The Evolution of a Horizontal Scale for Oscillatory Magnetoconvection

1989 ◽  
Vol 8 (1) ◽  
pp. 25-28 ◽  
Author(s):  
J.O. Murphy ◽  
J.M. Lopez
Keyword(s):  
Horizontal Cell ◽  
Complex Interaction ◽  
Oscillatory Convection ◽  
Horizontal Scale ◽  
The Past ◽  
Magnetic Prandtl Number ◽  
Non Linear ◽  
Convective Motions ◽  
Convective Cells ◽  
Conductive State

AbstractOscillatory convective motions have been observed in the umbrae of sunspots and, in the past, the linear theory of overstability has been used for sunspot models. Here a non-linear model for oscillatory convection has been used to investigate the possibility of a preferred horizontal cell size for these motions, in the presence of a magnetic field.The integration forward in time, from the conductive state, of the non-linear multimode equations governing magnetoconvection when the magnetic Prandtl number is less than one portrays a complex interaction between the evolving magnetic and vertical velocity horizontal scales. Preferred horizontal scales for the convective cells have been established by identifying the modes that substantially contribute to the overall convective heat transport. All other modes, although initially perturbed, in time essentially decay to zero through self interaction.

Evolution of a Horizontal Scale for Magnetoconvection

1987 ◽  
Vol 7 (2) ◽  
pp. 112-116 ◽  
Author(s):  
J. O. Murphy ◽  
J. M. Lopez
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Discrete Spectrum ◽  
Fluid Layer ◽  
Horizontal Cell ◽  
Horizontal Scale ◽  
Wave Numbers ◽  
Horizontal Wave ◽  
Convective Motions ◽  
The Magnetic Field

AbstractThe non-linear modal equations governing magnetoconvection in a fluid layer have been integrated forward in time incorporating a discrete spectrum of horizontal wave numbers, distributed within the range supporting convection. By progressively deleting some of the decaying modes and introducting additional modes within the range of growth it is possible to establish the evolution, or otherwise, of a preferred horizontal scale, which determines the horizontal cell size of the convective motions. Further, the influence of the magnetic field strength on cell extent can also be determined.

In search of lost space: The process of space planning through remembering and history

Organization ◽  
2015 ◽  
Vol 23 (1) ◽  
pp. 71-89 ◽  
Author(s):  
Fabio James Petani ◽  
Jeanne Mengis
Keyword(s):  
Production Of Space ◽  
Space Planning ◽  
The Past ◽  
Time Space ◽  
Non Linear ◽  
Over Time ◽  
Contested Narratives

This article explores the role of remembering and history in the process of planning new spaces. We trace how the organizational remembering of past spaces enters the conception (i.e. planning) of a large culture center. By drawing on Henri Lefebvre’s reflections on history, time and memory, we analyze the processual interconnections of his spatial triad, namely between the planned, practiced, and lived moments of the production of space. We find that over time space planning involves recurrent, changing, and contested narratives on ‘lost spaces’, remembering happy spaces of the past that articulate a desire to regain them. The notion of lost space adds to our understanding of how space planning involves, through organizational remembering, a sociomaterial and spatiotemporal work of relating together different spaces and times in non-linear narratives of repetition.

Conversion, Palinody, Traces

2021 ◽  
pp. 528-545
Author(s):  
Jennifer Rushworth
Keyword(s):  
The Past ◽  
Non Linear

Taking three terms which represent different ways of relating to experience, time, and narration, this chapter proposes attention to what remains, in the form traces, against the pressure of conversion which requires, instead, a complete break with the past. Traces are here understood as vestiges or footprints, with literal and metaphorical implications inspired by Sigmund Freud’s reading of Gradiva’s footsteps in his essay on Jensen’s novel, and followed back to Beatrice’s footsteps in Vita Nova and Inferno. Just as Freud understands Pompeii as a symbol of a force which is at once destructive and preservative—in other words, repression—, so this chapter shows that palinody in Dante is a mechanism that conserves as well as hides. The resultant understanding of Dante’s works is volcanic as well as non-linear.

Approximations and boundary conditions for continuous-time threshold autoregressive processes

1994 ◽  
Vol 31 (4) ◽  
pp. 1103-1109 ◽  
Author(s):  
Rob J. Hyndman
Keyword(s):  
Time Series ◽  
Boundary Conditions ◽  
Continuous Time ◽  
Linear Time ◽  
Autoregressive Processes ◽  
Threshold Autoregressive ◽  
The Past ◽  
Time Threshold ◽  
Non Linear ◽  
The Way

Continuous-time threshold autoregressive (CTAR) processes have been developed in the past few years for modelling non-linear time series observed at irregular intervals. Several approximating processes are given here which are useful for simulation and inference. Each of the approximating processes implicitly defines conditions on the thresholds, thus providing greater understanding of the way in which boundary conditions arise.

scholarly journals How to deal with non-linear pathways towards energy futures

2019 ◽  
Vol 28 (3) ◽  
pp. 20-26
Author(s):  
Stefan Vögele ◽  
Witold-Roger Poganietz ◽  
Philip Mayer
Keyword(s):  
Policy Advice ◽  
Linear Extrapolation ◽  
Energy Futures ◽  
The Past ◽  
Non Linear ◽  
Simplifying Assumptions ◽  
Novel Approaches ◽  
The Creation ◽  
Linear Trends

Energy scenarios currently in use for policy advice are based on a number of simplifying assumptions. This includes, in particular, the linear extrapolation of trends. However, this approach ignores the fact that central variables were highly dynamic in the past. For an assessment of energy futures and the specification of measures, novel approaches are necessary which can implement non-linear trends. In this paper, we show how cross-impact balance (CIB) analysis can be applied to map dynamic trends. Using a small CIB model, we highlight the need for novel approaches in the creation and evaluation of energy futures and the possible contribution of CIB analysis.

The Static Aeroelasticity of Slender Configurations

1963 ◽  
Vol 14 (1) ◽  
pp. 75-104 ◽  
Author(s):  
G. J. Hancock
Keyword(s):  
Static Stability ◽  
Aerodynamic Forces ◽  
Flexible Aircraft ◽  
The Past ◽  
Plate Models ◽  
Non Linear ◽  
The Future ◽  
Static Aeroelasticity ◽  
Definition Of ◽  
Image Position

SummaryThe validity and applicability of the static margin (stick fixed) Kn,where as defined by Gates and Lyon is shown to be restricted to the conventional flexible aircraft. Alternative suggestions for the definition of static margin are put forward which can be equally applied to the conventional flexible aircraft of the past and the integrated flexible aircraft of the future. Calculations have been carried out on simple slender plate models with both linear and non-linear aerodynamic forces to assess their static stability characteristics.

Telling the Traumas of History

2017 ◽  
Author(s):  
Joanne Lipson Freed
Keyword(s):  
Cognitive Distortions ◽  
Leslie Marmon Silko ◽  
Careful Analysis ◽  
Arundhati Roy ◽  
The Third ◽  
The Past ◽  
Non Linear ◽  
Third Person ◽  
Small Things ◽  
The Third Person

Focusing on the novels Ceremony, by Leslie Marmon Silko, and The God of Small Things, by Arundhati Roy, Chapter 2 uses trauma theory to explore how histories of imperial domination refuse to be confined to the past. These two novels invite readers to identify to varying degrees with their traumatized protagonists, holding out the possibility of a resistant and revisionary “history from below.” Ultimately, however, a careful analysis of these two works reveals how literary trauma theorists, in their eagerness to give voice to the voiceless, are too readily taken in by the imaginative construct of the third-person narrator. While individual characters in these novels may suffer the cognitive distortions of trauma, the fragmentary, non-linear account that their readers receive is, in both cases, mediated by the presence of a narrator whose choices are conscious, volitional, and strategic.

scholarly journals On the Dynamics of the Solar Convection Zone

1980 ◽  
Vol 51 ◽  
pp. 15-16
Author(s):  
Bernard R. Durney ◽  
Hendrik C. Spruit
Keyword(s):  
Distribution Function ◽  
Energy Equation ◽  
Convection Zone ◽  
Turbulent Viscosity ◽  
Rotating Stars ◽  
Solar Convection Zone ◽  
Solar Convection ◽  
Convective Motions ◽  
The Mean ◽  
Convective Cells

AbstractWe derive expressions for the turbulent viscosity and turbulent conductivity applicable to convection zones of rotating stars. We assume that the dimensions of the convective cells are known and derive a simple distribution function for the turbulent convective velocities under the influence of rotation. From this distribution function (which includes, in particular, the stabilizing effect of rotation on convection) we calculate in the mixing-length approximation: i) the turbulent Reynolds stresstensor and ii) the expression for the heat flux in terms of the superadiabatic gradient. The contributions of the turbulent convective motions to the mean momentum and energy equation are treated consistently, and assumptions about the turbulent viscosity and heat transport are replaced by assumptions about the turbulent flow itself. The free parameters in our formalism are the relative cell sizes and their dependence on depth and latitude.

21st century psychiatry: The need for a unitary framework

2016 ◽  
Vol 33 (S1) ◽  
pp. S3-S3
Author(s):  
M. Maj
Keyword(s):  
Mental Disorders ◽  
Protective Factors ◽  
21St Century ◽  
Complex Interaction ◽  
Diagnostic Systems ◽  
The Third ◽  
The Past ◽  
Fourth Level ◽  
Competing Interest ◽  
The Moment

While the plurality of approaches is a richness of psychiatry, we need today a unitary framework in which the vast majority of psychiatrists are able to place and recognize themselves. An essential component of this framework should be the awareness that a major outcome of research efforts of the past thirty years is the notion that a simple deterministic etiological model cannot be applied to mental disorders, which instead represent the product of the complex interaction of a multiplicity of vulnerability and protective factors of different nature (biological, intrapsychic, interpersonal, psychosocial). Most current significant etiological research in psychiatry can be accommodated within this framework, thus appearing much less chaotic, inconsistent and fragmentary. This first level of the framework affects in a probabilistic, not a deterministic, way the second one, that of neurobiological, cognitive and psychological intermediate processes. It is unavoidable that different languages be used to describe these processes, but these languages may be translatable into each other to some extent. Furthermore, comprehensive pathogenetic models usually require the integration of different languages. This second level leads, again in a probabilistic way, to the third level, that of symptoms, signs, cognitive dysfunctions and psychopathological dimensions. These are the elements composing the fourth level, the syndromal one. The ICD/DSM formulation of this fourth level is not optimal, but it is the best we have at the moment. Certainly, the fact that two major diagnostic systems exist in psychiatry adds to the confusion and the uncertainty, and should be overcome in the future.Disclosure of interestThe author has not supplied his declaration of competing interest.

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