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Relevant bibliographies by topics / Electrostic barriers

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Academic literature on the topic 'Electrostic barriers'

Author: Grafiati

Published: 4 June 2021

Last updated: 14 February 2022

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Journal articles on the topic "Electrostic barriers"

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Lee, Myungjin, Chen Bai, Mikolaj Feliks, Raphael Alhadeff, and Arieh Warshel. "On the control of the proton current in the voltage-gated proton channel Hv1." Proceedings of the National Academy of Sciences 115, no. 41 (September 25, 2018): 10321–26. http://dx.doi.org/10.1073/pnas.1809766115.

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The nature of the action of voltage-activated proton transport proteins is a conundrum of great current interest. Here we approach this issue by exploring the action of Hv1, a voltage-gated proton channel found in different cells in humans and other organisms. Our study focuses on evaluating the free energy of transporting a proton through the channel, as well as the effect of the proton transfer through D112, in both the closed and open channel conformations. It is found that D112 allows a transported proton to bypass the electrostatic barrier of the open channel, while not being able to help in passing the barrier in the closed form. This reflects the change in position of the gating arginine residues relative to D112, upon voltage activation. Significantly, the effect of D112 accounts for the observed trend in selectivity by overcoming the electrostatic barrier at its highest point. Thus, the calculations provide a structure/function correlation for the Hv1 system. The present work also clarifies that the action of Hv1 is not controlled by a Grotthuss mechanism but, as is always the case, by the protein electrostatic potential at the rate-limiting barriers.

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Schaefer, Ted, Craig S. Takeuchi, Guy M. Bernard, and Frank E. Hruska. "Theoretical and experimental barriers to internal rotation in 2,6-difluorobenzaldehyde and 2,4,6-trifluorobenzaldehyde. Relatively low barriers." Canadian Journal of Chemistry 73, no. 1 (January 1, 1995): 106–12. http://dx.doi.org/10.1139/v95-016.

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The free energies of activation at 110 K for rotation about the exocyclic C—C bonds in 2,6-difluorobenzaldehyde and 2,4,6-trifluorobenzaldehyde, in dimethyl ether solutions, are 18.8 ± 0.5 and 20.0 ± 0.5 kJ mol−1, respectively, as determined from 19F{1H} dynamic nuclear magnetic resonance measurements. For the parent compound ΔG≠ is 32.2 kJ mol−1 in the same solvent. These free energy barriers, the lowest available for benzaldehyde derivatives, are likely a result of steric and electrostatic repulsions between the C+—O− and C+—F− bonds. Computations of the spectroscopic barrier in the 2,6-difluoro compound at various levels of molecular orbital theory imply that the barrier is predominantly twofold, with a fourfold component of opposite sign, whose magnitude is about 10% of the twofold component. A correlation-gradient computation, MP2/6-31G*, finds a barrier height of 18.6 kJ mol−1 for this compound, lower by 3.0 kJ mol−1 than found with the 6-31G* basis and 2.9 kJ mol−1 with 6-31G**. Similar computations are compared for the parent compound and the 4-fluoro, 2,4,6-trifluoro, and 3,5-difluoro derivatives. Linear relationships exist between the computed spectroscopic barriers (ΔE values at absolute zero for the free molecules) and the free energy barriers for benzaldehyde and the four fluoro derivatives; the theoretical barriers utilize 6-31G** and correlation-gradient MP2/6-31G* procedures. For the 2,6-difluoro derivative, the computed frequencies of the torsional motions about the exocyclic C—C bond yield spectroscopic twofold barriers. These barriers are much lower than the computed energy differences between the planar and perpendicular conformers, perhaps because the negative fourfold components flatten the potential at its minimum. A rough estimate of the relationship between ΔG≠ and ΔE0 for the 2,6-difluorobenzaldehyde suggests that the solvent increases the internal barrier by only about 3 kJ mol−1. By way of contrast, the AM1 barriers, scaled by a factor of 1.9 (as previously recommended) range from 17.3 to 22.6 kJ mol−1, the ΔG≠ values from 18.8(5) to 34.4 kJ mol−1, and the MP2/6-31G* (correlation-gradient) barriers span 18.6 to 36.8 kJ mol−1 for benzaldehyde and the four fluorine derivatives. It seems likely that the internal barrier in benzaldehyde is considerably larger than that modeled on torsional frequencies. Keywords: Free energies of activation, internal rotational barriers in 2,6-difluoro- and 2,4,6-trifluorobenzaldehyde; molecular orbital computations, internal rotational barriers in 2,6-difluoro- and 2,4,6-trifluorobenzaldehyde; correlation gradient computations on internal barriers in benzaldehyde and four of its fluorine derivatives.

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Li, Hao, Yan-Li Zhao, Albert C. Fahrenbach, Soo-Young Kim, Walter F. Paxton, and J. Fraser Stoddart. "Degenerate [2]rotaxanes with electrostatic barriers." Organic & Biomolecular Chemistry 9, no. 7 (2011): 2240. http://dx.doi.org/10.1039/c0ob00937g.

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Hmadeh, Mohamad, Albert C. Fahrenbach, Subhadeep Basu, Ali Trabolsi, Diego Benítez, Hao Li, Anne‐Marie Albrecht‐Gary, Mourad Elhabiri, and J. Fraser Stoddart. "Electrostatic Barriers in Rotaxanes and Pseudorotaxanes." Chemistry – A European Journal 17, no. 22 (April 15, 2011): 6076–87. http://dx.doi.org/10.1002/chem.201002933.

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Zhou, Xuechen, Zhangxin Wang, Razi Epsztein, Cheng Zhan, Wenlu Li, John D. Fortner, Tuan Anh Pham, Jae-Hong Kim, and Menachem Elimelech. "Intrapore energy barriers govern ion transport and selectivity of desalination membranes." Science Advances 6, no. 48 (November 2020): eabd9045. http://dx.doi.org/10.1126/sciadv.abd9045.

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State-of-the-art desalination membranes exhibit high water-salt selectivity, but their ability to discriminate between ions is limited. Elucidating the fundamental mechanisms underlying ion transport and selectivity in subnanometer pores is therefore imperative for the development of ion-selective membranes. Here, we compare the overall energy barrier for salt transport and energy barriers for individual ion transport, showing that cations and anions traverse the membrane pore in an independent manner. Supported by density functional theory simulations, we demonstrate that electrostatic interactions between permeating counterion and fixed charges on the membrane substantially hinder intrapore diffusion. Furthermore, using quartz crystal microbalance, we break down the contributions of partitioning at the pore mouth and intrapore diffusion to the overall energy barrier for salt transport. Overall, our results indicate that intrapore diffusion governs salt transport through subnanometer pores due to ion-pore wall interactions, providing the scientific base for the design of membranes with high ion-ion selectivity.

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COMA, V., I. SEBTI, P. PARDON, A. DESCHAMPS, and F. H. PICHAVANT. "Antimicrobial Edible Packaging Based on Cellulosic Ethers, Fatty Acids, and Nisin Incorporation To Inhibit Listeria innocua and Staphylococcus aureus." Journal of Food Protection 64, no. 4 (April 1, 2001): 470–75. http://dx.doi.org/10.4315/0362-028x-64.4.470.

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Edible cellulosic films made with hydroxypropylmethylcellulose (HPMC) have proven to be inadequate moisture barriers. To improve its water vapor barrier properties, different hydrophobic compounds were incorporated into the HPMC matrix. Some fatty acids and derivatives were included into the film-forming solution prior to film formation. Stearic acid was chosen because of its high capacity to reduce significantly the water vapor transmission rate. Antimicrobial activity of edible HPMC film was obtained by the incorporation of nisin into the film-forming solution. Nisin is an antimicrobial peptide effective against gram-positive bacteria. The inhibitory activity of this bacteriocin was tested for inhibition of Listeria innocua and Staphylococcus aureus. The use of stearic acid was observed to reduce the inhibitory activity of active HPMC film against both selected strains. This phenomenon may be explained by electrostatic interactions between the cationic nisin and the anionic stearic acid. Further studies showed that antimicrobial activity of film varied with the nature of the hydrophobic compound incorporated, in decreasing order: film without lipid, methylstearate film, and stearic acid film. This corroborated the idea of electrostatic interactions.

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AGRAWAL (GARG), NEETU, SANKALPA GHOSH, and MANISH SHARMA. "ELECTRON OPTICS WITH DIRAC FERMIONS: ELECTRON TRANSPORT IN MONOLAYER AND BILAYER GRAPHENE THROUGH MAGNETIC BARRIER AND THEIR SUPERLATTICES." International Journal of Modern Physics B 27, no. 10 (April 20, 2013): 1341003. http://dx.doi.org/10.1142/s0217979213410038.

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In this review article we discuss the recent progress in studying ballistic transport for charge carriers in graphene through highly inhomogeneous magnetic field known as magnetic barrier in combination with gate voltage induced electrostatic potential. Starting with cases for a single or double magnetic barrier we also review the progress in understanding electron transport through the superlattices created out of such electromagnetic potential barriers and discuss the possibility of experimental realization of such systems. The emphasis is particularly on the analogy of such transport with propagation of light wave through medium with alternating dielectric constant. In that direction we discuss electron analogue of optical phenomena like Fabry–Perot resonances, negative refraction, Goos–Hänchen effect, beam collimation in such systems and explain how such analogy is going to be useful for device generation. The resulting modification of band structure of Dirac fermions, the emergence of additional Dirac points was also discussed accompanied by brief section on the interconvertibility of electric and magnetic field for relativistic Dirac fermions. We also discuss the effect of such electromagnetic potential barrier on bilayer graphene (BLG) in a similar framework.

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Chung, Suk, Shane R. Johnson, Ding Ding, Yong-Hang Zhang, David J. Smith, and Martha R. McCartney. "Quantitative Analysis of Dopant Distribution and Activation Across p-n Junctions in AlGaAs/GaAs Light-Emitting Diodes Using Off-Axis Electron Holography." IEEE Transactions on Electron Devices 56, no. 10 (September 2009): 1919–23. http://dx.doi.org/10.1109/ted.2009.2025914.

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Off-axis electron holography has been used to measure the electrostatic potential profile across the p-n junction of an AlGaAs/GaAs light-emitting diode with linearly graded triangular AlGaAs barriers. Simulations of the junction profile showed small discrepancies with experiment when the nominal dopant concentrations of Si and Be impurities were used. Revised simulations reproduced the measurements reasonably using reduced dopant levels that reflected the efficiency of dopant activation. Band-edge diagrams simulated with the nominal and revised dopant concentrations were also compared in terms of the effect that activation efficiency had on the AlGaAs barrier shape and carrier transport. It is concluded that electron holography measurements combined with modeling offer device designers and growers a helpful tool for analyzing and confirming doping profiles in complex heterostructures.

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Choubabi, El Bouâzzaoui, Ahmed Jellal, Abdellatif Kamal, and Hocine Bahlouli. "Tunneling through Double Electrostatic Barriers in Strained Graphene." physica status solidi (b) 257, no. 3 (November 28, 2019): 1900414. http://dx.doi.org/10.1002/pssb.201900414.

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Kane, C. L., and E. J. Mele. "Dielectric control of electrostatic barriers for molecular electronics." Applied Physics Letters 78, no. 1 (January 2001): 114–16. http://dx.doi.org/10.1063/1.1336162.

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Dissertations / Theses on the topic "Electrostic barriers"

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Heide, Carsten. "Nonequilibrium processes in heterostructures under the influence of internal and external magnetic fields." Thesis, University of Oxford, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.389021.

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Forsberg, Björn. "Classical over-the-barrier model for ionization of poly-cyclic aromatic hydrocarbons in keV-collisions with atomic ions." Thesis, Stockholms universitet, Fysikum, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-60168.

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We are developing a novel classical over-the barrier model for electron transfer from an in nitely thin conducting disc to a point charge projectile to model multiple electron capture in e.g. keV collisions of atomic ions with poly-cyclic aromatic hydrocarbons (PAHs). In its nal form, the present model will incorporate the polarization of the PAH molecules due to the active electron and the point charge projectile at a general angle of incidence. This will drastically improve the description of the potential barrier in comparisons with simpler versions of the model where the nite size and polarizability of the target molecule is neglected or treated in an averaged fashion. In this work we arrive at expressions for the electrostatic potential energy barrier experienced by the active electron in the two spatial orientations where the point charge projectile is located along the normal symmetry axis and in the tangent plane of the disc. Applied to coronene (C24H12) such barriers compare better with high level density functional theory (DFT) calculations than with the results from the simpler versions of the classical over-the-barrier models for atomic and spherical cluster targets. These results thus strongly supports the conducting disc approximation of PAHs. Finally we discuss the nal steps in the model development and possible extensions of the model to include less symmetric elliptical discs or spherical caps.

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Gouri, Rabah. "Optimisation électrique et géométrique d'un électrofiltre à barrière diélectrique en configuration fil-tube carré. Application aux particules submicroniques." Thesis, Poitiers, 2012. http://www.theses.fr/2012POIT2279/document.

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L'objectif de ce travail est l'étude de l'efficacité de collecte des particules submicroniques d'un électrofiltre deconfiguration fil-tube carré en utilisant une Décharge à Barrière Diélectrique (DBD). Les expériences sont faites avec desparticules de fumée d'encens ayant une taille moyenne d'environ 0,32 pm. La répartition en taille des particules à la sortie del'électrofiltre est mesurée grâce à un spectromètre d'aérosols à lumière blanche. L'efficacité de collecte est estimé pour diversestensions et fréquences appliquées (gammes : 4-30 kV, de 0,3 à 1000 Hz) à un débit d'air fixe.Le premier volet de l'analyse a consisté en une caractérisation électrique et granulomètrique de l'électrofiltre de configurationcarré dit de référence. Les résultats obtenus ont montré que le comportement électrique de l'électrofiltre de géométrie carré estsimilaire à celui de géométrie cylindrique. Aussi, l'utilisation de la DBD pour la précipitation donnait de très bons résultats enconfiguration fil-tube carré (plus de 99% d’efficacité). Le second volet de notre étude a été consacré à l'optimisation géométrique de l'électrofiltre de référence. Les résultats ont montré que le diamètre du fil, le nombre des faces collectrices ont une influence minime sur la précipitation. Tandis que, la section du tube et la largeur de la contre électrode et sa discrétisation ont une influence importante. L'analyse de l'effet de la présence d'une deuxième Barrière Diélectrique (BD) a montré qu'à la différence de la simple BD ou le mode de décharge est assez homogène, la décharge a un comportement filamentaire dans le cas de la double BD. Aussi, l'efficacité de collecte des particules pour les deux con
The objective of this work is the study of the collection efficiency of submicron particles with wire-to-square tubeElectroStatic Precipitator (ESP) using a Dielectric Barrier Discharge (DBD). The experiments are performed with incense smokeparticles having a mean size of about 0.32 μm. An aerosol spectrometer is employed for characterizing the size distribution ofthese particles at the outlet of the ESPs. The collection efficiency is estimated for various applied voltages and frequencies(ranges: 4–30 kV, 0.3–1000 Hz) at a fixed air flow rate.The first step of our study consisted of an electrical characterization of the reference precipitator and the evaluation of itscollection efficiency performances. The results have shown that electrical behavior of the wire-to-square tube configuration issimilar to the wire-to- cylinder configuration. Furthermore, it reveals that the square configuration charged with a DBD gives verygood results (more than 99% of efficiency). The second step of the study was devoted to the geometrical optimization of thesquare ESP. The obtained results have established that the wire diameter, the number of faces has a minimal effect on electrostatic precipitation. However, the tube section, the width of the ground electrode and its discretization have an important effect. Also, the analysis of the effect of the presence of a second Dielectric Barrier (DB) has shown that in the case of the single DB, the discharge mode is rather homogeneous. In contrast, the discharge has a filamentary behavior in the case of the double DB. Results show that the particle collection efficiency of both ESPs is higher at high applied voltages and within a certai

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Okuzumi, Satoshi. "Theoretical Modeling of the Charging and Structure Evolution of Dust Aggregates in Protoplanetary Disks : Possible Discovery of an Electrostatic Barrier Against Dust Growth." Kyoto University, 2010. http://hdl.handle.net/2433/120430.

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Kyoto University (京都大学)
0048
新制・課程博士
博士(人間・環境学)
甲第15464号
人博第494号
新制||人||121(附属図書館)
21||人博||494(吉田南総合図書館)
27942
京都大学大学院人間・環境学研究科相関環境学専攻
(主査)教授阪上雅昭, 准教授小木曽哲, 准教授木下俊哉, 助教野村英子
学位規則第4条第1項該当

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Richard, Gontran. "Étude expérimentale et optimisation fonctionnelle des installations de séparation électrostatique de mélanges de matériaux granulaires." Thesis, Poitiers, 2018. http://www.theses.fr/2018POIT2260/document.

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La démarche expérimentale menée dans cette thèse CIFRE a eu comme objectif l’étude de la faisabilité de la séparation électrostatique d’une large gamme de mélanges de matériaux granulaires issus de déchets d’équipements électriques et électroniques (conducteur – isolant, conducteur – conducteur et isolant – isolant). Trois mécanismes physiques de charge électriques ont été mis en oeuvre : l’induction électrostatique, la décharge couronne et l’effet triboélectrique. Un dispositif de charge de laboratoire et deux séparateurs électrostatiques industriels ont été conçus et réalisés. Le dispositif de charge à cylindre(s) tournant(s) permet la charge triboélectrique de matériaux plastiques. Le prototype de séparateur industriel a d’abord été réalisé pour le traitement de mélanges granulaires conducteur – isolant puis a été adapté à la séparation isolant – isolant. Les trois mécanismes de charge peuvent y être utilisés. Ce prototype a permis la fabrication du premier séparateur électrostatique de série de la société CITF dédié à la séparation de déchets de câbles électriques. Des mesures de charge et de masse ainsi que des simulations et visualisations des trajectoires des particules par caméra rapide ont facilité l’analyse des phénomènes. La méthode des plans d’expérience a permis d’identifier les facteurs influents sur les processus de séparation et de définir leur point de fonctionnement optimal. L’influence d’une décharge à barrière diélectrique sur la charge triboélectrique et la séparation électrostatique de mélanges plastiques a été étudiée. Les travaux réalisés dans cette thèse ont confirmé la séparabilité électrostatique de mélanges de matériaux granulaires
The experimental approach used in this thesis was aimed at the study of the feasibility of the electrostatic separation of a wide range of granular mixtures from waste electric and electronic equipment (conductive – insulator, conductive – conductive, insulator – insulator). Three physical mechanisms of electrical charging have been employed: electrostatic induction, corona discharge and triboelectric effect. A tribocharging device and two industrial electrostatic separators have been designed and engineered. The rotating cylinder tribocharging device allows the triboelectric charging of plastics. The industrial separator prototype was firstly built for processing conducting – insulator granular mixtures and then adapted for insulator – insulator separation. This prototype, which enables the use of all three electrical charging mechanisms, served as model for the CITF company first industrial electrostatic separator for the recycling of metals and plastics from electric cable wastes. Charge and mass measurement, as well as modelling and visualization of particle trajectories by a high-speed camera facilitated the investigations. Design of experiments method was used to define the influential factors and find the optimum operating conditions of the separation processes. Dielectric barrier discharge exposure of granular plastics may enhance the efficiency of the triboelectric charging of these materials and hence facilitate their electrostatic separation. These researches have confirmed the feasibility of the electrostatic separation of a wide variety of granular mixtures

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Aba'a, Ndong Arthur. "Décharges à barrière diélectrique pulsées de volume et de surface appliquées à la précipitation électrostatique et à la régénération de surface." Thesis, Poitiers, 2014. http://www.theses.fr/2014POIT2322/document.

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Dans le cadre de cette thèse, des Décharges à Barrières Diélectrique (DBD) pulsées de volume et de surface ont été étudiées expérimentalement, dans le but de les appliquer respectivement à la précipitation électrostatique de particules submicroniques et à la régénération de surface.La caractérisation des DBD pulsées a consisté à effectuer des mesures électriques (courant, énergie) et optiques (imagerie ICCD), afin d'observer l'influence des paramètres électriques et géométriques, ainsi que des matériaux utilisés, sur les propriétés de la décharge. Il en ressort que pour les deux types de DBD (surface et volume), le courant présente deux pics durant les fronts montant et descendant du pulse de tension, et que les deux décharges ont des aspects différents (filamentaire ou diffus).Concernant la précipitation électrostatique, l'efficacité de collecte des électrofiltres a été déterminée par des mesures granulométriques. Les résultats montrent que celle-ci est influencée par les paramètres électriques et géométriques des électrofiltres. Une caractérisation des phénomènes EHD au sein des électrofiltres par métrologie optique (LDV et PIV) a été effectuée afin de comprendre les mécanismes de charge et de dérive des particules.Ensuite, la régénération de surface a été étudiée en analysant les images de la surface polluée, avant et après le traitement. Les résultats révèlent que les performances de la régénération sont influencées par les paramètres électriques, géométriques et les matériaux des réacteurs DBD. Les mécanismes de la régénération ont été analysés en relevant l'évolution de la taille et la concentration des particules générées lors du processus de régénération
As part of this thesis, volume and surface pulsed Dielectric Barrier Discharges (DBD) were investigated experimentally for applications in the electrostatic precipitation of submicron particles and surface regeneration, respectively. First, the characterization of pulsed DBDs consisted of performing electrical measurements (current, power) and optical measurements (ICCD imaging) in order to observe the influence of electrical and geometrical parameters as well as materials on the properties of the discharge. It is demonstrated that for both types of DBD (surface and volume), the current has two peaks during the rising and falling times of the voltage pulse, corresponding to distinct streamer and glow discharge regimes, respectively.Next, the collection efficiency of electrostatic precipitation (ESP) was determined by granulometric measurements. The results show that the efficiency is influenced by the electrical and geometrical parameters of the precipitator. A characterization of EFD phenomena was performed inside the precipitator by optical metrology (LDV and PIV) to understand the mechanisms of charge and particle drift. Finally, surface regeneration was investigated by analyzing images of the contaminated surface, before and after treatment. The results reveal that the regeneration process is influenced by electrical and geometrical parameters and DBD reactor materials. The mechanisms of regeneration were analyzed in-situ by measuring changes in the size and concentration of the generated particles during the process of regeneration

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Defoort, Étienne. "Écoulement électro-aérodynamique d'un aérosol de gouttelettes d'eau dans un réacteur de type pointe-plaque en vue de la récupération de composés chimiques." Thesis, Poitiers, 2020. http://www.theses.fr/2020POIT2278.

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Les décharges couronnes DC et les décharges à barrière diélectrique dans l’air à pression atmosphérique sont souvent utilisées en chimie car elles ont la capacité de produire des réactions chimiques hors-équilibre. Dans certaines conditions, elles peuvent générer un écoulement appelé « vent ionique ». Dans cette thèse, l’effet de l’injection d’un brouillard de gouttelettes d’eau micrométrique dans de tels plasmas est étudié, pour être appliqué à la récupération d’espèce chimique volatile in situ. L’objectif est donc d’étudier la mise en mouvement de l’aérosol par la décharge et sa précipitation sur la paroi d’un réacteur de type pointe-plan, à l’aide d’un dispositif de Vélocimétrie par Image de Particules (PIV) à haute fréquence (20 kHz). Dans un premier temps, la mise en mouvement de l’air par le phénomène de vent ionique est décrite, cet écoulement présentant des propriétés qui dépendent fortement du signal électrique alimentant la décharge (amplitude, fréquence, forme d’onde). Dans un second temps, l’effet du brouillard de gouttelettes d’eau sur la décharge ainsi que l’écoulement du brouillard dans l’espace inter-électrodes sont analysés. On a ainsi pu démontrer que le déplacement des particules était majoritairement dû au vent ionique, mais que le phénomène de précipitation électrostatique n’était pas négligeable, surtout à proximité de la plaque et dans les régions éloignées du centre du jet. Enfin, la quantité d’eau récupérée est évaluée pour différentes configurations de décharges électriques. L’application du procédé à la chimie n’a pu aboutir du fait de l’instabilité de la décharge dans un réacteur fermé à cause du film d’eau, non désiré, se formant sur les parois
DC corona discharges and dielectric barrier discharges (DBD) in air at atmospheric pressure are often used in chemistry due to their capacity to produce non-equilibrium chemical reactions. Under certain conditions, they can generate a flow called “ionic wind”. In this thesis, the effect of injecting a mist of water droplets into such plasmas is studied and applied for in situ volatile chemical species gathering. The objective is to study the motion of the aerosol induced by the discharge and its precipitation on the plate wall of a point-to-plate reactor, by means of a Particles Image Velocimetry (PIV) device at high frequency (20 kHz). First, the acceleration of air by the ionic wind phenomenon is described, this flow exhibiting properties that strongly depend on the electrical signal supplying the discharge (amplitude, frequency and waveform). Secondly, the impact of the water droplets mist on the discharge and the mist flow in the gap between electrodes are analyzed. We demonstrated that the particle movement was mainly due to ionic wind, but that the electrostatic precipitation phenomenon was not negligible, especially close to the plate and in the area far away from the jet axis. Lastly, the amount of water gathered in different discharge setups is evaluated. Applying the process to chemistry did not succeed because the discharge was unstable in a closed reactor due to the water film that takes place on the wall of the reactor

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Book chapters on the topic "Electrostic barriers"

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Shuiliang, Yao, Atoshi Kodama, Shin Yamamoto, Chieko Mine, Yuichi Fujioka, and Chihiro Fushimi. "Application of a Dielectric Barrier Discharge Reactor for Diesel PM Removal." In Electrostatic Precipitation, 677–80. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-540-89251-9_141.

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Chen, Minggong, Yan Lingyan, Wang Xiaoyan, T. Takashima, and A. Mizuno. "The Study on Series of Copper Catalyst in the Reactor of Dielectric Barrier Discharge to Remove NO x." In Electrostatic Precipitation, 685–89. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-540-89251-9_143.

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Jouvet, C., and D. Solgadi. "Photochemistry of van der Waals Complexes and Small Clusters." In Chemical Reactions in Clusters. Oxford University Press, 1996. http://dx.doi.org/10.1093/oso/9780195090048.003.0007.

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In a chemical reaction, the shape of the potential energy surface (PES) dictates the reaction rate and energy disposal in the products. Not only does the dynamics depend crucially upon the features of the surface, but, ultimately one seeks to influence the course of the reaction by preparing selectively certain regions of the surface. For harpooning reactions, the propensity rules for energy disposal in the products (influence of the entrance kinetic energy, effect of the early or late barrier) have been established by Polanyi (1972) and have been used later as guidelines. Here, the surface may easily be modeled in simple terms using long-range electrostatic interaction in the entrance valley. There was, then, need of an experimental method which allows the possibility of observing directly the characteristic regions of this potential energy surface, but also to investigate precisely the surface in other types of reaction. The study of the reactivity of van der Waals complexes is intended to fulfil this purpose. In classical experiments, the surface is obtained by inversion of the experimental data which are differential cross sections and internal energy distribution of the products. This procedure is difficult and not unambiguous. The first step is to determine the correlation between the entrance channel's parameters (kinetic energy, internal energy, angular momentum) and the final states of the products (kinetic energy, internal energy, angular distribution). This requires a precise control of the entrance channel. Therefore, the goal of many experiments is to reduce the initial states to a small subset, and to measure the energy disposal in the products with the greatest accuracy. This was first achieved by controlling the kinetic energy of the reactants in crossed beam experiments. Later, a certain control of the collision geometry was obtained by orienting the molecules or the atomic orbitals in crossed beam experiments or by using prealigned systems in a van der Waals complex: this subject is discussed in Buelow et al. (1986).

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Nitzan, Abraham. "Electron Transfer and Transmission at Molecule–Metal and Molecule–Semiconductor Interfaces." In Chemical Dynamics in Condensed Phases. Oxford University Press, 2006. http://dx.doi.org/10.1093/oso/9780198529798.003.0024.

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This chapter continues our discussion of electron transfer processes, now focusing on the interface between molecular systems and solid conductors. Interest in such processes has recently surged within the emerging field of molecular electronics, itself part of a general multidisciplinary effort on nanotechnology. Notwithstanding new concepts, new experimental and theoretical methods, and new terminology, the start of this interest dates back to the early days of electrochemistry, marked by the famous experiments of Galvani and Volta in the late eighteenth century. The first part of this chapter discusses electron transfer in what might now be called “traditional” electrochemistry where the fundamental process is electron transfer between a molecule or a molecular ion and a metal electrode. The second part constitutes an introduction to molecular electronics, focusing on the problem of molecular conduction, which is essentially electron transfer (in this context better termed electron transmission) between two metal electrodes through a molecular layer or sometimes even a single molecule. In Chapter 16 we have focused on electron transfer processes of the following characteristics: (1) Two electronic states, one associated with the donor species, the other with the acceptor, are involved. (2) Energetics is determined by the electronic energies of the donor and acceptor states and by the electrostatic solvation of the initial and final charge distributions in their electronic and nuclear environments. (3) The energy barrier to the transfer process originates from the fact that electronic and nuclear motions occur on vastly different timescales. (4) Irreversibility is driven by nuclear relaxation about the initial and final electronic charge distributions. How will this change if one of the two electronic species is replaced by a metal? We can imagine an electron transfer process between a metal substrate and a molecule adsorbed on its surface, however the most common process of this kind takes place at the interface between a metal electrode and an electrolyte solution, where the molecular species is an ion residing in the electrolyte, near the metal surface. Electron transfer in this configuration is the fundamental process of electrochemistry.

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Conference papers on the topic "Electrostic barriers"

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Chuan-Fang Jiang, Hai-Ting Li, Zhao-Yu Teng, Gui-Fu Wang, Gang Xiao, Lu-Ge Yin, Yu Chen, Ge Yan, William Li, and Sidney Chou. "Pulse stress testing for ultra-thin MgO barrier magnetic tunnel junctions." In 2007 29th Electrical Overstress/Electrostatic Discharge Symposium (EOS/ESD). IEEE, 2007. http://dx.doi.org/10.1109/eosesd.2007.4401740.

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Naulin, V. "Dynamics of Transport Barriers and ELM-Like Behaviour in Electrostatic Turbulence." In PLASMA PHYSICS: 11th International Congress on Plasma Physics: ICPP2002. AIP, 2003. http://dx.doi.org/10.1063/1.1594016.

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Sou, Akira, Kosuke Sasai, and Tsuyoshi Nakajima. "Effects of Adjacent Printer Heads in Electrostatic Inkjet Printer." In ASME 2002 Joint U.S.-European Fluids Engineering Division Conference. ASMEDC, 2002. http://dx.doi.org/10.1115/fedsm2002-31146.

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In order to develop a high speed printing system, the system must be operated in high frequency, and must have multiple heads in rows. Through the present simulation, it was found that successive shots of high frequency (about 2kHz) were possible. By additional optimization of pulse shape and by decreasing the delay time for switching voltage to rise up, it will be possible to realize much higher speed printer. Then, the effects of adjacent printer heads in a row were investigated. It was found that a distance of 254µm (corresponding to 100dpi) was still not enough to achieve stable and well-controlled ink transportation if no electrostatic barriers in between were assigned in the present head design.

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Muhammad Farooq, Wesley C Hoffmann, Todd W Walker, Bradley K Fritz, Daniel Szumlas, Vincent L Smith, and Cathy A Robinson. "Canopy Penetration and Deposition of Barrier Sprays from Electrostatic and Conventional Sprayers." In 2008 Providence, Rhode Island, June 29 - July 2, 2008. St. Joseph, MI: American Society of Agricultural and Biological Engineers, 2008. http://dx.doi.org/10.13031/2013.24709.

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Zouaghi, Ayyoub, and Noureddine Zouzou. "Submicrometer Particle Penetration in a Miniature Dielectric Barrier Discharge type Electrostatic Precipitator." In 2020 IEEE Industry Applications Society Annual Meeting. IEEE, 2020. http://dx.doi.org/10.1109/ias44978.2020.9334854.

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Beyer, P. "Electrostatic Turbulence and Transport in Edge Plasmas: Bursts and Zonal Flows, Stochastic Field Lines, and Transport Barriers." In PLASMA PHYSICS: 11th International Congress on Plasma Physics: ICPP2002. AIP, 2003. http://dx.doi.org/10.1063/1.1594005.

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Krigmont, Henry V. "Multi-Stage Collector Design and Applications." In International Joint Power Generation Conference collocated with TurboExpo 2003. ASMEDC, 2003. http://dx.doi.org/10.1115/ijpgc2003-40021.

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The Multi Stage Collector (MSC™) concept for ultra-fine particulate control not only retains the best advantages of current state-of-the-art technology but also makes significant improvements. The new MSC™ design provides a synergistic combination of both single- and two-stage electrostatic precipitation while incorporating an additional collector-stage by filtering the gas exiting the collector through a barrier collector-zone. This arrangement ensures that essentially all dust would be detained in this final stage. The MSC™ contains multiple narrow and wide zones formed by a plurality of parallel corrugated plates. Enclosed in the narrow zones are discharge electrodes. These electrodes provide a non-uniform electric field leading to corona discharge. The corona discharge causes particulate matter in the gas flow to become charged. Wide regions contain barrier filters thus creating the two-stage precipitator with relatively uniform electric field. In these regions, particles are collected on both plates and on the porous barrier elements, which also act as the final filtering stage. Results of the applications analyses and future development work are discussed. The gas flow analyses with an aid of the CFD model are presented below.

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Nakamura, Jun. "Energy barrier for dimer flipping at the Si(001)-2 × 1 surface in external electrostatic fields." In PHYSICS OF SEMICONDUCTORS: 27th International Conference on the Physics of Semiconductors - ICPS-27. AIP, 2005. http://dx.doi.org/10.1063/1.1994142.

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Shan, Hua, and Yu-Tai Lee. "Numerical Study of Dielectric Barrier Discharge Plasma Actuation." In ASME 2014 4th Joint US-European Fluids Engineering Division Summer Meeting collocated with the ASME 2014 12th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/fedsm2014-21108.

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There has been an increasing interest in dielectric barrier discharge (DBD) plasma actuation for flow control in the past decade. Compared to other means of active flow controls, the DBD plasma actuations have several advantages, including absence of moving parts, a fast time response for unsteady applications, a very low mass of the device, no cavities or holes on control surfaces, and possibly low energy consumption. These features are especially important for applications with high g-loads, such as turbomachinery blades rotating at high speed. A computational method has been developed to couple a DBD electro-hydrodynamic (EHD) body force model with the Reynolds averaged Navier-Stokes (RANS) model for incompressible flows. The EHD body force model is based on solving the electrostatic equations for the electric potential due to applied voltage and the net charge density due to ionized air. The boundary condition for charge density on the dielectric surface is obtained from a Space-Time Lumped-Element (STLE) circuit model that accounts for time and space dependence of the air ionization on the input voltage amplitude, frequency, electrode geometry, and dielectric properties. Alternatively, an empirical formulation representing a Gaussian distribution of charge density on the dielectric surface can also be used. The EHD body force is calculated using the solutions obtained from solving the electric potential and the net charge density equations. As a comparison, a much simpler Linearized Electric Body Force (LEBF) model is also used to directly specify the spatial distribution of the averaged EHD body force. The coupled computational models have been implemented using a multiple-domain approach. The electric potential equation, the net charge density equation, and the flow equations are solved in separate computational domains. All equations are discretized in space using a cell-centered finite volume method. Parallel computation is implemented using domain-decomposition and message passing interface (MPI). Due to a large disparity in time scales between the electric discharge and the flow, a multiple sub-cycle technique is used in coupling the plasma solver and the flow solver. The DBD plasma induced flow in quiescent air is used as a test case and the computational results are validated against experimental measurement. A comparison between different EHD body force models is also presented. Then, the effect of driving duty-cycles with different waveforms and input voltage amplitudes is investigated in terms of electrical power, EHD thrust, and kinetic energy of induced flow.

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Wilcox, Melissa, David Ransom, Meron Henry, and John Platt. "Engine Distress Detection in Gas Turbines With Electrostatic Sensors." In ASME Turbo Expo 2010: Power for Land, Sea, and Air. ASMEDC, 2010. http://dx.doi.org/10.1115/gt2010-22349.

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Failures in gas turbines such as fretting at combustor assembly interfaces, blade rub, Thermal Barrier Coating (TBC) spalling, minor amounts of domestic or foreign object damage can be detected by mechanical vibration or gas turbine performance degradation, but it is usually too late for damage control by the time the failure is significant enough to be detected with these methods. Electrostatic charge sensors present a potential method for identifying the failure modes at an earlier stage before significant damage has occurred. In a gas turbine, there are potentially two sources of electrostatic charge in the exhaust gas flow stream: ionized plasma that is a natural byproduct of high temperature combustion, and any form of debris that has originated either in the compressor, combustor, or turbine sections of the gas turbine engine as a result of vibration or fatigue. For this reason, the electrostatic charge monitor becomes a very useful device for monitoring both combustion performance problems as well as potential damage related to debris in the exhaust stream. Electrostatic sensing technology has been proven to work in detecting ingested debris and engine debris on aerospace jet engines. However, the use of the sensors in industrial applications has shown that much research is still required especially in the areas of sensor placement and failure identification. This paper discusses results from testing conducted to identify the optimal placement location for the electrostatic charge sensors in a gas turbine exhaust stream. The results are presented for various sensor locations on small (112 kW) and medium (1.185 MW) frame gas turbines to evaluate distance, velocity, radial location, and gas turbine geometry effects. These tests are completed with the gas turbine ingesting varying amounts of TBC upstream of the compressor and administering power level changes to the gas turbine. The results of this experimental program demonstrate a clear sensitivity to sensor placement along the exhaust duct of a gas turbine as well as the radial location. There are variations in the particle flow pathlines in the exhaust duct at different gas turbine operating conditions. These variations influence the sensors response. Best results are obtained when the sensors are placed at the location with the fastest and hottest exhaust gas. Multiple sensors may be required to obtain comprehensive coverage for practical event detection.

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Reports on the topic "Electrostic barriers"

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LaBombard, B., and R. W. Conn. Analysis of an m = 1 electrostatic barrier scrape-off layer as a technique for reducing and controlling the particle and energy losses on the large major radius edge of tokamak. Office of Scientific and Technical Information (OSTI), December 1988. http://dx.doi.org/10.2172/6392444.

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