The Decomposition of some RDX and HMX Based Materials in the One-Dimensional Time to Explosion Apparatus. Part 1. Time to Explosion and Apparent Activation Energy

2006 ◽  
Vol 31 (6) ◽  
pp. 435-441 ◽  
Author(s):  
Michael Robert Williams ◽  
Mariana Violetta Matei
Keyword(s):  
Activation Energy ◽  
Apparent Activation Energy ◽  
One Dimensional ◽  
The One ◽  
Apparatus Part

scholarly journals Influence of dimensionality on phase transition in VO2 nanocrystals

2013 ◽  
Vol 45 (3) ◽  
pp. 305-311 ◽  
Author(s):  
V.A. Blagojevic ◽  
N. Obradovic ◽  
N. Cvjeticanin ◽  
D.M. Minic
Keyword(s):  
Phase Transition ◽  
Activation Energy ◽  
Transition Temperature ◽  
Apparent Activation Energy ◽  
Phase Transition Temperature ◽  
Bulk Material ◽  
Two Dimensional ◽  
Lower Phase ◽  
One Dimensional ◽  
Simultaneous Movement

Hydrothermally synthesized one-dimensional and two-dimensional nanocrystals of VO2 undergo phase transition around 65?C, where temperature and mechanism of phase transition are dependent on dimensionality of nanocrystals. Both nanocrystalline samples exhibit depression of phase transition temperature compared to the bulk material, the magnitude of which depends on the dimensionality of the nanocrystal. One-dimensional nanoribbons exhibit lower phase transition temperature and higher values of apparent activation energy than two-dimensional nanosheets. The phase transition exhibits as a complex process with somewhat lower value of enthalpy than the phase transition in the bulk, probably due to higher proportion of surface atoms in the nanocrystals. High values of apparent activation energy indicate that individual steps of the phase transition involve simultaneous movement of large groups of atoms, as expected for single-domain nanocrystalline materials.

Kinetic Study on Phosphate Enrichment Behavior in CaO–SiO2–FeO–Fe2O3–P2O5 Steelmaking Slags

2018 ◽  
Vol 37 (5) ◽  
pp. 477-486
Author(s):  
Jin-yan Li ◽  
Mei Zhang ◽  
Min Guo ◽  
Xue-min Yang
Keyword(s):  
Activation Energy ◽  
Apparent Activation Energy ◽  
Crystallization Behavior ◽  
Crystallization Rate ◽  
Avrami Equation ◽  
One Dimensional ◽  
Thermal Crystallization ◽  
Steelmaking Slags ◽  
Cooling Schedules ◽  
Kinetics Of

AbstractThe iso-thermal crystallization behavior of phosphate-enriched phase has been experimentally investigated in the rapidly quenched CaO–SiO2–FeO–Fe2O3–P2O5 steelmaking slags under different cooling schedules. The experimental results indicate that increasing endpoint temperature from 1453 to 1533 K and prolonging holding time from 2 to 60 min can result in an increasing tendency of the size of phosphate-enriched phase in the shape of one-dimensional rod. The crystallization kinetics of phosphate-enriched phase in steelmaking slags has been described by Avrami equation. The Avrami constant $$n$$ was obtained to be 0.472, while the crystallization rate constant $$k$$ was recommended as $$\ln k{\rm{= 57}}{\rm{. 40 + 12,273}}{\rm{. 96}}/T - {\rm{8}}{\rm{. 25}}\,\ln T - {\rm{5}}{\rm{. 5}\times{\rm 10}^{- 3}}T$$. Thus, the apparent activation energy $$E$$ of crystallization is recommended as $$E{\rm{= 537}}{\rm{. 60}} - {\rm{206}}{\rm{. 015}}T$$ kJ/mol.

The Decomposition of some RDX and HMX Based Materials in the One Dimensional Time to Explosion Apparatus. Part 2. Estimating the Violence of the Cook-Off Event

2007 ◽  
Vol 32 (1) ◽  
pp. 7-15 ◽  
Author(s):  
Michael Robert Williams ◽  
Mariana Violetta Matei
Keyword(s):  
One Dimensional ◽  
The One ◽  
Apparatus Part

Theory of thermal explosions with simultaneous parallel reactions I. Foundations and the one-dimensional case

1984 ◽  
Vol 393 (1804) ◽  
pp. 85-100 ◽  
Keyword(s):  
Activation Energy ◽  
Dimensionless Parameter ◽  
Exothermic Reactions ◽  
One Dimensional ◽  
Temperature Excess ◽  
Parallel Reactions ◽  
The One ◽  
Definition Of ◽  
Thermal Explosions ◽  
Thermal Explosion Theory

Many real, exothermic systems involve more than one simultaneous reaction. Even when they are chemically independent, interactions must arise through their several responses to the collective generation of heat. A simple and unifying approach is possible to the behaviour of such systems below and up to criticality. It introduces a communal activation energy E as the basis for dimensionless quantities ( θ, δ, ϵ and so on) but otherwise involves only familiar ideas from basic thermal explosion theory. The definition of E is E = RT 2 d (In Z )/d T , where Z = Ʃ Z i . Here, Z is the rate of energy release per unit volume (the power density) by the whole system and Z i is the contribution of the constituent i . This enables us to define and use the conventional dimensionless parameter δ for the whole system and for its constituent reactions. We illustrate affairs by considering a pair of concurrent, exothermic reactions; heat is transferred solely by conduction towards the faces (temperature T a ) of an infinite slab of thickness 2 a and conductivity k . For a constituent reaction ( i = 1, 2 here) δ i = ( Ea 2 / k RT 2 a ) Z i ( T a ) and for the whole system δ = δ 1 + δ 2 (+...) for two (or more) reactions. We find that the condition δ > δ cr guarantees instability, where δ cr is always less than 0.878. The bounds 0.65 < δ cr < 0.878 are good enough for a substantial range of relative sizes of activation energy 0.2 < E 1 / E 2 < 5. We also pursue the problem numerically and present solutions for critical δ and critical central temperature excess over the whole composition range for a pair of simultaneous exothermic reactions.

scholarly journals Numerical estimation of thermal ignition conditions for reactive medium with Gaussian distribution of activation energy

2021 ◽  
Vol 2119 (1) ◽  
pp. 012102
Author(s):  
I G Donskoy
Keyword(s):  
Activation Energy ◽  
Gaussian Distribution ◽  
Critical Conditions ◽  
Differential Heat ◽  
Reactive Medium ◽  
One Dimensional ◽  
Analytical Approximations ◽  
Gaussian Distribution Function ◽  
The One ◽  
Thermal Explosion Theory

Abstract The article investigates the solutions of the one-dimensional stationary integro-differential heat equation. The source of heat release is determined through the Gaussian distribution function of the activation energy. In such a statement, the critical conditions for the existence of a bounded solution depend on the distribution variance. With the help of numerical methods, such dependences are obtained; for their explanation, the analytical approximations of the thermal explosion theory are used.

Exploring the Multidimensional Facets of Authoritarianism: Authoritarian Aggression and Social Dominance Orientation

2008 ◽  
Vol 67 (1) ◽  
pp. 51-60 ◽  
Author(s):  
Stefano Passini
Keyword(s):  
Social Dominance ◽  
Factor Model ◽  
Three Dimensional ◽  
Social Dominance Orientation ◽  
Model Fit ◽  
Regression Analyses ◽  
One Dimensional ◽  
Confirmatory Factor ◽  
The One ◽  
Better Than

The relation between authoritarianism and social dominance orientation was analyzed, with authoritarianism measured using a three-dimensional scale. The implicit multidimensional structure (authoritarian submission, conventionalism, authoritarian aggression) of Altemeyer’s (1981, 1988) conceptualization of authoritarianism is inconsistent with its one-dimensional methodological operationalization. The dimensionality of authoritarianism was investigated using confirmatory factor analysis in a sample of 713 university students. As hypothesized, the three-factor model fit the data significantly better than the one-factor model. Regression analyses revealed that only authoritarian aggression was related to social dominance orientation. That is, only intolerance of deviance was related to high social dominance, whereas submissiveness was not.

FURTHER TESTS OF VALIDITY FOR THE ONE-DIMENSIONAL HONG'S PSYCHOLOGICAL REACTANCE SCALE

2007 ◽  
Vol 101 (7) ◽  
pp. 871 ◽  
Author(s):  
PETER K. JONASON
Keyword(s):  
Psychological Reactance ◽  
One Dimensional ◽  
The One

Adiabatic large polarons in anisotropic molecular crystals

2011 ◽  
Vol 35 (1) ◽  
pp. 15-27
Author(s):  
Zoran Ivić ◽  
Željko Pržulj
Keyword(s):  
Energy Transfer ◽  
Effective Mass ◽  
Molecular Crystals ◽  
Single Chain ◽  
Proper Understanding ◽  
One Dimensional ◽  
Interchain Coupling ◽  
Large Polaron ◽  
The One

Adiabatic large polarons in anisotropic molecular crystals We study the large polaron whose motion is confined to a single chain in a system composed of the collection of parallel molecular chains embedded in threedimensional lattice. It is found that the interchain coupling has a significant impact on the large polaron characteristics. In particular, its radius is quite larger while its effective mass is considerably lighter than that estimated within the one-dimensional models. We believe that our findings should be taken into account for the proper understanding of the possible role of large polarons in the charge and energy transfer in quasi-one-dimensional substances.

A New Algorithm for the One-Dimensional Cutting Stock Problem

2006 ◽  
Vol 1 (2) ◽  
pp. 78-84
Author(s):  
Sarath. B. Siyambalapitiya ◽  
Keyword(s):  
Cutting Stock Problem ◽  
Cutting Stock ◽  
One Dimensional ◽  
The One
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