Experimental Observations of Propagating Waves and Switching Phenomena in a Coupled Bistable Oscillator System

2014 ◽  
Vol 24 (12) ◽  
pp. 1450157 ◽  
Author(s):  
Kuniyasu Shimizu
Keyword(s):  
Invariant Subspace ◽  
Spectral Distribution ◽  
Numerical Results ◽  
Periodic Waves ◽  
Bifurcation Diagrams ◽  
Propagating Waves ◽  
Different Types ◽  
The Stability ◽  
The One ◽  
Parameter Bifurcation

In this study, we construct a circuit composed of bistable oscillators and we report the experimental observations of quasi-periodic waves propagating in the circuit and compare them with the associated numerical results. Two different types of propagating quasi-periodic waves with identical parameter sets are experimentally verified. The associated numerical results are distinguished by comparing trajectories on the phase planes and by analyzing the one-parameter bifurcation diagrams. Furthermore, the experiments reveal five different types of switching oscillations. The associated numerical results are also presented, and the stability of the switching oscillations (when constrained to an invariant subspace) is numerically investigated. We also calculate spectral distribution for one type of the switching oscillation.

Stability and Vibrations of Geometrically Nonlinear Cylindrically Orthotropic Circular Plates

1984 ◽  
Vol 51 (2) ◽  
pp. 354-360 ◽  
Author(s):  
D. Shilkrut
Keyword(s):  
Stability Analysis ◽  
Qualitative Methods ◽  
Dynamic Method ◽  
Numerical Results ◽  
Geometrically Nonlinear ◽  
Circular Plates ◽  
Different Types ◽  
The Stability ◽  
Thermal Influence ◽  
Cylindrically Orthotropic

The stability analysis of axisymmetrical equilibrium states of geometrically nonlinear, orthotropic, circular plates that are deformed by multiparameter loading, including thermal influence, is presented. The dynamic method (method of small vibrations) is used to accomplish this purpose. The behavior of the plate in different cases is revealed. In particular, it is shown that two different types of snapping processes can occur. The values of frequencies of small eigenvibrations from various cases have been calculated. These investigations are realized by numerical and qualitative methods. Here only the numerical results are presented.

The stability of viscous flow between rotating cylinders. II

1962 ◽  
Vol 268 (1333) ◽  
pp. 145-152 ◽  
Keyword(s):  
Viscous Flow ◽  
Present Method ◽  
Adjoint System ◽  
Numerical Results ◽  
New Method ◽  
System Of Equations ◽  
Rotating Cylinders ◽  
Characteristic Value ◽  
The Stability ◽  
The One

In this paper a new method is described for solving the characteristic value problem underlying the theory of the stability of viscous flow between rotating cylinders. The method depends on solving a simpler adjoint system of equations. It is shown that the present method is superior to the one described in an earlier paper (Chandrasekhar 1958). Numerical results are given for the case when the ratio of the radii of the two cylinders is one-half.

The Effects of Recombination in Expanding Gas Flows

1969 ◽  
Vol 22 (6) ◽  
pp. 739
Author(s):  
RL Pope
Keyword(s):  
Numerical Solutions ◽  
Numerical Results ◽  
Gas Flows ◽  
Approximate Analysis ◽  
One Dimensional ◽  
Different Types ◽  
Frozen State ◽  
The One

An approximate analysis of the one� dimensional expanding flow of an ideal dissociating gas, which is initially in a frozen state, is presented. The different types of solutions of the equations of the flow, for variations in the rates of expansion and recombination, are discussed. Some numerical results indicating the distances and other dimensions involved are included. The results of the approximate analysis are compared with some numerical solutions and are found to be valid for all cases in which the analysis can be expected to apply.

scholarly journals ЛІСІВНИЧО-ТАКСАЦІЙНІ ОСОБЛИВОСТІ ГРАБНЯКІВ ПРИРОДНОГО ЗАПОВІДНИКА «МЕДОБОРИ»

2020 ◽  
Vol 78 (4) ◽  
pp. 6-10
Author(s):  
U. O. Bachynska
Keyword(s):  
Age Groups ◽  
Anthropogenic Factors ◽  
Zonal Vegetation ◽  
Oak Trees ◽  
Different Types ◽  
Seed Origin ◽  
The Stability ◽  
The One ◽  
Natural And Anthropogenic Factors ◽  
L 13

In the Nature Reserve of Medobory a zonal vegetation is represented by dark deciduous forests, with a hornbeam and oak trees mainly, dominated by Quercus robur, Caprius betulus, and Flaxinus excelsior. Within the tree stands hornbeam predominates on the area of 21.7% of the forested lands of the reserve. Preliminary investigations of the Reserve hornbeam plantations were conducted by Mykola Korol and Ihor Humeniuk. They pointed to the stability of these plantations, their high competitive abilities but depleted biotic potential. The objects, selected for the study, are permanent trial areas, where during the last taxation measurements the hornbeam dominations in the tree stands were observed (with the tree stands of 6 and more items). On the studied trial areas mature and overmature plantations prevail by age groups. The hornbeams grow here mainly in young hornbeam forests in the first, second and third bonitets. The predominant number of trees on the trial areas is hornbeam of seed origin. Except L-28, where the conditions of growth are dry oakery on the rock, the hornbeams grow on the third bonitet and are of sprouting origin mainly. The tree stands on the trial areas are of the same age. As for the age groups they are mature and overmature, except for L-13 and L-28, where the young stocks grow, and L-13, where the one of a middle age grow. The tree stands taxation indicators on the trial areas are characterized by some differences, depending on age and completeness, within different types. The stock of live wood is on average 115-463 cubic metres per hectare. Trees differentiations by the degree of thickness show the process of a plant formation depending on their origin and age. On the trial areas the renewal of a hornbeam is represented by one- and two-years-old undergrowth. The forest stands are characterized by insignificant variability of their taxation structure indicators, being the result of a slight influence of natural and anthropogenic factors.

scholarly journals The Fractional Form of the Tinkerbell Map Is Chaotic

2018 ◽  
Vol 8 (12) ◽  
pp. 2640 ◽  
Author(s):  
Adel Ouannas ◽  
Amina-Aicha Khennaoui ◽  
Samir Bendoukha ◽  
Thoai Vo ◽  
Viet-Thanh Pham ◽  
...  
Keyword(s):  
Lyapunov Exponents ◽  
Stability Theory ◽  
Chaotic Map ◽  
Discrete Systems ◽  
Numerical Results ◽  
Asymptotic Convergence ◽  
Bifurcation Diagrams ◽  
Difference Form ◽  
The Stability

This paper is concerned with a fractional Caputo-difference form of the well-known Tinkerbell chaotic map. The dynamics of the proposed map are investigated numerically through phase plots, bifurcation diagrams, and Lyapunov exponents considered from different perspectives. In addition, a stabilization controller is proposed, and the asymptotic convergence of the states is established by means of the stability theory of linear fractional discrete systems. Numerical results are employed to confirm the analytical findings.

Use of a Lyophilized Reference Plasma to Compare Coagulation Test Procedures

1975 ◽  
Vol 34 (02) ◽  
pp. 426-444 ◽  
Author(s):  
J Kahan ◽  
I Nohén
Keyword(s):  
Oral Anticoagulant Therapy ◽  
Repeated Measurements ◽  
Test Procedures ◽  
Coagulation Activity ◽  
Close Relationship ◽  
Measured Activity ◽  
Test Materials ◽  
The Difference ◽  
The Stability ◽  
The One

SummaryIn 4 collaborative trials, involving a varying number of hospital laboratories in the Stockholm area, the coagulation activity of different test materials was estimated with the one-stage prothrombin tests routinely used in the laboratories, viz. Normotest, Simplastin-A and Thrombotest. The test materials included different batches of a lyophilized reference plasma, deep-frozen specimens of diluted and undiluted normal plasmas, and fresh and deep-frozen specimens from patients on long-term oral anticoagulant therapy.Although a close relationship was found between different methods, Simplastin-A gave consistently lower values than Normotest, the difference being proportional to the estimated activity. The discrepancy was of about the same magnitude on all the test materials, and was probably due to a divergence between the manufacturers’ procedures used to set “normal percentage activity”, as well as to a varying ratio of measured activity to plasma concentration. The extent of discrepancy may vary with the batch-to-batch variation of thromboplastin reagents.The close agreement between results obtained on different test materials suggests that the investigated reference plasma could be used to calibrate the examined thromboplastin reagents, and to compare the degree of hypocoagulability estimated by the examined PIVKA-insensitive thromboplastin reagents.The assigned coagulation activity of different batches of the reference plasma agreed closely with experimentally obtained values. The stability of supplied batches was satisfactory as judged from the reproducibility of repeated measurements. The variability of test procedures was approximately the same on different test materials.

Structure, Stability and Water Adsorption on Ultra-Thin TiO2 Supported on TiN

2019 ◽  
Author(s):  
Jose Julio Gutierrez Moreno ◽  
Marco Fronzi ◽  
Pierre Lovera ◽  
alan O'Riordan ◽  
Mike J Ford ◽  
...  
Keyword(s):  
Density Functional ◽  
Water Adsorption ◽  
Chemical Potential ◽  
Energy Gap ◽  
Molecular Water ◽  
Structure Stability ◽  
Ambient Conditions ◽  
Rutile Structure ◽  
The Stability ◽  
The One

<p></p><p>Interfacial metal-oxide systems with ultrathin oxide layers are of high interest for their use in catalysis. In this study, we present a density functional theory (DFT) investigation of the structure of ultrathin rutile layers (one and two TiO<sub>2</sub> layers) supported on TiN and the stability of water on these interfacial structures. The rutile layers are stabilized on the TiN surface through the formation of interfacial Ti–O bonds. Charge transfer from the TiN substrate leads to the formation of reduced Ti<sup>3+</sup> cations in TiO<sub>2.</sub> The structure of the one-layer oxide slab is strongly distorted at the interface, while the thicker TiO<sub>2</sub> layer preserves the rutile structure. The energy cost for the formation of a single O vacancy in the one-layer oxide slab is only 0.5 eV with respect to the ideal interface. For the two-layer oxide slab, the introduction of several vacancies in an already non-stoichiometric system becomes progressively more favourable, which indicates the stability of the highly non-stoichiometric interfaces. Isolated water molecules dissociate when adsorbed at the TiO<sub>2</sub> layers. At higher coverages the preference is for molecular water adsorption. Our ab initio thermodynamics calculations show the fully water covered stoichiometric models as the most stable structure at typical ambient conditions. Interfacial models with multiple vacancies are most stable at low (reducing) oxygen chemical potential values. A water monolayer adsorbs dissociatively on the highly distorted 2-layer TiO<sub>1.75</sub>-TiN interface, where the Ti<sup>3+</sup> states lying above the top of the valence band contribute to a significant reduction of the energy gap compared to the stoichiometric TiO<sub>2</sub>-TiN model. Our results provide a guide for the design of novel interfacial systems containing ultrathin TiO<sub>2</sub> with potential application as photocatalytic water splitting devices.</p><p></p>

ASSESSMENT OF PINE CROPS GROWTH IN BAIMAK FORESTRY

2020 ◽  
Vol 37 (3) ◽  
pp. 83-90
Author(s):  
T.Z. Mutallapov ◽  
Keyword(s):  
Scots Pine ◽  
Forest Ecosystem ◽  
Distribution Curve ◽  
Comparative Assessment ◽  
Tree Distribution ◽  
Entire Structure ◽  
Structure Changes ◽  
Large Trees ◽  
Different Types ◽  
The Stability

The article presents the results of evaluating the growth of Scots pine in the Baymak forest area. The analysis of forestry and taxation indicators of Scots pine crops on the studied sample areas is carried out, and a comparative assessment of the growth of forest crops growing in different types of forest is given. Increased competition in plantings leads to the natural decline of stunted trees, which is the result of differentiation in the stand. As a result, its structure changes, the number of large trees increases, and, accordingly, the stability of the forest ecosystem increases. In this regard, the appearance of the tree distribution curve by thickness levels also changes. It becomes more "flat", and its competitive load is more evenly distributed over the entire structure of the stand, and competition is weakened.

A Survey on Computational Methods for Essential Proteins and Genes Prediction

2019 ◽  
Vol 14 (3) ◽  
pp. 211-225 ◽  
Author(s):  
Ming Fang ◽  
Xiujuan Lei ◽  
Ling Guo
Keyword(s):  
Computational Methods ◽  
Drug Targets ◽  
Disease Genes ◽  
Essential Proteins ◽  
Experimental Identification ◽  
Cellular Life ◽  
Different Types ◽  
The Stability ◽  
Human Disease Genes ◽  
Biology Research

Background: Essential proteins play important roles in the survival or reproduction of an organism and support the stability of the system. Essential proteins are the minimum set of proteins absolutely required to maintain a living cell. The identification of essential proteins is a very important topic not only for a better comprehension of the minimal requirements for cellular life, but also for a more efficient discovery of the human disease genes and drug targets. Traditionally, as the experimental identification of essential proteins is complex, it usually requires great time and expense. With the cumulation of high-throughput experimental data, many computational methods that make useful complements to experimental methods have been proposed to identify essential proteins. In addition, the ability to rapidly and precisely identify essential proteins is of great significance for discovering disease genes and drug design, and has great potential for applications in basic and synthetic biology research. Objective: The aim of this paper is to provide a review on the identification of essential proteins and genes focusing on the current developments of different types of computational methods, point out some progress and limitations of existing methods, and the challenges and directions for further research are discussed.

scholarly journals Computational Analysis of Ca2+ Oscillatory Bio-Signals: Two-Parameter Bifurcation Diagrams

Entropy ◽  
2021 ◽  
Vol 23 (7) ◽  
pp. 876
Author(s):  
Wieslaw Marszalek ◽  
Jan Sadecki ◽  
Maciej Walczak
Keyword(s):  
Equilibrium Points ◽  
Autonomous Systems ◽  
Cytosolic Calcium ◽  
Calcium Oscillations ◽  
Dynamical Model ◽  
Bifurcation Diagrams ◽  
Step Size ◽  
Oscillatory Systems ◽  
Two Parameter ◽  
Parameter Bifurcation

Two types of bifurcation diagrams of cytosolic calcium nonlinear oscillatory systems are presented in rectangular areas determined by two slowly varying parameters. Verification of the periodic dynamics in the two-parameter areas requires solving the underlying model a few hundred thousand or a few million times, depending on the assumed resolution of the desired diagrams (color bifurcation figures). One type of diagram shows period-n oscillations, that is, periodic oscillations having n maximum values in one period. The second type of diagram shows frequency distributions in the rectangular areas. Each of those types of diagrams gives different information regarding the analyzed autonomous systems and they complement each other. In some parts of the considered rectangular areas, the analyzed systems may exhibit non-periodic steady-state solutions, i.e., constant (equilibrium points), oscillatory chaotic or unstable solutions. The identification process distinguishes the later types from the former one (periodic). Our bifurcation diagrams complement other possible two-parameter diagrams one may create for the same autonomous systems, for example, the diagrams of Lyapunov exponents, Ls diagrams for mixed-mode oscillations or the 0–1 test for chaos and sample entropy diagrams. Computing our two-parameter bifurcation diagrams in practice and determining the areas of periodicity is based on using an appropriate numerical solver of the underlying mathematical model (system of differential equations) with an adaptive (or constant) step-size of integration, using parallel computations. The case presented in this paper is illustrated by the diagrams for an autonomous dynamical model for cytosolic calcium oscillations, an interesting nonlinear model with three dynamical variables, sixteen parameters and various nonlinear terms of polynomial and rational types. The identified frequency of oscillations may increase or decrease a few hundred times within the assumed range of parameters, which is a rather unusual property. Such a dynamical model of cytosolic calcium oscillations, with mitochondria included, is an important model in which control of the basic functions of cells is achieved through the Ca2+ signal regulation.

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