Electrostatic supersolitons and double layers at the acoustic speed

2015 ◽  
Vol 22 (1) ◽  
pp. 012301 ◽  
Author(s):  
Frank Verheest ◽  
Manfred A. Hellberg
Keyword(s):  
Double Layers ◽  
Acoustic Speed

Ion-acoustic solitary structures at the acoustic speed in a collisionless magnetized nonthermal dusty plasma

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Debdatta Debnath ◽  
Anup Bandyopadhyay
Keyword(s):  
Double Layer ◽  
Negative Polarity ◽  
Critical Value ◽  
Magnetized Plasma ◽  
Double Layers ◽  
Nonthermal Electrons ◽  
Solitary Structures ◽  
Ion Acoustic ◽  
Density Of Electrons ◽  
Acoustic Speed

Abstract At the acoustic speed, we have investigated the existence of ion-acoustic solitary structures including double layers and supersolitons in a collisionless magnetized plasma consisting of negatively charged static dust grains, adiabatic warm ions, and nonthermal electrons. At the acoustic speed, for negative polarity, the system supports solitons, double layers, supersoliton structures after the formation of double layer, supersoliton structures without the formation of double layer, solitons after the formation of double layer whereas the system supports solitons and supersolitons without the formation of double layer for the case of positive polarity. But it is not possible to get the coexistence of solitary structures (including double layers and supersolitons) of opposite polarities. For negative polarity, we have observed an important transformation viz., soliton before the formation of double layer → double layer → supersoliton → soliton after the formation of double layer whereas for both positive and negative polarities, we have observed the transformation from solitons to supersolitons without the formation of double layer. There does not exist any negative (positive) potential solitary structures within 0 < μ < μ c (μ c < μ < 1) and the amplitude of the positive (negative) potential solitary structure decreases for increasing (decreasing) μ and the solitary structures of both polarities collapse at μ = μ c, where μ c is a critical value of μ, the ratio of the unperturbed number density of electrons to that of ions. Similarly there exists a critical value β e2 of the nonthermal parameter β e such that the solitons of both polarities collapse at β e = β e2.

Asymptotic analysis of solitons and double layers at the acoustic speed

2017 ◽  
Vol 83 (6) ◽  
Author(s):  
Carel P. Olivier ◽  
Frank Verheest ◽  
Shimul K. Maharaj
Keyword(s):  
Asymptotic Behaviour ◽  
Decay Rate ◽  
Double Layer ◽  
Taylor Series Expansion ◽  
The Other ◽  
Double Layers ◽  
Exponential Decay Rate ◽  
Layer Velocity ◽  
Acoustic Speed

In this paper, we consider the asymptotic behaviour of solitons and double layers. By using the Sagdeev pseudopotential formalism, a Taylor series expansion is used to derive the asymptotic behaviour. For solitons and supersolitons that propagate faster than the acoustic speed, an exponential decay rate is derived. In contrast, for acoustic speed solitons and supersolitons, we show that the decay rate is algebraic, resulting in much fatter tails. These results can be extended to double layers. However, the double layer velocity affects only one side of the tail. The other side of the tail is affected by the multiplicity of the double layer root. All the results are illustrated by means of a case study.

A small-amplitude study of solitons near critical plasma compositions

2016 ◽  
Vol 82 (6) ◽  
Author(s):  
Carel P. Olivier ◽  
Frank Verheest ◽  
Shimul K. Maharaj
Keyword(s):  
Perturbation Theory ◽  
Small Amplitude ◽  
Fluid Model ◽  
Taylor Series Expansion ◽  
Double Layers ◽  
Reductive Perturbation ◽  
First Time ◽  
Lorentzian Shape ◽  
Acoustic Speed

The properties of small-amplitude solitons are established near critical plasma compositions in a generalized fluid plasma with an arbitrary number of species. The study is conducted via a Taylor series expansion of the Sagdeev potential. It is shown that there are two types of critical compositions, namely rich critical and poor critical compositions. The coexistence of positive and negative polarity solitons is shown to arise at rich critical compositions and near rich critical compositions. At poor critical compositions, no small-amplitude solitons exist, while weak double layers arise near poor critical compositions. A novel analytical expression is obtained for a small-amplitude acoustic speed soliton solution near rich critical compositions. These solitons have a Lorentzian shape with much fatter tails than regular solitons. A case study is also performed for a simple fluid model consisting of cold ions and two Boltzmann electron species. Exact agreement is obtained between the Sagdeev analysis and reductive perturbation theory. For the first time, we derive the same Lorentzian acoustic speed soliton from reductive perturbation theory.

Coating of continuous carbon fibers with double layers by chemical vapor deposition

2001 ◽  
Vol 11 (PR3) ◽  
pp. Pr3-885-Pr3-892 ◽  
Author(s):  
N. Popovska ◽  
S. Schmidt ◽  
E. Edelmann ◽  
V. K. Wunder ◽  
H. Gerhard ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Carbon Fibers ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Double Layers

Cracking at the fold in double layer coated paper: the influence of latex and starch composition

TAPPI Journal ◽  
2019 ◽  
Vol 18 (2) ◽  
pp. 93-99
Author(s):  
SEYYED MOHAMMAD HASHEMI NAJAFI ◽  
DOUGLAS BOUSFIELD, ◽  
MEHDI TAJVIDI
Keyword(s):  
Mechanical Properties ◽  
Double Layer ◽  
Starch Content ◽  
Single Layer ◽  
Double Layers ◽  
Coated Paper ◽  
Coated Papers ◽  
Coating Layers ◽  
Scanned Images ◽  
Packaging Paper

Cracking at the fold of publication and packaging paper grades is a serious problem that can lead to rejection of product. Recent work has revealed some basic mechanisms and the influence of various parameters on the extent of crack area, but no studies are reported using coating layers with known mechanical properties, especially for double-coated systems. In this study, coating layers with different and known mechanical properties were used to characterize crack formation during folding. The coating formulations were applied on two different basis weight papers, and the coated papers were folded. The binder systems in these formulations were different combinations of a styrene-butadiene latex and mixtures of latex and starch for two different pigment volume concentrations (PVC). Both types of papers were coated with single and double layers. The folded area was scanned with a high-resolution scanner while the samples were kept at their folded angle. The scanned images were analyzed within a constant area. The crack areas were reported for different types of papers, binder system and PVC values. As PVC, starch content, and paper basis weight increased, the crack area increased. Double layer coated papers with high PVC and high starch content at the top layer had more cracks in comparison with a single layer coated paper, but when the PVC of the top layer was low, cracking area decreased. No measurable cracking was observed when the top layer was formulated with a 100% latex layer.

scholarly journals A gateway for ion transport on gas bubbles pinned onto solids

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Veton Haziri ◽  
Tu Pham Tran Nha ◽  
Avni Berisha ◽  
Jean-François Boily
Keyword(s):  
Ion Transport ◽  
Metal Ion ◽  
Electrochemical Impedance ◽  
Gas Bubbles ◽  
Open Circuit ◽  
Double Layers ◽  
Water Geochemistry ◽  
Chemical Potentials ◽  
Pore Water Geochemistry ◽  
Electric Potentials

AbstractGas bubbles grown on solids are more than simple vehicles for gas transport. They are charged particles with surfaces populated with exchangeable ions. We here unveil a gateway for alkali metal ion transport between oxygen bubbles and semi-conducting (iron oxide) and conducting (gold) surfaces. This gateway was identified by electrochemical impedance spectroscopy using an ultramicroelectrode in direct contact with bubbles pinned onto these solid surfaces. We show that this gateway is naturally present at open circuit potentials, and that negative electric potentials applied through the solid enhance ion transport. In contrast, positive potentials or contact with an insulator (polytetrafluoroethylene) attenuates transport. We propose that this gateway is generated by overlapping electric double layers of bubbles and surfaces of contrasting (electro)chemical potentials. Knowledge of this ion transfer phenomenon is essential for understanding electric shielding and reaction overpotential caused by bubbles on catalysts. This has especially important ramifications for predicting processes including mineral flotation, microfluidics, pore water geochemistry, and fuel cell technology.

Crystal structure of pomalidomide Form I, C13H11N3O4

2021 ◽  
pp. 1-6
Author(s):  
James A. Kaduk ◽  
Amy M. Gindhart ◽  
Thomas N. Blanton
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Powder Diffraction ◽  
Density Functional ◽  
Double Layers ◽  
Carbonyl Groups ◽  
Hydrogen Atoms ◽  
Powder Diffraction File ◽  
Functional Theory ◽  
Amine Hydrogen

The crystal structure of pomalidomide Form I has been solved and refined using synchrotron X-ray powder diffraction data and optimized using density functional theory techniques. Pomalidomide Form I crystallizes in the space group P-1 (#2) with a = 7.04742(9), b = 7.89103(27), c = 11.3106(6) Å, α = 73.2499(13), β = 80.9198(9), γ = 88.5969(6)°, V = 594.618(8) Å3, and Z = 2. The crystal structure is characterized by the parallel stacking of planes parallel to the bc-plane. Hydrogen bonds link the molecules into double layers also parallel to the bc-plane. Each of the amine hydrogen atoms acts as a donor to a carbonyl group in an N–H⋯O hydrogen bond, but only two of the four carbonyl groups act as acceptors in such hydrogen bonds. Other carbonyl groups participate in C–H⋯O hydrogen bonds. The powder pattern has been submitted to ICDD® for inclusion in the Powder Diffraction File™ (PDF®).

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