Bipolar Coagulation Process for the Production of Powders

Camelot, D.; Marijnissen, J.C.M.; Scarlett, B. Florence

doi:10.1021/ie980435j

Cited by 18 publications

(11 citation statements)

References 16 publications

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“…Other problems also exist, such as the application in inertial sensing, where the flow must be able to freely vibrate in 3-D space under inertial force, which is, however, dominated by electrostatic force in limited space [38]- [43]. In bioapplications, the aerosol particles with highly reactive ionization products are destructive for living cells, spore, or viruses; therefore, neutralization with gaseous counter-ions or corona neutralizer is attractive for the formation of mildly charged aerosol [44]- [46]. Other applications of neutralized ion wind are for circulatory flow [47]- [49], electrospun polymer nanofiber to overcome the intrinsically instability of the process [50], pharmaceutical inhalation aerosol by bipolarly charged particles [51], or to generate mildly charged particles for insecticide dispensing [52].…”

Section: Introductionmentioning

confidence: 99%

Ion Wind Generator Utilizing Bipolar Discharge in Parallel Pin Geometry

Dau

Dinh

Terebessy³

et al. 2016

IEEE Trans. Plasma Sci.

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We present a simple and efficient airflow generator utilizing the effect of ion wind by generating simultaneously both the positive and negative ions from two sharp electrodes mounted parallel to each other. The unique bipolar geometrical setup eliminates the effect of space charge by the high recombination rate of oppositely charged ions. The two-electrode arrangement is symmetrical, where the electrode creating charged ions of one polarity also serves as the reference electrode to establish the electric field required for ion creation by the opposite electrode, and vice versa. Unlike the conventional setup, with a single electrode generating ion wind with movement toward the reference electrode, in this configuration the air movement is parallel to the electrodes, and is directed away from the device. The airflow behavior is studied by both experiments and numerical simulation. The ion wind speed has a linear relationship with the square root of the discharge current, U ∝ √ I, and its measured values agree well with simulation. The characterization of the discharge current-voltage relationship was derived from mathematical processing in the general formThe ion wind speed and the current-voltage characteristics depend on the interspace between the electrodes and the electrode geometry. An ion wind speed on the order of ms −1 is created with a microampere discharge current, resulting in a total net charge of only several femtoampere. The proposed configuration is beneficial in minimizing the power consumption of the system, and in enabling air recirculation for airflow control applications, cooling applications, propulsion technology, and micropump design, especially for the applications where neutralized ion wind flow is required.Index Terms-Bipolar corona discharge, electrohydrodynamics, ion wind, parallel pin.0093-3813 of Engineering and Technology, VNUH. He has authored or co-authored more than 60 scientific articles and seven inventions. His current research interests include 3-D system integration technology and MEMS-based sensors, actuators, and applications.

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Section: Introductionmentioning

confidence: 99%

Ion Wind Generator Utilizing Bipolar Discharge in Parallel Pin Geometry

Dau

Dinh

Terebessy³

et al. 2016

IEEE Trans. Plasma Sci.

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“…The possibility of utilizing bipolar coagulation of particles generated by two electrospray heads in the powder production has further been explored (Borra et al, 1999;Camelot et al, 1999). Each of two electrospray heads in their system generated monodisperse droplets from one reaction precursor.…”

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confidence: 99%

Performance study of a twin-head electrospray system

Liu

Chen

2012

Journal of Aerosol Science

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“…If they are directed towards each other coagulation between the droplets takes place through the electrical attraction between them (Bipolar Coagulation). In this case, droplets of different composition can be mixed and reacted to form composite or new materials (Camelot 1999). The coagulation can also be used just to neutralize the droplets.…”

Section: Ehda Configurationsmentioning

confidence: 99%

“…As already mentioned, the process of bipolar coagulation (Camelot 1999), where two sprays of oppositely charged droplets are directed towards each other and the coagulation between the droplets takes place through the electrical attraction between them can also be used to produce drug particles, see Fig. 11.…”

Section: Carrier Particle and Drug Particle Productionmentioning

confidence: 99%

Producing Pharmaceutical Particles via Electrospraying with an Emphasis on Nano and Nano Structured Particles - A Review

Yurteri

Hartman

Marijnissen

2010

KONA

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Recent advances in nanotechnology offer nano sized or nanostructured pharmaceutical particles, being as small as the size of cells such as receptors or nucleic acids, which can be engineered to provide enhanced efficacy, solubility, or biocompatibility, and to administer at much lower dosages. However, industrial production of these particles is still challenging. Among different techniques, aerosol based ones might be favorable since they are considered as contamination free processes and do not interfere with complex molecules of drugs. We, in this review, consider liquid atomization, where droplet formation is followed by conversion into solid particles. The best candidate is a method, which not only produces mono sized droplets with a diameter smaller than the inside nozzle diameter but also generates small enough start up sizes. Such a method is found in: Electro-Hydrodynamic Atomization (EHDA) or Electrospraying. Electrospraying is now a well practiced technique for producing very fine monodisperse droplets from a liquid under the influence of electrical forces. By controlling the liquid flow rate and the electrostatic potential between the liquid and the counter electrode, droplets within a narrow size range can be generated, while the mean diameter ranges from nanometers up to several micrometers. Besides generating monodisperse droplets, electrosprays are also distinguished by their self dispersing nature due to Coulomb repulsion, the possibility of trajectory control of the produced charged droplets, and the reduced risk of nozzle clogging due to the large size of the orifice compared to the size of the droplets. We will discuss different spraying modes depending on the strength of the electric stresses relative to the surface tension stress on the liquid surface and on the inertia of the liquid leaving the nozzle. However, for the production of monodisperse nanoparticles the so called cone-jet mode will be explained in depth. Scaling laws can be used to estimate the operational conditions for producing nanodroplets of a certain size. Hartman and coworkers refined the scaling laws for EHDA in the Cone-Jet mode using theoretically derived models for the cone, jet, and droplet size. By means of several examples, a generic way to produce nanoparticles, via scaling laws, from a multitude of different precursors will be discussed. Several examples of medicine particles with different properties made by EHDA will be given. Processes based on bipolar coagulation, where oppositely charged carrier particles and nano sized active agents are brought together to form composite drugs, will be discussed. Finally some attention will be given to challenges on out-scaling of EHDA methods for industrial production.

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Bipolar Coagulation Process for the Production of Powders

Cited by 18 publications

References 16 publications

Ion Wind Generator Utilizing Bipolar Discharge in Parallel Pin Geometry

Ion Wind Generator Utilizing Bipolar Discharge in Parallel Pin Geometry

Performance study of a twin-head electrospray system

Producing Pharmaceutical Particles via Electrospraying with an Emphasis on Nano and Nano Structured Particles - A Review

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