@article{park_reduction_2002,
title = {Reduction of electrostatic charges in gas–solid fluidized beds},
volume = {57},
issn = {0009-2509},
url = {http://www.sciencedirect.com/science/article/pii/S0009250901003529},
doi = {10.1016/S0009-2509(01)00352-9},
abstract = {Reduction of electrostatic charge accumulation by increasing the humidity of fluidizing gas was investigated using single bubble injection in two- and three-dimensional fluidized beds. Both 321 μm glass beads and 378 μm polyethylene particles were found to be charged positively when fluidized by air. Electrostatic charges increased as the bubble size increased. Increasing the relative humidity of the fluidizing air to 40–80\% reduced the accumulation of electrostatic charge by increasing the surface conductivity, thereby enhancing charge dissipation.},
number = {1},
urldate = {2015-09-14},
journal = {Chemical Engineering Science},
author = {Park, Ah-Hyung and Bi, Hsiaotao and Grace, John R},
month = jan,
year = {2002},
keywords = {Anti-static, Charge, Electrostatic, Fluidization, Humidity, Multiphase flow},
pages = {153--162},
file = {ScienceDirect Full Text PDF:/home/shakti/jarik/.mozilla/firefox/6v5y0jfw.default/zotero/storage/KIVBBV26/Park et al. - 2002 - Reduction of electrostatic charges in gas–solid fl.pdf:application/pdf;ScienceDirect Snapshot:/home/shakti/jarik/.mozilla/firefox/6v5y0jfw.default/zotero/storage/UJXJW6C7/S0009250901003529.html:text/html}
}
@article{lowell_contact_1980,
title = {Contact electrification},
volume = {29},
issn = {0001-8732},
url = {http://dx.doi.org/10.1080/00018738000101466},
doi = {10.1080/00018738000101466},
abstract = {If two materials are brought into contact and then separated they are found to be charged; this is the phenomenon of ‘contact electrification’. The subject falls naturally into three divisions—electrification of metals by metals; of insulators by metals; and of insulators by insulators. The first of these is well understood; charge transfer between metals is such as to bring the two Fermi levels into coincidence. The second division, electrification of insulators by metals, has been much studied recently and takes up the main part of our review; our understanding remains imperfect, chiefly because of lack of knowledge about the relevant electron states in insulators. Electrification of insulators by insulators has not been studied so extensively, but there is evidence that an understanding of the metal/insulator case will lead to an understanding of the insulator/insulator case as well.},
number = {6},
urldate = {2015-09-15},
journal = {Advances in Physics},
author = {Lowell, J. and Rose-Innes, A. C.},
month = dec,
year = {1980},
pages = {947--1023},
file = {Full Text PDF:/home/shakti/jarik/.mozilla/firefox/6v5y0jfw.default/zotero/storage/WCDEMDAT/Lowell and Rose-Innes - 1980 - Contact electrification.pdf:application/pdf;Snapshot:/home/shakti/jarik/.mozilla/firefox/6v5y0jfw.default/zotero/storage/SXNXE3T6/00018738000101466.html:text/html}
}
@article{rokkam_computational_2010,
title = {Computational fluid dynamics and electrostatic modeling of polymerization fluidized-bed reactors},
volume = {203},
issn = {0032-5910},
url = {http://www.sciencedirect.com/science/article/pii/S0032591010001828},
doi = {10.1016/j.powtec.2010.04.002},
abstract = {Electrostatics plays an important role in gas–solid polymerization fluidized-bed reactors. Agglomeration of polymer particles can occur due to either electrostatic and/or thermal effects, and can lead to reactor operability problems if not properly mitigated. In this work a first-principles electrostatic model is developed and coupled with a multi-fluid computational fluid dynamic (CFD) model to understand the effect of electrostatics on the bulk polymer, polymer fines, and catalyst particles. The multi-phase CFD model for gas–solid flow is based on the kinetic theory of granular flows and the frictional theory. The electrostatic model is developed based on a fixed, size-dependent charge for each type of particle (catalyst, polymer fines and polymer). The combined CFD model is first verified using simple test cases and then applied to a pilot-plant-scale polymerization fluidized-bed reactor. The multi-phase CFD model is applied to reproduce qualitative trends in particle segregation and entrainment due to electrostatic charges observed in experiments.},
number = {2},
urldate = {2015-09-14},
journal = {Powder Technology},
author = {Rokkam, Ram G. and Fox, Rodney O. and Muhle, Michael E.},
month = nov,
year = {2010},
keywords = {Electrostatic modeling, Euler–Euler model, Fluidized-bed reactors, Multi-fluid model, Olefin polymerization, Segregation},
pages = {109--124},
file = {ScienceDirect Full Text PDF:/home/shakti/jarik/.mozilla/firefox/6v5y0jfw.default/zotero/storage/N6VFSSTP/Rokkam et al. - 2010 - Computational fluid dynamics and electrostatic mod.pdf:application/pdf;ScienceDirect Snapshot:/home/shakti/jarik/.mozilla/firefox/6v5y0jfw.default/zotero/storage/7C6XHZIU/S0032591010001828.html:text/html}
}
@article{salama_investigation_2013,
title = {Investigation of electrostatic charge distribution within the reactor wall fouling and bulk regions of a gas–solid fluidized bed},
volume = {71},
issn = {0304-3886},
url = {http://www.sciencedirect.com/science/article/pii/S0304388612001167},
doi = {10.1016/j.elstat.2012.11.002},
abstract = {The distribution of charge within the wall fouling region and bulk of a fluidized bed reactor was investigated. Experiments were conducted in a 0.1 m in diameter carbon steel fluidization column under atmospheric conditions. Polyethylene particles were fluidized with extra dry air at 1.5 the minimum fluidization velocity (bubbling flow regime) for 1 h. Using an online Faraday cup measurement technique, the net charge-to-mass ratio (q/m), as well as the size distribution of all particles adhered to the column wall and those in the bulk of the bed was determined. The wall particles were found to be predominantly negatively charged while those which did not adhere to the wall were predominantly positively charged. The charge distribution within each region was then investigated by a custom made charged particle separator that separated the particles according to their charge magnitude and polarity. It was determined that although the net charge of the wall layer particles was negative, a significant amount of positively charged particles existed within each sample and therefore the entire wall particle layer. This suggests that the wall layer was formed through layering between positively and negatively charged particles. Particles in the bulk of the bed also consisted of bipolarly charged particles.},
number = {1},
urldate = {2015-09-14},
journal = {Journal of Electrostatics},
author = {Salama, Fawzi and Sowinski, Andrew and Atieh, Khaled and Mehrani, Poupak},
month = feb,
year = {2013},
keywords = {bipolar charging, Electrostatic charge generation, Gas–solid fluidization, Triboelectrification},
pages = {21--27},
file = {ScienceDirect Snapshot:/home/shakti/jarik/.mozilla/firefox/6v5y0jfw.default/zotero/storage/ITQ8687G/S0304388612001167.html:text/html}
}
@article{hassani_numerical_2013,
title = {Numerical investigation of effect of electrostatic forces on the hydrodynamics of gas–solid fluidized beds},
volume = {246},
issn = {0032-5910},
url = {http://www.sciencedirect.com/science/article/pii/S0032591013003537},
doi = {10.1016/j.powtec.2013.05.007},
abstract = {A 3D discrete element method (DEM) coupled with computational fluid dynamics (CFD) model was developed for studying the effect of electrostatic forces between particles on fluidization hydrodynamics. To validate this code, bubble diameters in the single bubble injection and freely bubbling regimes were compared with experimental values and acceptable agreement was observed. The simulation results showed that by increasing the charge of mono-charged particles into the bed, the bubble size and solid diffusion coefficient decrease and distribution of porosity and particles circulation also change and bed tends toward more homogeneity. By adding bipolar charged particles into the bed, bubble size, solids diffusivity and voidage distribution approach to that of the neutral bed and particles tend to form chains of connected particles.},
urldate = {2015-09-14},
journal = {Powder Technology},
author = {Hassani, M. A. and Zarghami, R. and Norouzi, H. R. and Mostoufi, N.},
month = sep,
year = {2013},
keywords = {Computational fluid dynamics, Discrete element method, Electrostatic force, Fluidized bed, mixing},
pages = {16--25},
file = {ScienceDirect Full Text PDF:/home/shakti/jarik/.mozilla/firefox/6v5y0jfw.default/zotero/storage/CSCBJINM/Hassani et al. - 2013 - Numerical investigation of effect of electrostatic.pdf:application/pdf;ScienceDirect Snapshot:/home/shakti/jarik/.mozilla/firefox/6v5y0jfw.default/zotero/storage/PZHSBEN9/S0032591013003537.html:text/html}
}
@article{hendrickson_electrostatics_2006,
title = {Electrostatics and gas phase fluidized bed polymerization reactor wall sheeting},
volume = {61},
issn = {0009-2509},
url = {http://www.sciencedirect.com/science/article/pii/S0009250905006433},
doi = {10.1016/j.ces.2005.07.029},
abstract = {Reduction of electrostatic charge accumulation in fluidized bed polymerization reactors can reduce the frequency of reactor wall sheeting incidents and decrease the cost of operating fluidized bed polymerization reactors. The accumulation of excess electrostatic charge in fluidized bed polymerization reactors causes the fluidized polymer particles to adhere to the reactor wall and form wall sheets. Reactor wall sheets are described in order to characterize the problem. Electrostatic forces are compared to other forces influencing fluidization, such as drag forces and van der Waals forces. Literature values of measured particle electrostatic charges are compared to the maximum theoretical values predicted by Gauss’ law applied to the particles and to the entire fluidized bed. Electrostatic charge mitigation techniques are reviewed and future research areas are suggested based on the theoretical analysis and identified knowledge gaps.},
number = {4},
urldate = {2015-09-14},
journal = {Chemical Engineering Science},
author = {Hendrickson, Gregory},
month = feb,
year = {2006},
keywords = {Chemical reactors, Electrostatics, Fluidization, Polymerization, Powder technology, Processing},
pages = {1041--1064},
file = {ScienceDirect Full Text PDF:/home/shakti/jarik/.mozilla/firefox/6v5y0jfw.default/zotero/storage/MXIFFVFU/Hendrickson - 2006 - Electrostatics and gas phase fluidized bed polymer.pdf:application/pdf;ScienceDirect Snapshot:/home/shakti/jarik/.mozilla/firefox/6v5y0jfw.default/zotero/storage/ATEKM2H3/S0009250905006433.html:text/html}
}
@article{sowinski_effect_2012,
title = {Effect of fluidizing particle size on electrostatic charge generation and reactor wall fouling in gas–solid fluidized beds},
volume = {71},
issn = {0009-2509},
url = {http://www.sciencedirect.com/science/article/pii/S000925091100830X},
doi = {10.1016/j.ces.2011.11.031},
abstract = {Electrostatic charge generation from particle–particle and particle–wall contacts in gas–solid fluidized beds is virtually unavoidable and generally undesired. Charged particles are known to cause problems including particle agglomeration and particle–reactor wall adhesion. The polymerization industry has been plagued by reactor wall fouling for many years, but the actual mechanism behind this problem is not well understood. The wide particle size distribution present in polyolefin fluidized bed reactors is believed to play an important role. This work studied the effect of particle size of a polyethylene resin received directly from industrial reactors on electrostatic charge generation and reactor wall fouling. The resin was sieved into five different narrowed particle size fractions and fluidized at two different gas velocities; 1.5 and 4 times the minimum fluidization velocity (umf) representing the bubbling and the slugging flow regimes. The fluidization was performed in a 0.1 m carbon steel fluidization column with the charge measurement technique described by Sowinski et al. (2010). In the bubbling flow regime significant particle wall adhesion was found for particles sizes up to 600 μm, after which very little reactor wall fouling was observed. In the slugging flow regime, there was significant particle wall adhesion for all particle size fractions tested with the exception of the 600–710 μm range, which at times resulted in significant particle–wall adhesion and in other times none was obtained. Overall, it was found that the smaller particles had a higher charge and resulted in more reactor wall fouling. With the non-sieved resin, the particles that adhered to the column wall were approximately of the same size as the smallest size fraction tested (300–425 μm). This study found that the measurement of the net charge-to-mass ratio inside a fluidized bed is not an indication of the amount of reactor wall fouling.},
urldate = {2015-09-14},
journal = {Chemical Engineering Science},
author = {Sowinski, Andrew and Mayne, Antonio and Mehrani, Poupak},
month = mar,
year = {2012},
keywords = {Electrostatics, Fouling, Gas–solid fluidization, Particle charging, Polymer processing, Powder technology},
pages = {552--563},
file = {ScienceDirect Full Text PDF:/home/shakti/jarik/.mozilla/firefox/6v5y0jfw.default/zotero/storage/KZZI3KVD/Sowinski et al. - 2012 - Effect of fluidizing particle size on electrostati.pdf:application/pdf;ScienceDirect Snapshot:/home/shakti/jarik/.mozilla/firefox/6v5y0jfw.default/zotero/storage/C27KZSI5/S000925091100830X.html:text/html}
}
@article{lacks_contact_2011,
title = {Contact electrification of insulating materials},
volume = {44},
issn = {0022-3727, 1361-6463},
url = {http://stacks.iop.org/0022-3727/44/i=45/a=453001?key=crossref.961491dbae3893f93ad5fd5cbd358dad},
doi = {10.1088/0022-3727/44/45/453001},
number = {45},
urldate = {2015-09-14},
journal = {Journal of Physics D: Applied Physics},
author = {Lacks, Daniel J and Mohan Sankaran, R},
month = nov,
year = {2011},
pages = {453001}
}
@article{murtomaa_electrostatic_2003,
title = {Electrostatic measurements on a miniaturized fluidized bed},
volume = {57},
issn = {0304-3886},
url = {http://www.sciencedirect.com/science/article/pii/S0304388602001213},
doi = {10.1016/S0304-3886(02)00121-3},
abstract = {In the pharmaceutical industry fluidization is often used in drying, coating and granulation processes. During fluidization powder particles contact other particles as well as the walls of the vessel and this leads to generation of electric charges. These charges may result in sparks, dust explosions, fires, reduced process efficiency and particle accumulation on the walls. However, the mechanism of the charging is not well understood. In this paper, an inductive method for charge generation measurement is presented. The system consists of an electrostatic ring probe, which allows charge scanning across the miniaturized fluidized bed without disturbing the fluidization process. The charge coupling from the system to the probe has been modelled and the experimental data have been simulated using an advanced field solving software. Experiments on lactose monohydrate, microcrystalline cellulose and glass beads have been performed and these results are presented.},
number = {1},
urldate = {2015-09-14},
journal = {Journal of Electrostatics},
author = {Murtomaa, Matti and Räsänen, Eetu and Rantanen, Jukka and Bailey, Adrian and Laine, Ensio and Mannermaa, Jukka-Pekka and Yliruusi, Jouko},
month = jan,
year = {2003},
keywords = {charge-to-mass ratio, Electrostatic charge, Electrostatic probe, Fluidized bed, Powder charging},
pages = {91--106},
file = {ScienceDirect Snapshot:/home/shakti/jarik/.mozilla/firefox/6v5y0jfw.default/zotero/storage/76E427HG/S0304388602001213.html:text/html}
}
@article{gouveia_electrostatic_2009,
title = {Electrostatic {Charging} of {Hydrophilic} {Particles} {Due} to {Water} {Adsorption}},
volume = {131},
issn = {0002-7863},
url = {http://dx.doi.org/10.1021/ja900704f},
doi = {10.1021/ja900704f},
abstract = {Kelvin force microscopy measurements on films of noncrystalline silica and aluminum phosphate particles reveal complex electrostatic potential patterns that change irreversibly as the relative humidity changes within an electrically shielded and grounded environment. Potential adjacent to the particle surfaces is always negative and potential gradients in excess of ±10 MV/m are found parallel to the film surface. These results verify the following hypothesis: the atmosphere is a source and sink of electrostatic charges in dielectrics, due to the partition of OH? and H+ ions associated to water adsorption. Neither contact, tribochemical or electrochemical ion or electron injection are needed to change the charge state of the noncrystalline hydrophilic solids used in this work.},
number = {32},
urldate = {2015-09-14},
journal = {Journal of the American Chemical Society},
author = {Gouveia, Rubia F. and Galembeck, Fernando},
month = aug,
year = {2009},
pages = {11381--11386},
file = {ACS Full Text PDF w/ Links:/home/shakti/jarik/.mozilla/firefox/6v5y0jfw.default/zotero/storage/Z59XGHMH/Gouveia and Galembeck - 2009 - Electrostatic Charging of Hydrophilic Particles Du.pdf:application/pdf;ACS Full Text Snapshot:/home/shakti/jarik/.mozilla/firefox/6v5y0jfw.default/zotero/storage/SHI7WQ23/ja900704f.html:text/html}
}
@article{laurentie_discrete_2013,
title = {Discrete element modeling of triboelectric charging of insulating materials in vibrated granular beds},
volume = {71},
issn = {0304-3886},
url = {http://www.sciencedirect.com/science/article/pii/S0304388613001034},
doi = {10.1016/j.elstat.2013.08.001},
abstract = {The triboelectric charging of granular insulating materials is very difficult to predict because of the complex physical mechanism involved in this process. The aim of this paper is to describe in detail the implementation of a numerical model of the tribocharging process taking place in vertically-vibrated beds of granular plastics. The charge exchanged in granule-to-granule and granule-to-wall collisions is computed by taking into account some electrical properties of the respective materials, their area of contact and the effect of the electric field generated by a system of high-voltage electrodes and by the charges of the granules themselves. The electrical model is coupled with the Discrete Element Method (DEM) which undertakes the whole granular dynamics and allows to compute accurately the contact surface of two colliding particles which is involved in the triboelectric charging model.
Beside the numerical simulations an experiment has been conducted with mixtures of mm-size polyamide and polycarbonate granules in a laboratory vibrated bed to validate the model. The numerical results have been found to be in good agreement with the experimental ones.},
number = {6},
urldate = {2015-09-14},
journal = {Journal of Electrostatics},
author = {Laurentie, J. C. and Traoré, P. and Dascalescu, L.},
month = dec,
year = {2013},
keywords = {Computational electrostatics, Discrete Element Method (DEM), Electrostatic processes, granular materials, Triboelectric charge, Vibrated beds},
pages = {951--957},
file = {ScienceDirect Snapshot:/home/shakti/jarik/.mozilla/firefox/6v5y0jfw.default/zotero/storage/MAB5PIF8/S0304388613001034.html:text/html}
}
@article{alissa_park_electrostatic_2007,
series = {Fluidized {Bed} {Applications}},
title = {Electrostatic charging phenomenon in gas–liquid–solid flow systems},
volume = {62},
issn = {0009-2509},
url = {http://www.sciencedirect.com/science/article/pii/S0009250906005495},
doi = {10.1016/j.ces.2006.08.058},
abstract = {During the operation of multiphase systems such as fluidized beds, electrostatic charges are generated when the materials involved are dielectric in nature. The accumulation of electrostatic charges within the system can be operationally hazardous. Work on understanding and, hence, preventing the electrostatic charging phenomena has mostly focused on gas–solid media. Relatively little study has been performed on particulates and multiphase systems with non-conductive liquids as the medium. In this study, electrostatic charging in gas–liquid–solid fluidized beds with liquid as the continuum phase under different operating conditions was explored. Two different charge-reducing methods were also evaluated. Based on experimental studies, it was found that the superficial gas and liquid velocities have a significant effect on the rate of charge generation and transfer in a three-phase fluidized bed because of variation in the frequency and the intensity of the particle collisions. The local number density of the particles also affected the distribution of the electrostatic signal obtained. Two methods of reducing electrostatic charge accumulation were also investigated: adding fine powder and adding an anti-static agent such as Larostat 264A. When 15 wt\% of fine glass powder was added to an air-Norpar15-HDPE (high density polyethylene) fluidized bed, the charge inside the fluidized bed was reduced by 72\%. When, on the other hand, as little as 0.5 wt\% of the anti-static agent, Larostat 264A in a liquid form, was added to the air-Norpar15-HDPE, the electrostatic level was quickly reduced by 83\% and within 1 h the electrostatic charge was completely eliminated from the system.},
number = {1–2},
urldate = {2015-09-14},
journal = {Chemical Engineering Science},
author = {Alissa Park, Ah-Hyung and Fan, Liang-Shih},
month = jan,
year = {2007},
keywords = {Agglomeration, Anti-static, Electrostatics, Fluidization, Multiphase flow, Particle},
pages = {371--386},
file = {ScienceDirect Full Text PDF:/home/shakti/jarik/.mozilla/firefox/6v5y0jfw.default/zotero/storage/XIV5CHGH/Alissa Park and Fan - 2007 - Electrostatic charging phenomenon in gas–liquid–so.pdf:application/pdf;ScienceDirect Snapshot:/home/shakti/jarik/.mozilla/firefox/6v5y0jfw.default/zotero/storage/R4GHC3JH/S0009250906005495.html:text/html}
}
@article{williams_triboelectric_2012,
title = {Triboelectric charging of insulating polymers–some new perspectives},
volume = {2},
issn = {2158-3226},
url = {http://scitation.aip.org/content/aip/journal/adva/2/1/10.1063/1.3687233},
doi = {10.1063/1.3687233},
abstract = {Tribolectric charging results from contact between surfaces, but precisely what is meant by each is not defined or understood, as they relate to charging. The recent microscopic evidence that contact charging can result from material transfer provides incentive to examine how contact charging is affected by these two factors. It is suggested that vigorous rubbing or pressing of two polymers results in transfer of deeper layers than would result from light contacts. Different layers can have substantially different compositions because polymers are typically not homogeneous as a function of depth, so contact and surface are related in this way. This could account for charge transfer between identical polymers, especially in asymmetric contacts in which the frictional force on one polymer differs from that on the other, so that material from different depths is transferred. This review outlines the roles of physics, chemistry and surfaceanalysis in sufficient detail to focus on these subjects. It also makes suggestions how these concepts could be applied to some of the current leading edge research in this area.},
number = {1},
urldate = {2015-09-14},
journal = {AIP Advances},
author = {Williams, Meurig W.},
month = mar,
year = {2012},
keywords = {Charge exchange reactions, charge transfer, polymers, Surface charge, surface composition},
pages = {010701},
file = {Full Text PDF:/home/shakti/jarik/.mozilla/firefox/6v5y0jfw.default/zotero/storage/F2HIN4IN/Williams - 2012 - Triboelectric charging of insulating polymers–some.pdf:application/pdf;Snapshot:/home/shakti/jarik/.mozilla/firefox/6v5y0jfw.default/zotero/storage/NXKTVMEW/1.html:text/html}
}
@article{williams_triboelectric_2011,
title = {Triboelectric {Charging} of {Insulators} \#x2014;{Evidence} for {Electrons} {Versus} {Ions}},
volume = {47},
issn = {0093-9994},
doi = {10.1109/TIA.2011.2126032},
abstract = {Whether electrons or ions are involved in triboelectric charging of insulators remains elusive. We designed polymers whose surface compositions (determined by X-ray photoelectron spectroscopy) differed from the bulk. Charging against insulators related to their topmost surface compositions, but against metals related to their bulk compositions. We propose the hypothesis that the former involves ion exchange between the topmost surfaces and the latter involves electron tunneling into the bulk, thus postulating a relationship between charging mechanism and charge penetration depth, which is supported by the fact that ions are known to adsorb to polymer surfaces and electrons are considered to penetrate into the bulk. Integration of this with the frequently conflicting evidence and hypotheses of others has, for the first time, led to a coherent though qualitative overall understanding of brief contact charging mechanisms: ion exchange for insulator-insulator contacts, both electron and ion exchange for metal-insulator contacts, and electron exchange for metal-metal contacts, consistent with successively increasing “electron availability” at these interfaces. We suggest that this concept of relative surface “availability” of the charge exchange agent also accounts for the predominance of mobile ion exchange over hydroxide ion and electron exchange when mobile-ion-containing organic salts or polymers are involved.},
number = {3},
journal = {IEEE Transactions on Industry Applications},
author = {Williams, M.W.},
month = may,
year = {2011},
keywords = {charge exchange agent, charge penetration depth, charging mechanism, electric charge, electron availability, electron exchange, electrons, electron tunneling, electron versus ion, Films, hydroxide ion, Insulators, Ions, metal-insulator contact, metal-metal contacts, Metals, Mobile communication, mobile-ion-containing organic salts, mobile ion exchange, Plastics, polymer electron, polymer insulators, polymer surface, Surface analysis of polymers, surface availability, surface charging, surface composition, triboelectric charge penetration depth, triboelectric charging, triboelectric charging mechanisms, XPS},
pages = {1093--1099},
file = {IEEE Xplore Abstract Record:/home/shakti/jarik/.mozilla/firefox/6v5y0jfw.default/zotero/storage/KN2E2AJK/abs_all.html:text/html;IEEE Xplore Full Text PDF:/home/shakti/jarik/.mozilla/firefox/6v5y0jfw.default/zotero/storage/STK8ABB9/Williams - 2011 - Triboelectric Charging of Insulators #x2014\;Eviden.pdf:application/pdf}
}
@article{kok_electrification_2009,
title = {Electrification of granular systems of identical insulators},
volume = {79},
url = {http://link.aps.org/doi/10.1103/PhysRevE.79.051304},
doi = {10.1103/PhysRevE.79.051304},
abstract = {Insulating particles can become highly electrified during powder handling, volcanic eruptions, and the wind-blown transport of dust, sand, and snow. Measurements in these granular systems have found that smaller particles generally charge negatively, while larger particles charge positively. These observations are puzzling since particles in these systems are generally chemically identical and thus have no contact potential difference. We show here that simple geometry leads to a net transfer of electrons from larger to smaller particles, in agreement with these observations. We integrate this charging mechanism into the first quantitative charging scheme for a granular system of identical insulators and show that its predictions are in agreement with measurements. Our theory thus seems to provide an explanation for the hitherto puzzling phenomenon of the size-dependent charging of granular systems of identical insulators.},
number = {5},
urldate = {2015-09-14},
journal = {Physical Review E},
author = {Kok, Jasper F. and Lacks, Daniel J.},
month = may,
year = {2009},
pages = {051304},
file = {APS Snapshot:/home/shakti/jarik/.mozilla/firefox/6v5y0jfw.default/zotero/storage/QJ25GGJF/PhysRevE.79.html:text/html}
}
@article{zhao_bipolar_2003,
title = {Bipolar charging of poly-disperse polymer powders in fluidized beds},
volume = {39},
issn = {0093-9994},
doi = {10.1109/TIA.2003.810663},
abstract = {It is well known that many common industrial powder handling operations such as pneumatic transport, mixing, and fluidization may produce a net charge on the powder particles. However, it is less well known that the net charge is often the result of a bipolar charge distribution in which the smaller particles acquire charges of a polarity opposite to those on the larger. This suggests contact charging between particles having the same chemical makeup. Very little quantitative data exist in the literature concerning this observation and no acceptable explanation currently exists. The purpose of this paper is to review the previous published work and to describe some results showing bipolar charging using polymer powders in fluidized beds. A new measurement system is described for measuring the bipolar charge distribution. This consists of a vertical array of seven Faraday pail sensors, which can selectively detect different charge components based upon particle size (gravity segregation) and charge (space-charge repulsion). For the experiments reported here the charge and mass values were measured for each sensor allowing the calculation of charge-to-mass ratio (Q/M). In addition, size distribution and surface analyses were carried out for representative samples of the powder components. Data are presented for several types of polymer powders (surface area mean diameter {\textless}100 μm). The results show that, for a given powder, even though the net charge may be positive or negative, the smaller particles show a negative charge and the coarser particles positive. These results are compared under several possible hypotheses. Each of these possibilities is examined using the measurements of the Q/M for different size fractions and the results of surface analysis and particle size distributions of these fractions.},
number = {3},
journal = {IEEE Transactions on Industry Applications},
author = {Zhao, Huiliang and Castle, G.S.P. and Inculet, I.I. and Bailey, A.G.},
month = may,
year = {2003},
keywords = {bipolar charge distribution, bipolar charging, charge measurement, charge measurement system, charge polarity, charge-to-mass ratio, Chemicals, Current measurement, electric charge, Faraday pail sensors, fluidised beds, Fluidization, fluidized beds, Gravity, gravity segregation, industrial powder handling operations, mixing, negative charge, net charge, particle size, particle size distributions, pneumatic transport, poly-disperse polymer powders, polymer powders, polymers, powders, Q measurement, Sensor arrays, Size measurement, space-charge repulsion, surface analyses, surface analysis},
pages = {612--618},
file = {IEEE Xplore Abstract Record:/home/shakti/jarik/.mozilla/firefox/6v5y0jfw.default/zotero/storage/83VPKKVQ/abs_all.html:text/html;IEEE Xplore Full Text PDF:/home/shakti/jarik/.mozilla/firefox/6v5y0jfw.default/zotero/storage/KM5ZQ6HJ/Zhao et al. - 2003 - Bipolar charging of poly-disperse polymer powders .pdf:application/pdf}
}
@article{siu_self-sustaining_2014,
title = {Self-sustaining charging of identical colliding particles},
volume = {89},
url = {http://link.aps.org/doi/10.1103/PhysRevE.89.052208},
doi = {10.1103/PhysRevE.89.052208},
abstract = {Recent experiments have demonstrated that identical material samples can charge one another after being brought into symmetric contact. The mechanism for this charging is not known. In this article, we use a simplified one-dimensional lattice model to analyze charging in the context of agitated particles. We find that the electric field from a single weakly polarized grain can feed back on itself by polarizing its neighbors, leading to an exponential growth in polarization. We show that, by incorporating partial neutralization between neighboring polarized particles, either uniform alignment of dipoles or complex charge and polarization waves can be produced. We reproduce a polarized state experimentally using identical colliding particles and raise several issues for future study.},
number = {5},
urldate = {2015-09-14},
journal = {Physical Review E},
author = {Siu, Theo and Cotton, Jake and Mattson, Gregory and Shinbrot, Troy},
month = may,
year = {2014},
pages = {052208},
file = {APS Snapshot:/home/shakti/jarik/.mozilla/firefox/6v5y0jfw.default/zotero/storage/QBM7K3M5/PhysRevE.89.html:text/html}
}
@article{hogue_calculating_2008,
title = {Calculating the trajectories of triboelectrically charged particles using {Discrete} {Element} {Modeling} ({DEM})},
volume = {66},
issn = {0304-3886},
url = {http://www.sciencedirect.com/science/article/pii/S0304388607000927},
doi = {10.1016/j.elstat.2007.08.007},
abstract = {Theoretical and experimental work has been performed pursuant to incorporating electrostatic forces into a commercial Discrete Element Modeling (DEM) software package. This DEM software is used to model the trajectories of large numbers of particles for industrial applications and processes. Electrostatic forces due to the triboelectrification of the particles will be included in the model in addition to existing kinematic forces enhancing the fidelity of the calculation. In this paper, we will present an overview of the theoretical calculations and experimental data and their comparison to the results of the DEM simulations.},
number = {1–2},
urldate = {2015-09-14},
journal = {Journal of Electrostatics},
author = {Hogue, Michael D. and Calle, Carlos I. and Weitzman, Peter S. and Curry, David R.},
month = jan,
year = {2008},
keywords = {Discrete element modeling, EDEM, Particles, Screened electrostatic force, Simulation, Triboelectric},
pages = {32--38},
file = {ScienceDirect Snapshot:/home/shakti/jarik/.mozilla/firefox/6v5y0jfw.default/zotero/storage/KCZ9AMKR/S0304388607000927.html:text/html}
}
@article{park_modeling_2002,
title = {Modeling charge transfer and induction in gas–solid fluidized beds},
volume = {55},
issn = {0304-3886},
url = {http://www.sciencedirect.com/science/article/pii/S0304388601001887},
doi = {10.1016/S0304-3886(01)00188-7},
abstract = {A simple mechanistic model is developed by applying the method of images to distinguish induced and transferred charges, assuming circular bubbles with charged particles around their surfaces. The simulation shows that the trace of induced charge vs. time is insensitive to the thickness of the layer of charged particles at the bubble surface with a uniform charge density distribution. However, charge transfer during a collision of particles surrounding the rising bubble with a probe is a strong function of the particle velocity profile. Experiments in which single bubbles were injected into an acrylic two-dimensional column showed that 321 μm glass beads, fluidized by air, were charged positively. The model with uniform charge on the surface of the bubble gives better predictions of the charge and voltage outputs than when opposite charges are assumed at the front and rear of the bubble as in previous work, but significant improvements are needed to eliminate discrepancies between the predictions and experimental measurements.},
number = {2},
urldate = {2015-09-14},
journal = {Journal of Electrostatics},
author = {Park, Ah-Hyung Alissa and Bi, Hsiaotao T. and Grace, John R. and Chen, Aihua},
month = jun,
year = {2002},
keywords = {Bubble, charge transfer, Fluidization, Model, Multiphase flow, Particle charging},
pages = {135--158},
file = {ScienceDirect Snapshot:/home/shakti/jarik/.mozilla/firefox/6v5y0jfw.default/zotero/storage/Q85MTVJM/S0304388601001887.html:text/html}
}
@article{matsusaka_triboelectric_2010,
title = {Triboelectric charging of powders: {A} review},
volume = {65},
issn = {0009-2509},
shorttitle = {Triboelectric charging of powders},
url = {http://www.sciencedirect.com/science/article/pii/S0009250910004239},
doi = {10.1016/j.ces.2010.07.005},
abstract = {Particles are often electrostatically charged by frictional contact during powder-handling operations. This phenomenon is called ‘triboelectric charging’ or ‘contact electrification’. The charged particles cause problems such as particle deposition and adhesion. In addition, if particles are excessively charged, an electrostatic discharge may occur, which can pose a risk of fire and explosion hazards; thus, to mitigate the adverse effects, it is important to elucidate the underlying triboelectric charging mechanisms. The electrostatics is, on the other hand, very useful in a number of applications that have been developed using the principles. In this review, the basic concepts and theories of charge transfer between solid surfaces are summarized, and chemical factors depending on materials and environmental effects are described. To theoretically analyze the process of particle charging, relevant models are discussed. Using the models, particle charging by repeated impacts on a wall is formulated. To experimentally evaluate particle charging, measurement and characterization methods are outlined. Furthermore, important applications and computer simulations are described.},
number = {22},
urldate = {2015-09-14},
journal = {Chemical Engineering Science},
author = {Matsusaka, S. and Maruyama, H. and Matsuyama, T. and Ghadiri, M.},
month = nov,
year = {2010},
keywords = {Characterization, charge transfer, Electrostatic application, Particulate processes, Powder technology, triboelectric charging},
pages = {5781--5807},
file = {ScienceDirect Full Text PDF:/home/shakti/jarik/.mozilla/firefox/6v5y0jfw.default/zotero/storage/V9XJZ386/Matsusaka et al. - 2010 - Triboelectric charging of powders A review.pdf:application/pdf;ScienceDirect Snapshot:/home/shakti/jarik/.mozilla/firefox/6v5y0jfw.default/zotero/storage/TWJAI3ZD/S0009250910004239.html:text/html}
}
@article{pence_effect_1994,
title = {Effect of {Surface} {Moisture} on {Contact} {Charge} of {Polymers} {Containing} {Ions}},
volume = {10},
issn = {0743-7463},
url = {http://dx.doi.org/10.1021/la00014a042},
doi = {10.1021/la00014a042},
number = {2},
urldate = {2015-09-14},
journal = {Langmuir},
author = {Pence, S. and Novotny, V. J. and Diaz, A. F.},
month = feb,
year = {1994},
pages = {592--596},
file = {ACS Full Text PDF:/home/shakti/jarik/.mozilla/firefox/6v5y0jfw.default/zotero/storage/U7E3ZV4B/Pence et al. - 1994 - Effect of Surface Moisture on Contact Charge of Po.pdf:application/pdf;ACS Full Text Snapshot:/home/shakti/jarik/.mozilla/firefox/6v5y0jfw.default/zotero/storage/A6XFXXH5/la00014a042.html:text/html}
}
@article{jalalinejad_effect_2015,
title = {Effect of electrostatics on interaction of bubble pairs in a fluidized bed},
volume = {26},
issn = {0921-8831},
url = {http://www.sciencedirect.com/science/article/pii/S0921883114002805},
doi = {10.1016/j.apt.2014.10.015},
abstract = {Electrostatic charges can influence the hydrodynamics of gas–solid fluidized beds. In our previous work (Jalalinejad et al., 2012), it was shown that high charge density modified the single bubble shape in fluidized beds. In this study, we investigate the effect of electrostatics on interaction of bubbles by simulating pairs of bubbles in vertical and horizontal alignment in uncharged and charged particles. The geometry simulated is based on the experiment of Clift and Grace (1970), with simulation results compared with their experiments for bubbles in vertical alignment. The model predicts the overall coalescence pattern, but the trailing bubble splits in simulations, unlike experiment.
The effect of electrostatics is modeled by solving electrical equations and adopting the Two Fluid Model in MFIX (an open source code). Comparison of uncharged and charged cases for bubbles in vertical alignment shows different bubble coalescence behaviour, with greater asymmetry in the charged case, leading to larger resultant bubble. For bubbles in horizontal alignment, electric charges cause the side bubble to migrate towards the axis of the column, reversing the leading-trailing role of the two bubbles, which led to the decrease in the height of complete coalescence.},
number = {1},
urldate = {2015-09-14},
journal = {Advanced Powder Technology},
author = {Jalalinejad, Farzaneh and Bi, Xiaotao T. and Grace, John R.},
month = jan,
year = {2015},
keywords = {Bubble pair, Electrostatics, Fluidization, Interaction, Two Fluid Model},
pages = {329--334},
file = {ScienceDirect Snapshot:/home/shakti/jarik/.mozilla/firefox/6v5y0jfw.default/zotero/storage/4SABT5JU/S0921883114002805.html:text/html}
}
@article{duff_particle_2008,
title = {Particle dynamics simulations of triboelectric charging in granular insulator systems},
volume = {66},
issn = {0304-3886},
url = {http://www.sciencedirect.com/science/article/pii/S0304388607000952},
doi = {10.1016/j.elstat.2007.08.005},
abstract = {Particle dynamics simulations are carried out to study triboelectric charging in granular systems composed of a single insulating material. The simulations implement a model in which electrons trapped in localized high energy states can be transferred during collisions to low energy states in the other particle. It is shown that this effect alone can generate electrostatic charging in the system, and cause net electron transfer from larger particles to smaller particles. The magnitude of charging is small for systems of a single particle size but becomes much greater for a system with polydispersal particle sizes, due to the net electron transfer from larger to smaller particles. The negative charge of smaller particles, and positive charge of larger particles has been observed in field studies and laboratory experiments of granular systems.},
number = {1–2},
urldate = {2015-09-14},
journal = {Journal of Electrostatics},
author = {Duff, Nathan and Lacks, Daniel J.},
month = jan,
year = {2008},
keywords = {Charging, Granular systems, Particle dynamics, Simulation, Triboelectrification},
pages = {51--57},
file = {ScienceDirect Snapshot:/home/shakti/jarik/.mozilla/firefox/6v5y0jfw.default/zotero/storage/27CU95D3/S0304388607000952.html:text/html}
}
@article{wiles_effects_2004,
title = {Effects of {Surface} {Modification} and {Moisture} on the {Rates} of {Charge} {Transfer} between {Metals} and {Organic} {Materials}},
volume = {108},
issn = {1520-6106},
url = {http://dx.doi.org/10.1021/jp0457904},
doi = {10.1021/jp0457904},
abstract = {This report is a study of the kinetics of contact charging resulting from the rolling of millimeter-sized metallic spheres on flat surfaces of polystyrene (PS). Charging was studied (i) for different values of the relative humidity (RH) of the air in contact with the system, (ii) in acidic and basic atmospheres, and (iii) for a series of PS surfaces oxidized to different degrees. The rates of charging increased with increasing RH; they were higher in basic atmospheres than in neutral or acidic ones and correlated with the numbers of hydrophilic groups on the surface of the polymer. These findings are consistent with a mechanism that implicates a thin film of water on the surface of PS as an important element of tribocharging in this system.},
number = {52},
urldate = {2015-09-14},
journal = {The Journal of Physical Chemistry B},
author = {Wiles, Jason A. and Fialkowski, Marcin and Radowski, Michał R. and Whitesides, George M. and Grzybowski, Bartosz A.},
month = dec,
year = {2004},
pages = {20296--20302},
file = {ACS Full Text PDF w/ Links:/home/shakti/jarik/.mozilla/firefox/6v5y0jfw.default/zotero/storage/JDCN6PGK/Wiles et al. - 2004 - Effects of Surface Modification and Moisture on th.pdf:application/pdf;ACS Full Text Snapshot:/home/shakti/jarik/.mozilla/firefox/6v5y0jfw.default/zotero/storage/JU8UQ55W/jp0457904.html:text/html}
}
@article{salaneck_double_1976,
title = {Double mass transfer during polymer‐polymer contacts},
volume = {47},
issn = {0021-8979, 1089-7550},
url = {http://scitation.aip.org/content/aip/journal/jap/47/1/10.1063/1.322306},
doi = {10.1063/1.322306},
abstract = {Double mass transfer has been observed spectroscopically and nondestructively for the first time using the x‐ray photoemission technique to examine both halves of polymer films touched to other polymer films. A careful selection of polymers according to their peculiar x‐ray photoemissionspectra enabled the unambiguous identification of polymer fragments on the respective surfaces. The use of the nondestructive XPS or ESCA technique makes possible the observations involving both halves of the contacting pair, and especially the detection of fragments of one polymer on the surface of another. The amount of material transferred is much larger than that necessary to explain triboelectric charging phenomena in terms of mass transfer on a basis of one electronic charge per atom.},
number = {1},
urldate = {2015-09-15},
journal = {Journal of Applied Physics},
author = {Salaneck, W. R. and Paton, A. and Clark, D. T.},
month = jan,
year = {1976},
keywords = {charge transfer, Mass diffusion, Photoemission, Polymer films, polymers},
pages = {144--147},
file = {Full Text PDF:/home/shakti/jarik/.mozilla/firefox/6v5y0jfw.default/zotero/storage/UU6TSKQ2/Salaneck et al. - 1976 - Double mass transfer during polymer‐polymer contac.pdf:application/pdf;Snapshot:/home/shakti/jarik/.mozilla/firefox/6v5y0jfw.default/zotero/storage/A7F7DJNK/1.html:text/html}
}
@article{jalalinejad_electro-hydrodynamics_2013,
title = {Electro-hydrodynamics of gas-solid fluidized beds},
copyright = {http://creativecommons.org/licenses/by-nc-nd/2.5/ca/},
url = {https://circle.ubc.ca/handle/2429/45136},
abstract = {The generation of electrical charges, reported in gas-solid fluidized beds for over sixty years, can cause serious problems like wall sheeting in polyolefin reactors, leading to costly shutdown, electrical shock hazards and even explosions. Understanding the associated phenomena plays an important role to avoid these problems. In this study an attempt has been made to broaden the understanding of electrostatics in fluidized beds by adopting computational fluid dynamics (CFD), using the Two-Fluid-Model in MFIX (an open-source code originated by the U.S. Department of Energy). The Maxwell equations were incorporated in the MFIX code. The resulting model is then used to investigate how electrostatics modify bubble shape, size, velocity and interaction for three cases: (a) single bubbles, (b) bubble pairs in vertical and horizontal alignment, and (c) a freely-bubbling bed. In each of these cases, a two-dimensional column, partially filled with mono-sized particles, is simulated for both uncharged and charged particles.
In case (a), it is predicted that single bubbles elongate and rise more quickly in charged particles than in uncharged ones. For case (b), electrostatics cause asymmetry of coalescence for a pair of vertically-aligned bubbles, while leading to the migration of a side bubble towards the axis of the column and changing the leading-trailing role for a pair of horizontally-aligned bubbles. Finally in case (c), the simulation predicts that electrostatics decrease bubble size and frequency in the free bubbling regime, accompanied by a change in the spatial distribution of bubbles, causing them to rise more towards the axis of the column.
An attempt was also made to test experimentally the single bubble simulations. To reach this goal, a two-dimensional fluidization column was built with a central jet to inject single bubbles. The setup is equipped with a novel Faraday-cup device to measure the charge density accurately. The experimental results indicates a small decrease in bubble size and an increase in bubble height-to-width ratio with increasing charge density, accompanied by an increase in particles raining from the bubble roof. The assumption of uniform charge density on the particles is identified as a significant reason for differences between observed and predicted behaviour.},
language = {eng},
urldate = {2015-09-14},
author = {Jalalinejad, Farzaneh},
year = {2013},
file = {Full Text PDF:/home/shakti/jarik/.mozilla/firefox/6v5y0jfw.default/zotero/storage/UGAWWK5Q/Jalalinejad - 2013 - Electro-hydrodynamics of gas-solid fluidized beds.pdf:application/pdf;Snapshot:/home/shakti/jarik/.mozilla/firefox/6v5y0jfw.default/zotero/storage/HWTP6EK6/45136.html:text/html}
}
@article{shinbrot_granular_2008,
title = {Granular matter: {Static} in motion},
volume = {451},
copyright = {© 2008 Nature Publishing Group},
issn = {0028-0836},
shorttitle = {Granular matter},
url = {http://www.nature.com/nature/journal/v451/n7180/full/451773a.html},
doi = {10.1038/451773a},
abstract = {Wind-blown desert sands can charge up spontaneously. But although sand flow and the forces on charged bodies are well studied separately, surprisingly little is known of what happens when the two combine.},
language = {en},
number = {7180},
urldate = {2015-09-15},
journal = {Nature},
author = {Shinbrot, Troy and Herrmann, Hans J.},
month = feb,
year = {2008},
pages = {773--774},
file = {Full Text PDF:/home/shakti/jarik/.mozilla/firefox/6v5y0jfw.default/zotero/storage/H3CWPE5Q/Shinbrot and Herrmann - 2008 - Granular matter Static in motion.pdf:application/pdf;Snapshot:/home/shakti/jarik/.mozilla/firefox/6v5y0jfw.default/zotero/storage/AIX8MTFQ/451773a.html:text/html}
}
@article{forward_charge_2009,
title = {Charge {Segregation} {Depends} on {Particle} {Size} in {Triboelectrically} {Charged} {Granular} {Materials}},
volume = {102},
url = {http://link.aps.org/doi/10.1103/PhysRevLett.102.028001},
doi = {10.1103/PhysRevLett.102.028001},
abstract = {Experiments are carried out to examine triboelectric charging in granular systems composed of particles that are chemically identical but differ in size. A methodology is developed so that only particle-particle interactions (but not particle-wall interactions) contribute to the charging. Since all particles are chemically identical, there is no apparent driving force for charge transfer, but charging occurs nonetheless, such that smaller particles tend to charge negatively while larger particles tend to charge positively. For bimodal systems, a model for the frequency of collisions of particles with different size predicts the concentrations for which the observed charge segregation is maximized.},
number = {2},
urldate = {2015-09-14},
journal = {Physical Review Letters},
author = {Forward, Keith M. and Lacks, Daniel J. and Sankaran, R. Mohan},
month = jan,
year = {2009},
pages = {028001},
file = {APS Snapshot:/home/shakti/jarik/.mozilla/firefox/6v5y0jfw.default/zotero/storage/SNAJ48QK/PhysRevLett.102.html:text/html}
}
@article{mccarty_electrostatic_2008,
title = {Electrostatic {Charging} {Due} to {Separation} of {Ions} at {Interfaces}: {Contact} {Electrification} of {Ionic} {Electrets}},
volume = {47},
copyright = {Copyright © 2008 WILEY-VCH Verlag GmbH \& Co. KGaA, Weinheim},
issn = {1521-3773},
shorttitle = {Electrostatic {Charging} {Due} to {Separation} of {Ions} at {Interfaces}},
url = {http://onlinelibrary.wiley.com/doi/10.1002/anie.200701812/abstract},
doi = {10.1002/anie.200701812},
abstract = {This Review discusses ionic electrets: their preparation, their mechanisms of formation, tools for their characterization, and their applications. An electret is a material that has a permanent, macroscopic electric field at its surface; this field can arise from a net orientation of polar groups in the material, or from a net, macroscopic electrostatic charge on the material. An ionic electret is a material that has a net electrostatic charge due to a difference in the number of cationic and anionic charges in the material. Any material that has ions at its surface, or accessible in its interior, has the potential to become an ionic electret. When such a material is brought into contact with some other material, ions can transfer between them. If the anions and cations have different propensities to transfer, the unequal transfer of these ions can result in a net transfer of charge between the two materials. This Review focuses on the experimental evidence and theoretical models for the formation of ionic electrets through this ion-transfer mechanism, and proposes—as a still-unproved hypothesis—that this ion-transfer mechanism may also explain the ubiquitous contact electrification (“static electricity”) of materials, such as organic polymers, that do not explicitly have ions at their surface.},
language = {en},
number = {12},
urldate = {2015-09-14},
journal = {Angewandte Chemie International Edition},
author = {McCarty, Logan S. and Whitesides, George M.},
month = mar,
year = {2008},
keywords = {charge transfer, electron transfer, electrostatic interactions, interfaces, polymers},
pages = {2188--2207},
file = {Full Text PDF:/home/shakti/jarik/.mozilla/firefox/6v5y0jfw.default/zotero/storage/PW5DKG5D/McCarty and Whitesides - 2008 - Electrostatic Charging Due to Separation of Ions a.pdf:application/pdf;Snapshot:/home/shakti/jarik/.mozilla/firefox/6v5y0jfw.default/zotero/storage/KKTQ8CDV/full.html:text/html}
}
@article{pahtz_why_2010,
title = {Why do particle clouds generate electric charges?},
volume = {6},
copyright = {© 2010 Nature Publishing Group},
issn = {1745-2473},
url = {http://www.nature.com/nphys/journal/v6/n5/abs/nphys1631.html},
doi = {10.1038/nphys1631},
abstract = {Grains in desert sandstorms spontaneously generate strong electrical charges; likewise volcanic dust plumes produce spectacular lightning displays. Charged particle clouds also cause devastating explosions in food, drug and coal processing industries. Despite the wide-ranging importance of granular charging in both nature and industry, even the simplest aspects of its causes remain elusive, because it is difficult to understand how inert grains in contact with little more than other inert grains can generate the large charges observed. Here, we present a simple yet predictive explanation for the charging of granular materials in collisional flows. We argue from very basic considerations that charge transfer can be expected in collisions of identical dielectric grains in the presence of an electric field, and we confirm the model’s predictions using discrete-element simulations and a tabletop granular experiment.},
language = {en},
number = {5},
urldate = {2015-09-14},
journal = {Nature Physics},
author = {Pähtz, T. and Herrmann, H. J. and Shinbrot, T.},
month = may,
year = {2010},
pages = {364--368},
file = {Full Text PDF:/home/shakti/jarik/.mozilla/firefox/6v5y0jfw.default/zotero/storage/QVVKHC5Q/Pähtz et al. - 2010 - Why do particle clouds generate electric charges.pdf:application/pdf;Snapshot:/home/shakti/jarik/.mozilla/firefox/6v5y0jfw.default/zotero/storage/BXP2T89B/nphys1631.html:text/html}
}
@article{sowinski_investigation_2010,
title = {Investigation of electrostatic charge distribution in gas–solid fluidized beds},
volume = {65},
issn = {0009-2509},
url = {http://www.sciencedirect.com/science/article/pii/S0009250910000175},
doi = {10.1016/j.ces.2010.01.008},
abstract = {Over the past few decades there have been numerous attempts to measure electrostatic charges in gas–solid fluidized bed reactors; these charges have been prone to cause reactor downtime from electrostatic phenomena. In this study, a new system was developed that aimed to quantifying the electrostatic charge generation in three key areas within a gas–solid fluidized bed simultaneously: the bed particles, the particles that adhered to the column wall, and the particles that were entrained from the column. A unique online Faraday cup method was used to measure the electrostatic charge of the particles. The system was operated with dry air at two fluidizing gas velocities, one in the bubbling and the other in the slugging flow regime. An industrial polyethylene resin with a wide particle size range was utilized in all experiments. Results showed the occurrence of bi-polar charging in both flow regimes with entrained fines being mainly positively charged, whereas the bed particles and those attached to the column wall carrying a net negative charge. The charge-to-mass ratio (q/m) of the entrained fines in the bubbling regime was significantly higher than in the slugging regime. It was discovered that particles with a certain size range were predominantly adhering to the column wall with a significantly higher q/m than the other bed particles. These findings led to a proposed mechanism for the migration of particles within the fluidization column due to the effect of electrostatic charge generation.},
number = {9},
urldate = {2015-09-14},
journal = {Chemical Engineering Science},
author = {Sowinski, Andrew and Miller, Leigh and Mehrani, Poupak},
month = may,
year = {2010},
keywords = {Electrostatics, Faraday cup, Gas–solid fluidization, Particle charging, Polymerization},
pages = {2771--2781},
file = {ScienceDirect Full Text PDF:/home/shakti/jarik/.mozilla/firefox/6v5y0jfw.default/zotero/storage/UVQPCWME/Sowinski et al. - 2010 - Investigation of electrostatic charge distribution.pdf:application/pdf;ScienceDirect Snapshot:/home/shakti/jarik/.mozilla/firefox/6v5y0jfw.default/zotero/storage/FZRUFQH3/S0009250910000175.html:text/html}
}
@inproceedings{laurentie_numerical_2010,
title = {Numerical {Modeling} of {Triboelectric} {Charging} of {Granular} {Materials} in {Vibrated} {Beds}},
doi = {10.1109/IAS.2010.5615669},
abstract = {The triboelectric charging of granular materials is a complex physical phenomenon, the outcome of which is difficult to predict. The aim of this paper is to validate a numerical model of the tribocharging process taking place in vertically-vibrated beds of granular plastics. The granular dynamics is modeled with the Distinct Element Method that is commonly employed to design pneumatic conveyors or predict hopper emptying. The charge exchanged in granule-to-granule and granule-to-wall collisions is computed by taking into account the physical properties of the respective materials, their area of contact, as well as the effect of the electric field created by a system of high-voltage electrodes and by the charges of the granules themselves. The numerical model simulates also the free-fall motion of the charged granules in the electrostatic field created between two vertical plate electrodes. The outcome of the simulation, i.e. the charge of the particles collected at the two electrodes in a definite laps of time, is in good agreement with the results of an experiment carried out with mixtures of mm-size polyamide and polycarbonate granules in a laboratory vibrated bed.},
booktitle = {2010 {IEEE} {Industry} {Applications} {Society} {Annual} {Meeting} ({IAS})},
author = {Laurentie, J.-C. and Traoré, P. and Dragan, C. and Dascalescu, L.},
month = oct,
year = {2010},
keywords = {Atmospheric modeling, Computational modeling, distinct element method, Electric fields, electrostatic field, Electrostatics, Force, free-fall motion, granular dynamics, granular materials, granular plastics, granule-to-granule collisions, granule-to-wall collisions, high-voltage electrodes, hopper emptying, Materials, mm-size polyamide, numerical analysis, numerical modeling, Numerical models, Plastics, pneumatic conveyors, polycarbonate granules, tribocharging process, triboelectric charging, triboelectricity, vertically-vibrated beds},
pages = {1--6},
file = {IEEE Xplore Abstract Record:/home/shakti/jarik/.mozilla/firefox/6v5y0jfw.default/zotero/storage/GX6TGQ2A/abs_all.html:text/html;IEEE Xplore Full Text PDF:/home/shakti/jarik/.mozilla/firefox/6v5y0jfw.default/zotero/storage/IU4M7M6X/Laurentie et al. - 2010 - Numerical Modeling of Triboelectric Charging of Gr.pdf:application/pdf}
}
@article{jalalinejad_effect_2012,
title = {Effect of electrostatic charges on single bubble in gas–solid fluidized beds},
volume = {44},
issn = {0301-9322},
url = {http://www.sciencedirect.com/science/article/pii/S030193221200050X},
doi = {10.1016/j.ijmultiphaseflow.2012.03.008},
abstract = {Electrostatic charges are well known to influence the hydrodynamics of gas–solid fluidized beds, but no detailed description is currently available showing how they can influence bubble properties such as shape and velocity. This study simulates the injection of single bubbles into a fluidized bed of charged particles. The effect of electrostatic charge is modeled by the Two Fluid Model (TFM) implemented in MFIX code, solving the governing momentum, continuity and electrical equations. This model is initially evaluated for an uncharged system by comparing the numerical predictions with the bubble shape measured by Gidaspow D., Seo, Y., Ettehadieh, B. [1983. Hydrodynamics of fluidization: Experimental and theoretical bubble sizes in a two dimensional bed with jet. Chem. Eng. Commun. 22, 253–272] and particle pressures measured by Rahman, K., Campbell, C. [2002. Particle pressures generated around bubbles in gas fluidized beds. J. Fluid Mech. 455, 103–127]. The effect of charged particles on bubble behavior is then simulated. The simulations show bubble elongation in the flow direction. As a result, bubbles rise more quickly than for the uncharged case. Analysis is performed on the magnitude of charge density and the choice of frictional model. The bubble deformation is explained based on forces on particles at the bubble periphery.},
urldate = {2015-09-14},
journal = {International Journal of Multiphase Flow},
author = {Jalalinejad, Farzaneh and Bi, Xiaotao T. and Grace, John R.},
month = sep,
year = {2012},
keywords = {Bubble, Electrostatics, Gas–solid fluidized bed, Two Fluid Model},
pages = {15--28},
file = {ScienceDirect Snapshot:/home/shakti/jarik/.mozilla/firefox/6v5y0jfw.default/zotero/storage/MJK6UGAE/S030193221200050X.html:text/html}
}
@phdthesis{harper_1967,
author = "W.R. Harper",
title = "Contact and Frictional Electrification",
school = "Oxford",
year = "1967"
}
@book{jones_king_1991,
author = "Thomas B. Jones and Jack L. King",
title = "Powder Handling and Electrostatics",
publisher = "Lewis Publishers Inc.",
year = "1991",
}
