We perform molecular dynamics simulations to study the structural relaxation dynamics of a model of viscous silica, the prototype of a strong glass former. We find that the melt dynamics are spatially heterogeneous regardless of whether the bulk relaxation is non-Arrhenius or Arrhenius, and cannot be understood as a statistical bondbreaking process. Further, we show that stringlike motion is su...

Many 4øAr/39Ar age spectra for alkali feldspars are significantly different from the model age spectra calculated for slowly cooled samples composed of diffusion domains of a single size, and the Arrhenius plots for these samples show departures from linearity that are inconsistent with diffusion from domains of equal size. The most plausible explanation for these discrepancies is the existence...

Arrhenius-type plots for multifragmentation process, defined as the transverse energy dependence of the single-fragment emission-probability, (ln(1/pb) vs 1/ √ Et), have been studied by examining the relationship of the parameters pb and Et to the intermediate-mass fragment multiplicity 〈n〉. The linearity of these plots reflects the correlation of the fragment multiplicity with the transverse e...

One of the most characteristic features of glass-forming liquids is the sharp slowing down of relaxation times, τ, upon cooling. In these materials relaxation dynamics exhibit a non-Arrhenius temperature dependence usually described by Vogel-Fulcher-Tamman (VFT) relation [1]. However, for majority of glassforming liquids it is impossible to fit data in the entire temperature range with a single...

As the human race will continue to explore the space by creating new space transportation means and sending them to other planets, the enhance of atmospheric reentry study is crucial. In this context, an analysis of mass recession rate of ablative materials for thermal shields of reentry spacecrafts is important to be carried out. The paper describes a new estimation method for calculating the ...

The NO2 fission reaction of gas phase R-HMX has been studied using a direct ab initio method within the framework of microcanonical variational transition state theory (μVT). The potential energy calculations were calculated using the hybrid nonlocal B3LYP density functional theory with the cc-pVDZ basis set. The calculated results show that the potential energy of breaking the axial NO2 groups...

[1] We develop and extend a theoretical framework to analyze the impacts of changes in temperature and alkalinity on the ocean‐atmosphere carbon partitioning. When investigating the impact of temperature, we assume that there is no change in the global ocean alkalinity. This idealized situation is probably most relevant on intermediate timescales of hundreds to thousands of years. Our results s...

Theoretical prediction of self-diffusion in a metal oxide in a wide range of thermodynamic conditions has been a long-standing challenge. Here, we establish that combining the formation free energies and migration barriers of all charged oxygen defects as calculated by density functional theory, within the random-walk diffusion theory framework, is a viable approach to predicting oxygen self-di...

Arrhenius plots of fluoride- and guanine-nucleotide-stimulated adenylate cyclase activity were linear in adipocyte plasma membranes from lean and obese (ob/ob) mice. Arrhenius plots of isoprenaline-stimulated adenylate cyclase activity in hepatic plasma membranes biphasic in both groups. The results were biphasic in membranes from lean mice but linear in membranes from obese mice. In contrast, ...