Based on various ultrasonic loss mechanisms, the formula of the cumulative mass percentage of minerals with different particle sizes was given, with which the particle size distribution was integrated into an ultrason...Based on various ultrasonic loss mechanisms, the formula of the cumulative mass percentage of minerals with different particle sizes was given, with which the particle size distribution was integrated into an ultrasonic attenuation model. And then the correlations between the ultrasonic attenuation and the pulp density, and the particle size were obtained. The derived model was combined with the experiment and the analysis of experimental data to determine the inverse model relating ultrasonic attenuation coefficient with size distribution. Finally, an optimization method of inverse parameter, genetic algorithm was applied for particle size distribution. The results of inverse calculation show that the precision of measurement was high.展开更多
High purity and ultrafine DAAF(u-DAAF)is an emerging insensitive charge in initiators.Although there are many ways to obtain u-DAAF,developing a preparation method with stable operation,accurate control,good quality c...High purity and ultrafine DAAF(u-DAAF)is an emerging insensitive charge in initiators.Although there are many ways to obtain u-DAAF,developing a preparation method with stable operation,accurate control,good quality consistency,equipment miniaturization,and minimum manpower is an inevitable requirement to adapt to the current social technology development trend.Here reported is the microfluidic preparation of u-DAAF with tunable particle size by a passive swirling microreactor.Under the guidance of recrystallization growth kinetics and mixing behavior of fluids in the swirling microreactor,the key parameters(liquid flow rate,explosive concentration and crystallization temperature)were screened and optimized through screening experiments.Under the condition that no surfactant is added and only experimental parameters are controlled,the particle size of recrystallized DAAF can be adjusted from 98 nm to 785 nm,and the corresponding specific surface area is 8.45 m^(2)·g^(-1)to 1.33 m^(2)·g^(-1).In addition,the preparation method has good batch stability,high yield(90.8%-92.6%)and high purity(99.0%-99.4%),indicating a high practical application potential.Electric explosion derived flyer initiation tests demonstrate that the u-DAAF shows an initiation sensitivity much lower than that of the raw DAAF,and comparable to that of the refined DAAF by conventional spraying crystallization method.This study provides an efficient method to fabricate u-DAAF with narrow particle size distribution and high reproducibility as well as a theoretical reference for fabrication of other ultrafine explosives.展开更多
This paper presents the basic principles of particle size measurement and latest industrial results recorded using an innovative optical instrumentation system designed to measure the size distribution of particles in...This paper presents the basic principles of particle size measurement and latest industrial results recorded using an innovative optical instrumentation system designed to measure the size distribution of particles in a pneumatic suspension.The system is non-intrusive and cost-effective.A low-cost CCD camera is used to capture images of the particulate flow field,which is illuminated by a low-cost pulsed laser sheet generator.The particle size distribution is then determined by processing the particle images through the use of novel processing algorithms.Experimental results obtained in the past on a small scale particle flow test rig have demonstrated that the system is capable of measuring the size distribution of pneumatically conveyed particles with an accuracy of a few percent.For the present paper results obtained when testing the system at a 4 MW industrial test facility are presented.Comparisons are made with both off-line reference data achieved through sieving and on-line laser diffraction data recorded using an intrusive,extractive,Malvern Instruments system.In general there is good agreement between results when considering the characteristics and limitations of the individual methodologies.The novel imaging system shows itself to be rugged,practical and useful under genuine industrial conditions.展开更多
Grain size distribution of bed material is an important characteristic for studying evolution of natural river channel by means of experimental ways and numerical modeling of flow and sediment process.In this study,th...Grain size distribution of bed material is an important characteristic for studying evolution of natural river channel by means of experimental ways and numerical modeling of flow and sediment process.In this study,the fractal characteristic of sediment particle has been defined by means of fractal theory based on ana- lyzing the property of grain size distribution of bed material in the river channel.Furthennore,the fractal prop- erty of sediment particle has been applied to judge the process of armorin...展开更多
基金Project supported by Technology Development and Research Special Foundation of National Science Research Academicand Institute , China
文摘Based on various ultrasonic loss mechanisms, the formula of the cumulative mass percentage of minerals with different particle sizes was given, with which the particle size distribution was integrated into an ultrasonic attenuation model. And then the correlations between the ultrasonic attenuation and the pulp density, and the particle size were obtained. The derived model was combined with the experiment and the analysis of experimental data to determine the inverse model relating ultrasonic attenuation coefficient with size distribution. Finally, an optimization method of inverse parameter, genetic algorithm was applied for particle size distribution. The results of inverse calculation show that the precision of measurement was high.
基金the National Natural Science Foundation of China (Grant No.22105184)Research Fund of SWUST for PhD (Grant No.22zx7175)+1 种基金Sichuan Science and Technology Program (Grant No.2019ZDZX0013)Institute of Chemical Materials Program (Grant No.SXK-2022-03)for financial support。
文摘High purity and ultrafine DAAF(u-DAAF)is an emerging insensitive charge in initiators.Although there are many ways to obtain u-DAAF,developing a preparation method with stable operation,accurate control,good quality consistency,equipment miniaturization,and minimum manpower is an inevitable requirement to adapt to the current social technology development trend.Here reported is the microfluidic preparation of u-DAAF with tunable particle size by a passive swirling microreactor.Under the guidance of recrystallization growth kinetics and mixing behavior of fluids in the swirling microreactor,the key parameters(liquid flow rate,explosive concentration and crystallization temperature)were screened and optimized through screening experiments.Under the condition that no surfactant is added and only experimental parameters are controlled,the particle size of recrystallized DAAF can be adjusted from 98 nm to 785 nm,and the corresponding specific surface area is 8.45 m^(2)·g^(-1)to 1.33 m^(2)·g^(-1).In addition,the preparation method has good batch stability,high yield(90.8%-92.6%)and high purity(99.0%-99.4%),indicating a high practical application potential.Electric explosion derived flyer initiation tests demonstrate that the u-DAAF shows an initiation sensitivity much lower than that of the raw DAAF,and comparable to that of the refined DAAF by conventional spraying crystallization method.This study provides an efficient method to fabricate u-DAAF with narrow particle size distribution and high reproducibility as well as a theoretical reference for fabrication of other ultrafine explosives.
文摘This paper presents the basic principles of particle size measurement and latest industrial results recorded using an innovative optical instrumentation system designed to measure the size distribution of particles in a pneumatic suspension.The system is non-intrusive and cost-effective.A low-cost CCD camera is used to capture images of the particulate flow field,which is illuminated by a low-cost pulsed laser sheet generator.The particle size distribution is then determined by processing the particle images through the use of novel processing algorithms.Experimental results obtained in the past on a small scale particle flow test rig have demonstrated that the system is capable of measuring the size distribution of pneumatically conveyed particles with an accuracy of a few percent.For the present paper results obtained when testing the system at a 4 MW industrial test facility are presented.Comparisons are made with both off-line reference data achieved through sieving and on-line laser diffraction data recorded using an intrusive,extractive,Malvern Instruments system.In general there is good agreement between results when considering the characteristics and limitations of the individual methodologies.The novel imaging system shows itself to be rugged,practical and useful under genuine industrial conditions.
基金Supported by National Nature Science Foundation of China(Grant 50409012).
文摘Grain size distribution of bed material is an important characteristic for studying evolution of natural river channel by means of experimental ways and numerical modeling of flow and sediment process.In this study,the fractal characteristic of sediment particle has been defined by means of fractal theory based on ana- lyzing the property of grain size distribution of bed material in the river channel.Furthennore,the fractal prop- erty of sediment particle has been applied to judge the process of armorin...
