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.

Small-amplitude supersolitons near supercritical plasma compositions

2017 ◽  
Vol 83 (4) ◽  
Author(s):  
Carel P. Olivier ◽  
Frank Verheest ◽  
Shimul K. Maharaj
Keyword(s):  
Electrostatic Potential ◽  
Taylor Series ◽  
Small Amplitude ◽  
Fluid Model ◽  
Taylor Series Expansion ◽  
Upper Bounds ◽  
Lower And Upper Bounds ◽  
Sagdeev Potential ◽  
Acoustic Speed

Supercritical plasma compositions in parameter space are considered for a general fluid model consisting of an arbitrary number of species. This is done by applying a Taylor series expansion of the Sagdeev potential about the acoustic speed and the equilibrium electrostatic potential. A novel finding in this study is the description of small-amplitude supersolitons. Our analysis allows us to determine the plasma compositional criteria for such structures, as well as lower and upper bounds of their velocities and amplitudes. We therefore establish an interesting link between supercritical plasma compositions and the existence of supersolitons. The results are illustrated via a case study where plasmas consisting of cold ions and two Boltzmann electron species are considered.

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.

Islamic and Jewish Religious Feminists Tackle Islamic and Jewish Oral Law: Maintenance and Rebellion of Wives

2017 ◽  
Vol 11 (1) ◽  
pp. 35-63
Author(s):  
Ruth Roded
Keyword(s):  
State Policy ◽  
Political System ◽  
Daily Life ◽  
The State ◽  
The Political ◽  
Jewish Law ◽  
Modern Times ◽  
Parallel Case ◽  
First Time

Beginning in the early 1970s, Jewish and Muslim feminists, tackled “oral law”—Mishna and Talmud, in Judaism, and the parallel Hadith and Fiqh in Islam, and several analogous methodologies were devised. A parallel case study of maintenance and rebellion of wives —mezonoteha, moredet al ba?ala; nafaqa al-mar?a and nush?z—in classical Jewish and Islamic oral law demonstrates similarities in content and discourse. Differences between the two, however, were found in the application of oral law to daily life, as reflected in “responsa”—piskei halacha and fatwas. In modern times, as the state became more involved in regulating maintenance and disobedience, and Jewish law was backed for the first time in history by a state, state policy and implementation were influenced by the political system and socioeconomic circumstances of the country. Despite their similar origin in oral law, maintenance and rebellion have divergent relevance to modern Jews and Muslims.

scholarly journals Shell-crossing in a ΛCDM Universe

2020 ◽  
Vol 501 (1) ◽  
pp. L71-L75
Author(s):  
Cornelius Rampf ◽  
Oliver Hahn
Keyword(s):  
Dark Matter ◽  
Perturbation Theory ◽  
Large Scale ◽  
Cold Dark Matter ◽  
Three Dimensional ◽  
Random Initial Data ◽  
Recursion Relations ◽  
Indispensable Tool ◽  
First Time ◽  
Very High

ABSTRACT Perturbation theory is an indispensable tool for studying the cosmic large-scale structure, and establishing its limits is therefore of utmost importance. One crucial limitation of perturbation theory is shell-crossing, which is the instance when cold-dark-matter trajectories intersect for the first time. We investigate Lagrangian perturbation theory (LPT) at very high orders in the vicinity of the first shell-crossing for random initial data in a realistic three-dimensional Universe. For this, we have numerically implemented the all-order recursion relations for the matter trajectories, from which the convergence of the LPT series at shell-crossing is established. Convergence studies performed at large orders reveal the nature of the convergence-limiting singularities. These singularities are not the well-known density singularities at shell-crossing but occur at later times when LPT already ceased to provide physically meaningful results.

scholarly journals Erratum: Gravrok, J., et al. Beyond the Benefits of Assistance Dogs: Exploring Challenges Experienced by First-Time Handlers. Animals 2019, 9, 203

Animals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 237
Author(s):  
Jennifer Gravrok ◽  
Dan Bendrups ◽  
Tiffani Howell ◽  
Pauleen Bennett
Keyword(s):  
Assistance Dogs ◽  
First Time

The authors wish to make the following corrections [1]:In Table 1, under case study 4, the code was originally labeled as H8, P8 and ADI 8; these labels should be H4, P4 and ADI 4, respectively [...]

scholarly journals Investigating the Concerns of First-Time Distance Education Instructors

2019 ◽  
Vol 20 (5) ◽  
Author(s):  
Halil Kayaduman ◽  
Turgay Demirel
Keyword(s):  
Distance Education ◽  
Content Knowledge ◽  
Stages Of Concern ◽  
Concerns Based Adoption Model ◽  
Descriptive Case Study ◽  
Time Distance ◽  
Adaptation Processes ◽  
First Time ◽  
Ongoing Concern

The purpose of the study is to investigate the concern developments of first-time distance education instructors using the concerns-based adoption model (CBAM). This study used stages of concern (SoC), a component of CBAM, as its theoretical framework. A descriptive case study was implemented, which focused on the adaptation processes of nine instructors lecturing for the first time via distance education. The instructors attended a two-day training, which was designed based on their initial concerns. Then instructors implemented their courses for four weeks via distance education. While the informational and personal stages (self-concerns) decreased compared to the initial findings, the consequence stage increased in intensity. However, self-concerns remained predominant in the process despite the reduction in self-concerns and increase in the consequence stage. Based on the findings, the implications for distance education and recommendations for addressing the instructors’ concerns are discussed. Recommendations for alleviating the concerns of first-time distance education instructors include: the provision of ongoing concern-based interventions that incorporate technological, pedagogical, and content knowledge; providing working examples related to distance education from which instructors can learn vicariously; and encouraging collaboration among instructors.

scholarly journals Bearing Severity Fault Evaluation Using Contour Maps—Case Study

2021 ◽  
Vol 11 (14) ◽  
pp. 6452
Author(s):  
César Ricardo Soto-Ocampo ◽  
Juan David Cano-Moreno ◽  
José Manuel Mera ◽  
Joaquín Maroto
Keyword(s):  
Health Indicators ◽  
Bearing Faults ◽  
Contour Maps ◽  
Initial Stage ◽  
Critical Components ◽  
Bearing Damage ◽  
First Time ◽  
Current Operating

Increasing industrial competitiveness has led to an increased global interest in condition monitoring. In this sector, rotating machinery plays an important role, where the bearing is one of the most critical components. Many vibration-based signal treatments are already being used to identify features associated with bearing faults. The information embedded in such features are employed in the construction of health indicators, which allow for evaluation of the current operating status of the machine. In this work, the use of contour maps to represent the diagnosis map of a bearing, used as a health map, is presented for the first time. The results show that the proposed method is promising, allowing for the satisfactory detection and evaluation of the severity of bearing damage. In this initial stage of the research, our results suggest that this method can improve the classification of bearing faults and, therefore, optimise maintenance processes.

Are seasonal lakes as productive as permanent lakes? A case study from Ireland

2010 ◽  
Vol 67 (8) ◽  
pp. 1291-1302 ◽  
Author(s):  
Helder Cunha Pereira ◽  
Norman Allott ◽  
Catherine Coxon
Keyword(s):  
Seasonal Variation ◽  
Linear Regression ◽  
Chlorophyll A ◽  
Algal Biomass ◽  
P Limitation ◽  
Underlying Causes ◽  
Western Ireland ◽  
Log Linear ◽  
First Time

This paper compares, for the first time, nutrient levels and chlorophyll a measured in a set of seasonal lakes with those reported for permanent lakes in the literature. Twenty-two turloughs (karstic seasonal lakes) in western Ireland were sampled monthly from the onset of flooding (October) until they dried out (6 to 9 months). The turloughs showed similar levels of nutrients and chlorophyll a to those reported for Irish and international lakes. Chlorophyll a peaked between November and February in the majority of turloughs, sometimes with values higher than those measured in mesotrophic lakes in summer. A significant log-linear regression was found between total phosphorus and chlorophyll a, which suggests P limitation of algal biomass in the majority of the turloughs. The regression characteristics were not significantly different than those described in similar studies of permanent lakes. Patterns in seasonal variation of nutrients are also presented, their underlying causes being discussed in relation to their transport within catchments. Our results show that despite being predominantly winter phenomena, turloughs can be as productive as permanent lakes.

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.

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