the(NH_(4))_(2)SO_(4)-NH_(3)·H_(2)O suspension electrolysis process resulting in a net profit of 0.3466 USD and a reduction in carbon emissions of 119.758 kg CO_(2)eq.,offering dual advantages of environmental and economic benefits.This work provides fundamental insights into lead phase conversion during suspension electrolysis while presenting a practical,effective solution for battery recycling industries.展开更多
This research examines the impact of sulphate on pore water pressure(PWP)development in cement paste backfill(CPB)containing polycarboxylate ether(PES)superplasticizers under thermal-hydraulic-mechanical-chemical(THMC...This research examines the impact of sulphate on pore water pressure(PWP)development in cement paste backfill(CPB)containing polycarboxylate ether(PES)superplasticizers under thermal-hydraulic-mechanical-chemical(THMC)conditions that imitate actual field curing scenarios.PWP in CPB-PES,with and without sulphate,was assessed under non-isothermal field curing temperatures,varied drainage conditions,and curing stresses using a specially experimental setup.Key findings indicate that PWP behavior in CPB with PES under field conditions diverges markedly from standard laboratory conditions due to the significant effects of field curing temperatures,drainage conditions,and backfill self-weight.The study establishes that high sulphate ion concentrations notably increase initial PWP and slow its dissipation by interfering with the cement hydration process.This interference delays hydration,reduces pore water consumption,and lowers capillary pressure.Moreover,the results show that THMC conditions,especially non-isothermal field temperatures and varied drainage scenarios,considerably accelerate cement hydration compared to standard laboratory conditions,resulting in a more rapid decrease in PWP.Furthermore,improved drainage under THMC conditions mitigates the adverse effects of sulphates by facilitating sulphate ion removal,thus supporting more efficient cement hydration and CPB self-desiccation.The insights gained from this research are essential for understanding PWP behavior in sulphate-bearing CPB-PES in the field,developing predictive THMC models for backfill performance assessment,and enhancing the safety and effectiveness of mining backfills.展开更多
The stability of the“surrounding rock-backfill”com posite system is crucial for the safety of mining stopes.This study systematically investigates the effects of steel slag(SS)content and interface angle on the stre...The stability of the“surrounding rock-backfill”com posite system is crucial for the safety of mining stopes.This study systematically investigates the effects of steel slag(SS)content and interface angle on the strength and failure characteristics of rock and SS-cemented paste backfill composite specimens(RBCS)through uniaxial compression strength tests(UCS),acoustic emission systems(AE),and 3 D digital image correlation monitoring technology(3 D-DIC).The intrinsic mechanism by which SS content influences the strength of SS-CPB was revealed through an analysis of its hydration reaction degree and microstructural characteristics under varying SS content.Moreover,a theoretical strength model incorporating different interface angles was developed to explore the impact of interface inclination on failure modes and mechanical strength.The main conclusions are as follows:The incorporation of SS enhances the plastic characteristics of RBCS and reduces its brittleness,with the increase of SS content,the stress-strain curve of RBCS in the“staircase-like”stag e becomes smoother;When the interface angle is 45°,the RBCS stress-strain curve exhibits a bimodal feature,and the failure mode changes from Y-shaped fractures to interface and axial splitting;The addition of SS results in a reduction of hydration products such as Ca(OH)_(2) in the backfill cementing system and an increase in harmful pores,which weakens the bonding performance and strength of RBCS,and the SS content should not exceed 45%;As the interface angle increases,the strength of RBCS decreases,and the critical interface slip angle decreases first and then increases with the increase in the E S/E R ratio.This study provides technical references for the large-scale application of SS in mine backfill.展开更多
Using solid waste as a substitute for conventional cement has become an important way to reduce carbon emissions.This paper attempted to utilize steel slag(SS)and fly ash(FA)as supplementary cementitious material by u...Using solid waste as a substitute for conventional cement has become an important way to reduce carbon emissions.This paper attempted to utilize steel slag(SS)and fly ash(FA)as supplementary cementitious material by utilizing CO_(2)mineralization curing technology.This study examined the dominant and interactive influences of the residual water/cement ratio,CO_(2)pressure,curing time,and SS content on the mechanical properties and CO_(2)uptake rate of CO_(2)mineralization curing SS-FA-Portland cement ternary paste specimens.Additionally,microstructural development was analyzed.The findings demonstrated that each factor significantly affected compressive strength and CO_(2)uptake rate,with factor interactions becoming more pronounced at higher SS dosages(>30%),lower residual water/cement ratios(0.1-0.15),and CO_(2)pressures of 0.1-0.3 MPa.Microscopic examinations revealed that mineralization primarily yielded CaCO_(3)and silica gel.The residual w/c ratio and SS content significantly influenced the CaCO_(3)content and crystallinity of the mineralization products.Post-mineralization curing,the percentage of pores larger than 50 nm significantly decreased,the proportion of harmless pores smaller than 20 nm increased,and pore structure improved.This study also found that using CO_(2)mineralization curing SS-FA-Portland cement solid waste concrete can significantly reduce the negative impact on the environment.展开更多
The purpose of this study is to analyze the clinical effect of external application of Granulation-Promoting Jade and Red paste in the treatment of diabetic foot.This study was carried out in Pingdingshan Traditional ...The purpose of this study is to analyze the clinical effect of external application of Granulation-Promoting Jade and Red paste in the treatment of diabetic foot.This study was carried out in Pingdingshan Traditional Chinese Medicine Hospital from December 2023 to December 2024.A total of 80 patients were selected as research objects,all of whom were diagnosed diabetic foot patients.They were treated and divided into two groups based on different methods,the group names were“experimental group”and“control group”.Patients in the control group were treated with Vaseline on the basis of external treatment,and patients in the experimental group were treated with Granulation-Promoting Jade and Red paste on the basis of external treatment,and the clinical effects of different treatment methods were compared and analyzed.The results showed that the effective rate in the experimental group was significantly higher(95.00%)compared to the control group(75.00%)(P<0.05).Furthermore,the experimental group exhibited notably shorter wound healing time and granulation tissue growth time,indicating faster and better recovery(P<0.05).Additionally,post-treatment Wagner grading revealed that the proportion of patients in advanced grades(4,5,and 6)was significantly lower in the experimental group,whereas a higher proportion of patients achieved lower grades(0,1,and 2),demonstrating improved clinical outcomes(P<0.05).In conclusion,Granulation-Promoting Jade and Red Paste shows a significant therapeutic effect in treating diabetic foot,effectively promoting wound healing,improving clinical symptoms,and enhancing overall recovery.展开更多
Phosphogypsum(PG),a hard-to-dissipate by-product of the phosphorus fertilizer production industry,places strain on the biogeochemical cycles and ecosystem functions of storage sites.This pervasive problem is already w...Phosphogypsum(PG),a hard-to-dissipate by-product of the phosphorus fertilizer production industry,places strain on the biogeochemical cycles and ecosystem functions of storage sites.This pervasive problem is already widespread worldwide and requires careful stewardship.In this study,we review the presence of potentially toxic elements(PTEs)in PG and describe their associations with soil properties,anthropogenic activities,and surrounding organisms.Then,we review different ex-/in-situ solutions for promoting the sustainable management of PG,with an emphasis on in-situ cemented paste backfill,which offers a cost-effective and highly scalable opportunity to advance the value-added recovery of PG.However,concerns related to the PTEs'retention capacity and long-term effectiveness limit the implementation of this strategy.Furthermore,given that the large-scale demand for ordinary Portland cement from this conventional option has resulted in significant CO_(2) emissions,the technology has recently undergone additional scrutiny to meet the climate mitigation ambition of the Paris Agreement and China's Carbon Neutrality Economy.Therefore,we discuss the ways by which we can integrate innovative strategies,including supplementary cementitious materials,alternative binder solutions,CO_(2) mineralization,CO_(2) curing,and optimization of the supply chain for the profitability and sustainability of PG remediation.However,to maximize the co-benefits in environmental,social,and economic,future research must bridge the gap between the feasibility of expanding these advanced pathways and the multidisciplinary needs.展开更多
Utilizing delayed expansion cemented paste backfill materials(DECPB) in mine backfill operations offers an effective solution to the challenge of achieving proper contact between the in-situ cemented backfill mass and...Utilizing delayed expansion cemented paste backfill materials(DECPB) in mine backfill operations offers an effective solution to the challenge of achieving proper contact between the in-situ cemented backfill mass and the roof in mined-out areas(backfill-roof contact).This article presents recent progress in both theoretical and experimental research concerning DECPB.The types and mechanisms of expansive additives,including expansive agents,foaming agents,and expansive mineral materials relevant to DECPB,are explained,along with their impact on the expansive properties and mechanical characteristics of DECPB.The composition,material characteristics,preparation methods,and controlled release mechanisms of microcapsules are analyzed.Two methods for measuring the volume change rate of paste backfill slurries are discussed.Research indicates that an appropriate content of expansive additives not only enhances the expansive properties of cemented paste backfill materials but also contributes to improving their mechanical properties.Chemical foaming agents and bentonite are found to be more suitable for preparing DECPB compared to expansive agents.The delayed expansion of cemented paste backfill material is influenced by microcapsules,with their wall materials,preparation parameters,and the alkaline slurry environment affecting their controlled release mechanism.Developing and optimizing precise measurement devices and methods forfor the volume change rate of cemented paste backfill materials is essential requirement for studying the performance of DECPB.Combining delayed expansion technology with retarding techniques in cemented paste backfill materials can provide a reliable solution for achieving proper backfill-roof contact in the future.展开更多
During the process of constructional backfill mining,the cemented paste backfill(CPB)typically exhibits a high degree of brittleness and limited resistance to failure.In this study,the mechanical and damage evolution ...During the process of constructional backfill mining,the cemented paste backfill(CPB)typically exhibits a high degree of brittleness and limited resistance to failure.In this study,the mechanical and damage evolution characteristics of waste tire steel fiber(WTSF)-modified CPB were studied through uniaxial compression tests,acoustic emission(AE)tests,and scanning electron microscopy(SEM).The results showed that the uniaxial compressive strength(UCS)decreased when the WTSF content was 0.5%,1%,and 1.5%.When the WTSF content reached 1%,the UCS of the modified CPB exhibited a minimal decrease(0.37 MPa)compared to that without WTSF.When the WTSF content was 0.5%,1%,and 1.5%,peak strain of the WTSF-modified CPB increased by 18%,31.33%,and 81.33%,while the elastic modulus decreased by 21.31%,26.21%,and 45.42%,respectively.The addition of WTSF enhances the activity of AE events in the modified CPB,resulting in a slower progression of the entire failure process.After the failure,the modified CPB retained a certain level of load-bearing capacity.Generally,the failure of the CPB was dominated by tensile cracks.After the addition of WTSF,a gradual increase in the proportion of tensile cracks was observed upon loading the modified CPB sample to the pore compaction stage.The three-dimensional localization of AE events showed that the WTSF-modified CPB underwent progressive damage during the loading,and the samples still showed good integrity after failure.Additionally,the response relationship between energy evolution and damage development of WTSF-modified CPB during uniaxial compression was analyzed,and the damage constitutive model of CPB samples with different WTSF contents was constructed.This study provides a theoretical basis for the enhancement of CPB modified by adding WTSF,serving as a valuable reference for the design of CPB constructional backfill.展开更多
The macroscopic flow behavior and rheological properties of cemented paste backfill(CPB)are highly impacted by the inherent structure of the paste matrix.In this study,the effects of shear-induced forces and proportio...The macroscopic flow behavior and rheological properties of cemented paste backfill(CPB)are highly impacted by the inherent structure of the paste matrix.In this study,the effects of shear-induced forces and proportioning parameters on the microstructure of fresh CPB were studied.The size evolution and distribution of floc/agglomerate/particles of paste were monitored by focused beam reflection measuring(FBRM)technique,and the influencing factors of aggregation and breakage kinetics of CPB were discussed.The results indicate that influenced by both internal and external factors,the paste kinetics evolution covers the dynamic phase and the stable phase.Increasing the mass content or the cement-tailings ratio can accelerate aggregation kinetics,which is advantageous for the rise of average floc size.Besides,the admixture and high shear can improve breaking kinetics,which is beneficial to reduce the average floc size.The chord length resembles a normal distribution somewhat,with a peak value of approximate 20μm.The particle disaggregation con-stant(k_(2))is positively correlated with the agitation rate,and k_(2) is five orders of magnitude greater than the particle aggregation constant(k1).The kinetics model depicts the evolution law of particles over time quantitatively and provides a theoretical foundation for the micromechanics of complicated rheological behavior of paste.展开更多
文摘Chemically precipitated β type nickel hydroxide powder was surface modified by electroless deposition of Co Zn coatings,and physical properties of both the modified and unmodified nickel hydroxide were characterized by scanning electron microscopy (SEM), specific surface area (BET), X ray diffraction (XRD) and X ray photoelectron spectroscopy (XPS). It has been found that Co and Zn components of the surface electroless coatings exist in the oxidized state. Electrochemical performances of pasted nickel electrodes using the modified nickel hydroxide as an active material were investigated, and compared with those of the electrodes prepared with the unmodified nickel hydroxide. Charge/discharge tests show that the modified nickel hydroxide electrodes exhibit better performances in the charge efficiency, specific discharge capacity and active material utilization. Their resistance to swelling with cycling is also superior to that of the unmodified nickel hydroxide electrodes. Cyclic voltammetric (CV) studies indicate that the modified electrodes have a higher electrochemical activity, and the porous pasted nickel electrodes have some distinguished CV characteristics in comparison with those of the thin film nickel electrodes.
基金Supported by Yunnan Major Scientific and Technological Projects(No.202403AA080001)National Natural Science Foundation of China(No.52074137)Yunnan Fundamental Research Projects(No.202201AT070151)。
文摘Three types of activators such as sodium hydroxide,calcium oxide and triethanolamine(TEA)are used to establish different activation environments to address the problems associated with the process of activating fly ash paste.We conducted mechanical tests and numerical simulations to understand the evolution of microstructure,and used environmental scanning electron microscopy(ESEM)and energy dispersive spectroscopy(EDS)techniques to analyze the microenvironments of the samples.The mechanical properties of fly ash paste under different activation conditions and the changes in the microstructure and composition were investigated.The results revealed that under conditions of low NaOH content(1%-3%),the strength of the sample increased significantly.When the content exceeded 4%,the rate of increase in strength decreased.Based on the results,the optimal NaOH content was identified,which was about 4%.A good activation effect,especially for short-term activation(3-7 d),was achieved using TEA under high doping conditions.The activation effect was poor for long-term strength after 28 days.The CaO content did not significantly affect the degree of activation achieved.The maximum effect was exerted when the content of CaO was 2%.The virtual cement and concrete testing laboratory(VCCTL)was used to simulate the hydration process,and the results revealed that the use of the three types of activators accelerated the formation of Ca(OH)_(2) in the system.The activators also corroded the surface of the fly ash particles,resulting in a pozzolanic reaction.The active substances in fly ash were released efficiently,and hydration was realized.The pores were filled with hydration products,and the microstructure changed to form a new frame of paste filling that helped improve the strength of fly ash paste.
文摘Introduction The widespread use of cement in concrete leads to increased carbon emissions,so the demand for supplementary cementitious materials increases significantly.Limestone powder and steel slag powder are widely used as supplementary cementitious materials in modern concrete.However,for UHPC and self-compacting concrete,an extremely low water/binder(W/B)ratio is on one hand a key factor in achieving ultra-high strength and ultra-low porosity of the materials,on the other hand,also leads to the deterioration of the rheological properties of the fresh paste.Meanwhile,the existing researches focus on the influence of single limestone powder or steel slag powder on the mechanical properties or microstructure of cement-based materials.Little work on the influence of steel slag powder or limestone powder on the rheological properties of composite paste at an extremely low water/binder ratio has been investigated quantitatively.The mechanism of the effect of steel slag powder or limestone powder on the rheological properties of composite paste at extremely low water/binder ratios is still unclear.In this work,the effects of steel slag powder and limestone powder on the rheological properties of composite paste at different low water/binder ratios were analyzed via determining the flow diameter,setting time,marsh cone flow time,rheological parameters,and total organic carbon content.Methods A composite paste was prepared with P.I 42.5 ordinary Portland cement,steel slag powder,limestone powder,blast furnace slag and silica fume as raw materials in a certain proportion.To achieve the preparation of composite paste with extremely low water/binder ratios,a polycarboxylate superplasticizer with a water/reducing rate of 40%(Jiangsu Subot New Materials Co.,Ltd.,China)was used.The dosage of polycarboxylate superplasticizer for the composite paste with different water/binder ratios of 0.16 and 0.21 was 2%and 0.8%,respectively.Composite pastes with different proportions of steel slag powder or limestone powder at water/binder ratios of 0.16 and 0.21 were prepared.The flow diameter(i.e.,the larger the flow diameter,the better the fluidity),setting time(i.e.,the time when the fluidity is lost)and marsh cone flow time(i.e.,the shorter the flow time,the better the fluidity)were determined to analyze the fluidity of the composite pastes.the rheological properties of composite paste at a water/binder ratio of 0.16 for rheological properties tests were determined,and the rheological parameters were obtained by the H-B model.The adsorption performance of the polycarboxylate superplasticizer was analyzed by testing the TOC content.Results and discussion When the ratio of water/binder is 0.16,both limestone powder and steel slag powder initially increase the flow diameter of the composite paste.However,the fluidity of the composite paste decreases over time,and the reduction is more pronounced with steel slag powder.This is because the nucleation and hydration promotion effect of limestone powder can reduce the loss rate of flow diameter,while the rough particles of steel slag powder increase the internal friction force,resulting in a decrease in the flow diameter of composite paste.Adding limestone powder and steel slag powder both shortens the setting time and marsh cone flow time of the composite paste.However,the steel slag powder addition of 30%delays the final setting time due to its delaying effect.Also,limestone powder can enhance the thixotropy and reduce the yield stress and plastic viscosity,thereby improving the rheological properties.In contrast,steel slag powder can increase the yield stress and plastic viscosity,thereby weakening the rheological properties and thixotropy.Steel slag powder and limestone powder both can enhance the adsorption effect of polycarboxylate superplasticizer.Steel slag powder has a stronger adsorption effect.The composite paste containing limestone powder has a higher free water content.This is because the rough and porous surface of steel slag itself and the uneven particle shape lead to the physical adsorption of polycarboxylate superplasticizer molecules on the surface of steel slag particles,thereby reducing the effective content of the water reducer dispersion.Increasing the water/binder ratio to 0.21 results in a decrease in the flow diameter of the composite paste.Furthermore,the setting time and marsh cone flow time can prolong due to the reduction in the dosage of polycarboxylate superplasticizer.Conclusions The results showed that the fluidity loss rate of composite paste with limestone powder could be lower than that of composite paste with steel slag powder.Compared to steel slag powder,the addition of limestone powder reduced the setting time and marsh cone flow time of the composite paste.The addition of limestone powder could shorten the yield stress and plastic viscosity of the composite paste.Therefore,the composite paste with limestone powder had better rheological properties and stronger thixotropy rather than that with steel slag powder.The addition of limestone powder could improve the rheological properties of the composite paste.Compared to composite paste with limestone powder,a better adsorption effect of polycarboxylate superplasticizer on the surface of the composite binder with steel slag powder could be obtained.The free water content of the composite paste with limestone powder was still higher than that of the composite paste with steel slag powder.The fluidity and rheological properties of the composite paste with limestone powder could be better.The comprehensive analysis indicated that a positive effect of limestone powder on rheological properties of composite paste at an extremely low water/binder ratio could be more dominant than that of steel slag powder.
基金Science and Technology Achievements Transformation Project of the Autonomous Prefecture(Project No.:202401)National College Students'Innovation and Entrepreneurship Training Program(Project Title:"Li Zhiyun·Ku Li Chun"-Pioneer in Promoting National Geographic Brand,Project Number:202513561005).
文摘Pear paste is a traditional preparation with both medicinal and nutritional functions.The“pear”,as its core ingredient,plays a crucial role in the efficacy of the preparation.This paper,through the interdisciplinary integration of evidence from traditional Chinese medicine,food chemistry,molecular biology,and clinical medicine,constructs a complete“raw material-component transformation-biological regulation”model for the first time.It is found that in pear paste,pears not only serve as a functional matrix.The polysaccharide-polyphenol-triterpene complex system forms a multi-target cough-relieving and anti-inflammatory network through dual regulation of TRPV1/TRPA1 ion channels,inhibition of the NLRP3 inflammasome,and metabolites of gut microbiota such as SCFAs.The research results provide a theoretical breakthrough for the modern development of pear paste and a scientific basis for the modernization of traditional preparations.
文摘Aceh in Indonesia is rich inmarine resources and abundant fishery products such as oyster.Traditionally,fishermen only harvest oysters and discard the shells,which can cause pollution and environmental contamination.Waste Oyster Shells(WOS)contain a high percentage of calcium carbonate(CaCO_(3))that experiences thermal decomposition at high temperature,following the reaction CaCO_(3)→CaO+CO_(2)(ΔT=825℃).At temperature>900℃,dead-burned lime is formed,which severely influences CaO reactivity.However,the optimum temperature for producing high CaO content is still uncertain.Therefore,this study aimed to determine the optimum calcination temperature to produce high CaO content,assess initial setting time of WOS paste,and identify the best compressive strength of paste.For the experiment,WOS was used as a partial cement replacement(with a size of 0.075 mm)in paste at a proportion of 5%and calcined at temperature of 700℃,800℃,900℃,and 1000℃.The specimens used were an ebonite ring(dimensions:70 mm bottom diameter,60 mm top diameter,and 40 mm height)and a cube(dimensions:5 cm×5 cm×5 cm).The experiment was conducted following the ASTM(American Society for Testing andMaterials)standards and optimumcompressive strength values were analyzed using ANOVA(Analysis of Variance)and Response Surface Methodology(RSM)through the Design Expert software.The results showed that WOS calcined at 1000℃ increased CaO content by approximately 57.40%.Furthermore,the initial setting time test of 5%WOS paste at 1000℃ showed a more uniform binding performance compared to conventional cement paste,with an initial setting time of 75 min and a penetration depth of 15 mm.In line with the analysis,optimum compressive strength of 71.028 MPa with a desirability value of 0.986 was achieved at 5%cement replacement and calcination temperature of 786.44℃.
基金funded by the National Natural Science Foundation of China(Grant 42177164)the Distinguished Youth Science Foundation of Hunan Province of China(2022JJ10073)supported by China Scholarship Council with the grant number of 202006370006.
文摘With the growing demand for sustainable development in the mining industry,cemented paste backfill(CPB)materials,primarily composed of tailings,play a crucial role in mine backfilling and underground support systems.To enhance the mechanical properties of CPB materials,fiber reinforcement technology has gradually gained attention,though challenges remain in predicting its performance.This study develops a hybrid model based on the adaptive equilibrium optimizer(adap-EO)-enhanced XGBoost method for accurately predicting the uniaxial compressive strength of fiber-reinforced CPB.Through systematic comparison with various other machine learning methods,results demonstrate that the proposed hybridmodel exhibits excellent predictive performance on the test set,achieving a coefficient of determination(R^(2))of 0.9675,root mean square error(RMSE)of 0.6084,and mean absolute error(MAE)of 0.4620.Input importance analysis reveals that cement-tailings ratio,curing time,and concentration are the three most critical factors affectingmaterial strength,with cement-tailings ratio showing a positive correlation with strength,concentrations above 70% significantly improvingmaterial strength,and curing periods beyond 28 days being essential for strength development.Fiber parameters contribute secondarily but notably to material strength,with fiber length exhibiting an optimal range of approximately 12 mm.This study not only provides a high-precision strength prediction model but also reveals the inherent correlations between various parameters and material performance,offering scientific basis for mixture optimization and engineering applications of fiber-reinforced CPB materials.
基金Funded by the Deep Underground National Science&Technology Major Project gram of China(No.2024ZD1003704)the National Natural Science Foundation of China(Nos.51834001 and 52374111)。
文摘The multi-objective optimization of backfill effect based on response surface methodology and desirability function(RSM-DF)was conducted.Firstly,the test results show that the uniaxial compressive strength(UCS)increases with cement sand ratio(CSR),slurry concentration(SC),and curing age(CA),while flow resistance(FR)increases with SC and backfill flow rate(BFR),and decreases with CSR.Then the regression models of UCS and FR as response values were established through RSM.Multi-factor interaction found that CSR-CA impacted UCS most,while SC-BFR impacted FR most.By introducing the desirability function,the optimal backfill parameters were obtained based on RSM-DF(CSR is 1:6.25,SC is 69%,CA is 11.5 d,and BFR is 90 m^(3)/h),showing close results of Design Expert and high reliability for optimization.For a copper mine in China,RSM-DF optimization will reduce cement consumption by 4758 t per year,increase tailings consumption by about 6700 t,and reduce CO_(2)emission by about 4758 t.Thus,RSM-DF provides a new approach for backfill parameters optimization,which has important theoretical and practical values.
基金supported by the National Natural Science Foundation of China(U20A2022 and 32372217)the National Key Research and Development Program of China(2022YFD2300700)the Free Exploration Program of State Key Laboratory of Crop Gene Exploration and Utilization in Sichuan Basin,China(SKL-ZY202216)。
文摘Adjustment of the sowing date is a widely used measure in rice production for adapting to high-temperature conditions.However,the impact of a delayed sowing date(DS)on rice quality may vary by variety and ecological conditions.In this study,we conducted experiments using four different sowing dates,the conventional sowing date 1(CS1),CS2(10 d later than CS1),DS1(30 d later than CS1),and DS2(30 d later than CS2),and three rice varieties,i.e.,Yixiangyou 2115,Fyou 498,and Chuanyou 6203.This experiment was conducted at four sites in the Sichuan Basin in 2018 and 2019 to evaluate the infuence of DS on the pasting properties of rice,which are a proxy for the eating and cooking quality(ECQ).In DS1 and DS2,the rice had a signifcantly greater amylose content(AC)but a lower protein content(PC),peak viscosity(PKV),cool paste viscosity(CPV),and hot paste viscosity(HPV)than in CS1 and CS2.Moreover,except for CS2 and DS1 in 2018,DS1 and DS2 led to 2.15-11.19%reductions in breakdown viscosity(BDV)and 23.46-108.47%increases in setback viscosity(SBV).However,the infuence of DS on rice pasting properties varied by study site and rice variety.In 2019,DS1 and DS2 led to BDV reductions of 2.35-9.33,2.61-8.61,10.03-17.78,and 2.06-8.93%,and SBV increases of 2.32-60.93,63.74-144.24,55.46-91.63,and-8.28-65.37%at the Dayi,Anzhou,Nanbu,and Shehong(except for SBV in CS2 and DS1)sites,respectively.DS resulted in greater reductions in PKV,HPV,CPV,and BDV and greater increases in the AC and SBV for Yixiangyou 2115 than for Chuanyou 6203 and Fyou 498.The correlation analysis indicated that PKV and HPV were signifcantly and positively related to the mean,maximum,and minimum temperatures after heading.These temperatures must be greater than 25.9,31.2,and 22.3℃,respectively,to increase the relative BDV and reduce the relative SBV of rice,thereby enhancing ECQ.In conclusion,DS might contribute to a signifcant deterioration in ECQ in machine-transplanted rice in the Sichuan Basin.A mean temperature above 25.9℃ after heading is required to improve the ECQ of rice.
基金Funded by National Natural Science Foundation of China(No.52108188)State Key Laboratory of Silicate Materials for Architectures(Wuhan University of Technology)(No.SYSJJ2024-15)+3 种基金State Key Laboratory of Mountain Bridge and Tunnel Engineering,Chongqing Jiaotong University(No.SKLBT-2301)Opening Project of State Key Laboratory of Green Building Materials(No.2022GBM10)Open Research Fund of Key Laboratory of Engineering Materials of Ministry of Water Resources,China Institute of Water Resources and Hydropower Research(No.EMF202407)General Project of Science and Technology Plan of Beijing Municipal Commission of Education(No.KM202110005018)。
文摘This article investigated the factors and mechanisms that affected the workability and mechanical properties of cement paste incorporating nano-TiO_(2).The findings indicated that,for nano-TiO_(2)aqueous solution concentrations of 3%,6%,9%,and 12%,the optimal dispersion effect was achieved with an ultrasonic dispersion time of 20 minutes.Specifically,at a 6%nano-TiO_(2)content,both the workability and mechanical performance of the cement paste were enhanced.Furthermore,while nano-TiO_(2)did not alter the types of hydration products present in the cement paste,it did increase the amount of C-S-H gels.This enhancement was attributed to a higher number of nucleation sites for hydration products,which promoted hydration and reduced the porosity of the cement paste.
基金National Natural Science Foundation of China(Project No.:U1905216).
文摘The issue of top contact in paste backfill materials is a common technical challenge in coal mine filling processes,and overcoming this problem has become a significant research direction in current studies and engineering practices.This paper utilizes coal gangue as aggregate and hydrogen peroxide as a foaming agent to prepare foamed paste backfill materials.Three close-packing theories were employed to investigate the effects of different coal gangue particle gradations on the mechanical properties,expansion ratio,water absorption,and dry density of foamed paste backfill materials under the same foaming agent content.The hydration mechanism and pore structure evolution were analyzed using XRD,SEM,and OSM techniques.The results indicate that when the hydrogen peroxide addition is 5%,the foamed paste backfill material regulated by MAA gradation theory exhibits the best comprehensive performance,achieving a 28-day compressive strength of 0.89 MPa,an expansion ratio of 155.5%,and a dry density of 1.24 g/cm^(3).The regulation of coal gangue aggregate particle gradation not only improves the foaming efficiency but also allows the formation of CH to fill the material pores,enhancing the overall structural support capacity and forming a closer microstructure.This research provides new insights into controlling the properties of foamed paste backfill materials.
基金supported by the National Natural Science Foundation of China(Nos.51972079 and 52302062)the National Key Research and Development Program of China(Nos.2022YFB370630202 and 2022YFB3706305).
文摘Electronic 3D printing possesses a remarkable molding ability and convenience in integrated circuits,flexible wearables,and individual automobile requirements.However,traditional 3D printing technology still struggles to meet the demands of high precision and high efficiency in the process of fabricating a curved surface circuit,particularly achieving precise silver circuit molding on irregular substrates.Here,a high-precision and muti-scaled conformal manufacturing method for silver circuits is presented through the digital light processing(DLP)of ultraviolet-curable silver paste(UV-SP)with adjustable photocuring properties,enabling the successful preparation of micro-scaled conductive structure on the sharply skewed hook face.The minimum modeling depth and width of the cured silver paste can be well controlled to 10 and 88µm,respectively.Compared with traditional printing technology,the printing efficiency of complex patterns has increased by over 70%.The printed silver circuit demonstrates an exceptionally high electrical conductivity,reaching as high as 1.16×10^(7) S/m.Additionally,the UV-SP exhibits significant manufacturing efficiency and superior molding resolution compared to conventional direct ink writing and inkjet printing techniques,thereby contributing to the attainment of high precision and efficiency of conformal and micro-molding manufacturing in sensors,communication antennas,and other electronic devices based on curved substrates.
基金sponsored by the National Natural Science Foundation of China(No.22276153).The authors would like to thank the Shiyanjia Lab for the XRD test.
文摘Spent lead paste(SLP)presents a major recycling challenge in lead-acid battery treatment due to its insoluble lead compounds.This study develops an innovative and environmentally sustainable approach by integrating(NH_(4))_(2)SO_(4)-NH_(3)·H_(2)O with suspension electrolysis,effectively converting poorly soluble PbSO_(4)into soluble[Pb(NH_(3))_(4)]^(2+)complexes.The electrolytic conversion mechanisms of SLP components are systematically elucidated,revealing four distinct transformation pathways:1)metallic Pb undergoes complete dissolution as[Pb(NH_(3))_(4)]^(2+)complexes followed by cathodic reduction to elemental lead;2)PbO_(2)increases after suspension electrolysis since part of PbO is oxidized;3)PbO demonstrates dual behavior,with 45.74%undergoing anodic oxidation to PbO_(2) while the remainder(54.26%)participates in cathodic electrodeposition;4)PbSO_(4)exhibits triple conversion routes,including:1)32.98%transformation through intermediate(NH_(4))Pb(OH)SO_(4)formation followed by anodic conversion to PbO·PbSO_(4),2)21.36%direct cathodic reduction to metallic lead,and 3)the residual fraction maintaining soluble[Pb(NH_(3))_(4)]^(2+)speciation in the electrolyte.The optimized process achieves exceptional current efficiency(95.49%)and lead recovery(45.67%),with anode residues comprising 67.58%PbO_(2)and 32.42%PbO·PbSO_(4).Remarkably,this process exhibits significant economic and environmental advantages,with recycling 1 kg of SLP through the(NH_(4))_(2)SO_(4)-NH_(3)·H_(2)O suspension electrolysis process resulting in a net profit of 0.3466 USD and a reduction in carbon emissions of 119.758 kg CO_(2)eq.,offering dual advantages of environmental and economic benefits.This work provides fundamental insights into lead phase conversion during suspension electrolysis while presenting a practical,effective solution for battery recycling industries.
文摘This research examines the impact of sulphate on pore water pressure(PWP)development in cement paste backfill(CPB)containing polycarboxylate ether(PES)superplasticizers under thermal-hydraulic-mechanical-chemical(THMC)conditions that imitate actual field curing scenarios.PWP in CPB-PES,with and without sulphate,was assessed under non-isothermal field curing temperatures,varied drainage conditions,and curing stresses using a specially experimental setup.Key findings indicate that PWP behavior in CPB with PES under field conditions diverges markedly from standard laboratory conditions due to the significant effects of field curing temperatures,drainage conditions,and backfill self-weight.The study establishes that high sulphate ion concentrations notably increase initial PWP and slow its dissipation by interfering with the cement hydration process.This interference delays hydration,reduces pore water consumption,and lowers capillary pressure.Moreover,the results show that THMC conditions,especially non-isothermal field temperatures and varied drainage scenarios,considerably accelerate cement hydration compared to standard laboratory conditions,resulting in a more rapid decrease in PWP.Furthermore,improved drainage under THMC conditions mitigates the adverse effects of sulphates by facilitating sulphate ion removal,thus supporting more efficient cement hydration and CPB self-desiccation.The insights gained from this research are essential for understanding PWP behavior in sulphate-bearing CPB-PES in the field,developing predictive THMC models for backfill performance assessment,and enhancing the safety and effectiveness of mining backfills.
基金Project(52308316)supported by the National Natural Science Foundation of China,Project(BBJ2024088)supported by the Fundamental Research Funds for the Central Universities(PhD.Top Innovative Talents Fund of CUMTB),China。
文摘The stability of the“surrounding rock-backfill”com posite system is crucial for the safety of mining stopes.This study systematically investigates the effects of steel slag(SS)content and interface angle on the strength and failure characteristics of rock and SS-cemented paste backfill composite specimens(RBCS)through uniaxial compression strength tests(UCS),acoustic emission systems(AE),and 3 D digital image correlation monitoring technology(3 D-DIC).The intrinsic mechanism by which SS content influences the strength of SS-CPB was revealed through an analysis of its hydration reaction degree and microstructural characteristics under varying SS content.Moreover,a theoretical strength model incorporating different interface angles was developed to explore the impact of interface inclination on failure modes and mechanical strength.The main conclusions are as follows:The incorporation of SS enhances the plastic characteristics of RBCS and reduces its brittleness,with the increase of SS content,the stress-strain curve of RBCS in the“staircase-like”stag e becomes smoother;When the interface angle is 45°,the RBCS stress-strain curve exhibits a bimodal feature,and the failure mode changes from Y-shaped fractures to interface and axial splitting;The addition of SS results in a reduction of hydration products such as Ca(OH)_(2) in the backfill cementing system and an increase in harmful pores,which weakens the bonding performance and strength of RBCS,and the SS content should not exceed 45%;As the interface angle increases,the strength of RBCS decreases,and the critical interface slip angle decreases first and then increases with the increase in the E S/E R ratio.This study provides technical references for the large-scale application of SS in mine backfill.
基金Project(52479115)supported by the National Natural Science Foundation of ChinaProject(2024SF-YBXM-615)supported by the Key Research and Development Program of Shaanxi Province,China+1 种基金Project(2022943)supported by the Youth Innovation Team of Shaanxi Universities,ChinaProject(300102283721)supported by the Fundamental Research Funds for the Central Universities,China。
文摘Using solid waste as a substitute for conventional cement has become an important way to reduce carbon emissions.This paper attempted to utilize steel slag(SS)and fly ash(FA)as supplementary cementitious material by utilizing CO_(2)mineralization curing technology.This study examined the dominant and interactive influences of the residual water/cement ratio,CO_(2)pressure,curing time,and SS content on the mechanical properties and CO_(2)uptake rate of CO_(2)mineralization curing SS-FA-Portland cement ternary paste specimens.Additionally,microstructural development was analyzed.The findings demonstrated that each factor significantly affected compressive strength and CO_(2)uptake rate,with factor interactions becoming more pronounced at higher SS dosages(>30%),lower residual water/cement ratios(0.1-0.15),and CO_(2)pressures of 0.1-0.3 MPa.Microscopic examinations revealed that mineralization primarily yielded CaCO_(3)and silica gel.The residual w/c ratio and SS content significantly influenced the CaCO_(3)content and crystallinity of the mineralization products.Post-mineralization curing,the percentage of pores larger than 50 nm significantly decreased,the proportion of harmless pores smaller than 20 nm increased,and pore structure improved.This study also found that using CO_(2)mineralization curing SS-FA-Portland cement solid waste concrete can significantly reduce the negative impact on the environment.
基金Special Research Project of Traditional Chinese Medicine in Henan Province(Project No.:2022ZY1191)。
文摘The purpose of this study is to analyze the clinical effect of external application of Granulation-Promoting Jade and Red paste in the treatment of diabetic foot.This study was carried out in Pingdingshan Traditional Chinese Medicine Hospital from December 2023 to December 2024.A total of 80 patients were selected as research objects,all of whom were diagnosed diabetic foot patients.They were treated and divided into two groups based on different methods,the group names were“experimental group”and“control group”.Patients in the control group were treated with Vaseline on the basis of external treatment,and patients in the experimental group were treated with Granulation-Promoting Jade and Red paste on the basis of external treatment,and the clinical effects of different treatment methods were compared and analyzed.The results showed that the effective rate in the experimental group was significantly higher(95.00%)compared to the control group(75.00%)(P<0.05).Furthermore,the experimental group exhibited notably shorter wound healing time and granulation tissue growth time,indicating faster and better recovery(P<0.05).Additionally,post-treatment Wagner grading revealed that the proportion of patients in advanced grades(4,5,and 6)was significantly lower in the experimental group,whereas a higher proportion of patients achieved lower grades(0,1,and 2),demonstrating improved clinical outcomes(P<0.05).In conclusion,Granulation-Promoting Jade and Red Paste shows a significant therapeutic effect in treating diabetic foot,effectively promoting wound healing,improving clinical symptoms,and enhancing overall recovery.
基金the National Natural Science Foundation of China(Nos.552104156,52074351,and 52004330)the National Natural Science Foundation of Hunan Province,China(No.2022JJ30714)the Science and Technology Innovation Program of Hunan Province,China(No.2021RC3125)。
文摘Phosphogypsum(PG),a hard-to-dissipate by-product of the phosphorus fertilizer production industry,places strain on the biogeochemical cycles and ecosystem functions of storage sites.This pervasive problem is already widespread worldwide and requires careful stewardship.In this study,we review the presence of potentially toxic elements(PTEs)in PG and describe their associations with soil properties,anthropogenic activities,and surrounding organisms.Then,we review different ex-/in-situ solutions for promoting the sustainable management of PG,with an emphasis on in-situ cemented paste backfill,which offers a cost-effective and highly scalable opportunity to advance the value-added recovery of PG.However,concerns related to the PTEs'retention capacity and long-term effectiveness limit the implementation of this strategy.Furthermore,given that the large-scale demand for ordinary Portland cement from this conventional option has resulted in significant CO_(2) emissions,the technology has recently undergone additional scrutiny to meet the climate mitigation ambition of the Paris Agreement and China's Carbon Neutrality Economy.Therefore,we discuss the ways by which we can integrate innovative strategies,including supplementary cementitious materials,alternative binder solutions,CO_(2) mineralization,CO_(2) curing,and optimization of the supply chain for the profitability and sustainability of PG remediation.However,to maximize the co-benefits in environmental,social,and economic,future research must bridge the gap between the feasibility of expanding these advanced pathways and the multidisciplinary needs.
基金financially supported by the National Natural Science Foundation of China (No.52274122)the Research Fund of BGRIMM Technology Group (No.02-2136)the Youth Innovation Fund of BGRIMM Technology Group (Nos.04-2306,04-2342 and 04-2208)。
文摘Utilizing delayed expansion cemented paste backfill materials(DECPB) in mine backfill operations offers an effective solution to the challenge of achieving proper contact between the in-situ cemented backfill mass and the roof in mined-out areas(backfill-roof contact).This article presents recent progress in both theoretical and experimental research concerning DECPB.The types and mechanisms of expansive additives,including expansive agents,foaming agents,and expansive mineral materials relevant to DECPB,are explained,along with their impact on the expansive properties and mechanical characteristics of DECPB.The composition,material characteristics,preparation methods,and controlled release mechanisms of microcapsules are analyzed.Two methods for measuring the volume change rate of paste backfill slurries are discussed.Research indicates that an appropriate content of expansive additives not only enhances the expansive properties of cemented paste backfill materials but also contributes to improving their mechanical properties.Chemical foaming agents and bentonite are found to be more suitable for preparing DECPB compared to expansive agents.The delayed expansion of cemented paste backfill material is influenced by microcapsules,with their wall materials,preparation parameters,and the alkaline slurry environment affecting their controlled release mechanism.Developing and optimizing precise measurement devices and methods forfor the volume change rate of cemented paste backfill materials is essential requirement for studying the performance of DECPB.Combining delayed expansion technology with retarding techniques in cemented paste backfill materials can provide a reliable solution for achieving proper backfill-roof contact in the future.
基金financially supported by the National Natural Science Foundation of China(Nos.52274143 and 51874284).
文摘During the process of constructional backfill mining,the cemented paste backfill(CPB)typically exhibits a high degree of brittleness and limited resistance to failure.In this study,the mechanical and damage evolution characteristics of waste tire steel fiber(WTSF)-modified CPB were studied through uniaxial compression tests,acoustic emission(AE)tests,and scanning electron microscopy(SEM).The results showed that the uniaxial compressive strength(UCS)decreased when the WTSF content was 0.5%,1%,and 1.5%.When the WTSF content reached 1%,the UCS of the modified CPB exhibited a minimal decrease(0.37 MPa)compared to that without WTSF.When the WTSF content was 0.5%,1%,and 1.5%,peak strain of the WTSF-modified CPB increased by 18%,31.33%,and 81.33%,while the elastic modulus decreased by 21.31%,26.21%,and 45.42%,respectively.The addition of WTSF enhances the activity of AE events in the modified CPB,resulting in a slower progression of the entire failure process.After the failure,the modified CPB retained a certain level of load-bearing capacity.Generally,the failure of the CPB was dominated by tensile cracks.After the addition of WTSF,a gradual increase in the proportion of tensile cracks was observed upon loading the modified CPB sample to the pore compaction stage.The three-dimensional localization of AE events showed that the WTSF-modified CPB underwent progressive damage during the loading,and the samples still showed good integrity after failure.Additionally,the response relationship between energy evolution and damage development of WTSF-modified CPB during uniaxial compression was analyzed,and the damage constitutive model of CPB samples with different WTSF contents was constructed.This study provides a theoretical basis for the enhancement of CPB modified by adding WTSF,serving as a valuable reference for the design of CPB constructional backfill.
基金financially supported by the National Natural Science Foundation of China(No.52104129)the Shandong Provincial Major Science and Technology Innovation Project,China(No.2019SDZY05)+2 种基金the key Laboratory of Mine Ecological Effects and Systematic Restoration,Ministry of Natural Resources(No.MEER-2022-09)the Double First-class Construction Project in Henan Province,China(No.AQ20230735)the Doctoral Fund of Henan Polytechnic University(No.B2021-59).
文摘The macroscopic flow behavior and rheological properties of cemented paste backfill(CPB)are highly impacted by the inherent structure of the paste matrix.In this study,the effects of shear-induced forces and proportioning parameters on the microstructure of fresh CPB were studied.The size evolution and distribution of floc/agglomerate/particles of paste were monitored by focused beam reflection measuring(FBRM)technique,and the influencing factors of aggregation and breakage kinetics of CPB were discussed.The results indicate that influenced by both internal and external factors,the paste kinetics evolution covers the dynamic phase and the stable phase.Increasing the mass content or the cement-tailings ratio can accelerate aggregation kinetics,which is advantageous for the rise of average floc size.Besides,the admixture and high shear can improve breaking kinetics,which is beneficial to reduce the average floc size.The chord length resembles a normal distribution somewhat,with a peak value of approximate 20μm.The particle disaggregation con-stant(k_(2))is positively correlated with the agitation rate,and k_(2) is five orders of magnitude greater than the particle aggregation constant(k1).The kinetics model depicts the evolution law of particles over time quantitatively and provides a theoretical foundation for the micromechanics of complicated rheological behavior of paste.
