Journal articles on the topic 'Propagating'
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KAMIYAMA, KYOHEI, and TETSURO ENDO. "CHAOS OF THE PROPAGATING PULSE WAVE IN A RING OF SIX-COUPLED BISTABLE OSCILLATORS." International Journal of Bifurcation and Chaos 22, no. 04 (April 2012): 1250091. http://dx.doi.org/10.1142/s0218127412500915.
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In this paper, some properties of the chaotic propagating pulse wave in a ring of six-coupled bistable oscillators are investigated. When coupling factor α becomes large beyond a certain critical value, the standing pulse wave converts to a propagating pulse wave. Further, as α is increased, the propagating pulse wave behaves chaotically. We find some interesting properties of the chaotic propagating pulse wave such as random change of propagating direction and stepwise change of pulse position with respect to time. In particular, we notice that the shape of probability density of one-direction propagation time and distance is similar to that of Logistic map.
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Cheng, Yifeng, Lu Wang, and Tim Li. "Causes of Interdecadal Increase in the Intraseasonal Rainfall Variability over Southern China around the Early 1990s." Journal of Climate 33, no. 21 (November 1, 2020): 9481–96. http://dx.doi.org/10.1175/jcli-d-20-0047.1.
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AbstractThe southern China (SC) summer rainfall exhibits prominent intraseasonal variability, which exhibits a significant increase in the early 1990s with the turning point at 1993. The SC intraseasonal rainfall events could be divided into three categories according to different propagations, including the southward-propagating (SP) events, the northwestward-propagating (NWP) events, and the northward-propagating (NP) events. This study explores the causes of the observed interdecadal increase in the intraseasonal rainfall variability over SC by comparing the SC intraseasonal rainfall events of each category between the former decadal period (P1) and the later decadal period (P2). The result indicates that such interdecadal change is due to the more frequent NP events coming from the South China Sea (SCS). Based on the moisture and vorticity budget analysis, it is revealed that the summer mean southerly wind in the middle to lower troposphere is the dominant factor of the northward propagation over the SCS, as it could induce positive meridional moisture and vorticity advection anomalies ahead of the convection. A marked interdecadal enhancement of the summer mean southerly wind over the SCS is the cause of more frequent occurrence of NP events over SC, as it provides more favorable conditions for the northward propagation. The change of the atmospheric instability over the SCS where the NP convection perturbation originates was also investigated, but no significant change was found.
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Ehrlein, H. J., M. Schemann, and M. L. Siegle. "Motor patterns of small intestine determined by closely spaced extraluminal transducers and videofluoroscopy." American Journal of Physiology-Gastrointestinal and Liver Physiology 253, no. 3 (September 1, 1987): G259—G267. http://dx.doi.org/10.1152/ajpgi.1987.253.3.g259.
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In the canine small intestine several simple (S) and complex (C) patterns of propulsive and nonpropulsive activities were found. The nonpropulsive activity consisted of 1) stationary individual contractions (S) and 2) stationary clusters of contractions (C). Patterns leading to aboral propulsion of luminal contents were 1) propagating contractions (S), 2) propagating power contractions (S), 3) phase III of the migrating motor complex (C), and 4) migrating clusters of contractions (C). The propagation velocities of the propulsive motor patterns differed markedly; they increased in the following order: phase III, migrating clustered contractions, propagating power contractions, propagating contractions. A retrograde transport of luminal contents was produced by two different activities: 1) retrograde propagating contractions (S) and 2) retrograde power contractions (S). They were accompanied with enterogastric reflux.
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Sinha, Bablu, and Brenda Topliss. "A Description of Interdecadal Time-Scale Propagating North Atlantic Sea Surface Temperature Anomalies and Their Effect on Winter European Climate, 1948–2002." Journal of Climate 19, no. 7 (April 1, 2006): 1067–79. http://dx.doi.org/10.1175/jcli3646.1.
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Abstract Eastward-propagating interdecadal time-scale sea surface temperature (SST) winter anomalies have been shown to exist at the North Atlantic subpolar/subtropical gyre boundary. Heat flux and surface air temperature signatures of these anomalies are investigated using satellite- and ship-based SST observations and atmospheric reanalysis. Using bandpass filter analysis, retaining periods between 9 and 25 yr, a succession of coherent propagating SST anomalies is identified. The size, speed, propagation path, and decay characteristics of propagating anomalies detected during the period 1948–2002 are documented. The behavior of the propagations changes between the periods 1948–70 and 1970–2002. In the former period, SST anomalies propagated from the east coast of North America to the British Isles in ∼10 yr. The anomalies displayed a well-defined life cycle, growing in the western basin (west of 40°W) and decaying in the eastern basin. During the period 1970–2002, SST anomalies did not propagate deep into the eastern basin, but grew in the western basin and then ceased propagating. Oceanic anomalies have a comparable marked signature in surface sensible and latent heat fluxes and in surface air temperature. Winter surface heat flux anomalies act to amplify SST anomalies during the middle of their lifetimes, normally in the west-central Atlantic. At other times, heat flux anomalies are associated with decay of anomalies. Surface heat fluxes do not always act to cause propagation, and it is likely that other processes such as advection play a role in the propagation mechanism. North European winter surface air temperatures are raised or lowered by up to ±0.5°C over decadal time scales (∼1/3 of the total variation over the United Kingdom) when an SST anomaly reaches the eastern boundary. A variety of processes can cause SST variation on decadal time scales at the eastern boundary, but in the 1950s and 1960s the variability at these periods was the signature of features that had propagated across the Atlantic from the North American coast.
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Kim, Hyo Jin, Sang Ho Lee, and Moon Kyum Kim. "Prediction of Crack Propagation under Dynamic Loading Conditions by Using the Enhanced Point Collocation Meshfree Method." Key Engineering Materials 324-325 (November 2006): 1059–62. http://dx.doi.org/10.4028/www.scientific.net/kem.324-325.1059.
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An efficient and accurate numerical program with enhanced point collocation meshfree method is developed to simulate crack propagation under dynamic loading conditions. The enhanced meshfree method with point collocation formulation and derivative approximation in solids is presented. This study also presents the crack propagation criterion and computation of propagating direction, and the total structure of the numerical program named PCMDYC(Point Collocation Meshfree method for DYnamic Crack propagation). Several examples of crack propagation under dynamic loads are analyzed to simulate the arbitrary crack propagation under dynamic loads. The results show that PCMDYC predicts the propagating path of crack under dynamic loading conditions accurately and robustly.
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EZQUERRO, J. M., G. HERNÁNDEZ, M. NOMBELA, OSCAR G. CALDERÓN, and SONIA MELLE. "FAST LIGHT ENHANCEMENT BY BIDIRECTIONAL PUMPING IN ERBIUM-DOPED FIBERS." Journal of Nonlinear Optical Physics & Materials 19, no. 01 (March 2010): 153–65. http://dx.doi.org/10.1142/s021886351000498x.
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We analyze the effect of pump configuration on the propagation velocity of an amplitude-modulated 1536 nm signal propagating through an ultra-highly doped erbium fiber amplifier. The nonlinear effects arising from the high value of the doping level lead to a strong variation of the pump power and signal gain along the fiber. We found that bidirectional pumping presents larger advancements than co-propagating and counter-propagating configurations. Numerical simulations allow us to explain the phenomenon in terms of the gain profile uniformity.
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Dan, Wensong, Xiang Zang, Fei Wang, Yimin Zhou, Yiqing Xu, Ruipin Chen, and Guoquan Zhou. "Interference enhancement effect in a single Airyprime beam propagating in free space." Optics Express 30, no. 18 (August 22, 2022): 32704. http://dx.doi.org/10.1364/oe.469593.
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An analytical expression of a single Airyprime beam propagating in free space is derived. Upon propagation in free space, a single Airyprime beam in arbitrary transverse direction is the coherent superposition of the Airyprime and the Airy-related modes, which results in the interference enhancement effect under the appropriate condition. The Airy-related mode is the conventional propagating Airy mode with an additional π/2 phase shift and a weight coefficient of half the normalized propagation distance. Due to the peak light intensity in the initial plane being set to be 1, the strength of interference enhancement effect is characterized by the maximum light intensity. The maximum light intensity of a single Airyprime beam propagating in free space is independent of the scaling factor and is only decided by the exponential decay factor. When the exponential decay factor is above the saturated value, the interference enhancement effect disappears. When the exponential decay factor decreases from the saturated value, the maximum light intensity of a single propagating Airyprime beam increases, and the position of maximum light intensity is getting farther away. With the increase of the scaling factor, the position of maximum light intensity of a single propagating Airyprime beam is extended. The intensity distribution and the transverse Poynting vector of a single propagating Airyprime beam are demonstrated in different observation planes of free space. The flow direction of transverse energy flux effectively supports the interference enhancement effect of a single propagating Airyprime beam. The Airyprime beam is experimentally generated, and the interference enhancement effect is experimentally confirmed. The interference enhancement effect is conducive to the practical application of a single Airyprime beam.
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Sellitto, Antonio, Patrizia Rogolino, and Isabella Carlomagno. "Heat-pulse propagation along nonequilibrium nanowires in thermomass theory." Communications in Applied and Industrial Mathematics 7, no. 2 (June 1, 2016): 39–55. http://dx.doi.org/10.1515/caim-2016-0005.
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AbstractWe analyze the consequences of the nonlinear terms in the heat-transport equation of the thermomass theory on heat pulses propagating in a nanowire in nonequilibrium situations. As a consequence of the temperature dependence of the speeds of propagation, in temperature ranges wherein the specific heat shows negligible variations, heat pulses will shrink (or extend) spatially, and will increase (or decrease) their average temperature when propagating along a temperature gradient. A comparison with the results predicted by a different theoretical proposal on the shape of a propagating heat pulse is made, too.
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Lin, Anthony Y., Peng Du, Philip G. Dinning, John W. Arkwright, Jozef P. Kamp, Leo K. Cheng, Ian P. Bissett, and Gregory O'Grady. "High-resolution anatomic correlation of cyclic motor patterns in the human colon: Evidence of a rectosigmoid brake." American Journal of Physiology-Gastrointestinal and Liver Physiology 312, no. 5 (May 1, 2017): G508—G515. http://dx.doi.org/10.1152/ajpgi.00021.2017.
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Colonic cyclic motor patterns (CMPs) have been hypothesized to act as a brake to limit rectal filling. However, the spatiotemporal profile of CMPs, including anatomic origins and distributions, remains unclear. This study characterized colonic CMPs using high-resolution (HR) manometry (72 sensors, 1-cm resolution) and their relationship with proximal antegrade propagating events. Nine healthy volunteers were recruited. Recordings were performed over 4 h, with a 700-kcal meal given after 2 h. Propagating events were visually identified and analyzed by pattern, origin, amplitude, extent of propagation, velocity, and duration. Manometric data were normalized using anatomic landmarks identified on abdominal radiographs. These were mapped over a three-dimensional anatomic model. CMPs comprised a majority of detected propagating events. Most occurred postprandially and were retrograde propagating events (84.9 ± 26.0 retrograde vs. 14.3 ± 11.8 antegrade events/2 h, P = 0.004). The dominant sites of initiation for retrograde CMPs were in the rectosigmoid region, with patterns proximally propagating by a mean distance of 12.4 ± 0.3 cm. There were significant differences in the characteristics of CMPs depending on the direction of travel and site of initiation. Association analysis showed that proximal antegrade propagating events occurred independently of CMPs. This study accurately characterized CMPs with anatomic correlation. CMPs were unlikely to be triggered by proximal antegrade propagating events in our study context. However, the distal origin and prominence of retrograde CMPs could still act as a mechanism to limit rectal filling and support the theory of a “rectosigmoid brake.” NEW & NOTEWORTHY Retrograde cyclic motor patterns (CMPs) are the dominant motor patterns in a healthy prepared human colon. The major sites of initiation are in the rectosigmoid region, with retrograde propagation, supporting the idea of a “rectosigmoid brake.” A significant increase in the number of CMPs is seen after a meal. In our study context, the majority of CMPs occurred independent of proximal propagating events, suggesting that CMPs are primarily controlled by external innervation.
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ASLANIDI, O. V., and A. V. HOLDEN. "A SIMPLE MODEL FOR INTERACTION OF VOLTAGE AND CALCIUM DYNAMICS IN VIRTUAL VENTRICULAR TISSUE." International Journal of Bifurcation and Chaos 13, no. 12 (December 2003): 3873–86. http://dx.doi.org/10.1142/s0218127403008776.
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A simple two-variable model is used to replace the formulation of calcium dynamics in the Luo–Rudy ventricular cell model. Virtual ventricular cell and tissue are developed and validated to reproduce restitution properties and calcium-dependent voltage patterns present in the original model. Basic interactions between the membrane potential and Ca 2+ dynamics in the virtual cell and a strand of the virtual tissue are studied. Intracellular calcium waves can be linked to both action potentials (APs) and delayed afterdepolarizations (DADs). An intracellular calcium wave propagating from the cell interior can induce an AP upon reaching the cell membrane. The voltage and the intracellular Ca 2+ patterns within the same cell can be highly desynchronized. In a one-dimensional strand of the virtual tissue calcium motion is driven by the AP propagation. However, calcium release can be induced upon certain conditions (e.g. Na + overload of the cells), which results in DADs propagating in the wake of AP. Such propagating DADs can reach the excitation threshold, generating a pair of extrasystolic APs. Collision of a propagating AP with a site of elevated intracellular Ca 2+ concentration does not affect the propagation under the normal conditions. Under Na + overload local elevation of the intracellular Ca 2+ leads to generation of an extrasystolic AP, which destroys the original propagating AP.
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Aoki, Y., T. Matsuyama, Yasuji Oda, Kenji Higashida, and Hiroshi Noguchi. "Effects of Hydrogen Gas Environment on Non-Propagation Phenomena of a Type 304 Austenitic Stainless Steel." Key Engineering Materials 297-300 (November 2005): 927–32. http://dx.doi.org/10.4028/www.scientific.net/kem.297-300.927.
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In order to investigate the hydrogen gas effect on non-propagation phenomena of a type 304 austenitic stainless steel, fatigue tests with in-situ observation using a Scanning Laser Microscope were performed in air, in 0.18MPa hydrogen gas and in 0.18MPa nitrogen gas. A nonpropagating crack was observed during the fatigue test in air. At almost the same stress level of non-propagating in air, non-propagating cracks were also observed in fatigue tests in hydrogen and in nitrogen. Stress level of the non-propagation is not sufficiently different in the three environments. However, the process up to non-propagation differs from each other, for example, the crack path and debris.
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Jardon, Zoé, Michaël Hinderdael, Tamas Regert, Jeroen Van Beeck, and Patrick Guillaume. "On the Nature of Pressure Wave Propagation through Ducts for Structural Health Monitoring Application." Applied Sciences 9, no. 5 (February 26, 2019): 837. http://dx.doi.org/10.3390/app9050837.
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An effective structural health monitoring system fully exploits the flexibility offered by the 3D printing process by integrating a smart structural health monitoring technology inside the 3D-printed components. The system relies on the propagation of pressure waves with constant propagation speed through circular capillaries embedded in the structure. The nature of these waves seems to be determinant for the accuracy of the crack localization system. To achieve a better physical understanding of the nature of the propagating waves through the capillaries, computational fluid dynamics simulations are performed and compared to experimental results obtained with a self-built test setup. The presence of propagating shock waves is observed in the simulations and experiments, as well as a complex reflection mechanism around the leak location. Shock waves show the characteristic of not propagating at a constant velocity. This property complicates the actual localization system. To solve this, the constant velocity assumption should be replaced with the effective velocity evolution to increase the localization accuracy. The amplitude of the shock wave is attenuated with propagating distance, which proves that the effect of friction plays an important role and can, in turn, influence the localization system.
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Adewusi, S. A., and B. O. Al-Bedoor. "Experimental Study on the Vibration of an Overhung Rotor with a Propagating Transverse Crack." Shock and Vibration 9, no. 3 (2002): 91–104. http://dx.doi.org/10.1155/2002/405928.
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This paper presents an experimental study on the dynamic response of an overhung rotor with a propagating transverse crack. The effects of a propagating transverse crack and side load on the dynamic response of an overhung rotor are investigated in order to identify vibration signatures of a propagating crack in rotating shafts. Startup and steady state vibration signatures were analyzed and presented in the form of Bode plots, Frequency Spectrum Cascades, Frequency Spectrum Waterfalls and orbits. The startup results showed that crack reduces the critical speed and increases the vibration amplitude of the rotor system. It also excites 2X vibration in the startup vibration signatures. The steady state results showed that the propagating crack produces changes in vibration amplitudes of 1X and 2X vibration harmonics and excites 3X harmonic just before fracture. During crack propagation, 1X amplitude may increase or decrease depending on the location of the crack and the direction of vibration measurement while 2X amplitude always increases. The steady state vibration signal of a propagating crack also produces a two-loop orbit.
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CAMPOS, L. M. B. C., and P. M. V. M. MENDES. "On the effects of viscosity and anisotropic resistivity on the damping of Alfvén waves." Journal of Plasma Physics 63, no. 3 (April 2000): 221–38. http://dx.doi.org/10.1017/s0022377899008259.
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The equations of magnetohydrodynamics (MHD) are written for non-uniform viscosity and resistivity – the latter in the cases of Ohmic and anisotropic resistivity. In the case of Ohmic (anisotropic) diffusivity, there is (are) one (two) transverse components of the velocity and magnetic field perturbation(s), leading to a second-order (fourth-order) dissipative Alfvén- wave equation. In the more general case of dissipative Alfvén waves with isotropic viscosity and anisotropic resistivity, the fourth-order wave equation may be replaced by two decoupled second-order equations for right- and left-polarized waves, whose dispersion relations show that the first resistive diffusivity causes dissipation like the viscosity, whereas the second resistive diffusivity causes a change in propagation speed. The second resistive diffusivity invalidates the equipartition of kinetic and magnetic energy, modifies the energy flux through the propagation speed, and also changes the ratio of viscous to resistive dissipation. If the directions of propagation and polarization are equal (i.e. for right-polarized upward-propagating or left-polarized downward-propagating waves), the magnetic energy increases relative to the kinetic energy, the resistive dissipation increases relative to the viscous dissipation, and the total energy density and flux increase relative to the case of isotropic resistivity; the reverse is the case for opposite directions of propagation, i.e. upward-propagating left-polarized waves and downward-propagating right-polarized waves, which can lead to the existence of a critical layer. The role of the viscosity and first and second resistive diffusiveness on the dissipation of Alfvén waves is discussed with reference to the solar atmosphere.
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Sazhin, S. S. "Whistler-mode polarization in a hot anisotropic plasma." Journal of Plasma Physics 34, no. 2 (October 1985): 213–26. http://dx.doi.org/10.1017/s0022377800002804.
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Polarization of whistler-mode waves in a hot anisotropic plasma is considered in the two limiting cases of quasi-longitudinal and quasi-electrostatic propagation. It is pointed out that electron thermal motion never influences the phase of the propagating waves; the polarization of whistler-mode waves propagating along the magnetic field is totally independent of electron thermal motion. The deformation of polarization (in both electric and magnetic fields), of obliquely propagating whistler-mode waves could be, in principle, observed in magnetospheric conditions and thus could be used to estimate electron temperature and anisotropy. This deformation seems to be especially pronounced for the electric field polarization of quasi-electrostatic waves.
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Buller, A. S., Yu V. Zelenetskaya, R. V. Litvinov, and N. R. Melikhova. "Modulation instability of two TE modes in a thin left-handed film on a nonlinear right-handed substrate." Quantum Electronics 51, no. 11 (November 1, 2021): 1030–37. http://dx.doi.org/10.1070/qel17647.
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Abstract The intramode wave beams in a thin left-handed film on a Kerr substrate are considered at a frequency near zero mode group velocity. Four coupled (1 + 1)-dimensional nonlinear Schrödinger equations, describing the interaction of forward and backward propagating beams with positive and negative group velocities, are derived. It is shown that self- and cross-phase modulation for four simultaneously propagating modes is possible only at strictly matched perturbations of their propagation constants, which is due to the contribution of spatial parametric mixing. The modulation instability of only two waveguide modes is analysed for different versions of their propagation. The specific features of modulation instability, related to the propagation of modes with negative group velocities, are investigated.
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Feng, Hai Lin, Yi Ming Fang, Jian Li, and Guang Hui Li. "Using Stress Wave Based Technology for Wood Material Nondestructive Testing." Advanced Materials Research 143-144 (October 2010): 265–70. http://dx.doi.org/10.4028/www.scientific.net/amr.143-144.265.
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Stress wave based technology has its special advantages in the field of wood nondestructive testing and quality evaluation. To analysis the propagating properties of stress wave in the wood material, a transmitting model in anisotropic material was introduced in rectangular and cylindrical polar coordinate system. The relationship between stress wave propagation and elastic constants was shown. The propagating of stress wave in wood material and the possible solutions with different parameters were studied. The transmitting character of stress wave in symmetry planes was analyzed, and the elastic constants of woods were used to compute the stress wave propagation in wood material.
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Sciacca, Michele, and David Jou. "Nonlinear Thermal Transport with Inertia in Thin Wires: Thermal Fronts and Steady States." Journal of Non-Equilibrium Thermodynamics 47, no. 2 (March 31, 2022): 187–94. http://dx.doi.org/10.1515/jnet-2021-0069.
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Abstract In a series of papers we have obtained results for nonlinear heat transport when thin wires exchange heat non-linearly with the surroundings, with particular attention to propagating solitons. Here we obtain and discuss new results related to the propagation of nonlinear heat fronts and some conceptual aspects referring to the application of the second principle of thermodynamics to some nonlinear steady states related to non-propagating solitons.
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Whalley, Katherine. "Propagating pathology." Nature Reviews Neuroscience 15, no. 9 (July 30, 2014): 565. http://dx.doi.org/10.1038/nrn3802.
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Pawley, Ray. "PROPAGATING REPTILES." International Zoo Yearbook 4, no. 1 (December 18, 2007): 95–97. http://dx.doi.org/10.1111/j.1748-1090.1963.tb03635.x.
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Neugebauer, Marcia. "Propagating Shocks." Space Science Reviews 176, no. 1-4 (December 15, 2010): 125–32. http://dx.doi.org/10.1007/s11214-010-9707-2.
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Hudson, A., J. Critchley, and Y. Erasmus. "Propagating Antirrhinum." Cold Spring Harbor Protocols 2008, no. 11 (October 1, 2008): pdb.prot5052. http://dx.doi.org/10.1101/pdb.prot5052.
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Sherman, Dov, and Ilan Be'ery. "Shape and energies of a dynamically propagating crack under bending." Journal of Materials Research 18, no. 10 (October 2003): 2379–86. http://dx.doi.org/10.1557/jmr.2003.0333.
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We report on the exact shape of a propagating crack in a plate with a high width/thickness ratio and subjected to bending deformation. Fracture tests were carried out with brittle solids—single crystal, polycrystalline, and amorphous. The shape of the propagating crack was determined from direct temporal crack length measurements and from the surface perturbations generated during rapid crack propagation. The shape of the crack profile was shown to be quarter-elliptical with a straight, long tail; the governing parameter of the ellipse axes is the specimen's thickness at most length of crack propagation. Universality of the crack front shape is demonstrated. The continuum mechanics approach applicable to two-dimensional problems was used in this three-dimensional problem to calculate the quasistatic strain energy release rate of the propagating crack using the formulations of the dynamic energy release rate along the crack loci. Knowledge of the crack front shape in the current geometry and loading configuration is important for practical and scientific aspects.
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Wang, Yafei, Koji Yamazaki, and Yasushi Fujiyoshi. "The Interaction between Two Separate Propagations of Rossby Waves." Monthly Weather Review 135, no. 10 (October 1, 2007): 3521–40. http://dx.doi.org/10.1175/mwr3486.1.
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Abstract This study deals with two teleconnection patterns and the subsequent wave train propagations during an East Asian summer. Diagnostic results are as follows: 1) a stationary wave ray with zonal wavenumber 5 approximates the arc path linking the correlation centers originating from the Caspian Sea via Lake Baikal to the sea off the southeast coast of Japan (i.e., the OKJ arc path as a focus area) in a pentad correlation map between 500-hPa geopotential height (Z500) and outgoing longwave radiation (OLR) at 30°N, 150°E in June 1979–98. Ray tracing shows that it took 8–10 days for this stationary wave to propagate from an initial position around the Caspian Sea to the focus area, which roughly coincides with the observed case in July 1998. 2) A wave train pattern (P-Ja) observed in the boreal summer propagated along the arc line in the same way as the normal poleward Rossby wave train originating from the Philippines across the North Pacific (P-J), but with a phase shift northeastward of about 90°. 3) Further correlation analyses showed that the P-J-like waves belong mainly to intraseasonal propagating ones while OKJ waves belong mainly to intraseasonal stationary ones. 4) Propagation of the newly observed wave train pattern (P-Ja) occurred following another wave train along the OKJ arc path in mid-July 1998. Both northeastward and southeastward wave propagations merged off the east coast of Japan. 5) The northeastward-propagating wave train observed in mid-July 1998 was triggered by the southeastward-propagating (OKJ) wave train that produced a deep cyclonic circulation and a strong convective activity in the focus area. The link of wave forcing and deep convection was made solely because of a strong upper-level divergence in the focus area.
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Mied, Richard P., Arnold L. Cooper, Gloria J. Lindemann, and Mark A. Sletten. "Wave propagation along freely propagating surface gravity current fronts." Dynamics of Atmospheres and Oceans 36, no. 1-3 (November 2002): 59–81. http://dx.doi.org/10.1016/s0377-0265(02)00025-8.
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Pospíchal, Milan. "Quantum theory of light propagation III. Counter-propagating waves." Czechoslovak Journal of Physics 46, no. 5 (May 1996): 473–90. http://dx.doi.org/10.1007/bf01690895.
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Giletti, Thomas, and Hiroshi Matano. "Existence and uniqueness of propagating terraces." Communications in Contemporary Mathematics 22, no. 06 (June 17, 2019): 1950055. http://dx.doi.org/10.1142/s021919971950055x.
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This work focuses on dynamics arising from reaction-diffusion equations, where the profile of propagation is no longer characterized by a single front, but by a layer of several fronts which we call a propagating terrace. This means, intuitively, that transition from one equilibrium to another may occur in several steps, that is, successive phases between some intermediate stationary states. We establish a number of properties on such propagating terraces in a one-dimensional periodic environment under very wide and generic conditions. We are especially concerned with their existence, uniqueness, and their spatial structure. Our goal is to provide insight into the intricate dynamics arising from multistable nonlinearities.
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Wang, Bin, Guosen Chen, and Fei Liu. "Diversity of the Madden-Julian Oscillation." Science Advances 5, no. 7 (July 2019): eaax0220. http://dx.doi.org/10.1126/sciadv.aax0220.
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Madden-Julian Oscillation (MJO) is the dominant mode of atmospheric intraseasonal variability and the cornerstone for subseasonal prediction of extreme weather events. Climate modeling and prediction of MJO remain a big challenge, partially due to lack of understanding the MJO diversity. Here, we delineate observed MJO diversity by cluster analysis of propagation patterns of MJO events, which reveals four archetypes: standing, jumping, slow eastward propagation, and fast eastward propagation. Each type exhibits distinctive east-west asymmetric circulation and thermodynamic structures. Tight coupling between the Kelvin wave response and major convection is unique for the propagating events, while the strength and length of Kelvin wave response distinguish slow and fast propagations. The Pacific sea surface temperature anomalies can affect MJO diversity by modifying the Kelvin wave response and its coupling to MJO convection. The results shed light on the mechanisms responsible for MJO diversity and provide potential precursors for foreseeing MJO propagation.
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Hamabata, Hiromitsu, Tomikazu Namikawa, and Kazuhiro Mori. "The effect of lower-hybrid waves on the propagation of hydromagnetic waves." Journal of Plasma Physics 40, no. 2 (October 1988): 337–51. http://dx.doi.org/10.1017/s0022377800013313.
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Propagation characteristics of hydromagnetic waves in a magnetic plasma are investigated using the two-plasma fluid equations including the effect of lower-hybrid waves propagating perpendicularly to the magnetic field. The effect of lower-hybrid waves on the propagation of hydromagnetic waves is analysed in terms of phase speed, growth rate, refractive index, polarization and the amplitude relation between the density perturbation and the magnetic-field perturbation for the cases when hydromagnetic waves propagate in the plane whose normal is perpendicular to both the magnetic field and the propagation direction of lower-hybrid waves and in the plane perpendicular to the propagation direction of lower-hybrid waves. It is shown that hydromagnetic waves propagating at small angles to the propagation direction of lower-hybrid waves can be excited by the effect of lower-hybrid waves and the energy of excited waves propagates nearly parallel to the propagation direction of lower-hybrid waves.
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Cai, H. T., F. Yin, S. Y. Ma, and I. W. McCrea. "Observations of AGW/TID propagation across the polar cap: a case study." Annales Geophysicae 29, no. 8 (August 12, 2011): 1355–63. http://dx.doi.org/10.5194/angeo-29-1355-2011.
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Abstract. In this paper, we present observational evidence for the trans-polar propagation of large-scale Traveling Ionospheric Disturbances (TIDs) from their nightside source region to the dayside. On 13 February 2001, the 32 m dish of EISCAT Svalbard Radar (ESR) was directing toward the geomagnetic pole at low elevation (30°) during the interval 06:00–12:00 UT (MLT ≈ UT + 3 h), providing an excellent opportunity to monitor the ionosphere F-region over the polar cap. The TIDs were first detected by the ESR over the dayside north polar cap, propagating equatorward, and were subsequently seen by the mainland UHF radar at auroral latitudes around geomagnetic local noon. The propagation properties of the observed ionization waves suggest the presence of a moderately large-scale TIDs, propagating across the northern polar cap from the night-time auroral source during substorm conditions. Our results agree with the theoretical simulations by Balthazor and Moffett (1999) in which poleward-propagating large-scale traveling atmospheric disturbances were found to be self-consistently driven by enhancements in auroral heating.
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Gao, Tingran, Shahab Asoodeh, Yi Huang, and James Evans. "Wasserstein Soft Label Propagation on Hypergraphs: Algorithm and Generalization Error Bounds." Proceedings of the AAAI Conference on Artificial Intelligence 33 (July 17, 2019): 3630–37. http://dx.doi.org/10.1609/aaai.v33i01.33013630.
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Inspired by recent interests of developing machine learning and data mining algorithms on hypergraphs, we investigate in this paper the semi-supervised learning algorithm of propagating ”soft labels” (e.g. probability distributions, class membership scores) over hypergraphs, by means of optimal transportation. Borrowing insights from Wasserstein propagation on graphs [Solomon et al. 2014], we re-formulate the label propagation procedure as a message-passing algorithm, which renders itself naturally to a generalization applicable to hypergraphs through Wasserstein barycenters. Furthermore, in a PAC learning framework, we provide generalization error bounds for propagating one-dimensional distributions on graphs and hypergraphs using 2-Wasserstein distance, by establishing the algorithmic stability of the proposed semisupervised learning algorithm. These theoretical results also shed new lights upon deeper understandings of the Wasserstein propagation on graphs.
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Zhu, Jun, Hanhao Zhu, Jun Tang, and Guangxue Zheng. "Researches on very low frequency acoustic signal propagation characteristics in different shallow elastic wedge bottoms." MATEC Web of Conferences 283 (2019): 02003. http://dx.doi.org/10.1051/matecconf/201928302003.
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Targeted at the issue of extremely low-frequency (<100Hz) acoustic propagation in complex shallow elastic bottom environments. The influence law of different complex elastic bottoms on the acoustic signal propagation at very low frequency by acoustic energy flux has been analyzed with the simulation, which is based on the finite element method. The elastic bottoms which have been studied are the shallow horizontal elastic bottom, and the up-sloping and the down-sloping elastic bottom. The results show that the acoustic signal propagating in the up-sloping and down-sloping elastic bottom environments is more complex than that propagating in the horizontal elastic bottom, and the acoustic energy leaking into those elastic bottoms has very different influence on the acoustic signal propagation, especially in the up-sloping bottom.
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Wu, Renguang, and Ben P. Kirtman. "Near-Annual SST Variability in the Equatorial Pacific in a Coupled General Circulation Model." Journal of Climate 18, no. 21 (November 1, 2005): 4454–73. http://dx.doi.org/10.1175/jcli3536.1.
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Abstract Equatorial Pacific sea surface temperature (SST) anomalies in the Center for Ocean–Land–Atmosphere Studies (COLA) interactive ensemble coupled general circulation model show near-annual variability as well as biennial El Niño–Southern Oscillation (ENSO) variability. There are two types of near-annual modes: a westward propagating mode and a stationary mode. For the westward propagating near-annual mode, warm SST anomalies are generated in the eastern equatorial Pacific in boreal spring and propagate westward in boreal summer. Consistent westward propagation is seen in precipitation, surface wind, and ocean current. For the stationary near-annual mode, warm SST anomalies develop near the date line in boreal winter and decay locally in boreal spring. Westward propagation of warm SST anomalies also appears in the developing year of the biennial ENSO mode. However, warm SST anomalies for the westward propagating near-annual mode occur about two months earlier than those for the biennial ENSO mode and are quickly replaced by cold SST anomalies, whereas warm SST anomalies for the biennial ENSO mode only experience moderate weakening. Anomalous zonal advection contributes to the generation and westward propagation of warm SST anomalies for both the westward propagating near-annual mode and the biennial ENSO mode. However, the role of mean upwelling is markedly different. The mean upwelling term contributes to the generation of warm SST anomalies for the biennial ENSO mode, but is mainly a damping term for the westward propagating near-annual mode. The development of warm SST anomalies for the stationary near-annual mode is partially due to anomalous zonal advection and upwelling, similar to the amplification of warm SST anomalies in the equatorial central Pacific for the biennial ENSO mode. The mean upwelling term is negative in the eastern equatorial Pacific for the stationary near-annual mode, which is opposite to the ENSO mode. The development of cold SST anomalies in the aftermath of warm SST anomalies for the westward propagating near-annual mode is coupled to large easterly wind anomalies, which occur between the warm and cold SST anomalies. The easterly anomalies contribute to the cold SST anomalies through anomalous zonal, meridional, and vertical advection and surface evaporation. The cold SST anomalies, in turn, enhance the easterly anomalies through a Rossby-wave-type response. The above processes are most effective during boreal spring when the mean near-surface-layer ocean temperature gradient is the largest. It is suggested that the westward propagating near-annual mode is related to air–sea interaction processes that are limited to the near-surface layers.
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Boos, William R., and Zhiming Kuang. "Mechanisms of Poleward Propagating, Intraseasonal Convective Anomalies in Cloud System–Resolving Models." Journal of the Atmospheric Sciences 67, no. 11 (November 1, 2010): 3673–91. http://dx.doi.org/10.1175/2010jas3515.1.
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Abstract An envelope of convection that propagates both poleward and eastward accounts for the largest fraction of intraseasonal variance of the tropical atmosphere during boreal summer. Here the mechanisms of poleward propagating convective anomalies are examined in a nonhydrostatic model with zonally symmetric boundary conditions, integrated on a beta plane at resolutions high enough to explicitly represent moist convection. When the domain has a narrow zonal dimension of 100 km or less, the model produces a quasisteady intertropical convergence zone (ITCZ). Meridionally propagating transients are produced for some prescribed sea surface temperature distributions, but these transients are shallow, vanish at finer resolutions, and have a structure that bears little resemblance to that of observed poleward propagating anomalies. This is in sharp contrast to previous studies that obtained robust poleward propagating anomalies in axisymmetric models using parameterized moist convection, and it suggests that the anomalies seen in those models may be caused by deficient representations of dynamics or subgrid-scale physics. Robust poleward propagating anomalies are obtained when the high-resolution, nonhydrostatic model is integrated in a wider domain with a zonal dimension near 1000 km. Diagnostics suggest that poleward propagation in this wide domain results from the convectively coupled beta drift of low-level vorticity anomalies. Deep near-equatorial ascent produces low-level cyclones that migrate poleward through the process of beta drift; Ekman pumping in these drifting cyclones then humidifies the free troposphere ahead of the initial deep ascent, shifting the convection poleward. The moist static energy budget and model sensitivity tests suggest that these anomalies can be viewed as moisture modes destabilized through a moisture–radiation feedback. Wind–evaporation feedback also seems to contribute to the instability of these anomalies, but because it enhances surface fluxes on the equatorward side of the anomalies, it also reduces their propagation speed. These results suggest a novel mechanism for the poleward propagation of intraseasonal convective anomalies and illustrate the need to evaluate theoretical models that use parameterized convection against cloud system–resolving models.
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Cook, Ian J., Yoshiyuki Furukawa, Voula Panagopoulos, Peter J. Collins, and John Dent. "Relationships between spatial patterns of colonic pressure and individual movements of content." American Journal of Physiology-Gastrointestinal and Liver Physiology 278, no. 2 (February 1, 2000): G329—G341. http://dx.doi.org/10.1152/ajpgi.2000.278.2.g329.
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The aim of this study was to examine the relationship between colonic pressure waves and movement of content. In 11 healthy subjects, pressures were recorded at 10-cm intervals from cecum to rectum for 32 h. In six subjects, transit was simultaneously measured for 8 h after direct cecal instillation of 1.5 mCi of 99mTc sulfur colloid. Thirty-two percent of isotope movements were related to nonpropagating activity and twenty-eight percent to propagating sequences. The extent of isotope movement related to propagating sequences (25.1 ± 2.1 cm) was greater than that due to nonpropagating activity (12.8 ± 0.7 cm; P = 0.0001). Propagating sequences originated significantly more frequently ( P = 0.004) and propagated further ( P = 0.0006) in the proximal compared with the distal colon. Only 36% of propagating sequences were propulsive of content, and compared with nonpropulsive sequences, these propagated further (41 ± 6 vs. 27 ± 2 cm; P < 0.05) and had a higher probability of originating proximally ( P = 0.0003), a higher pressure wave amplitude (50 ± 5 vs. 34 ± 4 mmHg; P = 0.0001), and slower velocity (2.2 ± 0.3 vs. 3.6 ± 0.47 cm/s; P = 0.02). We conclude that most movements of colonic content are related to pressure waves. There is marked regional variation in the prevalence, velocity, and extent of propagation of propagating pressure wave sequences, which are an important mechanism for transporting content over long distances. The effectiveness of transport by a propagating sequence is influenced by its site of origin, amplitude, and velocity.
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Nuss, Wendell A. "Synoptic-Scale Structure and the Character of Coastally Trapped Wind Reversals." Monthly Weather Review 135, no. 1 (January 1, 2007): 60–81. http://dx.doi.org/10.1175/mwr3267.1.
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Abstract Coastally trapped wind reversals that occur along the U.S. West Coast have been described in numerous other studies. The synoptic-scale environment and the forcing of a coastally trapped Kelvin wave are highly linked in the development of these wind reversals. However, not all wind reversals appear to behave like propagating Kelvin waves and the analysis of coastal buoy observations for three years indicates that different types of disturbances occur. Both propagating disturbances and nonpropagating disturbances occur with similar frequencies. While the synoptic-scale characteristics associated with propagating and nonpropagating wind reversals are sometimes rather subtle, several distinct differences occur that suggest a direct link between the coastal dynamics and the synoptic-scale forcing. Synoptic forcing characterized by persistent low-level offshore flow favors the development of propagating disturbances, while weak, nonsustained offshore flow characterizes nonpropagating disturbances. These differences support the idea that propagating events represent a favorable interaction between the synoptic-scale forcing and the excitation and propagation of Kelvin waves, whereas nonpropagating events either represent a less favorable interaction or are simply trapped ageostrophic flow due to the synoptic scale without a Kelvin wave response. These dynamic differences imply different stratus behavior, which is important to forecasters.
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TUCCI, ROBERT R. "DIFFRACTION AND SQUEEZED LIGHT." International Journal of Modern Physics B 07, no. 26 (November 30, 1993): 4403–37. http://dx.doi.org/10.1142/s0217979293003735.
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We discuss the effect of diffraction on squeezed light propagation. All electric fields concerned are approximated to be monochromatic and paraxial. We consider: (1)(propagation without gain) a squeezed signal propagating in free space, and (2)(propagation with gain) a squeezed signal propagating in a non-linear crystal which amplifies the signal by a process of frequency halving (degenerate parametric amplification). The pump beam required for this process is assumed to have a Gaussian amplitude profile. For propagation without gain, our expression for the final signal is exact, but for propagation with gain, it is given as a perturbative expansion. The lowest order term in the expansion neglects diffraction of the signal and assumes flat pump wavefronts. Higher order terms include these factors and thus improve the accuracy with which the signal’s transverse behavior is described. We present graphs showing the dependence of squeezing on pump and signal beam parameters. We also find and discuss approximate formulas that characterize these graphs in various regimes.
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Yang, C. H., and M. F. Huang. "Measurement and Modelling for the Dispersion Relations of Acoustic Waves Propagating in a Free Piezoelectric Plate." Journal of Mechanics 19, no. 2 (June 2003): 311–18. http://dx.doi.org/10.1017/s1727719100004342.
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ABSTRACTThis research is focused in the measurement and modelling of the dispersion relations of Lamb waves propagating in a piezoelectric plate. A theoretical model based on a partial wave analysis is used to provide numerical calculations for the dispersion relations of Lamb waves propagating in an LiNbO3 plate with different propagating directions. The dispersion relations are presented in an innovative image format. A non-contact laser ultrasound technique operated in B-scan mode with the aid of double Fast Fourier transform signal-processing scheme is used to measured multi-mode dispersion realtions. Among all the propagation angles, the measured dispersion curves show good agreement with the theoretical calculations. The Rayleigh wave speeds are extracted from the measured and calculated dispersion curves, showing favorable comparison with classical theory by Campbell.
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GOMEZ, CHRISTOPHE. "LOSS OF RESOLUTION FOR THE TIME REVERSAL OF WAVES IN RANDOM UNDERWATER ACOUSTIC CHANNELS." Mathematical Models and Methods in Applied Sciences 23, no. 11 (July 23, 2013): 2065–110. http://dx.doi.org/10.1142/s0218202513500267.
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In this paper we analyze a time reversal experiment in a random underwater acoustic channel. In this kind of waveguide with a semi-infinite cross-section a propagating field can be decomposed over three kinds of modes: the propagating modes, the radiating modes and the evanescent modes. Using an asymptotic analysis based on a separation of scales technique we derive the asymptotic form of the the coupled mode power equation for the propagating modes. This approximation is used to compute the transverse profile of the refocused field and show that random inhomogeneities inside the waveguide deteriorate the spatial focusing. This result, in an underwater acoustic channel context, is a counterexample of the classical results about time reversal experiment in other configurations for which randomness in the propagation medium enhances the refocusing.
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Cai, Ming, Cory Barton, Chul-Su Shin, and Jeffrey M. Chagnon. "The Continuous Mutual Evolution of Equatorial Waves and the Quasi-Biennial Oscillation of Zonal Flow in the Equatorial Stratosphere*." Journal of the Atmospheric Sciences 71, no. 8 (July 23, 2014): 2878–85. http://dx.doi.org/10.1175/jas-d-14-0032.1.
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Abstract The continuous mutual evolution of equatorial waves and the background quasi-biennial oscillation (QBO) is demonstrated using daily NCEP–U.S. Department of Energy (DOE) reanalysis for the period from 1 January 1979 to 31 December 2010. Using a novel diagnostic technique, the phase speed, vertical tilting, and form stress of equatorial waves in the stratosphere are obtained continuously on a daily basis. The results indicate that, on top of a weak-amplitude annual-cycle signal, all of these wave properties have a pronounced QBO signal with a downward propagation that evolves continuously together with the background QBO. The analysis also highlights the potential role of wave-induced form stress in driving the QBO regime change. Dominant waves in the equatorial stratosphere propagate very slowly relative to the ground at all times, implying that their observed intrinsic phase speed evolution follows the background QBO nearly exactly but with opposite sign, as the established theory predicts. By revealing the continuous evolution of the form stress associated with the vertically tilted waves, the new diagnostic method also demonstrates the dominance of eastward-tilted, eastward-propagating waves contributing to a deceleration of easterly flow at high altitudes, which causes a downward propagation of the easterly flow signal. Similarly, the dominance of westward-tilted, westward-propagating waves acts to reverse westerly flow to easterly flow and causes a downward propagation of westerly flow signal. The results suggest that in addition to the wave-breaking processes, such continuously alternating downward transfer of westerly and easterly angular momentum by westward-tilted, westward-propagating waves and eastward-tilted, eastward-propagating waves contributes to the wave–mean flow interaction mechanism for the QBO.
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Song, Hong Wei, Zhen Luo, San San Ao, and Rui Wang. "Propagation Character of the Stress Wave in Weld Joints." Advanced Materials Research 199-200 (February 2011): 801–4. http://dx.doi.org/10.4028/www.scientific.net/amr.199-200.801.
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Stress wave test technique has broad prospects because of the long distance, large scale and relatively low cost. This paper studies the stress wave propagation characteristics in the butt weld joints in the case of external symmetrical impact. The stress wave propagating before and after the joints is measured by dynamic strain gauge. Then model analysis and simulation is applied to research stress wave. The results show the loss of stress wave is small. After spectrum analysis, the change of propagating stress wave can be detected.
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LEE, H. W., Y. S. MYUNG, JIN YOUNG KIM, and D. K. PARK. "UNSTABLE PROPAGATION OF BLACK STRINGS." Modern Physics Letters A 13, no. 09 (March 21, 1998): 701–13. http://dx.doi.org/10.1142/s0217732398000760.
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We investigate the five- and six-dimensional black strings within Einstein–Maxwell theory. The extremal black string solutions are endowed with the null Killing symmetry. Using this symmetry, we show that one graviton is a propagating mode, while both the Maxwell (ℱ) and three-form (ℋ) fields are non-propagating modes. Further we discuss the stability and classical hair of the extremal black strings. It turns out that for any mode with l≥0, this propagation is unstable and there is no time-dependent classical hair.
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Pritchard, Michael S., Mitchell W. Moncrieff, and Richard C. J. Somerville. "Orogenic Propagating Precipitation Systems over the United States in a Global Climate Model with Embedded Explicit Convection." Journal of the Atmospheric Sciences 68, no. 8 (August 1, 2011): 1821–40. http://dx.doi.org/10.1175/2011jas3699.1.
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Abstract In the lee of major mountain chains worldwide, diurnal physics of organized propagating convection project onto seasonal and climate time scales of the hydrologic cycle, but this phenomenon is not represented in conventional global climate models (GCMs). Analysis of an experimental version of the superparameterized (SP) Community Atmosphere Model (CAM) demonstrates that propagating orogenic nocturnal convection in the central U.S. warm season is, however, representable in GCMs that use the embedded explicit convection model approach [i.e., multiscale modeling frameworks (MMFs)]. SP-CAM admits propagating organized convective systems in the lee of the Rockies during synoptic conditions similar to those that generate mesoscale convective systems in nature. The simulated convective systems exhibit spatial scales, phase speeds, and propagation speeds comparable to radar observations, and the genesis mechanism in the model agrees qualitatively with established conceptual models. Convective heating and condensate structures are examined on both resolved scales in SP-CAM, and coherently propagating cloud “metastructures” are shown to transcend individual cloud-resolving model arrays. In reconciling how this new mode of diurnal convective variability is admitted in SP-CAM despite the severe idealizations in the cloud-resolving model configuration, an updated discussion is presented of what physics may transcend the re-engineered scale interface in MMFs. The authors suggest that the improved diurnal propagation physics in SP-CAM are mediated by large-scale first-baroclinic gravity wave interactions with a prognostic organization life cycle, emphasizing the physical importance of preserving “memory” at the inner resolved scale.
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Drbohlav, Hae-Kyung Lee, and Bin Wang. "Horizontal and Vertical Structures of the Northward-Propagating Intraseasonal Oscillation in the South Asian Monsoon Region Simulated by an Intermediate Model*." Journal of Climate 20, no. 16 (August 15, 2007): 4278–86. http://dx.doi.org/10.1175/jcli4244.1.
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Abstract The structures and mechanism of the northward-propagating boreal summer intraseasonal oscillation (BSISO) in the southern Asian monsoon region are simulated and investigated in a three-dimensional intermediate model (3D model). The horizontal structure of the intraseasonal variability in the 3D model depicts the Kelvin–Rossby wave–type disturbance, which may or may not produce the northward-propagating disturbance in the Indian Ocean, depending on the seasonal-mean background winds. Two experiments are conducted in order to identify what characteristic of seasonal-mean background can induce the northwestward-tilted band in the Kelvin–Rossby wave, whose overall eastward movement gives the impression of the northward propagation at a given longitude. When the prescribed boreal summer mean winds are excluded in the first experiment, the phase difference between the barotropic divergence tendency and convection disappears. Consequently, the Rossby wave–type convection forms a zonally elongated band. As a result, the northward propagation of convection at a given longitude disappears. When the easterly vertical shear is introduced in the second experiment, the horizontal and the vertical structures of BSISO become similar to that of the northward-propagating one. The reoccurrence of the northwestward-directed convective band and the phase difference between the barotropic divergence tendency and the convection suggest that the summer mean zonal winds in the boreal Indian summer monsoon region are a critical condition that causes the horizontal and vertical structures of northward-propagating BSISO in the southern Asian monsoon region.
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Kolobov, D. Y., and N. I. Kobanov. "Two modes of propagating waves in sunspots." Proceedings of the International Astronomical Union 3, S247 (September 2007): 105–9. http://dx.doi.org/10.1017/s1743921308014749.
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AbstractThe observations of sunspot chromosphere are presented. The authors suggest the existence of two modes of propagating waves at the chromospheric level. The connection between these modes and magnetic field topology can be inferred from the analysis of mode propagation velocity and spatial localization. Two hypotheses are tested to explain the phenomenon: “Visual pattern” and “Trans-sunspot wave”.
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Mills, Frederick V. "The Society in Scotland for Propagating Christian Knowledge In British North America, 1730–1775." Church History 63, no. 1 (March 1994): 15–30. http://dx.doi.org/10.2307/3167830.
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Three major Protestant missionary organizations—the Company for the ropagation of the Gospel in New England (the NEC, founded 1649), the Society for the Propagation of the Gospel in Foreign Parts (SPG, founded 1701), and the Society in Scotland for Propagating Christian Knowledge (SSPCK, founded 1709)—all played significant roles in Christianizing and civilizing the inhabitants of British North America. The New England Company had the longest history and is the oldest Protestant missionary organization. The Society for the Propagation of the Gospel in Foreign Parts sent no fewer than three hundred missionaries to America between 1701 and 1783. While the NEC and the SPG have received scholarly attention, the Society in Scotland for Propagating Christian Knowledge has been virtually ignored.
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Ma, Chien-Ching, and Yi-Shyong Ing. "Transient Analysis of Dynamic Crack Propagation With Boundary Effect." Journal of Applied Mechanics 62, no. 4 (December 1, 1995): 1029–38. http://dx.doi.org/10.1115/1.2896039.
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In this study, a dynamic antiplane crack propagation with constant velocity in a configuration with boundary is investigated in detail. The reflected cylindrical waves which are generated from the free boundary will interact with the propagating crack and make the problem extremely difficult to analyze. A useful fundamental solution is proposed in this study and the solution is determined by superposition of the fundamental solution in the Laplace transform domain. The proposed fundamental problem is the problem of applying exponentially distributed traction (in the Laplace transform domain) on the propagating crack faces. The Cagniard’s method for Laplace inversion is used to obtain the transient solution in time domain. Numerical results of dynamic stress intensity factors for the propagation crack are evaluated in detail.
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Ren, R.-C., and Ming Cai. "Meridional and Downward Propagation of Atmospheric Circulation Anomalies. Part II: Southern Hemisphere Cold Season Variability." Journal of the Atmospheric Sciences 65, no. 7 (July 1, 2008): 2343–59. http://dx.doi.org/10.1175/2007jas2594.1.
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Abstract As in the Northern Hemisphere, there exists a simultaneous poleward propagation of temperature anomalies in the stratosphere and equatorward propagation in the troposphere in the Southern Hemisphere’s cold season. It takes about 110 days for anomalies of one polarity to propagate from the equator to the pole (or half the period of the complete cycle), nearly twice as long as in the Northern Hemisphere. The earlier poleward propagation of temperature anomalies in upper levels compared with those in lower levels results in an apparent downward propagation in the stratosphere. Accompanying the poleward- and downward-propagating warm (cold) anomalies is a successive leveling (steepening) of isentropic surfaces, reflecting a simultaneous reduction (strengthening) of the meridional temperature gradient and increase (decrease) of the vertical static stability. Following changes in the thermal fields are poleward- and downward-propagating zonal wind anomalies of the opposite sign. The arrival of the poleward-propagating stratospheric thermal anomalies over the polar region coincides with the beginning of the compensating equatorward advancement of tropospheric thermal anomalies of the opposite sign. The synchronized meridional propagation in the thermal fields results from the temporal variation between stronger and weaker meridional mass circulations, which is responsible for a meridional out-of-phase variability pattern in both the stratosphere and troposphere and a vertical out-of-phase pattern between stratospheric and tropospheric temperature anomalies at high latitudes. The vertical alignment of a warm high (cold low) anomaly in the stratosphere overlying a cold high (warm low) anomaly at the surface explains the apparent “equivalent barotropic” structure in the height anomalies.
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Schneider, Edwin K. "Trajectory Analysis of the Mechanism for Westward Propagation of Rossby Waves." Journal of the Atmospheric Sciences 72, no. 5 (May 1, 2015): 2178–82. http://dx.doi.org/10.1175/jas-d-14-0242.1.
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Abstract An analysis of Rossby wave dynamics in two and three dimensions is carried from the point of view of a reference frame propagating with the zonal phase speed of the wave. Since trajectories and streamlines coincide in this reference frame, the mechanism for (westward) propagation of free waves has a different interpretation than in a reference frame fixed to the ground. In the wave reference frame, propagating free-wave solutions are possible only when parcels approach from the west. When parcels approach from the east, potential vorticity cannot be conserved along trajectories.
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Douglas, M., and I. Ballai. "MHD waves at a spherical interface modelling coronal global EIT waves." Proceedings of the International Astronomical Union 3, S247 (September 2007): 251–54. http://dx.doi.org/10.1017/s1743921308014944.
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AbstractEnergetically eruptive events such as flares and coronal mass ejections (CMEs) are known to generate global waves, propagating over large distances, sometimes comparable to the solar radius. In this contribution EIT waves are modelled as waves propagating at a spherical density interface in the presence of a radially expanding magnetic field. The generation and propagation of EIT waves is studied numerically for coronal parameters. Simple equilibria allow the explanation of the coronal dimming caused by EIT waves as a region of rarified plasma created by a siphon flow.