Nanotechnology has played an influential role in improving the energetic content without subsiding the performance of high energy materials in the current era.In this work,HMX(octahydro-1,3,5,7-tetranitro-1,3,5,7-tetr...Nanotechnology has played an influential role in improving the energetic content without subsiding the performance of high energy materials in the current era.In this work,HMX(octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine)nanoparticles were prepared by sonochemically assisted solvent-antisolvent spray technique focussing the reduction in its size so as to improve its energetic properties.In order to fabricate nano HMX various parameters such as different solvents and temperature were investigated.Sonication is one of the strategies recently explored in this regard;so time dependent study of sonication using probe sonicator was performed.It has been postulated that bubble formed during sonication when collapses generate high temperature and many nucleation sites which leads to the formation of uniform spherical particles with small size and fast transition phase.XRD studies depicted phase transformation from a toβas a result of sonication.The TEM images revealed that the rise in the sonication time resulted into decrease in the particle size from 300 to 10 nm.Differential scanning calorimetry(DSC)was employed to determine the heat release of the samples and enhancement in the heat release with the decrease in the particle size.A decrease in the spark sensitivity was observed from 2 J(regular HMX)to 50 mJ(nano HMX).展开更多
Emulsions are inherently thermodynamically unstable dispersions that are widely involved in food processing,cosmetic preparation,and drug delivery.The existing ultrasonic emulsification techniques mainly rely on the d...Emulsions are inherently thermodynamically unstable dispersions that are widely involved in food processing,cosmetic preparation,and drug delivery.The existing ultrasonic emulsification techniques mainly rely on the direct contact between the sonicator probe and liquids,which causes localized high temperature and pressure within the liquid and influences the final properties of the obtained emulsion.In this work,a containerless emulsification approach has been realized by using ultrasonic levitation.The emulsification of water‒oil system can be promoted by adjusting the emitter‒reflector distance to alter the acoustic radiation pressure on the surface of the levitated drop.The dynamic behaviors of the emulsification process were monitored by using a high-speed camera,and the sound field was analyzed via numerical simu-lation.The experimental results showed that atomization of droplets driven by sound field was the main driving force for emulsification.This method can be used to pre-pare emulsions in which the average diameter of the droplets was about 2–3µm.The work provided a new method for containerless emulsification,thus shedding light on the preparation of contamination-free pharmaceuticals.展开更多
基金ER&IPR,DRDO,New Delhi for funding the project “DRDO-DIAT Programme on Nanomaterials”
文摘Nanotechnology has played an influential role in improving the energetic content without subsiding the performance of high energy materials in the current era.In this work,HMX(octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine)nanoparticles were prepared by sonochemically assisted solvent-antisolvent spray technique focussing the reduction in its size so as to improve its energetic properties.In order to fabricate nano HMX various parameters such as different solvents and temperature were investigated.Sonication is one of the strategies recently explored in this regard;so time dependent study of sonication using probe sonicator was performed.It has been postulated that bubble formed during sonication when collapses generate high temperature and many nucleation sites which leads to the formation of uniform spherical particles with small size and fast transition phase.XRD studies depicted phase transformation from a toβas a result of sonication.The TEM images revealed that the rise in the sonication time resulted into decrease in the particle size from 300 to 10 nm.Differential scanning calorimetry(DSC)was employed to determine the heat release of the samples and enhancement in the heat release with the decrease in the particle size.A decrease in the spark sensitivity was observed from 2 J(regular HMX)to 50 mJ(nano HMX).
基金National Natural Science Foundation of China,Grant/Award Numbers:12272314,11972303State Key Laboratory of Solidification Processing,Northwestern Polytechnical University,Grant/Award Number:SKLSP202001。
文摘Emulsions are inherently thermodynamically unstable dispersions that are widely involved in food processing,cosmetic preparation,and drug delivery.The existing ultrasonic emulsification techniques mainly rely on the direct contact between the sonicator probe and liquids,which causes localized high temperature and pressure within the liquid and influences the final properties of the obtained emulsion.In this work,a containerless emulsification approach has been realized by using ultrasonic levitation.The emulsification of water‒oil system can be promoted by adjusting the emitter‒reflector distance to alter the acoustic radiation pressure on the surface of the levitated drop.The dynamic behaviors of the emulsification process were monitored by using a high-speed camera,and the sound field was analyzed via numerical simu-lation.The experimental results showed that atomization of droplets driven by sound field was the main driving force for emulsification.This method can be used to pre-pare emulsions in which the average diameter of the droplets was about 2–3µm.The work provided a new method for containerless emulsification,thus shedding light on the preparation of contamination-free pharmaceuticals.
