scholarly journals A Comprehensive Review of the Influence of Electric Field on Flame Characteristics

2020 ◽  
Author(s):  
Yin Ma ◽  
Tong Li ◽  
Jun Yan ◽  
Xiaorong Wang ◽  
Ji Gao ◽  
...  
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Three Dimensional ◽  
Combustion Efficiency ◽  
Two Dimensions ◽  
Three Dimensional Model ◽  
High Pressure And Temperature ◽  
Soot Particles ◽  
Flame Dynamics ◽  
Important Means

Electric field assisted combustion is an important means to improve fuel combustion efficiency. This paper conducts extensive research on flame characteristics under different forms and different application methods of electric fields, emission of soot particles and simulation status. Different flame parameter measurement methods will lead to different degrees of error, and perfect numerical simulation can make simple predictions on experimental data. Most of the current numerical simulations are in two dimensions, and it is necessary to develop a complete and accurate three-dimensional model to simulate and predict the characteristics of the flame under an electric field. The emission of soot particles is also affected by the electric field, and reasonable electric field parameters can greatly reduce the emission of soot particles. It is recommended to conduct centralized measurement of different fuels under the electric field under high pressure and temperature conditions, so as to be able to develop a wider and more accurate flame dynamics and chemical model under the electric field.

Tuning the Electric Field Response of MOFs by Rotatable Dipolar Linkers

2019 ◽  
Author(s):  
Johannes P. Dürholt ◽  
Babak Farhadi Jahromi ◽  
Rochus Schmid
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Structural Changes ◽  
Dielectric Behavior ◽  
Two Dimensions ◽  
Dielectric Constants ◽  
Electric Response ◽  
Dipole Strength ◽  
Metal Organic ◽  
Dynamics Simulations

Recently the possibility of using electric fields as a further stimulus to trigger structural changes in metal-organic frameworks (MOFs) has been investigated. In general, rotatable groups or other types of mechanical motion can be driven by electric fields. In this study we demonstrate how the electric response of MOFs can be tuned by adding rotatable dipolar linkers, generating a material that exhibits paralectric behavior in two dimensions and dielectric behavior in one dimension. The suitability of four different methods to compute the relative permittivity κ by means of molecular dynamics simulations was validated. The dependency of the permittivity on temperature T and dipole strength μ was determined. It was found that the herein investigated systems exhibit a high degree of tunability and substantially larger dielectric constants as expected for MOFs in general. The temperature dependency of κ obeys the Curie-Weiss law. In addition, the influence of dipolar linkers on the electric field induced breathing behavior was investigated. With increasing dipole moment, lower field strength are required to trigger the contraction. These investigations set the stage for an application of such systems as dielectric sensors, order-disorder ferroelectrics or any scenario where movable dipolar fragments respond to external electric fields.

scholarly journals BEM Modelling of High Voltage ELF electric field applied to a 3D pregnant woman model

2010 ◽  
Vol 6 (1) ◽  
pp. 31 ◽  
Author(s):  
Cristina Peratta ◽  
Andres Peratta ◽  
Dragan Poljak
Keyword(s):  
Pregnant Woman ◽  
Electric Field ◽  
Electric Fields ◽  
High Voltage ◽  
Medical Information ◽  
Three Dimensional ◽  
Low Frequency ◽  
Element Model ◽  
The Body ◽  
Geometrical Properties

The paper introduces a three dimensional multidomainboundary element model of a pregnant woman and foetus for the analysis of exposure to high voltage extremely low frequency electric fields. The definition of the differentphysical and geometrical properties of the relevant tissues is established according to medical information available in existing literature. The model takes into account changes in geometry, body mass, body fat, and overall chemical composition in the body which influence the electrical properties, throughout the different gestational periods. The developed model is used to solve the case of exposure to overhead power transmission lines at different stages of pregnancy including weeks 8, 13, 26 and 38. The results obtained are in line with those published in the earlier works considering different approaches. In addition, a sensitivity analysis involving varying scenarios of conductivity, foetus postures and geometry for each stage is defined and solved. Finally, a correlation between the externally applied electric field and the current density inside the foetus is established and the zones of maximum exposure are identified.

scholarly journals Electrical and Polarimetric Radar Observations of a Multicell Storm in TELEX

2007 ◽  
Vol 135 (7) ◽  
pp. 2525-2544 ◽  
Author(s):  
Eric C. Bruning ◽  
W. David Rust ◽  
Terry J. Schuur ◽  
Donald R. MacGorman ◽  
Paul R. Krehbiel ◽  
...  
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Negative Charge ◽  
Positive Charge ◽  
Three Dimensional ◽  
Phase Region ◽  
Polarimetric Radar ◽  
Radar Observations ◽  
Mapping Array ◽  
Lightning Initiation

Abstract On 28–29 June 2004 a multicellular thunderstorm west of Oklahoma City, Oklahoma, was probed as part of the Thunderstorm Electrification and Lightning Experiment field program. This study makes use of radar observations from the Norman, Oklahoma, polarimetric Weather Surveillance Radar-1988 Doppler, three-dimensional lightning mapping data from the Oklahoma Lightning Mapping Array (LMA), and balloon-borne vector electric field meter (EFM) measurements. The storm had a low flash rate (30 flashes in 40 min). Four charge regions were inferred from a combination of LMA and EFM data. Lower positive charge near 4 km and midlevel negative charge from 4.5 to 6 km MSL (from 0° to −6.5°C) were generated in and adjacent to a vigorous updraft pulse. Further midlevel negative charge from 4.5 to 6 km MSL and upper positive charge from 6 to 8 km (from −6.5° to −19°C) were generated later in quantity sufficient to initiate lightning as the updraft decayed. A negative screening layer was present near the storm top (8.5 km MSL, −25°C). Initial lightning flashes were between lower positive and midlevel negative charge and started occurring shortly after a cell began lofting hydrometeors into the mixed phase region, where graupel was formed. A leader from the storm’s first flash avoided a region where polarimetric radar suggested wet growth and the resultant absence of noninductive charging of those hydrometeors. Initiation locations of later flashes that propagated into the upper positive charge tracked the descending location of a polarimetric signature of graupel. As the storm decayed, electric fields greater than 160 kV m−1 exceeded the minimum threshold for lightning initiation suggested by the hypothesized runaway breakdown process at 5.5 km MSL, but lightning did not occur. The small spatial extent (≈100 m) of the large electric field may not have been sufficient to allow runaway breakdown to fully develop and initiate lightning.

scholarly journals Nonperturbative Kinetic Description of Electron-Hole Excitations in Graphene in a Time Dependent Electric Field of Arbitrary Polarization

Particles ◽  
2019 ◽  
Vol 2 (2) ◽  
pp. 208-230 ◽  
Author(s):  
Stanislav A. Smolyansky ◽  
Anatolii D. Panferov ◽  
David B. Blaschke ◽  
Narine T. Gevorgyan
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Kinetic Equations ◽  
Nonlinear Effects ◽  
Two Dimensions ◽  
Time Dependent ◽  
Polarization Current ◽  
Kinetic Description ◽  
Orthogonal Direction ◽  
Electron Hole

On the basis of the well-known kinetic description of e − e + vacuum pair creation in strong electromagnetic fields in D = 3 + 1 QED we construct a nonperturbative kinetic approach to electron-hole excitations in graphene under the action of strong, time-dependent electric fields. We start from the simplest model of low-energy excitations around the Dirac points in the Brillouin zone. The corresponding kinetic equations are analyzed by nonperturbative analytical and numerical methods that allow to avoid difficulties characteristic for the perturbation theory. We consider different models for external fields acting in both, one and two dimensions. In the latter case we discuss the nonlinear interaction of the orthogonal currents in graphene which plays the role of an active nonlinear medium. In particular, this allows to govern the current in one direction by means of the electric field acting in the orthogonal direction. Investigating the polarization current we detected the existence of high frequency damped oscillations in a constant external electric field. When the electric field is abruptly turned off residual inertial oscillations of the polarization current are obtained. Further nonlinear effects are discussed.

Tuning the Electric Field Response of MOFs by Rotatable Dipolar Linkers

2019 ◽  
Author(s):  
Johannes P. Dürholt ◽  
Babak Farhadi Jahromi ◽  
Rochus Schmid
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Structural Changes ◽  
Dielectric Behavior ◽  
Two Dimensions ◽  
Dielectric Constants ◽  
Electric Response ◽  
Dipole Strength ◽  
Metal Organic ◽  
Dynamics Simulations

Recently the possibility of using electric fields as a further stimulus to trigger structural changes in metal-organic frameworks (MOFs) has been investigated. In general, rotatable groups or other types of mechanical motion can be driven by electric fields. In this study we demonstrate how the electric response of MOFs can be tuned by adding rotatable dipolar linkers, generating a material that exhibits paralectric behavior in two dimensions and dielectric behavior in one dimension. The suitability of four different methods to compute the relative permittivity κ by means of molecular dynamics simulations was validated. The dependency of the permittivity on temperature T and dipole strength μ was determined. It was found that the herein investigated systems exhibit a high degree of tunability and substantially larger dielectric constants as expected for MOFs in general. The temperature dependency of κ obeys the Curie-Weiss law. In addition, the influence of dipolar linkers on the electric field induced breathing behavior was investigated. With increasing dipole moment, lower field strength are required to trigger the contraction. These investigations set the stage for an application of such systems as dielectric sensors, order-disorder ferroelectrics or any scenario where movable dipolar fragments respond to external electric fields.

scholarly journals Capillary-induced deformations of a thin elastic sheet

2016 ◽  
Vol 374 (2066) ◽  
pp. 20150169 ◽  
Author(s):  
N. D. Brubaker ◽  
J. Lega
Keyword(s):  
Finite Thickness ◽  
Three Dimensional ◽  
Two Dimensions ◽  
System Of Equations ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Drop Volume ◽  
Exactly Solvable ◽  
Encapsulation Process

We develop a three-dimensional model for capillary origami systems in which a rectangular plate has finite thickness, is allowed to stretch and undergoes small deflections. This latter constraint limits our description of the encapsulation process to its initial folding phase. We first simplify the resulting system of equations to two dimensions by assuming that the plate has infinite aspect ratio, which allows us to compare our approach to known two-dimensional capillary origami models for inextensible plates. Moreover, as this two-dimensional model is exactly solvable, we give an expression for its solution in terms of its parameters. We then turn to the full three-dimensional model in the limit of small drop volume and provide numerical simulations showing how the plate and the drop deform due to the effect of capillary forces.

scholarly journals CHAOS IN A THREE-DIMENSIONAL VOLTERRA–GAUSE MODEL OF PREDATOR–PREY TYPE

2005 ◽  
Vol 15 (05) ◽  
pp. 1689-1708 ◽  
Author(s):  
JEAN-MARC GINOUX ◽  
BRUNO ROSSETTO ◽  
JEAN-LOUIS JAMET
Keyword(s):  
Three Dimensional ◽  
Period Doubling ◽  
Prey Type ◽  
Slow Manifold ◽  
Two Dimensions ◽  
Dimensional Model ◽  
Top Predator ◽  
Three Dimensional Model ◽  
Predator Prey ◽  
Consistent Model

The aim of this paper is to present results concerning a three-dimensional model including a prey, a predator and top-predator, which we have named the Volterra–Gause model because it combines the original model of V. Volterra incorporating a logisitic limitation of the P. F. Verhulst type on growth of the prey and a limitation of the G. F. Gause type on the intensity of predation of the predator on the prey and of the top-predator on the predator. This study highlights that this model has several Hopf bifurcations and a period-doubling cascade generating a snail shell-shaped chaotic attractor.With the aim of facilitating the choice of the simplest and most consistent model a comparison is established between this model and the so-called Rosenzweig–MacArthur and Hastings–Powell models. Many resemblances and differences are highlighted and could be used by the modellers.The exact values of the parameters of the Hopf bifurcation are provided for each model as well as the values of the parameters making it possible to carry out the transition from a typical phase portrait characterizing one model to another (Rosenzweig–MacArthur to Hastings–Powell and vice versa).The equations of the Volterra–Gause model cannot be derived from those of the other models, but this study shows similarities between the three models. In cases in which the top-predator has no effect on the predator and consequently on the prey, the models can be reduced to two dimensions. Under certain conditions, these models present slow–fast dynamics and their attractors are lying on a slow manifold surface, the equation of which is given.

scholarly journals Resistive MHD reconstruction of two-dimensional coherent structures in space

2010 ◽  
Vol 28 (11) ◽  
pp. 2113-2125 ◽  
Author(s):  
W.-L. Teh ◽  
B. U. Ö. Sonnerup ◽  
J. Birn ◽  
R. E. Denton
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Synthetic Data ◽  
Two Dimensions ◽  
Mhd Equations ◽  
Numerical Code ◽  
Reconstruction Technique ◽  
Two Dimensional ◽  
Geomagnetic Tail ◽  
Spacecraft Spin

Abstract. We present a reconstruction technique to solve the steady resistive MHD equations in two dimensions with initial inputs of field and plasma data from a single spacecraft as it passes through a coherent structure in space. At least two components of directly measured electric fields (the spacecraft spin-plane components) are required for the reconstruction, to produce two-dimensional (2-D) field and plasma maps of the cross section of the structure. For convenience, the resistivity tensor η is assumed diagonal in the reconstruction coordinates, which allows its values to be estimated from Ohm's law, E+v×B=η·j. In the present paper, all three components of the electric field are used. We benchmark our numerical code by use of an exact, axi-symmetric solution of the resistive MHD equations and then apply it to synthetic data from a 3-D, resistive, MHD numerical simulation of reconnection in the geomagnetic tail, in a phase of the event where time dependence and deviations from 2-D are both weak. The resistivity used in the simulation is time-independent and localized around the reconnection site in an ellipsoidal region. For the magnetic field, plasma density, and pressure, we find very good agreement between the reconstruction results and the simulation, but the electric field and plasma velocity are not predicted with the same high accuracy.

Three-dimensional Model of Escherichia coli Gyrase B Subunit Crystallized in Two-dimensions on Novobiocin-Linked Phospholipid Films

1994 ◽  
Vol 236 (2) ◽  
pp. 618-628 ◽  
Author(s):  
Hervé Celia ◽  
Laurence Hoermann ◽  
Patrick Schultz ◽  
Luc Lebeau ◽  
Véronique Mallouh ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Three Dimensional ◽  
Two Dimensions ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
B Subunit

scholarly journals Critical Discourse Analysis of Imran Khan Dharna Speeches in Socio-Political Perspective

sjesr ◽  
2020 ◽  
Vol 3 (1) ◽  
pp. 9-19
Author(s):  
Aasia Nusrat ◽  
Sardaraz Khan ◽  
Ms. Shaista Shehzadi
Keyword(s):  
Critical Discourse Analysis ◽  
Theoretical Perspective ◽  
Three Dimensional ◽  
Two Dimensions ◽  
Critical Discourse ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Modal Verbs ◽  
Political Perspective ◽  
The Government

This study aims to explore and uncover power play in Dharna 2014 speeches of Imran Khan. The study has followed the theoretical perspective of power (Fairclough, 2003) in its two-dimensions i.e. power within and behind discourse. This research is significant in terms of enabling common public of Pakistan to understand their leader in terms of the concept of power by comprehending the meaning that language conveys. The research method applies thematic analysis and utilizes Fairclough’s three-dimensional model (1989) as data analyzing tool. The speeches were analyzed by considering Textual, Discursive and Societal levels of discourse. The key findings in case of power within discourse include that the speaker showed the use of pronoun ‘I’ in order to show his power and by using the pronoun ‘we’ he gained the support of the audience in order to win their hearts and reflect this as a power on the rulers. The speakers explained in detail the unjust rule of the government by using different linguistic tools like modal verbs, vocabulary, transitivity, inter-discourse etc. Moreover, in case of power behind discourse, the key findings include the power of west and Islam in the speaker’s speeches.

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