Transient response of the ‘multiple water-bag’ plasma

1989 ◽  
Vol 421 (1860) ◽  
pp. 109-152 ◽  
Keyword(s):  
Large Time ◽  
Transient State ◽  
Dispersion Curves ◽  
Kelvin Waves ◽  
Thermal Front ◽  
Transient Problem ◽  
Warm Plasma ◽  
A Charge ◽  
Response Field ◽  
State Feature

A charge activates impulsively and then decays temporally within a MWB (multiple water-bag)-modelled warm plasma. The transient problem is formulated and asymptotically resolved for large time. The response potential comprises two characteristically distinct quantities W and W N : W is a superposition of spherically expanding, moderately attenuated Kelvin waves contributed by certain points on a subset of dispersion curves; W N is a superposition, associated with two other dispersion curves, of three spherical wavefunctions, one of which incorporates the Fresnel integrals. A transient state feature of the MWB discretization is the partitioning of the response field by growing (fast) fronts, (trailing) slow caustics and a j¯ , the fastest among these being an a N¯ surface (thermal front) which pushes back a quasi-static exterior. Contrary to expectations, there is no response jump across any of those growing partitions. Wavefunctions near the slow caustics possess Airy factors. A rest state ultimately develops behind the slowest slow caustic. An application is made to the fluid plasma.

Design and Application of Fuzzy Controller

2011 ◽  
Vol 464 ◽  
pp. 107-110 ◽  
Author(s):  
Wei Zhang ◽  
Xue Yong Li ◽  
Li Li ◽  
Jing Qiao Lv ◽  
Yan Feng Chen ◽  
...  
Keyword(s):  
Pid Controller ◽  
Large Time ◽  
Fuzzy Controller ◽  
Transient State ◽  
Pi Controller ◽  
Steam Temperature ◽  
Analysis And Design ◽  
Highly Nonlinear ◽  
Fuzzy Logic Method ◽  
Fuzzy Pi Controller

The steam temperature of the boiler is one of the important parameters in the power plant, and it is necessary to keep the temperature at a steady range. For the traditional PID controller, which is suitable for the analysis and design of the linear system, is unfit for the control of the steam temperature of the boiler, since it’s a nonlinear system where exists large time delay. To address this kind of problem, we combine the traditional PID method with the fuzzy logic method to construct a compound fuzzy PI controller in order to improve the performances in both steady state and transient state of the classical PID controller when highly nonlinear processes and better control performances have been arrived at.

Steady-state and transient-state optical properties of a charge-transfer composite material MO-PPV/SWNTs

2008 ◽  
Vol 451 (1-3) ◽  
pp. 116-120 ◽  
Author(s):  
Saisai Chu ◽  
Wenhui Yi ◽  
Shufeng Wang ◽  
Fengming Li ◽  
Wenke Feng ◽  
...  
Keyword(s):  
Composite Material ◽  
Optical Properties ◽  
Charge Transfer ◽  
Steady State ◽  
Transient State ◽  
A Charge

scholarly journals Properties of lower hybrid waves

2008 ◽  
Vol 4 (S257) ◽  
pp. 569-573 ◽  
Author(s):  
Alix L. Verdon ◽  
I. H. Cairns ◽  
D. B. Melrose ◽  
P. A. Robinson
Keyword(s):  
Dispersion Relation ◽  
Dispersion Curves ◽  
Numerical Dispersion ◽  
Lower Hybrid ◽  
Plasma Parameters ◽  
Plasma Effects ◽  
Warm Plasma ◽  
Hybrid Waves ◽  
Lower Hybrid Waves ◽  
Good Agreement

AbstractMost treatments of lower hybrid waves include either electromagnetic or warm-plasma effects, but not both. Here we compare numerical dispersion curves for lower hybrid waves with a new analytic dispersion relation that includes both warm and electromagnetic effects. Very good agreement is obtained over significant ranges in wavenumber and plasma parameters, except where ion magnetization effects become important.

Planetary (Rossby), Inertia-Gravity (Poincaré) and Kelvin waves on the f-plane and β-plane in the presence of a uniform zonal flow

2021 ◽  
Author(s):  
Yair De-Leon ◽  
Chaim I. Garfinkel ◽  
Nathan Paldor
Keyword(s):  
Numerical Solutions ◽  
Bottom Topography ◽  
Phase Speed ◽  
Zonal Flow ◽  
Dispersion Curves ◽  
Kelvin Waves ◽  
Linear Wave ◽  
Hermite Function ◽  
Mean Flow ◽  
Zonal Wavenumber

<p>A linear wave theory of the Rotating Shallow Water Equations (RSWE) is developed in a channel on either the mid-latitude f-plane/β-plane or on the equatorial β-plane in the presence of a uniform mean zonal flow that is balanced geostrophically by a meridional gradient of the fluid surface height. We show that this surface height gradient is a potential vorticity (PV) source that generates Rossby waves even on the f-plane similar to the generation of these waves by PV sources such as the β–effect, shear of the mean flow and bottom topography. Numerical solutions of the RSWE show that the resulting planetary (Rossby), Inertia-Gravity (Poincaré) and Kelvin-like waves differ from their counterparts without mean flow in both their phase speeds and meridional structures. Doppler shifting of the “no mean-flow” phase speeds does not account for the difference in phase speeds, and the meridional structure does not often oscillate across the channel but is trapped near one the channel's boundaries in mid latitudes or behaves as Hermite function in the case of an equatorial channel. The phase speed of Kelvin-like waves is modified by the presence of a mean flow compared to the classical gravity wave speed but their meridional velocity does not vanish. The gaps between the dispersion curves of adjacent Poincaré modes are not uniform but change with the zonal wavenumber, and the convexity of the dispersion curves also changes with the zonal wavenumber. In some cases, the Kelvin-like dispersion curve crosses those of Poincaré modes, but it is not an evidence for the existence of instability since the Kelvin waves are not part of the solutions of an eigenvalue problem. </p>

Analyzing reactions of single mechanoenzyme molecules by light microscopy

1992 ◽  
Vol 50 (1) ◽  
pp. 426-427
Author(s):  
Jeff Gelles
Keyword(s):  
Image Processing ◽  
Reaction Mechanisms ◽  
Transient State ◽  
Nanometer Scale ◽  
Reaction Intermediates ◽  
Enzyme Molecule ◽  
Directed Movement ◽  
Enzyme Molecules ◽  
Individual Enzyme ◽  
Single Reaction

Mechanoenzymes are enzymes which use a chemical reaction to power directed movement along biological polymer. Such enzymes include the cytoskeletal motors (e.g., myosins, dyneins, and kinesins) as well as nucleic acid polymerases and helicases. A single catalytic turnover of a mechanoenzyme moves the enzyme molecule along the polymer a distance on the order of 10−9 m We have developed light microscope and digital image processing methods to detect and measure nanometer-scale motions driven by single mechanoenzyme molecules. These techniques enable one to monitor the occurrence of single reaction steps and to measure the lifetimes of reaction intermediates in individual enzyme molecules. This information can be used to elucidate reaction mechanisms and determine microscopic rate constants. Such an approach circumvents difficulties encountered in the use of traditional transient-state kinetics techniques to examine mechanoenzyme reaction mechanisms.

Drivers of diversity gradients of a highly mobile marine assemblage in a mesoscale seascape

2020 ◽  
Vol 638 ◽  
pp. 149-164
Author(s):  
GM Svendsen ◽  
M Ocampo Reinaldo ◽  
MA Romero ◽  
G Williams ◽  
A Magurran ◽  
...  
Keyword(s):  
Environmental Gradients ◽  
Regression Tree ◽  
Demersal Fish ◽  
Open Ocean ◽  
Shared Resources ◽  
Thermal Front ◽  
Boosted Regression Tree ◽  
Diversity Gradients ◽  
Α Diversity ◽  
Bottom Depth

With the unprecedented rate of biodiversity change in the world today, understanding how diversity gradients are maintained at mesoscales is a key challenge. Drawing on information provided by 3 comprehensive fishery surveys (conducted in different years but in the same season and with the same sampling design), we used boosted regression tree (BRT) models in order to relate spatial patterns of α-diversity in a demersal fish assemblage to environmental variables in the San Matias Gulf (Patagonia, Argentina). We found that, over a 4 yr period, persistent diversity gradients of species richness and probability of an interspecific encounter (PIE) were shaped by 3 main environmental gradients: bottom depth, connectivity with the open ocean, and proximity to a thermal front. The 2 main patterns we observed were: a monotonic increase in PIE with proximity to fronts, which had a stronger effect at greater depths; and an increase in PIE when closer to the open ocean (a ‘bay effect’ pattern). The originality of this work resides on the identification of high-resolution gradients in local, demersal assemblages driven by static and dynamic environmental gradients in a mesoscale seascape. The maintenance of environmental gradients, specifically those associated with shared resources and connectivity with an open system, may be key to understanding community stability.

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