Hysteresis in entropy production in a model chemical reaction exhibiting subcritical Hopf bifurcation

1999 ◽  
Vol 110 (2) ◽  
pp. 1061-1063 ◽  
Author(s):  
A. K. Dutt
Keyword(s):  
Hopf Bifurcation ◽  
Entropy Production ◽  
Chemical Reaction ◽  
Subcritical Hopf Bifurcation ◽  
Model Chemical Reaction

Erratum: Calculation of the rate of entropy production for a model chemical reaction [J. Chem. Phys. 89, 1064 (1988)]

1988 ◽  
Vol 89 (11) ◽  
pp. 7039-7039
Author(s):  
Benjamin R. Irvin ◽  
John Ross
Keyword(s):  
Entropy Production ◽  
Chemical Reaction ◽  
Chem Phys ◽  
Model Chemical Reaction

Calculation of the rate of entropy production for a model chemical reaction

1988 ◽  
Vol 89 (2) ◽  
pp. 1064-1066 ◽  
Author(s):  
Benjamin R. Irvin ◽  
John Ross
Keyword(s):  
Entropy Production ◽  
Chemical Reaction ◽  
Model Chemical Reaction

Complete monotonicity of entropy production in chemical reaction

1981 ◽  
Vol 46 (2) ◽  
pp. 452-456
Author(s):  
Milan Šolc
Keyword(s):  
Entropy Production ◽  
Equilibrium Constant ◽  
Chemical Reaction ◽  
Relative Entropy ◽  
Order Reaction ◽  
Complete Monotonicity ◽  
First Order Reaction ◽  
First Order ◽  
Completely Monotonic ◽  
Derivatives Of

The successive time derivatives of relative entropy and entropy production for a system with a reversible first-order reaction alternate in sign. It is proved that the relative entropy for reactions with an equilibrium constant smaller than or equal to one is completely monotonic in the whole definition interval, and for reactions with an equilibrium constant larger than one this function is completely monotonic at the beginning of the reaction and near to equilibrium.

Subcritical Hopf bifurcation in NeNd hollow cathode discharge

1994 ◽  
Vol 196 (3-4) ◽  
pp. 191-194 ◽  
Author(s):  
P.R. Sasi Kumar ◽  
V.P.N. Nampoori ◽  
C.P.G. Vallabhan
Keyword(s):  
Hopf Bifurcation ◽  
Hollow Cathode ◽  
Hollow Cathode Discharge ◽  
Subcritical Hopf Bifurcation

Nonlinear Vibration Analysis of a Flexible Rotor Supported by a Flexure Pivot Tilting Pad Journal Bearing in Comparison to a Fixed Profile Journal Bearing with Experimental Verification

2021 ◽  
Author(s):  
Nuntaphong Koondilogpiboon ◽  
Tsuyoshi Inoue
Keyword(s):  
Hopf Bifurcation ◽  
Journal Bearing ◽  
Flexible Rotor ◽  
Maximum Test ◽  
Operating Region ◽  
Stable Operating ◽  
Subcritical Hopf Bifurcation ◽  
Tilting Pad ◽  
Calculation Results ◽  
Tilting Pad Journal Bearing

Abstract In this paper, an efficient numerical method consisting of the real mode component mode synthesis (CMS) model reduction, shooting method with parallel computing, and Floquet analysis was developed for nonlinear rotordynamics analysis of a flexible rotor supported by a 4-lobe flexure pivot tilting pad journal bearing (FPTPJB) in load-on-pad (LOP) and load-between-pad (LBP) orientations in comparison to a fixed profile journal bearing (JB) of the same pad geometry. The method used the rotor's finite elements and bearing forces obtained from directly solving the Reynolds equation to determine the limit cycles and Hopf bifurcation types. For the investigated rotor and bearing parameters, the numerical results indicated that the onset speed of instability (OSI) of FPTPJB is considerably higher than that of JB of the same orientation. Also, FPTPJB in LOP orientation yielded higher OSI than the LBP one, whereas the OSI of JB in LOP orientation was substantially higher than the LBP counterpart. Nonlinear calculation results indicated that all bearing types and orientations gave subcritical Hopf bifurcation. The FPTPJB in LOP orientation produced the largest stable operating region, whereas the JB in LBP configuration yield the smallest one. The experiment showed subcritical Hopf bifurcation occurred at speed close to the calculated OSI in all cases except FPTPJB in LOP orientation that the OSI is higher than the maximum test rig speed. The whirling orbit had the same frequency as the first critical speed and precessed in the direction of shaft rotation.

scholarly journals Modelling HIV dynamics with cell-to-cell transmission and CTL response

2021 ◽  
Author(s):  
Zirui Zhu ◽  
Ranchao Wu ◽  
Yu Yang ◽  
Yancong Xu
Keyword(s):  
Hopf Bifurcation ◽  
Cell Interaction ◽  
Backward Bifurcation ◽  
Hiv Treatment ◽  
Hiv Model ◽  
Ctl Response ◽  
Hiv Dynamics ◽  
Subcritical Hopf Bifurcation ◽  
Cell Transmission ◽  
New Type

In most HIV models, the emergence of backward bifurcation means that the control for basic reproduction number less than one is no longer effective for HIV treatment. In this paper, we study an HIV model with CTL response and cell-to-cell transmission by using the dynamical approach. The local and global stability of equilibria is investigated, the relations of subcritical Hopf bifurcation and supercritical bifurcation points are revealed, especially, the so-called new type bifurcation is also found with two Hopf bifurcation curves meeting at the same Bogdanov-Takens bifurcation point. Forward and backward bifurcation, Hopf bifurcation, saddle-node bifurcation, Bogdanov-Takens bifurcation are investigated analytically and numerically. Two limit cycles are also found numerically, which indicates that the complex behavior of HIV dynamics. Interestingly, the role of cell-to-cell interaction is fully uncovered, it may cause the oscillations to disappear and keep the so-called new type bifurcation persist. Finally, some conclusions and discussions are also given.

SUBCRITICAL HOPF BIFURCATION AT PHONATION ONSET

1998 ◽  
Vol 218 (2) ◽  
pp. 344-349 ◽  
Author(s):  
J.C. Lucero
Keyword(s):  
Hopf Bifurcation ◽  
Subcritical Hopf Bifurcation

scholarly journals Analysis of Entropy Production in Structured Chemical Reactors: Optimization for Catalytic Combustion of Air Pollutants

Entropy ◽  
2020 ◽  
Vol 22 (9) ◽  
pp. 1017 ◽  
Author(s):  
Mateusz Korpyś ◽  
Anna Gancarczyk ◽  
Marzena Iwaniszyn ◽  
Katarzyna Sindera ◽  
Przemysław J. Jodłowski ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Entropy Production ◽  
Heat And Mass Transfer ◽  
Chemical Reaction ◽  
Catalytic Combustion ◽  
Packed Bed ◽  
Optimization Criterion ◽  
Rational Solutions ◽  
Short Channel ◽  
Flow Friction

Optimization of structured reactors is not without some difficulties due to highly random economic issues. In this study, an entropic approach to optimization is proposed. The model of entropy production in a structured catalytic reactor is introduced and discussed. Entropy production due to flow friction, heat and mass transfer and chemical reaction is derived and referred to the process yield. The entropic optimization criterion is applied for the case of catalytic combustion of methane. Several variants of catalytic supports are considered including wire gauzes, classic (long-channel) and short-channel monoliths, packed bed and solid foam. The proposed entropic criterion may indicate technically rational solutions of a reactor process that is as close as possible to the equilibrium, taking into account all the process phenomena such as heat and mass transfer, flow friction and chemical reaction.

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