scholarly journals Number of solitons produced from a large initial pulse in the generalized NLS dispersive hydrodynamics theory

2021 ◽  
Vol 104 (5) ◽  
Author(s):  
L. F. Calazans de Brito ◽  
A. M. Kamchatnov
Keyword(s):  
Initial Pulse

On the evolution of a nonlinear Alfvén pulse

1999 ◽  
Vol 62 (2) ◽  
pp. 219-232 ◽  
Author(s):  
E. VERWICHTE ◽  
V. M. NAKARIAKOV ◽  
A. W. LONGBOTTOM
Keyword(s):  
Temporal Evolution ◽  
Transverse Velocity ◽  
Longitudinal Velocity ◽  
Initial Pulse ◽  
Weakly Nonlinear ◽  
Starting Position ◽  
Linearly Polarized ◽  
Nonlinear Plane ◽  
The Magnetic Field ◽  
Good Agreement

The temporal evolution of weakly nonlinear, plane, linearly polarized Alfvén pulses in a cold homogeneous plasma is investigated. A static initial pulse-like disturbance in transverse velocity produces two Alfvén pulses that travel in opposite directions along the magnetic field. The ponderomotive force of the two pulses produces a static shock in longitudinal velocity at the starting position. The travelling pulses form a shock front that is governed by the scalar Cohen–Kulsrud equation. We find good agreement between the analytical solutions we derive and the results from a fully nonlinear numerical MHD code.

Reaction of shallow onshore waters to ground shock

1972 ◽  
Vol 62 (6) ◽  
pp. 1543-1557
Author(s):  
M. L. Merritt
Keyword(s):  
Time History ◽  
Free Fall ◽  
Full Time ◽  
Initial Pulse ◽  
Wave Shape ◽  
Ground Shock ◽  
Impact Shock

abstract Pressures and accelerations were measured in and near numerous ponds and lakes in Amchitka during the nuclear shot CANNIKIN, using peak measuring and full time-history recording instruments. The resulting pressures and accelerations were similar in wave shape: each showed an initial pulse, a period of free fall during spall, and an impact shock. It is found that when reverberation times in the water are short compared to rise times and other characteristic times of the ground shock, the water responds as a whole, and the pressure in it is proportional to the acceleration. When reverberation times are longer than rise times, pressure overshoots and oscillates about the simple proportionality.

Effects of β-Adrenoreceptor Antagonists on Sino-Aortic Baroreflex Sensitivity and Blood Pressure in Hypertensive Man

1979 ◽  
Vol 57 (3) ◽  
pp. 241-247 ◽  
Author(s):  
R. D. S. Watson ◽  
T. J. Stallard ◽  
W. A. Littler
Keyword(s):  
Blood Pressure ◽  
Essential Hypertension ◽  
Older Patients ◽  
Acute Treatment ◽  
Baroreflex Sensitivity ◽  
Chronic Treatment ◽  
Positive Relationship ◽  
Initial Pulse ◽  
Arterial Blood ◽  
Before And After

1. Sensitivity of the sino-aortic baroreflex was investigated before and after acute (23 patients) and chronic (23 patients) β-adrenoreceptor antagonism in patients with essential hypertension. 2. Sensitivity was inversely related to age (r = −0·60) and systolic blood pressure (r = −0·46); a positive relationship was noted between sensitivity and initial pulse intervals (r = 0·40). 3. Sensitivity increased significantly in patients less than 40 years of age after chronic treatment. No change occurred after acute treatment or in older patients treated chronically. 4. The fall in ambulatory intra-arterial blood pressure after chronic treatment was unrelated to alteration of baroreflex sensitivity.

CARDIOVASCULAR EFFECTS OF PENTOLINIUM BITARTRATE IN DOGS

1956 ◽  
Vol 34 (4) ◽  
pp. 747-755 ◽  
Author(s):  
W. E. G. A. Spoerel ◽  
C. W. Gowdey
Keyword(s):  
Pulse Rate ◽  
Acute Hypoxia ◽  
Peripheral Resistance ◽  
Cardiovascular Effects ◽  
Cardiovascular Responses ◽  
Minute Volume ◽  
Initial Pulse ◽  
Pressor Responses ◽  
Pulmonary Arterial ◽  
Sinus Pressure

Pentolinium (5 mgm./kgm.) injected intravenously into dogs anesthetized with pentobarbital caused the pulse rate to approach that of dogs with surgical cardiac denervation. The higher the initial pulse rate, the greater the decrease after the drug; rates under 100/min. were increased. Changes in arterial pressure followed a similar pattern, and the changes in both systemic and pulmonary arterial pressures were correlated with the changes in pulse rate. The cardiac output was decreased. Pressor responses to injected adrenaline and noradrenaline were greater after pentolinium. Total peripheral resistance, respiratory rate, respiratory minute volume, and oxygen consumption were not changed significantly, but local (hind-leg) resistance was decreased in two of three experiments. Pentolinium abolished or reduced markedly the cardiovascular responses to reduced carotid sinus pressure, tilting, acute hypoxia, large doses of acetylcholine, and hemorrhage. The cardiac vagus and the cardiovascular part of the sympathetic nervous system are blocked, but the experiments suggest that the adrenal medulla may not be completely blocked by 5 mgm./kgm. pentolinium.

scholarly journals Reaerosolization of Fluidized Spores in Ventilation Systems

2007 ◽  
Vol 73 (7) ◽  
pp. 2165-2172 ◽  
Author(s):  
Paula Krauter ◽  
Arthur Biermann
Keyword(s):  
High Efficiency ◽  
Initial Pulse ◽  
Bacillus Atrophaeus ◽  
Short Term ◽  
Indoor Airflow ◽  
Air Volume ◽  
Pulsed Flow ◽  
Air Intake ◽  
Turbulent Airflow

ABSTRACT This project examined dry, fluidized spore reaerosolization in a heating, ventilating, and air conditioning duct system. Experiments using spores of Bacillus atrophaeus, a nonpathogenic surrogate for Bacillus anthracis, were conducted to delineate the extent of spore reaerosolization behavior under normal indoor airflow conditions. Short-term (five air-volume exchanges), long-term (up to 21,000 air-volume exchanges), and cycled (on-off) reaerosolization tests were conducted using two common duct materials. Spores were released into the test apparatus in turbulent airflow (Reynolds number, 26,000). After the initial pulse of spores (approximately 1010 to 1011 viable spores) was released, high-efficiency particulate air filters were added to the air intake. Airflow was again used to perturb the spores that had previously deposited onto the duct. Resuspension rates on both steel and plastic duct materials were between 10−3 and 10−5 per second, which decreased to 10 times less than initial rates within 30 min. Pulsed flow caused an initial spike in spore resuspension concentration that rapidly decreased. The resuspension rates were greater than those predicted by resuspension models for contamination in the environment, a result attributed to surface roughness differences. There was no difference between spore reaerosolization from metal and that from plastic duct surfaces over 5 hours of constant airflow. The spores that deposited onto the duct remained a persistent source of contamination over a period of several hours.

scholarly journals The dispersion of a light pulse by a prism

1914 ◽  
Vol 90 (618) ◽  
pp. 298-312
Keyword(s):  
Energy Distribution ◽  
General Expression ◽  
Light Pulse ◽  
Focal Plane ◽  
Definite Function ◽  
Initial Pulse ◽  
Initial Form ◽  
First Time

This investigation is a continuation of a former one in which an expression was derived for a light pulse with an energy distribution given by Wien's law. The first three paragraphs are supplementary to the former paper; the rest of the investigation deals with the passage of the same pulse through a prism and its separation into the different colours in the focal plane of a telescope. The general principles according to which this must take place are, of course, known, but here the actual disturbance at every point in the focal plane is given for the first time as a definite function of the time and as a result it is possible to state how many waves there are in the trains, which the single initial pulse gives rise to in the various parts of the spectrum. §1. My general expression for the initial form of a light pulse was cos ( n + ½) θ /( x 2 + h 2 ) (2 n +1)/4 , where tan θ = x/h . I did no notice until after the former paper was communicated, that this expression is 1/Г ( n + ½) ∫ ∞ 0 e - ha cos αx α n -½ dα .

Temporal Alfvén wave echoes in an inhomogeneous plasma

1984 ◽  
Vol 31 (3) ◽  
pp. 395-414 ◽  
Author(s):  
I. C. Rae
Keyword(s):  
Surface Wave ◽  
Plasma Sheet ◽  
Inhomogeneous Plasma ◽  
Nonlinear Effects ◽  
Alfven Wave ◽  
Surface Phase ◽  
Initial Pulse ◽  
External Current ◽  
First Order ◽  
Resonance Surface

If an external current pulse is applied to a diffuse plasma sheet pinch, surface wave modes are generated, which decay by collisionless damping, leaving only oscillations of the Alfvén continuum along the Alfvén resonance surface. The transverse perturbations within this surface phase-mix to zero. It is shown that perturbations induced by an initial pulse are modulated by a (later applied) second pulse of different wavelength, to yield non-vanishing second-order transverse perturbations, even though the first-order transverse perturbations have phase-mixed to zero. This analysis shows the importance of nonlinear effects in the evolution of inhomogeneous magnetohydrodynamic motions.

Fabrication and Characterization of 4H-SiC 6kV Gate Turn-Off Thyristor

2012 ◽  
Vol 717-720 ◽  
pp. 1163-1166 ◽  
Author(s):  
Lei Lin ◽  
Jian Hui Zhao
Keyword(s):  
High Current Density ◽  
High Current ◽  
Initial Pulse ◽  
Large Area ◽  
Low Leakage ◽  
Low Leakage Current ◽  
Pulse Testing ◽  
Blocking Voltage ◽  
Fabrication And Characterization

In this paper, we report a 0.1cm2 4H-SiC gate-turn-off (GTO) thyristor with 6 kV blocking voltage fabricated on a structure with a 60µm blocking layer. A relatively large area, high voltage 4H-SiC GTO that exhibits encouraging characteristic at the on- and off-states, and a low leakage current with 63% devices blocking 3kV or higher. Initial pulse testing result shows that the fabricated GTOs are capable of both high current density and high turn-off speed.

scholarly journals Adsorption, Mobility, and Filtration of Metolachlor in Container Media

1996 ◽  
Vol 121 (3) ◽  
pp. 478-482 ◽  
Author(s):  
Timothy L. Grey ◽  
Glenn R. Wehtje ◽  
Ben F. Hajek ◽  
Charles H. Gilliam ◽  
Gary J. Keever ◽  
...  
Keyword(s):  
Laboratory Experiments ◽  
Pine Bark ◽  
Organic Media ◽  
Equilibration Time ◽  
Initial Pulse ◽  
Media Type ◽  
Freundlich Equation ◽  
Exposure Experiment ◽  
The Media ◽  
Glass Columns

Adsorption, mobility, and filtration ability of organic media toward metolachlor were evaluated in a series of laboratory experiments. Experimental variables included media type, metolachlor concentration, and equilibration time. Adsorption isotherms were determined by applying the log form of the Freundlich equation. Mobility was evaluated using glass columns filled with media, which were then surface spiked with metolachlor and then leached daily for 10 consecutive days. Peat, pine bark, combinations of these two media and a mixture of pine bark and sand adsorbed >90% of the 14C metolachlor. Freundlich sorption coefficients were 10.9, 18.2, 13.4, 14.2, and 11.0 for pine bark, peat, 5 pine bark: 1 peat, 3 pine bark: 1 peat, and 5 pine bark: 1 sand, respectively. In a timed exposure experiment using bark, minimum metolachlor adsorption (57%) was at 90 seconds and maximum adsorption (82%) required at least 1440 minutes. In column leaching studies, data for all media indicate that metolachlor is relatively immobile through these substrates. An initial pulse of metolachlor (<1.0 μg·liter-1) was detected with each medium up to the third wetting event with a subsequent decline (>0.5 μg·liter-1 for each medium) in the metolachlor recovered. Filtration efficiency of commercially formulated metolachlor from water passed through different lengths of pine bark filled filters was 0%, 17%, 20%, 22%, 23%, and 29% for filters 4, 20, 12, 8, 16, and 24 cm in length, respectively. These results support the contention that such filtration would be effective provided the residence time of water within the filter was sufficient for adsorption of the contaminant by the media to occur.

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