Developing the railway transport sector is a challenging scientific,economic and social research topic starting with ensuring human security.The main topic that should be developed in that sense is the ballast stabili...Developing the railway transport sector is a challenging scientific,economic and social research topic starting with ensuring human security.The main topic that should be developed in that sense is the ballast stability and dynamical behaviour under external loading and environmental changes.This paper investigates the effect of particle size distribution and normal pressure on the mechanical response of a ballast bed.Grading curves of ballast layers with different sizes are illustrated to discuss their strength behaviour under various strains to deduce the significant effect on the direct shear performance of the ballast layer.Direct shear tests with different Particle Size Distribution(PSD)were reproduced using the Discrete Element Method(DEM).It is noticed that when the number of small-sized ballast increases,the shear strength and the friction angle increase to varying degrees under different normal pressures,with an average increase of 27%and 8%,respectively.When the number of large-sized ballast decreases,the shear strength and the friction angle decrease to varying degrees under different normal pressures,with an average decrease of 6%and 3%,respectively.展开更多
This work used 5CrMnMo steel and titanium carbide(TiC)powders to fabricate particulate metal matrix composites(PMMCS).The composites’microstructure,hardness,and impact toughness were compared with four different tita...This work used 5CrMnMo steel and titanium carbide(TiC)powders to fabricate particulate metal matrix composites(PMMCS).The composites’microstructure,hardness,and impact toughness were compared with four different titanium carbide ceramic particle sizes.The phase composition and microstructure of composites were studied.Vickers hardness and Charpy impact tests were employed to analyze composites’hardness and impact ductility,respectively.The results showed that the four groups of composites are mainly composed of martensite,trace residual austenite,and titanium carbide(undissolved TiC and primary TiC particles).With the growth of the ceramic particle dimension in the composite layer,the number of primary titanium carbide ceramics gradually decreased.When the initial ceramic particle size was small,it tended to generate dendritic primary TiC,and when the particle size was large,it tended to generate polygons and ellipsoids.Furthermore,with the growth of titanium carbide ceramic particle dimension in the composites,the hardness of the composites decreased but the impact toughness of the composites rose first and then descended.When the ceramic particle size was 50-75μm,the composite had the highest hardness,and the impact energy of the composites was the highest,which is 8 J.This was because there were more undissolved titanium carbide ceramics in the composite,and there was a thicker matrix metal between the ceramic particles.展开更多
The increased risk of chronic diseases has led to increasing importance of coarse foods in daily life,but the inclusion of new ingredients has a great degree of influence on the structural characteristics and sensory ...The increased risk of chronic diseases has led to increasing importance of coarse foods in daily life,but the inclusion of new ingredients has a great degree of influence on the structural characteristics and sensory qualities of the food.The effects of five different particle size variations on the physicochemical characteristics,dough,and steamed bread structure of Flaxseed-based milk coproduct(FMC)were investigated.As the particle size decreases,the structure of the dough becomes denser due to an increase in water retention capacity and dissolution capacity,weakening the competition for dough moisture and allowing for an increase in air-holding capacity.The reduction in particle size increased the specific volume of the steamed bread,a decrease in the spread ratio,and an optimization of hardness and elasticity,as well as an increase in consumer acceptance of the FMC steamed bread.However,it is not the smaller the particle size,the higher the quality of steamed bread,appropriate reduction of particle size can improve the quality of steamed bread.In addition,the addition of FMC reduces fat digestion.Therefore,the present study proposes a method to change the particle size of FMC to optimize the quality of the steamed bread and to reduce fat digestibility by adding FMC.展开更多
A feasible criterion was established to determine the lower size limit of raw coal(d_(pRm))for efficient beneficiation in the air-fluidized bed with magnetite particles.The feasibility of using small magnetite particl...A feasible criterion was established to determine the lower size limit of raw coal(d_(pRm))for efficient beneficiation in the air-fluidized bed with magnetite particles.The feasibility of using small magnetite particles to accommodate the fine raw coal was demonstrated from the experimental perspective.The minimum size for the magnetite particles to be fluidized smoothly was clarified as 47.1μm,which corresponded to the border between Geldart-B and-A groups.Since the gangue and coal components in the raw coal were crushed into the same size,d_(pRm)depended on the greater one between d_(pGm)(minimum size required for the gangue particles to sink towards the bottom)and d_(pCm)(minimum size required for the coal particles to float towards the top).dpcm was determined as 259μm by supposing that provided the gangue particles accumulated in the lower half bed,they could be potentially extracted from the bottom.On the other hand,it was observed that the coal particles could always accumulate in the upper half bed.Under such circumstances,dpcm was revealed as 9.8μm since finer coal particles would be blown out by air before the 47.1μm sized magnetite particles became fluidized.Eventually,dpRm was clarified as 259μm,agreeing with the common view that raw coal coarser than 6 mm could be effectively beneficiated in the air-fluidized bed with magnetite particles.Additionally,the difficulty in beneficiating the fine raw coal was revealed to arise more from the remixing of sorted gangue particles than that of separated coal particles.展开更多
High-steep waste dumps in open-pit mines frequently demonstrate complex particle-size distributions and fractal characteristics along their slopes,which have a significant impact on slope stability.This study takes th...High-steep waste dumps in open-pit mines frequently demonstrate complex particle-size distributions and fractal characteristics along their slopes,which have a significant impact on slope stability.This study takes the Dasuji South waste dump in Inner Mongolia as a case to quantify the fractal dimensions of soil-rock mixtures at various slope heights,and to clarify how these fractal properties govern shear strength and deformation behavior under overlying stress,thereby affecting the overall stability of the waste dump slope.Field sampling and laboratory tests were conducted to determine the particle-size composition and fractal dimensions while direct shear tests were conducted and revealed that lower fractal dimensions indicating coarser particle assemblages significantly enhance shear resistance.Complementary PFC_(2)D discrete element simulations demonstrate that slopes composed of lower-fractaldimension materials deform less and contain localized deformation zones,whereas higher-fractal-dimension slopes experience more extensive displacement and a heightened risk of landslides.These findings refine our understanding of the relationship between fractal grain-size distribution and slope stability,providing a robust theoretical basis for improved stability assessment and optimized support strategies in deep open-pit mining waste dumps,and ultimately aiding in more effective disaster prevention within geotechnical engineering.展开更多
In this study,an artificial intelligence-based machine vision system was developed for in-line particle size analysis during the pellet layering process.Drug-layered pellets were produced by coating microcrystalline c...In this study,an artificial intelligence-based machine vision system was developed for in-line particle size analysis during the pellet layering process.Drug-layered pellets were produced by coating microcrystalline cellulose cores with an ibuprofen-containing layering liquid until the target drug content was achieved.Drug content increases with pellet size;therefore,particle size monitoring can ensure product safety and quality.The direct imaging system,consisting of a rigid endoscope,a light source,and a high-speed camera,provides real-time information about pellet size and layer uniformity,enabling timely intervention in the case of out-of-spec products.A convolutional neural network-based instance segmentation algorithm was employed to detect particles in focus,ensuring that pellet size could be accurately determined despite the dense flow of the particles.After training the model,the performance of the developed system was assessed by analysing the particle size distribution of pellet cores with variable sizes within the 250 e850 mm size range.The endoscopic system was tested in-line at a larger scale during the drug layering of inert pellet cores.The particle size data acquired in real time with the endoscopic imaging system corresponded with the reference methods,demonstrating the feasibility of the proposed machine vision-based method as a process analytical technology tool for in-line process monitoring.展开更多
Multi-label feature selection(MFS)is a crucial dimensionality reduction technique aimed at identifying informative features associated with multiple labels.However,traditional centralized methods face significant chal...Multi-label feature selection(MFS)is a crucial dimensionality reduction technique aimed at identifying informative features associated with multiple labels.However,traditional centralized methods face significant challenges in privacy-sensitive and distributed settings,often neglecting label dependencies and suffering from low computational efficiency.To address these issues,we introduce a novel framework,Fed-MFSDHBCPSO—federated MFS via dual-layer hybrid breeding cooperative particle swarm optimization algorithm with manifold and sparsity regularization(DHBCPSO-MSR).Leveraging the federated learning paradigm,Fed-MFSDHBCPSO allows clients to perform local feature selection(FS)using DHBCPSO-MSR.Locally selected feature subsets are encrypted with differential privacy(DP)and transmitted to a central server,where they are securely aggregated and refined through secure multi-party computation(SMPC)until global convergence is achieved.Within each client,DHBCPSO-MSR employs a dual-layer FS strategy.The inner layer constructs sample and label similarity graphs,generates Laplacian matrices to capture the manifold structure between samples and labels,and applies L2,1-norm regularization to sparsify the feature subset,yielding an optimized feature weight matrix.The outer layer uses a hybrid breeding cooperative particle swarm optimization algorithm to further refine the feature weight matrix and identify the optimal feature subset.The updated weight matrix is then fed back to the inner layer for further optimization.Comprehensive experiments on multiple real-world multi-label datasets demonstrate that Fed-MFSDHBCPSO consistently outperforms both centralized and federated baseline methods across several key evaluation metrics.展开更多
To clarify the effect of SnO2 particle size on the arc erosion behavior of AgSnO2 contact material, Ag?4%SnO2 (mass fraction) contact materials with different sizes of SnO2 particles were fabricated by powder metallur...To clarify the effect of SnO2 particle size on the arc erosion behavior of AgSnO2 contact material, Ag?4%SnO2 (mass fraction) contact materials with different sizes of SnO2 particles were fabricated by powder metallurgy. The microstructure of Ag?4%SnO2 contact materials was characterized, and the relative density, hardness and electrical conductivity were measured. The arc erosion of Ag?4%SnO2 contact materials was tested, the arc duration and mass loss before and after arc erosion were determined, the surface morphologies and compositions of Ag?4%SnO2 contact materials after arc erosion were characterized, and the arc erosion mechanism of AgSnO2 contact materials was discussed. The results show that fine SnO2 particle is beneficial for the improvement of the relative density and hardness, but decreases the electrical conductivity. With the decrease of SnO2 particle size, Ag?4%SnO2contact material presents shorter arc duration, less mass loss, larger erosion area and shallower arc erosion pits.展开更多
Effects of size distribution (particle size and content of fine fraction (<10μm)) on scheelite flotation were studied using flotation tests and theoretical calculations. The results show that particle size influen...Effects of size distribution (particle size and content of fine fraction (<10μm)) on scheelite flotation were studied using flotation tests and theoretical calculations. The results show that particle size influences the scheelite recovery and the performance of combined reagents. The scheelite recovery is lowered by adding fine particles (<10μm) into the pulp containing coarse particles. Extended DLVO (EDLVO) theory confirms that the fine fractions (<10μm) could interface with the coarse fractions. The interaction energy and fluid forces are relative to the particle size, which might explain why the fine fractions influence the scheelite flotation. The highest recovery of scheelite using combined reagents as collector and optimum ratio of combined reagents were determined by scheelite particle size and reagent performance. However, the optimum adding order was only determined by reagent performance, which has nothing to do with particle size.展开更多
Al2O3p-Al composites were synthesized using an in-situ reaction in the 80%Al-20%CuO （mass fraction） system. The effects of the CuO particle size on the synthesis temperature and microstructure of the composites were...Al2O3p-Al composites were synthesized using an in-situ reaction in the 80%Al-20%CuO （mass fraction） system. The effects of the CuO particle size on the synthesis temperature and microstructure of the composites were investigated by various methods. The results indicate that the CuO particle size has a significant effect on the temperature at which the complete reaction in the Al-CuO system occurs：the temperature is 200 ℃ lower in the Al-CuO system containing CuO particles with sizes less than 6μm than that containing CuO particles with sizes less than 100μm. The interfacial bonding between Al2O3 particles and Al is not complete when the temperature is below a critical value. The morphology of the Al2O3 particles varies from ribbon-like shape to near spherical shape when the temperature is above a critical value. These two critical temperatures are affected by the particle size of CuO, and the critical temperature of the sample containing CuO particles with sizes less than 6μm is 100 ℃ lower than that of the sample containing CuO particles with sizes less than 100μm.展开更多
Application of particle image velocity (PIV) techniques for measuringparticle size distribution and total number in an activation chamber of desulfurization system isintroduced. Watersheld algorithm is used to choose ...Application of particle image velocity (PIV) techniques for measuringparticle size distribution and total number in an activation chamber of desulfurization system isintroduced. Watersheld algorithm is used to choose the suitable initial gray level threshold whichis used to change the gray level images taken by PIV to black and white ones, then every particle inan image is isolated totally. For every isolating particle, its contour is tracked by the edgeenhancement filter function and kept by Freeman s chain code. Based on a set of particle s chincode, its size and size distribution are calculated and sorted. Finally, the experimental data ofcalcium particles and water drops, separately injected into the activation chamber, and the erroranalysis of data are given out.展开更多
This paper presents a method of measuring the particle mean size and dust concentration by small angle near forward light scattering optics and the extinction theory. Its theory is based on Fraunhofer diffraction the...This paper presents a method of measuring the particle mean size and dust concentration by small angle near forward light scattering optics and the extinction theory. Its theory is based on Fraunhofer diffraction theory which is the approximation of Mie scattering within the forward Fraunhofer diffraction lobe, and Rosin Rammler function is introduced to describe the particle size distribution in two phase flow in advance. Compared with the values by the sample weight method, the measurement results have a reasonable agreement. The present work has demonstrated that this method will be probably used to monitor the parameters of two phase flow.展开更多
Four batch experiments of hydrolysis and acidification were carried out to investigate the distributions of proteins （PN） and polysaccharides （PS） in the sludge, the PN/PS ratio, the particle sizes, and their rela...Four batch experiments of hydrolysis and acidification were carried out to investigate the distributions of proteins （PN） and polysaccharides （PS） in the sludge, the PN/PS ratio, the particle sizes, and their relationship with sludge dewaterability （as determined by capillary suction time, CST）. The sludge flocs were stratified through centrifugation- and ultrasound-based method into four fractions： （1） slime, （2） loosely bound extracellular polymeric substances （LB-EPS）, （3） tightly bound EPS （TB-EPS）, and （4） pellet. The results showed that PN was mainly partitioned in the pellet （80.7%） and TB-EPS （9.6%） fractions, while PS distributed evenly in the four fractions. During hydrolysis and acidification, PN was transferred from the pellet and TB-EPS fractions to the slime fraction, but PS had no significant transfer trends. The mean particle sizes of the sludge flocs decreased with hydrolysis and acidification. The pH had a more significant influence on the dewaterability of sludge flocs than temperature. Sludge dewaterability during hydrolysis and acidification processes greatly deteriorated from 9.7 s at raw sludge to 340-450 s under alkaline conditions. However, it was just slightly increased under acidic conditions. Further investigation suggested that CST was affected by soluble PN, soluble PN/PS, and particle sizes of sludge flocs, but was affected slightly by total PN, PS, or PN/PS in the whole sludge flocs and other fractions （except slime）.展开更多
In order to evaluate the influence of particle size and particle concentration on the coagulation process, two kinds of particle suspensions, nanoparticles and microparticles,were employed to investigate the effect of...In order to evaluate the influence of particle size and particle concentration on the coagulation process, two kinds of particle suspensions, nanoparticles and microparticles,were employed to investigate the effect of particle size on coagulation mechanisms with varying coagulation parameters. Results showed that it is easier for nanoparticles to cause self-aggregation because of Brownian motion, while interception and sedimentation are the mainly physical processes affecting particle transport for microparticles, so they are more stable and disperse more easily. The particle size distribution and particle concentration had distinct influence on the coagulation mechanisms. Under neutral conditions, as the amount of coagulant increased, the coagulation mechanism for nanoparticles changed from charge neutralization to sweep flocculation and the nanoparticles became destabilized, re-stabilized and again destabilized. For microparticles, although the coagulation mechanism was the same as that of nanoparticles, the increased rate of aluminum hydroxide precipitation exceeded the adsorption of incipiently formed soluble alum species, resulting in the disappearance of the re-stabilization zone. Under acidic conditions, Brownian motion dominates for nanoparticles at low particle concentrations, while sweep flocculation is predominant at high particle concentrations. As for microparticles, charge neutralization and sweep flocculation are the mechanisms for low and high particle concentrations respectively.Under alkaline condition, although the mechanisms for both nano-and microparticles are the same, the morphology of flocs and the kinetics of floc formation are different. At low particle concentrations, nanoparticles have larger growth rate and final size of flocs, while at high particle concentrations, nanoparticles have higher fractal dimension and recovery factors.展开更多
Nitrobenzene has been considered as a significant groundwater contaminant due to its wide usage in explosives, insecticides, herbicides, pharmaceuticals and dyes. Nitrobenzene is of environmental concern because of it...Nitrobenzene has been considered as a significant groundwater contaminant due to its wide usage in explosives, insecticides, herbicides, pharmaceuticals and dyes. Nitrobenzene is of environmental concern because of its toxicity. In the presence of zero-valent iron （ZVI）, reduction of the nitro group is the dominant transformation process for nitrobenzene. A series of experiments were carried out to investigate the kinetics of nitrobenzene reduction by ZVI and the effects of pH and ZVI particle size on nitrobenzene removal in groundwater. The results indicated that nitrobenzene could be reduced to aniline by ZVI; the reduction of nitrobenzene by ZVI followed a pseudo first-order kinetics; the observed nitrobenzene reduction rate constant （k obs ） was 0.0006 min^-1 and the half-life of nitrobenzene （t 1/2 ） was 115.5 min; the mass balance achieved 87.5% for nitrobenzene reduction by the 1 mm ZVI particle and the final removal efficiency was 80.98%. In addition, the pH and ZVI particle size were found to exhibit significant influences on the nitrobenzene reduction. The observed nitrobenzene reduction rate constant linearly decreased with increase pH and the data fitted on polynomial regression equation for the observed nitrobenzene reduction rate constant and ZVI particle size. Therefore, use of ZVI based permeable reactive barrier technology to remedy nitrobenzene contaminated groundwater was feasible.展开更多
The experiments on the flash pyrolysis of a lignite were carried out in a fast-entrained bed reactor as a basic study on a so-called ＇ coal topping process＇. The investigation focused on the effects of pyrolysis tem...The experiments on the flash pyrolysis of a lignite were carried out in a fast-entrained bed reactor as a basic study on a so-called ＇ coal topping process＇. The investigation focused on the effects of pyrolysis temperature and coal particle size on the product distribution and composition. The experimental results show that an increase in the pyrolysis temperature results in a higher yield of gaseous products while a larger particle size leads to a decrease of the liquid yield. An optimum temperature for the liquid yield was found to be 650℃. A certain amount of phenol groups was found in the liquid products, which may be used to produce high-valued fine chemicals. The FTIR analyses of the coal and chars show that aliphatic structures in the chars are gradually replaced by aromatic structures with the increasing of pyrolysis temperature and coal particle size. The results of this study provide fundamental data and optimal conditions to maximize light oils yields for the coal topping process.展开更多
Spark plasma sintering （SPS） was used to fabricate Al/diamond composites. The influence of diamond particle size on the microstructure and thermal conductivity （TC） of composites was investigated by combining expe...Spark plasma sintering （SPS） was used to fabricate Al/diamond composites. The influence of diamond particle size on the microstructure and thermal conductivity （TC） of composites was investigated by combining experimental results with model prediction. The results show that both composites with 40 pan particles and 70 μm particles exhibit high density and good TC, and the composite with 70 μm particles indicates an excellent TC of 325 W.m^-1.K^-1. Their TCs lay between the theoretical estimated bounds. In contrast, the composite with 100 lain particles demonstrates low density as well as poor TC due to its high porosity and weak interfacial bonding. Its TC is even considerably less than the lower bound of the predicted value. Using larger diamond particles can further enhance thermal conductive performance only based on the premise that highly dense composites of strong interfacial bonding can be obtained.展开更多
New particle formation is a key process in shaping the size distribution of aerosols in the atmosphere.We present here the measurement results of number and size distribution of aerosol particles （10–10000 nm in dia...New particle formation is a key process in shaping the size distribution of aerosols in the atmosphere.We present here the measurement results of number and size distribution of aerosol particles （10–10000 nm in diameter） obtained in the summer of 2008,at a suburban site in Beijing,China.We firstly reported the pollution level,particle number size distribution,diurnal variation of the particle number size distribution and then introduced the characteristics of the particle formation processes.The results showed that the number concentration of ultrafine particles was much lower than the values measured in other urban or suburban areas in previous studies.Sharp increases of ultrafine particle count were frequently observed at noon.An examination of the diurnal pattern suggested that the burst of ultrafine particles was mainly due to new particle formation promoted by photochemical processes.In addition,high relative humidity was a key factor driving the growth of the particles in the afternoon.During the 2-month observations,new particle formation from homogeneous nucleation was observed for 42.7% of the study period.The average growth rate of newly formed particles was 3.2 nm/hr,and varied from 1.2 to 8.0 nm/hr.The required concentration of condensable vapor was 4.4×10 7 cm-3,and its source rate was 1.2×10 6 cm-3 sec-1.Further calculation on the source rate of sulphuric acid vapor indicated that the average participation of sulphuric acid to particle growth rates was 28.7%.展开更多
Background: In rumen fermentation, fumaric acid(FA) could competitively utilize hydrogen with methanogenesis to enhance propionate production and suppress methane emission, but both effects were diet-dependent. This s...Background: In rumen fermentation, fumaric acid(FA) could competitively utilize hydrogen with methanogenesis to enhance propionate production and suppress methane emission, but both effects were diet-dependent. This study aimed to explore the effects of FA supplementation on methanogenesis and rumen fermentation in goats fed diets varying in forage and concentrate particle size.Methods: Four rumen-cannulated goats were used in a 4 × 4 Latin square design with a 2 × 2 factorial arrangement of treatments: low or high ratio of forage particle size: concentrate particle size(Fps:Cps), without or with FA supplementation(24 g/d). Fps:Cps was higher in the diet with chopped alfalfa hay plus ground corn than in that with ground alfalfa hay plus crushed corn.Results: Both increasing dietary Fps:Cps and FA supplementation shifted ruminal volatile fatty acid(VFA) patterns toward more propionate and less acetate in goats. An interaction between dietary Fps:Cps and FA supplementation was observed for the ratio of acetate to propionate(A:P), which was more predominant when FA was supplemented in the low-Fps:Cps diet. Methane production was reduced by FA, and the reduction was larger in the low-Fps:Cps diet(31.72%) than in the high-Fps:Cps diet(17.91%). Fumaric acid decreased ruminal total VFA concentration and increased ruminal p H. No difference was found in ruminal DM degradation of concentrate or alfalfa hay by dietary Fps:Cps or FA. Goats presented a lower ruminal methanogen abundance with FA supplementation and a higher B. fibrisolvens abundance with high dietary Fps:Cps.Conclusions: Adjusting dietary Fps:Cps is an alternative dietary model for studying diet-dependent effects without changing dietary chemical composition. Fumaric acid supplementation in the low-Fps:Cps diet showed greater responses in methane mitigation and propionate increase.展开更多
The toughness of ferritic steels is influenced by the grain size distribution, second phase, precipitates and coarse inclusions. In this work an examination of the effect of coarse TiN particles （〉0.5 μm） and ferr...The toughness of ferritic steels is influenced by the grain size distribution, second phase, precipitates and coarse inclusions. In this work an examination of the effect of coarse TiN particles （〉0.5 μm） and ferrite grain size on the Charpy impact transition temperature in high strength low alloyed steels has been carried out. Steels with high Ti content （up to 0.045 wt%）, have been heat-treated and furnace cooled to obtain a ferrite-pearlite microstructure with different ferrite grain sizes. Coarse TiN particle size and ferrite grain size distributions have been measured and Charpy impact testing has been carried out. Scanning electron microscopy （SEM） analysis has been used to measure the grain boundary carbide thickness and to determine if the coarse TiN particles are acting as cleavage initiation sites by fractographic analysis. The Charpy ductile-brittle transition temperatures （DBTT） have been predicted using standard literature equations, and compared to the measured values. The relationship between the ferrite grain size and coarse TiN particle size and number density in terms of whether the coarse TiN particles act as effective cleavage initiation sites is discussed in this paper.展开更多
基金"PSPC Régions n°2"("Projets Structurants des Pôles de Compétitivitéen région")funded by Conseil Régional Hauts-de-France and BPI.
文摘Developing the railway transport sector is a challenging scientific,economic and social research topic starting with ensuring human security.The main topic that should be developed in that sense is the ballast stability and dynamical behaviour under external loading and environmental changes.This paper investigates the effect of particle size distribution and normal pressure on the mechanical response of a ballast bed.Grading curves of ballast layers with different sizes are illustrated to discuss their strength behaviour under various strains to deduce the significant effect on the direct shear performance of the ballast layer.Direct shear tests with different Particle Size Distribution(PSD)were reproduced using the Discrete Element Method(DEM).It is noticed that when the number of small-sized ballast increases,the shear strength and the friction angle increase to varying degrees under different normal pressures,with an average increase of 27%and 8%,respectively.When the number of large-sized ballast decreases,the shear strength and the friction angle decrease to varying degrees under different normal pressures,with an average decrease of 6%and 3%,respectively.
基金supported by the Equipment Pre-research and Sharing Technology(41423030503)provided funding for this workThe Equipment Pre-research and Sharing Technology(41423030503)funded this work.
文摘This work used 5CrMnMo steel and titanium carbide(TiC)powders to fabricate particulate metal matrix composites(PMMCS).The composites’microstructure,hardness,and impact toughness were compared with four different titanium carbide ceramic particle sizes.The phase composition and microstructure of composites were studied.Vickers hardness and Charpy impact tests were employed to analyze composites’hardness and impact ductility,respectively.The results showed that the four groups of composites are mainly composed of martensite,trace residual austenite,and titanium carbide(undissolved TiC and primary TiC particles).With the growth of the ceramic particle dimension in the composite layer,the number of primary titanium carbide ceramics gradually decreased.When the initial ceramic particle size was small,it tended to generate dendritic primary TiC,and when the particle size was large,it tended to generate polygons and ellipsoids.Furthermore,with the growth of titanium carbide ceramic particle dimension in the composites,the hardness of the composites decreased but the impact toughness of the composites rose first and then descended.When the ceramic particle size was 50-75μm,the composite had the highest hardness,and the impact energy of the composites was the highest,which is 8 J.This was because there were more undissolved titanium carbide ceramics in the composite,and there was a thicker matrix metal between the ceramic particles.
基金support of the National Key Research and Development Program of China(2023YFD2100403)the Agricultural Science and Technology Innovation Program of Chinese Academy of Agricultural Sciences(CAAS-ASTIP-2021-OCRI)+3 种基金the Earmarked Fund for CARS-14the Innovation Group Project of Hubei Province(2023AFA042)the Key Research Projects of Hubei Province(2020BBA045)the Knowledge Innovation Program of Wuhan-Basic Research(3562).
文摘The increased risk of chronic diseases has led to increasing importance of coarse foods in daily life,but the inclusion of new ingredients has a great degree of influence on the structural characteristics and sensory qualities of the food.The effects of five different particle size variations on the physicochemical characteristics,dough,and steamed bread structure of Flaxseed-based milk coproduct(FMC)were investigated.As the particle size decreases,the structure of the dough becomes denser due to an increase in water retention capacity and dissolution capacity,weakening the competition for dough moisture and allowing for an increase in air-holding capacity.The reduction in particle size increased the specific volume of the steamed bread,a decrease in the spread ratio,and an optimization of hardness and elasticity,as well as an increase in consumer acceptance of the FMC steamed bread.However,it is not the smaller the particle size,the higher the quality of steamed bread,appropriate reduction of particle size can improve the quality of steamed bread.In addition,the addition of FMC reduces fat digestion.Therefore,the present study proposes a method to change the particle size of FMC to optimize the quality of the steamed bread and to reduce fat digestibility by adding FMC.
基金supported by Shandong Provincial Natural Science Foundation(ZR2023MB038)Youth Innovation Team Program of Shandong Higher Education Institution(2022KJ156)。
文摘A feasible criterion was established to determine the lower size limit of raw coal(d_(pRm))for efficient beneficiation in the air-fluidized bed with magnetite particles.The feasibility of using small magnetite particles to accommodate the fine raw coal was demonstrated from the experimental perspective.The minimum size for the magnetite particles to be fluidized smoothly was clarified as 47.1μm,which corresponded to the border between Geldart-B and-A groups.Since the gangue and coal components in the raw coal were crushed into the same size,d_(pRm)depended on the greater one between d_(pGm)(minimum size required for the gangue particles to sink towards the bottom)and d_(pCm)(minimum size required for the coal particles to float towards the top).dpcm was determined as 259μm by supposing that provided the gangue particles accumulated in the lower half bed,they could be potentially extracted from the bottom.On the other hand,it was observed that the coal particles could always accumulate in the upper half bed.Under such circumstances,dpcm was revealed as 9.8μm since finer coal particles would be blown out by air before the 47.1μm sized magnetite particles became fluidized.Eventually,dpRm was clarified as 259μm,agreeing with the common view that raw coal coarser than 6 mm could be effectively beneficiated in the air-fluidized bed with magnetite particles.Additionally,the difficulty in beneficiating the fine raw coal was revealed to arise more from the remixing of sorted gangue particles than that of separated coal particles.
基金supported by the National Key Research and Development Program of China(2024YFC2909500)State Key Laboratory of Intelligent Construction and Healthy Operation and Maintenance of Deep Underground Engineering(SDGZ2505)National Natural Science Foundation of China(42377148)。
文摘High-steep waste dumps in open-pit mines frequently demonstrate complex particle-size distributions and fractal characteristics along their slopes,which have a significant impact on slope stability.This study takes the Dasuji South waste dump in Inner Mongolia as a case to quantify the fractal dimensions of soil-rock mixtures at various slope heights,and to clarify how these fractal properties govern shear strength and deformation behavior under overlying stress,thereby affecting the overall stability of the waste dump slope.Field sampling and laboratory tests were conducted to determine the particle-size composition and fractal dimensions while direct shear tests were conducted and revealed that lower fractal dimensions indicating coarser particle assemblages significantly enhance shear resistance.Complementary PFC_(2)D discrete element simulations demonstrate that slopes composed of lower-fractaldimension materials deform less and contain localized deformation zones,whereas higher-fractal-dimension slopes experience more extensive displacement and a heightened risk of landslides.These findings refine our understanding of the relationship between fractal grain-size distribution and slope stability,providing a robust theoretical basis for improved stability assessment and optimized support strategies in deep open-pit mining waste dumps,and ultimately aiding in more effective disaster prevention within geotechnical engineering.
基金Project no.RRF-2.3.1-21-2022-00015 has been implemented with the support provided by the European Unionsupported by the Agency for Credits and Study Grants coordinated by the Romanian Ministry of National Education from the source of the research grant established through the Government Decision no.118/2023+1 种基金supported by the EKÖP-24-3-BME-103 New National Excellence Program of the Ministry for Culture and Innovation from the source of the National,Research,Development and Innovation Fundsupported by the Doctoral Excellence Fellowship Programme(DCEP)is funded by the National Research Development and Innovation Fund of the Ministry of Culture and Innovation and the Budapest University of Technology and Economics,under a grant agreement with the National Research,Development and Innovation Office.
文摘In this study,an artificial intelligence-based machine vision system was developed for in-line particle size analysis during the pellet layering process.Drug-layered pellets were produced by coating microcrystalline cellulose cores with an ibuprofen-containing layering liquid until the target drug content was achieved.Drug content increases with pellet size;therefore,particle size monitoring can ensure product safety and quality.The direct imaging system,consisting of a rigid endoscope,a light source,and a high-speed camera,provides real-time information about pellet size and layer uniformity,enabling timely intervention in the case of out-of-spec products.A convolutional neural network-based instance segmentation algorithm was employed to detect particles in focus,ensuring that pellet size could be accurately determined despite the dense flow of the particles.After training the model,the performance of the developed system was assessed by analysing the particle size distribution of pellet cores with variable sizes within the 250 e850 mm size range.The endoscopic system was tested in-line at a larger scale during the drug layering of inert pellet cores.The particle size data acquired in real time with the endoscopic imaging system corresponded with the reference methods,demonstrating the feasibility of the proposed machine vision-based method as a process analytical technology tool for in-line process monitoring.
文摘Multi-label feature selection(MFS)is a crucial dimensionality reduction technique aimed at identifying informative features associated with multiple labels.However,traditional centralized methods face significant challenges in privacy-sensitive and distributed settings,often neglecting label dependencies and suffering from low computational efficiency.To address these issues,we introduce a novel framework,Fed-MFSDHBCPSO—federated MFS via dual-layer hybrid breeding cooperative particle swarm optimization algorithm with manifold and sparsity regularization(DHBCPSO-MSR).Leveraging the federated learning paradigm,Fed-MFSDHBCPSO allows clients to perform local feature selection(FS)using DHBCPSO-MSR.Locally selected feature subsets are encrypted with differential privacy(DP)and transmitted to a central server,where they are securely aggregated and refined through secure multi-party computation(SMPC)until global convergence is achieved.Within each client,DHBCPSO-MSR employs a dual-layer FS strategy.The inner layer constructs sample and label similarity graphs,generates Laplacian matrices to capture the manifold structure between samples and labels,and applies L2,1-norm regularization to sparsify the feature subset,yielding an optimized feature weight matrix.The outer layer uses a hybrid breeding cooperative particle swarm optimization algorithm to further refine the feature weight matrix and identify the optimal feature subset.The updated weight matrix is then fed back to the inner layer for further optimization.Comprehensive experiments on multiple real-world multi-label datasets demonstrate that Fed-MFSDHBCPSO consistently outperforms both centralized and federated baseline methods across several key evaluation metrics.
基金Project(51274163)supported by the National Natural Science Foundation of ChinaProject(13JS076)supported by the Key Laboratory Research Program of Shaanxi Province,China+1 种基金Project(2012KCT-25)supported by the Pivot Innovation Team of Shaanxi Electrical Materials and Infiltration Technique,ChinaProject(2011HBSZS009)supported by the Special Foundation of Key Disciplines,China
文摘To clarify the effect of SnO2 particle size on the arc erosion behavior of AgSnO2 contact material, Ag?4%SnO2 (mass fraction) contact materials with different sizes of SnO2 particles were fabricated by powder metallurgy. The microstructure of Ag?4%SnO2 contact materials was characterized, and the relative density, hardness and electrical conductivity were measured. The arc erosion of Ag?4%SnO2 contact materials was tested, the arc duration and mass loss before and after arc erosion were determined, the surface morphologies and compositions of Ag?4%SnO2 contact materials after arc erosion were characterized, and the arc erosion mechanism of AgSnO2 contact materials was discussed. The results show that fine SnO2 particle is beneficial for the improvement of the relative density and hardness, but decreases the electrical conductivity. With the decrease of SnO2 particle size, Ag?4%SnO2contact material presents shorter arc duration, less mass loss, larger erosion area and shallower arc erosion pits.
基金Project(51074037)supported by the National Natural Science Foundation of China
文摘Effects of size distribution (particle size and content of fine fraction (<10μm)) on scheelite flotation were studied using flotation tests and theoretical calculations. The results show that particle size influences the scheelite recovery and the performance of combined reagents. The scheelite recovery is lowered by adding fine particles (<10μm) into the pulp containing coarse particles. Extended DLVO (EDLVO) theory confirms that the fine fractions (<10μm) could interface with the coarse fractions. The interaction energy and fluid forces are relative to the particle size, which might explain why the fine fractions influence the scheelite flotation. The highest recovery of scheelite using combined reagents as collector and optimum ratio of combined reagents were determined by scheelite particle size and reagent performance. However, the optimum adding order was only determined by reagent performance, which has nothing to do with particle size.
基金Project(2012MS0801)supported by the Natural Science Foundation of Inner Mongolia,China
文摘Al2O3p-Al composites were synthesized using an in-situ reaction in the 80%Al-20%CuO （mass fraction） system. The effects of the CuO particle size on the synthesis temperature and microstructure of the composites were investigated by various methods. The results indicate that the CuO particle size has a significant effect on the temperature at which the complete reaction in the Al-CuO system occurs：the temperature is 200 ℃ lower in the Al-CuO system containing CuO particles with sizes less than 6μm than that containing CuO particles with sizes less than 100μm. The interfacial bonding between Al2O3 particles and Al is not complete when the temperature is below a critical value. The morphology of the Al2O3 particles varies from ribbon-like shape to near spherical shape when the temperature is above a critical value. These two critical temperatures are affected by the particle size of CuO, and the critical temperature of the sample containing CuO particles with sizes less than 6μm is 100 ℃ lower than that of the sample containing CuO particles with sizes less than 100μm.
基金The Special Funds for State Key Projects for Fun- damental Research (G1999022201-04).
文摘Application of particle image velocity (PIV) techniques for measuringparticle size distribution and total number in an activation chamber of desulfurization system isintroduced. Watersheld algorithm is used to choose the suitable initial gray level threshold whichis used to change the gray level images taken by PIV to black and white ones, then every particle inan image is isolated totally. For every isolating particle, its contour is tracked by the edgeenhancement filter function and kept by Freeman s chain code. Based on a set of particle s chincode, its size and size distribution are calculated and sorted. Finally, the experimental data ofcalcium particles and water drops, separately injected into the activation chamber, and the erroranalysis of data are given out.
文摘This paper presents a method of measuring the particle mean size and dust concentration by small angle near forward light scattering optics and the extinction theory. Its theory is based on Fraunhofer diffraction theory which is the approximation of Mie scattering within the forward Fraunhofer diffraction lobe, and Rosin Rammler function is introduced to describe the particle size distribution in two phase flow in advance. Compared with the values by the sample weight method, the measurement results have a reasonable agreement. The present work has demonstrated that this method will be probably used to monitor the parameters of two phase flow.
基金supported by the National Hi-Tech Research and Development Program (863) of China (No. 2006AA06Z384).
文摘Four batch experiments of hydrolysis and acidification were carried out to investigate the distributions of proteins （PN） and polysaccharides （PS） in the sludge, the PN/PS ratio, the particle sizes, and their relationship with sludge dewaterability （as determined by capillary suction time, CST）. The sludge flocs were stratified through centrifugation- and ultrasound-based method into four fractions： （1） slime, （2） loosely bound extracellular polymeric substances （LB-EPS）, （3） tightly bound EPS （TB-EPS）, and （4） pellet. The results showed that PN was mainly partitioned in the pellet （80.7%） and TB-EPS （9.6%） fractions, while PS distributed evenly in the four fractions. During hydrolysis and acidification, PN was transferred from the pellet and TB-EPS fractions to the slime fraction, but PS had no significant transfer trends. The mean particle sizes of the sludge flocs decreased with hydrolysis and acidification. The pH had a more significant influence on the dewaterability of sludge flocs than temperature. Sludge dewaterability during hydrolysis and acidification processes greatly deteriorated from 9.7 s at raw sludge to 340-450 s under alkaline conditions. However, it was just slightly increased under acidic conditions. Further investigation suggested that CST was affected by soluble PN, soluble PN/PS, and particle sizes of sludge flocs, but was affected slightly by total PN, PS, or PN/PS in the whole sludge flocs and other fractions （except slime）.
基金supported by the National Natural Science Foundation of China(No.51808530)
文摘In order to evaluate the influence of particle size and particle concentration on the coagulation process, two kinds of particle suspensions, nanoparticles and microparticles,were employed to investigate the effect of particle size on coagulation mechanisms with varying coagulation parameters. Results showed that it is easier for nanoparticles to cause self-aggregation because of Brownian motion, while interception and sedimentation are the mainly physical processes affecting particle transport for microparticles, so they are more stable and disperse more easily. The particle size distribution and particle concentration had distinct influence on the coagulation mechanisms. Under neutral conditions, as the amount of coagulant increased, the coagulation mechanism for nanoparticles changed from charge neutralization to sweep flocculation and the nanoparticles became destabilized, re-stabilized and again destabilized. For microparticles, although the coagulation mechanism was the same as that of nanoparticles, the increased rate of aluminum hydroxide precipitation exceeded the adsorption of incipiently formed soluble alum species, resulting in the disappearance of the re-stabilization zone. Under acidic conditions, Brownian motion dominates for nanoparticles at low particle concentrations, while sweep flocculation is predominant at high particle concentrations. As for microparticles, charge neutralization and sweep flocculation are the mechanisms for low and high particle concentrations respectively.Under alkaline condition, although the mechanisms for both nano-and microparticles are the same, the morphology of flocs and the kinetics of floc formation are different. At low particle concentrations, nanoparticles have larger growth rate and final size of flocs, while at high particle concentrations, nanoparticles have higher fractal dimension and recovery factors.
基金supported by the National High Technology Research and Development Program(863) of China(No.2007AA06A410)the Water Pollution Control and Management Project(No.2008ZX07207-007-05)the National Natural Science Foundation of China(No.40802055)
文摘Nitrobenzene has been considered as a significant groundwater contaminant due to its wide usage in explosives, insecticides, herbicides, pharmaceuticals and dyes. Nitrobenzene is of environmental concern because of its toxicity. In the presence of zero-valent iron （ZVI）, reduction of the nitro group is the dominant transformation process for nitrobenzene. A series of experiments were carried out to investigate the kinetics of nitrobenzene reduction by ZVI and the effects of pH and ZVI particle size on nitrobenzene removal in groundwater. The results indicated that nitrobenzene could be reduced to aniline by ZVI; the reduction of nitrobenzene by ZVI followed a pseudo first-order kinetics; the observed nitrobenzene reduction rate constant （k obs ） was 0.0006 min^-1 and the half-life of nitrobenzene （t 1/2 ） was 115.5 min; the mass balance achieved 87.5% for nitrobenzene reduction by the 1 mm ZVI particle and the final removal efficiency was 80.98%. In addition, the pH and ZVI particle size were found to exhibit significant influences on the nitrobenzene reduction. The observed nitrobenzene reduction rate constant linearly decreased with increase pH and the data fitted on polynomial regression equation for the observed nitrobenzene reduction rate constant and ZVI particle size. Therefore, use of ZVI based permeable reactive barrier technology to remedy nitrobenzene contaminated groundwater was feasible.
文摘The experiments on the flash pyrolysis of a lignite were carried out in a fast-entrained bed reactor as a basic study on a so-called ＇ coal topping process＇. The investigation focused on the effects of pyrolysis temperature and coal particle size on the product distribution and composition. The experimental results show that an increase in the pyrolysis temperature results in a higher yield of gaseous products while a larger particle size leads to a decrease of the liquid yield. An optimum temperature for the liquid yield was found to be 650℃. A certain amount of phenol groups was found in the liquid products, which may be used to produce high-valued fine chemicals. The FTIR analyses of the coal and chars show that aliphatic structures in the chars are gradually replaced by aromatic structures with the increasing of pyrolysis temperature and coal particle size. The results of this study provide fundamental data and optimal conditions to maximize light oils yields for the coal topping process.
基金supported by the National Natural Science Foundation of China (No.50971020)the National High-Tech Research and Development Program of China (No.2008AA03Z505)
文摘Spark plasma sintering （SPS） was used to fabricate Al/diamond composites. The influence of diamond particle size on the microstructure and thermal conductivity （TC） of composites was investigated by combining experimental results with model prediction. The results show that both composites with 40 pan particles and 70 μm particles exhibit high density and good TC, and the composite with 70 μm particles indicates an excellent TC of 325 W.m^-1.K^-1. Their TCs lay between the theoretical estimated bounds. In contrast, the composite with 100 lain particles demonstrates low density as well as poor TC due to its high porosity and weak interfacial bonding. Its TC is even considerably less than the lower bound of the predicted value. Using larger diamond particles can further enhance thermal conductive performance only based on the premise that highly dense composites of strong interfacial bonding can be obtained.
基金supported by the National Department Public Benefit Research Foundation of China (No.201009001)the National Natural Science Foundation of China (No.41005065)the Basic Foundation for Public Benefit-Research Academies from the Central Government (No.2008KYYW01)
文摘New particle formation is a key process in shaping the size distribution of aerosols in the atmosphere.We present here the measurement results of number and size distribution of aerosol particles （10–10000 nm in diameter） obtained in the summer of 2008,at a suburban site in Beijing,China.We firstly reported the pollution level,particle number size distribution,diurnal variation of the particle number size distribution and then introduced the characteristics of the particle formation processes.The results showed that the number concentration of ultrafine particles was much lower than the values measured in other urban or suburban areas in previous studies.Sharp increases of ultrafine particle count were frequently observed at noon.An examination of the diurnal pattern suggested that the burst of ultrafine particles was mainly due to new particle formation promoted by photochemical processes.In addition,high relative humidity was a key factor driving the growth of the particles in the afternoon.During the 2-month observations,new particle formation from homogeneous nucleation was observed for 42.7% of the study period.The average growth rate of newly formed particles was 3.2 nm/hr,and varied from 1.2 to 8.0 nm/hr.The required concentration of condensable vapor was 4.4×10 7 cm-3,and its source rate was 1.2×10 6 cm-3 sec-1.Further calculation on the source rate of sulphuric acid vapor indicated that the average participation of sulphuric acid to particle growth rates was 28.7%.
基金supported by the National Key Research and Development Program of China(2017YFD0500500)Key Research and Development Program of Shaanxi Province(2017ZDXM-NY-086)
文摘Background: In rumen fermentation, fumaric acid(FA) could competitively utilize hydrogen with methanogenesis to enhance propionate production and suppress methane emission, but both effects were diet-dependent. This study aimed to explore the effects of FA supplementation on methanogenesis and rumen fermentation in goats fed diets varying in forage and concentrate particle size.Methods: Four rumen-cannulated goats were used in a 4 × 4 Latin square design with a 2 × 2 factorial arrangement of treatments: low or high ratio of forage particle size: concentrate particle size(Fps:Cps), without or with FA supplementation(24 g/d). Fps:Cps was higher in the diet with chopped alfalfa hay plus ground corn than in that with ground alfalfa hay plus crushed corn.Results: Both increasing dietary Fps:Cps and FA supplementation shifted ruminal volatile fatty acid(VFA) patterns toward more propionate and less acetate in goats. An interaction between dietary Fps:Cps and FA supplementation was observed for the ratio of acetate to propionate(A:P), which was more predominant when FA was supplemented in the low-Fps:Cps diet. Methane production was reduced by FA, and the reduction was larger in the low-Fps:Cps diet(31.72%) than in the high-Fps:Cps diet(17.91%). Fumaric acid decreased ruminal total VFA concentration and increased ruminal p H. No difference was found in ruminal DM degradation of concentrate or alfalfa hay by dietary Fps:Cps or FA. Goats presented a lower ruminal methanogen abundance with FA supplementation and a higher B. fibrisolvens abundance with high dietary Fps:Cps.Conclusions: Adjusting dietary Fps:Cps is an alternative dietary model for studying diet-dependent effects without changing dietary chemical composition. Fumaric acid supplementation in the low-Fps:Cps diet showed greater responses in methane mitigation and propionate increase.
文摘The toughness of ferritic steels is influenced by the grain size distribution, second phase, precipitates and coarse inclusions. In this work an examination of the effect of coarse TiN particles （〉0.5 μm） and ferrite grain size on the Charpy impact transition temperature in high strength low alloyed steels has been carried out. Steels with high Ti content （up to 0.045 wt%）, have been heat-treated and furnace cooled to obtain a ferrite-pearlite microstructure with different ferrite grain sizes. Coarse TiN particle size and ferrite grain size distributions have been measured and Charpy impact testing has been carried out. Scanning electron microscopy （SEM） analysis has been used to measure the grain boundary carbide thickness and to determine if the coarse TiN particles are acting as cleavage initiation sites by fractographic analysis. The Charpy ductile-brittle transition temperatures （DBTT） have been predicted using standard literature equations, and compared to the measured values. The relationship between the ferrite grain size and coarse TiN particle size and number density in terms of whether the coarse TiN particles act as effective cleavage initiation sites is discussed in this paper.
