On a 1D Viscous Reactive and Radiative Gas with First-order Arrhenius Kinetics

2012 ◽  
pp. 127-163
Author(s):  
Yuming Qin ◽  
Lan Huang
Keyword(s):  
Arrhenius Kinetics ◽  
First Order

Asymptotic analysis of premixed burning with large activation energy

1972 ◽  
Vol 56 (1) ◽  
pp. 81-95 ◽  
Author(s):  
Francis E. Fendell
Keyword(s):  
Laminar Flame ◽  
Lewis Number ◽  
Spherically Symmetric ◽  
Arrhenius Kinetics ◽  
Finite Rate ◽  
Activation Temperature ◽  
One Dimensional ◽  
First Order ◽  
Monomolecular Decomposition ◽  
Kinetics Of

The structure and propagation rates of premixed flames are determined by singular perturbation in the limit where the activation temperature is large relative to other flow temperatures for several basic flows. Specifically, the simple kinetics of an exothermic first-order monomolecular decomposition under Arrhenius kinetics is studied for one-dimensional laminar flame propagation, spherically symmetric quasi-steady monopropellant droplet burning, and other simple geometries. Results elucidate Lewis-number effects, losses owing to fuel gasification processes, and conditions under which the thin-flame approximation is a limit of finite-rate Arrhenius kinetics.

scholarly journals Dynamics and control of loop reactors - a review

2021 ◽  
Author(s):  
Moshe Sheintuch ◽  
Olga Nekhamkina
Keyword(s):  
Infinite Number ◽  
Front Propagation ◽  
Complex Frequency ◽  
Periodic Operation ◽  
Arrhenius Kinetics ◽  
First Order ◽  
Dynamics And Control ◽  
Moving Coordinate ◽  
And Control ◽  
Propagation Velocities

In loop reactors the system is composed of several reactor units that are  organized in a loop and the feeding takes place at one of several ports with switching of the feed port. In its simplest operation a pulse is formed and rotates around it, producing high temperatures which enable combustion of dilute streams.  A limiting model with infinite number of units was derived. Rotating pulses, steady in a moving coordinate, emerge in both models when the switching to front propagation velocities ~1. But this behavior exists over a narrow domain. Simulations were conducted with generic first order Arrhenius kinetics. Experimental observations are reviewed. Outside the narrow frozen rotating pattern domain the system may exhibit multi- or quasi-periodic operation separated by domains of inactive reaction. The bifurcation set incorporates many 'finger'-like domains of complex frequency-locked solutions that allow to extend the operation domain with higher feed temperatures. Control is necessary to attain stable simple rotating frozen pattern within the narrow domains of active operation. Various tested control approaches are reviewed.          Actual implementation of combustion in LR will involve several reactants of different ignition temperatures. Design and control should be aimed at producing locked fronts and avoid extinction of slower reactions.

scholarly journals The Profound Unravelling of Equilibrium Thermodynamics and Arrhenius First-Order Kinetics in Relation to Metal Hydride Desorption Reactions

2021 ◽  
Author(s):  
Roland Hermann Pawelke
Keyword(s):  
Metal Hydride ◽  
Thermodynamic Factor ◽  
Equilibrium Thermodynamics ◽  
Arrhenius Kinetics ◽  
Closed Solution ◽  
Transient Behaviour ◽  
First Order ◽  
First Order Kinetics ◽  
Rate Limiting ◽  
Profound Insight

<div> <p>Approaching the entanglement problem of kinetics with thermodynamics in reversible metal hydride desorption reactions by means of a hyperbola template such as the Michaelis-Menten curve renders a closed solution for their unravelling possible, revealing profound insight of general significance into both, the structure of the rate-limiting thermodynamic factor and the nature of experiment-specific first-order Arrhenius kinetics. As by-product an alternate method of extreme simplicity for modelling transient behaviour of reversible metal hydride tanks is obtained. This paper concludes a series of works concerned with objectively approaching metal hydride soprtion reaction kinetics.</p></div>

The Profound Unravelling of Equilibrium Thermodynamics and Arrhenius First-Order Kinetics in Relation to Metal Hydride Desorption Reactions

2021 ◽  
Author(s):  
Roland Hermann Pawelke
Keyword(s):  
Metal Hydride ◽  
Thermodynamic Factor ◽  
Equilibrium Thermodynamics ◽  
Arrhenius Kinetics ◽  
Closed Solution ◽  
Transient Behaviour ◽  
First Order ◽  
First Order Kinetics ◽  
Rate Limiting ◽  
Profound Insight

<div> <p>Approaching the entanglement problem of kinetics with thermodynamics in reversible metal hydride desorption reactions by means of a hyperbola template such as the Michaelis-Menten curve renders a closed solution for their unravelling possible, revealing profound insight of general significance into both, the structure of the rate-limiting thermodynamic factor and the nature of experiment-specific first-order Arrhenius kinetics. As by-product an alternate method of extreme simplicity for modelling transient behaviour of reversible metal hydride tanks is obtained. This paper concludes a series of works concerned with objectively approaching metal hydride soprtion reaction kinetics.</p></div>

Dual systems for all: Higher-order, role-based relational reasoning as a uniquely derived feature of human cognition

2019 ◽  
Vol 42 ◽  
Author(s):  
Daniel J. Povinelli ◽  
Gabrielle C. Glorioso ◽  
Shannon L. Kuznar ◽  
Mateja Pavlic
Keyword(s):  
Temporal Reasoning ◽  
Higher Order ◽  
Important Case ◽  
Human Cognition ◽  
Relational Reasoning ◽  
Dual Systems ◽  
First Order ◽  
Reasoning System ◽  
Role Based

Abstract Hoerl and McCormack demonstrate that although animals possess a sophisticated temporal updating system, there is no evidence that they also possess a temporal reasoning system. This important case study is directly related to the broader claim that although animals are manifestly capable of first-order (perceptually-based) relational reasoning, they lack the capacity for higher-order, role-based relational reasoning. We argue this distinction applies to all domains of cognition.

Stochasting modeling of planetary ring systems

1984 ◽  
Vol 75 ◽  
pp. 461-469 ◽  
Author(s):  
Robert W. Hart
Keyword(s):  
Maximum Entropy ◽  
Ring System ◽  
The Sun ◽  
Ultimate State ◽  
Interparticle Interactions ◽  
Ring Systems ◽  
First Order ◽  
Planetary Ring ◽  
Insight Into

ABSTRACTThis paper models maximum entropy configurations of idealized gravitational ring systems. Such configurations are of interest because systems generally evolve toward an ultimate state of maximum randomness. For simplicity, attention is confined to ultimate states for which interparticle interactions are no longer of first order importance. The planets, in their orbits about the sun, are one example of such a ring system. The extent to which the present approximation yields insight into ring systems such as Saturn's is explored briefly.

Morphological studies of linear (AB)n multiblock copolymers and their blends

1992 ◽  
Vol 50 (1) ◽  
pp. 384-385
Author(s):  
Richard J. Spontak ◽  
Steven D. Smith ◽  
Arman Ashraf
Keyword(s):  
Electron Microscopy ◽  
Microphase Separation ◽  
Multiblock Copolymers ◽  
First Order ◽  
Morphological Studies ◽  
Transmission Electron ◽  
First Order Phase Transition ◽  
Covalently Bonded ◽  
Total Molecular Weight ◽  
First Order Phase

Block copolymers are composed of sequences of dissimilar chemical moieties covalently bonded together. If the block lengths of each component are sufficiently long and the blocks are thermodynamically incompatible, these materials are capable of undergoing microphase separation, a weak first-order phase transition which results in the formation of an ordered microstructural network. Most efforts designed to elucidate the phase and configurational behavior in these copolymers have focused on the simple AB and ABA designs. Few studies have thus far targeted the perfectly-alternating multiblock (AB)n architecture. In this work, two series of neat (AB)n copolymers have been synthesized from styrene and isoprene monomers at a composition of 50 wt% polystyrene (PS). In Set I, the total molecular weight is held constant while the number of AB block pairs (n) is increased from one to four (which results in shorter blocks). Set II consists of materials in which the block lengths are held constant and n is varied again from one to four (which results in longer chains). Transmission electron microscopy (TEM) has been employed here to investigate the morphologies and phase behavior of these materials and their blends.

Exact First Order Finite Element Modeling for Eddy Current NDE

1991 ◽  
Vol 3 (1) ◽  
pp. 235-253 ◽  
Author(s):  
L. D. Philipp ◽  
Q. H. Nguyen ◽  
D. D. Derkacht ◽  
D. J. Lynch ◽  
A. Mahmood
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Eddy Current ◽  
Element Modeling ◽  
First Order ◽  
Eddy Current Nde

Challenging the Multidimensional Conception of Perceived Person-Environment Fit

2020 ◽  
pp. 1-9
Author(s):  
Julian M. Etzel ◽  
Gabriel Nagy
Keyword(s):  
Higher Education ◽  
University Students ◽  
Educational Outcomes ◽  
Factor Model ◽  
Higher Order ◽  
Substantial Proportion ◽  
Unique Variance ◽  
First Order ◽  
Person Environment Fit ◽  
Order Factor

Abstract. In the current study, we examined the viability of a multidimensional conception of perceived person-environment (P-E) fit in higher education. We introduce an optimized 12-item measure that distinguishes between four content dimensions of perceived P-E fit: interest-contents (I-C) fit, needs-supplies (N-S) fit, demands-abilities (D-A) fit, and values-culture (V-C) fit. The central aim of our study was to examine whether the relationships between different P-E fit dimensions and educational outcomes can be accounted for by a higher-order factor that captures the shared features of the four fit dimensions. Relying on a large sample of university students in Germany, we found that students distinguish between the proposed fit dimensions. The respective first-order factors shared a substantial proportion of variance and conformed to a higher-order factor model. Using a newly developed factor extension procedure, we found that the relationships between the first-order factors and most outcomes were not fully accounted for by the higher-order factor. Rather, with the exception of V-C fit, all specific P-E fit factors that represent the first-order factors’ unique variance showed reliable and theoretically plausible relationships with different outcomes. These findings support the viability of a multidimensional conceptualization of P-E fit and the validity of our adapted instrument.

Sign in / Sign up

Export Citation Format

Share Document