Activation energies and the arrhenius equation

Jensen, Finn

doi:10.1002/qre.4680010104

Cited by 108 publications

(44 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Some kinetic models such as Johnson-Mehl-Avrami-Kolmogorov (JMAK) model for the gas-solid reaction were adopted to simulate the evolution of kinetics [ 46 , 47 ]. Figure 4 d depicts the JMAK model through fitting the absorption curves and the Ea values for the hydrogenation reactions were finally calculated according to Arrhenius equation [ 48 ]. ln[−ln(1 − α )] = n ln k + n ln t k = A exp(− E a / RT ) where α is the fraction of Mg converted to MgH 2 with time, k is an effective kinetic parameter, and n is the Avrami exponent.…”

Section: Resultsmentioning

confidence: 99%

Realizing Hydrogen De/Absorption Under Low Temperature for MgH2 by Doping Mn-Based Catalysts

et al. 2020

View full text Add to dashboard Cite

Magnesium hydride (MgH2) has been considered as a potential material for storing hydrogen, but its practical application is still hindered by the kinetic and thermodynamic obstacles. Herein, Mn-based catalysts (MnCl2 and Mn) are adopted and doped into MgH2 to improve its hydrogen storage performance. The onset dehydrogenation temperatures of MnCl2 and submicron-Mn-doped MgH2 are reduced to 225 °C and 183 °C, while the un-doped MgH2 starts to release hydrogen at 315 °C. Further study reveals that 10 wt% of Mn is the better doping amount and the MgH2 + 10 wt% submicron-Mn composite can quickly release 6.6 wt% hydrogen in 8 min at 300 °C. For hydrogenation, the completely dehydrogenated composite starts to absorb hydrogen even at room temperature and almost 3.0 wt% H2 can be rehydrogenated in 30 min under 3 MPa hydrogen at 100 °C. Additionally, the activation energy of hydrogenation reaction for the modified MgH2 composite significantly decreases to 17.3 ± 0.4 kJ/mol, which is much lower than that of the primitive MgH2. Furthermore, the submicron-Mn-doped sample presents favorable cycling stability in 20 cycles, providing a good reference for designing and constructing efficient solid-state hydrogen storage systems for future application.

show abstract

Section: Resultsmentioning

confidence: 99%

Realizing Hydrogen De/Absorption Under Low Temperature for MgH2 by Doping Mn-Based Catalysts

et al. 2020

View full text Add to dashboard Cite

show abstract

“…The probability that a particular activated process has occurred after time t is p t . If this probability is small and the number of possible events N is large such that a = Npt (2) is finite then Poisson statistics may be used to give the probability that m such events have taken place after time t. This is ame-a m ! P, =-…”

Section: Physical Principle: a Time-dependent Theory O F Failurementioning

confidence: 99%

Death by a thousand cuts: The physics of device failure through a series of activated, microscopic events

Holden¹,

Allen²,

Beasley³

et al. 1988

Quality & Reliability Eng

View full text Add to dashboard Cite

A physical model describes device failure in terms of a series of n microscopic events (such as defect creation) which are describable in terms of an identifiable activation energy. The results show a 'Weibull like' time dependence, but the temperature dependence is not of the simple Arrhenius form. Application is made to the 'dark' leakage current in a PIN photodiode and to the deviation in threshold voltage in a MOSFET. In particular the threshold voltage is shown to depend on a series of activated processes, and the required number of such processes to cause failure increases with the width of the gate electrode.

show abstract

“…In this test we employ a type I progressive censoring scheme. The Arrhenius model 13 is used to describe the relationship between reliability and temperature stress. Methods for reliability estimation have already been suggested in this particular situation of temperature SSALT, see Gouno 14,15 .…”

Section: Introductionmentioning

confidence: 99%

Optimum step‐stress for temperature accelerated life testing

Gouno¹

2007

Quality & Reliability Eng

View full text Add to dashboard Cite

Step-stress accelerated life testing is a design strategy where the stress is modified several times during the test. In this work we address the problem of designing such a test. We focus on temperature accelerated life testing and we address the problems of setting the step duration and the stress levels. Assuming an Arrhenius model, maximum likelihood estimates of the parameters are computed. Relying on the properties of these estimators we compare different criteria for assessing the optimality of the plans produced. Some tables are presented to illustrate the method. For a fixed number of steps and a set of temperatures, a table of optimal length steps can be computed. For fixed step lengths, sets of temperatures leading to optimal plans are also available. Thus, this work provides useful tools to help engineers make decisions in testing strategy.

show abstract

Activation energies and the arrhenius equation

Cited by 108 publications

References 1 publication

Realizing Hydrogen De/Absorption Under Low Temperature for MgH2 by Doping Mn-Based Catalysts

Realizing Hydrogen De/Absorption Under Low Temperature for MgH2 by Doping Mn-Based Catalysts

Death by a thousand cuts: The physics of device failure through a series of activated, microscopic events

Optimum step‐stress for temperature accelerated life testing

Contact Info

Product

Resources

About