Electrical Conductivity of Strongly Coupled Model and Real Plasmas

2002 ◽  
pp. 561-564
Author(s):  
I. M. Tkachenko ◽  
P. Fernández de Córdoba
Keyword(s):  
Electrical Conductivity ◽  
Coupled Model ◽  
Strongly Coupled

scholarly journals Computational modeling of the electromechanical response of a ventricular fiber affected by eccentric hypertrophy

2017 ◽  
Vol 8 (1) ◽  
pp. 185-209
Author(s):  
Fabrizio Del Bianco ◽  
Piero Colli Franzone ◽  
Simone Scacchi ◽  
Lorenzo Fassina
Keyword(s):  
Coupled Model ◽  
Electrical Current ◽  
Mechanoelectric Feedback ◽  
Isotonic Contraction ◽  
Strongly Coupled ◽  
One Dimensional ◽  
Electromechanical Responses ◽  
Eccentric Hypertrophy ◽  
Dimensional Finite Element ◽  
Simulation Results

AbstractThe aim of this work is to study the effects of eccentric hypertrophy on the electromechanics of a single myocardial ventricular fiber by means of a one-dimensional finite-element strongly-coupled model. The electrical current ow model is written in the reference configuration and it is characterized by two geometric feedbacks, i.e. the conduction and convection ones, and by the mechanoelectric feedback due to stretchactivated channels. First, the influence of such feedbacks is investigated for both a healthy and a hypertrophic fiber in case of isometric simulations. No relevant discrepancies are found when disregarding one or more feedbacks for both fibers. Then, all feedbacks are taken into account while studying the electromechanical responses of fibers. The results from isometric tests do not point out any notable difference between the healthy and hypertrophic fibers as regards the action potential duration and conduction velocity. The length-tension relationships show increased stretches and reduced peak values for tension instead. The tension-velocity relationships derived from afterloaded isotonic and quick- release tests depict higher values of contraction velocity at smaller afterloads. Moreover, higher maximum shortenings are achieved during the isotonic contraction. In conclusion, our simulation results are innovative in predicting the electromechanical behavior of eccentric hypertrophic fibers.

scholarly journals Strongly Coupled Assimilation of a Hypothetical Ocean Current Observing Network within a Regional Ocean-Atmosphere Coupled Model: An OSSE Case Study of Typhoon Hato

2021 ◽  
Author(s):  
Luke Phillipson ◽  
Yi Li ◽  
Ralf Toumi
Keyword(s):  
Coupled Model ◽  
Ocean Currents ◽  
Hf Radar ◽  
Ocean Current ◽  
Coastal Current ◽  
Strongly Coupled ◽  
Ocean Atmosphere ◽  
Atmospheric Observations ◽  
Surface Drifters ◽  
The Impact

AbstractThe forecast of tropical cyclone (TC) intensity is a significant challenge. In this study, we showcase the impact of strongly coupled data assimilation with hypothetical ocean currents on analyses and forecasts of Typhoon Hato (2017). Several observation simulation system experiments were undertaken with a regional coupled ocean-atmosphere model. We assimilated combinations of (or individually) a hypothetical coastal current HF radar network, a dense array of drifter floats and minimum sea-level pressure. During the assimilation, instant updates of many important atmospheric variables (winds and pressure) are achieved from the assimilation of ocean current observations using the cross-domain error covariance, significantly improving the track and intensity analysis of Typhoon Hato. As compared to a control experiment (with no assimilation), the error of minimum pressure decreased by up to 13 hPa (4 hPa / 57 % on average). The maximum wind speed error decreased by up to 18 knots (5 knots / 41 % on average). By contrast, weakly coupled implementations cannot match these reductions (10% on average). Although traditional atmospheric observations were not assimilated, such improvements indicate there is considerable potential in assimilating ocean currents from coastal HF radar, and surface drifters within a strongly coupled framework for intense landfalling TCs.

scholarly journals Facilitating Strongly Coupled Ocean–Atmosphere Data Assimilation with an Interface Solver

2015 ◽  
Vol 144 (1) ◽  
pp. 3-20 ◽  
Author(s):  
Sergey Frolov ◽  
Craig H. Bishop ◽  
Teddy Holt ◽  
James Cummings ◽  
David Kuhl
Keyword(s):  
Data Assimilation ◽  
Impact Analysis ◽  
Coupled Model ◽  
Deep Ocean ◽  
Accurate Solution ◽  
Fluid Interface ◽  
Strongly Coupled ◽  
Grid Points ◽  
Coupled Data Assimilation ◽  
Observation Vector

Abstract In a strongly coupled data assimilation (DA), a cross-fluid covariance is specified that allows measurements from a coupled fluid (e.g., atmosphere) to directly impact analysis increments in a target fluid (e.g., ocean). The exhaustive solution to this coupled DA problem calls for a covariance where all available measurements can influence all grid points in all fluids. Solution of such a large algebraic problem is computationally expensive, often calls for a substantial rewrite of existing fluid-specific DA systems, and, as shown in this paper, can be avoided. The proposed interface solver assumes that covariances between coupled measurements and target fluid are often close to null (e.g., between stratospheric observations and the deep ocean within a 6-h forecast cycle). In the interface solver, two separate DA solvers are run in parallel: one that produces an analysis solution in the atmosphere, and one in the ocean. Each system uses a coupled observation vector where in addition to resident measurements in the target fluid it also includes nonresident measurements in the coupled fluid that are likely to have significant influence on the analysis in the target fluid (interface measurements). An ensemble-based method is employed and a localization function for coupled ensembles is proposed. Using a coupled model for the Mediterranean Sea (in a twin setting), it is demonstrated that (i) the solution of the interface solver converges to the exhaustive solution and (ii) that in presence of poorly known error covariances, the interface solver can be configured to produce a more accurate solution than an exhaustive solver.

A Magneto-Mechanical Strongly Coupled Model for Giant Magnetostrictive Force Sensor

2007 ◽  
Vol 43 (4) ◽  
pp. 1437-1440 ◽  
Author(s):  
Qingxin Yang ◽  
Rongge Yan ◽  
Changzai Fan ◽  
Haiyan Chen ◽  
Fugui Liu ◽  
...  
Keyword(s):  
Coupled Model ◽  
Force Sensor ◽  
Strongly Coupled

Calculation of the electrical conductivity of strongly coupled plasmas

1996 ◽  
Vol 53 (1) ◽  
pp. 1059-1067 ◽  
Author(s):  
J. K. Yuan ◽  
Y. S. Sun ◽  
S. T. Zheng
Keyword(s):  
Electrical Conductivity ◽  
Strongly Coupled ◽  
Strongly Coupled Plasmas ◽  
Coupled Plasmas

CFD Modeling of a Gas Turbine Combustor From Compressor Exit to Turbine Inlet

1999 ◽  
Vol 121 (1) ◽  
pp. 89-95 ◽  
Author(s):  
D. S. Crocker ◽  
D. Nickolaus ◽  
C. E. Smith
Keyword(s):  
Gas Turbine ◽  
Coupled Model ◽  
Design Tool ◽  
Cfd Modeling ◽  
Gas Turbine Combustor ◽  
Strongly Coupled ◽  
Gas Radiation ◽  
Cfd Models ◽  
Turbine Inlet ◽  
Combustor Liner

Gas turbine combustor CFD modeling has become an important combustor design tool in the past few years, but CFD models are generally limited to the flow field inside the combustor liner or the diffuser/combustor annulus region. Although strongly coupled in reality, the two regions have rarely been coupled in CFD modeling. A CFD calculation for a full model combustor from compressor diffuser exit to turbine inlet is described. The coupled model accomplishes the following two main objectives: (1) implicit description of flow splits and flow conditions for openings into the combustor liner, and (2) prediction of liner wall temperatures. Conjugate heat transfer with nonluminous gas radiation (appropriate for lean, low emission combustors) is utilized to predict wall temperatures compared to the conventional approach of predicting only near wall gas temperatures. Remaining difficult issues such as generating the grid, modeling Swirled vane passages, and modeling effusion cooling are also discussed.

Analysis of electrical conductivity measurements in strongly coupled tungsten and aluminum plasmas

2006 ◽  
Vol 56 (S2) ◽  
pp. B419-B424 ◽  
Author(s):  
S. I. Tkachenko ◽  
P. R. Levashov ◽  
K. V. Khishchenko
Keyword(s):  
Electrical Conductivity ◽  
Conductivity Measurements ◽  
Strongly Coupled
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