An empirical nonreactive force field has been developed for molecular dynamics (MD)/Monte Carlo simulation of the formation, diffusion, and agglomeration of point defects in the crystal lattice of the alpha modification of hexahydro-1,3,5-trinitro-1,3,5 triazine (RDX) using flexible molecules. Bond stretching and angle bending are represented by Morse and harmonic functions, and torsion by a truncated cosine series. Nonbonded interactions, both inter- and intramolecular, are described by Buckingham potentials separately parametrized. Intermolecular electrostatic interactions are treated via a Coulomb term coupled with a smooth 15.0 A cutoff radius. Parameters were taken in part from earlier published works and were determined partly by fitting to known molecular and crystal properties of RDX. In MD simulations at constant pressure and temperature, the model was able to stabilize and maintain the correct crystal structure, symmetry, and molecular conformation of alpha-RDX. Vibrational frequencies, lattice binding energy and dimensions, coefficients of thermal expansion, and several unusually short intermolecular distances are all reproduced in satisfactory agreement with experimental data.
A key trend that has characterized implementation of the international agenda to regulate derivatives has been the emergence of a number of disputes over the territorial scope of regulation, as different countries have sought to extend their regulatory oversight over firms and markets that are not legally domiciled in their jurisdiction. What explains the emergence and continuation of these extraterritorial measures in the regulation of global OTC derivatives markets? This chapter addresses this question by exploring the “regulatory land grab” that has characterized the rules introduced in the United States and the European Union to regulate foreign dealers, CCPs, and trading venues. This chapter will argue that the different degrees of extraterritoriality that have emerged in the post-crisis agenda reflect the challenges that regulatory authorities have faced to implement the new prudential agenda in a manner that addresses the highly internationalized nature of derivatives markets.
Spatial reasoning is an ability that people utilize on a daily basis, that has also been linked to performance in Science, Technology, Engineering, and Mathematics (STEM) fields. However, there are very few widely available opportunities to train spatial reasoning skills that have been proven to be effective tools. As a first step in the validation process, this study sought to establish whether performance on a measure of intrinsic and dynamic spatial reasoning ability was related to performance within Optica, a mobile puzzle game. To investigate this relationship, 168 middle school students participated in a within-subjects study over three days. The results of this study have been promising, as our analysis indicated that there was a significant relationship between the number of levels completed in Optica and score on the Purdue Spatial Visualization Test-Revised: Visualization of Rotations (Revised PSVT: R).
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