DYNAMICAL STUDY OF PHONONS IN FERROELECTRIC LEAD TITANATE

1981 ◽  
Vol 42 (C6) ◽  
pp. C6-433-C6-435
Author(s):  
R. S. Katiyar ◽  
J. D. Freire
Keyword(s):  
Lead Titanate ◽  
Dynamical Study

scholarly journals A Dynamical Study of Fusion Hindrance with Nakajima-Zwanzig Projection Method

2021 ◽  
Author(s):  
Yasuhisa Abe ◽  
David Boilley ◽  
Quentin Hourdillé ◽  
Caiwan Shen
Keyword(s):  
Cross Sections ◽  
Degrees Of Freedom ◽  
Operator Method ◽  
Initial Distribution ◽  
Physical Parameters ◽  
Relaxation Processes ◽  
Fast Variable ◽  
Dynamical Study ◽  
Injection Point ◽  
Slow Variables

Abstract A new framework is proposed for the study of collisions between very heavy ions which lead to the synthesis of Super-Heavy Elements (SHE), to address the fusion hindrance phenomenon. The dynamics of the reaction is studied in terms of collective degrees of freedom undergoing relaxation processes with different time scales. The Nakajima-Zwanzig projection operator method is employed to eliminate fast variable and derive a dynamical equation for the reduced system with only slow variables. There, the time evolution operator is renormalised and an inhomogeneous term appears, which represents a propagation of the given initial distribution. The term results in a slip to the initial values of the slow variables. We expect that gives a dynamical origin of the so-called “injection point s” introduced by Swiatecki et al in order to reproduce absolute values of measured cross sections for SHE. A formula for the slip is given in terms of physical parameters of the system, which confirms the results recently obtained with a Langevin equation, and permits us to compare various incident channels.

scholarly journals Dynamical study of infochemical influences on tropic interaction of diffusive plankton system

2021 ◽  
Vol 3 (3) ◽  
Author(s):  
Satish Kumar Tiwari ◽  
Ravikant Singh ◽  
Nilesh Kumar Thakur
Keyword(s):  
Dimethyl Sulfide ◽  
Algal Bloom ◽  
Turing Instability ◽  
Model System ◽  
Ode Model ◽  
Estuarine Ecosystem ◽  
Dynamical Study ◽  
Oscillatory Dynamics ◽  
The Stability ◽  
Microzooplankton Grazing

AbstractWe propose a model for tropic interaction among the infochemical-producing phytoplankton and non-info chemical-producing phytoplankton and microzooplankton. Volatile information-conveying chemicals (infochemicals) released by phytoplankton play an important role in the food webs of marine ecosystems. Microzooplankton is an ecologically important grazer of phytoplankton for coexistence of a large number of phytoplankton species. Here, we discuss how information transferred by dimethyl sulfide shapes the interaction of phytoplankton. Phytoplankton deterrents may lead to propagation of IPP bloom. The interaction between IPP and microzooplankton follows the Beddington–DeAngelis-type functional response. Analytically, we discuss boundedness, stability and Turing instability of the model system. We perform numerical simulation for temporal (ODE model) as well as a spatial model system. Our numerical investigation shows that microzooplankton grazing refuse of IPP leads to oscillatory dynamics. Increasing diffusion coefficient of microzooplankton shows Turing instability. Time evolution also plays an important role in the stability of system dynamics. The results obtained in this paper are useful to understand the dominance of algal bloom in coastal and estuarine ecosystem.

scholarly journals A thermophysical and dynamical study of the Hildas (1162) Larissa and (1911) Schubart

2021 ◽  
Author(s):  
Cristian F Chavez ◽  
T G Müller ◽  
J P Marshall ◽  
J Horner ◽  
H Drass ◽  
...  
Keyword(s):  
Thermal Inertia ◽  
Infrared Camera ◽  
Asteroid Belt ◽  
Effective Diameter ◽  
Early Solar System ◽  
Dynamical Study ◽  
Axis Ratio ◽  
Ellipsoidal Shape ◽  
Dynamical Simulations ◽  
Taxonomical Classification

Abstract The Hilda asteroids are among the least studied populations in the asteroid belt, despite their potential importance as markers of Jupiter’s migration in the early Solar system. We present new mid-infrared observations of two notable Hildas, (1162) Larissa and (1911) Schubart, obtained using the Faint Object infraRed CAmera for the SOFIA Telescope (FORCAST), and use these to characterise their thermal inertia and physical properties. For (1162) Larissa, we obtain an effective diameter of 46.5$^{+2.3}_{-1.7}$ km, an albedo of 0.12 ± 0.02, and a thermal inertia of 15$^{+10}_{-8}$ Jm−2s1/2K−1. In addition, our Larissa thermal measurements are well matched with an ellipsoidal shape with an axis ratio a/b=1.2 for the most-likely spin properties. Our modelling of (1911) Schubart is not as refined, but the thermal data point towards a high-obliquity spin-pole, with a best-fit a/b=1.3 ellipsoidal shape. This spin-shape solution is yielding a diameter of 72$^{+3}_{-4}$ km, an albedo of 0.039± 0.02, and a thermal inertia below 30 Jm−2s1/2K−1 (or 10$^{+20}_{-5}$ Jm−2s1/2K−1). As with (1162) Larissa, our results suggest that (1911) Schubart is aspherical, and likely elongated in shape. Detailed dynamical simulations of the two Hildas reveal that both exhibit strong dynamical stability, behaviour that suggests that they are primordial, rather than captured objects. The differences in their albedos, along with their divergent taxonomical classification, suggests that despite their common origin, the two have experienced markedly different histories.

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