Nanoparticle generation using corona discharge ions from a supersonic flow in low pressure

Jung, Jae Hee; Kim, Sang Bok; Kim, Sang Soo

doi:10.1016/j.powtec.2007.09.019

Cited by 9 publications

(5 citation statements)

References 35 publications

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“…In this case, cooling is not the main concern but the collimation property is used to optimize the thrust of the gas to the ground thus improving takeoff. Laval nozzles are important tools in other fields such as powder metallurgy, including gas-assisted atomization (Allimant et al, 2009 andSi et al, 2014), narrow size nanoparticle synthesis (Li et al, 2008 andJung et al, 2008), or inertial separation of particles (Kanaoka et al, 2001). These type of nozzles can be found as well as part of apparatuses developed for studies concerning spray deposition (Jen et al, 2006), formation of super thin fibers (Blim et al, 2014), hydrogen production (Du et al, 2012), laser cutting (Man et al, 1999), homogeneous or binary nucleation (Kim et al, 2004 andTanimura et al, 2010), infrared (Tanimura et al, 1996 andBenidar et al, 2000) or microwave spectroscopy (Oldham et al, 2014), or hypersonic astrophysical jets simulations (Tordella et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Development of a pulsed uniform supersonic gas expansion system based on an aerodynamic chopper for gas phase reaction kinetic studies at ultra-low temperatures

Jiménez

Ballesteros

Canosa

et al. 2015

Review of Scientific Instruments

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A detailed description of a new pulsed supersonic uniform gas expansion system is presented together with the experimental validation of the setup by applying the CRESU (French acronym for Cinétique de Réaction en Ecoulement Supersonique Uniforme or Reaction Kinetics in a Uniform Supersonic Flow) technique to the gas-phase reaction of OH radicals with 1-butene at ca. 23 K and 0.63 millibars of helium (carrier gas). The carrier gas flow, containing negligible mixing ratios of OH-precursor and 1-butene, is expanded from a high pressure reservoir (337 millibars) to a low pressure region (0.63 millibars) through a convergent-divergent nozzle (Laval type). The novelty of this experimental setup is that the uniform supersonic flow is pulsed by means of a Teflon-coated aerodynamic chopper provided with two symmetrical apertures. Under these operational conditions, the designed Laval nozzle achieves a temperature of (22.4 ± 1.4) K in the gas jet. The spatial characterization of the temperature and the total gas density within the pulsed uniform supersonic flow has also been performed by both aerodynamical and spectroscopic methods. The gas consumption with this technique is considerably reduced with respect to a continuous CRESU system. The kinetics of the OH+1-butene reaction was investigated by the pulsed laser photolysis/laser induced fluorescence technique. The rotation speed of the disk is temporally synchronized with the exit of the photolysis and the probe lasers. The rate coefficient (k(OH)) for the reaction under investigation was then obtained and compared with the only available data at this temperature.

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Section: Introductionmentioning

confidence: 99%

Development of a pulsed uniform supersonic gas expansion system based on an aerodynamic chopper for gas phase reaction kinetic studies at ultra-low temperatures

Jiménez

Ballesteros

Canosa

et al. 2015

Review of Scientific Instruments

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“…Silver (Ag) is generally known as a safe material with a wide antibacterial spectrum. − It is a relatively nontoxic and natural inorganic metal. Nanoscale particles possess a larger total surface area per unit volume than does bulk material.…”

Section: Introductionmentioning

confidence: 99%

Preparation of Airborne Ag/CNT Hybrid Nanoparticles Using an Aerosol Process and Their Application to Antimicrobial Air Filtration

et al. 2011

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Carbon nanotubes (CNTs) have been widely used in a variety of applications because of their unique structure and excellent mechanical and electrical properties. Additionally, silver (Ag) nanoparticles exhibit broad-spectrum biocidal activity toward many different bacteria, fungi, and viruses. In this study, we prepared Ag-coated CNT hybrid nanoparticles (Ag/CNTs) using aerosol nebulization and thermal evaporation/condensation processes and tested their usefulness for antimicrobial air filtration. Droplets were generated from a CNT suspension using a six-jet collison nebulizer, passed through a diffusion dryer to remove moisture, and entered a thermal tube furnace where silver nanoparticles were generated by thermal evaporation/condensation at ∼980 °C in a nitrogen atmosphere. The CNT and Ag nanoparticle aerosols mixed together and attached to each other, forming Ag/CNTs. For physicochemical characterization, the Ag/CNTs were introduced into a scanning mobility particle sizer (SMPS) for size distribution measurements and were sampled by the nanoparticle sampler for morphological and elemental analyses. For antimicrobial air filtration applications, the airborne Ag/CNT particles generated were deposited continuously onto an air filter medium. Physical characteristics (fiber morphology, pressure drop, and filtration efficiency) and biological characteristics (antimicrobial tests against Staphylococcus epidermidis and Escherichia coli bioaerosols) were evaluated. Real-time SMPS and transmission electron microscopy (TEM) data showed that Ag nanoparticles that were <20 nm in diameter were homogeneously dispersed and adhered strongly to the CNT surfaces. Because of the attachment of Ag nanoparticles onto the CNT surfaces, the total particle surface area concentration measured by a nanoparticle surface area monitor (NSAM) was lower than the summation of each Ag nanoparticle and CNT generated. When Ag/CNTs were deposited on the surface of an air filter medium, the antimicrobial activity against test bacterial bioaerosols was enhanced, compared with the deposition of CNTs or Ag nanoparticles alone, whereas the filter pressure drop and bioaerosol filtration efficiency were similar to those of CNT deposition only. At a residence time of 2 h, the relative microbial viabilities of gram-positive S. epidermidis were ∼32, 13, 5, and 0.9% on the control, CNT-, Ag nanoparticle-, and Ag/CNT-deposited filters, respectively, and those of gram-negative E. coli were 13, 2.1, 0.4, and 0.1% on the control, CNTs, Ag nanoparticles, and Ag/CNTs, respectively. These Ag/CNT hybrid nanoparticles may be useful for applications in biomedical devices and antibacterial control systems.

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“…For instance, presently the most reliable method for measuring the particle size distribution of submicron aerosols is by differential mobility analysis, which requires the particles to be charged with a known charge distribution (Flagan 2001). Other examples where particle charging is needed are electrical detection of particles, as in smoke detectors; electrostatic precipitation for contamination control (Lawless and Sparks 1988); deposition of nanoparticles in selective locations for fabrication of nanostructures (Kim et al 2006;Lee et al 2011); reduction of the coagulation rate to produce higher concentrations of nanoparticles (Park et al 2014;Jung et al 2008);etc. There are several mechanisms by which aerosol particles can acquire a net charge; of these, the two most important for applications are field charging and diffusion charging (Friedlander 2000). Field charging is only important for large particles, say those with diameter above 1 lm.…”

Section: Introductionmentioning

confidence: 99%

High-efficiency electrical charger for nanoparticles

Alonso¹,

Huang

2015

J Nanopart Res

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Nanoparticle generation using corona discharge ions from a supersonic flow in low pressure

Cited by 9 publications

References 35 publications

Development of a pulsed uniform supersonic gas expansion system based on an aerodynamic chopper for gas phase reaction kinetic studies at ultra-low temperatures

Development of a pulsed uniform supersonic gas expansion system based on an aerodynamic chopper for gas phase reaction kinetic studies at ultra-low temperatures

Preparation of Airborne Ag/CNT Hybrid Nanoparticles Using an Aerosol Process and Their Application to Antimicrobial Air Filtration

High-efficiency electrical charger for nanoparticles

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